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A New Spinicaudatan (Crustacea: Branchiopoda) from the Island of Olkhon (Lake Baikal, Russia) and the Zoogeography of East Asian Spinicaudata.

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Abstract

A spinicaudatan branchiopod crustacean, Baikalolkhonia tatianae gen. et sp. nov., is described from the Baikal region in Russia. The genus is assigned to the family Cyzicidae STEBBING, 1910, based on the absence of a frontal organ on the head, the absence of triangular epipodal laminae on the thoracopods, and the presence of a pair of large frontal spines on the telson. The main distinguishing characteristic is that the epipodal upper corners of many anterior thoracopods (including even the first pair) are transformed into "sausage-like organs." Since such epipodal processes have been until now unknown in the Cyzicidae, the diagnosis of the family is emended, and 2 newly defined subfamilies, Baikalolkhoniinae and Cyzicinae, are proposed. Up to the present, 11 species belonging to 7 genera in 4 families of Spinicaudata (Cyclestheriidae, Cyzicidae, Leptestheriidae, and Limnadiidae) are known from the neighboring regions of East Asia, including the Russian Far East, Mongolia, China, Korea, and Japan. The list of species and the key to the species are provided. Their distribution defines 4 zoogeographical provinces, and the species diversity clearly shows a latitudinal gradient in a similar pattern to the European fauna.
Jpn. J. Limnol., 60 : 585-606, 1999
A New Spinicaudatan (Crustacea: Branchiopoda)
from the Island of Olkhon (Lake Baikal, Russia)
and the Zoogeography of East Asian Spinicaudata
Hidetoshi NAGANAWA
ABSTRACT
A spinicaudatan branchiopod crustacean, Baikalolkhonia tatianae
gen. et sp. nov., is described from the Baikal region in Russia. The
genus is assigned to the family Cyzicidae STEBBING, 1910, based on the
absence of a frontal organ on the head, the absence of triangular
epipodal laminae on the thoracopods, and the presence of a pair of
large frontal spines on the telson. The main distinguishing characteris-
tic is that the epipodal upper corners of many anterior thoracopods
(including even the first pair) are transformed into "sausage-like
organs." Since such epipodal processes have been until now unknown
in the Cyzicidae, the diagnosis of the family is emended, and 2 newly
defined subfamilies, Baikalolkhoniinae and Cyzicinae, are proposed.
Up to the present, 11 species belonging to 7 genera in 4 families of
Spinicaudata (Cyclestheriidae, Cyzicidae, Leptestheriidae, and Lim-
nadiidae) are known from the neighboring regions of East Asia, includ-
ing the Russian Far East, Mongolia, China, Korea, and Japan. The list
of species and the key to the species are provided. Their distribution
defines 4 zoogeographical provinces, and the species diversity clearly
shows a latitudinal gradient in a similar pattern to the European fauna.
Key words : Baikalolkhoniinae, Lake Baikal, Spinicaudata, zoo-
geography
INTRODUCTION
The "Large Branchiopods" of the order Spinicaudata of the freshwater
fauna of Asia were partly treated by HU (1989). In total, 19 nominal species
are known from China (UENO, 1927b, 1940; ZHANG et al., 1976; HU, 1985-
1993 ; SHEN and DAI, 1987 ; SHU et al., 1990), including several synonymic
taxa (more details are given below in the section List of East Asian
Spinicaudata). Additional records are available from the rest of East Asia
(e.g., Japan: ISHIKAWA, 1895; UENO, 1927a; Mongolia: SARS, 1901 ; BRTEK
et al., 1984; Korea : YOON and KIM, 1992 ; Russian Far East : NAGANAWA
et al., 1996). According to the latest studies, the currently known
spinicaudatan fauna of East Asia consist of 11 valid species belonging to 7
genera in 4 families : Cyclestheriidae, Cyzicidae, Leptestheriidae, and
Limnadiidae.
586 NAGANAWA
The Cyzicidae STEBBING, 1910 is characterized by the absence of a frontal
organ on the head, the absence of a triangular epipodal lamina on the
thoracopods, and the presence of a pair of large frontal spines on the telson.
In addition, STEBBING (1910) based his family diagnosis on the absence of a
terminal spine on the rostrum and the unsegmented nature of the anten-
nules, but there is considerable diversity in the morphology of these struc-
tures within the Cyzicidae, and now a reassessment of the original diagnosis
is in order.
Since the Baikal specimens described below have no frontal organ on the
head, thoracopods without a triangular epipodal lamina, and a pair of large
frontal spines on the telson, they are therefore assigned to the Cyzicidae ;
moreover, the present species possesses a unique feature concerning
epipodal processes of the thoracopods, which warrants establishment of a
new genus. This genus is furthermore separated at the level of subfamily
from the other 2 closely related, currently recognized genera : Cyzicus
AUDOUIN, 1837 and Eocyzicus DADAY, 1913.
Order Spinicaudata LINDER,1945
Family Cyzicidae STEBBING, 1910
Baikalolkhonia gen. nov.
Diagnosis. - Female : Head with rounded occipital angle. Rostrum with a
spine-like process. Body formed of 20-23 limb-bearing trunk segments, the
number inconstant. Some posterior trunk segments provided dorsally with
well developed hooks bearing spines. Epipodal upper corners of several
anterior thoracopods, or almost all thoracopods, and always including the
first pair, transformed into "sausage-like organs." Exopodal upper corners of
the thoracopods not modified for bearing eggs. Telsonal spines unequally-
sized, very low in number.
Male : Unknown.
Type species. - Baikalolkhonia tatianae gen. et sp. nov.
Etymology. - The genus name is a latinized combination referring to the
type locality ("Baikal" + "Olkhon"). Gender feminine.
Baikalolkhonia tatianae gen. et sp. nov.
(Figs. 1-3)
Type Material. - Holotype •Š (960803-1) (3.4 mm carapace length),
deposited in the Zoological Museum at Irkutsk State University, Irkutsk,
Russia ; collected by H. NAGANAWA from a freshwater ephemeral pool on the
Island of Olkhon in Lake Baikal, Russia (53•‹04'N, 107•‹01'E), 3 August
1996. Paratypes 4•Š•Š(2.9•}0.1 mm) from type locality, in author's collec-
tion. Specimens are preserved in 80% ethanol with 1/10 volume of glycer-
ol.
587
New Prospect of East Asian Clam Shrimp Fauna
Fig.1. Baikalolkhonia tatianae gen. et sp. nov. (holotype female). (A) Carapace (left
side) ; (B) Same (dorsal view) ; (C) Whole animal (left side with left valve
removed, arrow [a] indicating flagella of biramous antenna ; see text for
further explanation); (D) Two of the dorsal processes of the trunk (left side).
Description.- Female : Carapace laterally compressed, oval quadrangular
in lateral view ; height about 3/5 of length ; dorsal margin nearly straight
(Fig.1A) ; ventral margin gently curved, anterior extremity bluntly trun-
cated, posterior one considerably expanded and broadly rounded (Fig. 1C) ;
umbo very small and placed far to front (Figs.1A, B). Valve thin and
pellucid, with 8-10 regularly arranged growth lines ; surface between lines
irregularly reticulated ; margins with minute hairs.
Body composed of 25 somites in holotype, distinctly divided into a head
(usually 2-segmented in Spinicaudata), 21 limb-bearing similar and 1
limbless trunk segments, and telson ; 6th to 19th trunk segments armed
dorsally with conical hooks, latter longer than width at base (Fig. 1C. Last
588 NAGANAWA
22nd trunk segment confluent with telson. Dorsal terga of anterior 5 trunk
segments without spines;dorsal processes of posterior trunk segments large,
with backwardly-directed long, strong spines (Fig. 1D), giving dorsal face an
imbricate appearance;left armature of spines in holotype :
Head 0.0.0.0.0. 3.3.5.5.6. 8.7.5.3.3. 3.3.3.2.1. 1.0. Telson. A pair of
dorsal processes per segment, with 1-8 spines per process.
Head narrowly rounded distally and with obtuse occipital prominence
(Fig.2A [b]) ; rostrum triangular and somewhat recurved, with some
spinules on the front and a well-marked apical terminal process (Figs.2A,
C). Two closely placed, sessile compound eyes located some distance from
ventral margin of head in lateral view (Figs. 2A-C). Ocellus, ventral to
eyes, triangular in lateral view and variable in shape (Figs.2A, C). Labrum
Fig. 2. Baikalolkhonia tatianae gen. et sp. nov. Holotype female : (A) Head (left
side, antennae omitted, arrows [b, c, d, and e] indicating occipital prominence,
spine-like rostral process, labrum (upper lip), and antennule, respectively ;
see text for further explanation) ; (B) Same (anterior) ; Paratype females :
(C) Head shape of two individuals (left side).
589
New Prospect of East Asian Clam Shrimp Fauna
(upper lip) developed, elongate backward, with setae confined to tip (Fig.
2A [d]).
Antennule arising from posterolateral surface of rostrum, distinctly seg-
mented, with several sensilla-bearing lobes (Fig.2A [e]).
Antenna large, well developed, biramous (Fig.1C). Peduncle with short
spines on anterior edge, divided into 2 poorly demarcated cylindrical seg-
ments ; proximal segment without distal setae ; distal segment wrinkled,
with a few short spines on anterior edge. Each biramous flagellum 9-seg-
mented (Fig.1C [a]) ; each segment bearing 1-4 short spines along anterior
edge and 3-4 longer, simple, distal setae on posterior edge.
