Phylum Arthropoda
Subphylum Crustacea
Class Copepoda
Order Calanoida
Family Fosshageniidae

Fosshagenia ferrarii Suárez-Morales & Iliffe, 1996


Taxonomic Characterization: It is the only known species within the superfamily Fosshagenioidea. It is distinguished by the presence of lateral processes on the genital double-somite of the female and the first urosomal somite of the male. The superfamily, family, genus, and species have the following characteristics:

Cephalosome fused with first pediger. Rostrum blunt. Pedigers 4 and 5 partly fused. Urosome is 4-segmented in females, 5-segmented in males. First antenna 24-segmented, with segments 8 and 9 fused. Mouthparts reduced. Caudal ramus relatively elongate in females, slightly arched on middle inner portion; short, symmetrical, and straight in males. Caudal ramus with 3 long slender terminal setae in both sexes. Endopod of first leg 2-segmented, endopod of legs 2-4 and exopod of legs 1-4 3-segmented. Exopod of legs 2-4 with 1 long, serrate apical spine and 3 short outer spines. Third exopodal segment of leg 1 with 5 setae. Fifth legs apparently uniramous in females, 3-segmented with articulated structure in middle inner margin of basipodite. Male right antennule geniculate. Fifth legs modified into complex grasping organ; right exopod with bulbous terminal segment, left exopod 2-segmented, left endopod reduced.
		Fosshagenia ferrarii: dorsal view, after Suárez-Morales & Iliffe, 1996

Ecological Classification: Stygobitic

Size: Adult females' length range from 0.60 to 0.70 mm. The adult male's length range from 0.687 to 0.705 mm. It is the smallest recorded anchialine calanoid species.

Number of Species in Genus: One

Genus Range:

Turks and Caicos Islands: Middle Caicos Island: Fosshagenia ferrarii Suárez-Morales & Iliffe, 1996

Species Range: Known only from Conch Bar Cave, Middle Caicos Island, Turks and Caicos Islands.

Closest Related Species: It is the only known species within the superfamily Fosshagenioidea. The fosshagenioids may be closely related to the brackish-water dwelling species of the superfamily Centropagoidea, which is composed of only brackish and freshwater-dwelling species.

Habitat: Anchialine limestone cave

Ecology: They were free-swimming, at a depth of 0-0.5 m in brackish waters (23 g/l). Generally, the depth of the water in the Conch Bar Cave ranged from 0.5 to 1 m. Brown organic-rich silt lined the bottom of the pools. Morphological characteristics of F. ferrarii's mouthparts indicate it is a predator in the water column. This is dissimilar to other anchialine copepods, which are usually bottom-dwellers.

Life History: 19 adult females and 6 males, but no copepodids were collected.

Evolutionary Origins: Fosshagenoids are regarded as less primitive anchialine copepods, more closely related to brackish water forms than to other anchialine groups.

Conservation Status: Restricted to a single cave on Middle Caicos Island.

References:

Links:

Contributor: Eduardo Suárez-Morales, Colegio de la Frontera Sur (ECOSUR), Chetumal, Quintana Roo, Mexico