Hymenocephalus punt, Schwarzhans, 2014

Schwarzhans, Werner, 2014, Head and otolith morphology of the genera Hymenocephalus, Hymenogadus and Spicomacrurus (Macrouridae), with the description of three new species, Zootaxa 3888 (1), pp. 1-73 : 52-55

Hymenocephalus punt n.sp.

Figs. 1D–F , 25A–B , 26A–K , 27

Material examined. (30 specimens, 87–168 mm TL.) Holotype ZMMGU P-23599, 106+ mm TL, off western Socotra, Yemen, 12°18’ to 12°14’N, 53°09’ to 53°06’E, 375–380 m, bottom shrimp trawl, Vityaz cruise 17, station 2560, 27 October 1988 ; Paratypes: ZMMGU P-23600 (ex IORAS 00222 ), 5 specimens, 99–140 mm, same data as holotype (further 16 specimens not studied) . ZMMGU P-23601 (ex IORAS 00223 ), 6 specimens, 87–146 mm TL (further 3 specimens not studied), 12°20’ to 12°13’N, 53°11’ to 53°06’E, 384–390 m, bottom trawl, Vityaz cruise 17, station 2566, 28 October 1988 . ZMMGU P-23602 (ex IORAS 00229 ), 1 specimen, 125 mm TL (further 1 specimen not studied), 12°19’ to 12°13’N, 53°09’ to 53°05’E, 395–420 m, bottom shrimp trawl, Vityaz cruise 17, station 2830, 16 January 1989 . ZMMGU P-23603, 2 specimens, 155–168 mm TL, 16°14’N, 52°41’E, 490–530 m, Dm. Stefanov cruise 3, trawl 143, 15 February 1989 . USNM 301271 , 3 specimens, 81+ – 130 mm TL, 12°01’N, 51°16’E, 375–393 m, bottom trawl, Beinta cruise 20, haul 18, 12 March 1987 , G. and J. Small. BMNH 1939.5.24.691–702, 12 specimens, 13°41' to 13°13' N, 46°14' to 46°10'E, 441 m, Murray Expedition station 35, 16 October 1933 .

Diagnosis. Pelvic fin rays 10–11; pectoral (13) 14–15; gill rakers 20–24. Barbel moderately long 11–15% HL, reaching vertical through anterior rim of orbit. Orbit 28–30% HL. Snout pointed, protruding, 17.5–20% HL. Ventral striae extending to about ⅓ to ½ the distance from pelvic fin bases to periproct. Otolith moderately compressed (OL:OH = 1.0–1.05); colliculi separated, small; pseudocolliculum small (TCL:PCL = 1.9–2.2).

Comparison. Hymenocephalus punt is related to H. heterolepis from which it differs in a number of rather subtle characters as follows: pectoral fin rays 14–16, rarely 13 seen on one side only (vs 11–13), luminescent striae reaching about one third to half the distance from ventral fin bases to periproct (vs two thirds the distance to nearly reaching the periproct), barbel reaching vertical through anterior rim of orbit / 11–15% HL (vs not reaching vertical through anterior rim of orbit / 6–9% HL), OL:OH = 1.0–1.1 (vs 0.9–0.95) and TCL:PCL = 1.9–2.2 (vs 1.5–1.7).

Description. Counts (from 28 specimens): 1D. II,8 (II,8–10); P. 14 (14–15, occasionally 13 on one side); V. 11 (10–11); first gill raker inner side 22 (20–24); second gill raker outer side 23 (20–24).

Measurements (from holotype and two best-preserved paratypes): head length 32.8–33.7 mm, about 20% TL (from PT ZMMGU P- 23603, 168 mm TL); head height 72–76% HL; head width 52% HL (holotype only); barbel 11–15% HL; snout 17.5–20% HL; orbit 28–30% HL; postorbital 50–54%HL; interorbital 32% HL / 61% HW (holotype only); upper jaw length 47–49% HL; pre-anal about 150% HL; pre-dorsal to 1D about 90–100% HL; pre-dorsal to 2D about 180–190% HL; distance base 1D to 2D about 90–100% HL; 1st dorsal fin length about 70% HL, the first fin ray being slightly longer than the subsequent ones; pectoral fin length 70–75% HL, the first fin ray being markedly longer than the subsequent ones; ventral fin length, 1 st ray 95% HL, 2 nd ray 50–55% HL; supraorbital canal width 10–13% HL; infraorbital width 9.5–12% HL; minimal infraorbital canal width 6.0–7.5% HL.

The following description is based on the holotype. Body moderately slender with large head, highest and widest at rear part of head just behind orbit, tapering rather regularly behind first dorsal into the usual whip-like tail. Origin of pectoral and ventral fins about on same vertical, origin of first dorsal more anteriorly positioned. First ray of ventral nearly twice the length of subsequent rays; first rays of first dorsal and pectoral also somewhat longer than subsequent rays. Second dorsal rudimentary; anal well developed.

Teeth all small in narrow bands in both jaws.