Fig. 3. Baikalolkhonia tatianae gen. et sp. nov. (holotype female). (A) Left thoracopod
of 1st pair (outer side, arrow [f] indicating sausage-like epipodal organ) ; (B)
Left thoracopod of 7th pair (outer side, arrow [g] indicating sausage-like
epipodal organ) ; (C) Telson with caudal rami (left side, arrow [h] indicating
the large frontal spine, arrows [i, j] indicating larger telsonal spines, arrow [k]
indicating the left furcal spine) ; (D) Posterior part of trunk with caudal rami
(ventral view, arrows [1, m] indicating long, acute, bifid furcal spines on medial
surfaces of caudal rami ; [m] is identical with [k]). See text for further
explanation.
590 NAGANAWA
Twenty-one pairs of similar thoracopods in holotype, range among para-
types is 20-23, decreasing in size posteriorly (Fig.1C). Epipodal upper
corners of first 7 thoracopods (in holotype) each with sausage-like, cylindri-
cal process (Figs.1C, 3A [f] , B [g]). In paratypes, however, number of such
pairs varying (up to 20) among specimens of the same state of maturity,
always beginning with anteriormost pair.
Telson with a pair of long filaments and 7 pairs of spinulose, unequally-
sized spines, including a pair of large frontal spines (Fig. 3C [h], left frontal
spine); dorsal profile concave and leading to terminal projection ; telsonal
filaments long, plumose, arising from vicinity of second most anterior spine .
Caudal rami well developed ; distal half with a row of identical denticules,
fewer toward tip (Fig.3C) ; a long, acute, bifid spine on medial side (Figs.
3C [k], D [1, m] ; [m] is identical with [k]) .
Live specimens translucent, dominant color of valves yellow pale tending
toward orange.
Male : Unknown.
Etymology. -The species is named after the author's co-worker, Ms.
Tatiana I. ORGILJANOVA, who contributed greatly to the finding of this new
form.
Remarks. -The Baikal specimens may possibly not be fully mature ;
however, I believe enough key characters are present to differentiate the
taxon as a valid species (see NOTES ON TAXONOMY).
Ecological notes. -Up to the present, this species is known only from its
type locality, approximately 5 km from the island's Lake Baikal shoreline .
The pool had a surface area of about 400 m2 with an average depth of 30 cm .
The fresh water was pH 7.7 and remained constant around 25 •Ž in the
daytime in August. The accompanying fauna included several species of
branchiopods : an undescribed anostracan species (Chirocephalus sp .), an
unidentified notostracan Triops sp ., and some cladocerans.
Olkhon is the largest of 22 islands in Lake Baikal . It is 71.7 km long and
15 km wide, with an area of about 720 km2 . As recounted by GALAZIY
(1984), AFANASEV (1967) distinguished 5 climatic districts in the Baikal
region according to the annual precipitation : (1) North Baikal district
(north of Pokoyniki and Turka Rivers) -700 mm, (2) "Hamar-Daban"
district - 1145 mm, (3) Cisbaikal southwest district (between Angara and
Pokoyniki Rivers) - 475 mm , (4) Chikoysk taiga district - 555 mm, and (5)
"Selenga -Dauriya" district (the Selenga basin , excluding the Chikoysk
taiga) - 420 mm (GALAZIY, 1984). Exceptionally , on the Island of Olkhon
the annual precipitation is less than 200 mm . Because of the very low
precipitation and the many fine-weather days on the island (on average only
62.2 rainy days per year (GALAZIY
, 1984)), there is usually very little or no
surface water, and even in winter the snow cover sometimes evaporates
entirely. The southern and southwestern parts of Olkhon (including the type
591New Prospect of East Asian Clam Shrimp Fauna
locality of this species) are steppes, and they are the most arid places in the
Baikal region.
This is the first record of a spinicaudatan species from shallow aquatic
biotopes in the Baikal region.
NOTES ON TAXONOMY
Family taxon of Baikalolkhonia
According to the current system of spinicaudatan classification (STEBBING,
1910 ; DADAY, 1913, 1923 ; STRASKRABA, 1965a, 1965b, 1966 ; BELK, 1982 ;
FRYER, 1987; HU, 1989; BRTEK and THIERY, 1995), the new species
Baikalolkhonia tatianae is an intermediate form between the families
Cyzicidae STEBBING, 1910 and Leptestheriidae DADAY, 1923.
Until now, the sausage-like, cylindrical epipodal organs on the thoracopods
in females, which are usually adapted for bearing eggs, have been considered
as a unique, typical characteristic of leptestheriids, and they are unknown
among the other 3 spinicaudatan families (the Cyclestheriidae, Cyzicidae,
and Limnadiidae), with the single exception of the present species. How-
ever, there is an analogous feature common to these latter 3 families : the
exopodal upper corners of the thoracopods, including the 10th and some
vicinal pairs in females, are partly produced upward as elongate filaments
(not as lobes) adapted for bearing eggs.
In the Leptestheriidae the modified epipodal lobes start at the 10th pair of
thoracopods and continue to the 11th pair and beyond. In contrast, in
Baikalolkhonia tatianae the modified thoracopods begin more anteriorly,
including even the first pair without exception (Figs. 1C, 3A [f] , B [g]) , and
sometimes all pairs are involved (not shown in illustration).
STEBBING (1910) established the family Cyzicidae with Cyzicus AUDOUIN,
1837 as the proper type genus (based on Decision 54 of the International
Commission on Zoological Nomenclature, taken at the 14th International
Congress of Zoology at Copenhagen, 1953). The family characters as stated
by STEBBING (1910) were (a) "conchostracans" (now divided into two
independent orders : Spinicaudata and Laevicaudata ; FRYER, 1987)
enveloped by a bivalved carapace marked by numerous growth lines, (b) the
first and second post-cephalic appendages of the male modified into claspers,
(c) no frontal organ on the head, (d) unsegmented antennules, (e) no
terminal spine on rostrum, and (f) with a conspicuous, truncated telson (*
now a reassessment is in order ; more on this below).
Baikalolkhonia tatianae has a spine-like rostral process (Figs.2A [c] , B,
C) ; because the same process has also been observed in cyzicid females (e.
g., STRASKRABA, 1965b), it is not a valid character to separate the new
species from the Cyzicidae. In addition, a segmented type of antennule (Fig.
2A[e]) has also been drawn in some cyzicids, e.g., Cyzicus gifuensis
(ISHIKAWA, 1895) (syn. Caenestheriella gifuensis (ISHIKAWA)), Eocyzicus
davidi (SIMON, 1886), E. propinquus (SARS, 1901), and E. sahlbergi (SIMON,
1886). The large spine on the medial surface of each caudal ramus of the
592 NAGANAWA
Baikal specimens (Fig. 3C [k], D [l, m]) is similar to those of some cyzicids,
e.g., Cyzicus gifuensis, C. tetracerus (KRYNICKI, 1830) (in southern Slova-
kian specimens ; STRASKRABA, 1965b), and Eocyzicus orientalis DADAY,
1915 ; and the rounded occipital angle in the Baikal specimens (Fig. 2A [b] )
is also reminiscent of another genus, Eocyzicus, of the same family. The
large frontal spine on the telson (Fig. 3C [h]) and the unequally-sized
telsonal spines (Fig. 3C [i, j]) are characteristics common to many cyzicids.
Thus, while Baikalolkhonia tatianae is considered a member of the
cyzicids because it shares certain general characteristics with them ; it is a
form that seems to be related to leptestheriids because of the modified
epipods of thoracopods in the female.
Family Cyzicidae with proposal of 2 new subfamilies
The present species may be a "living fossil" close to the common ancestor
of the Cyzicidae and Leptestheriidae. We may assume two different lines of
evolution within the cyzicid group, namely one represented by the monotypic
new genus Baikalolkhonia, and the other represented by the closely related
genera Cyzicus and Eocyzicus. This can be indicated by considering the
group as a family with two subfamilies, defined as follows :
Family Cyzicidae STEBBING, 1910
Estheriidae SARS, 1900: 10 (invalid name).
Cyzicidae STEBBING, 1910: 486 ; BARNARD, 1929: 253-254 ; MATTOX, 1957a : 370 ;
BELK, 1982: 178 ; HU, 1989: 4 ; BRTEK and THIERY, 1995: 265-266.
Caenestheriidae DADAY, 1913: 66 ; 1915: 49 ; UENO, 1927a : 267 ; FORRO and BRTEK,
1984: 79, 85.
Diagnosis. - Carapace with numerous growth lines ; umbo distinct but
small. Head with prominent or rounded occipital angle ; a frontal organ
lacking. Fornices (a pair of anatomical folds on both sides of the head)
distinctly developed. Compound eyes divided, closely placed. Rostrum
usually without terminal spine, but in some females with a spine-like
process. Segmented type of antennules with several sensilla-bearing lobes.
Body formed of 15-26 limb-bearing trunk segments. Some posterior trunk
segments provided dorsally with rows of denticles, or with processes bearing
rows of setae and/or spines. Thoracopods without triangular epipodal
lamina. Telsonal spines various in size and number among species, a pair of
frontal spines developed. First two pairs of thoracopods modified as claspers
in male.
The family contains 2 subfamilies : Baikalolkhoniinae and Cyzicinae, each
newly defined as follows based on the presence or absence of epipodal
"sausage -like organs."
Baikalolkhoniinae subfam. nov.
