Phylogeny and Taxonomic Revision of Nuchequula Whitley 1932 (Teleostei: Leiognathidae), with The Description of a New Species

2007·3 MB·English

by  Prosanta Chakrabarty

PUBLISHED BY THE AMERICAN MUSEUM OF NATURAL HISTORY
CENTRAL PARK WEST AT 79TH STREET, NEW YORK, NY 10024
Number 3588, 25 pp., 10 figures, 4 tables September 6, 2007
Phylogeny and Taxonomic Revision of Nuchequula
Whitley 1932 (Teleostei: Leiognathidae), with the
Description of a New Species
PROSANTA CHAKRABARTY1 AND JOHN S. SPARKS1
ABSTRACT
Nuchequula Whitley 1932, previously considered a subgenus of Leiognathus Lacepe`de 1802, is
elevated to generic rank. Nuchequula is diagnosed by the presence of a distinct saddle-shaped
nuchalmarkingandbythepresenceofapigment-free,mitten-shapedregionposteroventraltothe
pectoral-finbase.Thegenuscomprisesfivespecies,N.blochii,N.pan,N.nuchalis,N.decora,and
a new species described herein. Nuchequula mannusella, new species, is distinguished from its
congenersbya unique pigmentationpattern onthe dorsalfin andmorphology ofthe lower jaw.
Redescriptionsareprovidedfortheotherspecies.Aphylogeneticanalysisbasedonmorphological
characters,includingfeaturesofthelight-organsystem,indicatesthatNuchequulaismonophyletic.
INTRODUCTION (SparksandDunlap,2004;Sparksetal.,2005).
Complicatingeffortstoclarifythetaxonomyof
Leiognathidae is in need of taxonomic re- thegroupisthefactthat,formanyspecies,type
vision. To date, nearly 80 species have been specimens were either never deposited or have
described; however, only 40 are currently subsequently been lost. The original descrip-
recognized as valid (not including fossil taxa). tionsofmanyponyfishspecies,includingthose
Recent family-level phylogenetic studies have of Cuvier and Valenciennes who described
demonstrated that the largest included genus, numerousleiognathids,atbestconsistofafew
Leiognathus,isnotmonophyletic(Ikejimaetal., sentencesrestrictedtoexternalfeatures(noneof
2004; Sparks and Dunlap, 2004; Sparks et al., which are apomorphic), but often comprise
2005).Therefore,thereisaneedtodescribenew only a footnote providing a new name in
genera to recognize a monophyletic taxonomy referencetoanillustrationfromanothersource.
1Division of Vertebrate Zoology (Ichthyology), American Museum of Natural History (PC: [email protected];
JSS:[email protected]).
CopyrightEAmericanMuseumofNaturalHistory2007 ISSN0003-0082
2 AMERICAN MUSEUMNOVITATES NO. 3588
Theabsenceoftypematerialandtherudimen- plague the family. Only through careful study
tary nature of many original species descrip- ofthename-bearingtypes,consultationofthe
tionshaveledtotheproliferationofnomencla- original species descriptions, and an under-
tural problems in the literature. Moreover, the standing of the relationships among species
information provided for species in regional can these taxonomic problems be remedied.
faunal inventories (e.g., Food and Agriculture Recently, family-level phylogenetic analyses
Organization species identification guides) is have provided a better understanding of the
oftennotbasedonreferencetotypematerialor diversity of leiognathids (Ikejima et al., 2004;
originaldescriptions(SparksandChakrabarty, SparksandDunlap,2004;Sparksetal.,2005).
