ArticlePDF Available

Isopoda Valvifera: Diagnoses and Relationships of the Families

Authors:

Abstract and Figures

Eleven families of the isopod suborder Valvifera are diagnosed, and a key to differentiate them is presented. Three families, Antarcturidae, Rectarcturidae, and Arcturididae, are erected as new on the basis of a cladistic analysis of 14 families, genera, and genus-groups. Phylogenetic relationships between the families are suggested. The genera of each family, 81 in all, are listed. The generic name Austridotea, previously a nomen nudum, is made available within the Idoteidae. Differentiation of the families is based on fusion of the head and pereionite 1, length of the peduncle of pleopod 1, the male first pleopods, and fusion of the penes. Three families (Chaetiliidae, Holognathidae, Idoteidae) have pereionite 1 free from the head; pereiopod 1 subchelate, similar to others or larger; all pleopods simple and similar; and penes free or a basally fused penial plate. Those families with pereionite 1 fused to the head, pereiopod 1 smaller than other pereiopods and with different structure, an elongate pleopod 1 peduncle, and a fused penial plate have either the exopod of the male pleopod 1 laminar and excavate laterally (Arcturidae) or the exopod thickened and diagonally grooved (Arcturididae, Antarcturidae, Austrarcturellidae, Holidoteidae, Pseudidotheidae, Rectarcturidae, Xenarcturidae).
Content may be subject to copyright.
tion presents a phylogeny of the suborder, di-
agnoses its eleven families of which three are
new, provides a key for their differentiation,
lists the genera in each family, and briefly
reviews the recent literature.
I offer the work to establish a broad taxo-
nomic framework now rather than await de-
scriptions and publication of many new taxa
which will take some time. First, the taxa cho-
sen for analysis are discussed and justified
in terms of their perceived synapomorphies.
Next, characters and their states are discussed
and figured. Finally, a new classification is
derived from the cladistic analysis and all the
families diagnosed. A key to separate them
is presented. All valid genera are listed and
the name of one idoteid genus is formalised.
CLADISTIC ANALYSIS
Analytical Methods
The information presented here is based on
examination of representatives of numerous
species representing most genera in the col-
lections of Museum Victoria. These have been
supplemented by type specimens on loan
from the U.S. National Museum of Natural
History. The conclusions are based on exam-
ination of type species of most genera, nu-
The Valvifera is a suborder of marine, and
rarely estuarine, isopods inhabiting algal and
benthic environments from the intertidal to
the deep sea. They reach their greatest di-
versity in cold waters, being abundant on
temperate shores, Antarctica, and the ocean
basins. There are few tropical species. Forms
include the herbivorous sea-centipedes
(Idoteidae) and bizarre filter-feeding arc-
turids. The Valvifera (about 520 described
species) comprise 81 genera presently in-
cluded in seven families. There has never
been any doubt about the monophyly of the
Valvifera, the suborder erected by Sars (1882)
for isopods in which the uropods hinge lat-
erally along the length of the pleon and pleo-
telson so enclosing the pleopods in a
branchial chamber.
In the course of taxonomic studies on the
many undescribed valviferan isopods of Aus-
tralia and adjacent seas it became apparent
that (1) the family-level arrangement had
changed over the past two decades, (2) no
modern key to the families existed, (3) some
species commonly referred to the largest fam-
ilies, Idoteidae and Arcturidae, could be
placed in other groups worthy of family sta-
tus, and (4) the relationships between them
had been rarely investigated. This contribu-
JOURNAL OF CRUSTACEAN BIOLOGY, 21(1): 205–230,2001
ISOPODA VALVIFERA: DIAGNOSES AND RELATIONSHIPS OF
THE FAMILIES
Gary C. B. Poore
Museum Victoria, GPO Box 666E, Melbourne, Victoria 3001, Australia
(e-mail: gpoore@museum.vic.gov.au)
ABSTRACT
Eleven families of the isopod suborder Valvifera are diagnosed, and a key to differentiate them
is presented. Three families, Antarcturidae, Rectarcturidae, and Arcturididae, are erected as new on
the basis of a cladistic analysis of 14 families, genera, and genus-groups. Phylogenetic relation-
ships between the families are suggested. The genera of each family, 81 in all, are listed. The generic
name Austridotea, previously a nomen nudum, is made available within the Idoteidae. Differentia-
tion of the families is based on fusion of the head and pereionite 1, length of the peduncle of pleo-
pod 1, the male first pleopods, and fusion of the penes. Three families (Chaetiliidae, Holognathi-
dae, Idoteidae) have pereionite 1 free from the head; pereiopod 1 subchelate, similar to others or
larger; all pleopods simple and similar; and penes free or a basally fused penial plate. Those fam-
ilies with pereionite 1 fused to the head, pereiopod 1 smaller than other pereiopods and with dif-
ferent structure, an elongate pleopod 1 peduncle, and a fused penial plate have either the exopod
of the male pleopod 1 laminar and excavate laterally (Arcturidae) or the exopod thickened and di-
agonally grooved (Arcturididae, Antarcturidae, Austrarcturellidae, Holidoteidae, Pseudidotheidae,
Rectarcturidae, Xenarcturidae).
205
merous species from Australasian seas, the
Southern Ocean, and elsewhere, and analy-
sis of the literature. Phylogenetic (cladistic)
methods were used to generate cladograms of
monophyletic groups as hypotheses of the re-
lationships between family-level taxa. An in-
terim cladistic analysis of all the genera (un-
published) has failed to result in a fully re-
solved cladogram of relationships because of
the high level of homoplasy shown by many
trivial characters. Nevertheless, the clado-
grams have suggested some persistent high-
level groupings which are or might be as-
signed family ranking. The approach de-
scribed here is a phylogenetic analysis of
these groupings (families, genera, or groups
of genera) each of which is unambiguously
monophyletic and holophyletic. The charac-
ters that define these groups are those asso-
ciated with reproduction (especially male
pleopods), feeding (pereiopods), fusion of
body segments, and general habitus. In par-
ticular these characters are those that could
define (a priori) large groups of genera and
so contribute to a family-level classification.
They contrasted with characters which varied
in similar ways in different groups and were
undoubtedly homoplasous, e.g., number of ar-
ticles in maxillipeds or antennal flagella, or
number of uropodal rami.
The phylogenetic analysis program Paup*
4.0 (beta version for Windows) (Swofford,
1998) was used to establish relationships of
14 taxa in order to derive a practical classi-
fication of monophyletic family-level taxa.
Aheuristic search was made using default op-
tions, and a strict consensus tree was gener-
ated. Characters were treated as unweighted
and unordered (Table 1). The matrix was then
treated to a bootstrap analysis using a heuris-
tic search. A 50% majority-rule consensus
tree was constructed of all bootstrap trees.
The cladogram was rooted against a hy-
pothetical ancestor. The valviferans are a
highly specialised derived group with rela-
tionships to flabelliferan isopod families
(Wägele, 1989; Brusca and Wilson, 1991).
The hypothetical ancestor is based, therefore,
on more generalised families such as
Cirolanidae and Sphaeromatidae.
In the following discussions of taxa and
characters the word ‘idoteoid’ is used as a
shorthand for the families Idoteidae, Chaetili-
idae, and Holognathidae. The phylogenetic
analysis does not support the monophyly of
this group, but the term is used to contrast
these families with the ‘arcturoid’ families
which undoubtedly belong to a monophyletic
clade. The words ‘arcturid’ and ‘antarcturid’
are used in the narrow senses which anticipate
the classification resulting from the analysis.
Taxa Used In Analysis
Any phylogenetic analysis depends on hav-
ing taxa of unambiguous monophyly. This is
not the case for all the families of Valvifera
as presently understood although for others,
especially small ones, clear synapomorphies
have been defined (although not always in
phylogenetic language). Fourteen families,
genera, and genus-groups (listed in Table 2
and printed in boldface type below) were se-
lected. The genera represented by the two
genus-groups (Arcturus-group and Antarc-
turus-group) are those listed in Arcturidae and
Antarcturidae in the Systematics section. All
taxa are scored for the most plesiomorphic
states found, but examples of differences
from these states are considered in the dis-
cussion of characters. The larger groups are
represented by basal taxa with many ple-
siomorphic character states in common. Con-
siderable divergence from the basal taxa
within families has resulted in convergence
in several characters. For example, in all the
taxa treated here the maxillipedal palp is of
five articles, but fusion to as few as one ar-
ticle has occurred in three families. The max-
illiped and other characters that converge in
this way and are therefore phylogenetically
uninformative are discussed with the rest be-
low. Justification of the taxa chosen necessi-
tates some discussion of the characters pur-
sued in more detail in the next section.
The major division of the suborder is based
on two key characters, but others are more
or less correlated with them: fusion of pereio-
nite 1 to the head and the structure of pleo-
pod 1. In three families (Idoteidae, Chaetili-
idae, Holognathidae) pereionite 1 is free
from the head and the pleopod peduncles are
short and similar (Fig. 1a–d). Pereiopod 1 in
these families is a subchelate limb not much
different in size from other pereiopods (Fig.
2a, b). The body tends to be flattened because
of lateral extension of dorsal coxal plates. The
systematics of these three families is rela-
tively well established, and each is treated as
a monophyletic taxon in the analysis.
The Idoteidae are probably the archetypal
206 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 21, NO. 1, 2001
POORE: FAMILIES OF ISOPODA VALVIFERA 207
Table 1. Characters and character states used in cladistic analysis of valviferan families. Each character is termi-
nated by a colon and states, 0, 1, etc. separated by semicolon. All characters are treated as unordered. Four charac-
ters marked * are not used in family diagnoses.
1. Body: 0, straight, more or less flattened or semicylindrical, all pereiopods ambulatory; 1, straight, cylindrical
or vaulted, pereiopods 2–4 differentiated from 5–7; 2, flexed between pereionites 4 and 5, pereiopods 2–4
differentiated from 5–7.
2. Body: 0, tapering posteriorly; 1, parallel-sided over most of length.
3. Head and pereionite 1: 0, free; 1, fused.
4. Head: 0, more or less cylindrical or semicylindrical; 1, with prominent flat lateral lobes, sometimes with
ocular notch.
5. Pereionite 4: 0, similar in length to pereionite 3; 1, at least 1.5 times as long as pereionite 3 (in males often
much longer).
6. Pleonites: 0, pleonites 1–4 articulating with each other and fused pleotelson (others sometimes indicated but
not articulating); 1, pleonites 1–3 articulating with each other and fused pleotelson (others sometimes indicated
but not articulating); 2, pleonites 1 and 2 articulating with each other and fused pleotelson (others sometimes
indicated but not articulating); 3, pleonite 1 articulating with fused pleotelson; 4, all pleonites fused
into pleotelson.
7. *Pleonite 1: 0, of similar length to pleonite 2; 1, longer than pleonite 2.
8. Dorsal sculpture: 0, smooth or variously spinose; 1, strongly spinose with at least dorsal and dorsolateral pairs
of spines, often dominated by pair near end of pleotelson.
9. Pleotelson: 0, without dorsolateral ridges ending in mediodorsal posterior spine; 1, with dorsolateral ridges
usually ending in mediodorsal posterior spine.
10. Dorsal coxal plates 2–7 (rarely only 5–7): 0, more or less ventrally expanded over bases of pereiopods (body
flattened); 1, obsolete, bases of pereiopods exposed (body usually cylindrical).
11. *Dorsal coxal plates 2–4: 0, visible dorsally (same as dorsal coxal plates 5–7); 1, obsolete (pereionites 2–4
with terga reaching lateral margin).
12. Mouthparts and pereiopod 1: 0, visible in lateral view; 1, enclosed in lateral view by lateral plates of head
and pereionite 1.
13. Eyes: 0, well developed; 1, reduced or lost.
14. Antenna 2 flagellum: 0, multiarticulate; 1, of 2 or 3 articles plus distal claw.
15. Maxillipedal epipod: 0, as long as or longer than wide; 1, shorter than wide.
16. *Maxillipedal palp article 3: 0, at most 1.5 times as wide as article 4; 1, medially lobed, at least twice as wide
as article 4.
17. Pereiopods: 0, pereiopod 1 slightly differentiated from pereiopod 2, its propodus broader than in pereiopod 2;
1, pereiopods differentiated, 1, 1–3, 1–5, or 1–6 subchelate; 2, pereiopod 1 a gnathopod, pereiopods 2–4
elongated, differentiated from ambulatory pereiopods 5–7.
18. Pereiopods 2–4: 0, with irregular fine setae and marginal robust setae; 1, with paired long setae along posterior
margins evenly and well developed; 2, with scattered and uneven long setae along posterior margins; 3,
raptorial, articles broad and with posterior robust setae.
19. Pereiopods 2–4: 0, with prominent dactylus, unguis short; 1, with short dactylus, unguis longer and setiform;
2, with minute dactylus, unguis setiform.
20. Pereiopod 4: 0, similar to pereiopod 3; 1, shorter and more spinose than pereiopods 3 and 5; 2, shorter and
less setose than pereiopods 2 and 3; 3, different from pereiopod 3, similar to pereiopod 5.
21. Pereiopod 1 dactylus: 0, evenly curved; 1, with anterior lobe.
22. Pereiopods of males: 0, with dense fur of fine setae; 1, without dense fur of fine setae.
23. Uropodal exopod (smaller ramus): 0, ovate, fringed with setae (if present); 1, tapering (with terminal
setae only).
24. Uropod: 0, exopod more than half as long as endopod, with at least three distal setae, exopod with few
marginal setae; 1, exopod very short, both rami each bearing a single, prominent robust seta.
25. Oostegites 5: 0, functional; 1, vestigial lobes; 2, absent.
26. Oostegites 1–4: 0, not supported by coxal lobes; 1, supported by coxal lobes.
27. Penes: 0, paired, widely separate; 1, fused basally as a penial plate but divided over most of length; 2, fused
as a single penial plate, rarely divided only apically.
28. Penial plate: 0, apically simple or barely slit; 1, apically bifid and splayed.
29. Pleopod 1 peduncle: 0, short (similar to other pleopods); 1, more elongate than on other pleopods.
30. Pleopod 1 with marginal setae on rami: 0, longer than or equal to length of rami; 1, much shorter than length
of rami.
31. Pleopod 1 exopod of male: 0, laminar; 1, thickened and with groove on posterior face.
32. Pleopod 1 exopod of male: 0, with few simple setae along straight lateral margin; 1, with overlapping rows of
simple and plumose setae along lateral margin, terminating at subdistal excavation.
33. Pleopod 1 of male with groove on posterior face of exopod: 0, ending distolaterally or laterally on simple
margin; 1, ending in deep subdistal excavation; 2, ending on distolateral lobed tip, separated from most of
lateral margin by notch; 3, ending on basally derived branch of exopod; 4, ending on tapering distolateral
apical extension.
34. Pleopod 1 exopod of male: 0, without lateral excavation; 1, with lateral excavation.
35. Pleopod 2 of male with appendix masculina: 0, about as long as endopod; 1, twice length of endopod.
36. Pleopod 2 of male with appendix masculina: 0, basally less than half width of endopod; 1, basally as wide or
wider than endopod.
37. *Pleopod 2 of male with appendix masculina: 0, apically tapering (not club-shaped); 1, apically club-shaped.
valviferans, plesiomorphic for most charac-
ters (Poore and Lew Ton, 1993). The most
plesiomorphic genera are Austridotea, a
nomen nudum diagnosed here as a new genus,
and Idotea which were used as sources for
most characters. The Chaetiliidae are mor-
phologically diverse but Saduria provided
most plesiomorphic states. The Holognath-
idae are generally uniform for the characters
of family significance (Poore and Lew Ton,
1990).
In all other families pereionite 1 is fused
to the head (Fig. 1e–h) and pereiopod 1 is at
least reduced in size and often very different
in structure from those following (Fig. 2c, d).
The general body shape tends to be cylindri-
cal and often sculptured and/or spinose. Body
form is highly variable, but there is a strong
division among the families of this second
group based on the structure of the male pleo-
pod 1. In the Arcturus-group, both rami of the
male pleopod 1 are laminar and the exopod
has a lateral excavation (Fig. 3f). The mono-
typic Amesopodidae, which includes only
Amesopous richardsonae Stebbing, 1905, is
similar. The only character that differentiates
this species from highly derived arcturid gen-
era like Neastacilla is the loss of pereiopods 3
and 4 (seen in another arcturid genus), and the
family is treated as a junior synonym of Arc-
turidae, sensu stricto.In most remaining arc-
turoids, the Antarcturus-group, and Austrarc-
turellidae, Pseudidotheidae, and Xenarc-
turidae, the exopod of the male pleopod 1 is
thickened, especially basally, variously sculp-
tured and setose and always has an oblique
groove opening distally (Fig. 3b, c, e; Poore,
1998: Fig. 3 g, h). These four taxa are ac-
cordingly included in the analysis.