593New Prospect of East Asian Clam Shrimp Fauna
Diagnosis. -Female : Head with rounded occipital angle. Rostrum with a
spine-like process. Body formed of 20-23 limb-bearing trunk segments.
Some posterior trunk segments provided dorsally with developed processes
bearing spines. Epipodal upper corners of several anterior thoracopods, or
almost all thoracopods, and always including the first pair, transformed into
"sausage -like organs." Exopodal upper corners of the thoracopods in female
unadapted for bearing eggs. Telsonal spines unequally-sized, very low in
number.
Male : Unknown.
The subfamily contains only genus : Baikalolkhonia gen. nov.
Distribution. -Baikal subregion (Island of Olkhon).
Cyzicinae subfam. nov.
Diagnosis. -Head with prominent or rounded occipital angle. Rostrum
without terminal spine, in some females with a spine-like process. Body
formed of 15-26 limb-bearing trunk segments, the number inconstant.
Some posterior trunk segments provided dorsally with rows of denticles, or
with hooks bearing setae and spines. All epipods of thoracopods without
"sausage -like organs." Exopodal upper corners of 9th and 10-11th tho-
racopods in female elongate, adapted for bearing eggs. Telsonal spines
unequally-sized, various in number depending on species.
The subfamily contains 2 genera : Cyzicus (syn. Estheria RUPPELL, 1837
[in part], Caenestheriella DADAY, 1913 [in part]), and Eocyzicus (syn.
Caenestheria DADAY, 1913 [in part]). The genera are not adequately
distinguished from each other. The only character currently judged to be
valid is the prominent (Cyzicus) or rounded (Eocyzicus) occipital angle of
the head.
Distribution.- Worldwide (except for Antarctica). Both genera are
known from East Asia.
List of East Asian Spinicaudata
Order Spinicaudata
Conchostraca SARS, 1867: 5-6; DADAY, 1913: 61 ; 1915: 39-47 ; 1923: 255 ; 1925 :
143 ; 1926: 1 ; 1927: 1 ; BARNARD, 1929: 242 ; MATTOX, 1957a : 367 ; 1959: 577-
580 ; ZHANG et al., 1976: 4-19 ; BELK, 1982: 178 ; HU, 1989: 1.
Spinicaudata LINDER, 1945: 1-28 ; FRYER, 1987: 368-374 ; BRTEK and THIERY, 1995 :
265-266.
Family Cyclestheriidae (1 species in East Asia)
Limnadiidae : SARS, 1888: 24 (in part).
Cyclestheriidae DADAY, 1913: 66-88 ; BARNARD, 1929: 248 ; BELK, 1982: 178 ; SHEN
and DAI, 1987: 353 ; HU, 1989: 2-3.
Paracyclestheria SHEN and DAI, 1987
594 NAGANAWA
Paracyclestheria SHEN and DAI, 1987: 353 ; HU, 1989: 3.
Paracyclestheria sinensis SHEN and DAI, 1987
Paracyclestheria sinensis SHEN and DAI, 1987: 353-356, figs. 1-9 ; HU, 1989: 3, figs. 8-
11.
Family Cyzicidae (5 species in East Asia)
Subfamily Baikalolkhoniinae subfam. nov.
Baikalolkhonia gen. nov.
Baikalolkhonia tatianae gen. et sp. nov.
Subfamily Cyzicinae subfam. nov.
Cyzicus AUDOUIN, 1837
Estheria RUPPELL, 1837 (in part) (invalid name) .
Cyzicus AUDOUIN, 1837: 9 ; DADAY, 1915: 232-235 ; MATTOX, 1957b : 206-209 ;
1958: 123 ; 1959: 583 ; STRASKRABA, 1965b : 210-212 ; UENO, 1967: 252 ; FORRO
and BRTEK, 1984: 89 ; HU, 1989: 5 ; BRTEK and THIERY, 1995: 265-266.
Caenestheriella DADAY, 1913 (in part).
Cyzicus gifuensis (ISHIKAWA, 1895) [Japanese name : Kaiebil
Estheria gifuensis ISHIKAWA, 1895: 10-12, pl. 4, figs. 1-12.
Caenestheriella gifuensis : DADAY, 1915: 124, fig. 22; UENO, 1927a: 267 ; YOON and
KIM, 1992: 474-479, figs. 2-4.
Cyzicus sinensis HU, 1988a: 52-58, figs. 1-13. Syn. nov.
Cyzicus gifuensis : SASSAMAN, 1995: 48.
Eocyzicus DADAY, 1913
Eocyzicus DADAY, 1913: 67-74 ; 1915: 190 ; BARNARD, 1929: 260 ; UENO, 1935: 15 ;
DURGA PRASAD et al., 1981: 195-203 ; BRTEK et al., 1984: 94-95 ; HU, 1985: 357 ;
1989: 4 ; 1992: 274; BRTEK and THIERY, 1995: 266.
Caenestheria DADAY, 1913 (in part) ; HU, 1989: 5 ; 1991: 111-114.
Eocyzicus davidi (SIMON, 1886)
Estheria davidi SIMON, 1886: 452 ; SARS, 1901: 152-153, pl. 6, figs. 1-14.
Caenestheria davidi : DADAY, 1915: 73-77, fig. 7 ; UENO, 1940: 98; ZHANG et al.,
1976: 24 ; HU, 1988b : 77 ; 1989: 5, pl. 1, figs. 54-60 ; 1991 : 111-112, pl. 2, figs.
23-27.
Caenestheriella kawamurai UENO, 1927a: 267-269, pl. 30, figs. 35, 35a-35i.
Eocyzicus mongolianus UENO, 1927b : 157-160, fig. 1 ; 1935: 15-16, pl. 4 ; ZHANG et
al., 1976: 24 ; BRTEK et al., 1984: 94-96 ; HU, 1985: 360; 1988b : 73, figs. 29-35 ;
1989: 4, figs. 29-35 ; 1991a: 69, fig. 1 ; 1993b: 55-56, figs. 6-14. Syn. nov.
Eocyzicus davidi : BRTEK et al., 1984: 94, figs. 17-25 ; HU, 1993b: 56-57, figs. 15-23.
Eocyzicus laiyangensis HU, 1985: 357-362, figs. 1-16; 1986: 24-25, figs. 1-8 ; 1988b:
73-74, figs. 36-42 ; 1989: 4-5, figs. 36-42 ; 1991a: 69, fig. 8 ; 1993b: 57-58, figs. 24-
595New Prospect of East Asian Clam Shrimp Fauna
31. Syn. nov.
Caenestheria kawamurai : HU, 1989: 5, figs. 61-66 ; 1991b: 111-112, figs. 1-5. Syn.
nov.
Caenestheria shiquanica HU, 1991b : 111-118, figs. 6-18 ; 1993a: 181-184, figs. 1-14.
Syn. nov.
Eocyzicus orientalis DADAY, 1915
Eocyzicus orientalis DADAY, 1915: 205-210, figs. 45, 46 ; UENO, 1927b : 158-160 ;
DURGA PRASAD et al., 1981: 199 ; FORRO and BRTEK, 1984: 79 ; HU, 1985: 357 ;
1988b: 72, figs. 21-28 ; 1989: 4 ; 1991a: 69 ; 1993b: 54-55, figs. 1-5 ; DOBRYNINA
and BRATNIK, 1989a : 49-51, fig. 2 ; 1989b : 144-150 ; BRTEK and THIERY, 1995: 266.
Eocyzicus yanzhouensis HU, 1992: 274-277, figs. 1-11 ; 1993b: 58-59, figs. 32-42.
Syn. nov.
Eocyzicus paralaiyangensis HU, 1992: 277-280, figs. 12-23 ; 1993b : 59-64, figs. 43-54.
Syn. nov.
Eocyzicus propinquus (SARS, 1901)
Estheria propinqua SARS, 1901 : 155-157, pl. 8, figs. 1-8.
Caenestheria propinqua : DADAY, 1915; HU, 1991b: 111-113, figs. 48-50.
Eocyzicus propinquus : BRTEK and THIERY, 1995: 266.
Family Leptestheriidae (3 species in East Asia)
Leptestheriidae DADAY, 1923: 255-258 ; UENO, 1927a: 267 ; BARNARD, 1929: 263-
264; MATTOX, 1959: 583; STRASKRABA, 1966: 571-589 ; ZHANG et al., 1976: 24 ;
BELK, 1982: 178-179; HU, 1986: 25; 1987:357; 1989: 5-6; BRTEK and THIERY,
1995: 266.
Eoleptestheria DADAY, 1923
Eoleptestheria DADAY, 1923: 258-260 ; ZHANG et al., 1976: 24 ; HU, 1986: 25 ; 1987 :
357; 1989: 7 ; BRTEK and THIERY, 1995: 266.
Eoleptestheria ticinensis (BALSAMO-CRIVELLI, 1859)
Isaura ticinensis BALSAMO-CRIVELLI, 1859: 115, pl. 1.
Eoleptestheria ticinensis : DADAY, 1913: 95, fig. 8a-o ; 1923: 263, fig. 82a-q ; STRAS
KRABA, 1966: 578-584, figs. 4-7 ; BRTEK and THIERY, 1995: 266.
Eoleptestheria inopinata DADAY, 1923: 262, fig. 81a-i.
Eoleptestheria chinensis DADAY, 1923: 269-273, fig. 83a-q; UENO, 1940: 99-100, figs.
21-28 ; ROEN, 1952: 212, fig. 19; ZHANG et al., 1976: 24 ; HU, 1989: 7, figs. 92-98.
