CHEIDAE Thurston, 1982

Souza-Filho, Jesser F., 2011, First record of the family Cheidae (Amphipoda, Gammaridea) from the Brazilian coast, with description of two new genera and new species, Journal of Natural History 45 (5 - 6), pp. 327-346 : 328-329

Family CHEIDAE Thurston, 1982

Diagnosis

Body rather short and stout, deep, lacking spines and carinae. Rostrum long, flattened, visor-like, of platyischnopid form, lacking posteriorly directed ventral process but with distal sensory organ on tip of rostrum; cheek strongly developed. Antenna 1 peduncle very short; primary flagellum rather short, not elongate in male and without calceoli; accessory flagellum well developed. Mandible with multidentate incisor; left lacinia mobilis with four or five teeth; right lacinia mobilis reduced or absent; molar small, conical, non-triturative, with robust distal setae. Lower lip with well-developed lobes. Maxilla 1 inner plate short, apically setose; outer plate short, with six or seven robust setae; palp, weak, 1- or 2-articulate. Maxilliped both inner and outer plate very reduced; four-articulate palp, dactylus long. Coxae 1–4 large, longer than wide, overlapping each other, forming a stepped intergrade; fourth largest, strongly excavate posteriorly. Coxae 5–7 bilobate, posterior lobe deeper. Gnathopods 1 and 2, subchelate, similar in shape and size to each other, palm obtuse. Pereopods 3–7 strongly fossorial, dactyls present; 3 and 4 subequal in length; 5–7 weakly heteropodous, 6 just longer than 7, basal articles similar, basal of 7 not phoxocephalid form. Urosome unarmed, not strongly flexed. Uropod 2 much smaller than uropod 1; uniramous or biramous, rod-like spinous. Uropod 3 biramous; rami lanceolate, foliaceous, inner ramus as long as or shorter than first article of outer. Telson deeply cleft; apices subacute, with robust setae. Sexual dimorphism very weak (modified from Thurston 1982).

Type genus

Cheus Thurston, 1982

Generic composition

Cheus Thurston, 1982 ; Microcheus gen. nov. and Ruffosius gen. nov.

Geographic distribution

South America: Falklands Islands , South Chile and Brazil (Rio de Janeiro, Santa Catarina and Rio Grande do Sul) .