Ambicholestes, 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 : 30-31

Ambicholestes n.gen.

Diagnosis. Concholestid Siphonoecetinae (sensu Just, 1988) with inner ramus of uropod 1 at most 112 length of outerramus,flattened, withrobustsetaeonmargin. Uropod 3 without ramus. Mandibular palp blunt or pointed, with or without small second article. Inner lobes of lower lip complexly lobate. Ocular field of eye lobes inflated. Article 2 of pereopod 7 with marginal setae and midlateral, single, longitudinal row of setae. Oostegites on pereopods 2-5. Gills on pereopods 4-6.

Type species. Caribboecetes magellani Just, I 984a.

Additional species. Ambicholestes berentsae n.sp., A. crassicornis (Just, I984a) n.comb., A. cygnatratus n.sp., A. minutus n.sp., A. poorei n.sp., A. squamiferus (Just, I984a) n.comb., A. thetis n.sp., A. trilobatus n.sp.

Further description. Rostrum present or absent. Coxal plates 5 and 6 posterolobate only. Upper lip with apical notch. Antenna 1 article 3 55-85% length of article 1, article 1 85-95% length of article 2. Antenna 2 peduncular article 4 75-90% length of article 5. Antenna 1 reaching from middle of to just beyond peduncular article 5 of antenna 2. Pereopod 1 article 6 subequal in length to article 5 (± 10%), with or normally without posteroapical triangulartooth, withposteroapicalrobustsetaandvarying number of posterior robust setae; article 5 normally with posteroapical robust seta. Pereopod 2 article 6 subequal in length to article 5 (± 10%), with posteroapical triangular tooth and varying number of posterior robust setae; article 5 with I posteroapical robust seta. Pereopods 3 and 4 with posterior short, robust setae on article 5. Pereopods 5 and 6 with crescent of short, equal-sized robust setae on article 5. Pleopods with peduncle broader than long, rami at most as long as width of peduncle, inner ramus slightly longer than outer ramus.

Distribution. The Philippines ( A. magellani , A. squamiferus ), Guam ( A. squamiferus , new record), Caribbean ( A. crassicornis ), Australia (see Fig. 1 ); 0.l- 229 m.

Etymology. The genus name is derived from the Latin ambifarius = with two sides, referring to the bimodal distribution of the genus (South East Asia-Australia and the Caribbean), combined with an allusion to its concholestid affinity. Masculinum.

Ambicholestes (Ambicholestes) squamiferus (Just, I984a), n.comb.

Caribboecetes squamiferus Just, 1984a: 59 , figs ID, 18, 19.

Material examined. Agana Bay, Guam, on rubble, 12.8 m, 25 April 1984, Stn GUM 112 D, J.H. Dominguez and R. K. Kropp, NMNH (11 specimens in small prosobranch shells). Pago Bay, Guam, underfin algal mat at outer reef flat, intertidal, 1 November 1984, Stn GUM 189 , R. K. Kropp, NMNH (62 specimens in similar abodes), AM P44613 (10 specimens in similar abodes), Guam Marine Laboratory, University of Guam (10 specimens in similar abodes) .

This is the first record of Siphonoecetinae from Guam.

Figures

Fig. 1. Distribution of species of Ambicholestes in Australia. Arrow points towards Chesterfield Islands in the Coral Sea.