Eoleptestheria variabilis BOTNARIUC, 1947: 82, pls. 1, 2, 4, 5, figs. 2, 3.
Eoleptestheria spinosa MARINCEK, 1978: 103-118.
Eoleptestheria spinosa tenuis MARINCEK and VALVAJTER, 1979: 155-167.
Eoleptestheria spinosa magna MARINCEK and VALVAJTER, 1982: 63-72.
Eoleptestheria spinosa mira MARINCEK and PETROV, 1983: 89-103.
Eoleptestheria dongpingensis HU, 1986: 25-27, figs. 9-23 ; 1987: 341-347, figs. 1-15 ;
1989: 7, figs. 99-109. Syn. nov.
Eoleptestheria yanchowensis SHU et al., 1990: 410-416, figs. 1-21. Syn. nov.
596 NAGANAWA
Leptestheria SARS, 1898
Leptestheria SARS, 1898: 23 ; 1900: 10; STEBBING, 1910: 488 ; DADAY, 1913: 80 ;
1923: 273-276 ; UENO, 1927a: 269 ; BARNARD, 1929: 264; MATTOX, 1959: 583 ;
ZHANG et al., 1976: 24 ; HU, 1987: 357 ; 1989: 6 ; BRTEK and THIERY, 1995: 266.
Leptestheriella DADAY, 1923 (in part).
Leptestheria dahalacensis (RUPPELL, 1837)
Estheria dahalacensis RUPPELL, 1837: 119, pl. 7a, b.
Isaura dahalacensis : JOLY, 1842: 341.
Estheria pesthinensis BRUHL, 1860 ; CHYZER, 1861: 115, pl. 3, figs. 1-4.
Leptestheria tenuis SARS, 1901: 157-158, pl. 8, figs. 9-17 ; DADAY, 1923: 319-324, fig.
95 ; UENO, 1940: 98-99 ; 1967: 24 ; HU, 1989: 6, figs. 67-72.
Leptestheria dahalacensis : KEILHACK, 1909: 182 ; DADAY, 1913: 106, figs. 10a-m,
11a-1; 1923: 337, figs. 99a-m, 100a-o; STRASKRABA, 1966: 571-578, figs. 1-4.
Leptestheria rotundirostris DADAY, 1913: 102, fig. 9a-p ; 1923: 329, fig. 97a-p.
Leptestheria lybica COLOSI, 1920: 120 ; 1923: 292.
Leptestheria aegyptiaca DADAY, 1923: 333, fig. 98a-o.
Leptestheria dives DADAY, 1923: 345, figs. 101a-h, 102a-i.
Leptestheria intermedia BOTNARIUC, 1947: 88, pl. 1, figs. 5-6, p1. 2, figs. 3, 4, pl. 6a-p.
Leptestheria dives var. securiformis BOTNARIUC, 1947: 90, pl. 7a-n.
Leptestheria xinjiangensis HU, 1987: 357-361, figs. 1-15 ; 1989: 6, figs. 83-91. Syn.
nov.
Leptestheria kawachiensis UENO, 1927 [Japanese name: Togekaiebi]
Leptestheria kawachiensis UENO, 1927a: 269-270, pl. 31, figs. 36, 36a-n; HU, 1989: 6,
figs. 73-77.
Leptestheria nanjingensis ZHANG et al., 1976: 25-26, fig. 30; HU, 1989: 6, figs. 78-82 .
Syn. nov.
Family Limnadiidae (3 species in East Asia)
Limnadiidae BURMEISTER, 1843 (in part) ; SARS, 1896: 84; DADAY
, 1913: 66-84;
1915: 113 ; 1925: 143 ; UENO, 1927a : 270 ; BARNARD, 1929: 250 ; STRASKRABA
,
1965a : 263 ; BELK, 1982: 179 ; HU, 1989: 3-4 ; BRTEK and THIERY, 1995: 266.
Subfamily Limnadiinae BURMEISTER, 1843
Limnadiinae : STRASKRABA, 1965a: 269.
Eulimnadia PACKARD, 1874
Eulimnadia PACKARD, 1874; ISHIKAWA, 1895: 15-20; SARS
, 1896: 8 ; DADAY, 1913:
84-85 ; UENO ; 1927a : 270-271 ; MATTOX, 1937: 249 ; 1939: 642 ; 1953: 57 ;
1954: 3 ; 1959: 581 ; STRASKRABA, 1965a: 271 ; HU, 1986: 27; 1989: 3-4; BELK,
1989: 115-125.
Eulimnadia braueriana ISHIKAWA, 1895 [Japanese name : Hime-
kaiebil
Eulimnadia braueriana ISHIKAwA , 1895: 15-19, p1.8, figs. 1-9; DADAY, 1926: 27-30,
597
New Prospect of East Asian Clam Shrimp Fauna
figs. 132a-o ; UENO, 1927a: 271.
Eulimandia packardiana ISHIKAWA, 1895: 19-20, pl. 7, figs. 1-5 ; DADAY, 1926: 20-22,
figs. 130a-c; UENO, 1927a: 271. Syn. nov.
Eulimandia taoluoensis HU, 1986: 27-28, figs. 24-30 ; 1989: 4, figs. 17-20. Syn. nov.
Eulimnadia kobai UENO, 1940
Eulimnadia kobai UENO, 1940: 97, figs. 16-20; HU, 1989: 3, figs. 12-16.
Limnadia BRONGNIART, 1820
Limnadia BRONGNIART, 1820: 84.
Limnadia lenticularis (LINNAEUS, 1761) [Japanese name : Usuhime-
kaiebi]
Monoculus lenticularis LINNAEUS, 1761 : 499.
Daphnia gigas HERMANN, 1804: 134, p1. 5, figs. 4, 5.
Limnadia hermanni BRONGNIART, 1820: 84, pl. 13.
Limnadia gigas : GRUBE, 1853: 154, pl. 8, figs. 9-11.
Limnadia lenticularis : SAHLBERG, 1875: 317 ; SARS, 1896: 85, pls. 14-17 ; DADAY,
1925: 158, fig. 117; STRASKRABA, 1965a: 263-266, figs. 1-4; BRTEK and THIERY ,
1995: 266.
Limnadia americana MORSE, 1866-1868: 404.
Limnadia nipponica ISHIKAWA, 1895: 13-15, pl. 7, figs. 6-10; DADAY, 1925: 155, fig.
116.
Key to East Asian Spinicaudata
*. Carapace bilaterally compressed, enclosing the head and trunk , usually
with growth lines. Posterior trunk segments with rows of denticles
dorsally, or with a pair of rows of processes, bearing setae and/or spines.
Telson massive, armed dorsally with spines or denticles, and with a pair
of caudal rami. More than 12 pairs of thoracopods (up to 32)
•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c Order Spinicaudata
1. Head with frontal organ, carapace partly with growth lines . Umbo
lacking. Head with rounded occipital angle .......... Family Limnadiida
e Subfamily Limnadiinae•c•c4
•\ Head lacking frontal organ •c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c2
2. Carapace with rudimentary growth lines antero-dorsolaterally . Fornices
undeveloped. Compound eyes fused into one structure. Antennules
bar-shaped, unsegmented, lacking sensilla-bearing lobes. Only first pair
of thoracopods modified as claspers in male. Body with 13-14 pairs of
thoracopods•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•cFamily Cyclestheriidae
Genus Paracyclestheria
Paracyclestheria sinensis
•\ Carapace with numerous growth lines. Fornices distinctly developed .
Compound eyes divided, closely placed. Segmented type of antennules
with several sensilla-bearing lobes. First two pairs of thoracopods
598 NAGANAWA
modified as claspers in male•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c3
3. Rostrum armed with permanent terminal spine in both sexes. All tho-
racopods with triangular epipodal lamina. Frontal spine on telson un-
developed •c•c•c•c•c•c•c•c•c•c•c•c•c•c•cFamily Leptestheriidae•c•c6
•\ Rostrum lacking terminal spine. Thoracopods without triangular epipodal
lamina. Frontal spine on telson highly developed
•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c Family Cyzicidae •c•c•c8
4. Telsonal hind-corner prominent•c•c•c•c•c•c•c•c•cGenus Eulimnadia•c•c5
•\ Telsonal hind-corner rounded •c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•cGenus Limnadia
Limnadia lenticularis
5. Frontal organ pyriform. Rostrum truncated. Antennal flagella 7-8 seg-
mented •c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•cEulimnadia braueriana
•\ Frontal organ very large, fan-shaped in lateral view. Rostrum promi-
nent. Antennal flagella about 17 segments •c•c•c•c•c•c•c Eulimnadia kobai
6. Head with rounded occipital angle•c•c•c•c•c•c•c•c•c•cGenus Eoleptestheria
Eoleptestheria ticinensis•\
Head with prominent occipital angle Genus Leptestheria•c•c7
7. Posterior trunk segments dorsally with rows of short denticles
•c•c•c•c•c•c•c Leptestheria dahalacensis•\
Posterior trunk segments dorsally with developed processes bearing 1-2
spines on top•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•cLeptestheria kawachiensis
8. Epipodal upper corners of anterior thoracopods in female with "sausage-
like organs" •c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•cSubfamily Baikalolkhoniinae
Genus Baikalolkhonia gen. nov.
Baikalolkhonia tatianae gen. et sp. nov.
