Zoological Studies 44(2): 210-218 (2005)

Validity of the Scorpionfish Genus Hipposcorpaena Fowler and a
Redescription of H. filamentosa Fowler (Scorpaeniformes:
Scorpaenidae)
Hiroyuki Motomura1,* and Hiroshi Senou2
1Ichthyology, Division of Aquatic Science, Australian Museum, 6 College Street, Sydney, New South Wales 2010, Australia
2Kanagawa Prefectural Museum of Natural History, 499 Iryuda, Odawara, Kanagawa 250-0031, Japan(Accepted March 2, 2005)

Hiroyuki Motomura and Hiroshi Senou (2005) Validity of the scorpionfish genus Hipposcorpaena Fowler anda redescription of H. filamentosa Fowler (Scorpaeniformes: Scorpaenidae). Zoological Studies 44(2): 210-218.
The validity of the poorly known monotypic scorpionfish genus Hipposcorpaena Fowler is confirmed, and H. filamentosa Fowler is redescribed. The genus is characterized by the following characters: dorsal fin with 12
spines and 9 soft rays; anal fin with 2 spines and 6 soft rays; pectoral fin with 14 rays; lower pectoral fin rays
slender, filamentous; longest ray extending well beyond vertical from posterior end of anal fin base; all dorsal
and anal fin soft rays (except last ray of each fin divided into 2 at base), and all pectoral and caudal fin rays
unbranched; head and body strongly compressed; body deep, depth 39.5%~41.2% of standard length; bodycovered with small cycloid scales; no palatine teeth; interorbital ridges present; tympanic spine present; posttemporal spine simple, lacking upper posttemporal spine; lower caudal fin with 1~4 distinct black spots, greaterin width than orbit diameter; mature adult size at least 35.2 mm SL.
http://www.sinica.edu.tw/zool/zoolstud/44.2/210.pdf
Key words: Scorpaenidae, Genus, Hipposcorpaena, Redescription, Hipposcorpaena filamentosa.

Fcollected by a local fisherman from Tayabas Bay
between Luzon I. and Boak I., Philippines, on 22
Feb. 2004, was subsequently registered at the
Kanagawa Prefectural Museum of Natural History,
Kanagawa, Japan, and identified as H. filamentosa. The specimen was in excellent condition,and several important characters, which had previously been overlooked, were identified, leading toour conclusion that Hipposcorpaena is a valid
genus.
Previous accounts of H. filamentosa lacked
accurate information on the coloration when fresh.
A color photograph of the newly collected specimen, taken by the 2nd author before formalin fixation, is included here.
This paper includes confirmation of the validity of the monotypic genus Hipposcorpaena, aredescription of H. filamentosa, descriptions ofowler (1938) described Hipposcorpaena filamentosa as a new genus and species on thebasis of a single specimen (USNM 98819, 29.4mm standard length) from the Philippines.
Subsequently, Eschmeyer et al. (1973) reexamined the holotype and reported the existence of a
2nd example of the species (USNM 168183, 31.1mm). Although they regarded Hipposcorpaena asa probable valid genus, Poss (1999) later included
the species in Rhinopias Gill, without explanation.
Only Eschmeyer et al. (1973) and Poss (1999)
have reported on specimens of this species since
its original description by Fowler (1938). Both of
the 2 known specimens are in very poor condition.
Thus, the generic (and specific) status and taxonomic characters of the species have remained
obscure.
A single example of an unusual scorpionfish,* To whom correspondence and reprint requests should be addressed. E-mail: motomurah@austmus.gov.au

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Motomura and Senou -- Validity of Hipposcorpaena

newly recognized diagnostic characters, and comments on sexual maturity and the shedding of the
cuticle in the species.

