Aponesidea iliffei Maddocks, 1986
Aponesidea iliffei: dorsal, right and left valve exteriors
Taxonomic Characterization: Aponesidea iliffei has a medium-sized carapace which is entirely smooth, translucent white, without opaque patches or with at most a slightly less transparent, central, vertical band. The shape is typically bairdian but very inflated and ventrally flattened. The anterior and posterior margins of the left valve are denticulate. The anterior and posterior margins of the right valve have striate frills. The third and fourth podomeres of the antenna are approximately equal in length. The distal claw is fairly short, smooth, and tapers to a slightly bent, blunt point in both sexes. However, the anterodistal seta is slender and short in the male, and slender and long in the female. The posterodistal fused claw is distally thickened, coarsely serrate at the tip, and has about 6 barbs tapering rapidly in size. The hemipenes is large and massive with a small hemicircular basal lobe, a large subquadrangular middle lobe, and a fairly large, rounded-subtriangular distal lobe. The copulatory tube is very long, curled at the base in a hemicircle that is as large as the hemipenis (Maddocks & Iliffe, 1986).
Disposition of Specimens: All specimens were deposited in the United States Museum of Natural History: male holotype (USNM 216436) and paratypes (USNM 216437-216440).
Ecological Classification: Stygobitic
Size: Length of left valve of adult female 0.87 mm, adult male 0.96 mm.
Number of Species in Genus: One
Species Range: Known from Cherry Pit, Cripplegate, Deep Blue, Fern Sink, Green Bay, Myrtle Bank, Palm, Straw Market, Walsingham Sink, and Walsingham Caves in addition to Harrington Sound in Bermuda (Maddocks & Iliffe, 1986).
Closest Related Species: The external appearance of Aponesidea iliffei is intermediate between and can readily be confused with Neonesidea omnivaga and Havanardia keiji, two species with which it commonly occurs. Thus, careful attention must be paid to the degree of inflation, ventral flattening, and lateral outline (Maddocks & Iliffe, 1986).
Habitat: Anchialine limestone caves
Ecology: Empty shells of A. iliffei are abundant in cave sediments since this species characteristically dwells in caves and cryptic habitats with low standing populations and low sedimentation rates. Specimens were collected in silty bottom sediment with a fine-mesh hand net and with a 30 cm diameter plankton net in 0-14 m water depth in numerous Bermudian caves that connect directly or indirectly with Harrington Sound. No specimens from this species have yet to be found in shallow-water lagoon or reef sediment samples from open water environments of the Bermuda platform (Maddocks & Iliffe, 1986).
Life History: Collected specimens included 1 male, 4 females, 9 juveniles, and 163 empty valves.
Evolutionary Origins: Aponesidea is an important link between the small, ordinary bairdians such as Neonesidea and Paranesidea with the punctuate, alate, reef-specialized Havanardia and perhaps Pterobairdia (Maddocks & Iliffe, 1986).
Contributor: Dr. Rosalie F. Maddocks, University of Houston, Houston, Texas USA
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