While several genera resemble Antarcturus
closely and can be represented by it when
scoring the characters selected, others do not.
Most arcturoids have a more or less elevated
anterior body, flexing between pereionites 4
and 5 to lift pereiopods 2–4, which bear fil-
tering setae, off the substrate. This is seen in
extreme in Antarcturus where the ventral sur-
face of the anterior pereionites is held hori-
zontally and uppermost while the animal is
feeding (Wägele, 1987). In other genera this
flexion does not exist, although pereiopods
2–4 may be similarly differentiated from
pereiopods 5–7. These (Holidotea, Aus-
troarcturus, and Rectarcturus) are included
as separate taxa in the analysis. A fourth
genus, Arcturides, which is also straight rather
than flexed but has six pairs of similar
pereiopods, is also included as a monophyletic
taxon. Another, Neoarcturus, has been shown
in a work submitted elsewhere to be similar
to Holidotea and Austroarcturus and is also in-
cluded. Finally, the genus Dolichiscus, which
shares features of both the Antarcturus-group
and Austrarcturellidae, is treated indepen-
dently.
Characters
Thirty-seven characters were included in
the data matrix, but 13 of these are autapo-
morphies. Twenty-four (with 2–5 unordered
states) are therefore parsimony-informative.
As in most isopods the body of idoteoids
is straight and more or less flattened. The
pereiopods, except perhaps the first, are am-
208 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 21, NO. 1, 2001
Table 2. Character matrix used in cladistic analyses of families and genus-groups of Valvifera.
Character numbers 1234567891123456789212345678931234567
hypanc 0000000000000000000000000000000000000
Holognathidae 0100010000000000000100000010000000000
Idoteidae 0000020000000000000000000010010000000
Chaetiliidae 0001000000001010100001000000000000100
Arcturus-group 2010140001010100210001100020100001010
Austroarcturus 1010030001100101221001112121101110000
Holidotea 1010040001100101221001112121101120000
Neoarcturus 2010040001000100211001112121101110001
Antarcturus-group 2010040101000000210001102120101000000
Rectarcturus 1010040001000100211001102020101000000
Dolichiscus 2010031011000000211011102120101000000
Austrarcturellidae 2010040011000100212211101120101030100
Xenarcturus 1010040001000100210301102020101040000
Pseudidothea 1010040001000100230001102020101040000
Arcturides 1010040001000100200001102120101040000
POORE: FAMILIES OF ISOPODA VALVIFERA 209
Fig. 1. Habitus of some families of Valvifera. a, Euidotea durvillei (Idoteidae); b, Austroarcturus africanus (Holidotei-
dae); c, Chaetilia tasmanica (Chaetiliidae); d, Cleantioides striata (Holognathidae); e, Austrarcturella oculata (Aus-
trarcturellidae); f, Rectarcturus sp. (Rectarcturidae); g, Antarcturus sp. (Antarcturidae); h, Neastacilla sp.(Arcturidae).
210 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 21, NO. 1, 2001
Fig. 2. Pereiopods 1. a, Idotea (Idoteidae); b, Chaetilia (Chaetiliidae); c, new genus (Antarcturidae); d, Neastacilla
(Arcturidae); e, dactylus only, Austrarcturella (Austrarcturellidae). Pereiopods 2. f, Austroarcturus (Holidoteidae); g,
Pseudidothea (Pseudidotheidae); h, new genus (Antarcturidae); i, Austrarcturella (Austrarcturellidae) with detail of
dactylus. Pereiopods 4. j, Idotea (Idoteidae); k, Zenobianopsis (Holognathidae); l, Austrarcturella (Austrarcturelli-
dae) with detail of dactylus. Uropods. m, Chaetilia (Chaetiliidae); n, Neastacilla (Arcturidae); o, Austroarcturus (Holi-
doteidae); p, Pentidotea (Idoteidae).
bulatory (character 1, state 0; Fig. 1a, c, d).
Most Idoteidae are herbivorous, and
pereiopods play little part in feeding. Most
arcturoids on the other hand are flexed dor-
sally between pereionites 4 and 5, and
pereiopods 2–4 are differentiated from 5–7
(state 2; Fig. 1e, g, h). This flexion enables
the filtering pereiopods 2–4 to be held above
the substrate for feeding. An intermediate
condition occurs in some genera where the
body is straight, cylindrical, or vaulted, but
the anterior pereiopods are partially differ-
entiated (state 1; Fig. 1b, f). It is possible that
this state is a stage on the way from benthic
feeding, using the setose limbs to scrape
minute epiflora from the substrate, to plank-
ton feeding. The alternate hypothesis is that
the straight body has been secondarily de-
rived and another use found for reduced fil-
tering setae. The condition is seen, for ex-
ample, in two very different genera like Aus-
troarcturus and Xenarcturus, which feed on
the benthos. The body in Arcturus and
Antarcturus is sigmoid, there being only a
slight change in angle between the longitu-
dinal axes of pereionites 4 and 5 while the an-
imal is at rest. While it is probable that this
condition evolved only once in the arcturoids,
there are differences in degree between the
state in Antarcturus (Fig. 1g) and Arcturus
and that in more derived arcturids. In
Neastacilla (Fig. 1h) and Parastacilla, for ex-
ample, these two segments are strongly genic-
ulate, virtually at right angles to each other
with no possibility of the animal resting hor-
izontally. This highly derived condition oc-
curs only within the Arcturus-group and is not
scored.
The typical isopod is oval in dorsal view,
widest at pereionites 3 and 4, with the body
tapering posteriorly to the end of the pleo-
telson (character 2, state 0; Fig. 1c). In the
Holognathidae the body including the pleo-
telson is parallel-sided over most of its length
(state 2; Fig. 1d). This is an autapomorphy
of this family (Poore and Lew Ton, 1990). In
members of some other families the pereion
may be more or less parallel-sided or the body
cylindrical but the pleotelson rarely tapers to
a rounded apex.
Fusion of pereionite 1 with the head (char-
acter 3, state 1; Fig. 1e–h) is a synapomorphy
of the arcturoids, without exception. The
same condition is seen convergently in two
unrelated genera of Idoteidae, Crabyzos
(Poore and Lew Ton, 1993) and Lyidotea
(Hale, 1929) but in these cases is not associ-
ated with the smaller pereiopod 1.
Prominent flat lateral lobes on the head,
sometimes with an ocular notch (character 4,
state 1; Fig. 1c) are a synapomorphy of
Chaetiliidae (Poore, 1985), all other families
having the head more or less cylindrical or
semi-cylindrical (state 0).
Pereionite 4 is of a similar length to other
pereionites in all valviferans (character 5,
state 0) except in the Arcturus-group (Fig.
1h). In this group, pereionite 4 is usually at
least 1.5 times as long as pereionite 3 and in
males often much longer (state 1; Fig. 1h).
The degree of elongation varies, but in
species of the flattened genus Arcturinoides
no elongation is evident (Kensley, 1977). This
one case must be treated as a reversal.
Fusion of the pleonites (character 6) varies
considerably between genera. Early workers
did not differentiate between pleonal sutures
that allowed articulation between segments
and those that were simply cuticular indica-
tions of divisions between fused pleonites.
Poore and Lew Ton (1990, 1993) resolved
this differentiation for the Holognathidae and
Idoteidae, where it is important in defining
genera. On the assumption that fusion is more
derived than articulation, families were
scored for the most plesiomorphic state
known. In no valviferan family are five
pleonites free and articulating. Fusion of
pleonite 6 with the telson is a synapomorphy
of the Isopoda. The most plesiomorphic con-
dition, where pleonites 1–4 articulate with
each other and with fused remaining seg-
ments of the pleotelson, is seen in some
Chaetiliidae (state 0; Fig. 1c). Other pleonites
are sometimes indicated by complete or lat-
eral suture lines but do not articulate. As
many as three free pleonites is the case in
Holognathidae (state 1; Fig. 1d). The most
plesiomorphic state in Idoteidae is where two
pleonites articulate with each other and the
pleotelson. In this family as many as three
other pleonites may be indicated by full or
partial sutures (state 2) or all pleonites may
be fused. In most arcturoids all pleonites are
fused into the pleotelson, others being some-
times indicated by lateral incisions (state 4;
Fig. 1f–h). A rare intermediate condition in
arcturoids, where only the first pleonite ar-
ticulates with the pleotelson, is found in Aus-
troarcturus (Poore, in preparation) and most
POORE: FAMILIES OF ISOPODA VALVIFERA 211
species of Dolichiscus (state 3; Poore, 1998).
These two genera are not otherwise similar, and
it seems probable that the state is a reversal.
Pleonite 1 is generally of a similar length
to pleonite 2 (character 7, state 0), but it is
longer than pleonite 2 (state 1) in Dolichis-
cus (Poore, 1998).
Specific features of body sculpture are gen-
erally too variable to be useful in a family-
level analysis. Idoteids and holognathids tend
to be smooth although dorsal crests are seen
in some idoteid genera. Some genera of
Chaetiliidae are quite smooth while others are
dorsally ornamented (Poore, 1984, 1985).
Arcturoids may be tuberculate or spinose, and
sculpture may indicate generic relationships
(Brandt, 1990). Only two characters were
found to be informative. The sculpture of
members of the Antarcturus-group is strongly
spinose, with at least dorsal and dorsolateral
pairs of spines, often dominated by a larger
pair near the end of the pleotelson (character
8, state 1; Fig. 1g). This pattern is found in
various forms among the genera included
here in the antarcturids (Brandt, 1990). If it
is assumed that this is a synapomorphy of this
group of genera, some reduction in spination
must be accepted in genera such as Cylin-
drarcturus. However, none of the potential
sister taxa have this type of ornamentation.
The following character contrasts.
The pleotelson of arcturoids usually ends
in a distal acute apex, and if otherwise orna-
mented, bears pairs of tubercles or spines.
Austrarcturellidae (Poore and Bardsley, 1992)
and Dolichiscus (Poore, 1998) share a unique
condition in which the pleotelson bears dor-
solateral ridges ending in middorsal posterior
spine above the apex (character 9, state 1; Fig.
1e). The pattern, especially the degree of
spination, is variable, and the pleotelson was
referred to as “boat-shaped” by Poore and
Bardsley (1992).
Lateral extensions of the terga or of the
coxae over the bases of the pereiopods and of
epimera over the pleopods are typical of most
isopods. This is the situation in most idoteoids
(character 10, state 0; Fig. 1a) although there
is variation in these families between whether
the terga or the coxae are implicated (and on
what pereionites). There is also reduction of
the size of dorsal coxal plates in genera such
as Paridotea (Poore and Lew Ton, 1993). In
arcturoids, on the other hand, dorsal coxal
plates are obsolete and bases of pereiopods
are exposed (state 1; Fig. 1e–h). Here, too,
there are exceptions as in Holidotea and Aus-
troarcturus in which tergal expansions on
pereionites 2–4 reflect some idoteids (char-
acter 11, state 1; Fig. 1b). A similar conver-
gence is seen in the undoubted arcturid Arc-
turinoides (Kensley, 1977).
Mouthparts and pereiopod 1 are primitively
visible in lateral view in arcturoids (charac-
ter 12, state 0; Fig. 1g). Correlated with the
reduction of pereiopod 1 is a secondary ex-
pansion of lateral plates of head and pereion-
ite 1 so that the mouthparts and pereiopod 1
are not visible laterally (state 1; Fig. 1h).
Loss of eyes occurs frequently in Isopoda,
especially in deep-sea species and is rarely of
family value. Idoteoid valviferans are shal-
low-water species, but reduced or lost eyes is
general for Chaetiliidae (character 13, state
1; Fig. 1c). Blind valviferans occur also in arc-
turid, antarcturid, and austrarcturellid genera.
The flagellum of antenna 2 is plesiomor-
phically multiarticulate, terminating in a
simple setose article (character 14, state 0;
Fig. 1g). This is the state seen in most ido-
teoids, but three of the four genera of Holog-
nathidae and some of those of Idoteidae pos-
sess a clavate flagellum of a major and mi-
nor article (Poore and Lew Ton, 1990, 1993).
This state is not informative at the family
level. The more specialised condition where
the flagellum is of two or three articles plus
a distal curved non-setose claw (state 1; Fig.
1 e, h) is true of most arcturoids. However, the
plesiomorphic condition is seen in Antarcturus
and all similar genera, and in Dolichiscus.
The structure of mandibles and maxillae
is uninformative at the family level and rarely
so at the genus level. Valvifera are charac-
terised by absence of the mandibular palp and
this is true with only one exception. The
species Holognathus stewarti (Filhol) is
unique in the suborder in possessing a palp;
its sister species H. karamea does not (Poore
and Lew Ton, 1990). The only family in
which the mandibular molar and incisor struc-
ture varies is Chaetiliidae (Poore, 1985), but
the most plesiomorphic condition resembles
that in all other families. The maxillipedal
palp is informative at the generic level but
rarely for families. The most plesiomorphic
condition, palp of five articles, is found in
all families and is universal in arcturoids. Re-
duction in this number is usual in idoteoids,
but Poore and Lew Ton (1990, 1993) showed
212 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 21, NO. 1, 2001
that Holognathidae and Idoteidae differed in
how this fusion occurred. There are differ-
ences too between genera of Chaetiliidae. The
maxillipedal epipod is usually as long as or
longer than wide (character 15, state 0), but
in Chaetiliidae is shorter than wide. In arc-
turoids the palp is usually evenly tapering
(character 16, state 0) but in two genera, Holi-
dotea and Austroarcturus, article 3 is much
wider than article 4 (state 1; Kensley, 1975).
Typical isopods, as the name implies, have
all pereiopods much alike. In the plesiomor-
phic valviferan condition, pereiopod 1 is
slightly differentiated from pereiopod 2, its
propodus broader and with a setose mesial
face (character 17, state 0; Fig. 2a). In the
Chaetiliidae the pereiopods are variously dif-
ferentiated, the first, first three, five or six
subchelate (state 1; Fig. 2b). It is probable
that differentiation of the chaetiliid pereio-
pods is independently derived in the various
genera, but they do at least share a highly
modified pereiopod 1. In most arcturoids
pereiopod 1 is a small gnathopod (Fig. 2d),
pereiopods 2–4 are elongated and all differ-
entiated from ambulatory pereiopods 5–7
(state 3; Fig. 2f, h). Absence of pereiopods 3
and 4 was used to differentiate the species
Amesopous richardsonae at the family level
from Arcturidae (Stebbing, 1905). It and other
species lacking one or more pereiopods are
treated as derived within the Arcturus-group.
Setation of pereiopods of idoteoids is sim-
ilar to that in most other isopods, short robust
setae along the posterior margin of distal ar-
ticles with occasional longer fine setae (char-
acter 18, state 0; Fig. 2j). The long, paired,
evenly spaced filtering setae along the narrow
carpus and propodus and sometimes dacty-
lus of pereiopods 2–4 is a feature of many
arcturoids (state 1; Fig. 2h) and is usually as-
sociated with the flexed body and feeding
from the plankton. In Rectarcturus the body
is straight and filter-setae numerous, while in
Holidotea and Austroarcturus the setae are
not as regular or as numerous (state 2; Fig.
2f). In these three genera with straight bod-
ies, feeding is benthic, but it is uncertain
whether few filter-setae is an evolutionary
step that the filter-feeders went through or a
secondary reduction—probably both. In
Pseudidothea pereiopods 2–4 are raptorial
(state 3; Fig. 2g).
Aprominent dactylus and a short unguis
is the plesiomorphic condition of pereiopods
2–4 (character 19, state 0; Fig. 2f, j). Within
some arcturoids a short dactylus bearing a
longer and setiform unguis is seen (state 1; Fig.
2h). The condition is carried to extreme in Aus-
trarcturellidae where the dactylus is minute
and the unguis setiform (state 2; Fig. 2i).
Pereiopod 4 is plesiomorphically similar to
pereiopod 3 whether ambulatory or of the
elongate form (character 20, state 0; Fig. 2j).
Various autapomorphic states occur. In
Holognathidae pereiopod 4 is shorter and
more spinose than pereiopods 3 and 5 (state
1; Fig. 2k). In Austrarcturellidae it is shorter
and less setose than pereiopods 2 and 3 (state
2; Fig. 2l), and in Xenarcturus it is different
from pereiopod 3 but similar to pereiopod 5
(state 3; Sheppard, 1957).
The dactylus of pereiopod 1 is plesiomor-
phically evenly curved (character 21, state 0),
but in Dolichiscus and Austrarcturellidae it
bears an anterior lobe distinct from a taper-
ing end bearing the unguis (state 1; Fig. 2e).
The pereiopods of male isopods are rarely
different from those of females (except that
the mesial face of the propodus of pereiopod
1 is often more setose). In many sphaero-
matids and serolids, some pereiopods of
males carry a dense fur of fine setae along the
posterior margin of distal articles, the extent
of this depending on species. As these fami-
lies are probable members of the sister taxon
of Valvifera, the presence of this fur in Idote-
idae and Holognathidae is considered ple-
siomorphic (character 22, state 0; see, e.g.,
Poore and Lew Ton, 1993: Fig. 48). Absence
of this kind of male differentiation in arctur-
oids is apomorphic (state 1).