Luminescent tissue (striae) dark, dominantly black with few silver stripes, extending as a narrow band along both sides of isthmus below gill covers, reaching to bases of pectoral fins and behind ventral fin bases, where they join along medial line, and extend to about 30–50% of the distance from ventral fin bases to periproct region. Gular region dark, with some black lines. Anterior lens of ventral luminescent organ small; posterior lens before periproct about two times larger, tear-drop shaped, anteriorly with triangular stretch of dark tissue and broad dark tissue to sides of lens as well.

Axial skeleton (based on radiographs). Number of precaudal vertebrae 10; vertebrae 1–3 much shorter than subsequent vertebrae. Neural spines of vertebrae 1 and 2 about twice as long as vertebra 3, forwardly inclined, neural spine 1 stronger than 2; neural spines 3 to 8 depressed, spines 3 to 7 with blunt tips; neural spines 3 to 6 short and of equal length, spines 7 to 8 increasing in length. Bases of neural spines 4 to 8 enlarged. Parapophyses on vertebrae 6 to 10. Pleural ribs on vertebrae 5 to 8 or 9. First fin ray of 1D supported by two pterygiophores, both inserted behind neural spine 2. Last pterygiophore of 1D inserted behind neural spine 8. First pterygiophore of 2D above vertebra 17 to 18. First pterygiophore of anal fin not prolonged, inserted in front of first haemal spine on first caudal vertebrae (11).

Head morphology (n = 4): Head massive, with pointed anterior profile and snout protruding well beyond mouth. Bones moderately thin and fragile; eyes moderately large; barbel moderately long, reaching vertical through anterior rim of orbit. Head canals well developed, covered with very thin, mostly fragmented integument. Infraorbital width 10–15%HL, supraorbital canal with 5–6 segments, width 7–12% HL, supratemporal canal narrow, above segment 4 of supraorbital canal, preopercular canal width 10–12% HL, postorbital-preopercular interspace 7–10% HL. Neuromasts exceptionally clearly visible in several specimens because of overall dusty dark pigmentation and good overall preservation ( Fig. 1D–F ). Infranasal supporter well developed; infraorbital supporter expanded only below rear part of orbit, 40–60% OD; preopercular supporter moderately long (4–6% HL), with straight rear margin; mandibular hook distinct.

Otolith morphology (n = 10): Otolith high bodied, slightly longer than high; OL:OH = 1.0–1.1; OL:OT about 3.5. Predorsal lobe massive, marked posteriorly by an incision located slightly behind middle of otolith. Anterior rim irregularly curved, high; posterior tip rounded. Ventral rim moderately deep and regularly curved, deepest slightly anterior of middle. Inner face slightly convex along horizontal axis, with narrow, median to slightly inframedian sulcus. Ostial and caudal colliculi small, well separated (nearly joined in one specimen), of nearly equal size; pseudocolliculum moderately enlarged. CCL:OCL = 1.0–1.2; TCL:PCL = 1.9–2.2. Dorsal depression indistinct; ventral furrow distinct, moderately close to ventral rim.

Coloration (in alcohol): Medium to dark brown; opercle, premaxilla and ventral region from tip of mandible to periproct particularly dark; numerous small melanophores on preopercle, upper lip, anterior rim of nape and along sides of nasal flap; first dorsal, ventral and pectoral fins with small melanophores, pectoral fin with dark area on central part, when well preserved; melanophores at bases of second dorsal and anal fin rays; body above median line and behind opercle darker brown than below; entire body behind head with irregularly distributed star-like large melanophores.

Distribution. Probably endemic off the shores of northern Somalia, Yemen and southern Oman.

Etymology. The new species is named after the mythic kingdom of Punt, thought to have been historically located in northern Somalia. The name is used as a noun in apposition.

Figures

FIGURE 1. Head morphology and sensory system of Hymenocephalus: A—Head morphology in lateral view. B—Head morphology in dorsal view. C—Head morphology in ventral view.

FIGURE 25. Hymenocephalus punt: A—Paratype, ZMMGU-P 23600, TL 140 mm (photo M. Krag). B—Holotype ZMMGU- P 23599, TL 106+ mm (photo M. Krag).

FIGURE 26. Hymenocephalus punt: A–B—Holotype, ZMMGU-P 23599, TL 106+ mm, A—Lateral view of head, B—Dorsal view of head. C—Paratype, ZMMGU-P 23602, TL 125+ mm, lateral view of head. D—Paratype, ZMMGU-P 23603, TL 168 mm, lateral view of head. E–F—Paratype, ZMMGU-P 23600, TL 99+ mm, E—Ventral view of head and trunk, F—detail view of posterior lens of ventral luminescent organ. G–K—Otoliths, G—Anterior view, H, J, K—inner faces, I—Ventral view, G–I—Paratype, ZMMGU-P 23600, TL 140 mm, J—Paratype, USNM 301271, TL 130 mm, K—Paratype ZMMGU-P 23600, TL 99+mm.

FIGURE 27. Geographical distribution of Hymenocephalus antraeus, H. hachijoensis, H. heterolepis and H. punt.