•\ Epipodal upper corners in female without "sausage-like organs"
•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c Subfamily Cyzicinae •c•c•c9
9. Head with prominent occipital angle •c•c•c•c•c•c•c•c•c•c•c•c•c•c Genus Cyzicus
Cyzicus gifuensis•\
Head with rounded occipital angle•c•c•c•c•c•c•c•c•cGenus Eocyzicus•c•c•c•c•c•c10
10. Body with about 15 pairs of thoracopods•c•c•c•c•cEocyzicus propinquus
•\ Body with 20-26 pairs of thoracopods •c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c11
11. Posterior trunk segments dorsally with developed processes bearing
many unequally-sized setae and spines •c•c•c•c•c•c•c•c•c•cEocyzicus davidi
•\ Posterior trunk segments dorsally with rows of 1-5 acute, similar spines
posteriorly •c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•c•cEocyzicus orientalis
Zoogeographical aspects of East Asian Spinicaudata
I follow basically BELK's (1982) synopsis and classification , FRYER'S
(1987) new classification system, and BRTEK and THIERY's (1995) checklist,
with 2 additional valid genera (Cyclestheriidae : Paracyclestheria SHEN and
DAI, 1987 and Cyzicidae : Baikalolkhonia gen . nov.). From East Asia 12
species listed above, belonging to 8 genera in 4 families , are valid. The
geographic distribution of the species is mapped in Figure 4. Species diver-
sity was measured by counting the species occurring in intervals of 5 degrees
of north latitude (after BRTEK and THIERY'S (1995) method), and is illus-
599New Prospect of East Asian Clam Shrimp Fauna
Fig.4. Distribution patterns of East Asian spinicaudatan species : Cyclestheriidae
(diamond), Cyzicidae (triangles), Leptestheriidae (squares), and Limnadiidae
(circles). X, Y, and Z indicating endemic species ; broken lines are zoogeo-
graphical boundaries : (1) "Baikal-Olkhon" elements, (2) Palaearctic elements,
(3) Oriental elements, (4) "Far Eastern" elements ; compare the two dis-
tributional densities of spinicaudatans on the Asian Continent and in the
Japanese Islands. See text for further explanation.
Fig. 5. Relationship between species diversity and latitude for Spinicaudata of East
Asia and Europe. The spinicaudatans of East Asia show a clear diversity
gradient (striped) similar to the pattern of European fauna (open) (the graphic
method and data on the European fauna after BRTEK and THIERY, 1995).
600 NAGANAWA
trated in Figure 5, compared with that of the European fauna.
In the East Asian fauna (12 spp.) (Fig.4) the following 4 elements may
be recognized (# endemic species in East Asia) :
1. "Baikal-Olkhon" elements (1 sp.) : # Baikalolkhonia tatianae.
2. Palaearctic elements (7 spp.) : Eocyzicus davidi, Eocyzicus orientalis,
Eocyzicus propinquus, Eoleptestheria ticinensis, Leptestheria dahalacen-
sis, # Eulimnadia kobai, and (Holarctic) Limnadia lenticularis.
3. Oriental elements (1 sp.) : # Paracyclestheria sinensis.
4. "Far Eastern" elements (3 spp.) : Cyzicus gifuensis, Leptestheria kawa-
chiensis, and Eulimnadia braueriana.
Baikalolkhonia tatianae is known only from its type locality.
Most palaearctic elements of the East Asian fauna are wide-ranging
species ; for Eocyzicus orientalis, Eocyzicus propinquus, Eoleptestheria
ticinensis, and Leptestheria dahalacensis, the westernmost limits reach
Central Asia, Asia Minor, and even Europe. The range of Eocyzicus davidi
is restricted to East Asia. The origin of the point-endemic species Eulim-
nadia kobai deserves further consideration. Holarctic Limnadia lenticularis
is considered a northern component of the European and North American
faunas (40-60•‹N). In the basins of the Yellow and Yangtze Rivers, the Far
Eastern elements are partly coexistent with some palaearctic species.
Until now most Japanese freshwater biologists seem to have held the idea
for many years only from old literature (e.g., UENO, 1927a) that Japan has
a completely endemic, yet diverse, clam shrimp fauna. A Czechoslovakian
clam shrimp researcher STRASKRABA (1965a) for the first time discredited
that long-held idea. In recent years Chinese and Korean workers have made
an additional valuable contribution to clam shrimp studies (e.g., ZHANG et
al., 1976 ; HU, 1985-1993 ; YOON and KIM, 1992), and many taxonomic and
biogeographical questions are nearing a solution. Thus, all Japanese
spinicaudatan species are obviously not endemic to Japan, but are common
to East Asia.
A further study by our group on taxonomic and biogeographical aspects of
the East Asian fairy shrimp (Branchiopoda : Anostraca) fauna is in progress.
ACKNOWLEDGMENTS
Special thanks are due to my colleagues Prof. B. I. PISARSKY and Dr. A. I.
ORGILJANOV (Institute of the Earth's Crust, Siberian Division of Russian
Academy of Sciences [SD RAS]), to Mrs. L. V. ORGILJANOVA and G. I.
NAGORNAYA (Irkutsk, Russia), to Drs. N. A. BONDARENKO and N. G. MELNIK
(Limnological Institute SD RAS), and to my late father K. NAGANAWA for
their support. I also express my gratitude to Prof. HU WEIXING (Ocean
University of Qingdao, China) for providing useful information on Chinese
spinicaudatans.
601
New Prospect of East Asian Clam Shrimp Fauna
REFERENCES
AFANASEV, A. N. (1967) : Osccillation of hydrometeorological regime in the
territory of USSR (particularly in the Baikal basin), Nauka, Moscow (in
Russian).
AUDOUIN, M. V. (1837) : Seance du ler fevrier 1837. Ann. Soc. Entomol. Fr., 6 :
9-11.
BARNARD, K. H. (1929) : Contributions to the crustacean fauna of South Africa.
No. 10. Revision of the Branchiopoda. Order 3. Conchostraca. Ann. S. Afr.
Mus., 29 : 181-272.
BELK, D. (1982) : Branchiopoda. In Synopsis and Classification of Living
Organisms, Vol. 2, S. P. PARKER (ed.) : 174-180. McGraw-Hill Book Co.,
Inc., New York.
BELK, D. (1989) : Identification of species in the conchostracan genus Eulimnadia
by egg shell morphology. J. Crust. Biol., 9 : 115-125.
BOTNARIUC, N. (1947) : Contribution a la connaissance des Phyllopodes Concho-
straces de Roumanie. Notat. Biol., 5 : 68-158.
BRONGNIART, A. (1820) : Memoire sur le Limnadia, nouveau genre des Crustaces.
Mem. Mus. Hist. Nat. Paris, 6 : 83-93.
BRTEK, J., L. FORRO and J. E. PONYI (1984) : Contributions to the knowledge of
the Branchiopoda (Crustacea) fauna of Mongolia. Ann. Hist.-Nat. Mus. Natl.
Hung., 76 : 91-99.
BRTEK, J. and A. THIERY (1995) : The geographic distribution of the European
branchiopods (Anostraca, Notostraca, Spinicaudata, Laevicaudata).
Hydrobiologia, 298 : 263-280.
BRUHL in CHYZER, C. (1861) : Berichtungen and Erganzungen zu meiner Abhand-
lung : Uber die Crustaceenfauna Ungarns, insbesondere die dort angegebenen
Phyllopoden. Verb. Zool.-Bot. Ges. Wien, 11 : 111-120.
COLOSI, G. (1920) : Contributo alla conoscenza degli Entomostraci libici. Monit.
Zool. Ital., 31(7) : 120-124 (in Italian).
COLOSI, G. (1923) : Note supra alcuni Eufilopodi. Atti Soc. Ital. Sci. Nat., 61:
287- 297 (in Italian).
DADAY, E. (1913) : Magyarorszag kagylos levellabu rakjai (Phyllopoda Concho-
straca Hungariae). Magyar Tudom. Akad. Math. Termeszettud. Kozlem.,
32: 49-145 (in Hungarian).
DADAY, E. (1915) : Monographie systematique des Phyllopodes Conchostraces.
Premiere partie. Ann. Sci. Nat., Ser. 9, Zool. Paleontol., 20 : 39-330.
DADAY, E. (1923) : Monographie systematique des Phyllopodes Conchostraces.
Deuxieme partie. Ann. Sci. Nat., Ser. 10, Zool., 6 : 255-390.
DADAY, E. (1925) : Monographie systematique des Phyllopodes Conchostraces.
Troisieme partie. Ann. Sci. Nat., Ser. 10, Zool., 8 : 143-184.
DADAY, E. (1926) : Monographie systematique des Phyllopodes Conchostraces.
Troisieme partie (Suite). Ann. Sci. Nat., Ser. 10, Zool., 9 : 1-81.
DADAY, E. (1927) : Monographie systematique des Phyllopodes Conchostraces.
Troisieme partie (Fin). Ann. Sci. Nat., Ser. 10, Zool., 10 : 1-112.
DOBRYNINA, T. I. and R. Ya. BRATNIK (1989a) : Phyllopod crustaceans (Concho-
straca) of USSR fish-raising industries. Inf. Bull., 83 : 48-53 (in Russian).
DOBRYNINA, T. I. and R. Ya. BRATNIK (1989b) : Influences of temperatures on the
602 NAGANAWA
embryonic development of Eocyzicus orientalis DADAY (Branchiopoda, Con-
chostraca). Trans. Inst. Inland-Water Biol., USSR Acad. Sci., 56 : 144-150
(in Russian).