MATERIALS AND METHODS
Measurements follow Motomura (2004b, c).
Standard and head lengths are expressed as SL
and HL, respectively. The last 2 soft rays of thedorsal and anal fins are counted as single rays, aseach pair are associated with a single pterygiophore. Pectoral fin ray counts begin with theuppermost element. Longitudinal scale rows
include the vertical scale rows above the lateralline, taken from above the 1st pored lateral scale
to the caudal fin base (scale rows are irregular anddifficult to count). Pored lateral line scales thathave an external median tube are counted fromthe 1st pored scale near the upper end of the gill
opening to the pored scale on the posterior marginof the hypural plate. Gill raker counts are made on
the 1st arch, with the upper count given 1st (lower
counts include raker at angle).
Terminology of the head spines follows
Randall and Eschmeyer (2002). Sex of the newly
collected specimen (KPM-NI 13005, 35.2 mm SL)
was established by dissection of the abdomen on
the right side. Osteological characters were confirmed from radiographs. A redescription of thespecies is based on KPM-NI 13005, and the diagnostic characters proposed were confirmed in
USNM 168183. The holotype (USNM 98819) was
not available for examination. Institutional codes
follow Eschmeyer (1998).
Genus Hipposcorpaena Fowler, 1938
(Figs. 1-4)
Hipposcorpaena Fowler 1938: 71, fig. 31 (type species:
Hipposcorpaena filamentosa Fowler 1938; type by original
designation, also monotypic; gender: feminine).

Diagnosis: Dorsal fin with 12 spines and 9
soft rays; anal fin with 2 spines and 6 soft rays;
pectoral fin with 14 rays; lower pectoral fin rays
slender (not thickened), filamentous; longest ray ofpectoral fin extending well beyond vertical fromposterior end of anal fin base; all dorsal and anal
fin soft rays (except last ray of each fin divided into
2 at base), and all pectoral and caudal fin rays
unbranched; head and body strongly compressed;
body deep, depth 39.5%~41.2% of SL; body covered with small cycloid scales; no palatine teeth;

211

interorbital ridges present; tympanic spine present;
posttemporal spine simple, lacking upper posttemporal spine; lower caudal fin with 1~4 distinct blackspots, greater in width than orbit diameter; mature
adult size at least 35.2 mm SL.
Remarks: Fowler (1938: 71) proposed
Hipposcorpaena as a new monotypic genus for his
new species, H. filamentosa Fowler (1938: 72).
He stated that Hipposcorpaena“resembles
Taenianotus Lacepède, but with much deeper
body, very different physiognomy, well-separated
dorsals, and advanced ventrals”. In addition tothese differences, Hipposcorpaena differs from thelatter in having its body being covered with cycloid
scales (vs. scales reduced to small, widely scattered points in the latter; Poss 1999).
Although Eschmeyer et al. (1973) presumed
that Hipposcorpaena was probably valid andclosely related to Rhinopias Gill, Poss (1999)
included H. filamentosa in the latter genus. As
Eschmeyer et al. (1973) pointed out, H. filamentosa and species of Rhinopias are very similar toeach other in overall body appearance, and share
several characters: e.g., dorsal fin with 12 spinesand 9 soft rays, head and body strongly compressed, body depth 38%~54% of SL (range from
Poss 1999), body covered with cycloid scales, andno palatine teeth. Hipposcorpaena filamentosa
and species of Rhinopias are easily distinguishedfrom all other known genera of the Scorpaenidae,
by the above characters, except for the uncertain
monotypic genus Pogonoscorpius Regan (seedetails in Eschmeyer et al. 1973: 303-304, fig. 9).
It is likely that Poss (1999) treated them as a single genus (Rhinopias) on the basis of these characters.
Hipposcorpaena filamentosa was previously
known only from 2 specimens (USNM 98819, holotype, 29.4 mm SL and USNM 168183, non-type,31.1 mm SL). Because both specimens were inpoor condition (Eschmeyer et al. 1973, this study),
the latter appearing to have been dried out atsome time, some important specific characters
were overlooked. The recently collected specimen(KPM-NI 13005, 35.2 mm SL) was in excellent
condition, enabling the following comparisons.
The anal fin of Hipposcorpaena clearly
includes 2 spines and 6 soft rays, although Fowler(1938) gave the complement as“9”in the originaldescription and Eschmeyer et al. (1973) described
it as“total 81/2 and seem to be III + 51/2”, on thebasis of their reexamination of the holotype of H.
filamentosa. It is apparent that Fowler (1938)
counted the last 2 elements as separate rays anddid not distinguish spines from soft rays.

