Austroniphargidae Iannilli, Krapp & Ruffo 2011

Type genus. Austroniphargus Monod, 1925.

Included genera. Austroniphargus Monod, 1925; Davidia Iannilli, Krapp & Ruffo, 2011; Libertinia Iannilli, Krapp & Ruffo, 2011.

Diagnostic description. Head eyes absent. Antennae calceoli absent. Antenna 1 longer than antenna 2; peduncular article 1 longer than article 2; accessory flagellum short or minute. Antenna 2 peduncular article 1 bulbous. Mandible incisor dentate. Labium without inner plates. Maxilla 1 inner plate setose apically; palps dissimilar, left slender with apical slender setae, right swollen with apical robust setae. 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, stalked, with or without proximal suture. Sternal gills absent. Gnathopods 1 and 2 not sexually dimorphic. Gnathopod 1 similar in size and form to gnathopod 2; propodus without robust setae along palmar margin. Pereopod 4 without posteroventral lobe. Pereopods 5–7 similar in length; dactyli with a few subterminal setae. Pereopod 5 coxa with large anteroventral lobe; basis expanded. Urosomites 1 to 3 coalesced, without robust dorsal setae. Urosomite 1 with distoventral robust seta. Urosomite 2 without paired dorsal setae. Uropod 1 peduncle without basofacial robust seta; without ventromedial spine. Uropod 3 biramous or uniramous; rami not sexually dimorphic; without fringing plumose setae; inner ramus minute, 2-articulate, outer ramus article 2 short. Telson weakly cleft to entire, with robust setae.

Remarks. Austroniphargids fall into the ‘niphargidean’ group that have apically setose inner plates on maxilla 1 and stalked coxal gills. They have niphargid-like second gnathopods. Austroniphargids differ from other ‘niphargideans’, except sandroids, in having coalesced urosomites. Austroniphargids differ from sandroids as follows: labium without inner lobes (present in sandroids); maxilla 1 inner plate apically setose (setose along medial margin in sandroids); pereopod 4 coxa without posteroventral lobe (well developed in sandroids); pereopods 5–7 similar in length (pereopod 5 shorter than pereopods 6–7 in sandroids); urosomite 2 without paired dorsal setae (with paired dorsal setae in sandroids); and uropod 3 rami not sexually dimorphic (sexually dimorphic in sandroids).

Distribution. Madagascar endemic.