Chillagoeidae, Lowry & Myers, 2012

Lowry, J. K. & Myers, A. A., 2012, New, mainly southern hemisphere, freshwater families of Amphipoda (Crustacea), together with a description of the first freshwater calliopiid, Lutriwita bradburyi gen. nov. et sp. nov., Zootaxa 3499, pp. 27-45 : 32-33

Chillagoeidae fam. nov.

Type genus. Chillagoe Barnard & Williams, 1995 .

Included genera. Chillagoe Barnard & Williams, 1995 .

Diagnostic description. Head eyes absent. Calceoli absent. Antenna 1 longer than antenna 2; peduncular article 1 longer than article 2; accessory flagellum short. Antenna 2 peduncular article 1 bulbous. Mandible incisor dentate. Labium without inner plates. Maxilla 1 inner plate setose apically; palps alike. Maxilla 2 inner plate without oblique setal row. Maxilliped inner plate well developed; outer plate small. Body laterally compressed. Coxal gills present on coxae 2 to 6, unstalked. Sternal gills present, simple. Gnathopods 1 and 2

male not known. Gnathopod 1 similar in size and form to gnathopod 2; propodus without robust setae along palmar margin. Pereopod 4 with small posteroventral lobe. Pereopods 5–7: pereopod 5 shorter, pereopods 6 and 7 similar length; dactyli with a few subterminal setae. Pereopod 5 coxa with small anteroventral lobe; basis slightly expanded. Urosomites 1 to 3 free, with robust dorsal setae. Urosomite 1 with distoventral robust seta. Urosomite 2 with paired dorsal setae. Uropod 1 peduncle with 1 or 2 small basofacial robust setae; without ventromedial spine. Uropod 3 uniramous; rami not sexually dimorphic; without fringing plumose setae; inner ramus minute; 2- articulate, outer ramus article 2 short. Telson deeply cleft, with small robust setae.

Remarks. Chillagoeids are the only ‘crangonyctoid’ with a distoventral robust seta on urosomite 1 in combination with a basofacial seta on the peduncle of uropod 1. They have lost the inner lobes on the labium, the oblique setal row on the inner plate of maxilla 2 and they have unstalked coxal gills. Chillagoeids have simple sternal gills. All of these characters align them with the southern hemisphere ‘crangonyctoids’. The laterally compressed body, the loss of the oblique setal row on maxilla 2 and the well developed posteroventral lobe on coxa 4 separates chillagoeids from giniphargids and uronyctids, all of which have uniramous third uropods. the only difference between chillagoeids and paramelitids appears to be the basofacial setae on the peduncle of uropod 1, the small dorsal robust setae on urosomite 2 and the uniramous third uropods of chillagoeids. Chillagoeids alone among the southern hemisphere ‘crangonyctoid’ have a basofacial seta on the peduncle of uropod 1.

Distribution. Tropical Australian endemic.