Lucifuga (Stygicola) spelaeotes Cohen and Robins, 1970
|Lucifuga (Stygicola) spelaeotes: © Joe Dougherty|
Taxonomic Characterization: Chin barbell absent. Gill membranes separate. Ventral fins
each with a single ray, immediately adjacent to each other, originating well
behind the symphysis of the cleithra. Head partially naked, bearing prominent
canals with large chambers. Body compressed, tail section not greatly elongated,
snout depressed. Lateral line interrupted. Eyes poorly developed. Body
completely covered with small, imbricate scales. Total vertebrae 49 to 53.
Ecological Classification: Stygobitic
Size: Adult male sampled was 109 mm. Adult female sampled was 76.5 mm.
Number of Species in Genus: Six, all stygobitic except L. (S.) inopinata
Lucifuga: genus range
Species Range: Known from numerous inland and ocean blue holes in
Abaco, Andros, Grand Bahama, and New Providence.
Closest Related Species: From the same subgenus as Lucifuga (Stygicola) dentatus and Lucifuga (Stygicola) simile, both from Cuba and Lucifuga (Stygicola) inopinata from the Galapagos Islands.
Habitat: Anchialine and marine limestone caves
Ecology: This fish lives in anchialine caves (Iliffe, 1992) on several Bahamian Islands. Some of them (e.g. Mermaids Hole, Uncle Charlie's Blue Hole) are typical inland holes of the cenote type, circular openings between 30 and 250 m across and from 2 to 110 m depth. They contain freshwater from the surface down to a mixing zone at variable depths and below this full strength sea water (Smart, 1984). L. spelaeotes was collected in the freshwater zone of Uncle Charlie's Blue Hole (Farr and Palmer, 1984; Proudlove, 1984), together with the grapsid crab Sesarma angustipes. One individual from this site was placed in a dish of sea water and appeared quite happy so it is possible that migration is possible within the extensive sea water filled passages. Other populations are known from typical marine Blue Holes (see e.g. Farr and Palmer, 1984). These are sub horizontal passages, up to several km in length, which open beneath the sea and carry flows of inland freshwater. A third habitat type, deep fracture oriented chasms, is seen on Grand Bahama (Palmer, 1985; Cunliffe, 1985).
Life History: Live bearing; male genitalia well developed, lacking ossified parts.
Evolutionary Origins: Presumed to be related to deep-water species with depressed snouts, presently placed in Cataetyx and Diplacanthopoma. Similarities are seen in body and head shape, copulatory apparatus and ventral fin placement. This species cannot now consist of a panmictic population as its many populations are separated by impassible sea water barriers. The morphological similarity of the animals may be as a result of lack of divergence from a once widespread ancestor (when the sea levels were lower and the Bahamian banks were much larger) or they are morphospecies (Proudlove, in press).
Conservation Status: I (IUCN, 1994). VU - vulnerable (A1ce, B1+2bc, D2) (IUCN, 1996). Some of these criteria relate to a decline in area of occupancy and/or quality of habitat (A1c) and the effects of pollutants, pathogens etc. (A1e). Others relate to a continuing decline in other important habitat characteristics (B1+2bc). The D2 criterion is applied if the population is estimated as less than 1000, the area of occupancy is less than 100 km2, or the number of recorded locations is less than 5. If the population of this species on New Providence is considered alone these criteria seem reasonable as the island is small and heavily populated. If the other populations on Grand Bahama, Abaco, Andros, Long Island, and Berry Island are added these criteria cannot be supported. The habitats on the other islands are under much less pressure than those on New Providence and the area of occupancy is at least 30800 km2 (220 km x 140 km). Introduced species of fishes are a potential threat to all of the native fish fauna (Proudlove, in press).
Contributor: Graham Proudlove, University of Manchester, UK
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