Bermudacaris harti Anker & Iliffe, 2000
Bermudacaris harti: ovigerous female
Taxonomic Characterization: Bermudacaris harti is uniformly
white alpheid shrimp with considerable reduction in
corneal pigment, especially in females. It is unique among alpheids due to its
unenlarged and almost symmetrical 1st chelipeds which are carried extended and
elevated. The merus is slender, the chela slim with the cutting edges of both
fingers being unarmed and the dactylus situated in a ventral position. The males
possess an appendix masculina. The shape of the frontal margin is not emarginate
and the eyestalks are subconical with depigmented or reduced pigmented eyes. The
species has a small acute antennular carina and slender 3rd-5th pereiopods. The
ischium of the 5th leg has a small spine. The pleosomites are well-developed and
partially cover the eggs of the female. The 2nd maxilliped has a small
podobranch inserted near the base of the epipod and the last segment of the 3rd
maxilliped has many rows of thick setae on the ventral side. The female
eyestalks have almost no pigmentation while the males have a small black spot
(Anker & Iliffe, 2000).
Disposition of Specimens: Specimens were deposited in the National Museum of Natural History, Smithsonian Institution, Washington D.C. and in the Museum National d'Histoire Naturelle, Paris; ovigerous female holotype from Christie's Cave (USNM 250781).
Ecological Classification: Stygobitic
Size: Total body length of ovigerous female holotype 11.5 mm; total body length of 2 male paratypes ranged from 10-11 mm.
Number of Species in Genus: Two, of which B. harti is the only stygobitic species.
Species Range: Known only from Christie's, Tucker's Town, Bat and Green Bay Caves, Bermuda (Anker & Iliffe, 2000).
Closest Related Species: Bermudacaris australiensis, the second species of the genus, represents the first discovery of the genus in the Indo-Pacific (Anker & Komai, 2004). The unique specimen of Bermudacaris australiensis was collected from an apparently typical marine environment on the North-West Shelf off Western Australia. B. harti had been previously confused with Automate dolichognatha by Hart & Manning (1981). They are similar in the frontal region which has partly exposed parallel eyestalks. Other similarities include a reduced exopod on the 3rd maxilliped bearing spines on the superior margin of the last segment, an elongate 2nd pereiopod with similar proportions of carpal articles and no deep bifurcation on the external flagellum of the antennule. Bermudacaris differs from Automate in several important points, notably those concerning the first chelipeds and appendix masculina (Anker & Iliffe, 2000).
Habitat: Anchialine limestone caves
Ecology: Specimens were collected at depths ranging from 8-20 m. Salinity among the four caves ranged from 6.5-22.7 ppt at the surface and from 19.5-27.5 ppt at 1 m. Temperature ranged from 17.8-20.0 C at the surface increasing to 21.5 C at 21 m. The locations from which B. harti was collected are all quite isolated from the sea and are populated by a varied of other stygobitic crustaceans including the shrimps Barbouria cubensis, Parhippolyte sterreri and Typhlatya iliffei (Anker & Iliffe, 2000).
Life History: Collected specimens included 3 males and 2 ovigerous females. The presence of few large eggs on the female could be an indicator of low fecundity and abbreviated larval development.
Evolutionary Origins: B. harti could be derived from ancestors common to both itself and Automate or could represent a highly modified species of Automate. Marine ancestors of this stygobitic species probably entered anchialine caves from neighboring shallow, marine waters since all modern species of Automate are shallow water inhabitants. This ancestor may have frequented marine caves from which it could have progressively penetrated into limestone anchialine caves to considerable distances from the sea (Anker & Iliffe, 2000).
Conservation Status: Restricted to four anchialine caves from Bermuda. One of these caves, Bat Cave at Government Quarry, was grossly polluted when rubbish was bulldozed into the cave pool and was subsequently destroyed by quarrying in the mid 1980's (Iliffe et al., 1984).
Contributor: Dr. Arthur Anker, University of Alberta, Edmonton, Canada
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