inreview). These phylogenetic studies have also helped
These nomenclatural problems contribute elucidate the limits and relationships of pony-
not only to frequent misidentifications but fish genera, and have revealed a great deal of
also to the creation of ‘‘wastebasket’’ species. variationintheLOSatthegenericandspecies
These taxa frequently comprise multiple spe- levels. Leiognathids traditionally have been
cies identified under a single name because arrayed in three genera, with the majority of
diagnostic characters have been poorly de- species placed within Leiognathus Lacepe`de
fined, or not defined at all. Many of these 1802; however, Leiognathus was not recovered
‘‘wastebasket’’ species are described as excep- as monophyletic in any recent phylogenetic
tionallywidespreadindistribution,despitethe study. As a result, Sparks et al. (2005) di-
factthatconsistentmorphologicalvariationis agnosed two new genera, Photopectoralis and
reported among various geographic popula- Photoplagios(basedonfeaturesoftheLOS),as
tions. Consistent geographic variation among a first step toward solving the paraphyly of
allopatric populations should be considered Leiognathus and clarifying taxonomy within
evidence for the presence of undescribed the assemblage. Two other clades, both for-
species that are endemic to a portion of the merly included in Leiognathus, remain with-
so-called widespread species’ range. These out diagnoses and are distinguished from
‘‘wastebasket’’ species have essentially taken Leiognathus sensu strictu by being placed in
on a gestalt identity of individual researchers quotes(i.e.,‘‘Leiognathus’’).CladeGofSparks
in the literature, an identity that is associated et al.’s (2005) phylogeny was recovered as the
with neither the type specimens nor the sister group to Photoplagios and is, in part,
original species descriptions (Sparks and recognized herein as Nuchequula. A phyloge-
Chakrabarty, 2007). netic analysis of Clade G and Photoplagios is
Superficially, leiognathids are rather non- included to further explore and clarify the
descriptsilveryfishesthatpossessfewexternal relationshipswithinthisassemblage.
features that can be used to distinguish Whitley (1932) described Nuchequula as
species. Internally, leiognathids possess a un- a subgenus of Eubleekeria Fowler 1904 to
ique light-organ system (LOS), consisting of include E. (Nuchequula) blochii and E. (N.)
acircumesophageallightorganandassociated nuchalis. Nuchequula was subsequently synon-
structures to facilitate both the transmission ymized with Leiognathus Lacepe`de 1802 by
and occlusion of bacterially generated lumi- James (1975). Whitley (1932) distinguished
nescence from the light organ. The LOS is Nuchequula from the subgenus Eubleekeria as
highly variable among species and between having ‘‘depth more than 2 in length and
the sexes (Sparks et al., 2005). Internal sexual having a dark nuchal mark’’ (versus ‘‘depth
dimorphism associated with the LOS and less than, or about, 2 in length with no dark
related anatomy has been little explored mark on nape’’). Whitley (1932) also desig-
among leiognathids (Haneda, 1940; McFall- nated Equula blochii as the type species of
Ngai and Dunlap, 1984; Sparks et al., 2005). Nuchequula. It is unclear why Whitley (1932)
The superficial external similarity of leio- selected E. blochii as the type species, because
gnathids, rudimentary original descriptions it was one of the few species described at the
for many species, and propagation of mis- time that he did not examine. His choice may
identifications in the literature have all con- have been due to the fact that Equula blochii
tributedtothemanytaxonomicproblemsthat Valenciennes, in Cuvier and Valenciennes,
2007 CHAKRABARTY AND SPARKS:REVISION OFPONYFISH NUCHEQUULA 3
1835 was the oldest available name for any
leiognathid species reported to have a nuchal
spot (Day, 1875). Notably, a nuchal marking
is not mentioned by Valenciennes in the
original description of E. blochii. The alco-
hol-preserved syntypes of E. blochii (MNHN
A-6757, 73.0 mm SL; MNHN A6759, 67.1
mm SL) have lost much of their original
pigmentationinpreservation;however,adark
brown triangular marking remains beneath
thenuchalspine.Whitley(1932)alsoplacedE.
