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ZOOTAXA
ISSN 1175-5326 (print edition)
ISSN 1175-5334 (online edition)
Accepted by B. Frable: 30 Apr. 2020; published: 22 Jun. 2020 41
Zootaxa 4802 (1): 041–060
https://www.mapress.com/j/zt/
Copyright © 2020 Magnolia Press Article
https://doi.org/10.11646/zootaxa.4802.1.3
http://zoobank.org/urn:lsid:zoobank.org:pub:7FE0057D-06F4-4B02-A4FB-CC0F89FAF5D5
Systematic reappraisal of the anti-equatorial fish genus Microcanthus Swainson
(Teleostei: Microcanthidae), with redescription and resurrection of Microcanthus
joyceae Whitley
YI-KAI TEA1,3* & ANTHONY C. GILL1,2,3
1School of Life and Environmental Sciences, University of Sydney, Sydney, Australia.
2Chau Chak Wing Museum, Macleay Collections, The University of Sydney, New South Wales 2006, Australia.
�
anthony.c.gill@sydney.edu.au https://orcid.org/0000-0002-8990-3657
3Department of Ichthyology, Australian Museum Research Institute, Australian Museum, 1 William Street, Sydney, New South Wales
2010, Australia.
*Corresponding author.
�
yi-kai.tea@sydney.edu.au; https://orcid.org/0000-0002-2146-2592
Abstract
The taxonomy and classification of the microcanthid fish genus Microcanthus Swainson has been a subject of contention
dating back to the 19th century. Its allopatric, disjunct anti-equatorial distribution across the Indo-West Pacific has resulted
in the recognition of several nominal taxa, though these have been widely regarded as synonyms of Microcanthus strigatus
(Cuvier). Following the results published in a companion study elsewhere by the authors, the taxonomy of Microcanthus
and the validity of these nominal synonyms are herewith revised. Microcanthus strigatus is redescribed on the basis of
66 specimens from East Asia, Hawaii and Western Australia, and M. joyceae is resurrected and redescribed on the basis
of 25 specimens from eastern Australia and the southwest Pacific. Microcanthus differs from other microcanthid genera
in having the following combination of characters: dorsal-fin rays XI,15–17 (usually XI,16); anal-fin rays III,13–15
(usually III,14); pectoral-fin rays 15–17 (usually 16); scales ctenoid with ctenial bases present; lateral-line scales partially
or heavily obscured by adjacent scales; and body pale in preservation with five horizontal dark stripes reaching the
posterior edges of dorsal and anal fins, and base of caudal fin. The review is accompanied by a key to the genera of
Microcanthidae.
Key words: taxonomy, ichthyology, cryptic species, anti-tropical, stripey
Introduction
The microcanthid fish genus Microcanthus Swainson (Stripey) has a rich, albeit confusing history dating back to
the 19th century. The type species of the genus (as Chaetodon strigatus) was first described by Cuvier in 1831, in
his 22-volume treatment of ichthyology titled Histoire naturelle des poissons (Cuvier & Valenciennes 1831). The
publication served as a compendium of the fishes of the world, with systematic treatments of over 4000 species.
Nearly half of these species were new to science at the time. Cuvier (in Cuvier & Valenciennes 1831) described
Chaetodon strigatus in the seventh volume of his Histoire naturelle des poissons based on an unpublished manu-
script description by Georg H.F. von Langsdorff of specimens collected in Nagasaki, Japan. Although sufficient at
the time, the description was brief. Cuvier placed Chaetodon in the family Squammipennes, which included fishes
with a compressed body form and scaly dorsal and anal fins. Within this genus, Cuvier included species with the
following combination of characters: long bristle-like teeth, a single un-notched dorsal fin, a short snout, and no
spines on the preopercle. Shortly after, Swainson (1839) revised the classification of fishes, erecting Microcanthus
as a subgenus of Chaetodon in the family Chaetodonidae [sic].
Several decades later, a similar fish, Neochaetodon vittatus Castelnau, was described from Western Australia by
Castelnau (1873). He erected the genus Neochaetodon for his new species and C. strigatus. As ichthyological explo-
ration proceeded across the Pacific, so did reports of Microcanthus from previously undocumented regions. Several
new species were described outside Japan and Western Australia: Microcanthus howensis Whitley (1931) from Lord
Howe Island, M. joyceae Whitley (1931) from New South Wales, and M. hawaiiensis Fowler (1941) from Hawaii.
TEA & GILL
42 · Zootaxa 4802 (1) © 2020 Magnolia Press
.
Since Swainson’s Microcanthus (1839) takes precedence over Castelnau’s Neochaetodon (1873), Microcanthus
currently stands as a valid genus. However, the nominal species proposed by Castelnau, Fowler, and Whitley were
widely regarded as synonyms of M. strigatus (Hoese & Bray 2006; Randall 2007; Knudsen & Clements 2016;
Fricke et al. 2019). An exception is Kuiter (1993), who initially suggested that the Western Australian and eastern
Australian populations may represent different species (M. vittatus and M. howensis, respectively), and later (Kuiter
& Kuiter 2018) recognised M. strigatus (East Asia), M. vittatus (Western Australia), and M. joyceae (eastern Aus-
tralia and Lord Howe Island) as valid.
We here include Microcanthus in the Microcanthidae, along with Atypichthys Günther (1862), Neatypus Waite
(1905) and Tilodon Thominot (1881). The classification of all four genera has been considerably confused (Table
1). For much of its history, Microcanthus has been classified in the family Chaetodontidae, an extension of Cuvier’s
(1831) original placement of the type species in the genus Chaetodon and Swainson’s (1839) original familial as-
signment of Microcanthus to the Chaetodonidae [sic]. In contrast, Bleeker (1876) erected the Microcanthini for
Microcanthus and Atypichthys, one of two tribes he included in his family Scorpidiformes (= Scorpididae). Fra-
ser-Brunner (1945) also argued against a chaetodontid relationship for Microcanthus and classified it also in the
Scorpididae, along with Atypichthys and Neatypus. Johnson (1984) refined the Scorpididae on the basis of potential
synapomorphies (not surveyed in all included taxa), classified Microcanthus, Atypichthys and Neatypus in the Mi-
crocanthidae, and noted that microcanthid larvae are more similar to kyphosid and terapontid larvae than to scorpi-
dids. He overlooked Tilodon, which had been usually assigned to either the Scorpipidae, or, as its junior synonym,
Vinculum McCulloch (1914), in Chaetodontidae.
In addressing the phylogenetic position of the girellid Graus nigra Philippi (previously placed in the family
Labridae), Johnson & Fritzsche (1989) briefly compared fish taxa with Freihoffer’s (1963) pattern 10 of the ramus
lateralis accessorius (RLA) facial nerve. These were Girellidae, Kyphosidae, Scorpididae, Microcanthidae, Arripi-
dae, Oplegnathidae, Kuhliidae, Terapontidae, Stromateoidei and Nematistius Gill. Johnson & Fritzche suggested the
RLA 10 pattern was a potential synapomorphy of these taxa, although they rejected a relationship with Nematistius
in view of evidence that supported its relationship to carangoid fishes. Leis & van der Lingen (1997) noted that the
southern African Dichistiidae also possessed an RLA 10 pattern, noting general similarities in larval morphology
with other RLA 10 families. Neira et al. (1997) compared larvae of certain RLA 10 families (Arripidae, Girellidae,
Kyphosidae, Microcanthidae and Scorpididae) but were unable to provide evidence for either the monophyly of the
grouping or for relationships within the group.