DURGA PRASAD, M. K., Y. RADHAKRISHNA, A. N. KHALAF and A. R. AL-JAAFERY
(1981) : Eocyzicus spinifer sp. nov. (Conchostraca : Cyzicidae) from Iraq.
Hydrobiologia, 78: 195-203.
FORR6, L. and J. BRTEK (1984) : Anostraca and Conchostraca taxa described by E.
DADAY together with a catalogue of pertinent material in the HUngarian
Natural History Museum. Misc. Zool. HUng., 2 : 75-104.
FRYER, G. (1987) : A new classification of the branchiopod Crustacea. Zool. J.
Linn. Soc., 91 : 357-383.
GALAZIY, G. I. (1984) : Baikal in Questions and Answers, East-Siberian Publish-
ing House, Irkutsk (in Russian).
GRUBE, A. E. (1853) : Bemerkungen uber die Phyllopoden, nebst einer Ubersicht
ihrer Gattungen and Arten. Arch. Naturg., 19 : 75-162.
HERMANN, J. F. (1804) : Memoire apterologique, Vol. 4, Strasbourg.
HU, W.-X. (1985) : A new species of Conchostraca (Crustacea : Conchostraca,
Cyzicidae) from Shandong Province, China. Acta Zootax. Sinica, 10 : 357-
362 (in Chinese).
HU, W.-X. (1986) : Studies of clam shrimps (Crustacea : Conchostraca). I. Three
species of Conchostraca in Shandong Province China. J. Shandong Coll.
Oceanol., 16(4) : 24-35 (in Chinese).
HU, W.-X. (1987) : A new species of Conchostraca (Crustacea : Conchostraca,
Leptestheriidae) from Xinjian, China. Acta Zootax. Sinica, 12 : 357-361 (in
Chinese).
HU, W.-X. (1988a) : A new species of Conchostraca (Crustacea : Conchostraca,
Cyzicidae) from AnHUi Province, China. J. Ocean Univ. Qingdao, 18 : 52-58
(in Chinese).
HU
, W.-X. (1988b) : Studies of clam shrimps (Crustacea : Conchostraca). II.
Sixteen species of Conchostraca in China. J. Ocean Univ. Qingdao, 18: 66-86
(in Chinese).
HU
, W.-X. (1989) : Taxonomic studies of Chinese conchostracan (Crustacea :
Eubranchiopoda). J. Ocean Univ. Qingdao, 19 : 1-11 (in Chinese).
HU
, W.-X. (1991a) : Recent cyzicid crustaceans of China. In Zoological Head-
line : 65-69. Beijing Educ. Univ. Press., Beijing (in Chinese).
HU
, W.-X. (1991b) : A taxonomic study on the living species of the genus
Caenestheria DADAY, 1914 (Crustacea : Conchostraca, Cyzicidae). J. Ocean
Univ. Qingdao, 21 : 111-118.
HU, W.-X. (1992) : Two new species of the genus Eocyzicus DADAY from Shan-
dong Province, China (Crustacea: Conchostraca, Cyzicidae). Acta Zootax.
Sinica, 17 : 274-282 (in Chinese).
HU, W.-X. (1993a) : A new species of the genus Caenestheria DADAY (Crustacea :
Conchostraca, Cyzicidae) from Shandong Province, China. Acta Hydrobiol.
Sinica, 17 : 181-184 (in Chinese).
HU, W.-X. (1993b) : Studies of clam shrimps (Crustacea : Conchostraca). III. Six
species of the genus Eocyzicus in China. J. Ocean Univ. Qingdao, 23 (4) : 53-
66.
ISHIKAWA, C. (1895) : Phyllopod Crustacea of Japan. Zool. Mag. , 7(78) : 8-21,
603
New Prospect of East Asian Clam Shrimp Fauna
pls. 4, 5, 7, 8.
JOLY, M. N. (1842) : Recherches zoologiques, anatomiques et physiologiques sur
l'Isaura cycladoides, nouveau genre de Crustace a test bivalve, decouvert aux
environs de Toulouse. Ann. Sci. Nat. Zool., Ser. 2, 17: 293-349.
KEILHACK, L. (1909): Phyllopoda. In Die Susswasserfauna Deutschlands, Vol.
10, F. BRAVER (ed.). Jena.
LINDER, F. (1945): Affinities within the Branchiopoda, with notes on some
dubious fossils. Ark. Zool., 37A (4): 1-28, 10 pls.
LINNAEUS, C. (1761): Fauna Suecica, 2nd ed., Stockholm.
MARINCEK, M. (1978): Eoleptestheria spinosa, a new species of Conchostraca
(Phyllopoda) discovered in Yugoslavia. Bull. Mus. Hist. Nat. Belgrade, B33:
103-118.
MARINCEK, M. and B. VALVAJTER (1979) : Eoleptestheria spinosa tenuis, a new
subspecies of Conchostraca (Phyllopoda) found in Yugoslavia. Bull. Mus.
Hist. Nat. Belgrade, B34 : 155-167.
MARINCEK, M. and B. VALVAJTER (1982) : Eoleptestheria spinosa magna, a new
subspecies of Conchostraca (Crustacea). Bull. Mus. Hist. Nat. Belgrade,
B37: 63-72.
MARINCEK, M. and B. PETROV (1983) : Eoleptestheria spinosa mica, a new sub-
species of Conchostraca (Crustacea). Bull. Mus. Hist. Nat. Belgrade, B38
89-103.
MATTOX, N. T. (1937) : Studies on the life history of a new species of fairy
shrimp, Eulimnadia diversa. Trans. Am. Microsc. Soc., 56 : 249-255.
MATTOX, N. T. (1939) : Description of two new species of the genus Eulimnadia
and notes on the other Phyllopoda of Illinois. Am. Midl. Nat., 22 : 642-653.
MATTOX, N. T. (1953) : Two new species of Eulimnadia from Maryland and
Virginia (Crustacea : Conchostraca). J. Wash. Acad. Sci., 43 : 57-60.
MATTOX, N. T. (1954) : A new Eulimnadia from the rice fields of Arkansas with
a key to the American species of the genus. Tulane Stud. Zool., 2 : 3-10.
MATTOX, N. T. (1957a) : A new estheriid conchostracan with a review of the other
North American forms. Am. Midl. Nat., 58 : 367-377.
MATTOX, N. T. (1957b) : Proposed addition of the name "Cyzicus" AUDOUIN, 1837
(Class Crustacea, Order Conchostraca) to the "official list of generic names on
Zoology" and matters incidental thereto. Bull. Zool. Nomencl., 13 : 206-209.
MATTOX, N. T. (1958) : Notes on the distribution of conchostracans in California.
Bull. S. Calif. Acad. Sci., 57 : 122-125.
MATTOX, N. T. (1959) : Conchostraca. In Fresh-Water Biology, 2nd ed., H. B.
WARD, G. C. WHIPPLE and W. T. EDMONDSON (eds.) : 577-586. John Wiley &
Sons, Inc., New York.
MORSE, E. S. (1866/68) : On Limnadia americana. Proc. Bost. Soc. Nat. Hist.,
11 : 404.
NAGANAWA, H., T. I. ORGILJANOVA, A. I. ORGILJANOV and B. I. PISARSKY (1996)
First record of the primitive crustacean groups (Branchiopoda, Anostraca ;
Notostraca ; Conchostraca) from the Island of Olkhon, Lake Baikal in Russia.
Aquabiology, 18 : 462-469 (in Japanese with English summary).
PACKARD, A. S., Jr. (1874) : Synopsis of the freshwater Phyllopod Crustacea of
North America. Ann Rept. U. S. Geol. Surv. Terr. (HAYDEN Survey), 7 :
613-622.
604 NAGANAWA
RpEN, U. (1952) : On some Euphyllopoda from North China. Vidensk. Medd.
Dansk. Naturh. Foren., 114 : 203-215.
RUPPELL, E. in STRAUS-DURCHHEIM, H. (1837) : Uber Estheria dahalacensis
RUPPELL, neue Gattung aus der Familia der Daphniden. Abh. Senckenb. Mus.,
2 : 117-128.
SAHLBERG, J. R. (1875) : Om Finlands hiltilskanda Phyllopoder och aterfinn an
det at Linnes Monoculus lenticularis. Not. Fauna Flora Fenn., n. ser., 11 :
317-325 (in Finnish).
SARS, G. O. (1867) : Histoire naturelle des Crustaces d'eau douce de Norvege,
Premiere livraison. Les Malacostraces, Johnsen, Christiania.
SARS, G. O. (1888) : On Cyclestheria hislopi (BAIRD), a new generic type of
bivalve Phyllopoda ; raised from dried Australian mud. Norske Vidensk.
Selsk. Forhand. aar, 1887 : 1-65.
SARS, G. O. (1896) : Fauna Norvegiae, Vol. 1. Phyllocarida og Phyllopoda
(Description of the Norwegian species at present known belonging to the
suborders Phyllocarida and Phyllopoda), Joint Stock Printing Co., Christia-
nia (in Norwegian).
SARS, G. O. (1897) : The Phyllopoda of the Jana-Expedition. Ann. Mus. Zool.
Acad. Imp. Sci. St.-Petersb., 2 : 463-493.
SARS, G. O. (1898) : On some South-African Phyllopoda raised from dried mud.
Arch. Math. Naturvidensk., Kristiania, 20(4) : 1-43.
SARS, G. O. (1900) : On some Indian Phyllopoda. Arch. Math. Naturvidensk.,
Kristiania, 22(9) : 1-30.