nuchalis in Nuchequula, and in contrast to the
information provided for E. blochii, he pro-
Fig.1. LandmarksusedforPCA:(1)rostraltip
vides a description of the specimens he
ofpremaxilla;(2)posteriorendofnuchalspine;(3)
examined. anterior insertion of dorsal fin; (4) posterior in-
Herein we continue our taxonomic studies sertion of dorsal fin; (5) dorsal insertion of caudal
of Leiognathidae with the resurrection and fin;(6)midpointofcaudalborderofhypuralplate;
revision of Nuchequula Whitley 1932. Nuche- (7) ventral insertion of caudal fin; (8) posterior
quula includes N. blochii, N. pan, N. nuchalis, insertionofanalfin;(9)anteriorinsertionofanalfin;
(10) dorsal base of pelvic fin; (11) ventral end of
N.decora,andanewspeciesdescribedherein.
lowerjawarticulation;(12)posteriorendofmaxilla;
We address the taxonomy of the species
(13) anterior margin through midline of eye; (14)
included in Nuchequula, with careful consid-
posteriormarginthroughmidlineofeye;(15)dorsal
erationofboththeavailabletypematerialand endofopercle;(16)dorsalbaseofpectoralfin.Base
theoriginalspeciesdescriptions.Forspeciesin figuremodifiedfromNelson(2006).
whichtheoriginaldescriptionsdonotprovide
relevant diagnostic features and for which we graphs. The terminal dorsal-fin and anal-fin
lackfreshmaterial(e.g.,N.blochii,N.decora), rays,whicharebranchedtothebaseofthefin,
we defer to subsequent redescriptions of these arecountedasasingleelement.Poredscalesin
species from other authors, provided that the lateral line are counted in series from the
those descriptions are based on topotypic dorsalmarginofthegillopeningtothecaudal
material and are in agreement with the type flexure. Scale counts should be interpreted as
series. approximations, due to high intraspecific
variability, irregular arrangement, and the
MATERIALS AND METHODS deciduous nature of ponyfish scales in preser-
vation, and because small scale size and the
Osteologicalfeaturesofthenewspeciesand degree to which scales are embedded make
relatedtaxawereexaminedusingradiographs, accurate counts problematic.
specimens clearedandstained(C&S)forbone For the Principal Component Analysis
and cartilage (following Taylor and Van (PCA)ofshape,digitalimagesweretakenfrom
Dyke,1985),anddryskeletal(S)preparations. the left side of each specimen. Only specimens
Comparative materials are listed in Material that were preserved unbent and of adult size
Examined.Lightorganswereexaminedinsitu were used in this analysis. Landmarks (puta-
or isolated to permit detailed morphological tively homologous points on anatomical struc-
comparisons. Morphometric measurements tures)werechosentobestrepresenttheexternal
were recorded to the nearest 0.1 mm using shape of the body (fig. 1). The program
dial calipers. Standard length (SL) is used TPSDIG2 (Rohlf, 2006) was used to digitize
throughout. Vertebral counts exclude the ural thelandmarksontheimages.GeneralizedLeast
centrum (5 last half-centrum). Following Squares(GLS)Procrustessuperimpositionwas
Hubbs and Lagler (2004), the first caudal performedtoremovesizefromthedata.Inthe
vertebra is here defined as the first vertebra optimal superimposition, the distance mini-
bearing a definite hemal spine. Vertebral and mized is the Procrustes distance, calculated as
fin-spine/raycountswereobtainedfromradio- the square root of the summed squared
4 AMERICAN MUSEUMNOVITATES NO. 3588
distances between homologous landmarks explains 30% of the variation among speci-
(Goodall, 1991; Rohlf and Slice, 1990). This mens, whereas PC2 explains 17%, and PC3
superimposition, and the PCA, was performed explains 12%. PC1 largely explains the varia-
usingPCAGEN(Sheets,2001). tion related to increased body depth, elonga-
The phylogenetic analysis was conducted in tion ofthe head, and shorteningof thecaudal
NONA (Goloboff, 1998) via the WINCLADA peduncle. Nuchequula nuchalis is highly vari-
(Nixon, 2000) interface. For the phylogenetic able with regard to these shape elements, and
analysis, 15 morphological features were specimens are scattered between both ex-
simultaneously analyzed under the optimality tremes along PC1. The types of N. blochii
criterion of parsimony (200 random addition and N. pan are similarly elongate and do not
replicatesoftreebisection–reconnection),with overlap with any individuals of N. decora or
all transformations given equal weight. Only the new species along PC1. There is overlap
unambiguously optimized morphological among N. decora, N. nuchalis, and the new
transformations are used to diagnose clades. species along PC1. PC2 explains much of the
variation due todecreased head depth, partic-
ularly due to shortening in the area between
INSTITUTIONAL ABBREVIATIONS
the orbit and the posterior margins of the
AMNH American Museum of Natural maxilla and lower jaw. PC2 also explains
History,New York, NY variationduetoincreasedbodydepthbetween
AMS AustralianMuseum, Sydney thenuchalareaandthedorsal-fininsertion,as
ASIZ Academica Sinica Institute of well as the decreased distance between the
Zoology, Taipei pelvic- and anal-fin insertions relative to each
BMNH British Museum of Natural History,
other and the anterior portion of the body.
