Neonesidea omnivaga Maddocks, 1986
Neonesidea omnivaga: dorsal, right and left valve exteriors
Taxonomic Characterization: The female of Neonesidea omnivaga has a smooth carapace that is translucent white with amber setae and small, elongate, central opaque spot but no other opaque spots. The greatest thickness is located at about one-third length, just anteroventral to muscle-scar pattern. The carapace tapers continuously from there in all directions. There are adductor muscle scars grouped into four elongate scars. The left valve has an angulate, five-sided lateral outline, weak ventral indentation, and only moderately extended caudal extremity, with a few very tiny posteroventral marginal denticles. The right valve is smaller, more angulate, and lacks marginal denticles. The appendage structure is normal for the genus. It is presumed males that males are smaller and not as high, though there are no soft parts available (Maddocks & Iliffe, 1986).
Disposition of Specimens: All specimens were deposited in the United States Museum of Natural History: female holotype (registration number 216426), paratypes (registration numbers 216427-216431).
Ecological Classification: Possibly stygophilic or accidental
Size: Length of right valve of adult female holotype 0.54 mm.
Number of Species in Genus: At least 13.
Species Range: Known from Cherry Pit, Green Bay and Palm Caves, plus Harrington Sound, reefs and lagoons of North Lagoon, and the South Shore in Bermuda (Maddocks & Iliffe, 1986).
Closest Related Species: Neonesidea omnivaga is similar to a species reported as N. gerda from Florida and the Bahamas and as N. longisetosa from Belize, although this species is twice as large, has somewhat more rounded contours, and additional anterior, posterior, and posterodorsal opaque spots. The thoracic legs of N. gerda have more elongate distal podomeres and claws. Bairdia crosskeyana is similar in shape but larger and more elongate with a gently arched dorsal margin (Maddocks & Iliffe, 1986).
Habitat: Anchialine limestone caves and open water environments
Ecology: Specimens of N. omnivaga were collected with a fine-mesh hand net from bottom silt and gravel in 3-11 m water depths in caves, from hydroids attached to the diving line in Green Bay Cave at 16 m water depths, and from inshore waters, reef and lagoon sediments. Bairdiacea are sediment-eating epibenthos. Unable to swim, they craw freely over all benthic surfaces. Higher diversity of Bairdiacea characterizes coralline fauna and those of other tropical habitats with coarse grained sediment and abundant sessile invertebrates (Maddocks & Iliffe, 1986).
Life History: Collected specimens included 9 females, 2 juveniles, 4 empty valves, and 50 subfossil specimens.
Evolutionary Origins: N. omnivaga is very common in open water environments and is one of the most common species of Bairdiacea on Bermuda. Their presence in caves shows open connection to the outside (Maddocks & Iliffe, 1986).
Contributor: Dr. Rosalie F. Maddocks, University of Houston, Houston, Texas USA
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