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Zoological Studies 44(2): 210-218 (2005)

Eschmeyer et al. (1973) correctly recognized thelast 2 elements as 11/ 2 (equivalent to 1 in thisstudy, see“Materials and Methods”), but misdetermined the ratio of spines to rays, probably
owing to the poor condition of the specimen.
Incidentally, Eschmeyer et al. (1973) commented
on problems regarding fin ray counts in genera
related to Rhinopias. Contrary to the condition in
Hipposcorpaena, all known species of Rhinopias
have 3 spines and 5 soft rays in the anal fin(Eschmeyer et al. 1973, Condé 1977, Randall and
DiSalvo 1997).
All dorsal and anal fin soft rays (except thelast ray of each fin which is divided into 2 at thebase) and all pectoral and caudal fin rays in
Hipposcorpaena are unbranched, whereas in
Rhinopias all dorsal and anal fin soft rays, lower
pectoral fin rays, and most caudal fin rays are
branched. The above-mentioned differences inanal fin spine numbers and soft ray condition(branched or unbranched) have been widely
regarded as diagnostic characters separating several genera within the Scorpaenidae, e.g., between
Neomerinthe Fowler and Pontinus Poey,
Dendrochirus Swainson and Pterois Oken, andParapterois Bleeker and Pterois (e.g., Eschmeyer
1969, Eschmeyer and Randall 1975, Motomura
2004a).
Osteological characters (head spines) in
Hipposcorpaena differ from those in Rhinopias inhaving the interorbital ridges (vs. absent or poorly
developed in the latter), a tympanic spine (vs.
absent), and a simple posttemporal spine, theupper posttemporal spine being absent (vs. both
upper and lower posttemporal spines present) (seeFig. 2).
Furthermore, the pectoral fin characteristics ofHipposcorpaena are distinctive among the
Scorpaeninae, with membranes between the lower
pectoral fin rays being strongly notched, extending
to 1/3~1/2 of the length of each upper adjacentray, the lower 7 rays thereby appearing filamentous (Fig. 3). The pectoral fin membranes in related genera are not strongly notched, reaching near
the tip of each ray. In addition, the lower pectoral
fin rays in Rhinopias are fleshy and thickened,
whereas those in Hipposcorpaena are not (Fig. 3).
Hipposcorpaena can be further distinguishedfrom Rhinopias by 14 pectoral fin rays (in all
known specimens vs. 15~18 rays in the latter;
Eschmeyer et al. 1973, Randall and DiSalvo
1997), the longest pectoral fin ray extending wellbeyond a vertical from the posterior end of the anal
fin base (vs. not reaching the middle of the anal finbase), and the lower caudal fin with distinct black
marking(s) (see Fig. 1 and Fowler 1938: fig. 31 vs.
absent). These characters appear to be speciesapplicable, however, judging from charactersaccorded to other genera of the Scorpaenidae.
As discussed above and presumed by°

Fig. 1. Hipposcorpaena filamentosa. KPM-NI 13005, mature female, 35.2 mm SL, Tayabas Bay, between Luzon I. and Boak I., thePhilippines.

