Huysia bahamensis

Phylum Arthropoda
Subphylum Crustacea
Class Copepoda
Order Misophrioida
Family Misophriidae

Huysia bahamensis Jaume, Boxshall, & Iliffe, 1998

Taxonomic Characterization: Huysia bahamensis is the only described species of this genus. The genus Huysia is characterized by "the unique combination of a derived 2-segmented endopod in leg 1 and a plesiomorphic 1-segmented endopod in leg 5 of both sexes" (Jaume, Boxshall, and Iliffe, 1998). This genus/species has the following characteristics:

The cephalosome is not produced posteriorly into a carapace-like extension.
The first pedigerous somite is free.
The female urosome has five segments. The genital and first abdominal somites fused to form genital double-somite.
The single copulatory pore opens ventrally.
The caudal rami are armed with seven setae.
The antennules have 25 segments in both sexes. They have compound proximal and apical segments, which are derived from ancestral segments I-III and XXVII-XXVIII, respectively.
The proximal segment (I-III) is swollen dorsolaterally, forming a lobe with elongate aesthetascs on segments 1 (III) and 5 (VII).
The maxillulary basal exite is absent.
The Allobasis of maxilla has armature formula [5,3].
The maxilliped syncoxa are lacking praecoxal seta. The endopod has six segments and the setal formula is [1,2,2,2,2+1,5].

Ecological Classification: Stygobitic

Size: Adult females' length range from 0.60 to 0.62 mm. The adult male allotype was 0.50 mm long.

Number of Species in Genus: One

Species Range: Known only from Norman's Pond Cave, Norman's Pond Cay, Exuma Cays, Great Bahama Bank, Bahamas

Closest Related Species: It is the only species within the genus. Huysia is very closely related to three other genera - Speleophria, Speleophriopsis, and Protospeleophria. The most closely related genus/species is Protospeleophria lucayae Jaume, Boxshall & Iliffe, 1998. It was also discovered in Norman's Pond Cave and was described with H. bahamensis.

Habitat: Anchialine limestone cave

Ecology: Fully marine salinity waters (35-37 g/l). Found free swimming in the water column at a depth of 10-25 m. Certain morphologic characteristics are indicative of taxa that temporarily burrow into loose sediments. These characteristics include a "laterally compressed prosome, the lobe on the proximal part of the antennules, the modified articulations between the posterior abdominal somites. . .and the stout distal setae on the swimming legs" (Jaume, Boxshall, and Iliffe, 1998).

Life History: Not known. Four copepodids were collected but not described.

Evolutionary Origins: Misophrioid copepods are believed to be composed of two ancestral lineages - Archimisophria and Misophira (Boxshall, 1989). The taxonomic characteristics of the loss of the aesthetasc from the ancestral antennulary segment XVIII and the loss of one inner seta from the second endopodal segment of leg one indicates that H. bahamensis is of the Archimisophria lineage. However, H. bahamensis retention of its biramous fifth legs is characteristic of the Misophira lineage.

Conservation Status: Restricted to a single cave in the Exuma Cays.

References:

Boxshall, G.A. 1989. Colonization of inland marine caves by misophrioid copepods. Journal of Zoology, 219:521-526.
Jaume, D., G.A. Boxshall and T.M. Iliffe, 1998. Two new genera of misophrioid copepods (Crustacea) from an anchihaline cave in the Bahamas. Journal of Natural History, 32:661-681, 11 figures, 1 table.

Damià Jaume, Instituto Mediterráneo de Estudios Avanzados (CSIC-UIB), Palma de Mallorca, Spain
Geoff Boxshall, Department of Zoology, The Natural History Museum, London, United Kingdom