Africorchestia tricornuta ( Shoemaker, 1920 )

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 : 65

Africorchestia tricornuta ( Shoemaker, 1920)

( Fig. 7 )

Talorchestia tricornuta Shoemaker, 1920: 374 , figs 4–6. ― Schellenberg, 1939: 133, figs 21–28. ― Mateus & Mateus, 1966: 183. ― Coleman & Leistikow, 2001: 5, figs 12–17.

Types. Holotype, male, 11 mm, AMNH. Paratypes: female, 8 mm, AMNH; 48 specimens, AMNH.

Type locality. Banana, Democratic Republic of the Congo (~ 6°1’S 12°24’E) and Soyo (as Santo Antonia), Angola (~ 6°7’60”S 12°22’E).

Diagnosis. Based on male. Gnathopod 2 propodus ovate, palm extremely acute, convex, extending along entire posterior margin, without distal sinus or protuberence, with one row of large robust setae halfway along margin, with palmar protuberance towards center, posteroproximal corner defined by 2 slightly curved spines; dactylus much longer than palm. Pereopods 6–7 much longer than pereopods 3–5. Pereopod 6 much longer than pereopod 7; basis enlarged, broadly expanded posteriorly. Pleonite 1 without dorsal spines. Pleonite 2 with pair of dorsodistal spines. Pleonite 3 with 1 recurved mid-dorsal spine. Uropod 3 ramus subequal in length to peduncle, 3.2 x as long as broad. Telson entire apically notched, with 5 lateral and apical robust setae on each side.

Remarks. Africorchestia tricornuta is the only species without dorsal spines on pleonite 1. It also has elaborate spines on the palm of gnathopod 2 not seen in other member of the genus. Mateus & Mateus (1966) attributed one damaged male, 8 mm in length, from the island of Príncipe to A. tricornuta . This is far north of the known distribution of the species.

Distribution. Angola. Landana, Cabinda, ~ 5°13’S 12°08’25”E ( Schellenberg, 1939; Coleman & Leistikow 2001); Soyo, Bengo, ~ 6°8’S 12°22’E (as Santo Antonio, Shoemaker, 1920). Democratic Republic of the Congo. Banana, ~ 6°1’S 12°24’E ( Shoemaker 1920); Banana, Muanda ( Schellenberg 1939). Democratic Republic of São Tomé and Príncipe. Príncipe: Praia Pequena, ~ 1°38’N 7°27’E ( Mateus & Mateus, 1966).

Figures

FIGURE 7. Africorchestia tricornuta (Shoemaker, 1920), habitus, male. Landana, Democratic Republic of the Congo (after Coleman & Leistikow 2001).