Seborgiidae Holsinger, 1980

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 : 38

Seborgiidae Holsinger, 1980 (new status)

Type genus. Seborgia Bousfield, 1970 .

Included genera. Relictoseborgia Karaman, 1982 ; Seborgia Bousfield, 1970 .

Diagnostic description. Head eyes absent. Calceoli present. Antenna 1 subequal in length to antenna 2; peduncular article 1 longer than article 2; accessory flagellum minute. Antenna 2 peduncular article 1 bulbous. Mandible incisor dentate. Labium with inner plates. Maxilla 1 inner plate without setae; palps alike. Maxilla 2 inner plate absent; 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 proximal suture. Sternal gills absent. Gnathopods 1 and 2 not sexually dimorphic. Gnathopod 1 slightly larger (or stouter) or similar in size to gnathopod 2; propodus without robust setae along palmar margin. Pereopod 4 with well developed posteroventral lobe. Pereopods 5–7: similar in length; dactyli subterminal setae absent. Pereopod 5 coxa with posteroventral lobe; basis expanded. Urosomites 1 to 3 free, without robust dorsal setae. Urosomite 1 without distoventral robust seta. Urosomite 2 without paired dorsal setae. Uropod 1 peduncle without basofacial robust seta; without ventromedial spine. Uropod 3 uniramous; rami not sexually dimorphic; without fringing plumose setae; inner ramus absent; 1-articulate, outer ramus article 2 absent. Telson entire, without robust setae.

Remarks. Although seborgiids occur in fresh and brackish water they do not appear to be similar to other freshwater amphipods. They do not have apical robust setae on uropods 1 and 2, a characteristic of most freshwater amphipods. They have pedunculate coxal gills. They have a bulbous article 1 on antenna 2 (characteristic of most freshwater amphipods), but this may be an independent osmotic adaptation to freshwater.

There are many significant differences between sebids and seborgiids: antenna 2 peduncular article 1 bulbous in seborgiids; maxilla 2 inner plate absent in seborgiids (present in sebids); gnathopods 1 and 2 similar, gnathopod 2 subchelate (chelate in sebids); coxal gills stalked with proximal suture in seborgiids (not stalked in sebids); pereopod 5 shorter, pereopods 6 and 7 similar length in seborgiids (pereopod 5 to 7 similar in length in sebids); urosomites free in seborgiids (2–3 coalesced in sebids); outer ramus of uropod 3, 1-articulate in seborgiids (2- articulate in sebids).

Distribution. Texas; Mexico; Andaman Islands; Solomon Islands; Loyalty Islands, New Caledonia; Vanuatu; Vietnam.