Threatened fishes of the world: Ophisternon infernale (Hubbs, 1938) (Synbranchidae)

Abstract

Common name: Anguila ciega, anguila ciega yucateca (S). Conservation status: Endangered (IUCN). Identification: Total lack of external eyes and melanin pigment. Muzzle spatulate. Up to 325 mm SL. Lack of scales. Head long and bulb shaped with sensitive pores. Caudal region 37–54% longer than in other synbranchids (drawing by Rhian Hicks, 325 mm TL). Distribution: Cenotes and groundwater on the Yucatán Peninsula, Mexico (20–21°N, 88–90°W), including anchialine caves on the Caribbean coast. This species is sympatric in some areas with Ogilbia pearsei (Bythitidae) and Rhamdia guatemalensis (Pimelodidae) (Chumba-Segura 1984). Abundance: Very few specimens have been observed (maximum two at the same time) in very few localities. Underwater exploration should increase the number of recorded sites. It is of note that several locals in rural areas have seen Ogilbia pearsei but not Ophisternon infernale. Habitat and ecology: Builds mucus-lined burrows in organic rich sediments within the freshwater part of the aquifer. Has been observed under stones in muddy bottoms in the shallow parts of cave cenotes, and at 24 m in depth. The principle source of f energy in this environment is bat and swallow guano. Ophisternon infernale. feeds on the troglobitic shrimp Creaseria morleyi, tolerates low oxygen levels and is able to breathe atmospheric oxygen. Reproduction: Reported to be oviparous. Threats: The main threat is from water pollution, principally faecal coliforms and excess nitrate (Cruickshank et al. 1980).