Africorchestia quadrispinosa ( K.H. Barnard, 1916 )

Lowry, James K. & Coleman, Charles Oliver, 2011, Africorchestia a new genus of sand-hoppers (Crustacea: Amphipoda: Talitridae) from western Africa and south-western Europe, Zootaxa 2825, pp. 55-68 : 58-60

Africorchestia quadrispinosa ( K.H. Barnard, 1916)

( Fig. 2 )

Orchestia Fischerii. ―Guérin, 1846: pl. 26, fig. 3, and 1843. Explication des Planches, p. 22. (non H. Edwards, 1830 and 1840.)

Orchestoidea Fischerii. ― Stebbing, 1910: 459 (in part).

Types. Syntypes, males and females, SAM 1256. 1283, A2514, A 2875 (largest male, 22 mm).

Type locality. Dassen Island (~ 33°25’S 18°05’E) and east and west coast of Cape Peninsula (~ 34°10’S 18°20’E), South Africa.

Diagnosis. Based on male. Gnathopod 2 propodus ovate, palm extremely acute, convex, extending about 75% of posterior margin, with rounded protuberance near dactylar hinge, with large distal sinus, with two rows of robust setae along entire margin, posteroproximal corner without spine; dactylus slightly longer than palm. Pereopods 6– 7 much longer than pereopods 3–5. Pereopod 6 much longer than pereopod 7; basis expanded posteriorly. Pleonites 1–2 each with pair of posterodistal spines. Pleonite 3 with paired vestigial posterodistal spines. Uropod 3 ramus longer than peduncle, 3.8 x as long as broad. Telson entire apically truncated with about 10 apical robust setae on each side.

Remarks. The geographic neighbors Africorchestia quadrispinosa and A. skoogi each have three dorsodistal spines on pleonite 1. They differ in the shape of male gnathopods 2 which is more ovate and does not have a posteroproximal spine on the propodus in A. quadrispinosa .

Distribution. Namibia. Walvis Bay, ~ 25°55’S 14°32’E ( Schellenberg 1925); Lüderitz Bay, ~ 26°39’S 15°09’E ( Schellenberg 1925; Penrith & Kensley 1970); Shearwater Bay ( Griffiths 1974); Skeleton Coast, 21°38’38”S 13°55’17”E and 26°44’09”S 15°05’40”E ( Coleman & Leistikow 2001); Orange River mouth, ~ 28°37’56.23”S 16°27’16.88”E ( Griffiths 1974). South Africa. Cape Peninsula, ( K.H. Barnard 1916).

Figures

FIGURE 2. Africorchestia quadrispinosa (K. H. Barnard, 1916), habitus, male. Grosse Bucht, Namibia (after Coleman & Leistikow 2001).