213

Motomura and Senou -- Validity of Hipposcorpaena

Eschmeyer et al. (1973), Hipposcorpaena isapparently closely related to Rhinopias. However,the former shares some characters, not found in
Rhinopias, with another poorly known genus,
Pteroidichthys Bleeker (including 2 species; sensu
Poss 1999), such as the presence of unbranchedsoft rays in most fins (see Eschmeyer et al. 1973)
and the absence of the upper posttemporal spine(this study). In addition to the unique characters(see above) in Hipposcorpaena, that genus shares
several characters only with either Rhinopias or
Pteroidichthys, suggesting that Rhinopias andPteroidichthys also have a close relationship witheach other (see Eschmeyer et al. 1973).
Comparative material examined: Pteroidichthys amboinensis Bleeker: BPBM 36765, 42.5mm SL, east end of Maumere Bay, Flores,
Indonesia, 7~9 m depth, rotenone, coll. by B. C.
Russell on 7 Nov. 1991. Pteroidichthys noronhai(Fowler): USNM 98892, holotype of Pteropelor
noronhai, 32.3 mm SL, vicinity of Hong Kong (2133'N, 116 13'E), China, 183 m depth, coll. by RV
Albatross on 4 Nov. 1908, station no. 5310,
Albatross Philippine Expedition. Rhinopias
aphanes Eschmeyer: AMS IB. 7078, holotype,177.7 mm SL, off Nouméa, New Caledonia, 30 m
depth, coll. by Y. Merlet and M. R. Catala-Stucki.
Rhinopias cea Randall and DiSalvo: BPBM 31701,
148.0 mm SL, Rapa I., Austral Is., French
Polynesia, coll. by F. Reveil in May 1990.
Rhinopias eschmeyeri Condé: MZUVN 10475,

holotype, 148.1 mm SL, Mahébourg, Mauritius, 3m depth, coll. by L. P. Jauffret on 24 Sept. 1976.
Rhinopias frondosa (Günther): BMNH 1891.4.30.3,
holotype of Scorpaena frondosa, 146.2 mm SL,
Mauritius, coll. by M. Robillard (collection dateunknown, but before Aug. 1891). Rhinopias
xenops (Gilbert): BPBM 33504, 147.8 mm SL, off
Waikiki, Oahu, Hawaiian Is., 73 m depth, otter
trawl, coll. by P. S. Lobel on board RV Machias on
9 Feb. 1974.

Fig. 2. Head of Hipposcorpaena filamentosa in lateral view.
KPM-NI 13005, 35.2 mm SL. Numerous small papillae on thehead are not illustrated. Scale bar = 5 mm.

Fig. 3. Pectoral fin of Hipposcorpaena filamentosa in lateralview. KPM-NI 13005, 35.2 mm SL. Scale bar = 5 mm.

°°

Hipposcorpaena filamentosa Fowler, 1938
(Figs. 1-4)
Hipposcorpaena filamentosa Fowler 1938: 72, fig. 31 (typelocality: 1.5 miles off Linao Point, Davao Gulf, Philippines,
7 04'48''N, 125 39'38''E, Albatross station D. 5253);
Eschmeyer 1973: 304 (comments on the holotype data of
H. filamentosa).
Rhinopias filamentosa; Poss 1999: 2301 (listed in key only).

°°

Material examined: KPM-NI 13005, mature
female, 35.2 mm SL, Tayabas Bay between Luzon
I. and Boak I. (ca.13 30'N, 121 30'E), Philippines,
20 m depth, coll. by a local fisherman on 22 Feb.
2004, and then purchased by K. Ishigaki for H.
Senou; USNM 168183, 31.1 mm SL, off Jolo I. (0603'45''N, 120 57'00''E), Philippines, 37 m depth, 5Mar. 1908, Albatross station D. 5174.
Diagnosis: As for genus.
Description: Proportional measurements aspercentages of SL and HL of the specimens of

°

°

°

°

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Zoological Studies 44(2): 210-218 (2005)

Hipposcorpaena filamentosa are given in Table 1.
Dorsal fin with 12 spines and 9 soft rays; all rays,
except last soft ray divided into 2 at base,unbranched; 1st spine length 1/2 that of 2nd spine;
2nd spine longest, length greater than upper jaw
length; 2nd to 11th spines progressively shorter;
length of 11th spine 2.7 in last spine; interspinous
membranes of adjacent dorsal fin spines reachingtips of posterior spines, except 2nd, 11th and 12th
spines; 4th and 5th soft rays equally longest;
5th~9th soft rays progressively shortening; intersoft-rayed membrane reaching tips of posterior
rays; posterior branch of last soft ray joined bymembrane to caudal peduncle for less than 1/3 its
length. Anal fin with 2 spines and 6 soft rays; allrays, except last soft ray divided into 2 branches atbase, unbranched; 1st spine 2.4 in 2nd spine;
1st~4th soft rays progressively lengthening, 4thlonger than longest dorsal fin soft ray; 4th~6th softrays progressively shortening; posterior branch oflast soft ray joined by membrane to caudal peduncle for less than 1/6 its length; membranes
between rays weakly notched. Pectoral fin with 14
rays on each side of body, all rays unbranched;
2nd~7th rays progressively shortening, 9th ray
longest, length greater than head length; 9th tolowermost rays progressively shortening; membranes between 2nd and 7th rays reaching tip ofeach ray; membranes between 7th and lowermost
rays strongly notched, membranes between 9th

