Morphology Data of Etmopterus alphus
Identification keys
Main Ref. Ebert, D.A., N. Straube, R.W. Leslie and S. Weigmann, 2016
Appearance refers to
Bones in OsteoBase

Sex attributes

Specialized organs
Different appearance
Different colors

Descriptive characteristics of juvenile and adult

Striking features
Body shape lateral fusiform / normal
Cross section oval
Dorsal head profile
Type of eyes
Type of mouth/snout
Position of mouth
Type of scales placoid scales

This relatively small, slender species of linear-denticled Etmopterus can be separated from its closest congeners within the E. lucifer clade by a combination of characteristics: length of its anterior flank markings being much shorter than its posterior branch; black flank markings sharply demarcated by surrounding lighter to whitish lateral markings; prominent white spot on each cheek; a single white stripe extending the length of the midback; 2 parallel rows of prominent dark pores extending between pectoral and pelvic fins; its closest geographic congener E. sculptus has its anterior branch longer than its posterior branch, with a thinner posterior flank marking, 0.2-0.4% (vs. 0.6-0.9% TL in E. alphus), a higher spiral valve count 8-9 (vs. 5-7 in E. alphus); it differs from its closest morphological congener, the Australasian E. molleri by its shorter anterior (6.0-10.6% vs. 8.0-11.5% TL) and posterior (9.3-12.7% vs. 11.0-15.4% TL) flank-marking branches, biogeography and genetics (Ref. 112348).

Ease of Identification

Meristic characteristics of Etmopterus alphus

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
Gill clefts (sharks/rays only)
Gill rakers
on lower limb
on upper limb
preanal 60 - 63
total 84 - 90


Dorsal fin(s)

Fins number
Finlets No. Dorsal   
Spines total
Soft-rays total
Adipose fin

Caudal fin


Anal fin(s)

Fins number
Spines total
Soft-rays total

Paired fins

Pectoral Attributes  
Pelvics Attributes  
Main Ref. (e.g. 9948)
Glossary ( e.g. cephalopods )
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