Ambicholestes (Ambicholestes) trilobatus, Just, 1998

Just, Jean, 1998, Siphonoecetinae (Crustacea: Amphipoda: Ischyroceridae) 7: Australian Concholestids, Ambicholestes n. gen., with a Description of Six New Species, and a New, Restricted Diagnosis for Caribboecetes Just, 1983, Records of the Australian Museum 50 (1), pp. 27-54 : 35-37

Ambicholestes (Ambicholestes) trilobatus n.sp.

Figs 6-8

Material examined. HOLOTYPE: fully developed female, 3.5 mm, with empty marsupium, Long Island , Chesterfield Reef, Coral Sea, seaward face, 20 m, "Lady Basten", N.L. Bruce, 4 May 1979, QM Wl1668. Unique.

Diagnosis. Rostrum present in depressed position between antennae 1. Antenna 1 peduncle article 1 and antenna 2 peduncle article 3 (rest of antenna missing) partly covered withmicrosetules. Anteriormargin of cephalon and rostrum covered by microscales. Pleon and urosomites dorsally with dense cover oflong, very fine setules. Article 2 of pereopod 2 with anterior margin trilobate; presumed stridulation organ present.

Further description. Rostrum narrow, pointed. Antenna 1 peduncle article 1 with 2 recurved robust setae ventrally, with ventral to medial cover of microsetules. Antenna 2 peduncle article 3 with mid-medial robust seta, with dorsal to medial cover of microsetules; ventroapical projection of article 2 as long as wide, triangular, with 4 long lateral and 2 short medial setae.

Coxal plates 5 and 6 posterior lobe rounded with upturned part rounded. Distalmost part of plates 3 and 4, anterior lobe of plate 5, posterior lobe of plate 6, and anterior lobe of plate 7 with microscales. Pleonal sideplates 1 and 2 evenly rounded.

Mouthparts normal. Mandibular palp laterally to ventrally with lose cover of acute cuticular scales.

Pereopod 1 article 6 without posterodistal tooth, with 4 posterior robust setae. Pereopod 2 article 6 with 4 posterior robust setae; article 2 anterior margin proximal to lobate part with a few small marginal teeth.

Uropod 1 outer ramus about 5 times longer than broad, with 7 lateral robust setae; inner ramus ca. 40% length of outer ramus, with lateral and apical robust setae.

Urosomites 1 and 2 free. Urosomite 3 and telson fused dorsally, but with distinct subcuticular line of articulation.

Colour and biology. Not known.

Etymology. The specific epithet alludes to the shape of the anterior margin of pereopod 2 article 2.