SARS, G. O. (1901) : On the crustacean fauna of Central Asia. Part I. Amphipoda
and Phyllopoda. Ann. Mus. Zool. Acad. Imp. Sci. St.-Petersb., 6 : 130-164.
SASSAMAN, C. (1995) : Sex determination and evolution of unisexuality in the
Conchostraca. Hydrobiologia, 298 : 45-65.
SHEN, C.-J. and A.-Y. DAI (1987) : A new and rare species of Conchostraca from
Yunnan Province, China (Crustacea : Conchostraca). Acta Zootax. Sinica,
12 : 353-356 (in Chinese).
SHU, Y.-F., M.-S. HAN and Z.-S. LIu (1990) : A new species of the genus
Eoleptestheria from Shandong, China (Crustacea : Conchostraca). Acta
Zootax. Sinica, 15 : 410-416 (in Chinese).
SIMON, E. (1886) : Etude sur les Crustaces du sous-ordre des Phyllopodes. Ann.
Soc. Entomol. Fr., Ser. 6, 6 : 393-460, 3 pls.
STEBBING, T. R. R. (1910) : General catalogue of South African Crustacea. Ann.
S. Afr. Mus., 6: 281-599.
STRASKRABA, M. (1965a) : Taxonomic studies on Czechoslovak Conchostraca, 1.
Family Limnadiidae. Crustaceana, 9 : 263-273.
STRASKRABA, M. (1965b) : Taxonomical studies on Czechoslovac Conchostraca, II.
Families Lynceidae and Cyzicidae. Acta Soc. Zool. Bohemoslov., 29 : 205-
214.
STRASKRABA, M. (1966) : Taxonomical studies on Czechoslovak Conchostraca. III,
Family Leptestheriidae, with some remarks on the variability and distribu-
tion of Conchostraca and a key to the Middle-European species.
Hydrobiologia, 27: 571-589.
UENO, M. (1927a) : The freshwater Branchiopoda of Japan 1. Mem. Coll. Sci.
Kyoto Imp. Univ., Ser. B,2 : 259-311, pls. 21-31.
605
New Prospect of East Asian Clam Shrimp Fauna
UENO, M. (1927b) : On some freshwater. branchiopods from China. Annot. Zool.
Japon., 11 : 157-163.
UENO, M. (1935) : Crustacea of Johol. Order Phyllopoda. In Report of the First
Scientific Expedition to Manchoukuo, Sec. V, Div. 1, Part II, Article 6 : 1-16.
UENO, M. (1940) : Phyllopod Crustacea of Manchoukuo. Bull. Biogeogr. Soc.
Jpn., 10(5) : 87-102.
UENO, M. (1967) : Two new species of Conchostraca (Branchiopoda) from Nepal
and Iran. Crustaceana, 13 : 249-256.
YOON, S. M. and W. Kim (1992) : A taxonomic study on the Recent concho-
stracans of Spinicaudata (Crustacea, Branchiopoda) from Korea. Korean J.
Zool., 35 : 474-483.
ZHANG, W.-T., P.-J. CHEN and Y.-B. SHEN (1976) : Fossil Conchostraca of China,
Science Press, Beijing (in Chinese).
Hidetoshi NAGANAWA : c/o Prof. Dr. Boris I. Pisarsky, Institute of the Earth's
Crust, Siberian Division of Russian Academy of Sciences, Irkutsk 664033,
Russia ; Domestic address (for correspondence), Daifukucho 5-13-442,
Gifu-shi,Gifu 502-0934,Japan(長 俊:ロ ー(シ
部)地 殻 研 究 所 客 員 研 究 員;〔 国 内 連 絡 先 〒502-0934岐 市 大 福 町5-13-
442)
(Received : 19 October 1998 ; Accepted : 29 July 1999)
606 NAGANAWA
バ イ カル湖 オ リホ ン島 か ら初 めい だ され
鰓 脚 甲殻類(カ 目)お
ジア 産 カ 動 物地 理
長縄秀
摘 要
イ カ ル 湖 ン 島 の 小 水 域 ら れ た 大 鰓 脚 甲 殻 類(カ イ エ 目)の1種
Baikalolkhonia tatianae gen. et sp. nov.(バ ルホ ニ 新 種)と
記 載 した 。 本 属 は,前 額 部 付 属 器 び 全 鰓 脚 に 上 肢 三 角 板 を そ れ ぞ れ 欠 き,尾
に1対 な前 き,科Cyzicidae STEBBING,1910(カ ビ科)
に属 す と判 断 れ た 本 属 固有 の 主 な分 類 学 的特 徴 は,第1脚 を含 む 前 りの 鰓
肢上の多数が 円筒器官」へ と変形 しいることであ るの一連 の上 肢付属器官の特
な 体 制 は,カ イ エ ビ 科 と して は 全 く未 知 の で り,か つ 異 例 の 形 質 で も あ る た め,
カ イ エ ビ 科 の 標 徴 を 再 評 価 し,同 に お い て 新 た に 定 義 さ れ た2亜 科(バ カル カ イ エ
科Baikalolkhoniinaeお び カ イ エ ビ亜 科Cyzicinae)を 提 示 。 本 種 以 外 の カ イエ
目 と し て,今 日 ま に 東 ア ジ ア(極 ロ シ ア,モ ゴル,中 国,韓 国 お よ び 日本)の 隣 接
地 域 ら は,4科(マ カ イ エ 科Cyclestheriidae,カ イ エ ビ 科Cyzicidae,ト カ イ エ
科Leptestheriidaeお よ び ヒ メ カ イ エ ビ 科Limnadiidae)に さ れ る7属11種 が 知 られ
て い る 。こ れ ら の 分 布 は,4つ の 動 物 地 理 学 的 な 要 素 よ っ て ほ ぼ 説 明 さ れ,種 多 様 性
つ い て は,ヨ ー ロ ッ パ の カ イ エ ビ相 な,緯 う 明確 な 勾 配 が 認 め れ た 。 東
ア の カ イ エ ビ類 に つ い て,種 ベ ル ・タ ク サ リス ト と検 索 表 し た。
... Naganawa (2001b) treated Eocyzicus as a junior synonym of Cyzicus, however this is not supported by molecular studies (Schwenter et al. 2009;Schwentner et al. 2020a). Naganawa (1999) created Baikalolkhoniinae to accommodate a new species of cyzicid clam shrimp from Russia. Brtek (2002) elevated that taxon to family status with no explanation or justification. ...
... Baikalolkhonia tatianae is the type species of the genus. Naganawa (1999Naganawa ( 2001b placed this genus initially in the Cyzicidae in its own subfamily, due to supposed shared characters between Cyzicidae and Leptestheriidae. Brtek (2002) raised the subfamily to family rank with no explanation or justification. ...
... The fact that two species in this genus are both endemic to Olkhon Island (some 720 km 2 ) (Galazy and Naganawa 2010), and the fact that Naganawa (1999) states that the type series of B. tatianae is immature, strongly suggest that both Baikalolkhonia are the same species. ...
Article
The Spinicaudata (spiny clam shrimp) are a large group of freshwater, bivalved branchiopod crustaceans in need of taxonomic revision. Herein, the extant Spinicaudata families and genera are defined and diagnosed according to modern standards. An annotated catalogue of the Spinicaudata taxa is presented with synonyms. More than 747 spinicaudatan taxa are presented, of which 215 are considered valid families, genera and species. Chresonyms are provided for taxa redescribed according to modern standards. It is hoped that this catalogue will provide a basis for further taxonomic revision and phylogenetic work within the Spinicaudata.
... Although "conchostracan" branchiopods (the suborders Laevicaudata, Spinicaudata, and Cyclestherida, formerly treated as comprising the order Conchostraca; see Martin & Davis, 2001) are known from eastern Asia, records from Southeast Asia are rare. East Asian clam shrimp, reviewed recently by Naganawa (1999), include numerous records of six nominal species from Japan (also see Grygier et al., 2002), seven species from China (with many other Chinese nominal species purportedly being their junior synonyms) (Naganawa, 1999;Naganawa & Orgiljanova, 2000), three species from Korea (Yoon & Kim, 1992, two species from the Baikal region of southern Siberia (Naganawa, 1999), and six from Mongolia (Brtek et al., 1984;Naganawa et al., 2001, Naganawa & Zagas, 2002. In contrast, records from Southeast Asia include only the species Cyclestheria hislopi (Baird, 1859), although one of us (MJG, unpublished data) has examined a sample of Eulimnadia sp. from northeastern Thailand. ...
... Although "conchostracan" branchiopods (the suborders Laevicaudata, Spinicaudata, and Cyclestherida, formerly treated as comprising the order Conchostraca; see Martin & Davis, 2001) are known from eastern Asia, records from Southeast Asia are rare. East Asian clam shrimp, reviewed recently by Naganawa (1999), include numerous records of six nominal species from Japan (also see Grygier et al., 2002), seven species from China (with many other Chinese nominal species purportedly being their junior synonyms) (Naganawa, 1999;Naganawa & Orgiljanova, 2000), three species from Korea (Yoon & Kim, 1992, two species from the Baikal region of southern Siberia (Naganawa, 1999), and six from Mongolia (Brtek et al., 1984;Naganawa et al., 2001, Naganawa & Zagas, 2002. In contrast, records from Southeast Asia include only the species Cyclestheria hislopi (Baird, 1859), although one of us (MJG, unpublished data) has examined a sample of Eulimnadia sp. from northeastern Thailand. ...
