Hyachelia J.L. Barnard, 1967

Serejo, Cristiana S. & Sittrop, Daniela J., 2009, Hyalidae *, Zootaxa 2260 (1), pp. 440-452 : 441

Hyachelia J.L. Barnard, 1967

Diagnosis. Maxilla 1 with palp vestigial or reaching base of the outer ramus setal-teeth. Article 4 of maxilliped blunt to triangular with normal (short) or whip-like (very long) distal setae in males. Gnathopods 1–2 subchelate, male gnathopod 2 enlarged and lacking a produced lobe on carpus. All pereopods prehensile with grasping robust setae. Uropod 1 without inter-ramal robust seta. Urosomite 3 obscure, uropod 3 lacking rami, peduncle narrowing distally with 1–2 distal robust setae. Telson formed of two separated lobes narrowing distally.

Remarks. Hyachelia has been, until the present study, a monotypic genus described by J.L. Barnard (1967), based on the species Hyachelia tortugae J.L. Barnard, 1967 , collected from the sea-turtle Chelonia mydas ( Linnaeus, 1758) at the Galapagos Islands. With the discovery of H. lowryi sp. nov. some generic characters are herein revised, which expands to some extent its diagnosis as pointed above in a bold text. The reduction in size of the maxillary palp within the Talitroidea is the rule. However, in some species it is partially reduced as seen in Lelehua myersi sp. nov. within the subfamily Hyalinae (reaching the base of the outer lobe setal-teeth); it can be very reduced (not reaching the base of the outer lobe setal-teeth) as seen in H. tortugae and groups such as Talitridae and Dogielinotidae or it can be absent as seen in the chiltoniids ( Serejo 2004). Despite these differences in the maxillary palp, and in the maxilliped, unique characters within the Talitroidea , such as the prehensile pereopods 3–7 and the reduction of urosome 3 with lose of rami were observed and are used to maintain these species in the same genus. These characters are probably a response to a commensal lifestyle on sea-turtles. Also, coxae 1–4 do not have posterior processes, a character commonly found in Hyalinae and not in Hyacheliinae ( Serejo 2004).