Speleoithona bermudensis Rocha & Iliffe, 1993
Speleoithona bermudensis: habitus, lateral and dorsal views after Rocha & Iliffe, 1993
Taxonomic Characterization: Female: Body weak and diaphanous, making
it difficult to distinguish clearly articulations of body somites or appendage
segments. Forehead enlarged and notched medially in dorsal view. Posterior
margins of all body somites smooth. Genital double somite swollen ventrally and
expanded backwards at posterior corners. Copulatory pore placed medially at
posterior margin of somite. Copulatory duct straight and heavily sclerotized.
Anal somite as long as two preceding somites together. Caudal ramus as long as
long as anal somite and about 3 times longer than wide. Antenna 3-segmented.
Mandibular palp biramous. Maxillule with 3 spines and 1 seta on praecoxal
arthrite. Legs 1-4 with rami 3-segmented. Outer spines of legs 1-3 with lateral
serrate membrane. Outer spines of leg 4 diaphanous, smooth. Members of leg 5
joined by intercoxal sclerite. Leg 6 with spine curved forward and long smooth
seta. Male: Cephalosome without lateral flap and accompanying integumental
organs. Leg 6 with short, stiff seta curved dorsally and laterally, and long
dorsal seta. Antenna, mouthparts, swimming legs, and caudal rami as in female
(Rocha & Iliffe, 1993).
Disposition of Specimens: Type specimens were deposited in the National Museum of Natural History, Smithsonian Institution, Washington, D.C. (USNM 257015, 257025 and 257014) and in the Museu de Zoologia da Universidade de São Paulo (11379).
Ecological Classification: Stygobitic
Size: Female 260-290 microns, prosome:urosome ratio = 1.36-1.54 : 1. Male 255-300 microns, prosome:urosome ratio 1.43-1.52 : 1.
Number of Species in Genus: Three, all stygobitic
|Speleoithona: genus range|
Species Range: Known only from Walsingham and Bee Pit Caves in
Hamilton Parish, Bermuda.
Closest Related Species: Speleoithona salvadorensis and S. eleutherensis; but S. bermudensis has more spines on the exopods of legs 3 and 4, and by differences in the shape of the genital double somite, the structure of the maxillule, the segmentation and armature of the maxilliped, and the setation of the mandibular endopod 2 (Rocha & Iliffe, 1993).
Habitat: Anchialine limestone caves
Ecology: Marine, found in cave pools in 0-4 m depths and on submerged soil slopes at 0-1m depths.
Life History: Collected specimens included 21 females, 6 males and 5 copepodids.
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 & Iliffe, 1991).
Conservation Status: Restricted to two caves in Hamilton Parish, Bermuda.
Contributor: Carlos Eduardo F. da Rocha, Universidade de São Paulo,
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