The number of uropodal rami is not use-
ful to differentiate families, two rami being
the plesiomorphic condition in all families.
Loss of the exopod occurs in two of four gen-
era of Holognathidae, all genera except
Austridotea in Idoteidae (Fig. 2p), never in
Chaetiliidae, and less frequently in arcturoids.
When present, the exopod is oval with all
margins setose in idoteoids (character 23,
state 0; Fig. 2m) but is always tapering and
with distal setae only in arcturoids (state 1;
Fig. 2n). Extreme reduction of the exopod to
a very short article bearing a single promi-
nent robust seta (the endopod also with a ro-
bust seta) is a characteristic of three genera
(character 24, state 1; Fig. 2o).
The plesiomorphic marsupium comprises
broad overlapping oostegites on pereiopods
POORE: FAMILIES OF ISOPODA VALVIFERA 213
214 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 21, NO. 1, 2001
Fig. 3. Male pleopods 1. a, Idotea (Idoteidae); b, Pseudidothea (Pseudidotheidae); c, Mixarcturus (Antarcturidae);
d, Austrarcturella (Austrarcturellidae); e, Austroarcturus (Holidoteidae) with detail; f, Astacilla (Arcturidae). Male
pleopod 2. g, Arcturopsis (Arcturidae); h, Austroarcturus (Holidoteidae); i, Chaetilia (Chaetiliidae). Penes and pe-
nial plates. j, Chaetilia (Chaetiliidae) on pereionite 7; k, Paridotea (Idoteidae); l, Austroarcturus (Holidoteidae); m,
Dolichiscus (Austrarcturellidae). Ventral views of pereionites 4 and 5 with oostegites. n, Austrarcturella (Austrarc-
turellidae) with left oostegite 4 and paired oostegites 5; o, Dolichiscus (Austrarcturellidae) with edges of oostegites
4, coxal supports and no oostegite 5.
1–5 (character 25, state 0). In highly genicu-
late species oostegites 5 cannot play a part
in holding the eggs and young so is absent
completely (state 2; Fig. 3o). Intermediate
states are found where oostegites 5 are fleshy
lobes which appear to act only as egg guides
between the oopores on pereionite 5 and the
marsupium (state 1; Fig. 3n). There is some
variability within families. Arcturus, for ex-
ample, is the only member of the Arcturus-
group with functional fifth oostegites; its ab-
sence is typical of other members of the fam-
ily where oostegite 4 dominates in formation
of the marsupium (Fig. 1h). Five pairs of
oostegites are typical of Idoteidae, but
Synidotea is unique within this family in pos-
sessing only four pairs (Poore and Lew Ton,
1993). In many arcturoids the marsupium is
supported by mesially directed extensions of
the coxal plates (character 26, state 1; Fig. 3o).
Penes are primitively paired digitiform ap-
pendages on the sternite of pereionite 7 (char-
acter 27, state 0; Fig. 3j). This condition is
seen in Chaetiliidae, but in some genera the
paired pores may open almost directly on the
sternite. In Idoteidae and Holognathidae the
penes are fused basally as a penial plate, di-
vided over most of their length and attached
on the posterior margin of pereionite 7 (state
1; Fig. 3k). In arcturoids there is a single
elongate penial plate, rarely divided apically
(state 2). This penial plate is usually simple
(Fig. 3m) or split for a short distance apically,
but in three genera it is apically bifid and
splayed (character 28, state 1; Fig. 3l).
The major dichotomy between valviferan
families is between the idoteoids, where the
pleopod 1 peduncle is short and similar to
those of pleopods 2–5 (character 29, state 0;
Fig. 3a), and arcturoids, where it is more
elongate than on other pleopods (state 1; Fig.
3b–f). Within the idoteoids, the Idoteidae dif-
fer from the others in having marginal setae
on rami of pleopod 1 much shorter than the
length of the rami (character 30, state 1; Fig.
3a), whereas setae are longer in the other fam-
ilies (state 0). The male pleopod 1 exopod is
laminar like the endopod in the Arcturus-
group (character 31, state 0; Fig. 3f) but
strongly thickened and with a groove on its
posterior face in other arcturoid families
(state 1; Fig. 3b, c, e).
The pleopod 1 exopod of males of most
arcturoids has few simple setae along a
straight lateral margin (character 32, state 0;
Fig. 3c); in the three genera that comprise the
Holidoteidae, there are complex overlapping
rows of simple and plumose setae along the
lateral margin, terminating at a subdistal ex-
cavation (state 1; Fig. 3e). The position of the
end of the groove on the posterior face of ex-
opod of pleopod 1 of males is variable and
will prove valuable in differentiating genera
in the higher arcturoids. Plesiomorphically it
ends distolaterally or laterally on a simple
margin (character 33, state 1; Fig. 3c), and
this is the condition in the Antarcturus-group.
Austroarcturus and Neoarcturus are similar
in that the groove ends in a deep subdistal ex-
cavation (state 1; Fig. 3e). In Holidotea it ends
on a distolateral rounded tip, separated from
most of lateral margin by a notch (state 2). In
austrarcturellids but not Dolichiscus, the
groove is carried on a basally derived branch
of the exopod (state 3; Fig. 3d), and in three
genera the exopod tapers to a distolateral api-
cal extension (state 4; Fig. 3b). Homologies
between the various structures involved in the
apex of the exopod are difficult to determine.
Aunique apomorphy of the Arcturus-group
is a lateral excavation on the male pleopod 1
exopod (character 34, state 1; Fig. 3f). In
many genera, but not in Arcturus, two or three
long oblique setae attach near this excavation.
The appendix masculina on pleopod 2 of
males is usually about as long as the endopod
(character 35, state 0; Fig. 3h) but can be
twice its length (state 1; Fig. 3i). The appen-
dix masculina is typically basally less than
half the width of the endopod (character 36,
state 0) but in the Arcturus-group is basally
as wide or wider than the endopod (state 1;
Fig. 3g). The nature of appendages and
grooves on the appendix masculina is useful
for diagnosing genera. For example, it is api-
cally club-shaped in Neoarcturus (character
37, state 1).
Results of Phylogenetic Analysis
The cladogram (Fig. 4a) provides a well-
resolved hypothesis about relationships be-
tween the families and genera of Valvifera.
Using unweighted and unordered characters,
six equal-length trees of 60 steps were dis-
covered. The strict consensus tree (60 steps,
CI = 0.82 excluding uninformative characters,
RI = 0.88) supported three basal clades whose
relationships were not further resolved:
Chaetiliidae; Idoteidae + Holognathidae as
sister taxa; and an arcturoid clade. The Arc-
POORE: FAMILIES OF ISOPODA VALVIFERA 215
turus-group is sister taxon to all other arc-
turoids. Within the remaining arcturoids are
two clades: Rectarcturus, sister taxon to Xe-
narcturus + Pseudidothea + Arcturides; and
a fully resolved clade comprising the re-
maining genera. Of these, Antarcturus is sis-
ter taxon to the rest, one clade comprising
Dolichiscus + Austrarcturellidae and another
Neoarcturus + Austroarcturus + Holidotea.
The clades of the bootstrap analysis are not
as well resolved (Fig. 4b). Bootstrap values
varied ±2% over four Paup* runs.
The 60 synapomorphies of the clades in
Fig. 4a are listed in Table 3 and discussed
below. Family autapomorphies are considered
in the Systematics section.
Idoteidae + Holognathidae (clade-16), with
78% bootstrap support, share: at least
pleonites 1–3 articulating with each other and
fused pleotelson; and a fused penial plate di-
vided over most of its length.
The arcturoids (clade-25), with 100% boot-
strap support, are well defined by 11 synapo-
morphies, as follows: dorsal coxal plates 2–7
obsolete, bases of pereiopods exposed later-
ally (body usually cylindrical); pereiopods
differentiated, pereiopod 1 a gnathopod,
pereiopods 2–4 usually with paired long se-
tae along posterior margins, and pereiopods
5–7 ambulatory; pereiopods of males with a
dense fur of fine setae on some articles; head
and pereionite 1 fused; all pleonites fused into
pleotelson (rarely reversed); antenna 2 fla-
gellum of 2 or 3 articles plus distal claw
(sometimes multiarticulate); uropodal exopod
tapering (with terminal setae only); a fully
fused penial plate; and pleopod 1 peduncle
more elongate than on other pleopods.
Clade-24, containing all the arcturoids ex-
cept the Arcturus-group, has 70% bootstrap
support and two synapomorphies: oostegites
5 absent, and the exopod of the male pleo-
pod 1 thickened and with a groove on its pos-
terior face. A reversal to oostegites 5 being
present as vestigial lobes seems probable for
some genus-groups.
Clades-21 and 20 (not supported by the
bootstrap analysis) have one synapomorphy
216 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 21, NO. 1, 2001
Fig. 4. Cladograms depicting relationships between families, genus-groups, and genera of Valvifera derived by
Paup*. a, strict consensus tree, clade lengths (numbered as in Table 3) are proportional to the numbers of steps sup-
porting them; b, 50% majority rule consensus tree from bootstrap analysis, clade lengths are proportional to boot-
strap values. Both trees are rooted against a hypothetical ancestor.
each: oostegites supported by coxal lobes, and
pereiopods 2–4 with short dactylus respec-
tively.
Clade-18 (Neoarcturus + Austroarcturus +
Holidotea), with 91% bootstrap support, is
well defined by four synapomorphies, all with
CI = 1: uropod exopod very short, both rami
each bearing a single, prominent robust seta;
penial plate apically bifid and splayed; pleo-
pod 1 exopod of male with overlapping rows
of simple and plumose setae along lateral
margin, terminating at subdistal excavation,
and with its groove ending in deep subdistal
excavation.
The original Austrarcturellidae plus
Dolichiscus (clade-19), with 76% bootstrap
support, is defined by two synapomorphies,
each with CI = 1: pleotelson with dorsolat-
eral ridges usually ending in middorsal pos-
terior spine; and pereiopod 1 dactylus usually
with an anterior lobe.
Clade-23, without bootstrap support, de-
pends on a reversal from a flexed to a straight
body retaining differentiated setose pereiopods
2–4 while pereiopods 5–7 are ambulatory.
Finally, clade-22 (Xenarcturus + Pseudi-
dothea + Arcturides), also without bootstrap
support, shares one unique synapomorphy:
pleopod 1 of male with the groove on the pos-
terior face of exopod ending on tapering dis-
tolateral apical extension.
Comparison with Other Views
Sheppard (1957) discussed the similarities
between some families and genera of Val-
vifera but did not propose a phylogeny. She
interpreted the structure of coxae, oostegites,
and penial processes. Recent views of the
phylogeny of the Valvifera suffer from a nar-
row view of the Holognathidae (one species
with a mandibular palp) now shown to be re-
strictive (Poore and Lew Ton, 1990). Brusca
(1984) (reported as the traditional system by
Wägele (1989)) treated the Holognathidae as
sister taxon to all other families that lack a
mandibular palp. This observation is no
longer true if the expanded Holognathidae is
accepted (Poore and Lew Ton, 1990).
Brusca’s cladogram is a very different view
of valviferan relationships from that presented
here. He treated Idoteinae and the “glyptono-
tine-group” (= Chaetiliidae) as sister taxa of
Idoteidae sharing reduced maxillipedal palp.
It is true that some genera of the three fam-
ilies Idoteidae, Chaetiliidae, and Holognathi-
dae have fewer than five articles in the max-
illipedal palp and that this never happens in
the arcturoids. However, the most ple-
siomorphic condition (five articles) occurs in
all three families, and this is not a character
in my analysis. The propensity to fuse arti-
cles is a synapomorphy of the idoteoid fam-
ilies, but fusion itself is not. Brusca recog-
nised the monophyly of the arcturoids shar-
ing a copulatory function for the male
pleopod 1, fusion of the head with pereion-
ite 1, and elongation of the peduncle of pleo-
pod 1. However, there is no similarity be-
tween his cladogram relating the four arctur-
oid families he recognised and the one
presented here.
Wägele’s (1989: Fig. 63) treatment of the
idoteoids maintained the ancestry of Holo-
gnathus and placed the Chaetiliidae as sister
taxon to Idoteidae (including most Holo-
gnathidae) plus arcturoids, very different from
my analysis. His treatment of Arcturidae
(= arcturoids) (1989: Fig. 67, 68) recognised
four subfamilies. Three of these are smaller
groups more or less similar to the families
POORE: FAMILIES OF ISOPODA VALVIFERA 217
Table 3. Synapomorphies of each clade and taxon in the
strict consensus cladogram generated by PAUP* (Fig. 4a).
Unannotated characters change from state 0 to state 1, a
minus sign indicates a reversal from 1 to 0, and super-
scripts other changes from 0 or another state to a sec-
ond.
Clade number or taxon Characters changing
clade-16 6, 27
Holognathidae 2, 20
Idoteidae 6
1>2
, 30
Chaetiliidae 4, 13, 15, 17, 35
clade-25 12
2
, 3, 6
4
, 10, 14, 17
2
, 18,
22, 23, 27
2
, 29
Arcturus-group 5, 12, 34, 36
clade-24 25
2
, 31
clade-21 26
clade-20 19
clade-18 24, 28, 32, 33
clade-17 1
2>1
, 11, 16, 18
1>2
Austroarcturus 6
4>3
Holidotea 33
1>2
Neoarcturus 37
clade-19 9, 21
Dolichiscus 6
4>3
, 7, –14
Austrarcturellidae 19
1>2
, 20
2
, 25
2>1
, 33
3
, 35
Antarcturus-group 8, –14
clade-23 1
2>1
Rectarcturus 19
clade-22 33
4
Xenarcturus 20
3
Pseudidothea 18
1>3
Arcturides –18, 26
recognised here: Holidoteinae (to which I add
another genus), Pseudidotheinae (from which
I separate Arcturides), and monotypic Xe-
narcturinae. His cladogram of Arcturinae was
weakly resolved but recognised the similar-
ity between Pseudarcturella and Dolichiscus
(now Austrarcturellidae) and the monophyly
of the Acturina-Parastacilla-Astacilla-group,
which share an elongated pereionite 4. This
last group I call the Arcturidae, sensu stricto,
and place as sister taxon to all other arctur-
oids, a different scheme from that of Wägele.
My new phylogeny places Arcturus and
Antarcturus in very different families (see,
too, Nordenstam (1933)); Wägele (1989) sug-
gested that they possibly shared a secondar-
ily elongated antenna 2 with multiarticulate
flagellum.
SYSTEMATICS
Nomenclatural implications that flow from
this analysis are influenced by the retention
of existing family-level names. Thus, Idotei-
dae, Holognathidae, and Chaetiliidae remain
as recently treated by most authors. Arcturi-
dae, which until now included most of the
remaining valviferan genera, is here confined
to the smaller Arcturus-group. Wägele’s
(1989) Holidoteinae, erected for Austroarc-
turus and Holidotea must be expanded to in-
clude Neoarcturus and elevated to full fam-
ily rank. The Austrarcturellidae is expanded
to include Dolichiscus which is clearly more
similar to this group of genera than to any
other. Xenarcturus is the only genus in Xe-
narcturidae, and Pseudidothea is the only one
in Pseudidotheidae. The two are similar to
Arcturides, but none of the phylogenetic hy-
potheses provides good support for includ-
ing this genus in either family. I propose a
third family, Arcturididae, for it.
The Antarcturus-group and Rectarcturus
clades remain independent of all others, and
new families are proposed for each, Antarc-
turidae and Rectarcturidae.
The characters and states used for the phy-
logenetic analysis were used for preparing a
character file for DELTA treatment (Dallwitz
et al., 1997). The number of taxa was reduced
from 14 to 11, the number of families recog-
nised, and some characters appropriately
edited to accommodate this change. Diag-
noses were prepared directly; there are no im-
plicit characters. The order of the families in
the following text follows that in the key.
Suborder Valvifera Sars, 1882
Diagnosis.—Isopoda with uropods attached
laterally to pleotelson, folding under and en-
closing pleopods. Pleonite 5 (and often oth-
ers) fused with pleotelson. Mandibular palp
absent (1 exception).
Remarks.—One unique synapomorphy de-
fines all Valvifera, the way in which the uro-
pod is rotated and folded under the pleotel-
son to enclose the pleopods in a branchial
chamber. The uropods are posterior, lateral,
and styliform or flattened in other suborders.
Branchial chambers are found in other sub-
orders but are variously formed by operculi-
form pleopods. A second character involves
pleonites. Some pleonites are often fused with
the pleotelson, sometimes all pleonites, but
the most plesiomorphic condition is fusion of
pleonite 5 with the pleotelson. Pleonite fusion
is seen to various degrees in other suborders.
