Hymenocephalus longipes Smith & Radcliffe, 1912
Hymenocephalus longipes
photo by MNHN

Family:  Macrouridae (Grenadiers or rattails)
Max. size:  15.5 cm TL (male/unsexed)
Environment:  benthopelagic; marine; depth range 274 - 2081 m
Distribution:  Western Central Pacific: Philippines.
Diagnosis:  Distinguished by the following characters: pelvic fin rays 8; pectoral fin rays 13-15; black-colored tips of pelvic fins; barely projecting snout; head bones are rather firm; no barbel; orbit diameter 28-33% HL; interorbital width 40-50% HW (head width); gill rakers 19-21; ventral striae reaching close to periproct; otholith length to height (OL:OH) is 1.1-1.25; total colliculum length to pseudocolliculum length (TCL:PCL) is 1.7-2.1 (Ref. 98298). Description: head with rounded, soft-tipped and non-projecting snout, its length 15% HL, orbit diameter 28-33% HL, interorbital width 40-50% HW; head canals are well developed, infraorbital width 10-12% HL, supraorbital canal with 6 segments, width 5-10% HL, supratemporal canal indistinct, preopercular canal width 7-12% HL, postorbital-preopercular interspace 11-13% HL; small infranasal supporter; infraorbital supporter moderately widened throughout length below orbit, expanding beyond rear part of orbit, 80-100% OD; broad preopercular supporter, also blunt, with straight rear margin short (3-5% HL). Otolith morphology: otolith moderately high bodied; OL:OH = 1.1-1.25; OL:OT about 4; large predorsal lobe with pointed tip, triangular in shape, rather gently inclining towards rear part of otolith with some undulation; irregular anterior rim, also broadly rounded to blunt, its posterior tip moderately pointed; deep ventral rim, smooth and regularly curved, deepest anterior of middle; inner face very slightly convex along horizontal axis, with median sulcus; ostial and caudal colliculi moderately large, narrowly placed at collum, terminating at considerable distance from anterior and posterior tips of otolith; pseudocolliculum moderately enlarged. caudal colliculum length to ostial colliculum length (CCL:OCL), 0.9-1.0; TCL:PCL = 1.7-2.1; dorsal depression wide; ventral furrow thin, close to ventral rim (Ref. 98298).
Biology: 
IUCN Red List Status: Not Evaluated (N.E.) Ref. (130435)
Threat to humans:  harmless


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