Table 1. Morphometric characters of Hipposcorpaena filamentosa, expressed as percentages of standard
and head lengths

Standard length (mm)Percent of standard length
Body depth
Body width
Head length
Snout length
Orbit diameter
Interorbital width1
Interorbital width2
Upper jaw length
Postorbital length
Predorsal fin length
Preanal fin length
Prepelvic fin length
1st dorsal fin spine length
2nd dorsal fin spine length
3rd dorsal fin spine length
4th dorsal fin spine length
5th dorsal fin spine length
6th dorsal fin spine length
7th dorsal fin spine length
8th dorsal fin spine length
9th dorsal fin spine length
10th dorsal fin spine length
11th dorsal fin spine length
12th dorsal fin spine length
1st dorsal fin soft ray length
2nd dorsal fin soft ray length
3rd dorsal fin soft ray length
4th dorsal fin soft ray length
5th dorsal fin soft ray length
6th dorsal fin soft ray length

KPM-NI
13005

USNM
168183

35.2

31.1

39.5
16.8
48.0
24.1
9.9
6.3
9.1
19.0
17.0
41.5
71.6
40.3
11.4
22.7
21.9
18.5
15.1
13.6
12.8
11.1
8.5
5.4
5.1
13.9
16.2
17.6
17.9
19.3
19.3
19.0

41.2
13.5
46.9
21.2
10.9
6.4
8.7
18.0
17.4
39.9
68.8
38.6
22.5
19.6
12.9
9.3
6.1
5.5
14.1
-

KPM-NI
13005

USNM
1681837th dorsal fin soft ray length
8th dorsal fin soft ray length
9th dorsal fin soft ray length3
9th dorsal fin soft ray length4
1st anal fin spine length
2nd anal fin spine length
1st anal fin soft ray length
2nd anal fin soft ray length
3rd anal fin soft ray length
4th anal fin soft ray length
5th anal fin soft ray length
6th anal fin soft ray length3
6th anal fin soft ray length4Pectoral fin length
Pelvic fin spine length
1st pelvic fin soft ray length
2nd pelvic fin soft ray length
3rd pelvic fin soft ray length
4th pelvic fin soft ray length
5th pelvic fin soft ray length
Caudal fin length
Caudal peduncle length
Caudal peduncle depth

15.1
12.8
10.2
8.0
4.3
10.2
16.2
20.2
23.6
24.1
23.0
19.3
15.3
49.4
14.5
19.3
21.9
21.6
18.5
14.2
40.9
14.5
9.7

47.9
14.1
10.3

Percent of head length
Snout length
Orbit diameter
Interorbital width1
Interorbital width2
Upper jaw length
Postorbital length
3rd dorsal fin spine length

50.3
20.7
13.0
18.9
39.6
35.5
45.6

45.2
23.3
13.7
18.5
38.4
37.0
-

1Between the posterior ends of the preocular spine bases; 2between the vertical midline of the eyes; 3anterior element; 4posterior ele-

ment; -, broken.