The recognition of Johnson’s Microcanthidae (with or without Tilodon) has not been unanimous amongst ich-
thyologists. In particular, Nelson (1994) opted to treat Microcanthus as a member of the family Kyphosidae, com-
prising the subfamilies Girellinae, Kyphosinae, Microcanthinae, Parascorpidinae, and Scorpidinae. Other authors
recommended elevating each of these subfamilies to familial status: Girellidae, Kyphosidae, Microcanthidae, Para-
scorpididae, and Scorpididae (Francis 2001; Randall 2005; Allen & Erdmann 2012). Because various molecular
studies have not recovered a monophyletic Kyphosidae that includes the above taxa (see e.g., Yagishita et al. 2002;
Knudsen & Clements 2016), we here elect to recognise the Microcanthidae as a full family, distinct from Kyphosi-
dae. However, no synapomorphies have yet been proposed for the family, and no molecular studies have included all
four genera. We therefore consider the composition of the family to be tentative. The distribution of the four genera
in Australia corresponds well with Australian marine biogeographic areas (Gill & Mooi 2017): Tilodon is confined
to the Flindersian area; Neatypus is confined to the western Flindersian area; Atypichthys occurs in the Peronian
and eastern Flindersian, extending eastwards to northern New Zealand and the Kermadec Islands; Microcanthus
has a disjunct Australian distribution, with a Leeuwin distribution in the west and a Peronian/eastern Flindersian
distribution in the east, the latter extending eastwards to New Caledonia and Norfolk Island. Microcanthus is the
only microcanthid genus to have a distribution outside of the southern Australian region, with an anti-equatorial
distribution that includes East Asia and the Hawaiian Islands.
In a recent study, Tea et al. (2019) investigated the population genomics and historical biogeography of M. striga-
tus. Although they found deep mitochondrial divergences across all geographical populations, their analysis of two sets
of 7,120 and 12,771 genome-wide single-nucleotide polymorphisms suggested instead the presence of two genetically
distinct populations. One of these populations exhibited more nuanced genetic sub-structuring but with evidence of
intermittent, historical gene flow. These findings were supported by an analysis of 36 morphological characters, em-
phasizing the importance of using a combined integrative data set for the evaluation of widespread species, as well as
the potential international implications that that has for conservation and biodiversity management of cryptic species.
REVISION OF THE GENUS MICROCANTHUS Zootaxa 4802 (1) © 2020 Magnolia Press · 43
TABLE 1. Selected classifications showing assignment of microcanthid genera to families through time.
Author Chaetodontidae Scorpididae Kyphosidae Microcanthidae
Swainson, 1839 Microcanthus
Bleeker, 1876 Atypichthys, Microcanthus
(as Scorpidiformes)
Tribe (Microcanthini) of
Scorpidiformes (= Scorpididae)
Waite, 1905 Microcanthus Atypichthys, Neatypus
Regan, 1913 Atypichthys, Neatypus
McCulloch, 1922 Microcanthus, Vinculum2Atypichthys
Jordan, 1923 Microcanthus, Therapaina1,
Neochaetodon1, Vinculum2
Atypichthys, Tilodon, Neatypus
Ahl, 1923 Microcanthus, Vinculum2,
Chaetodon (Paracoradion)2
Fowler & Bean, 1929 Microcanthus, Vinculum2Atypichthys, Neatypus, Tilodon (as
Scorpidae)
McCulloch, 1929 Microcanthus, Vinculum2Atypichthys, Neatypus Tilodon
Fraser-Brunner, 1945 Atypichthys, Microcanthus, Neaty-
pus
Golvan, 1962 Microcanthus, Vinculum2Atypichthys, Neatypus, Tilodon
Norman, 1966 Microcanthus, Vinculum2Atypichthys, Neatypus, ?Tilodon
Nelson, 1976 Microcanthus Subfamily of Kyphosidae (as
Scorpinae [sic])
Atypichthys (in Scorpinae [sic])
......continued on the next page
TEA & GILL
44 · Zootaxa 4802 (1) © 2020 Magnolia Press
TABLE 1. (Continued)
Author Chaetodontidae Scorpididae Kyphosidae Microcanthidae
Nelson, 1984 Subfamily of Kyphosidae Atypichthys, Neatypus, Microcanthus, Vinculum2
(all in Scorpidinae)
Johnson, 1984 Atypichthys, Neatypus,
Microcanthus
Gosline, 1985 Microcanthus
Grant, 1987 Subfamily of Kyphosidae Neatypus, Atypichthys, Vinculum2, Microcanthus
(all in Scorpidinae)
Eschmeyer, 1990 Subfamily of Kyphosidae Atypichthys, Microcanthus, Neatypus, Vinculum2
(all in Microcanthinae), Tilodon (in Scorpidinae)
Subfamily of Kyphosidae
Nelson, 1994 Atypichthys, Neatypus, Microcanthus, Tilodon,
?Vinculum2 (all in Microcanthinae)
Subfamily of Kyphosidae
Gomon et al., 1994 Atypichthys, Neatypus, Tilodon
Kuiter, 1996 Atypichthys, Neatypus,
Microcanthus, Tilodon
Nelson, 2006 Atypichthys, Neatypus, Microcanthus, Tilodon,
?Vinculum2 (all in Microcanthinae)
Subfamily of Kyphosidae
Gomon, 2008 Atypichthys, Neatypus,
Microcanthus, Tilodon
1synonyms of Microcanthus
2synonyms of Tilodon.
REVISION OF THE GENUS MICROCANTHUS Zootaxa 4802 (1) © 2020 Magnolia Press · 45
The purpose of this paper is to address the taxonomic ramifications of the companion study by Tea et al. (2019).
We herewith revise the genus Microcanthus, redescribe Microcanthus strigatus on the basis of 66 specimens, res-
urrect M. joyceae from synonymy, and redescribe the latter on the basis of 25 specimens (including the holotype)
from eastern Australia and the south-west Pacific. Additionally, a key to the genera of Microcanthidae is provided
below.
Materials and methods
Methods and results for molecular dating, population genomics, and molecular phylogenetics are described by Tea
et al. (2019). Owing to the scope of the present study, we have chosen not to describe the molecular data in detail
again here. Instead, we refer to the key results where relevant.
