Antrisocopia prehensilis Fosshagen, 1985
Antrisocopia prehensilis: lateral view, after Fosshagen & Iliffe, 1985
Taxonomic Characterization: The female A. prehensilis is slightly compressed dorsoventrally and the prosome is ovoid in dorsal view. All 5 pedigers are free, the last one being rounded. The urosome is 5-segmented, about half the length of the prosome and the rostrum is strong and ends in a single point. The proximal part of the 1st antenna is greatly thickened and the 2 rami are widely separated in the 2nd antenna. The 2nd maxilla is strongly prehensile. The male is more dorsoventrally compressed than the female. The male differs from the female mainly in the geniculate 1st antennae on both sides. A. prehensilis is unique because of this genticulation, and due to well-developed 5th legs that are similar in both sexes with 3-segmented rami and in the 5-segmented urosome.
Antrisocopia prehensilis: dorsal view, after Fosshagen & Iliffe, 1985
Disposition of Specimens: Type specimens deposited in the American Natural History Museum: male holotype (AMNH Cat. No. 11 316), 1 male and 2 female paratypes (AMNH Cat. No. 11 317).
Ecological Classification: Stygobitic
Size: Total body length in males was 0.34 mm and 0.35 mm. Total body length in females was 0.35 mm and 0.37 mm.
Number of Species in Genus: A. prehensilis is the only species in the genus.
Species Range: Known only from Roadside Cave, Hamilton Parish, Bermuda (Fosshagen & Iliffe, 1985).
Closest Related Species: Antrisocopia resembles the aberrant genus Platycopia by its two spines on the outer margin of the 1st segment of the exopods, a 1st antenna with its distended proximal part and jointed aesthetascs, a similar mandible and 1st maxilla and in similarities of the urosome between both sexes. P. inornata has the same segmentation of the 2nd-4th legs and its male 1st antennae is also symmetrical with fused segments. A new order, Platycopioida, was erected to include Antrisocopia and Platycopia (Fosshagen & Iliffe, 1985).
Habitat: Anchialine limestone cave
Ecology: A. prehensilis inhabits Roadside Cave which is located 110 m inland from Harrington Sound. It has no visible connection with the sea or other caves. Tides in the pool are 57% of those in the open ocean with a lag time of 80 min. The water in the pool is very clear with no visible particles. The cave may serve as a refugium for rare and less competitive species. Specimens were collected using a long-handled dip-net at 0-1.5m depths. A. prehensilis is a raptorial feeder and a bottom-dweller, unusual for a copepod.
Life History: Collected specimens included 2 copepodids, 2 males and 3 females.
Evolutionary Origins: A. prehensilis appears to have retained some primitive features from the gymnopleans. The species agrees with a description of a theoretical ancestral copepod in having the same number of body segments and bilateral geniculate 1st antennae in the male as the only sexual dimorphism. Antrisocopia can be regarded as a "living fossil".
Conservation Status: A. prehensilis is considered to be critically endangered (IUCN, 1996). It is restricted to a single anchialine cave.
Contributor: Audun Fosshagen, University of Bergen, Norway
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