Morphology Data of Hymenocephalus nascens
Identification keys
Abnormalities
Main Ref. McMillan, P. and T. Iwamoto, 2014
Appearance refers to
Bones in OsteoBase

Sex attributes

Specialized organs
Different appearance
Different colors
Remarks

Descriptive characteristics of juvenile and adult

Striking features
Body shape lateral elongated
Cross section
Dorsal head profile
Type of eyes
Type of mouth/snout
Position of mouth
Type of scales
Diagnosis

This species is distinguished by the following characters: pelvic rays usually 12-14 (elsewhere 11-13); total gill-rakers first arch (outer/inner) 17-22/23-28, second arch 22-28/22-26; no chin barbel; snout length 22-31% HL; orbit diameter 29-40% HL; suborbital width 10-14%HL, interorbital width 24-29%HL; most of the orbit, upper surface of snout, sides of head and trunk silvery or pale, ventral aspects of heed and trunk black; a prominent midlateral stripe of silvery (when fresh) or brownish (preserved) pigment running along trunk and tail (Ref. 97189). Additional distinguishing characteristics: pectoral fin rays 13-16; projecting snout, 20-26% HL; infraorbital width 11-16% HL; moderately long preopercular supporter, with obtuse angle at rear margin, 4-9% HL; ventral striae reaching to ½ distance from pelvic fin bases to periproct; otolith has moderately high predorsal lobe, with colliculi separated, closely placed across collum with a tendency to joining in large individuals, terminating at some distance from anterior and posterior rims of otolith; otolith length to height (OL:OH), 1.1-1.2; total colliculum length to pseudocolliculum length (TCL:PCL), 1.8-2.4 (Ref. 98298).

Ease of Identification

Meristic characteristics of Hymenocephalus nascens

Lateral Lines Interrupted: No
Scales on lateral line
Pored lateral line scales
Scales in lateral series
Scale rows above lateral line
Scale rows below lateral line
Scales around caudal peduncle
Barbels
Gill clefts (sharks/rays only)
Gill rakers
on lower limb
on upper limb
total
Vertebrae
preanal
total

Fins

Dorsal fin(s)

Attributes
Fins number 2
Finlets No. Dorsal   0 - 0
Ventral  0 - 0
Spines total 2 - 2
Soft-rays total
Adipose fin absent

Caudal fin

Attributes

Anal fin(s)

Fins number 1
Spines total
Soft-rays total

Paired fins

Pectoral Attributes  
Spines     0
Soft-rays   14 - 16
Pelvics Attributes  
Position    
Spines     0
Soft-rays   12 - 13
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