... Although "conchostracan" branchiopods (the suborders Laevicaudata, Spinicaudata, and Cyclestherida, formerly treated as comprising the order Conchostraca; see Martin & Davis, 2001) are known from eastern Asia, records from Southeast Asia are rare. East Asian clam shrimp, reviewed recently by Naganawa (1999), include numerous records of six nominal species from Japan (also see Grygier et al., 2002), seven species from China (with many other Chinese nominal species purportedly being their junior synonyms) (Naganawa, 1999;Naganawa & Orgiljanova, 2000), three species from Korea (Yoon & Kim, 1992, two species from the Baikal region of southern Siberia (Naganawa, 1999), and six from Mongolia (Brtek et al., 1984;Naganawa et al., 2001, Naganawa & Zagas, 2002. In contrast, records from Southeast Asia include only the species Cyclestheria hislopi (Baird, 1859), although one of us (MJG, unpublished data) has examined a sample of Eulimnadia sp. from northeastern Thailand. ...
Article
New records of the clam shrimp Cyclestheria hislopi are reported for Southeast Asia, including the first records from Malaysia, where the species was found in tin mine takes, and records from Java and Cambodia.
... For example, the situation of clam shrimps (order Spinicaudata) on Olkhon Island appears complicated. Two populations from lakes on the northwestern coast were closely related to the group in the Mongolian Gobi steppe region; whereas those from other lakes distant from the coast of Olkhon Island show general appearances highly endemic to the island (Naganawa 1999;Brtek 2002;Galazy and Naganawa 2010). It is unlikely that the latter populations came into secondary contact after the breakdown of the previously existing extrinsic populations. ...
... This suggests that to an extent, the deep water of Lake Baikal serves, as an effective barrier to genetic mixing between the two groups of Olkhon Island and the group inhabiting 'mainland' water bodies, thereby contributing to allopatric speciation. For these essentially lentic, shallow-water clam shrimps (Baikalolkhonia tatianae Naganawa, 1999 and Baikalolkhonia shmakini Naganawa in Galazy and Naganawa, 2010), the rapid current, strong waves, or both must be an insurmountable obstacle to the migration of individuals from Olkhon Island across even a small strait of Lake Baikal to the mainland. In the contact zone, nevertheless, some special mechanism such as hybrid breakdown may be operating; however, this needs to be substantiated in future studies. ...
Article
Order Anostraca (fairy shrimp of large branchiopods) is a primitive crustacean group, retaining ancient forms and ecology. The Holarctic family Chirocephalidae originated over 100 million years ago; it is a very long-lived freshwater taxon that has survived from the Mesozoic to the present. Thus, using this taxon as an indicator, we verified how the geographical distribution of freshwaters shifted during the ancient era. We used newly collected samples of Drepanosurus uchidai from Aomori (northern Japan) and Galaziella baikalensis and Branchinecta orientalis from Olkhon Island (the largest lake-bound island of Lake Baikal, Russia) to sequence 658 bp of COI gene. These sequences, plus those of 16S rRNA gene (~ 550-bp mt16S rDNA fragment), were compared with those retrieved from GenBank. To re-evaluate and clarify phylogenetic relationships among the Chirocephalidae that remains confused till now, six genera of the family, including Polyartemiella, Drepanosurus, Eubranchipus, Chirocephalus, Artemiopsis, and Galaziella species were used for molecular analyses. Small water bodies usually have comparatively short lives and fade away sooner or later due to growth of aquatic plants and accumulation of bottom sediments. In such environments, refugia formed on the shores of large-scale lakes were necessary for large branchiopods to survive several Ice Ages. The lake shorelines have moved with the growth or decline of the lakes, but the habitats of large branchiopods sporadically left behind can now be confirmed as a history of the shifting geographical distribution of global freshwaters. For example, two types of large branchiopod populations from island-bound water bodies on Olkhon Island are recognized: (1) populations on the northwestern coast that are closely related to the group in the Mongolian Gobi steppe region, and (2) populations in other areas distant from the coast that are highly endemic to the island. Based on fossil records and genetic distances, an absolute differentiation time of world chirocephalids can be estimated as 140 million years ago in the Mesozoic era. On the other hand, the age of Lake Baikal is only 25‒30 million years at the most. Therefore, extant large branchiopods of Olkhon Island must have first appeared near the present lake catchment after separation from their ancestral populations that had originated in Europe, and before the formation of Lake Baikal.
... It is now known that they shared a gross morphology very similar to that of other fossil and extant Spinicaudata. The evolution of radial carinae is not restricted to the leaioids and is seen in members of the afrograptids, suggested to be of similar ontogenetic origin as some umbonal 'nodes' seen in some palaeolimnadiid specimens and, interestingly, has been reported in the extant Siberian cyziciid Baikalolkhonia tatianae (Naganawa, 1999;Galazy and Naganawa, 2010). However, Schram (2014: 1346) could not decide whether Leaiina sits as a sister group to Laevicaudata (Lynceus), or is a distinct clade within Onychocaudata, or sits within Spinicaudata. ...
Article
In order to understand relationships between living and fossil groups of spinicaudatan clam shrimp, it is important to review historical and contemporary attempts at evaluating the evolutionary history of the group. A comprehensive review of previous phylogenetic and paleontological work is presented here and considered in an evolutionary context in an attempt to bridge the gap between neontological and fossil works and to present a foundation upon which future studies may contribute to the understanding of spinicaudatan evolutionary history. This study is broken into three discrete sections dealing with various aspects of spinicaudatan neontology and paleontology. First, a brief review of the current state of branchiopod systematics is presented. Second, we offer reviews of contemporary efforts in the paleontological study of fossil Spinicaudata with familial and super-familial descriptions of major fossil groups. Finally, an effort to establish biologically sound hypotheses of relatedness between fossil and living lineages of ‘clam shrimp’ is presented. We conclude that attempts to integrate modern and extinct representatives of the spinicaudatans in a holistic approach result in many of the fossil families becoming paraphyletic or polyphyletic, highlighting the persistent rift between biological and palaeontological studies of the group. It is our hope that the hypotheses presented here will aid in a more synthetic studies of Spinicaudata and also allow biological patterns to be investigated across the groups over geologic time.
... The suborder spinicaudata reported from East Asia reviewed by Naganawa (1999). Records from South East Asia included only circumtropical species. ...
Article
Full-text available
Conchostracans are commonly known as “Clam Shrimps” because their superficial resemblance with that of bivalved molluscs. There are five families established under this group and their ineterrelationships to each other are unclear until today. All of them possess a bivalved carapace with two valves joined by a strong adductor muscle. Reduced abdomen and their ability to be completely enclosed within a bivalved carapace is the key and unique character which isolate this group from other anostracans and notostracans. DOI: http://dx.doi.org/10.3126/on.v10i1.7797
... As in other groups, the eggs can withstand dessication and persist in the environment for years awaiting the water necessary for them to hatch. REGIONAL TAXA The suborder Spinicaudata in East Asia, reviewed recently by Naganawa (1999) and Naganawa and Orgiljanova (2000b), includes numerous records from Japan, Korea, and Russia (Naganawa 1999). Records of clam shrimp from Mongolia include Eocyzicus davidi and the laevicaudatan Lynceus dauricus (Brtek et al. 1984). ...
... Brtek (1997) accepted only two valid genera, Cyzicus and Eocyzicus with most Caenestheria synonymised into Eocyzicus and most Caenestheriella into Cyzicus, but with some synonymised into the opposite genus. Naganawa (1999) maintained this approach, as have Dumont and Negrea (2002) in their review of Branchiopoda. ...
Article
Eocyzicus is defined as those cyzicid spinicaudatans with a round condylus dorso-posteriorly on the head, a wide space between the head and trunk, and the male rostrum spatulate. Furthermore, most if not all species have a dorsal columnar lobe on the posterior-most trunk segments terminating in a single spine. Eocyzicus parooensis Richter and Timms is widespread in Australian inland hyposaline waters, and Eocyzicus argillaquus n. sp. also occurs across the inland but generally in turbid freshwater clay pans. The two species differ morphologically in number of trunk segments, head structure, features of the caudal furcae, and in a number of minor features.
... Straškraba 1965) and because some authors synonymise species without argument (e.g. Brtek 1997; Naganawa 1999) and still others do not accept some genera (e.g. Brtek 1997; Dumont and Negrea 2002). ...
Article
Full-text available
Eoleptestheria ticinensis, a highly variable Eurasian species, was collected from three widely separated sites in northern Australia. Each population is described and compared with the eight described species of Eoleptestheria, now all synonyms of E. ticinensis. It is postulated that the Australian occurrences of these clam shrimps are initiated or maintained by dispersal due to migrating birds from China.
Article
The large branchiopod crustacean fauna (fairy shrimp, tadpole shrimp and clam shrimp) of the Neotropical Bioregion are incompletely known, with scattered records for many taxa, and many new taxa discovered and described regularly. As an aid to furthering our knowledge of the group in this region, we present an assortment of notes and records on various Neotropical taxa. We present our information in the form of a checklist, listing all reported species, with a review of their known distribution, with 56 new distributional records for 29 taxa. We also include a revised description of Spiralifrons mira based on new material from Brazil, and provide important comments on the Leptestheriidae, reducing Strakrabiidae, Straskrabia, and Brtekia to synonymy. The information presented here will assist in additional studies, surveys, and conservation, as well as help develop a biogeographical understanding of this vast region. Thus, we have compiled these records so that it will be available to other researchers. Future survey efforts will undoubtedly reveal additional records and taxa.