Measurements were recorded to the nearest 0.1 mm using digital callipers. Lengths of specimens are presented
in mm standard length (SL), which was measured from the tip of the snout to the middle of the caudal peduncle
at the vertical through the posterior edge of the hypural plate. Morphometric measurements were made follow-
ing triangulation of landmark characters as described by Gill (2004). All other measurements not included in the
triangulation are comprised of fin and head structures. Counts include numbers of fin rays, spines, rows of scales
in lateral series, and vertebral counts. For the principal components analysis presented in Tea et al. (2019), a total
of 26 morphometric characters, eight meristic characters, and two coloration characters were examined from 87
specimens of Microcanthus from throughout its geographical range. Here we include data from an additional two
specimens from Hawaii that were too damaged to contribute meaningful data towards the PCA in Tea et al. (2019)
and four cleared and stained specimens from eastern Australia.
Osteological details were determined from x-radiographs taken at the Australian Museum, Sydney and from
four specimens from eastern Australia that were cleared and stained for cartilage and bone (Taylor & van Dyke
1985). Terminology of intermuscular bones and ribs follows Patterson & Johnson (1995) and Johnson & Patterson
(2001). “Predorsal” formulae (configuration of supraneurals, anterior dorsal pterygiophores, and neural spines) fol-
low Ahlstrom et al. (1976). Terminology of scales follows Roberts (1993).
Counts of principal caudal-fin rays follow Gill (2004): the uppermost principal caudal-fin ray is the ray articu-
lating with hypural 5, and the lowermost principal caudal-fin ray is the ray articulating between the distal tips of the
parhypural and the haemal spine of preural centrum 2. Principal and branched caudal-fin rays are presented as upper
+ lower. Upper principal caudal rays are those associated with hypurals 3–5, and lower rays are those associated
with hypurals 1–2 and the parhypural. Procurrent caudal-fin rays are those dorsal and ventral (or anterior) to the
principal rays. Total caudal-fin rays include the dorsal procurrent rays, principal caudal rays, and ventral procurrent
rays. Gill-raker counts were of the total number of outer rakers on the first arch, including rudiments.
In the description that follows, modal counts of the data are presented for all specimens examined. These are
followed, where variation was noted, by data in parentheses (except in generic descriptions, where only range of
variation is given). Frequency distributions for counts of diagonal rows of scales in lateral series, circumpeduncular
scales, and dorsal-, anal- and pectoral-fin rays are presented in Table 2. Specimens examined in this study were
borrowed on loan from the following institutions (museum codes follow Sabaj 2019): AMS—Australian Museum,
Sydney; ANSP—The Academy of Natural Sciences, Philadelphia; BPBM—The Bernice Pauahi Bishop Museum,
Honolulu; KAUM—Kagoshima University Museum, Korimoto; KPM—Kanagawa Prefectural Museum of Natu-
ral History, Odawara; USNM—National Museum of Natural History, Smithsonian Institution, Washington D.C.;
WAM—Western Australian Museum, Perth.
Microcanthus Swainson
Microcanthus Swainson 1839: 170, 215 (as a subgenus of Chaetodon Linnaeus; type species Chaetodon strigatus Cuvier 1831,
by monotypy).
Therapaina Kaup 1860: 140 (type species Chaetodon strigatus Cuvier 1831, by monotypy).
?Helotosoma Kaup 1863: 162 (type species Helotosoma servus Kaup 1863, by monotypy).
Neochaetodon Castelnau 1873: 130 (type species Neochaetodon vittatus Castelnau 1873, by subsequent designation of Jordan
1919: 368).
TEA & GILL
46 · Zootaxa 4802 (1) © 2020 Magnolia Press
Diagnosis. Microcanthus is readily distinguished from all other microcanthid genera in having the following com-
bination of characters: dorsal fin with XI spines and 15–17 (usually 16) segmented rays; anal fin with III spines
and 13–15 (usually 14) segmented rays; pectoral fin with 15–17 (usually 16) rays; scales ctenoid, with ctenial bases
present; lateral line scales partially or heavily obscured by adjacent scales; and body pale in preservation with five
horizontal dark stripes reaching the posterior edges of dorsal and anal fins, and base of caudal fin.
Description. Dorsal-fin rays XI,15–17, all segmented rays branched except anteriormost; soft dorsal fin ex-
tensively covered in scales, scales reaching almost to distal edge of fin; anal-fin rays III,13–15, all segmented rays
branched; basal portion of dorsal and anal fins with scale sheaths; pectoral-fin rays 14–17, all rays branched except
for uppermost; dorsal and anal fin spines stiff and pungent; second anal-fin spine blade-like; base of pectoral fin
covered in numerous small scales, scales reaching just beyond base of fin rays; inner pelvic-fin ray not attached to
body by membrane; pelvic-fin rays I,5, all segmented rays branched; upper procurrent caudal-fin rays 8–9; lower
procurrent caudal-fin rays 7–9; principal caudal-fin rays 9 + 8 (8 + 7 branched); total caudal-fin rays 32–35; lateral
line complete; tubed scales irregularly obscured by overlapping scales; scales ctenoid with ctenial bases; diagonal
rows of scales in lateral series 48–59; circumpeduncular scales 26–30; gill rakers 16–18; branchiostegals 7.
Vertebrae 10 + 15; supraneurals 3; predorsal formula 0/0+0/2/1+1; trisegmental pterygiophores associated with
segmented rays of the dorsal (except the anteriormost 3–5 bisegmental) and anal fins (except the anteriormost 3–4
bisegmental); terminal rays in dorsal and anal fins with well-developed stays; ribs present on vertebrae 3 through
10; epineurals present on vertebrae 1 through 10–12 (usually 11); parhypural and hypurals 1–5 autogenous; well-
developed hypurapophysis on parhypural; epurals 3, anteriormost largest; two uroneurals; uppermost procurrent ray
on ventral part of caudal fin with procurrent spur, the ray immediately below foreshortened (Johnson 1975); haemal
spines on preural centrum 2 and 3 autogenous (Figure 1); interarcual cartilage present between uncinate process of
epibranchial 1 and pharyngobranchial 2; no toothplates on epibranchial 2 or 3; well-developed suborbital shelf on
third infraorbital; posttemporal and preopercle finely serrate; laterosensory canal present in supracleithrum.
FIGURE 1. X-radiograph of Microcanthus strigatus, KPM-NI 24269, 73.8 mm SL, Yakushima Island, Japan. Radiograph by
A. Hay.
REVISION OF THE GENUS MICROCANTHUS Zootaxa 4802 (1) © 2020 Magnolia Press · 47
Body laterally compressed, moderately tall in lateral view, dorsal-fin origin to pelvic-fin origin 51.9– 59.8%
SL; head small 28.1–36.6% SL; snout acute, 7.8–11.0% SL; head profile steeply sloping, slightly concave; eye
large, 11.0–14.6% SL; mouth terminal, horizontal to slightly oblique; distal portion of maxilla partly covered by
lachrymal, barely reaching anterior edge of orbit; preopercle serrated; lower jaw projecting slightly; jaws with nu-
merous rows of small, setiform teeth anteriorly; preorbital region naked; scales large, ctenoid with ctenial bases,
covering the body from postorbital region of operculum and the cheek, posteriorly to base of caudal fin; interorbital
region naked, 8.3–11.4% SL in width; pelvic fin free, not bound to body by a membrane, situated well behind verti-
cal through pectoral-fin base; caudal fin emarginate.