London
Nuchequula nuchalis and the new species do
CAS California Academy of Sciences, San
not overlap along PC2. Nuchequula nuchalis
Francisco, CA
hasashallowerlowerjawandmoreanteriorly
CUMZ Chulalongkorn University Museum
situated pectoral-, pelvic-, and dorsal-fin
of Zoology,Bangkok
FRLM Fisheries Research Laboratory, Mie origins than the new species. Individuals of
University,Mie-ken Nuchequuladecoraareintermediateandslight-
LACM Los Angeles County Museum of ly overlapping with both N. nuchalis and the
Natural History,LosAngeles, CA new species along PC2.
MCZ Museum of Comparative Zoology, The phylogenetic analysis of morphological
Cambridge, MA features (table 1) recovered two equally most
MNHN Muse´um National d’Histoire Natur- parsimonious trees with tree lengths of 24,
elle,Paris
consistency indices of .79, and retention
NMW Naturhistorisches Museum, Wien
indices of .90. A strict consensus of these
(Vienna)
two topologies is presented in figure 3.
QM Queensland Museum, Brisbane
Nuchequula and Photoplagios are both mono-
USNM NationalMuseumofNaturalHistory,
phyletic; however, the relationship among
Smithsonian Institution, Washington,
D.C. these clades and with ‘‘Leiognathus’’ daura
UMMZ University of Michigan Museum of and ‘‘L.’’ dussumieri remain unresolved, as
Zoology, AnnArbor, MI they were in the family-level phylogenetic
ZMB Universitat Humboldt, Museum fur study of Sparks et al. (2005).
Naturkunde, Berlin
ZMUC Kobenhavns Universitet Zoologisk
Museum, Copenhagen SYSTEMATIC ACCOUNTS
Nuchequula Whitley 1932
RESULTS
‘‘Leiognathus’’CladeG:Sparksetal.,2005(inpart)
Results of the PCA show that N. nuchalis,
N. blochii, N. pan, and the new species form TYPE SPECIES: Nuchequula blochii.
discrete groups on the plot of Principal INCLUDED SPECIES: N. pan, N. nuchalis, N.
Component (PC) 1 versus PC2 (fig. 2). PC1 decora, and N. mannusella n.sp.
2007 CHAKRABARTY AND SPARKS:REVISION OFPONYFISH NUCHEQUULA 5
Fig.2. PCAforspeciesofNuchequula(plotofPC1versusPC2).IndividualsofNuchequulamannusella.
are represented by black crosses; N. decora (all identified by Jones AMS I.22990002) is represented by
squares; and N. nuchalis is represented by triangles. Type specimens are represented by open shapes,
includingN.blochiisyntypes(rectangles)andN.panparatype(circle).(OnlyN.panparatypeUSNM276536
isincludedbecausetheholotypeandotherparatypesofthisspecieswereexaminedatCUMZandwerenot
availablefor this analysis.)
