Morphology Data of Lethenteron alaskense
Identification keys
Main Ref. Mecklenburg, C.W., T.A. Mecklenburg and L.K. Thorsteinson, 2002
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 eel-like
Cross section
Dorsal head profile
Type of eyes
Type of mouth/snout
Position of mouth
Type of scales

Adult preserved specimens gray-brown dorsally, white ventrally, with a dark blotch on 2nd dorsal fin; tail dark. Teeth on disk blunt and weakly cornified. Tongue teeth poorly developed and blunt. Typical length 12-17 cm TL (Ref. 43939). Trunk myomeres 66-72 (Ref. 43938, 89241). Other adult diagnostic features: 12.2-18.8 cm TL. Body proportions, as percentage of TL (based on 68 specimens measuring 12.2-18.8 cm TL): prebranchial length, 9.3-14.9; branchial length, 8.7?11.6; trunk length, 45.4-53.5; tail length, 25.7-33.5; eye length, 1.7-3.2; disc length, 3.8-7.3. Urogenital papilla length, as a percentage of branchial length, in a 14.1 cm TL spawning male, 26.9. The shape of the second dorsal fin in spawning males is arch-like and in females triangular. Dentition: supraoral lamina, 2 unicuspid teeth (1 of 34 specimens had 2 additional small unicuspid teeth on the bridge); infraoral lamina, 6-11 teeth, the lateralmost one on each side unicuspid or bicuspid and the internal ones unicuspid; 3 endolaterals on each side; endolateral formula, 2-2-2; 3 rows of anterials; first row of anterials, 3-5 unicuspid teeth; total number of anterials, 23-38 unicuspid teeth; exolaterals absent or one or two unicuspid exolaterals present in each lateral field, exceptionally, one complete row of exolaterals on each side; single row of posterials, 17-24 unicuspid teeth; transverse lingual lamina, 9-15 unicuspid teeth, the median one greatly enlarged; longitudinal lingual laminae each with 6-13 unicuspid teeth. Velar tentacles, 5-7, with tubercles and with the single median tentacle shorter than the lateral tentacles immediately next to it. Body coloration (preserved) in mature adults is gray brown on the upper surface and flanks and whitish on the lower surface. Lateral line neuromasts unpigmented. Gular region unpigmented (2 of 64 specimens had weak pigmentation). Second dorsal fin with a dark blotch near the apex (4 of 64 specimens did not have a blotch). Extent of caudal fin pigmentation, 1% to <25% (17% of specimens), 25% to <75% (36%) or, 75% or more (46%). Caudal fin shape, spade-like. Oral papillae, 18 (Ref. 89241).

Ease of Identification

Meristic characteristics of Lethenteron alaskense

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


Dorsal fin(s)

Fins number 2
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 )
Entered by Capuli, Estelita Emily
Modified by Hilomen, Teresa
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