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Phylum Arthropoda
Subphylum Crustacea
Class Copepoda
Order Cyclopoida
Family Speleoithonidae

Speleoithona salvadorensis Rocha & Iliffe, 1991


Taxonomic Characterization:
A minute diaphanous anchialine cyclopoid. The genus Speleoithona is distinguished from other cyclopoids by several characteristics. The rostrum is enlarged and notched medially. The inner apical seta on the caudal rami is absent. The mandible has a smooth and quadrangular basal segment 2, and a 2-segmented endopodite with an unarmed proximal segment and 3 setae on the terminal segment. The antennule is 18-segmented, with aesthetascs on segments 8,17, and 18. On the second through fourth legs, the endopodite 3 has a row of pinnules on the caudal face. The fifth legs are 2-segmented, bear long seta, and are joined by an intercoxal plate. In males, the fifth legs also have 2 short setae on the inner side of the distal segment. S. salvadorensis can be distinguished from other Speleoithona by the following characteristics:

  • On the endopodite of the fourth leg the armature is 0-0;0-2;1,2,1.
  • The caudal rami 2.13 to 2.25 times longer than wide. The median apical setae taper gradually toward the tips and is plumose terminally. The outer seta is 3.8 times longer than the ramus and 1.4 times longer than the inner seta. The dorsal seta reaches the tip of the inner median apical setae.
  • The terminal segment of the fifth leg on both sexes bears hair on the inner and outer sides. The basal segment is the same length as the terminal segment.
  • In males, the sixth legs have two unequal setae.

Ecological Classification: Stygobitic

Size: Adult females' lengths range from 250 to 285 microns. The adult males' lengths range from 230 to 250 microns.

Number of Species in Genus: Three, all anchialine stygobitic

Genus Range:

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Speleoithona: genus range

Species Range: Known only from Lighthouse Cave, San Salvador Island, Great Bahama Bank, Bahamas

Closest Related Species: Speleoithona eleutherensis from Eleuthera

Habitat: Anchialine limestone cave

Ecology: They were free-swimming, at a depth of 0-1 m and in near fully marine salinity water (32 g/l).

Life History: 24 females, 6 males and 2 copepodites were collected. After copulation, females bear a pair of spermatophores that are attached side by side at a ventral position.

Evolutionary Origins: Speleoithonidae is considered to be a sister group of Oithonidae. It is believed that Speleoithona evolved in its restricted habitat, developing very characteristic features, while retaining some primitive traits (Rocha and Iliffe, 1991).

Conservation Status: Restricted to a single cave on San Salvador Island, Bahamas

Reference:

  • Rocha, C.E.F. and T.M. Iliffe. 1991. Speleoithonidae, a new family of Copepoda (Cyclopoida) from anchialine caves on the Bahama Islands. Sarsia, 76:167-175, 28 figures.
  • Rocha, C.E.F. and T.M. Iliffe. 1993. New cyclopoids (Copepoda) from anchialine caves in Bermuda. Sarsia, 78:43-56, 45 figures.

Links:

Contributor: Carlos Eduardo F. da Rocha, Universidade de São Paulo, Brazil


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