DIAGNOSIS: Members of Nuchequula are PARATYPES: AMNH 238754, 15 ex., 72.1–
distinguished from all other leiognathids by 90.1 mm SL; data as for holotype. AMNH
a darkly pigmented nuchal mark and by 238755, 16 ex., 62.9–89.7 mm SL; data as for
a pigment-free, mitten-shaped region ventral holotype.AMNH238756,15ex.,70.2–94.1 mm
and posterior to the pectoral-fin base. SL;dataasforholotype.AMNH238757,14ex.,
REMARKS: Sparks et al.’s (2005) ‘‘Clade 64.8–81.2 mmSL;dataasforholotype.AMNH
G’’ also included ‘‘Leiognathus’’ dussumieri 238758, 20 ex., 77.2–86.9 mm SL; data as for
and ‘‘L.’’ daura. We do not include these holotype. AMNH 238759, 9 ex., 82.1–95.4 mm
species in Nuchequula because the relation- SL;dataasforholotype.AMNH238760,13ex.,
ships of ‘‘L.’’ dussumieri, and ‘‘L.’’ daura 75.1–98.5 mmSL;dataasforholotype.AMNH
within Clade G remain unresolved and be- 238761, 1 ex., 71.2 mm SL; Taiwan: Hsinchu
cause both species lack the distinctive nuchal City: Motorway 3 north from Taichung, one-
marking that characterizes the genus. and-one-halfhoursfromTaichung,WestCoast
Hwy:FishingHarborinHsinchu:24u50955.40N,
120u55913.60E; local fisherman, Prosanta
Chakrabarty, Otto Jeng-Di Lee, John S.
Nuchequula mannusella, new species
Sparks, 20March 2006.AMNH 238762, 1 ex.,
figures 4, 5A, tables 2–3
53.4 mm SL; data as for holotype. AMNH
HOLOTYPE: AMNH 238753, 85.5 mm SL; 238763,1ex.,83.0 mmSL;dataasforholotype.
Taiwan:ChiayiCounty:TungshihFishMarket: AMNH 238764, 1 ex., 88.9 mm SL; data as
23u27910N, 120u08919.30E; TW-6-2006; Pro- for holotype. AMNH 238765, 29 ex., 73.6–
santa Chakrabarty, Joker K.H. Chiu, John S. 100.9 mm SL; data as for holotype. ASIZP
Sparks,22March2006. 0062322,1ex.,76.2 mmSL;Taiwan:Fenggang:
6 AMERICAN MUSEUMNOVITATES NO. 3588
TABLE1
Morphological TransformationsUsed in thePhylogenetic Analysis ofNuchequulaSpecies (see fig.3)
C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11 C12 C13 C14 C15
L.equulus 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
L.robustus 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
P.elongatus 0 2 1 0 1 2 1 1 1 0 1 1 1 1 0
P.rivulatus 0 2 1 0 1 2 1 1 1 0 1 1 1 1 0
P.leuciscus 0 1 1 0 1 3 1 1 0 1 0 1 1 1 0
P.stercorarius 0 2 1 0 1 3 1 1 0 0 1 1 1 1 0
P.antongil 0 1 1 0 1 3 1 1 1 0 1 1 1 1 0
L.dussumeri 0 1 1 0 0 0 0 1 0 0 0 0 0 0 0
L.daura 0 1 1 0 0 4 0 1 0 0 0 0 0 0 1
N.pan 1 1 0 1 0 5 0 1 0 0 1 0 0 0 1
N.nuchalis 1 1 0 1 0 4 0 1 0 0 1 0 0 0 1
N.blochii 1 1 0 ? 0 4 0 1 0 0 0 0 0 0 1
N.decora 1 1 1 1 0 0 0 1 0 0 0 0 0 0 0
N.mannusella 1 1 0 1 0 0 0 1 0 0 0 0 0 0 1
Characters:C15nuchalspot(05absent;15present);C25bodydepthaspercentageofstandardlength(05.50%;
15,40–50%;25,40%);C35lowerjawprofile(05concave;15straight);C45pigment-freemitten-shapedregion
nearpectoralfin(05absent,scatteredmelanophoresinarea;15present);C55concavityaboveorbit(05present;15
absent);C65pigmentationpatternondorsalflank(05zigzags,straight,orwavyverticallines;25circularshapes;35
irregularshapes;45absent;55horizontallines/stripes);C75translucentflankpatch(05absent;15present);C85