Athird character state, absence of the
mandibular palp, is a synapomorphy seen in
many other isopods. There is only one val-
viferan species (Holognathus stewarti) out of
more than 500 described carrying a palp, and
this is certainly a reversal of the subordinal
synapomorphic state (Poore and Lew Ton,
1990).
Areview of the systematics and phylogeny
of the group (Brusca, 1984) recognised six
families (one, the Idoteidae with five sub-
families) but recent revisions (Wägele, 1989;
Poore and Lew Ton, 1990, 1993; Poore and
Bardsley, 1992) suggested that his was not a
satisfactory taxonomic arrangement.
KEY TO FAMILIES OF VALVIFERA
1. Head free from pereionite 1 (rarely fused) (Fig. 1a,
b, d); pereiopod 1 subchelate and similar to (Fig.
2a) or larger than pereiopod 2 (Fig. 2b); pleopod 1
peduncle not elongate (Fig. 3a); with separate penes
or penial plate fused only basally . . . . . . . . . . . 2
Head fused with pereionite 1 (Fig. 1e–h); pereio-
pod 1 smaller than pereiopod 2, sometimes gnatho-
pod-like, very different in structure from pereiopod
2 (Fig. 2c, d); pleopod 1 peduncle elongate (Fig.
3b–f); with penial plate bifid apically if at all . . . 4
2. Pereiopods 1, 1–3, 1–5 or 1–6 subchelate or pre-
hensile (Fig. 1b) and different from remaining limbs;
head with flat lateral lobes, sometimes notched (Fig.
1c); uropod with 2 rami (Fig. 2m) . . . Chaetiliidae
Only pereiopod 1 subchelate (Fig. 2a), others am-
bulatory; head without flat lateral lobes, never
deeply notched (Fig. 1d); uropod with 1 (Fig. 2m)
or 2 rami . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Pereiopod 4 similar to other pereiopods (Fig. 2j);
body oval or elongate; pleotelson posteriorly acute,
rarely rounded . . . . . . . . . . . . . . . . . . . Idoteidae
218 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 21, NO. 1, 2001
Pereiopod 4 shorter than others and with spinose
distal articles (Fig. 2k); body more or less parallel-
sided; pleotelson posteriorly rounded (Fig. 1d) . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . Holognathidae
4. Pereiopod 1 coxal plate and head expanded ven-
trally (Fig. 1h) and enclosing gnathopod-like pereio-
pod 1 (Fig. 2d); male pleopod 1 exopod laminar,
with lateral notch, a tuft of fine setae, 2 or 3 long
plumose setae, or a combination of these (Fig. 3f)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . Arcturidae
Pereiopod 1 coxal plate not expanded to enclose
pereiopod 1 (Fig. 1g); pereiopod 1 a grasping limb
(Fig. 2c); male pleopod 1 exopod thickened, with
groove (Fig. 3b, c, e) or with lateral secondary
ramus (Fig. 3d) . . . . . . . . . . . . . . . . . . . . . . . . 5
5. Uropodal rami each with apical strong robust seta,
exopod minute, shorter than wide (Fig. 2o); pe-
nial plate apically bifid and splayed (Fig. 3l); exo-
pod of male pleopod 1 with overlapping rows of
simple and plumose setae along lateral margin, ter-
minating at subdistal excavation into which groove
opens (Fig. 3e); body cylindrical or often flattened
(Fig. 1b) . . . . . . . . . . . . . . . . . . . . . Holidoteidae
Uropodal rami, if present, without apical strong ro-
bust seta, exopod longer than wide, usually with 2
or 3 long apical setae (Fig. 2n); penial plate apically
simple or weakly bifid (Fig. 3m); exopod of male
pleopod 1 with simple row of setae along lateral mar-
gin; groove opens distolaterally or laterally (Fig. 3c);
body cylindrical or rarely flattened (Fig. 1e–h) . . . 6
6. Body strongly geniculate between pereionites 4
and 5 (Fig. 1e, g, h) . . . . . . . . . . . . . . . . . . . . 7
Body straight, not flexed between pereionites 4 and
5 (Fig. 1f) . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
7. Pleotelson variously sculptured, often with paired
posterior pleotelsonic spines (Fig. 1g), but without
single medial posterior spine dorsal to apex;
pereiopods 2–4 with dactylus strong, unguis short
(rarely setiform) (Fig. 2h); pereiopods 2–4 simi-
lar; pleonite 1 not articulating with pleotelson;
groove on exopod of male pleopod 1 opening dis-
tolaterally or laterally . . . . . . . . . . Antarcturidae
Pleotelson with dorsolateral ridges usually ending
in middorsal posterior spine dorsal to apex (or
transverse ridge of spines) (Fig. 1e); pereiopods
2–4 with dactylus shortened, unguis setiform,
longer than dactylus (Fig. 2i); pereiopod 4 usually
smaller and less setose than pereiopods 2 and 3
(Fig. 2l); pleonite 1 weakly or not articulating with
pleotelson; groove on exopod of male pleopod 1
opening distolaterally or exopod with prominent
basally derived lateral lobe . . . . Austrarcturellidae
8. Body dorsoventrally flattened, dorsally setose, with-
out spines; pereiopods 2 and 3 with even rows of long
setae, pereiopods 4–7 ambulatory . . . Xenarcturidae
Body cylindrical, ornamented; pereiopods 2–4 dif-
ferentiated from ambulatory pereiopods 5–7 or
pereiopods 2–7 ambulatory . . . . . . . . . . . . . . . 9
9. Pereionites cylindrical, longer than wide, each with
paired simple dorsal spines; pereiopods 2–7 similar,
ambulatory . . . . . . . . . . . . . . . . . . . . Arcturididae
Pereionites wider than long, with complex dorsal
plate-like spination (Fig. 1f); pereiopods 2–4 dif-
ferentiated from ambulatory pereiopods 5–7 . . . 10
10. Pereiopods 1–4 with strong robust setae on broad ar-
ticles, dactyli with short unguis (Fig. 2g); exopod of
male pleopod 1 with groove ending on curved disto-
lateral apical extension (Fig. 3b) . . Pseudidotheidae
Pereiopods 2–4 with weak rows of long setae,
dactyli with long, setiform unguis; exopod of male
pleopod 1 with groove ending distolaterally (Fig.
3c) . . . . . . . . . . . . . . . . . . . . . . . Rectarcturidae
Chaetiliidae Dana, 1853
Chaetiliidae Dana, 1853: 711.—Poore, 1985: 154 (syn-
onymy).
Diagnosis.—Body straight, more or less flat-
tened or semicylindrical, or strongly vaulted;
tapering posteriorly. Head and pereionite 1
free. Head with prominent flat lateral lobes,
sometimes with ocular notch. Pereionite 4 of
similar length to pereionite 3. Pleonites 1–4
articulating with each other and fused pleo-
telson, or pleonites 1–3 articulating with each
other and fused pleotelson, or pleonites 1 and
2 articulating with each other and fused pleo-
telson (other pleonites sometimes indicated
laterally or dorsally). Body smooth or slightly
sculptured, or variously spinose or rugose.
Dorsal coxal plates 2–7 more or less ventrally
expanded over bases of pereiopods, or 5–7
expanded over bases of pereiopods and ter-
gites marginal on pereionites 2–4. Eyes re-
duced or lost.
Antenna 2 flagellum multiarticulate (some-
times of few articles). Maxillipedal epipod
shorter than wide. Pereiopods differentiated,
1, 1–3, 1–5, or 1–6 subchelate. Pereiopods
2–4 with irregular fine setae and marginal ro-
bust setae. Pereiopods of males without dense
fur of fine setae. Uropodal exopod (smaller
ramus) ovate, fringed with setae (if present),
more than half as long as endopod, or rami
styliform.
Oostegites 1–5 functional (as far as
known). Penes paired, widely separate (some-
times obsolete). Pleopod 1 peduncle short
(similar to other pleopods); with marginal se-
tae on rami longer than or equal to length of
rami. Pleopod 1 exopod of male laminar.
Pleopod 2 of male with appendix masculina
twice length of endopod, basally less than
half width of endopod.
Included Genera (with numbers of described
species).—Austrochaetilia Poore, 1978 (1);
Chaetilia Dana, 1849 (4); Chiridotea Harger,
1878 (6); Glyptonotus Eights, 1852 (1);
Macrochiridothea Ohlin, 1901 (11); Maori-
dotea Jones and Fenwick, 1978 (1);
Parachiridotea Daguerre de Hureaux and
Elkaïm, 1972 (1); *Proidotea Racovitza and
Sevastos, 1910 (1); Saduria Adams, 1852 (4);
Saduriella Holthuis, 1964 (1); Stegidotea
POORE: FAMILIES OF ISOPODA VALVIFERA 219
Poore, 1985 (6); Symmius Richardson, 1904
(3) (40 species in all).
Remarks.—Several synapomorphies define
the Chaetiliidae. The flattened shape relative
to idoteids is reliable for some genera,
whereas others are quite deep. All have lat-
eral lobes on the head. The eyes are often lost
and never as well developed as in Idoteidae
or Holognathidae. The presence of subchelate
limbs is regarded as synapomorphic, but the
number and shape of the prehensile propo-
dus and dactylus do vary between genera. As
far as is known the appendix masculina is
much longer than the endopod of pleopod 2.
Poore (1984) listed the genera then known
as “non-idoteine Idoteidae” but mistakenly in-
cluded Austridotea and Notidotea, treated as
synonymous and idoteids here. Later, I re-
viewed the status of the family, synonymis-
ing the five subfamilies of Idoteidae, which
it comprises (Poore, 1985). Wägele (1989:
Fig. 62) presented a dendrogram and discus-
sion of the genera.
Members of the Chaetiliidae are marine
benthic species of sandy beaches, shelf or
deep-sea environments. The family includes
the only known valviferan fossil species,
Proidotea haugi.
Holognathidae Thomson, 1904
Holognathidae Thomson, 1904: 67.—Poore and Lew Ton,
1990: 58.
Diagnosis.—Body straight, more or less flat-
tened or semicylindrical; parallel-sided over
most of length. Head and pereionite 1 free.
Head more or less semi-cylindrical. Pereion-
ite 4 of similar length to pereionite 3. Pleo-
nites 1–3 articulating with each other and
fused pleotelson, or pleonites 1 and 2 articu-
lating with each other and fused pleotelson,
or pleonite 1 articulating with fused pleotel-
son (other pleonites sometimes indicated lat-
erally or dorsally). Body smooth or slightly
sculptured. Dorsal coxal plates 2–7 more or
less ventrally expanded over bases of
pereiopods. Eyes well developed, or reduced
or lost (Zenobianopsis only).
Antenna 2 flagellum multiarticulate, or
clavate (usually with minute terminal arti-
cle(s)). Maxillipedal epipod as long as or
longer than wide. Pereiopod 1 slightly dif-
ferentiated from pereiopod 2, its propodus
broader than in pereiopod 2. Pereiopods 2–4
with irregular fine setae and marginal robust
setae; with prominent dactylus, unguis short;
pereiopod 4 shorter and more spinose than
pereiopods 3 and 5. Pereiopods of males with
dense fur of fine setae. Uropodal exopod
(smaller ramus) ovate, fringed with setae (if
present), more than half as long as endopod.
Oostegites 1–5 functional. Penes fused
basally as a penial plate but divided over most
of length. Pleopod 1 peduncle short (similar
to other pleopods); with marginal setae on
rami longer than or equal to length of rami.
Pleopod 1 exopod of male laminar. Pleopod
2 of male with appendix masculina about as
long as endopod, basally less than half width
of endopod.
Included Genera (with numbers of described
species).—Cleantioides Kensley and Kauf-
man, 1978 (13); Cleantis Dana, 1849 (8);
Holognathus Thomson, 1904 (2); Zeno-
bianopsis Hale, 1946 (2) (25 species total).
Remarks.—Poore and Lew Ton (1990) re-
moved genera from the Idoteidae and grouped
them on the basis of body-plan and specialised
pereiopod 4, synapomorphies of the family.
They provided a key to genera and listed all
species. This is the only family in which a
species with a mandibular palp is found.
Shallow-water species of Cleantis and
Cleantioides are often associated with sea-
grasses and live in short segments of the dead
hollow stems of these plants. Holognathus
from the shelf of New Zealand is thought to
be associated with wood. Zenobianopsis is a
deep-water Antarctic genus.
Idoteidae Samouelle, 1819
Idoteadae Samouelle, 1819: 106.
Idoteidae.—Kussakin, 1982: 71, 72.—Brusca, 1984: 106
(for synonymy).—Poore and Lew Ton, 1993: 199.
Diagnosis.—Body straight, more or less flat-
tened or semicylindrical, or strongly vaulted;
tapering posteriorly. Head and pereionite 1
free, or fused (Crabyzos, Lyidotea only).
Head more or less semicylindrical. Pereion-
ite 4 of similar length to pereionite 3.
Pleonites 1 and 2 articulating with each other
and fused pleotelson, or pleonite 1 articulat-
ing with fused pleotelson, or all pleonites
fused into pleotelson (other pleonites some-
times indicated laterally or dorsally). Body
smooth or slightly sculptured, or variously
spinose or rugose. Dorsal coxal plates 2–7
more or less ventrally expanded over bases of
220 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 21, NO. 1, 2001
pereiopods (coxal plates often very reduced),
or 5–7 expanded over bases of pereiopods and
tergites marginal on pereionites 2–4 (Syni-
dotea only), or 2–7 obsolete and with ex-
panded marginal tergites (Synischia only).
Eyes well developed, or reduced or lost.
Antenna 2 flagellum multiarticulate, or
clavate (usually with minute terminal arti-
cle(s)). Maxillipedal epipod as long as or
longer than wide. Pereiopod 1 slightly dif-
ferentiated from pereiopod 2, its propodus
broader than in pereiopod 2. Pereiopods 2–4
with irregular fine setae and marginal robust
setae; with prominent dactylus, unguis short;
pereiopod 4 similar to pereiopod 3. Pereio-
pods of males with dense fur of fine setae.
Uropodal exopod (smaller ramus) ovate,
fringed with setae (if present) (usually ab-
sent), more than half as long as endopod.
Oostegites 1–5 functional, or 1–4 func-
tional, 5 absent (Synidotea only). Penes fused
basally as a penial plate but divided over most
of length, or fused as a single penial plate
(Synidotea only), or paired, elongate (Lyi-
dotea only). Pleopod 1 peduncle short (sim-
ilar to other pleopods); with marginal setae
on rami much shorter than length of rami.
Pleopod 1 exopod of male laminar. Pleopod
2 of male with appendix masculina about as
long as endopod, basally less than half width
of endopod.
Included Genera (with numbers of described
species).—Austridotea, new genus (4); Bate-
dotea Poore and Lew Ton, 1993 (1);
Cleantiella Richardson, 1912 (2); Colidotea
Richardson, 1899 (4); Crabyzos Bate, 1863
(1); Edotia Guérin-Méneville, 1843 (18); En-
gidotea Barnard, 1914a (2); Erichsonella
Benedict, 1901 (7); Euidotea Collinge, 1917a
(8); Eusymmerus Richardson, 1899, new
combination (2); Glyptidotea Stebbing, 1902
(1); Idotea Fabricius, 1798 (27); Lyidotea
Hale, 1929 (1); Moplisa Moreira, 1974 (1);
Parasymmerus Brusca and Wallerstein, 1979
(1); Paridotea Stebbing, 1900 (13); Pentias
Richardson, 1904 (3); Pentidotea Richardson,
1905 (11); Platidotea Park and Wägele, 1995
(1); Synidotea Harger, 1878 (56); Synischia
Hale, 1924 (2); Synisoma Collinge, 1917b
(10) (176 species in all).
Remarks.—One genus name, Austridotea,
nomen nudum, is formalised here with a short
diagnosis. Its four species have been enig-
matic, but a close comparison of abundant
material of A. lacustris with Idotea discov-
ered few generic differences. The most criti-
cal is the presence of two uropodal rami,
making it the only idoteid genus to possess a
uropodal exopod. In this and the presence of
two free pleonites, it is the most plesiomor-
phic of idoteid genera.
The genus Ronalea Menzies and Bowman,
1956, is proposed as a junior synonym of Eu-
symmerus. Both share a tubercle on the head,
similar maxilliped, and pleotelson. The only
difference between the two species involved,
in the shape of the coxae, is trivial.
The only identifiable synapomorphy of the
family is the presence of short setae on the
margins of the pleopods. All genera except
Austridotea lack a uropodal exopod. The
largest genus, Synidotea, differs from all the
others in possession of a completely fused
short penial plate, only four pairs of ooste-
gites, and sexually dimorphic mouthparts.