Etymology. The generic epithet Microcanthus is a combination of the Greek “mikros” for small, and “akantha”
for thorn, alluding to the minute crenulations on the preopercle (Swainson 1839).
Remarks. The various genera of Microcanthidae are readily separated on the basis of dorsal- and anal-fin
counts, scale morphology, body shape, and general coloration. Tilodon and Neatypus can be separated from Atypi-
chthys and Microcanthus in having ten dorsal fin spines (versus 11 in Atypichthys and Microcanthus) and higher
dorsal-and anal-fin ray counts. The four genera can be separated further on the basis of colour patterns, in having
either vertical or oblique bars versus horizontal or near-horizontal stripes (Figure 2).
The lateral-line scales of at least Microcanthus, Atypichthys and Tilodon are heavily obscured by overlapping
adjacent scales (Figure 3). This appears to be an ontogenetic character, as juveniles have mostly unobscured lateral-
line scales, but these become increasingly obscured in larger specimens. This character is not found in Neatypus
(checked for and examined in syntype of N. obliquus Waite; AMS I.7034). Whether it is a synapomorphy supporting
a relationship between Microcanthus, Atypichthys and Tilodon requires more investigation. We tentatively consider
Helotosoma servus Kaup (1863), type species of Helotosoma Kaup (1863), as a synonym of Microcanthus strigatus.
See Remarks for M. strigatus for discussion.
FIGURE 2. Genera of Microcanthidae. Tilodon and Neatypus are monotypic. A) Tilodon sexfasciatus, in situ photograph from
Blairgowrie, Victoria, Australia; B) Neatypus obliquus, in situ photograph from Bunbury, Western Australia; C) Microcanthus
joyceae, in situ photograph from Magic Point, Maroubra, New South Wales, Australia; and D) Atypichthys strigatus, in situ
photograph from Henry Head, Botany Bay, New South Wales, Australia. Photographs by S. Schulz (A), C. Mark (B), and E.
Schlogl (C & D).
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48 · Zootaxa 4802 (1) © 2020 Magnolia Press
FIGURE 3. Lateral-line scales of: A) Scorpis lineolatus (Scorpididae), AMS I.48993-001, 55.3 mm SL; B) Microcanthus joy-
ceae (Microcanthidae), AMS I.48994-001, 64.2 mm SL; C) Atypichthys strigatus (Microcanthidae), AMS I.48992-001, 93.9
mm SL. Drawings on right show portion of lateral line and adjacent scales. Lateral-line scales are show in dark grey; scale bars
indicate 2 mm. Photographs by Y.K. Tea; drawings by A.C. Gill.
Key to the genera of Microcanthidae
1 Dorsal-fin rays X, 20–21; anal-fin rays III,17–19; body with vertical or oblique bars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
- Dorsal-fin rays XI,15–18; anal-fin rays III,13–16; body with horizontal or near-horizontal stripes . . . . . . . . . . . . . . . . . . . . . . 3
2 Body circular in lateral view; dorsal- and anal-fin rays subequal in length; scales ctenoid; body pale in preservation (white to
cream in life) with five dark vertical bars (black in life); profile of head concave; caudal peduncle ringed with a dark vertical
bar (black in life); caudal fin slightly forked ...........................................................Tilodon
- Body ovate in lateral view; anterior dorsal- and anal-fin rays longer, outline of fish rhomboidal when fins extended; scales
cycloid; body pale in preservation (white to silver in life) with five tan oblique bars (brown to yellowish in life); profile of head
slightly rounded to almost straight; caudal peduncle not ringed with dark bar; caudal fin forked . . . . . . . . . . . . . . . . .Neatypus
3 Anal-fin rays III,15–16; body ovate in lateral view; anal-fin spines pungent, the second not blade-like; body pale in preservation
(silver in life) with 5–6 tan horizontal stripes (brown in life); profile of head gently sloping; caudal fin strongly forked . . . . . .
...........................................................................................Atypichthys
- Anal-fin rays III,13–15; body circular in lateral view; anal-fin spines pungent and bony, the second blade-like; body pale in
preservation (cream to bright yellow in life) with five near-horizontal dark stripes (black in life); profile of head steep, slightly
concave; caudal fin emarginate ................................................................Microcanthus
REVISION OF THE GENUS MICROCANTHUS Zootaxa 4802 (1) © 2020 Magnolia Press · 49
Taxonomic decisions
The following taxonomic accounts are intended to address the validity of nominal species supported by data pre-
sented in the companion publication investigating the historical biogeography and population genomics of Micro-
canthus (Tea et al. 2019). In summary, the genus Microcanthus represents a complex of deeply divergent cryptic
species corresponding to their geographical distributions (Figure 4A & 4B). These differences are reflected by deep
divergences in several mitochondrial DNA markers, in particular 16S ribosomal RNA (16S), cytochrome c oxidase
I (COI), and control region. Distance matrices for all three mitochondrial markers for examined specimens in each
population group are available in the electronic supplementary material of Tea et al. (2019).
Analysis of genome-wide single-nucleotide polymorphisms (SNPs) however reveals a more nuanced scenario,
indicating the presence of historical gene flow despite the strong signals in mitochondrial divergences, particularly
between the East Asian, Western Australian, and Hawaiian populations (Figure 4C). A phylogenetic analysis of a
concatenated SNP data set yielded a paraphyletic group for the abovementioned populations (Tea et al. 2019). How-
ever, sampled populations from the southwest Pacific were consistently placed as a separate, monophyletic clade
in every analysis. Specimens from the southwest Pacific are also distinguished on the basis of coloration patterns,
in lacking a series of spots on the lower abdomen, as well as in having the fifth body stripe relatively straight with-
out an inflection onto the anal fin. In contrast, specimens from the East Asian, Western Australian, and Hawaiian
populations usually have a series of spots on the lower abdomen, and with the fifth body stripe inflected onto the
anal fin.
Accordingly, we herewith recommend retention of Microcanthus strigatus for populations occurring in East
Asia, Western Australia, and Hawaii, and resurrection of Microcanthus joyceae from synonymy with M. strigatus
for populations occurring in eastern Australia and the southwest Pacific Ocean.
FIGURE 4. Phylogenetic relationships and population structure for Microcanthus. A) Tree inferred using maximum likelihood
and Bayesian inference based on mitochondrial 16S, COI and control region. Numbers at nodes indicate posterior probabilities
inferred using Bayesian analysis in MrBayes and likelihood bootstrap support from a maximum-likelihood analysis in RAxML.
