Phylum Arthropoda
Subphylum Crustacea
Subclass Copepoda
Order Calanoida
Family Pseudocyclopiidae

Paracyclopia naessi Fosshagen, 1985

Paracyclopia naessi: dorsal view, after Fosshagen & Iliffe, 1985

Taxonomic Characterization: P. naessi is laterally compressed, robust and ovoid. When living, it is lacking in pigmentation. In females, there is fusion among the cephalosome and the 1st pediger and among the 4th and 5th pedigers. The urosome is 4-segmented and the rostrum is strong, directed downwards and ends in a single point. The 1st antenna is 24-segmented and slightly more than half the length of the prosome. The endopod of the 1st legs has 3 apical setae and 1 seta in the middle of the inner margin. The 2nd to 4th legs bear a strong spin; the 2nd and 3rd legs have strong spinules along the outer margin of the second basipodal segment and the first exopodal segment. The 5th legs are small and uniramous. The male differs from the female in the 5-segmented urosome, slightly in the 1st antenna and in the 5th legs.

Disposition of Specimens: Type specimens deposited in the American Museum of Natural History: female holotype from Devonshire Cave (AMNH Cat. No. 11 314), Devonshire Cave male paratype and Christie's Cave male and female paratypes (AMNH Cat. No. 11 315).

Ecological Classification: Stygobitic

Size: Total body length of 9 females ranged between 0.50 mm and 0.53 mm with an average of 0.52 mm. Total body length of 6 males ranged between 0.46 mm and 0.50 mm with an average of 0.49 mm.

Number of Species in Genus: 2, both of which are stygobitic.

Genus Range:

Species Range: Known only from Chalk Cave, Smith's Parish; Christie's Cave and Roadside Cave, Hamilton Parish; Devonshire Cave, Devonshire Parish; Southdown Cave and Tucker's Town Cave, St. George's Parish; all of Bermuda (Fosshagen & Iliffe, 1985).

Closest Related Species: P. gitana from the Balearic Islands in the Mediterranean is the only other species in the genus. P. naessi has mouthparts that are very similar to Pseudocyclopia stephoides.

Habitat: Anchialine limestone caves

Ecology: P. naessi inhabits six caves in Bermuda, all which lack a direct connection with the sea. Chalk Cave and Christie's Cave are c. 50 m from open water, Roadside Cave is 110 m and Tucker's Town Cave is 124 m from open water. Roadside Cave, Southdown Cave and Tucker's Town Cave have a tidal range of 57%, 48% and 62% respectively, that of the open water, and have tidal lag times of 80 min, 82 min and 58 min respectively. The most abundant population was found in Devonshire Cave, where 49 specimens were collected. Some of the specimens were observed swimming slowly along the substrate while the endopod of the maxilliped vibrated rapidly stirring up particles from the bottom. An adult female was collected from Devonshire Cave at a depth of c. 0.5 m. One male and one female were collected from Christie's Cave from 0-1.5 m depths. The specimens were collected on sight or by fine-meshed nets (less than 100 microns).

Life History: Collected specimens included 42 copepodids, 6 males and 22 females.

Conservation Status: P. naessi is considered to be critically endangered (IUCN, 1996). It is restricted to six hydrologically isolated anchialine caves in Bermuda.

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Contributor: Audun Fosshagen, University of Bergen, Norway