215

Motomura and Senou -- Validity of Hipposcorpaena

and lowermost rays extending to 1/3~1/2 length ofeach upper adjacent ray; lower 7 rays filamentous.
Pelvic fin with 1 spine and 5 soft rays, 1st~3rd softrays branched, remaining rays unbranched; 2ndsoft ray longest, slightly longer than upper jaw
length. Caudal fin with 14 rays, all unbranched;
8th ray longest, slightly greater than body depth.
Longitudinal scale rows ca. 54; pored lateralline scales 21; scale rows between origin of lastdorsal spine and lateral line 8; scale rows between
origin of 1st anal fin spine and lateral line ca. 20.
Gill rakers on upper limb 4, on lower limb 14,
including 6 rakers on hypobranchial; gill rakers
short and spinous, longest raker on 1st gill archless than 1/4 length of longest gill filament; 4th gillslit closed by membrane. Vertebrae 24.
Swimbladder absent.
Body and head strongly compressed, headwidth narrower than greatest body width. Body
moderately deep, deepest at origin of 2nd dorsal
fin spine. Head large, length greater than body
depth. Posterior lacrimal spine with a large, rounded tentacle, its anterior margin corrugated, lengthof tentacle approximately equal to orbit diameter.
No tentacle on supraocular spine. A pair of tentacles projecting from anterior surface of lip at symphysis of upper jaw, each tentacle divided into 2
major branches. No tentacle on anterior nostril. A
small tentacle on cheek. Five circular tentacles
along preopercular margin; lowermost largest,
elliptical, length slightly less than pupil diameter;
uppermost on lowermost preopercular spine.
Three tentacles on each side of ventral surface ofmandible; anteriormost tentacle simple, tiny, located anterior to 1st dentary pore; 2nd tentacle simple, long, slender, located between 1st and 2nd
dentary pores; 3rd tentacle largest, length slightly
less than depth of posterior margin of maxilla, withseveral appendages. Small elliptical or triangularfleshy tentacles on outer part of eye membrane.
Very few obvious tentacles on body, except on lateral line scales; 4 large tentacles, somewhat shorter than orbit diameter, associated with lateral line
scales. Tiny tentacles along all dorsal fin spines
and soft rays, some caudal fin rays, and 7 uppermost rays of pectoral fin, but absent from pelvic
and anal fin rays.
Numerous small papillae covering head andbody. Anterior nostril with low fleshy rim.
Posterior nostril opening upward behind low
lacrimal ridge, not visible laterally. Two distinct
sensory pores; 1st anterior to anterior nostril, 2nd
between anterior and posterior nostrils. Undersideof dentary with 3 small sensory pores on each side

and a small pore behind nodular portion of lower
jaw on each side. No scales on surface of head,
including opercle, interorbital space and occipital
pit. Body covered with small cycloid scales, notextending onto fins. No scales on ventral surface
of body or pectoral fin base.
Mouth oblique, forming an angle of about 40
to horizontal axis of head and body. Posterior
margin of maxilla not reaching vertical level ofanterior margin of orbit. Lateral surface of maxilla
smooth with no ridges. Lower jaw with thickened
symphysial portion fitting into shallow median
depression of upper jaw when mouth fully closed.
Width of symphysial gap separating premaxillaryteeth bands approximately equal to width of eachband. Upper and lower jaws with a band of villiform teeth, bands narrowing posteriorly; width oftooth band of upper jaw approximately equal tothat of lower jaw; most teeth of upper jaw approximately same length as teeth of lower jaw. Patch ofvilliform teeth on each side of vomer. No teeth onpalatine.
Dorsal profile of snout curved sinuously, initially convex, then deeply concave. Nasal spine
simple, directed dorsoposteriorly, its length approx-

Luzon I.

15°

10°Palawan I.
Mindanao I.

Kalimantan

5°

120°

125°

Fig. 4. Currently known capture localities of Hipposcorpaena
filamentosa.