Atypichthys (not shown) was used as the outgroup. B) Geographic distribution of Microcanthus. Geographic distributions of
Microcanthus are colour coded as follow: Blue—East Asia (M. strigatus); Yellow—Hawaii (M. strigatus); Pink—Western Aus-
tralia (M. strigatus); Purple—Southwest Pacific (M. joyceae). C) Bayesian clustering plots for 82 individuals of Microcanthus
from populations of M. strigatus from East Asia, Hawaii and Western Australia, and M. joyceae from the southwest Pacific. The
most likely number of partitions was K = 3 (LnP = -184055). The second most likely number of partitions was K = 4 (LnP =
-187956). For discussion of phylogenetic relationships and population genetics of Microcanthus, see Tea et al. (2019).
TEA & GILL
50 · Zootaxa 4802 (1) © 2020 Magnolia Press
Microcanthus strigatus (Cuvier in Cuvier & Valenciennes 1831)
Stripey
Figures 1, 4–7; Table 2
Chaetodon strigatus Cuvier (ex Langsdorff) in Cuvier & Valenciennes 1831: 25, pl. 170 (type locality: Nagasaki, Japan, based
on manuscript of Langsdorff; holotype ZMB 8157, not examined).—Waite 1902: 189 (Pinjarrah, Western Australia; syn-
onymy of C. strigatus Cuvier with Neochaetodon vittatum Castelnau, but not references to eastern Australian specimens).
Chaetodon (Microcanthus) strigatus.—Swainson 1839: 215 (new subgeneric assignment).
Therapaina strigatus.—Kaup 1860: 140 (new generic assignment).
?Helotosoma servus Kaup 1863: 162 (type locality: Japan; type specimens not located).
Neochaetodon vittatum Castelnau 1873: 130 (type locality, Freemantle, Western Australia; holotype MNHN A-4567, not exam-
ined).—Macleay 1881: 390 (checklist).
Microcanthus vittatus.—Whitley 1931: 112, pl. 13, fig. 3 (Western Australia; resurrection from synonymy).—Whitley 1964: 46
(checklist).
Microcanthus hawaiiensis Fowler 1941: 254, figs 6–7 (type locality, Honolulu, Hawaiian Islands; holotype ANSP 69740).
Microcanthus strigatus.—Jordan & Evermann 1902: 357 (list, Formosa (=Taiwan)).—Jordan & Fowler 1902: 541 (Japan).—
Seale 1914: 73 (Hong Kong).—Alexander 1922: 482 (Houtman Abrolhos, Western Australia).—McCulloch 1929: 248
(synonymy with Neochaetodon vittatum Castelnau 1873; distribution in part).—Tinker 1944: 241 (Hawaii, distribution in
part; illustration).—Fraser-Brunner 1945: 463, fig. 1A (in part, Asian specimen only).—Gosline 1971: 282 (zoogeographic
relationships of inshore fishes).—Springer 1982: (checklist, in part, Hawaiian distribution only).—Edgar 2000: 462 (dis-
tribution in part; colour photo, Houtman Abrolhos, Western Australia).—Randall & Lim 2000: 623 (checklist).—Hutchins
2001: 264 (checklist in part, Western Australian distribution only).—Friedlander 2004: 154 (checklist of fishes collected
for aquarium fisheries).—Mundy 2005: 411 (checklist).—Hoese & Bray 2006: 1324 (checklist in part, Western Australian
distribution only).—Senou et al. 2006: 474 (checklist, Sagami Sea, Japan).—Motomura et al. 2010: 133–134, fig. 259
(checklist, Kagoshima, Japan).—Parin et al. 2014: 376 (checklist, Japan and the Kuril Islands).—Kim et al. 2015: 147,
fig. 1b–c (distribution records).—Kwun et al. 2017: 142 (checklist, Korea).—Nakae et al. 2018: 282 (checklist, Ryukyus
Islands, Japan)
Diagnosis. Microcanthus strigatus is diagnosed in having the following combination of coloration characters: fifth
body stripe inflected toward the anal fin origin at an angle of 120–150° (usually 130°); lower abdomen usually with
a broken stripe, as a series of 2–5 (usually 3) spots and short dashes (Figures 5–7).
Description. Dorsal-fin rays XI,16 (15–17); anal-fin rays III,14 (13–15); pectoral-fin rays 16/16 (15–17); upper
procurrent caudal-fin rays 9 (8–9); lower procurrent caudal-fin rays 8 (7–9); total caudal-fin rays 32–35; diagonal
rows of scales in lateral series 55 (48–57); circumpeduncular scales 28 (26–30); gill rakers 16–17; branchiostegals
7. Frequency distribution of numbers of dorsal-, anal- and pectoral-fin rays, and numbers of circumpeduncular
scales and diagonal rows of scales in lateral series are presented in Table 2.
Body laterally compressed, moderately tall and roughly circular in lateral view, dorsal-fin origin to pelvic-fin
origin 51.9–59.3% SL; head small 28.1–36.6% SL; snout acute, 8.3–11% SL; eye large, 11.0–14.6% SL; interorbital
region naked, 8.7–11.1% SL in width.
As percentage of SL (based on examination of 66 specimens, 56.9–157.3 mm SL): predorsal length 41.7–49.0;
prepelvic length 42.0–50.1; dorsal-fin origin to pelvic-fin origin 51.9–59.3; pelvic-fin origin to anal-fin origin 27.3–
35.4; dorsal-fin origin to anal-fin origin 60.8–72.9; spiny dorsal-fin base length 32.6–45.1; soft dorsal-fin base
length 22.0–30.4; anal-fin origin to dorsal fin terminus 36.0–43.5; anal-fin base length 24.2–30.4; mid-dorsal fin to
anal-fin origin 47.4–60.7; dorsal-fin terminus to dorsal end of caudal peduncle 7.1–13.7; anal-fin terminus to ventral
end of caudal peduncle 6.3–10.1; anal-fin terminus to dorsal end of caudal peduncle 15.4–20.5; dorsal-fin terminus
to ventral end of caudal peduncle 14.6–19.5; first anal-fin spine 7.0–11.5; second anal-fin spine 16.0–21.1; third
anal-fin spine 8.6–14.7; pectoral-fin length 20.3–27.1; pelvic-fin length 22.0–29.7; pelvic fin spine 13.5–16.8.
Etymology. The specific epithet strigatus is the Latin for strigate, in having transverse bands or streaks of
colour.
Distribution and habitat. Microcanthus strigatus is known from East Asia, Hawaii and Western Australia
(Figure 4). In East Asia, it occurs in southern Japan, Korea, the eastern coast of China, Taiwan and Hong Kong. Pho-
tographs in the Image Database of Fishes, Kanagawa Prefectural Museum of Natural History (KPM), indicate that
the species commonly occurs in the Izu Peninsula and Sagami Bay (KPM-NR 16956), Okinawa Islands (KPM-NR
32524), Suruga Bay (KPM-NR 15245), and the Kii Peninsula (KPM-NR 84644). Microcanthus strigatus frequently
inhabits rocky areas and ledges in coastal warm-temperate reefs, but can occasionally be seen in harbours, embank-
ments, and coastal ports. Adults frequently school in large groups (Figure 6). It ranges between 10 and 30 m depth,
REVISION OF THE GENUS MICROCANTHUS Zootaxa 4802 (1) © 2020 Magnolia Press · 51
but can occur as shallow as 0.3 m (KPM-NR 4998) to as deep as 300 m (KPM-NR 11529). In Western Australia it is
known from Cape Leeuwin to the Exmouth Gulf. It also occurs in Hawaii, where it has been reported from Honolulu
Harbor, Haleiwa, Mokuleja, Moiliili, Kaneohe Bay, Kahala, and Molokai. Recent surveys suggest that the species
now has a more restricted and localized distribution to within Lydgate State Park in Kauai.
