Falklandellidae, 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 : 35

Falklandellidae fam. nov.

Type genus. Falklandella Schellenberg, 1931 .

Included genera. Falklandella Schellenberg, 1931 ; Praefalklandella Stock & Platvoet, 1991 .

Diagnostic description. Head eyes absent. Calceoli present, gammarid (type 1). Antenna 1 longer than antenna 2; peduncular article 1 longer than article 2; accessory flagellum minute. Antenna 2 peduncular article 1 bulbous. Mandible incisor dentate. Labium without inner plates. Maxilla 1 inner plate strongly setose along medial margin; palps alike. Maxilla 2 inner plate with oblique setal row. Maxilliped inner plate well developed; outer plate small. Body laterally compressed. Coxal gills present on coxae 2 to 7, unstalked. Sternal gills present, simple or bifurcate. 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 with well developed posteroventral lobe. Pereopods 5–7: progressively longer; dactyli with a few subterminal setae; basis expanded. Pereopod 5 coxa with posteroventral lobe. 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 biramous; rami not sexually dimorphic; without fringing plumose setae; inner ramus shorter than outer ramus; 1-articulate. Telson emarginate, without robust setae.

Remarks. Falklandellids are enigmatic amphipods. The bulbous article 1 of antenna 2, simple sternal gills, unstalked coxal gills and biramous third uropods put them near the paramelitids. However as pointed out by Stock & Platvoet (1991) their calceoli are gammarid-like and falklandellids are ‘in reality ‘aberrant’ gammaroids’.

For us falklandellids and paraleptamphopids are both ancient Pangaean families probably near the base of the freshwater amphipod radiation. Both families apparently have gammarid-like calceoli. Falklandellids differ from paraleptamphopids as follows: maxilla inner plate with an oblique setal row (absent in paraleptamphopids); sternal gills present, simple or bifurcate (absent in paraleptamphopids); gnathopod 1 similar in size and form to gnathopod 2 (gnathopod 1 larger than gnathopod 2 in paraleptamphopids); gnathopod 2 paramelitid type, palm slightly acute with defined corner (crangonyctid type with acute palm in paraleptamphopids); pereopod 4 coxa with well developed posteroventral lobe (posteroventral lobe small in paraleptamphopids); pereopod 5 coxa with posteroventral lobe (coxa shallow and equilobate in paraleptamphopids).

Distribution. South America.