Hymenocephalus torvus Smith & Radcliffe 1912
Creators: name: Schwarzhans, Werner
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Actinopterygii
Gadiformes
Macrouridae
Hymenocephalus
Hymenocephalus torvus

description: 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.   
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.
description: Published as part of Schwarzhans, Werner, 2014, Head and otolith morphology of the genera Hymenocephalus, Hymenogadus and Spicomacrurus (Macrouridae), with the description of three new species, pp. 1-73 in Zootaxa 3888 (1) on pages 61-62, DOI: 10.11646/zootaxa.3888.1.1, http://zenodo.org/record/10086415