Brusca (1984) discussed the phylogeny of
the Idoteidae and Holognathidae together (as
Idoteinae), and his work is a key source for
identification of some genera and for bio-
geography. Wägele’s (1989: Fig. 63) dendro-
gram and discussion did not resolve rela-
tionships between the genera. Poore and Lew
Ton (1993) reinterpreted the structure of the
pleon, a traditional character, and provided
keys to the Australian and New Zealand
species. It is probable that many species of
Idotea, especially those with fused pleonites,
do not belong to this genus.
Idoteids are shallow water species, and in
Australia few species are found below 20 m
depth. Most are associated with seagrass and
algae and are probably herbivores. Diversity
is highest in temperate waters of the South-
ern Hemisphere, and the most plesiomorphic
genus, Austridotea, is confined to freshwater
streams of southern New Zealand. Only the
largest genus, Synidotea, is rich in species in
the Northern Hemisphere.
Austridotea,new genus
Austridotea Nicholls, 1937: 115–118.—Hurley, 1961: 265
(nomen nudum).
Austridotea (Austridotea) Nicholls, 1937: 118 (nomen
nudum).
Austridotea (Notidotea) Nicholls, 1937: 126–128 (nomen
nudum).
Notidothea.—Nierstrasz, 1941: 280.
Notidotea.—Hurley, 1961: 266.
POORE: FAMILIES OF ISOPODA VALVIFERA 221
Type Species.—Idotea lacustris Thomson,
1879.
Diagnosis.—Pleon with 2 freely articulating,
full-width pleonites and pleotelson, with 1 or
2 pleonites indicated laterally by partial su-
ture. Antenna 1 flagellum of 1 clavate article.
Antenna 2 flagellum multiarticulate. Maxil-
lipedal palp with 5 articles, or articles 4 + 5
fused. Uropod with free exopod and endopod.
Remarks.—Nicholls (1937) proposed the
generic name Austridotea, with subgenera
Austridotea and Notidotea, for three species
from New Zealand and one from southern
South America without designating a type
species. The genus-level names are therefore
nomina nuda (ICZN Article 13(b)). This con-
tribution makes Austridotea available. The
genus has sometimes been treated as a mem-
ber of the Chaetiliidae (Poore, 1991a) on the
basis of the slightly flattened habitus, free
pleonites, and possession of two uropodal
rami. However, the pereiopods, mouthparts,
and general body proportions of two species
examined (A. lacustris (Thomson, 1879) and
A. benhami Nicholls, 1937) are so similar to
species of Idotea that it is impossible to place
them in another family. Austridotea and
Idotea are the only two idoteid genera with
truly articulating pleonites (Poore and Lew
Ton, 1993). The only substantial difference
between them is the uropodal rami, two in the
former rather than one as is the case in all
other members of Idoteidae.
Arcturidae Bate and Westwood, 1868,
new combination
Arcturidae Bate and Westwood, 1868: 359, 360.—Kens-
ley, 1978a: 16, 17 (part).—Kensley and Schotte, 1989:
252 (part).—Kussakin, 1982: 270–272 (part).
Arcturinae.—Wägele, 1989: 138.—Wägele, 1991: 88
(part).
Amesopodidae Stebbing, 1905: 44.
Diagnosis.—Body flexed between pereionites
4 and 5, or strongly geniculate between
pereionites 4 and 5 (especially in male), or
straight, more or less flattened or semicylin-
drical (Arcturinoides only). Head and
pereionite 1 fused. Pereionite 4 at least 1.5
times as long as pereionite 3 (in males often
much longer). All pleonites fused into pleo-
telson. Body smooth or slightly sculptured, or
variously spinose or rugose; pleotelson with-
out dorsolateral ridges ending in mediodor-
sal posterior spine. Dorsal coxal plates 2–7
obsolete, bases of pereiopods exposed, or 2–7
obsolete and with expanded marginal tergites
(Arcturinoides only). Mouthparts and pereio-
pod 1 enclosed in lateral view by lateral plates
of head and pereionite 1. Eyes well devel-
oped, or reduced or lost (rare).
Antenna 2 flagellum of 2 or 3 articles plus
distal claw. Pereiopod 1 a gnathopod, pereio-
pods 2–4 elongated, differentiated from am-
bulatory pereiopods 5–7 (some of pereiopods
2–4 rarely absent). Pereiopod 1 dactylus
evenly curved along anterior margin, evenly
tapering if present. Pereiopods 2–4 with
paired long setae along posterior margins
evenly and well developed; with prominent
dactylus, unguis short (or dactylus lost in
some pereiopods); pereiopod 4 similar to
pereiopod 3. Pereiopods of males without
dense fur of fine setae. Uropodal exopod
(smaller ramus) tapering (with terminal se-
tae only), more than half as long as endopod
(usually).
Oostegites 1–4 functional, 5 absent, or 1–5
functional (Arcturus only); oostegites 1–4 not
supported by coxal lobes. Penes fused as a
single penial plate; penial plate apically
simple or barely slit. Pleopod 1 peduncle
more elongate than on other pleopods; with
marginal setae on rami longer than or equal
to length of rami. Pleopod 1 exopod of male
laminar; with lateral excavation. Pleopod 2 of
male with appendix masculina about as long
as endopod (or longer), basally as wide or
wider than endopod.
Included Genera (with numbers of described
species).—Agularcturus Kensley, 1984 (1);
Amesopous Stebbing, 1905 (1); Arctopsis
Barnard, 1920 (1); Arcturella Sars, 1897 (15);
Arcturina Koehler, 1911 (5); Arcturinella
Poisson and Maury, 1931 (1); Arcturinoides
Kensley, 1977 (2); Arcturopsis Koehler, 1911
(3); Arcturus Latreille, 1829 (24); Astacilla
Cordiner, 1793 (27); Edwinjoycea Menzies
and Kruczynski, 1983 (1); Idarcturus
Barnard, 1914b (3); Neastacilla Tattersall,
1921 (35); Parastacilla Hale, 1946 (2); Para-
pleuroprion Kussakin, 1972 (1); Spectarc-
turus Schultz, 1981 (1) (123 described species
in all).
Remarks.—As now confined, the Arcturidae
possess an exopod on male pleopod 1 with a
lateral notch, and either a tuft of fine setae,
222 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 21, NO. 1, 2001
2 or 3 long plumose setae, or a combination
of these. The appendix masculina is undi-
vided, bifid, or trifid. Amesopodidae are the
same and very different from the situation in
the antarcturid-like families. Pereiopod 1 is
very small, one of the mouthparts, and en-
closed by lateral plates of the first coxae.
Pereiopods 2–4 have long setae and interlock
closely against the ventral body. Pereionite 4
may be exceptionally elongate in one or both
sexes but this is not universal. A similar con-
dition never occurs in the Antarcturidae, the
new family erected here to receive non-con-
forming genera. The two species of Arcturi-
noides are exceptional in adopting a limpet-
like habitus while retaining all important fea-
tures of the family. Arcturus is the least
apomorphic genus, with five pairs of ooste-
gites and a barely flexed body.
The Amesopodidae (only species, Ameso-
pous richardsonae) differ from most arcturids
in the absence of pereiopods 2 and 3. Another
similar species, Edwinjoycea horologium
Menzies and Kruczynski, 1983, has a single-
articled pereiopod 2 and lacks pereiopods 3
and 4 (Müller, 1993). Müller erected the sub-
family Edwinjoycinae [sic] to accommodate
this species. The two species of Arturinoides
lack pereiopod 4. Loss of distal articles of
pereiopods 1–4 is common in the family. All
three genera are otherwise similar to
Neastacilla. The Amesopodidae and Edwin-
joyceinae, both representing single species,
cannot be recognised as valid taxa within the
Arcturidae. All other species comprise a para-
phyletic or polyphyletic group.
This use of Arcturidae is not equivalent to
Wägele’s (1989) Arcturinae which included
these genera and others here assigned to
Antarcturidae and Austrarcturellidae.
The family is globally widespread in shal-
low and shelf depths, especially in cooler
waters.
Holidoteidae Wägele, 1989
Holidoteinae Wägele, 1989: 137.
Diagnosis.—Body straight, more or less flat-
tened or semicylindrical, or flexed between
pereionites 4 and 5. Head and pereionite 1
fused. Pereionite 4 of similar length to
pereionite 3. All pleonites fused into pleotel-
son, or pleonite 1 articulating with fused pleo-
telson (weakly). Body smooth or slightly
sculptured, or variously spinose or rugose;
pleotelson without dorsolateral ridges ending
in mediodorsal posterior spine. Dorsal coxal
plates 2–7 obsolete, bases of pereiopods ex-
posed, or 2–7 obsolete and with expanded
marginal tergites (females only). Mouthparts
and pereiopod 1 visible in lateral view (may
be hidden by expanded tergites). Eyes well
developed, or reduced or lost (rare).
Antenna 2 flagellum of 2 or 3 articles plus
distal claw. Pereiopod 1 a gnathopod, pereio-
pods 2–4 elongated, differentiated from am-
bulatory pereiopods 5–7. Pereiopod 1 dactylus
evenly curved along anterior margin, evenly
tapering. Pereiopods 2–4 with scattered and
uneven long setae along posterior margins;
with short dactylus, unguis longer and seti-
form; pereiopod 4 similar to pereiopod 3.
Pereiopods of males without dense fur of fine
setae. Uropodal exopod very short, bearing a
single prominent robust seta, endopod also
with robust apical seta.
Oostegites 1–4 functional, 5 absent; ooste-
gites 1–4 supported by coxal lobes. Penes
fused as a single penial plate; penial plate api-
cally bifid and splayed. Pleopod 1 peduncle
more elongate than on other pleopods; with
marginal setae on rami longer than or equal
to length of rami. Pleopod 1 exopod of male
thickened and with groove on posterior face,
with overlapping rows of simple and plumose
setae along lateral margin, terminating at sub-
distal excavation; with groove on posterior
face of exopod ending on distolateral lobed
tip, separated from most of lateral margin by
notch. Pleopod 2 of male with appendix mas-
culina about as long as endopod, basally less
than half width of endopod.
Included Genera (with numbers of described
species).—Austroarcturus Kensley, 1975 (6);
Holidotea Barnard, 1920 (1); Neoarcturus
Barnard, 1914a (9) (16 species in all).
Remarks.—Austroarcturus, Holidotea and
Neoarcturus (all southern African) share three
important characteristics, synapomorphies
uniting them as a family. The penial plate is
apically bifid and splayed; both uropodal rami
are present and possess a robust terminal seta,
microscopically serrate (the exopod is shorter
than wide); and the exopod of the male pleo-
pod 1 has overlapping rows of simple and
plumose setae along its lateral margin, ter-
minating at subdistal excavation. Other
synapomorphies that are homoplasous in
POORE: FAMILIES OF ISOPODA VALVIFERA 223
other arcturids are pereiopods 2–4 with weak
filter setation and a short dactylus and seti-
form unguis.
Wägele (1989) erected the subfamily Holi-
doteinae to include Holidotea and Aus-
troarcturus. Three synapomorphies define the
subfamily in his cladogram: head and
pereionites 1–4 shortened, pereion flattened
and eyes dorsal; head with a keel; and uropo-
dal rami short and with a stout seta. Only the
last of these character states is true for the
three genera united by the new cladistic
analysis that includes Neoarcturus. Full fam-
ily rank is warranted. A revision of the fam-
ily and resolution of complex nomenclatural
issues resulting from use of the nomen nudum
Microarcturus (Poore, 1991b) is in prepara-
tion for the Annals of the South African Mu-
seum.
Species of Neoarcturus have a form simi-
lar to antarcturids, but the other two genera
are quite flattened and limpet-like. Neoarc-
turus is a shelf and slope genus while the oth-
ers are only from more shelf depths. The fam-
ily is confined to southern Africa.
Antarcturidae, new family
Arcturidae auctorum (part).
Arcturinae.—Wägele, 1989: 138.—Wägele, 1991: 88
(part).
Type Genus.—Antarcturus zur Strassen, 1902.
Diagnosis.—Body flexed between pereionites
4 and 5. Head and pereionite 1 fused. Pereion-
ite 4 of similar length to pereionite 3. All
pleonites fused into pleotelson. Body strongly
spinose, with at least dorsal and dorsolateral
pairs of spines, often dominated by pair near
end of pleotelson; pleotelson without dorso-
lateral ridges ending in mediodorsal posterior
spine. Dorsal coxal plates 2–7 obsolete, bases
of pereiopods exposed. Mouthparts and
pereiopod 1 visible in lateral view. Eyes well
developed, or reduced or lost.
Antenna 2 flagellum multiarticulate, or of
2 or 3 articles plus distal claw. Pereiopod 1
a gnathopod, pereiopods 2–4 elongated, dif-
ferentiated from ambulatory pereiopods 5–7.
Pereiopod 1 dactylus evenly curved along an-
terior margin, evenly tapering. Pereiopods
2–4 with paired long setae along posterior
margins evenly and well developed; with
prominent dactylus, unguis short; pereiopod
4 similar to pereiopod 3. Pereiopods of males
without dense fur of fine setae. Uropodal ex-
opod (smaller ramus) tapering (with termi-
nal setae only), more than half as long as en-
dopod (when present).
Oostegites 1–4 functional, 5 absent; ooste-
gites 1–4 supported by coxal lobes. Penes
fused as a single penial plate; penial plate api-
cally simple or barely slit. Pleopod 1 pedun-
cle more elongate than on other pleopods;
with marginal setae on rami longer than or
equal to length of rami. Pleopod 1 exopod of
male thickened and with groove on posterior
face, with few simple setae along straight lat-
eral margin; with groove on posterior face of
exopod ending distolaterally or laterally on
simple margin. Pleopod 2 of male with ap-
pendix masculina about as long as endopod,
basally less than half width of endopod.
Included Genera (with numbers of described
species).—Abyssarcturus Kussakin and
Vasina, 1995 (1); Acantharcturus Schultz,
1981 (1); Antarcturus zur Strassen, 1902 (26);
Caecarcturus Schultz, 1981 (1); Chaetarc-
turus Brandt, 1990 (20); Cylindrarcturus
Schultz, 1981 (2); Fissarcturus Brandt, 1990
(9); Globarcturus Kussakin and Vasina, 1994
(1); Litarcturus Brandt, 1990 (7); Mixarcturus
Brandt, 1990 (3); Oxyarcturus Brandt, 1990
(3); Pleuroprion zur Strassen, 1903 (11);
Spinarcturus Kensley, 1978b (1); Thermoarc-
turus Paul and Menzies, 1971 (1); Tuberarc-
turus Brandt, 1990 (3) (90 species in all).
Remarks.—The new family is erected to dif-
ferentiate a large group of genera tradition-
ally placed in the Arcturidae. Nordenstam
(1933) diagnosed what he called the “Antarc-
turus group” to include what I am calling
Antarcturidae, but he included Dolichiscus
(now an austrarcturellid) and his nomen
nudum Microarcturus (most species now holi-
doteids). His diagnostic characters are com-
plete fusion of the head and pereionite 1,
complete fusion of pleonites, lateral margins
of the head and pereionite 1 not expanded
downwards, pereiopod 1 subchelate, and the
exopod of the male pleopod 1 with a diago-
nal groove.
Antarcturid genera vary considerably in
form. All have cylindrical, slightly geniculate
bodies. None is as strongly bent as austrarc-
turellids. The body is typically spinose or tu-
berculose, and sculpture has been used to dis-
tinguish genera (Brandt, 1990). While sculp-
ture is diverse, it does provide the only
224 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 21, NO. 1, 2001
probable synapomorphy of the family. Most
species are spinose, with the spines in longi-
tudinal rows on most body segments. The pair
of stronger spines near or at the apex of the
pleotelson is characteristic, and a homologue
is not seen in any other family.
Wägele (1989: Fig. 68) analysed the for-
mer Arcturidae (as a subfamily) but discov-
ered few hierarchical groups of genera. He
did not use the form of pereiopod 1 and male
pleopod 1 as characters and so discovered no
grouping equivalent to Antarcturidae.
Most of the species previously treated as
arcturids from Antarctica, where they are di-
verse and abundant (Brandt, 1990; Wägele,
1991), are, in my view, members of Antarc-
turidae. The family is most diverse in the
Southern Ocean and is the dominant val-
viferan group in the deep sea of both hemi-
spheres.
Austrarcturellidae Poore and
Bardsley, 1992
Austrarcturellidae Poore and Bardsley, 1992: 845.
Diagnosis.—Body flexed between pereionites
4 and 5. Head and pereionite 1 fused. Pereion-
ite 4 of similar length to pereionite 3. All
pleonites fused into pleotelson, or pleonite 1
articulating with fused pleotelson (most
species of Dolichiscus). Body variously tu-
berculate or spinose but never with posterior
dorsolateral pair of strong spines on pleotel-
son; pleotelson with dorsolateral ridges usu-
ally ending in mediodorsal posterior spine.
Dorsal coxal plates 2–7 obsolete, bases of
pereiopods exposed. Mouthparts and pereio-
pod 1 visible in lateral view. Eyes well de-
veloped, or reduced or lost.