FIGURE 5. Microcanthus strigatus, KAUM-I. 98924, 104.3 mm SL, Tanegashima Island, Osumi Islands, Kagoshima Prefec-
ture, Japan. Note the broken stripe (as a series of spots) on the lower abdomen (black arrow) and the inflected anal-fin stripe
(white arrow). Photograph by Y.K. Tea.
Remarks. We tentatively consider Helotosoma servus Kaup (1863), type species of Helotosoma Kaup (1963),
as a synonym of M. strigatus. The genus has been previously regarded as a synonym of Atypichthys (e.g., Fowler
& Bean 1929; Golvan 1962; Norman 1966; Eschmeyer 1990; Fricke et al. 2019). The earliest reference to such
synonymy we were able to locate is Jordan (1919), who simply stated: “said to be a synonymy of Atypichthys
Gthr.” (Jordan 1919: 327). He did not, however, provide a justification or cite literature that provided further details.
However, Atypichthys is restricted to southern Australia and the southwest Pacific, whereas the type locality for H.
servus is Japan. Kaup’s description agrees well with our specimens of M. strigatus. The only noteworthy exceptions
are slight differences in the orientation of the body stripes and his record of 16 anal-fin rays. However, although our
specimens had only 13–15, usually 14 anal-fin rays, Randall et al. (1998) recorded 14–16 anal-fin rays for Micro-
canthus. It is also possible that Kaup counted the final “split-to-the-base” ray as two rays.
The holotypes of Chaetodon strigatus (ZMB 8157) and Neochaetodon vittatum (MNHN A-4567) were not
examined in this review as both are dried and cannot provide comparable morphometrics. Our justification for
synonymy of these nominal species is based largely on their type localities. The holotype of the C. strigatus was
illustrated in black and white by Cuvier & Valenciennes (1831, pl. 170). It is unusual in showing a pair of stripes
extending from the lower half of the pectoral fin. The upper of these corresponds to fifth body stripe of other speci-
mens, and the lower presumably to the broken stripe (as a series of spots; see Figure 5). The lower part of the body
adjacent to the anal fin is dusky, but is slightly darker immediately above the second anal-fin spine. We interpret this
as the inflected part of the fifth body stripe. A colour photograph of the dried holotype of N. vittatum is provided
on MNHN’s website. It lacks the broken stripe on the breast but has the characteristic fifth body stripe inflected
TEA & GILL
52 · Zootaxa 4802 (1) © 2020 Magnolia Press
toward the anal fin. Bauchot (1963) gave Melbourne, Victoria, as the locality for this specimen. However, this is in
error, and presumably is a consequence of the confusing subtitle of the paper in which the species was described:
“Supplement to the fishes of Victoria”.
FIGURE 6. A school of Microcanthus strigatus, underwater photograh at Yakushima, Japan. Note the characteristic inflected
anal-fin stripe and series of spots on the lower abdomen. Photograph by S. Harazaki.
Material examined. EAST ASIA: Japan, Osumi Islands, Nakayama fishing port, KAUM-I. 68452 (96.2 mm
SL); Japan, Osumi Islands, Nishinoomote fishing port, KAUM-I. 58577 (108.3 mm SL); Japan, Matsu-shima Island,
KAUM-I. 110003 (128.0 mm SL); Japan, Sato, Koshiki Islands, KAUM- I. 77255 (142.4 mm SL); Japan, Amami
Islands, Oshima-gun, KAUM-I. 57595 (122.6 mm SL); Japan, Shibushi Bay, KAUM-I. 30813 (131.8 mm SL); Ja-
pan, Koshiki Islands, KAUM-I.77752 (147.6 mm SL); Japan, Kumage, Yudomari Port, KAUM-I. 20063 (85.2 mm
SL); Japan, Osumi Islands, Nokan, Hamatsuwaki port, KAUM-I. 60871 (94.4 mm SL); Japan, Taijiri fishing port,
KAUM-I. 106014 (145.8 mm SL); Japan, Nishinoomote, KAUM-I. 80285 (148.4 mm SL); Japan, Sakinoyama,
Kataura, KAUM-I. 97830 (133.0 mm SL); Japan, Sakinoyama, Kataura, KAUM- I. 97829 (126.7 mm SL); Japan,
Matsushima, KAUM-I. 110002 (135.6 mm SL); Japan, Koshiki Islands, Nishi fishing port, KAUM-I. 79657 (82.8
mm SL); Japan, Chiringa Island, KAUM-I. 22548 (137.3 mm SL); Japan, Koshiki Islands, Satonishi fishing port,
KAUM-I. 80597 (157.3 mm SL); Japan, Yakushima Island, Nagata, mouth of Nagata River, KAUM-I. 25201 (81.4
mm SL); Japan, Yakushima Islands, tide pool east of Yudomari port, KAUM-I. 20062 (77.7 mm SL); Japan, Osumi
Islands, Makigou fishing port, KAUM-I. 66281 (120.0 mm SL); Japan, Uchinoura Bay, KAUM-I. 66684 (126.9
mm SL); Japan, Osumi Islands, Nishinoomote fishing port, KAUM-I. 98924 (104.4 mm SL); Japan, Sakinoyama,
Kataura, KAUM-I. 97828 (118.3 mm SL); Japan, Osumi Islands, Hamatsuwaki port, KAUM-I. 69058 (111.4 mm
SL); Japan, Shibushi Bay, KAUM-I. 30816 (134.8 mm SL); Japan, Osumi Islands, Nakayama fishing port, KAUM-
I. 68451 (105.4 mm SL); Japan, Ibusuki, southwest of Kawajiri fishing port, KAUM-I. 20639 (90.1 mm SL); Japan,
Osumi Islands, Makigou fishing port, KAUM-I. 66280 (102.6 mm SL); Japan, Osumi Islands, Nishinoomote fish-
ing port, KAUM-I. 98924 (104.3 mm SL); Japan, east of Sakinoyama, Kataura, KAUM-I. 97828 (118.1 mm SL);
Japan, Yakushima Island, Kurio Port, KPM-NI 24269 (73.8 mm SL); Japan, Yakushima Island, Koseda, KPM-NI
22923 (80.6 mm SL); Japan, Ryukyu Islands, Wan port, KPM-NI 26381 (109.2 mm SL); Japan, Okinawa Pre-
fecture, Ryukyu Islands, Gushi fishing port, KPM-NI 22418 (136.0 mm SL); East China Sea, KAUM-I. 60193
(142.4 mm SL); Hong Kong, ANSP 76638 (106.0 mm SL); Hong Kong, ANSP 76867 (96.2 mm SL); China, Fujian
province, Pingtang, ANSP 76579 (80.5 mm SL); WESTERN AUSTRALIA: Rottnest Island, WAM P.4945-001 (2:
REVISION OF THE GENUS MICROCANTHUS Zootaxa 4802 (1) © 2020 Magnolia Press · 53
80.5–81.3 mm SL); Rottnest Island, WAM P.33193-001 (2: 79.3–81.5 mm SL); Rottnest Island, WAM P.5601-001
(2: 98.2–113.0 mm SL); Rottnest Island, WAM P.5632-001 (114.0 mm SL); Rottnest Island, WAM P.4946-001 (56.9
mm SL); Woodman Point, WAM P.25225-003 (2: 70.9–73.5 mm SL); Shark Bay, WAM P.5382-001 (2: 76.7–77.0
mm SL); Shark Bay, WAM P.5868-001 (79.7 mm SL); Shark Bay, WAM P.4436-001 (77.6 mm SL); HAWAII: Oahu,
Laie, ANSP, 86808 (84.1 mm SL); Oahu, Moiliili, BPBM 4202 (71.4 mm SL); Oahu, Kaneohe Bay, BPBM 9794 (2:
106.0–109.3 mm SL); Oahu, Haleiwa River, BPBM 15432 (2: 101.1–109.3 mm SL); Oahu, Honolulu, BPBM 4201
(2: 98.5–154.0 mm SL); Oahu, Honolulu, ANSP 69742 (148.5 mm SL; paratype of M. hawaiiensis); Oahu, Honolulu,
ANSP 88443 (103.1 mm SL); Oahu, Honolulu, ANSP 86807 (90.5 mm SL); Molokai, northwest side of island, BPBM
23814 (2: 91.6–103.8 mm SL); Molokai, northwest side of island, BPBM 24134 (116.9 mm SL).
