Protanguilla palau Johnson, Ida & Sakaue, 2012
Palauan primitive cave eel
Protanguilla palau
photo by Johnson, G.D.

Family:  Protanguillidae (Protoanguillids)
Max. size:  17.6 cm TL (female)
Environment:  reef-associated; marine; depth range - 35 m,
Distribution:  Western Pacific: Republic of Palau. Presently known from a western fringing reef of Ngemelis Island, in a reef cave at 35 m depth. As an elopomorph, it almost certainly has a leptocephalus larval form, and letptocephali (particularly those of anguilliforms) are known to have long planktonic durations (2-10 months). Accordingly, the authors believe that Protoanguilla probably has a considerably broader distribution than currently known, even though no leptocephali matching its unique meristic formula (fewer than 90 vertebrae, more than 170 dorsal fin and anal fin rays) have been identified in extensive worldwide larval fish collections. In any case, historically, the Protoanguilla lineage, estimated to have diverged ca 200Ma, must have been much more widely distributed, because the Palau-Kyushu Ridge formed only around 60-70 Ma (Ref. 87802).
Diagnosis:  Gill opening terminates as ovoid tube with low, fringed collar; pseudobranch present; knob-like, toothed gill rakers present; premaxilla present, autogenous; symplectic autogenous; metapterygoid present; anterior end of vomer with small, ovoid, autogenous toothplate; body relatively short, total vertebrae 87 or fewer (79–87, mean ¼ 83.3); hypurals 3 and 4 not fused to each other; pterosphenoid not excluded from posterior margin of orbit (Ref. 87802).
Biology:  Cave species (Ref. 87802).
IUCN Red List Status: Data deficient (DD); Date assessed: 21 November 2019 Ref. (124695)
Threat to humans:  harmless
Country info:   

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