Actinopteri (ray-finned fishes) > Anguilliformes
(Eels and morays) > Protanguillidae
Etymology: Protanguilla: Name from the Greek 'protos' meaning first, and Latin 'anguilla' for eel; referring to the early divergence of the genus among anguilliforms.; palau: Named for its type locality; noun in apposition (Ref. 87802).
Environment: milieu / climate zone / depth range / distribution range
Marine; reef-associated; depth range 35 - ? m (Ref. 87802). Tropical; 9°N - 6°N, 134°E - 135°E
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).
Size / Weight / Age
Maturity: Lm ?  range ? - ? cm
Max length : 17.6 cm TL (female)
Morphology | Morphometrics
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).
Cave species (Ref. 87802).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Johnson, G.D., H. Ida, J. Sakaue, T. Sado, T. Asahida and M. Miya, 2012. A 'living fossil' eel (Anguilliformes: Protanguillidae, fam. nov.) from an undersea cave in Palau. Proc. Royal Soc. B 279(1730):934-943. (Ref. 87802)
IUCN Red List Status (Ref. 125652)
Threat to humans
Common namesSynonymsMetabolismPredatorsEcotoxicologyReproductionMaturitySpawningSpawning aggregationFecundityEggsEgg development
ReferencesAquacultureAquaculture profileStrainsGeneticsAllele frequenciesHeritabilityDiseasesProcessingNutrientsMass conversion
Estimates based on models
Phylogenetic diversity index (Ref. 82804
= 1.5000 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00102 (0.00046 - 0.00225), b=3.06 (2.88 - 3.24), in cm total length, based on all LWR estimates for this body shape (Ref. 93245
Trophic level (Ref. 69278
): 3.5 ±0.6 se; based on size and trophs of closest relatives
Fishing Vulnerability (Ref. 59153
): Low vulnerability (10 of 100).