FIGURE 7. Microcanthus strigatus, in situ photograph from Omeo Wreck, Coogee, Western Australia. The fish species in the
background is the pempherid Pempheris klunzingeri. Photograph by R. Turnbull.
Microcanthus joyceae Whitley
East-Australian Stripey
Figures 2C, 3B1, 4, 8–11; Table 2
Chaetodon strigatus [non Cuvier 1831].—Steindachner 1866: 435 (Port Jackson, Australia).—Macleay 1881: 387 (Port Jack-
son, New South Wales).—Ogilby 1886: 16 (Clarence River, New South Wales; not distribution or synonymy).
Neochaetodon vittatus [non Castelnau 1873].—Castelnau 1879: 350 (list, Port Jackson, Australia).
Microcanthus strigatus [non Chaetodon strigatus Cuvier 1831].—Cockerell 1915: 43 (Queensland, description of scales).—
McCulloch 1929: 248 (New South Wales distribution only; not synonymy).—Gill & Reader 1992: 208 (Elizabeth Reef,
Tasman Sea).—Francis 1993: 162 (checklist, in part, eastern Australia, Lord Howe and Norfolk Islands only).—Kuiter
1993: 215 (distribution in part, colour photo).—Kuiter 1996: 204 (distribution in part, colour photo).—Randall et al. 1998:
216 (description, distribution in part, colour photo).—Johnson 1999: 738 (checklist).— Hoese & Bray 2006: 1324 (check-
list, in part, eastern Australian distribution only).
Microcanthus joyceae Whitley 1931: 111, pl. 13, figs 4–5 (type locality, Shellharbour, New South Wales, Australia; holotype
AMS IA.4012; Figure 8).—Whitley 1964: 46 (checklist).—Kuiter & Kuiter 2018: 188 (colour photos; distribution).
Microcanthus howensis Whitley 1931: 112, pl. 13, fig. 2 (type locality, Lord Howe Island; holotype AMS IA.4018).
TEA & GILL
54 · Zootaxa 4802 (1) © 2020 Magnolia Press
Diagnosis. Microcanthus joyceae shares similar body proportions and meristic counts to M. strigatus, but can be
distinguished from Microcanthus strigatus in having the fifth body stripe relatively straight, without an inflection,
and in lacking spots and short dashes on the breast and lower body (Figures 8, 9 & 11).
Description. Dorsal-fin rays XI,16 (15–17); anal-fin rays III,14 (13–14); pectoral-fin rays 16/16 (15–17); upper
procurrent caudal-fin rays 9 (8–9); lower procurrent caudal-fin rays 8 (7–9); total caudal-fin rays 32–35; diagonal
rows of scales in lateral series 56 (49–58); circumpeduncular scales 26 (26–28); gill rakers 16–17; branchiostegals
7. Frequency distributions of numbers of dorsal-, anal- and pectoral-fin rays, and numbers of circumpeduncular
scales and diagonal rows of scales in lateral series are presented in Table 2.
Body laterally compressed, moderately tall and roughly circular in lateral view, dorsal-fin origin to pelvic-fin
origin 54.1–59.8% SL; head small 31.6–35.1% SL; snout acute 7.8–10.8% SL; eye large 12.0–14.1% SL; interor-
bital region naked, 8.3–11.4% SL in width.
As percentage of SL (based on 25 specimens, 61.7–112.2 mm SL): predorsal length 44.2–51.5; prepelvic length
43.0–49.5; dorsal-fin origin to pelvic-fin origin 54.1–59.8; pelvic-fin origin to anal-fin origin 27.6–33.6; dorsal-fin
origin to anal-fin origin 65.5–72.7; spiny dorsal-fin base length 35.3–44.4; soft dorsal-fin base length 22.2–30.3;
anal-fin origin to dorsal-fin terminus 36.9–43.6; anal-fin base length 21.2–29.6; mid-dorsal fin to anal-fin origin
49.9–59.1; dorsal-fin terminus to dorsal end of caudal peduncle 8.7–11.0; anal-fin terminus to ventral end of caudal
peduncle 6.9–10.1; anal-fin terminus to dorsal end of caudal peduncle 15.9–18.6; dorsal-fin terminus to ventral end
of caudal peduncle: 16.3–19.9; first anal-fin spine 7.2–10.7; second anal-fin spine 16.2–22.4; third anal-fin spine
11.1–15.0; pectoral-fin length 24.4–27.7; pelvic-fin length 24.7–30.6; pelvic-fin spine 13.9–17.2.
Etymology. The species is named after Joyce K. Allan, who provided Whitley with illustrations of this species
for his original description. To be treated as a noun in the genitive case. While Whitley did not provide a common
name in his description, he alluded to its vernacular name, the “Stripey,” commonly used by locals in New South
Wales, Australia. Since the use of this name is pervasive throughout the region, we choose to retain it in part as the
common name, proposing the usage of “East-Australian Stripey” instead to distinguish M. joyceae from M. striga-
tus.