Antenna 2 flagellum of 2 or 3 articles plus
distal claw. Pereiopod 1 a gnathopod,
pereiopods 2–4 elongated, differentiated from
ambulatory pereiopods 5–7. Pereiopod 1
dactylus usually with anterior lobe on ante-
rior margin, constricted and tapering distally.
Pereiopods 2–4 with paired long setae along
posterior margins evenly and well developed;
with minute dactylus, unguis setiform; pereio-
pod 4 shorter and less setose than pereiopods
2 and 3. Pereiopods of males without dense
fur of fine setae. Uropodal exopod (smaller ra-
mus) tapering (with terminal setae only), more
than half as long as endopod (when present).
Oostegites 1–4 functional, 5 vestigial
lobes, or 1–4 functional, 5 absent; oostegites
1–4 supported by coxal lobes. Penes fused
as a single penial plate; penial plate apically
simple or barely slit. Pleopod 1 peduncle
more elongate than on other pleopods; with
marginal setae on rami longer than or equal
to length of rami. Pleopod 1 exopod of male
thickened and with groove on posterior face,
with few simple setae along straight lateral
margin; with groove on posterior face of ex-
opod ending distolaterally or laterally on
simple margin (Dolichiscus), or ending on
basally derived branch of exopod. Pleopod 2
of male with appendix masculina twice length
of endopod, basally less than half width of
endopod.
Included Genera (with numbers of described
species).—Austrarcturella Poore and Bards-
ley, 1992 (14); Abyssarcturella Poore and
Bardsley, 1992 (2); Dolichiscus Richardson,
1913 (23); Pseudarcturella Tattersall, 1921
(2); Scyllarcturella Poore and Bardsley, 1992
(1) (42 species in all).
Remarks.—The original definition of the Aus-
trarcturellidae included four genera. It is here
expanded to include Dolichiscus.
The family, as originally defined, was
strongly united on the “boat-shaped” pleotel-
son with middorsal posterior spine, vestigial
dactyli with setiform unguis on pereiopods
2–4, smaller pereiopod 4, lateral lobe on the
male pleopod 1 exopod, and presence of re-
duced oostegites 5. Dolichiscus shares a sim-
ilar pleotelson and pereiopod 1 dactylus but
does not possess the lateral lobe of the male
pleopod 1 nor oostegites 5. All genera pos-
sess an elongate pleonite 1, weakly articulat-
ing with the pleotelson in most species of
Dolichiscus, and more elongate pereiopods
5–7 than is typical in antarcturids. Wägele
(1989: Fig. 68) recognised the similarity of
the pereiopod 1 and pleotelson of Pseudarc-
turella and Dolichiscus. Christoph Held (Ruhr
Universitat, Bochum) has found molecular
evidence from a 500 basepair fragment of the
mitochondrial large subunit ribosomal gene
(16S rDNA) that supports the distinction of
Dolichiscus from Antarcturus and similar
antarcturid genera (personal communication).
He was not able to compare it with other aus-
trarcturellids.
The four original members of the Austrarc-
turellidae comprise a well-defined clade of
species on the Australian shelf and slope and
POORE: FAMILIES OF ISOPODA VALVIFERA 225
nearby Tasman Sea. Dolichiscus is more
widespread, most species being in the deep
Southern Ocean but others in deep environ-
ments just north of the equator.
Xenarcturidae Sheppard, 1957
Xenarcturidae Sheppard, 1957: 182–184.
Xenarcturinae.—Wägele, 1989: 138 (part).
Diagnosis.—Body strongly vaulted. Head and
pereionite 1 fused. Pereionite 4 of similar
length to pereionite 3. All pleonites fused into
pleotelson. Body setose, not tuberculate; pleo-
telson without dorsolateral ridges ending in
mediodorsal posterior spine. Dorsal coxal
plates 2–7 more or less ventrally expanded
over bases of pereiopods. Mouthparts and
pereiopod 1 visible in lateral view. Eyes well
developed.
Antenna 2 flagellum of 2 or 3 articles plus
distal claw. Pereiopod 1 a gnathopod,
pereiopods 2 and 3 elongated, differentiated
from ambulatory pereiopods 4–7. Pereiopod
1 dactylus evenly curved along anterior mar-
gin, evenly tapering. Pereiopods 2 and 3 with
scattered long setae along posterior margins;
with prominent dactylus, unguis short;
pereiopod 4 different from pereiopod 3, sim-
ilar to pereiopod 5. Pereiopods of males with-
out dense fur of fine setae. Uropodal exopod
(smaller ramus) tapering (with terminal se-
tae only), more than half as long as endopod.
Oostegites 1–4 functional, 5 absent; ooste-
gites 1–4 not supported by coxal lobes. Penes
fused as a single penial plate; penial plate api-
cally simple or barely slit. Pleopod 1 pedun-
cle more elongate than on other pleopods;
with marginal setae on rami longer than or
equal to length of rami. Pleopod 1 exopod of
male thickened and with groove on posterior
face, with few simple setae along straight lat-
eral margin; with groove on posterior face of
exopod ending on tapering distolateral api-
cal extension. Pleopod 2 of male with ap-
pendix masculina about as long as endopod,
basally less than half width of endopod.
Included Genus (with number of described
species).—Xenarcturus Sheppard, 1957 (1).
Remarks.—This monotypic family is recog-
nised by the flat habitus and by pereiopod 4
being ambulatory rather than setose like
pereiopods 3 and 4 (Park, 1995). In this the
pereiopod symmetry differs from that in all
other valviferans. Wägele (1989) treated the
family as a subfamily of Arcturidae s. l.
Arcturididae, new family
Pseudidotheidae.—Hale, 1946: 168 (part).
Pseudidotheinae.—Wägele, 1989: 137.—Wägele, 1991:
80 (part).
Type Genus.—Arcturides Studer, 1882.
Diagnosis.—Body straight, more or less
cylindrical. Head and pereionite 1 fused.
Pereionite 4 of similar length to pereionite
3. All pleonites fused into pleotelson. Body
variously tuberculate or spinose but never
with posterior dorsolateral pair of strong
spines on pleotelson; pleotelson without dor-
solateral ridges ending in mediodorsal pos-
terior spine. Dorsal coxal plates 2–7 obsolete,
bases of pereiopods exposed. Mouthparts and
pereiopod 1 visible in lateral view. Eyes well
developed.
Antenna 2 flagellum of 2 or 3 articles plus
distal claw. Pereiopod 1 a gnathopod, pereio-
pods 2–4 scarcely differentiated from ambu-
latory pereiopods 5–7. Pereiopod 1 dactylus
evenly curved along anterior margin, evenly
tapering. Pereiopods 2–4 with irregular fine
setae and marginal robust setae; with promi-
nent dactylus, unguis short; pereiopod 4 sim-
ilar to pereiopod 3. Pereiopods of males with-
out dense fur of fine setae. Uropodal exopod
(smaller ramus) tapering (with terminal se-
tae only), more than half as long as endopod.
Oostegites 1–4 functional, 5 absent; ooste-
gites 1–4 supported by coxal lobes. Penes
fused as a single penial plate; penial plate api-
cally simple or barely slit. Pleopod 1 pedun-
cle more elongate than on other pleopods;
with marginal setae on rami longer than or
equal to length of rami. Pleopod 1 exopod of
male thickened and with groove on posterior
face, with few simple setae along straight lat-
eral margin; with groove on posterior face of
exopod ending on tapering distolateral api-
cal extension. Pleopod 2 of male with ap-
pendix masculina about as long as endopod,
basally less than half width of endopod.
Included Genus (with number of described
species).—Arcturides Studer, 1882 (2).
Remarks.—The cylindrical body with essen-
tially similar ambulatory pereiopods charac-
terises the family which otherwise has antarc-
turid-type male pleopods (Hale, 1946). This
226 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 21, NO. 1, 2001
combination of characters suggests that the
ancestral arcturoid was a straight isopod and
that an erect body with filtering setae on an-
terior pereiopods probably arose more than
once. Only two species of Arcturides are
known, both from hydroids near subantarc-
tic islands of the Southern Indian Ocean.
Pseudidotheidae Ohlin, 1901
Pseudidotheidae Ohlin, 1901: 274–276.
Pseudidotheinae.—Wägele, 1989: 137.—Wägele, 1991:
80 (part).
Diagnosis.—Body strongly vaulted. Head and
pereionite 1 fused. Pereionite 4 of similar
length to pereionite 3. All pleonites fused into
pleotelson. Body variously tuberculate or
spinose but never with posterior dorsolateral
pair of strong spines on pleotelson; pleotel-
son without dorsolateral ridges ending in
mediodorsal posterior spine. Dorsal coxal
plates 2–7 obsolete, bases of pereiopods ex-
posed. Mouthparts and pereiopod 1 visible
in lateral view. Eyes well developed.
Antenna 2 flagellum of 2 or 3 articles plus
distal claw. Pereiopod 1 a gnathopod, pereio-
pods 2 and 3 differentiated from ambulatory
pereiopods 4–7. Pereiopod 1 dactylus evenly
curved along anterior margin, evenly taper-
ing. Pereiopods 2–4 raptorial, articles broad
and with posterior robust setae; with promi-
nent dactylus, unguis short; pereiopod 4 sim-
ilar to pereiopod 3. Pereiopods of males with-
out dense fur of fine setae. Uropodal exopod
(smaller ramus) tapering (with terminal se-
tae only), more than half as long as endopod.
Oostegites 1–4 functional, 5 absent; ooste-
gites 1–4 not supported by coxal lobes. Penes
fused as a single penial plate; penial plate api-
cally simple or barely slit. Pleopod 1 pedun-
cle more elongate than on other pleopods;
with marginal setae on rami longer than or
equal to length of rami. Pleopod 1 exopod of
male thickened and with groove on posterior
face, with few simple setae along straight lat-
eral margin; with groove on posterior face of
exopod ending on tapering distolateral apical
extension. Pleopod 2 of male with appendix
masculina about as long as endopod, basally
less than half width of endopod.
Included Genus (with number of described
species).—Pseudidothea Ohlin, 1901 (3).
Remarks.—The pereiopods are the major fea-
tures separating this family from Antarcturi-
dae. In the new phylogenetic analysis, the
raptorial pereiopods are a unique apomorphy
for the family and genus. Wägele (1989)
treated the family as a subfamily of Arcturi-
dae, sensu lato, and included Arcturides in
it. The only synapomorphy defining the sub-
family in his cladogram is fusion of pleonites,
a character state of most arcturoids.
The three described species of Pseudi-
dothea are from subantarctic islands and New
Zealand. An undescribed species is common
in southern Australia.
Rectarcturidae, new family
Type Genus.—Rectarcturus Schultz, 1981.
Diagnosis.—Body strongly vaulted. Head and
pereionite 1 fused. Pereionite 4 of similar
length to pereionite 3. All pleonites fused into
pleotelson. Body variously tuberculate or
spinose but never with posterior dorsolateral
pair of strong spines on pleotelson; pleotel-
son without dorsolateral ridges ending in
mediodorsal posterior spine. Dorsal coxal
plates 2–7 obsolete, bases of pereiopods ex-
posed. Mouthparts and pereiopod 1 visible
in lateral view. Eyes well developed.
Antenna 2 flagellum of 2 or 3 articles plus
distal claw. Pereiopod 1 a gnathopod,
pereiopods 2–4 elongated, differentiated from
ambulatory pereiopods 5–7. Pereiopod 1
dactylus evenly curved along anterior margin,
evenly tapering. Pereiopods 2–4 with paired
long setae along posterior margins evenly and
well developed; with short dactylus, unguis
longer and setiform; pereiopod 4 similar to
pereiopod 3. Pereiopods of males without
dense fur of fine setae. Uropodal exopod
(smaller ramus) tapering (with terminal se-
tae only), more than half as long as endopod.
Oostegites 1–4 functional, 5 absent; ooste-
gites 1–4 not supported by coxal lobes.
Penes fused as a single penial plate; penial
plate apically simple or barely slit. Pleopod
1 peduncle more elongate than on other
pleopods; with marginal setae on rami longer
than or equal to length of rami. Pleopod 1 ex-
opod of male thickened and with groove on
posterior face, with few simple setae along
straight lateral margin; with groove on pos-
terior face of exopod ending distolaterally or
laterally on simple margin. Pleopod 2 of male
with appendix masculina about as long as en-
dopod, basally less than half width of endo-
pod.
POORE: FAMILIES OF ISOPODA VALVIFERA 227
Included Genus (with number of described
species).—Rectarcturus Schultz, 1981 (4).
Remarks.—The genus Rectarcturus is enig-
matic, combining features of the Antarcturi-
dae and Holidoteidae. Like both of these,
pereiopods 2–4 bear filtering setae, and the
male pleopod 1 is of the thickened, grooved
type. The body is straight like Holidoteidae,
but the uropodal rami are not of the peculiar
holidoteid form. The straight body and ab-
sence of paired pleotelsonic spines distinguish
it from most antarcturids. The cladistic analy-
sis cannot align the genus with either group,
nor with the other minor families, so a sepa-
rate family is justified. It is unclear whether
the combined presence of filtering setae with
a straight body shown in Rectarcturus is an-
cestral to the flexed situation seen in antarc-
turids and austrarcturellids or vice versa. It
is possible that the long setae on pereiopods
2–4 arose first for benthic scraping rather than
filter feeding from the plankton. As well as
the four described species from the far south-
western Atlantic (Park and Wägele, 1995) are
six undescribed species from Australian and
nearby shelf and deep habitats.
ACKNOWLEDGEMENTS
This paper results from discussions over many years
with my collaborators, Helen Lew Ton and Tania Bards-
ley, whom I thank for their considerable contribution. The
paper benefited from discussion with Angelika Brandt. The
work was supported by grants from the Australian Bio-
logical Resources Study. I thank curators of numerous mu-
seums who lent material. This paper is offered to Journal
of Crustacean Biology as a tribute to the substantial con-
tribution of Arthur Humes, its editor from 1981 to 1999.
LITERATURE CITED
Adams, A. 1852. Zoology. Pp. 201–216 in P. C. Suther-
land, ed. Journal of a voyage in Baffin’s Bay and Bar-
row Straits, in the years 1850–1851 performed by H.M.
ships “Lady Franklin” and “Sophia”, under the com-
mand of Mr. William Penny, in search of the missing
crews of H.M. ships “Erebus” and “Terror”: with . . .
observations on the natural history and physical fea-
tures of the countries and frozen seas visited. Vol. 2.
Longman Group Ltd, London.
Barnard, K. H. 1914a. Contributions to the crustacean
fauna of South Africa. 1. Additions to the marine
Isopoda.—Annals of the South African Museum 10:
197–230.
———. 1914b. Contributions to the crustacean fauna of
South Africa. 3. Additions to the marine Isopoda, with
notes on some previously incompletely known
species.—Annals of the South African Museum 10:
325a–358a, 359–442.
———. 1920. Contributions to the crustacean fauna of
South Africa. No. 6. Further additions to the list of
marine Isopoda.—Annals of the South African Museum
17: 319–438.
Bate, C. S. 1863. On some new Australian species of
Crustacea.—Proceedings of the Zoological Society of
London 1863: 498–505.
———, and J. O. Westwood. 1868. A history of the
British sessile-eyed Crustacea. Vol. 2. edition. John Van
Voorst, London. 536 pp.
Benedict, J. E. 1901. [Erichsonella Benedict, new name.]
P. 542 in Richardson, 1901, cited below.
Brandt, A. 1990. Antarctic valviferans (Crustacea,
Isopoda, Valvifera) new genera, new species and re-
descriptions. E. J. Brill, Leiden. 176 pp.
Brusca, R. C. 1984. Phylogeny, evolution and biogeog-
raphy of the marine isopod subfamily Idoteinae (Crus-
tacea: Isopoda: Idoteidae).—Transactions of the San
Diego Society of Natural History 20: 99–134.
———, and B. R. Wallerstein. 1979. The marine isopod
crustaceans of the Gulf of California II. Idoteidae: new
genus and species, range extensions, and comments on
evolution and taxonomy within the family.—Proceed-
ings of the Biological Society of Washington 92:
253–271.
———, and G. D. F. Wilson. 1991. Aphylogenetic analy-
sis of the Isopoda with some classificatory recommen-
dations.—Memoirs of the Queensland Museum 31:
143–204.
Collinge, W. E. 1917a. On the oral appendages of cer-
tain species of marine Isopoda.—Zoological Journal of
the Linnean Society 34: 65–92.
———. 1917b. Arevision of the British Idoteidae, a fam-
ily of marine Isopoda.—Transactions of the Royal So-
ciety of Edinburgh 51: 721–760.
Cordiner, C. 1793. Remarkable ruins, and romantic
prospects, of North Britain. With ancient monuments,
and singular subjects of natural history. Peter Mazell,
London. 96 pp., plates with letterpress.