adultbodysize(05.150mmSL;15,150mmSL);C95seconddorsal-andanal-finspines(05robust;15feeble);
C105seconddorsal-finspine(05notconsiderablymoreelongatethanotherspines;15markedlyelongaterelativeto
otherspines);C115dorsal-finoriginrelativetopelvic-finorigin(05onverticalthroughpelvic-finorigin;15posterior
toverticalthroughpelvic-finorigin);C125lightorgandimorphicinsize(05absent;15present);C135dorsallobesof
lightorganhypertrophiedinmales(05absent;15present);C145clearingoflateralsilveryliningofgasbladderin
males(05absent;15present);C155dorsalfinmarkings(05absent;15present).
Pingtung: open sea, at 100 m depth: 22u269N, DESCRIPTION: Morphometric and meristic
120u389E; J.H. Wu, 1 March 2001. ASIZP data are presented in table 2, and other
0060823, 1 ex., 90.9 mm SL; Taiwan: comparative features are presented in table 3.
Kaoshiung: Shingda Harbor: open sea: Nuchequula mannusella is a moderately large
22u879N, 120u199E; G.J. Xia, 8 June 2000.SIO (maximum recorded length 101 mm SL),
06.261, 2 ex., 83.7–96.2 mm SL; data as for rhomboid-shaped ponyfish. The dorsal and
holotype. (Because much of this collection is ventralprofiles areequally convex. The great-
fromasinglemarketlocality,differentAMNH est body depth is reached at the vertical from
numberswereassignedtomaterialtoreflectthe the dorsal-fin origin to the pelvic-fin origin.
possibility that different vendors sold fish from There is a concavity above the orbit, formed
diversesources.) by the exposed rising dorsal aspect of the
DIAGNOSIS: Nuchequula mannusella is dis- supraoccipital crest (i.e., nuchal spine). The
tinguished from its congeners by a conspicu- dorsal-andpelvic-finoriginsarelocatedalong
ously deep lower jaw with a strongly concave thesamevertical.Theanal-finoriginislocated
profilethatissharplypointedventrally(versus at the vertical from the last (5 eighth) dorsal-
a slightly concave or straight lower jaw fin spine. The mouth is terminal and directed
profile). The black dorsal-fin marking of N. strongly ventrally when extended. The lower
mannusella is uniquely restricted to the ante- jaw is deep, and the lateral profile is strongly
rior edge of the fin, with some scattered concave. The lips are thin and only somewhat
melanophores in the dorsal-fin membrane fleshy. The posterior margin of the maxilla is
(versus a large blotch over a larger area on exposed, reaching the vertical through the
the dorsal fin or an absence of markings on anterior part of pupil and the dorsal portion
the dorsal fin). of the lower jaw articulation. The exposed
2007 CHAKRABARTY AND SPARKS:REVISION OFPONYFISH NUCHEQUULA 7
Fig.3. Strictconsensusoftwoequallymostparsimonioustopologiesbasedontheanalysisofmorphological
features.Thecharactermatrixispresentedintable1.Numbersonbranchescorrespondtoapomorphicfeatures
thatdiagnoseclades;numbersinparenthesesrepresentthestate,otherthan1.Solidbarsrepresentuniqueand
unreversedfeatures,whereasopenrectanglesrepresenthomoplasiouscharacters.