Distribution and habitat. Microcanthus joyceae is known from the eastern coast of Australia, from southern
Queensland to New South Wales, reaching its southernmost limit at the southern border of New South Wales. It
also occurs in New Caledonia, Lord Howe Island, and Norfolk Island (see Remarks; Figure 4). Juveniles and young
adults are often seen in rock pools and rocky shores at depths of up to 5 m (Figures 9 & 10). Adults are more com-
monly seen near rocky reefs, though are common in harbours, embankments, and under piers, where they occur in
large groups (Figure 11).
Remarks. In the original description of Microcanthus joyceae, Whitley (1931) made note of the difference in
stripe pattern, and the smaller overall size in comparison with M. strigatus from Asia. He further commented that
M. joyceae attains a maximum size of 150 mm, compared with the maximum size of 200 mm in M. strigatus. In
examination of specimens of M. joyceae (n = 25), our largest specimens measured 108.5 mm (Byron Bay, NSW;
AMS IB. 2518) and 112.2 mm (Lord Howe Island, NSW; AMS I.1797–1798), compared with the largest from East
Asia (n = 38) at 157.3 mm (Kagoshima, Japan; KAUM-I. 80597). While there is an apparent correlation in size dif-
ferences, we cannot discount the possibility of sampling bias. Results from a detailed morphological study, however,
confirms Whitley’s observation in that M. joyceae lacks the inflected anal-fin stripe and spot pattern on the lower
abdomen frequently observed in M. strigatus (Tea et al. 2019).
In the same publication, Whitley (1931) treated Microcanthus from Lord Howe Island as a separate species, M.
howensis, primarily on the basis of having thinner stripes that extend only half-way across the soft-dorsal and anal
fins. Our morphological data set for specimens of the southwest Pacific contains three Lord Howe Island individuals
(AMS I.1797–1798), including the holotype of M. howensis (AMS IA.4018), examination of which revealed no ap-
parent differences in meristic, morphometric, or coloration characters. Similarly, photographs of Lord Howe Island
individuals taken in the field showed no differences from M. joyceae in colour pattern, disagreeing with Whitley’s
description. However, given the morphologically cryptic nature of this group and the lack of comparative genetic
material from this region, we refrain from commenting on the status of M. howensis until more material becomes
available. We provisionally treat M. howensis as a synonym of M. joyceae, based on the geographic proximity of
Lord Howe Island to mainland eastern Australia.
REVISION OF THE GENUS MICROCANTHUS Zootaxa 4802 (1) © 2020 Magnolia Press · 55
FIGURE 8. Microcanthus joyceae, holotype, AMS-IA. 4012, 86.5 mm SL, Shellharbour, New South Wales, Australia. Note the
lack of a prominent inflection on the lower anal-fin stripe. Photograph by Y.K. Tea
FIGURE 9. Microcanthus joyceae, in situ photograph from Shelly Beach, Manly, New South Wales, Australia. Note the anal-fin
stripe without a downward inflection, and the lack of spots on the lower abdomen. Photograph by E. Schlogl.
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56 · Zootaxa 4802 (1) © 2020 Magnolia Press
FIGURE 10. Newly settled recruit of Microcanthus joyceae, ca. 12 mm SL, in situ photograph from Forresters Beach, New
South Wales, Australia. Juveniles often recruit in rock pools. Photograph by A.C. Gill.
FIGURE 11. Microcanthus joyceae, in situ photograph from Fly Point, Port Stephens, New South Wales, Australia. Photograph
by: E. Schlogl.
Material examined. NEW SOUTH WALES, AUSTRALIA: Lake Macquarie, Swansea Channel, Pelican, AMS
I.48994-001 (11: 61.7–72.8 mm SL); Byron Bay, AMS IB.2518 (108.5 mm SL); Kingscliff, Cudgera Creek, AMS
REVISION OF THE GENUS MICROCANTHUS Zootaxa 4802 (1) © 2020 Magnolia Press · 57
I.41846-001 (4: 19.5–41 mm SL, cleared and stained); Lord Howe Island, AMS IA.4018 (51.3 mm SL; holotype
of M. howensis); Lord Howe Island, AMS I.1797–1798 (2: 92.7–112.2 mm SL); Shellharbour, AMS IA.4012 (86.5
mm SL; holotype of M. joyceae); QUEENSLAND, AUSTRALIA: eastern tip of Sabina Point, AMS I.34301-015
(2: 76.9–97.0 mm SL); Moreton Bay, AMS IB.6348 (92.5 mm SL); Wide Bay, AMS I.10989 (2: 77.9–104.5 mm
SL); One Tree Island, AMS I.20463-027 (4: 82.1–89.4 mm SL).
TABLE 2. Frequency distributions for selected meristic characters of species of Microcanthus. (–) denote missing data.
Dorsal segmented rays Anal segmented rays
15 16 17
x
S.D. 13 14 15
x
S.D.
M. joyceae 1 23 5 16.1 0.44 2 27 – 13.9 0.26
M. strigatus 2 54 10 16.1 0.41 4 60 2 14.0 0.30
Pectoral rays* Circumpeduncular scales
14 15 16 17
x
S.D. 26 27 28 29 30
x
S.D.
M. joyceae – 4 53 1 15.9 0.29 12 – 13 – – 27.0 1.02
M. strigatus 1 15 114 2 15.9 0.38 25 – 31 – 8 27.5 1.34
Scales in lateral series*
48 49 50 51 52 53 54 55 56 57 58 59
x
S.D.
M. joyceae – 1 3 2 5 7 8 6 6 3 1 – 53.8 2.15
M. strigatus 5 5 8 16 23 20 21 10 11 – 3 1 52.8 2.27
*indicates characters that include bilateral counts.
Acknowledgements
The authors thank Mark McGrouther, Amanda Hay, and Sally Reader (AMS), Mark Sabaj, and Maria Hernandez
(ANSP), Arnold Suzumoto, Richard Pyle, and Loreen O’Hara (BPBM), Hiroshi Senou (KPM), Hiroyuki Motomura
(KAUM), Glenn Moore, and Mark Allen (WAM) for variously providing assistance, curatorial support, and speci-
men loans from their respective institutions. Sascha Schulz, Christopher Mark, Erik Schlogl, Shigeru Harazaki,
and Ray Turnbull provided excellent photographs used in this study. The authors extend their sincerest gratitude to
Bruce Carlson and Marj Awai for tracking down specimens of Microcanthus from Hawaii, as well as for providing
valuable information of their distribution through personal communication. The authors also thank Lynne Parenti
and Diane Pitassy (USNM) for providing tissue samples of Hawaiian Microcanthus. The tissue sample was acquired
under the MarineGEO Hawai’i 2017 project to survey the fishes of Kaneohe Bay, Hawaii. We thank MarineGEO
Hawai’I Mary Hagedorn, Director, the Smithsonian Conservation Biology Institution, and the Hawai’I Institute of
Marine Biology. We also thank Simon Ho and Nathan Lo for providing helpful comments on the early drafts of the
manuscript. The submitted manuscript was improved by reviews provided by Carole C. Baldwin, Seishi Kimura
and an anonymous reviewer.
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