216

Zoological Studies 44(2): 210-218 (2005)

imately equal to anterior nostril diameter. Posterior
margin of ascending process of premaxilla notreaching vertical level of posterior nostril. A distinct ridge projecting from lateral surface of frontal
located about midway between nasal spine andpreocular spine base. Interorbital ridges present,
beginning level with supraocular spine and endingat base of postocular spine. Interorbital spacedeep, forming V-shape in anterior view; about 1/2of orbit extending above dorsal profile of head.
Preocular spine simple, directed upward, tip
extending slightly beyond a horizontal line throughupper margin of pupil in lateral view. Supraocularspine simple, located considerably anterior to vertical midline of eye. Postocular spines simple, triangular in lateral view. Tympanic spine simple,
sharp, directed upward. No coronal or extra
spines. Occipital pit shallow with a distinct transverse ridge in front of occipital pit, curved posteriorly in dorsal view. Parietal and nuchal spines welldeveloped, both spines joined at base. Sphenotic
with 4 small spines. Postorbital with 2 small
spines, smaller than sphenotic spines. Pterotic
spine simple, small, pointed with narrow base,located just above uppermost end of preopercularridge. Posttemporal spine simple, pointed, small,directed dorsoposteriorly; no upper posttemporalspine. Supracleithral spines simple, pointed.
Lateral surface of lacrimal with 5 low ridges
radiating from center, but lacking spines; uppermost end of upwardly directed ridge with a bumpdirectly below anterior nostril; anterior end of forward ridge and lower end of downward ridge notprojecting over upper lip. Suborbital ridge very
low, with 3 spines; 1st spine located about midway
between front of upper lip and anterior margin oforbit; 2nd and 3rd spines adjoining, located below
posterior part of orbit. Very broad space between
ventral margin of orbit and suborbital ridge.
Suborbital pit shallow, front rimmed by an oblique
low lacrimal ridge. Preopercle with 3 blunt spines;
uppermost spine largest, with a low median ridge;
2nd spine with a low median ridge; 3rd spine without median ridge. No supplemental preopercularspine. Upper and lower opercular spines simple
with a median ridge; lower spine almost horizontal.
Origin of 1st dorsal fin spine above posttemporal spine base. Posterior margin of opercularmembrane and upper end of pectoral fin baseextending beyond vertical from base of 3rd dorsal
fin spine. Posterior tip of longest pectoral fin ray
extending well beyond vertical from posterior endof anal fin base. Origin of pelvic fin anterior tobase of pectoral fin; posterior tip of depressed

pelvic fin just reaching anus. Origin of 1st anal fin
spine below origin of last dorsal fin spine.
Color when fresh: See Fig. 1.
Color of preserved specimens: Based on
KPM-NI 13005, 35.2 mm SL. Snout between frontof upper lip and an oblique line from just below
orbit to lacrimal, and tentacles on lacrimal andlower preopercle white; underside of mandible andlower preopercle and opercle with melanophores;
remainder of head translucent white. Lateral surface of body yellowish with 2 almost vertical faintbrown bands (reddish in fresh specimen, see Fig.
1). Anteroventral surface of body, including area
between pelvic fin bases, blackish. Spinous portion of dorsal fin transparent (formerly white on
membrane between 1st and 2nd spines; red bandshown in Fig. 1 lost) with an oblique white marginal
band and a poorly defined small black spot basally
between 5th and 6th spines. Soft-rayed portion of
dorsal fin translucent. Pectoral fin base blackishwith a white blotch, larger than orbit diameter.
Pectoral fin membranes transparent with scatteredmelanophores in upper part. Pelvic and anal finmembranes black. Caudal fin transparent withblack posterior and ventral margins, and a large
back spot, approximately 1.5 times orbit diameter,
basally between 9th and 12th rays. Color of
USNM 168183 specimen (31.1 mm SL) had faded
to an entirely brown body, but 3 large spots on thelower basal caudal fin remained obvious.
Distribution: Currently known only from thePhilippines (Fig. 4).
Remarks: Hipposcorpaena filamentosa wasoriginally described by Fowler (1938) from a single
specimen (USNM 98819) from the Philippines.
Eschmeyer et al. (1973) corrected some of the,details given in the Fowler s original description
and figure, after examining the holotype, as
follows:“Fowler (1938, p. 73) gives a dorsal fin
count of XI + 10, but this should have been XII +91/2; he lists anal rays as 9, but they total 81/2 andseem to be III + 51/2...The rays near the lower endof the pectoral fin are the longest, and the 5th fromthe bottom extends past the posterior base of the,anal fin (not as in Fowler s figure 31). The verticalscale rows were given by Fowler as 30; althoughmany scales are missing, the scale rows probably
number about 35-40.”
Our examination of the newly collected specimen (KPM-NI 13005, 35.2 mm SL; Fig. 1) showed,
it to be consistent with Fowler s original description
and figure (and the corrections by Eschmeyer etal. 1973), with the exception of the anal fin ray(see“Remarks”of the genus account) and longitu-

