Entosphenus lethophagus (Hubbs, 1971)
Pit-Klamath brook lamprey
Entosphenus lethophagus
photo by FAO

Family:  Petromyzontidae (Northern lampreys), subfamily: Lampetrinae
Max. size:  22 cm TL (male/unsexed)
Environment:  demersal; freshwater, non-migratory
Distribution:  North America: Klamath River in south central Oregon (rare) and Pit River in northeastern California, USA.
Diagnosis:  Dorsal spines (total): 0-0; Anal spines: 0-0. Adults: 12.4-18.4 cm TL. Adult body proportions, as percentage of TL (based on ten specimens 12.6-18.4 cm TL): prebranchial length, 8.2-13.3; branchial length, 8.4-10.8; trunk length, 43.4-51.6; tail length, 28.8-35.3; eye length, 1.6-3.2; disc length, 4.1-6.1; urogenital papilla length, 16.0 (percentage of branchial length in a spawning male measuring 12.9 cm TL); trunk myomeres, 58-73. Adult dentition: supraoral lamina, 2-3 unicuspid teeth, usually 3; infraoral lamina, 5-7 unicuspid teeth; 4 endolaterals on each side; endolateral formula, typically 2-2-2-2 or 2-3-3-2, the first and fourth endolaterals may also rarely be unicuspid; 2-3 rows of anterials; first row of anterials, 1 or 5 unicuspid teeth; exolaterals absent; 1 row of posterials with 10-17 teeth, of which 0-12 are bicuspid and the rest unicuspid; transverse lingual lamina, 15-20 unicuspid teeth, the median one slightly enlarged; longitudinal lingual laminae each with undetermined number of unicuspid teeth. Velar tentacles in adults, 5-12, with tubercles; median tentacle shorter than the lateral ones immediately next to it; body coloration (preserved), ventral aspect whitish; oral papillae, 5-26 (Ref. 89241).
Biology:  Inhabits riffles and runs of clear streams. Ammocoetes larvae occur near weed beds and sand bars. Non-parasitic (Ref. 5723). Freshwater; adults from Crooked Creek, Oregon are sexually mature in mid-March (Ref. 89241).
IUCN Red List Status: Least Concern (LC); Date assessed: 22 February 2012 Ref. (130435)
Threat to humans:  harmless


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