Head and otolith morphology of the genera Hymenocephalus, Hymenogadus and Spicomacrurus (Macrouridae), with the description of three new species
Author
Schwarzhans, Werner
text
Zootaxa
2014
2014-11-28
3888
1
1
73
journal article
10.11646/zootaxa.3888.1.1
1175-5326
10086415
1B437AE1-CF28-4C1B-95B6-C31A295905A0
Hymenocephalus torvus
Smith & Radcliffe, 1912
Figs. 33A–G
,
37
Hymenocephalus torvus
Smith & Radcliffe, 1912: 110
(
type
locality: off Jolo,
06°00’N
,
120°45’E
; location corrected by
Jordan
&
Gilbert, 1920
).
Hymenocephalus torvus
:
Iwamoto & McCosker, 2014: 281
.
Hymenocephalus striatissimus torvus
:
Jordan
&
Gilbert, 1920: 530
.
Material examined.
15 specimens
;
2 specimens
(otoliths only)
USNM 148995
,
13°47’N
,
121°35’E
,
347 m
;
5 specimens
USNM 149032
,
96
+ –
143 mm
TL,
Albatross
Philippines
Expedition
(no further details)
;
1 specimen
USNM
149465, 160 mm
TL,
08°37’N
,
124°36’E
,
402 m
;
1 specimen
USNM
149468, 162 mm
TL,
08°35’N
,
124°36’E
,
366 m
;
1 specimen
(otolith only)
USNM 149471
,
13°32’N
,
121°01’E
,
446 m
;
2 specimens
ZMUC
unregistered
09.03.1914
, 117–
136 mm
TL,
07°25’N
,
123°14’E
.
Diagnosis.
Pelvic fin rays 7 (rarely 8 on one side); pectoral fin rays 12–14; gill rakers 19–22. Barbel short, 10–15% HL. Orbit 34–40% HL. Snout short, only slightly protruding, 15–20% HL. Ventral striae extending to periproct. Infraorbital supporter long, 80–90% OD. Otolith compressed, OL:OH = 0.8–0.9; colliculi fused; pseudocolliculum long, TCL:PCL = 1.35–1.5.
Comparison.
For differences see discussion to
H. aeger
and
H. striatissimus
.
Description.
Head morphology (n = 2) (
Fig. 33A–B
): Snout short, slightly projecting, 15–20% HL, orbit diameter large, 34–40% HL, interorbital width 60–70% HW. Barbel short, 10–15% HL, not or just reaching vertical through anterior rim of orbit. Head canals well developed, infraorbital width 12–15% HL, supraorbital canal with 5 segments, width 13–15% HL, supratemporal canal above segment 4 of supraorbital canal, preopercular canal width 12–16% HL, postorbital-preopercular interspace 4–7% HL. Infranasal supporter moderately large; infraorbital supporter long, extended below almost entire length of orbit, 80–90% OD; preopercular supporter moderately long, 5–8% HL, with straight rear margin.
FIGURE 33.
Hymenocephalus torvus
: A–B—USNM 149465, A—Lateral view of head, B—Dorsal view of head. C–G—MNHN 2005-0928, otoliths, C, D, F—Inner faces, E—Anterior view, G—Ventral view.
Otolith morphology (n = 10) (
Fig. 33D–G
). Otolith large; OL:OH = 0.8–0.9; OH:OT = 3.5. Dorsal rim with very large, broad, undulating or crenulated predorsal lobe, distally marked by indentation; posterior tip rounded, positioned at about level of sulcus termination; ventral rim deep, regularly curved, smooth, deepest anterior of the middle; anterior rim high, nearly vertical. Inner face slightly convex, with median sulcus. Colliculi completely fused, terminating far from anterior and posterior tips of otolith; pseudocolliculum very long. TCL:PCL = 1.4–1. 5. Dorsal depression moderately large, moderately indistinct; ventral furrow distinct, close to ventral rim.
Discussion
. I follow
Iwamoto and McCosker’s (2014)
rationale in regarding
H. torvus
as a species separate from
H. striatissimus
, with snout profile and pectoral fin counts probably adding further characters for distinction, while otolith morphology does not.
Distribution
(
Fig. 37
). The geographic distribution of
H. torvus
appears to be restricted to the
Philippines
.