Daguerre de Hureaux, N., and B. Elkaïm. 1972. Contri-
bution à l’étude des isopodes marins du Maroc:
Parachiridotea n. genre panousei nelle espèce (Val-
vifère, Idoteidae, Mesidoteinae).—Bulletin de la So-
ciété des Sciences Naturelles et Physiques du Maroc
52: 147–149.
Dallwitz, M. J., T. A. Paine, and E. J. Zurcher. 1997.
User’s guide to the DELTA system. A general system
for processing taxonomic descriptions. CSIRO Divi-
sion of Entomology, Canberra. 160 pp.
Dana, J. D. 1849. Conspectus crustaceorum quae in or-
bis terrarum circumnavigatione, Carolo Wilkes e classe
Reipublicae, Foederate Duce, lexit et descripsit (con-
tinued.).—American Journal of Sciences and Arts 8:
424–428.
———. 1853. Crustacea. Part II.—United States Ex-
ploring Expedition during the years 1838, 1839, 1840,
1841, 1842 under the command of Charles Wilkes,
U.S.N. 13: 691–1618, with a folio atlas of 96 plates.
Eights, J. 1852. Of a new animal belonging to the Crus-
tacea, discovered in the Antarctic seas, by the author.—
Transactions of the Albany Institute 2: 331–334.
Fabricius, J. C. 1798. Supplementum Entomologiae Sys-
tematicae. Proft and Storch, Hafniae. 572 pp.
Guérin-Méneville, F. E. 1843. Crustacés. P. 48, 35 pls.
in G. Cuvier, ed. Iconographie du Règne animal de G.
Cuvier, ou représentation d’après nature de l’une des
espèces les plus remarquables et souvent non encore
figurées de chaque genre d’animaux. Vol. 3. Baillière,
Paris.
228 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 21, NO. 1, 2001
Hale, H. M. 1924. Notes on Australian Crustacea. No.
3.—Transactions of the Royal Society of South Aus-
tralia 48: 209–225.
———. 1929. Crustacea from Princess Charlotte Bay,
North Queensland. The Isopoda and Stomatopoda.—
Transactions of the Royal Society of South Australia
53: 33–36.
———. 1946. Isopoda–Valvifera.—B.A.N.Z. Antarctic
Research Expedition, 1929–1931. Reports-Series B
(Zoology and Botany) 5: 161–212.
Harger, O. 1878. Descriptions of new genera and species
of Isopoda, from New England and adjacent regions.—
American Journal of Sciences and Arts 15: 373–379.
Holthuis, L. B. 1964. Saduriella a new genus of Isopoda
Valvifera from northwestern Spain.—Zoologische
Mededelingen, Leiden 40: 29–35.
Hurley, D. E. 1961. A checklist and key to the Crustacea
Isopoda of New Zealand and Subantarctic Islands.—
Transactions of the Royal Society of New Zealand (Zo-
ology) 1: 259–292.
Jones, M. B., and G. D. Fenwick. 1978. Maoridotea nay-
lori, a new genus and species of isopod (Valvifera,
Idoteidae, Chaetilinae) from the Kaikoura Peninsula,
New Zealand.—Journal of Natural History 12:
617–625.
Kensley, B. 1975. Marine Isopoda from the continental
shelf of South Africa.—Annals of the South African
Museum 67: 35–89.
———. 1977. New records of marine Crustacea Isopoda
from South Africa.—Annals of the South African Mu-
seum 72: 239–265.
———. 1978a. Guide to the marine isopods of southern
Africa. Trustees of the South African Museum, Cape
Town. 173 pp.
———. 1978b. The South African Museum’s Meiring
Naude cruises. Part 7. Marine Isopoda.—Annals of the
South African Museum 74: 125–157.
———. 1984. The South African Museum’s Meiring
Naude Cruises. Part 15. Marine Isopoda of the 1977,
1978, 1979 cruises.—Annals of the South African Mu-
seum 93: 213–301.
———, and H. W. Kaufman. 1978. Cleantioides, a new
idoteid isopod genus from Baja California and
Panama.—Proceedings of the Biological Society of
Washington 91: 658–665.
———, and M. Schotte. 1989. Guide to the marine iso-
pod crustaceans of the Caribbean. Smithsonian Insti-
tution Press, Washington, D.C., and London. 308 pp.
Koehler, R. 1911. Arcturidés nouveaux provenant des
campagnes de la “Princesse-Alice” ou appartenant au
Musée Océanographique de Monaco.—Bulletin de l’In-
stitut Océanographique de Monaco 214: 1–65.
Kussakin, O. G. 1972. Isopoda from the coastal zone of
the Kurile Islands. III. Three new arcturids from the
Middle Kuriles with taxonomic remarks on the family
Arcturidae.—Crustaceana Supplement 3: 178–189.
———. 1982. Marine and brackish-water Crustacea
(Isopoda) of cold and temperate waters of the North-
ern Hemisphere. Suborders Anthuridea, Microcere-
beridea, Valvifera, Tyloidea.—Opredeliteli po Faune
SSR, Akademiya Nauk, SSSR 131: 1–461. [In Russ-
ian.]
———, and G. S. Vasina. 1994. Description of Glo-
barcturus angelikae gen. et sp. n., the first Antarctic
hadal arcturid from the South Sandwich Trench (Crus-
tacea, Isopoda: Arcturidae).—Zoosystematica Rossica
2: 241–245.
———, and ———. 1995. Antarctic hadal arcturids, with
descriptions of a new genus and five new species
(Isopoda: Valvifera: Arcturidae).—Zoosystematica
Rossica 3: 207–228.
Latreille, P. A. 1829. Les Crustacés, les Arachnides et
les Insectes, distribués en familles naturelles. Pp.
i–xxvii, 1–584 in G. Cuvier, ed. Le Règne Animal dis-
tribué d’après son organisation, pour servir de base à
l’histoire naturelle des animaux et d’introduction à
l’anatomie comparée. Vol. 4. Déterville, Paris.
Menzies, R. J., and T. E. Bowman. 1956. Emended de-
scription and assignment to the new genus Ronalea of
the idotheid isopod Erichsonella pseudoculata
Boone.—Proceedings of the United States National
Museum 106: 339–343.
———, and W. L. Kruczynski. 1983. Isopod Crustacea
(exclusive of Epicaridea).—Memoirs of the Hourglass
Cruises 6: 1–126.
Moreira, P. S. 1974. Moplisa, a new genus of idoteid iso-
pod from southern South America.—Crustaceana 26:
149–154.
Müller, H. G. 1993. Arcturidae (Isopoda) from the Santa
Marta area, northern Columbia, with a review of the
shallow-water species from the Caribbean Sea and Gulf
of Mexico.—Mitteilungen aus dem Zoologischen Mu-
seum in Berlin 69: 317–337.
Nicholls, G. E. 1937. On the freshwater Idoteidae of New
Zealand (Crustacea, Isopoda).—Annals and Magazine
of Natural History (10)19: 113–136.
Nierstrasz, H. F. 1941. Die Isopoden der Siboga-Expedi-
tion. IV. Isopoda Genuina. III. Gnathiidea, Anthuridea,
Valvifera, Asellota, Phreatocoidea.—Siboga Expéditie
19: 235–308.
Nordenstam, A. 1933. Marine Isopoda of the families
Serolidae, Idotheidae, Pseudidotheidae, Arcturidae,
Parasellidae and Stenetriidae mainly from the South At-
lantic.—Further Zoological Results of the Swedish
Antarctic Expedition, 1901–1903 3: 1–284, 2 pls., er-
rata.
Ohlin, A. 1901. Isopoda from Tierra del Fuego and Pata-
gonia.—Wissenschaftliche Ergebnisse der Schwedis-
chen Expedition nach den Magellansländern
1895–1897 2: 261–306.
Park, J.-Y. 1995. Xenarcturus spinulosus Sheppard, 1957
(Crustacea, Isopoda, Valvifera): redescription of a spec-
imen from the Strait of Magellan.—Bulletin Zoölogisch
Museum, Universiteit van Amsterdam 14: 145–152.
———, and J. W. Wägele. 1995. On a small collection
of Valvifera (Crustacea Isopoda) from the Magellan
Strait, with a description of Platidotea magellanica n.
gen. n. sp.—Bulletin Zoölogisch Museum, Universiteit
van Amsterdam 14: 57–99.
Paul, A. Z., and R. J. Menzies. 1971. Sub-tidal isopods
of the Fosa de Cariaco, Venezuela, with descriptions of
two new genera and twelve new species.—Boletín del
Instituto Oceanografico, Universidad de Oriente 10:
29–48.
Poisson, R., and A. Maury. 1931. Arcturinella banyulen-
sis nov. gen., nov. sp., Crustacé Isopode nouveau (tribu
des Valvifera, famille des Arcturidae), capturé à
Banyuls (Pyr. Orientales).—Bulletin de l’Institut
Océanographique de Monaco 573: 1–14.
Poore, G. C. B. 1978. Austrochaetilia capeli, a new genus
and species of chaetiline idoteid (Isopoda) from Port
Phillip Bay, Australia.—Crustaceana 33: 113–118.
———. 1984. Clarification of the monotypic genera
Chiriscus and Symmius (Crustacea: Isopoda: Idotei-
POORE: FAMILIES OF ISOPODA VALVIFERA 229
dae).—Proceedings of the Biological Society of Wash-
ington 97: 71–77.
———. 1985. Australian chaetiliids (Crustacea: Isopoda:
Valvifera): a new genus, new species and remarks on
the family.—Memoirs of the Museum of Victoria 46:
153–172.
———. 1991a. Crustacea Isopoda: Deep-sea Chaetili-
idae (Valvifera) from New Caledonia and the Philip-
pines.—Mémoires du Muséum National d’Histoire
Naturelle, Paris (Zoologie) 152: 139–153.
———. 1991b. Neoarcturus Barnard, 1914: Diagnoses
of the genus and its type species and substitution for
the nomen nudum MicroarcturusNordenstam, 1933
(Isopoda, Arcturidae).—Annals of the South African
Museum 101: 1–8.
———. 1998. Deep-water Arcturidae (Crustacea,
Isopoda, Valvifera) from French collections in the
south-western Pacific Ocean.—Zoosystema 20:
379–399.
———, and T. M. Bardsley. 1992. Austrarcturellidae
(Crustacea: Isopoda: Valvifera), a new family from
Australasia.—Invertebrate Taxonomy 6: 843–908.
———, and H. M. Lew Ton. 1990. The Holognathidae
(Crustacea: Isopoda: Valvifera) expanded and rede-
fined on the basis of body-plan.—Invertebrate Tax-
onomy 4: 55–80.
———, and ———. 1993. Idoteidae of Australia and
New Zealand (Crustacea: Isopoda: Valvifera).—In-
vertebrate Taxonomy 7: 197–278.
Racovitza, É.-G., and R. Sevastos. 1910. Proidotea
haugi, n. g. n. sp. isopode Oligocène de Roumanie et
les Mesidoteini nouvelle sous-famille des Idothei-
dae.—Archives de Zoologie Expérimentale et
Générale 6: 175–200, pl. 9.
Richardson, H. 1899. Key to the isopods of the Pacific
Coast of North America, with descriptions of twenty-
two new species.—Proceedings of the United States
National Museum 21: 815–869.
———. 1901. Key to the isopods of the Atlantic coast
of North America with descriptions of new and little
known species.—Proceedings of the United States Na-
tional Museum 23: 493–579.
———. 1904. Contributions to the natural history of the
Isopoda. I. Isopoda collected in Japan in 1900 by the
U.S. Fish Commission steamer “Albatross”, and in the
year 1881 by the U.S.S. “Palos”.—Proceedings of the
United States National Museum 27: 1–89.
———. 1905. A monograph on the isopods of North
America.—United States National Museum Bulletin
54: VII–LIII, 1–727.
———. 1912. Description of a new species of isopod
of the genus Cleantis from Japan.—Proceedings of the
United States National Museum 42: 27–29.
———. 1913. Crustacés isopodes.—Deuxième Expédi-
tion Antarctique Française (1908–10) 3: 1–25.
Samouelle, G. 1819. The entomologists’ useful com-
pendium; or an introduction to the knowledge of British
Insects, comprising the best means of obtaining and
preserving them, and a description of the apparatus
generally used; together with the genera of Linné, and
modern methods of arranging the Classes Crustacea,
Myriapoda, spiders, mites and insects, from their affini-
ties and structure, according to the views of Dr. Leach.
Also an explanation of the terms used in entomology;
a calendar of the times of appearance and usual situa-
tions of near 3,000 species of British Insects; with in-
structions for collecting and fitting up objects for the
microscope. Thomas Boys, London. 496 pp., 12 pls.
Sars, G. O. 1882. Oversigt af Norges Crustaceer med
forlöbige Bemaerkninger over de nye eller mindre bek-
jendte Arter.—Forhandlinger i Videnskaps-Selskapet in
Kristiania 1882: 1–124.
———. 1897. An account of the Crustacea of Norway
with short descriptions and figures of all the species.
Vol. 2. Isopoda. Parts 5, 6. Idotheidae, Arcturidae, Asel-
lidae, Ianiridae, Munnidae. Pp. 81–116, pls. 33–48.
Bergen Museum, Bergen. 270 pp.
Schultz, G. A. 1981. Arcturidae from the Antarctic and
Southern Seas (Isopoda, Valvifera) Part I. Pp. 63–94
in Biology of the Antarctic Seas 10. Antarctic Research
Series. Vol. 32. American Geophysical Union.
Sheppard, E. M. 1957. Isopod Crustacea Part II. The sub-
order Valvifera. Families: Idoteidae, Pseudidotheidae
and Xenarcturidae fam. n. With a supplement to iso-
pod Crustacea, Part 1. The family Serolidae.—Dis-
covery Reports 29: 141–197.
Stebbing, T. R. R. 1900. On Crustacea brought by Dr.
Willey from the South Seas. Pp. 609–690 in A. Wil-
ley, ed. Zoological Results based on material from New
Guinea, New Britain, Loyalty Islands and elsewhere
. . . 1895, 1896 and 1897. Vol. 5.
———. 1902. South African Crustacea. Part 2.—Marine
Investigations in South Africa. Department of Agri-
culture, Cape Town: 1–92.
———. 1905. Report on the Isopoda collected by Pro-
fessor Herdman at Ceylon, in 1902.—Report to the
Government of Ceylon on the Pearl Oyster Fisheries of
the Gulf of Manaar, Supplementary Report 4: 1–64.
zur Strassen, O. 1902. Über die Gattung Arcturus und
die Arcturiden der Deutschen Tiefsee-Expedition.—Zo-
ologischer Anzeiger 25: 682–689.
———. 1903. Zusatz su meinem Artikel über die Arc-
turiden.—Zoologischer Anzeiger 26: 31.
Studer, T. 1882. Über eine neue Art Arcturus und eine neue
Gattung der Idotheiden.—Sitzungsberichte der Gesell-
schaft Naturforschender Freunde zu Berlin 1882: 56–58.
Swofford, D. L. 1998. PAUP*. Phylogenetic analysis us-
ing parsimony (*and other methods). Version 4. Sinauer
Associates, Sunderland, Mass. 128 pp.
Tattersall, W. M. 1921. Crustacea. Part VI.—Tanaidacea
and Isopoda.—British Antarctic “Terra Nova” Expe-
dition, Natural History Reports, Zoology 3: 191–258.
Thomson, G. M. 1879. Description of a new species of
isopodous crustacean (Idotea).—Transactions of the
New Zealand Institute, Zoology 1878: 250, 251.
———. 1904. A new family of Crustacea Isopoda.—An-
nals and Magazine of Natural History (7)14: 66–69.
Wägele, J. W. 1987. The feeding mechanism of Antarc-
turus and a redescription of A. spinacoronatus Schultz,
1978 (Crustacea: Isopoda: Valvifera).—Philosophical
Transactions of the Royal Society of London B 316:
429–458.
———. 1989. Evolution und phylogenetisches System
der Isopoda. Stand der Forschung und neue Erkennt-
nisse.—Zoologica (Stuttgart) 140: 1–262.
———. 1991. Antarctic Isopoda Valvifera. Koeltz Sci-
entific Books, Königstein. 213 pp. [Theses Zoologi-
cae Volume 14, Synopses of the Antarctic Benthos Vol-
ume 2.]
RECEIVED: 18 October 1999.
ACCEPTED: 10 July 2000.
230 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 21, NO. 1, 2001
... I, Con una excavación en el tercio anterior (Arcturidae); J, Con un lóbulo distal (Holidoteidae). K, Con un apéndice largo y delgado, "appendix masculina accesorio" (Austrarcturellidae). Modificado de: A y B, Wägele (1989); C-G, I-K, Poore (2001); H, King (2003). Brusca (1984), en un trabajo pionero, realiza una revisión sobre la sistemática y la filogenia de los valvíferos, y reconoce seis familias: Holognathidae, Xenarcturidae, Arcturidae, Amesopodidae, Pseudidotheidae e Idoteidae, esta última con 5 subfamilias (Idoteinae, Chaetiliinae, Parachiridoteinae, Glyptonotinae y Mesidoteinae). ...