part of maxilla is nearly perpendicular with gill rakers present on the lower limb of the
the mouth when retracted. The eyes are large first gill arch; the rakers are sparsely dentic-
and circular (, 10% SL). The sensory pores ulated (i.e., bearing few teeth). The longest
around the orbit are moderately well de- rakersareaboutthelengthofthegilllamellae,
veloped; some pores posterior to the orbit whereas the shortest are about half the length
reach the preopercle. Sensory canals are also of the lamellae. There are 23 total vertebrae
present ventral to the orbit and dorsal to the (10 precaudal + 13 caudal).
mouth. Two long sensory canals are present Fins: The dorsal fin has VIII spines and 16
ventral to the nuchal spine. Two closely rays.Thefirstdorsal-finspineismuchshorter
apposed nasal pores are present anterior to than the other spines, and 15–20% of the
the orbit. The anterior nasal pore is smaller second spine. The length of the second and
and more rounded than the posterior pore. longest dorsal-fin spine is about 40% of body
The preopercular margin is strongly serrated depth and not conspicuously longer than the
along the ventral margin, with 20–25 spines. third or fourth spine. The second and third
The supraorbital ridge bears small spines. spines are more robust, particularly at the
Therearetwoshortandstoutpostnasalspines base,thantheremainingspines.Thethirdand
presentdorsaltotheorbitandposteriortothe fourth spines possess serrations facilitating
nasalpores.Thereare16elongateandslender interlocking with the preceding spine. The
8 AMERICAN MUSEUMNOVITATES NO. 3588
Fig. 4. Nuchequula mannusella, new species: (A) Holotype, AMNH 238753, 85.5 mm SL, Taiwan. (B)
Rightside of holotype. (C)Drawing of holotype.(D)Paratype, AMNH238759,94.1 mm SL,Taiwan.
anal fin has III spines and 14 rays. The first originoftheanalfin,andhaveoneassociated
anal-finspineismuchshorterthantheothers, spine. The caudal fin is deeply forked.
25–35% of the second. The second anal-fin Dentition: The teeth are villiform and
spineismorerobustthantheotherspines;itis arrayed in a narrow band of three to five
onlyslightlylongerthanthethirdandisabout poorly differentiated rows. The teeth in the
30% of body depth. The third anal-fin spine lower jaw are slightly recurved, whereas those
possesses serrations facilitating interlocking in the upper jaw are strongly recurved and
with the second spine. There is a sheath of almost parallel with the roof of the mouth.
asquamate tissue that covers the bases of the Squamation: As for all leiognathids, scales
spinous portions of the dorsal and anal fins. are highly deciduous, making accurate counts
Thepelvicfinsareshort,anddonotreachthe and observations problematic. The chest and
2007 CHAKRABARTY AND SPARKS:REVISION OFPONYFISH NUCHEQUULA 9
Fig. 4. Continued.
fins are asquamate. Some specimens possess about55scales.Theporesofthelaterallineare
scales on the cheek and in the interpelvic well developed. The lateral line is horizontal
region. There are scales present in the nuchal betweentheposterodorsalmarginoftheopercle
region and continuing to the ventrum (not to slightly beyond the pectoral-fin base. The
including the chest), which extend posteriorly laterallineisarchedslightlyfromthepectoral-
tothecaudalpeduncleandontothecaudalfin. finbaseposteriorlytothecaudalpeduncleand
Thelaterallineiscomplete,extendingfromthe ishorizontalonthecaudalpeduncle.
posterior edge of the opercle to the posterior Pigmentation in life: The entire body is
margin of the caudal peduncle, and includes silvery (see fig. 5A). The leading edge of the
10 AMERICAN MUSEUMNOVITATES NO. 3588
Fig.5. FreshmaterialfromTonshiFishMarket,Taiwan.(A)TwoparatypesofNuchequulamannusella,
new species. (B)Nuchequula nuchalis.