Motomura and Senou -- Validity of Hipposcorpaena

dinal scale row (= vertical scale row) numbers, atentacle on the upper margin of the orbit, and black
markings on the lower caudal fin. Although counting the longitudinal scale rows was difficult owing
to their irregularity and the indistinct scale contours, the KPM-NI 13005 specimen had ca. 54
scale rows, a much higher number than previously
reported: 30 given by Fowler (1938), about 35~40
by Eschmeyer et al. (1973), and 30~45 by Poss,(1999). The holotype (according to Fowler s original figure) had a large tentacle on the upper margin of the orbit, whose length was greater than theorbit diameter. The other historical specimen(USNM 168183, 31.1 mm SL, examined in thisstudy) had a similar, but smaller tentacle, shorter
than the orbit diameter. Such a tentacle wasabsent from the KPM-NI 13005 specimen (seeFigs. 1, 2), indicating that the presence or absenceof a tentacle on the orbit may vary individually.
Figure 1 shows a distinct black spot on the lower
part of the caudal fin. However, the holotype
apparently had 4 spots on the lower part of thecaudal fin (from Fowler 1938: fig. 31), and the
USNM 168183 specimen had at least 3 blackspots (the posterior 1/2 of the caudal fin was broken). A related species, Rhinopias frondosa, variably has 1 or 2 black spots on the soft-rayed portion of the dorsal fin. Thus, we concluded that avariable number of black spots on the caudal fin in
H. filamentosa also represents individual variation.
Eschmeyer et al. (1973) believed that H. filamentosa was known only from 2“juvenile”specimens (29.4 and 31.1 mm SL). Dissection of theabdomen on the right side of the KPM-NI 13005
specimen (35.2 mm SL) of H. filamentosa showed
it to have an expanded gonad, full of relatively
large-sized ova, indicating that H. filamentosa is asmall species, and the other known specimens arepresumably also subadults or adults.
Eschmeyer et al. (1973) discussed the shedding of the“skin”in the genus Rhinopias, including R. aphanes, R. argoliba Eschmeyer, Hirosaki
and Abe, R. frondosa, and R. xenops. They
reported that the“skin”was best termed a cuticle,
being an epidermal product on the basis of a histological analysis of the shed layer by R. Krejsa. We
also found a cuticle in the process of shedding on
the under surface of the body in the KPM-NI 13005
specimen of H. filamentosa.
Hipposcorpaena is a monotypic genus; comparisons with other related genera are given inremarks under the genus account.
Acknowledgments: We are especially grateful to217

K. Ishigaki (Blue Corner Japan, Izunagaoka,
Japan) for providing the specimen of H. filamentosa. We are also grateful to the following persons
and institutions for specimen loans and providing
opportunities to examine material: J. Maclaine,(BMNH), J. E. Randall, L. O Hara, and A.
Suzumoto (BPBM), P. A. Gerard (MZUVN), and J.
Williams (USNM). We also thank G. S. Hardy(Ngunguru, New Zealand) for his valuable comments on the initial manuscript, Y. Motomura(Chatswood, Australia) for her assistance, and M.
McGrouther, T. Trnski, J. M. Leis, and other staff ofthe Fish Section, Australian Museum, for their continued assistance. Thanks are due to W. N.
Eschmeyer (CAS) who gave the financial support
to the 1st author to examine the type material
deposited in museums in Europe. This study was
supported in part by a postdoctoral fellowshipgrant awarded to the 1st author by the Japan
Society for the Promotion of Science for Research
Abroad (Tokyo, Japan).

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