... En tal sentido, otras relaciones filogenéticas fueron propuestas por diversos autores (Poore, 1985;Wägele, 1989;Poore y Lew Ton, 1990, 1993Poore y Bardsley, 1992). A partir del trabajo cladístico de Poore (2001), quien realiza un análisis filogenético basado en más de 30 caracteres morfológicos, se establecen las relaciones filogenéticas que se mantienen al día de hoy (Fig. 6B). En este trabajo, se reconocen 11 familias, a saber: Chaetiliidae, Holognathidae, Idoteidae, Arcturidae, Antarcturidae, Rectarcturidae, Xenarcturidae, Pseudidotheidae, Arcturididae, Holidoteidae y Austrarcturellidae. ...
... En este trabajo, se reconocen 11 familias, a saber: Chaetiliidae, Holognathidae, Idoteidae, Arcturidae, Antarcturidae, Rectarcturidae, Xenarcturidae, Pseudidotheidae, Arcturididae, Holidoteidae y Austrarcturellidae. Poore (2001) plantea que las familias que presentan cuerpos deprimidos, hábitos herbívoros, machos con penes independientes o fusionados sólo en la base corresponden a los grupos más basales dentro del suborden (Chaetiliidae, Idoteidae y Holognathidae). Por otro lado, las familias con cuerpos cilíndricos y geniculados, hábitos filtradores, machos con penes fusionados y "appendix masculina accesorio" sobre el pleópodo I se ubican entre las más derivadas. ...
Thesis
Los isópodos valvíferos de la familia Idoteidae son muy comunes en la zona deintermareal y en aguas someras de plataforma. A pesar de ser organismos conspicuos, frecuentemente hallados en muestras del Atlántico Sudoccidental, el conocimiento taxonómico del grupo aún dista de ser completo. En tal sentido, los objetivos de esta tesis son: (1) describir en forma detallada una nueva especie del género Edotia hallada en aguas del Talud Continental; (2) reportar el hallazgo de otras dos especies inéditas de dicho género, encontradas en aguas someras de Argentina y Uruguay; (3) dar a conocer los nuevos registros de distribución de las especies de Idoteidae del Mar Argentino y áreas adyacentes; y (4) realizar una revisión exhaustiva de las especies de Idoteidae del área de estudio, y confeccionar una clave que permita la identificación de las mismas. Para tal fin, se estudiaron un total de 136 muestras recolectadas entre los años 2001 y 2016, provenientes de 8 localidades costeras y de 9 campañas oceanográficas a bordo del BO Puerto Deseado. Además, se revisó el material depositado en la Colección Científica del Laboratorio de Invertebrados II (FCEyN), la Colección de Invertebrados del Museo Argentino de Ciencias Naturales “Bernardino Rivadavia” (MACN) y la colección del Centro Nacional Patagónico (CENPAT); como así también el material proveniente de Uruguay y las islas Georgias del Sur, cedido por colegas. A partir del material estudiado se describió en forma detallada la especie Edotia abyssalis n. sp., recolectada en el cañón submarino Mar del Plata a 3.282 m de profundidad. Esta especie difiere de sus congéneres por presentar pedúnculos oculares largos, sin omatidias; y por la presencia de carenas transversales en los pereionitos 1–5. El hallazgo de esta nueva especie representa el registro de mayor profundidad para la familia. La especie Edotia transversa es citada por primera vez en el Mar Argentino, desde Puerto Madryn hasta Puerto Deseado; y se extendieron los registros de distribución de E. oculata, E. bilobata y E. pulchra. También se discute el estatus taxonómico de 7 especies de Edotia: E. triloba, E. montosa, E. acuta, E. transversa, E. magellanica, E. chilensis y E. dahli, y dos especies de Idotea: I. balthica e I. brevicauda, quedando en evidencia la necesidad de realizar estudios moleculares para precisar la identidad de las mismas. Por último, se confeccionaron claves de identificación para las especies de Idoteidae presentes en el Mar Argentino y áreas adyacentes con el objetivo de acercar el conocimiento existente de esta familia a biólogos marinos no familiarizados con esta fauna. I
... Much more dominant in the North Atlantic towards the Arctic is the valviferan family Arcturidae Dana, 1849. Arcturids are filter feeders (e.g., Wägele 1987;Poore 2001) yet remain poorly understood, including their role in the food web (Poore and Bruce 2012). ...
... During the expeditions from which we report here, the family was collected at several sites on the GIF Ridge (Fig. 2). The arcturids are passively filter-feeding, benthic isopods (Wägele 1987;Poore 2001) with a dorsally flexed body, enabling the filtering legs (pereopods) 2-4 to be held above the substrate for feeding while the posterior legs are used for clinging to the substrate (Poore 2001). Their region of occurrence is known to have very productive surface waters and high total organic carbon content in the sediments was observed, which may explain the high abundances also of other suspension feeding peracarids as found for amphipod crustaceans ). ...
... During the expeditions from which we report here, the family was collected at several sites on the GIF Ridge (Fig. 2). The arcturids are passively filter-feeding, benthic isopods (Wägele 1987;Poore 2001) with a dorsally flexed body, enabling the filtering legs (pereopods) 2-4 to be held above the substrate for feeding while the posterior legs are used for clinging to the substrate (Poore 2001). Their region of occurrence is known to have very productive surface waters and high total organic carbon content in the sediments was observed, which may explain the high abundances also of other suspension feeding peracarids as found for amphipod crustaceans ). ...
Article
Full-text available
Since the 1990s, the marine benthos of the Greenland–Iceland–Faeroe (GIF) Ridge has been sampled through the BIOICE (Benthic Invertebrates of Icelandic waters) and subsequent IceAGE (Icelandic Marine Animals: Genetics and Ecology) projects. Isopod crustaceans formed one of the prominent macrofaunal groups. Most isopod families occurred on both sides of the ridge, but showed side-specific abundance patterns reflecting known distribution from the literature. Our results from 35,536 isopod specimens from 55 epibenthic sled stations show a depth pattern at the family level indicating typical shallow water families like, for example, Paramunnidae or typical deep-water families like, for example, Haploniscidae and Ischnomesidae, while other families did not show a clear depth trend. We hypothesize that the ridge influences the distribution of the families through its effects on the hydrography and sediment characteristics. Total organic carbon (TOC) and mud content significantly explained isopod family distributions, possibly reflecting different habitat use and lifestyle (e.g., infaunal, epifaunal). Our analysis of a subset of 27 selected BIOICE and IceAGE stations and 100 isopod species (22,574 specimens), mostly covering the upper 1000 m depths between Iceland and Norway along the Iceland–Faeroe Ridge (IFR), resulted in four main species assemblages differing in species diversity. Whereas north of the IFR, we found 76 species; south of the IFR, we found 52 species; 40 species occurred both north and south of the IFR. Although the subset of selected stations is limited to a comparably small portion of the IceAGE sampling grid and to a comparably restricted depth range of the upper 1000 m, our result shows the slope area of Northeast Iceland and around the Faeroes and the Norwegian Channel with the highest number of species, especially stations in the thermocline between 400 and 800 m depth, where we observed the turnover from shallow to deep-water faunal elements.
... Additionally, species of polychaetes and peracarids were classified (based on Poore, 2001;Scipione, 2013;Faulwetter et al., 2014;Guerra-García et al., 2014;Jumars et al., 2015;Larsen et al., 2015) into five trophic guilds: filter feeders, detritivores, herbivores, predators and omnivores. The multivariate analyses were then repeated on the dataset of trophic guilds abundance, after fourth root transformation for polychaetes and square root transformation for peracarids. ...
Article
In coastal marine ecosystems coralline algae often create biogenic reefs. These calcareous algal reefs affect their associated invertebrate communities via diurnal oscillations in photosynthesis, respiration and calcification processes. Little is known about how these biogenic reefs function and how they will be affected by climate change. We investigated the winter response of a Mediterranean intertidal biogenic reef, Ellisolandia elongate exposed in the laboratory to reduced pH conditions (i.e. ambient pH – 0.3, RCP 8.5) together with an extreme heatwave event (+1.4°C for 15 days). Response variables considered both the algal physiology (calcification and photosynthetic rates) and community structure of the associated invertebrates (at taxonomic and functional level). The combination of a reduced pH with a heatwave event caused Ellisolandia elongata to significantly increase photosynthetic activity. The high variability of calcification that occurred during simulated night time conditions, indicates that there is not a simple, linear relationship between these two and may indicate that it will resilient to future conditions of climate change. In contrast, the associated fauna were particularly negatively affected by the heatwave event, which impoverished the communities as opportunistic taxa became dominant. Local increases in oxygen and pH driven by the algae can buffer the microhabitat in the algal fronds, thus favouring the survival of small invertebrates.
... Macrochiridothea Ohlin, 1901, and its current synonym Chiriscus Richardson, 1911, genera of the isopod family Chaetiliidae Dana, 1849(Poore, 2001 are represented in South America by ten described species (Carvacho, 1997;Moreira, 1973). These species are distributed south of 23ºS on the Atlantic coast of southern Brazil, Uruguay and Argentina and the Pacific coast of Chile. ...
Article
A new species, Macrochiridothea estuariae, is described from the estuary of the Río de la Plata. It differs from other species of the genus in having weakly defined incisions on the side of the head. The genus Chiriscus Richardson, 1911, previously synonymised with Macrochiridothea Ohlin, 1901 is revived on the basis of a lobed article 4 on antenna 2 and a longer pereonite 7 to include the type species, Chiriscus australis Richardson, 1911, and C. giambiagiae (Torti & Bastida, 1972) transferred from Macrochiridothea. Nine other species of Macrochiridothea from southern South America and another from New Zealand are briefly diagnosed. A key is provided.
... We tested whether plant feeding is associated with higher species richness in the Crustacea by contrasting the number of species in the clades that include plant-feeding genera with the number of species in their sister clades. Clades were predominantly families or groups of families, given the taxonomic resolution of the most recently published phylogenies for higher-level taxa among the amphipods (63,64), isopods (65,66), and decapods (42,(67)(68)(69). The methods for determining which taxa to include in each sister contrast are detailed in the SI Text. ...
Article
Full-text available
Significance Understanding what morphological and behavioral traits promote the success of diverse groups of organisms is a major goal of evolutionary biology. The ability to consume novel food sources has been linked to the spectacular radiation of herbivorous insects that eat terrestrial plants on Earth. Among the crustaceans, the arthropod group that dominates aquatic environments, relatively few major taxa have overcome the challenges of consuming primary producers (plants and macroalgae). However, lineages that include plant material in their diets support more species than their most closely related lineages. The results of our analyses support the hypothesis that a shift in diet promotes speciation in this diverse and ecologically important animal group.
... According to Hessler and Wilson (1983) the presence or absence of eyes in a particular taxa can be used to interpret its activity migration to or from the deep sea. Among the suborder Valvifera, the dominant group in the deep sea is the family Antarcturidae (Poore, 2001), and it includes several blind species or species with rudimentary eyes (Birstein, 1963;Kussakin and Vasina, 1994, 1995, 1998. On the contrary, Idoteidae is a typical shallow water family; it includes 184 species and all of them present eyes, E. abyssalis n. sp. ...
Article
Edotia abyssalis n. sp. from the Mar del Plata submarine canyon, Southwest Atlantic Ocean is described. The finding of this new species represents the first record of the genus Edotia in the abyssal zone. E. abyssalis n. sp. can be distinguished from the remaining congeners by the presence of long and slender eyestalks without ommatidia. Additional records of distribution for E. oculata Ohlin, 1901, E. turberculata Guérin-Méneville, 1844, E. doellojuradoi Giambiagi, 1925, E. bilobata Nordenstam, 1933 and E. transversa Menzies, 1962 are presented. A key to the Edotia species from the Southern Hemisphere is given.
... In marine ecological Systems, resting stages constitute a "potential biodiversity" allowing a stmctural continuity in the life cycle against the functional discontinuity given by the disappearance of species from the water colurnn (BOERO et al. 1996). Resting stages may also represent an important food source for meiofaunal and macrobenthic taxa: keystone or diffuse predation on resting stages may act as a benthic key control on the pelagic system (ALBERTSSON & LEONARDSSON 2000, 2001. MARCUS & BOERO (1998) suggested that resting stages should be a fundamental biological link, via submarine canyons, in shelf-slope and shallow-deep sea coupling. ...
Article
Full-text available
In this first note, we present the taxonomic position and the differential diagnosis of the family Trichoniscidae. In our opinion from the common ancestor of Oniscidea two lineages evolved: a lineage evolved toward the complete disappearance of the genital apophyses leaving only two separated male genital openings (Infraorder Tylomorpha) while the other lineage evolved toward merging the two genital apophyses up to the fusion of the ejaculatory ducts and a single genital opening (Infraorder Ligiamorpha). Within Ligiamorpha, the family Trichoniscidae is included in Suprasection Orthogonopoda, Section Synocheta. We argue for the sister group relationship of Section Synocheta with Microcheta (Mesoniscidae) and not with Crinocheta, the most evolved group among the terrestrial Isopods.
Article
In the samples of the expedition SokhoBio (Sea of Okhotsk Biodiversity Studies) arcturoid isopods were present at eight sites in the Kuril Basin of the Sea of Okhotsk (1685-3366. m), the Bussol Strait (2327-2358. m), and the western abyssal slope of the Kuril-Kamchatka Trench (KKT) (3371-3377. m). They were represented by eight species of three genera and two families, Antarcturus, Chaetarcturus (Antarcturidae), and Neastacilla (Arcturidae). Six species turned out to be new to science. The composition of fauna and distribution of arcturoids in the Kuril Basin and the adjacent regions are discussed. A list of all arcturoid species known from the Sea of Okhotsk and the adjacent waters off the Pacific coast of the Kuril Islands and the Southeastern Kamchatka at depths > 500. m is provided. In the abyss of the Sea of Okhotsk two species (Chaetarcturus cf. beddardi (Gurjanova, 1935) and Neastacilla birsteini sp. nov.) were found. Neastacilla birsteini sp. nov., the dominant species in the abyss of the Kuril Basin, is described herewith. The new species differs from all other species of the genus by the 6-articled antennae I. N. birsteini sp. nov. most closely resembles N. anophthalma (Birstein, 1963) comb. nov. nov. Both species can be distinguished from all other species of the genus by the absence of eyes and a long article 5 of antenna I which is longer than articles 1-3 together. N. birsteini sp. nov. differs from N. anophthalma in the following characters: the pleon of the new species is 1.5 times longer than pereonite 4 and has an elongated distal part with a notch at the apex; the pereopod I carpus is 3.2 times as long as wide.
Article
Full-text available
We describe Koridotea hoonsooi, a new genus and new species of Idoteidae Samouelle, 1819 based on specimens collected using light traps in a sedimentary bottom of sand with seaweeds at 1–10 m depth from the southern coast of South Korea. The new genus is distinguished from other idoteid genera by the following combination of characters: pleonite 1 indicated by completely dorsal sutures, pleonites 2 and 3 with ventrolateral sutures only (pleotelsonic formula 1 + 2); maxillipedal palp articles 2 and 3 fused; coxae 2–7 without dorsal coxal plates; pereionite 7 without ventral W-shaped ridge; and pereiopods without spiniform setae on the palm of the propodus. We describe Synidotea wonkimi, a new species based on specimens collected using light traps in a sedimentary bottom of organic-rich mud with seaweeds at 3–7 m depth from the western coast of South Korea. This new species is distinguished from other congeneric species by the following combination of characters: dorsal surface of the body with minute tubercles; head with a single distinct median tubercle and frontal margin deeply concave; and apex of pleotelson with a rounded margin. We provide a key to the genera of Idoteidae and present the partial sequences of the mitochondrial cytochrome c oxidase subunit I (CO1) gene from the two new species. In addition, we discuss the heterogeneous genera of Idoteidae, which aims to eventually establish more precise diagnoses of the idoteid genera.
Article
The patterns of spatial distribution attained by the genera of Idoteinae are discussed in light of a cladistic analysis of the suborder Valvifera and the subfamily Idoteinae. A geographic cladogram of temperate Gondwanan shores is proposed. The subfamily Idoteinae appears to form 2 principal lines of descent, both arising in the Triassic or Jurassic. One of these lines remained closely tied to the Southern Hemisphere (primarily Old World) temperate marine shores from which the Idoteinae is derived. The other line invaded the Northern Hemisphere and various New World environments, and more recently (Cenozoic) underwent a radiation in the American tropics. The success of this latter lineage may be due to certain morphological and life history adaptations not found in New World species of the former line. The Valvifera probably originated in the temperate Southern Hemisphere, at least by Permean/Triassic times. Global distribution patterns of some genera can be ascribed most parsimoniously to vicariance processes, and in others to dispersal, ecological, phenomena, or a combination of processes.-from Author