Phylum Arthropoda
Subphylum Crustacea
Class Remipedia
Order Nectiopoda
Family Speleonectidae

Speleonectes minnsi Koenemann, Iliffe & van der Ham, 2003


Taxonomic Characterization: A small to medium-sized, slender species with 30 trunk segments; pleural tergites developed, broadly rounded, becoming angular in posterior part of trunk; sternal bars isomorphic; frontal filaments with long processes; antennules with short dorsal flagella; segment 4 of maxillule expanded; maxillulary claw very long; maxilla and maxilliped exhibiting tagmosis (i.e., proximal segment is much longer and wider than distal segment), setation sparse; arc of horseshoe-type claw composed of 7 small denticles; anal somite longer than wide; caudal rami shorter than anal somite (Koenemann et al., 2003).

	Speleonectes minnsi after Koenemann et al., 2003

Ecological Classification: Stygobitic

Size: To 18 mm

Number of Species in Genus: Nine, all stygobitic

Genus Range:

Species Range: Know only from Basil Minns Blue Hole, Great Exuma Island, Exuma Cays, Bahamas.

Closest Related Species: S. minnsi is morphologically closely allied with S. epilimnius from San Salvador and S. gironensis from Cuba.

Habitat: Anchialine limestone caves

Ecology: S. minnsi was collected from below a hydrogen sulfide layer in 33-43 m depths of an isolated, collapse, dome room located several hundred meters into the cave from the surface entrance.  In the depth range in which remipedes were collected, salinity was about 34 ppt, temperature 25^oC, pH 7.4 and dissolved oxygen 3 mg/l.  Three new species of Speleonectes were collected from this cave including S. tanumekes, S. parabenjamini and S. minnsi.  However, the sympatry of these three species is not exceptional for remipedes as several other instances of 2-3 sympatric species have been observed. Sympatric remipedes are likely to be subjected to strong competition, which could lead either to niche differentiation or competitive exclusion.  S. tanumekes appears to be the most abundant remipede in this cave. Other stygobitic fauna from this cave includes copepods, ostracods, leptostracans, bochusaceans, amphipods, thermosbaenaceans, mysids, and polychaetes (Koenemann et al., 2003).

Life History: The fact that remipedes are hermaphrodites may point towards an adaptation to small population size (Koenemann et al., 2003).

Evolutionary Origins: Remipedes are an ancient group of crustaceans sharing several well defined features with Tesnusocaris goldichi from the Carboniferous.  The current distribution of remipedes consists of a prominent cluster in the northern Caribbean including the Bahamas.  Whether this cluster is an ancient center of origin and the disjunct taxa in the Canary Islands and Western Australia are isolated relicts remains to be seen (Koenemann et al., 2003).

Conservation Status: Known only from one anchialine cave on Great Exuma Island.

References:

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Contributor: Stefan Koenemann, University of Amsterdam, The Netherlands.