Synalpheus congoensis Crosnier & Forest, 1965

Anker, Arthur, Pachelle, Paulo P. G., Grave, Sammy De & Hultgren, Kristin M., 2012, 3598, Zootaxa 3598 (1), pp. 1-96 : 34

Synalpheus congoensis Crosnier & Forest, 1965 stat. nov.

Synalpheus hululensis congoensis Crosnier & Forest 1965: 608 , fig. 3; Crosnier & Forest 1966: 301, fig. 31a–g.

Material examined. Republic of the Congo: 1 male, holotype, MNHN-IU-2010-4120, Djeno rocks near Pointe Noire, intertidal zone, low tide, coll. A. Stauch , 1964; 5 specimens, paratypes, MNHN-IU-2010-4121, same collection data as for holotype ; 2 males, 1 ov. female (out of 15 specimens), MNHN-IU-2010-4122 [formerly MNHN-Na 13779], Djeno near Pointe Noire, rocky intertidal, small tide pools among rocks, coll. A. Crosnier, 04.04.1965.

Diagnosis. Rostrum subtriangular, longer than wide at base, only slightly longer than orbital hoods, flattened dorsally, base almost confluent with anterior margin of orbital hoods; orbital teeth acute, directed anteriorly; notches between orbital teeth and rostrum broad and deep. First abdominal somite in males acutely produced posteroventrally. Telson broad, tapering posteriorly, with lateral margins slightly convex anterior to mid-length; dorsal surface with two pairs of spiniform setae inserted at about half and 3/4 length of telson, respectively; posterior margin convex, distolateral angles blunt, with a pair of spiniform setae, mesial longer than lateral. Antennular peduncles with second article slightly longer than wide; stylocerite sharp, its tip not exceeding midlength of second article. Antenna with basicerite armed with sharp distodorsal tooth and stout, sharp ventrolateral tooth, latter reaching distal margin of first article of antennular peduncle; scaphocerite with moderately broad blade; distolateral tooth overreaching end of antennular peduncle but not reaching end of carpocerite. Third maxilliped with crown of eight-nine spiniform setae on tip of ultimate article. Major chela with palm less than twice as long as fingers; distal tooth small, flattened, blunt or subacute, sometimes reduced to small tubercle. Second pereiopod with carpus five-articlated, first article at least equal to sum of all others. Third pereiopod moderately slender, with merus slightly more than three times as long as maximal width; propodus armed with about six-seven spiniform setae on ventral margin (including distal pair); dactylus about 1/4 length of propodus, biunguiculate, proximal unguis shorter, more strongly curved than distal unguis. Uropodal exopod with one distolateal tooth adjacent to stout spiniform seta.

Description. For description and illustrations see Crosnier & Forest (1965, 1966), as S. hululensis congoensis .

Size range. Examined material: males, 4.4–5.0 mm cl; female, 5.7 mm cl; range of type specimens: 9.5–11 mm tl ( Crosnier & Forest 1966).

Colour in life. Unknown.

Type locality. Pointe Noire , Republic of the Congo .

Distribution. Eastern Atlantic: presently known only from Republic of the Congo (see map in Fig. 51 ).

Ecology. Rocky intertidal pools ( Crosnier & Forest 1966); apparently free-living, not associated with sponges.

Remarks. The main differences between S. africanus and S. congoensis lie in the shape of the rostrum, which is dorsally convex and narrow at the base in S. africanus and flat and wider at the base in S. congoensis ( Crosnier & Forest 1966: Figs 29a , 31a ). Further, S. africanus differs from S. congoensis in the more slender second and third pereiopods ( Crosnier & Forest 1966: Figs 29e, f , 31e, f ), and in the longer and more slender carpocerite of the antenna ( Crosnier & Forest 1966: Figs 29b , 31b ). Slight differences were also found in the number of spiniform setae on the tip of the third maxilliped (8–9 in S. congoensis vs. 6–7 in S. africanus ) and on the propodus of the third pereiopod (6–7 in S. congoensis vs. 8–9 in S. africanus ); however, their consistency needs to be investigated further. In addition, S. africanus and S. congoensis may also be geographically separated, the former species being found from the tropical Gulf of Guinea northwards to the warm-temperate waters around the Canary Islands and the Mediterranean Sea, whereas the latter species is presently known only from the tropical continental waters of Congo.

Figures

FIGURE 29. Synalpheus goodei Coutière, 1909: a–d, ovigerous female from Bocas del Toro, Panama (OUMNH.ZC.2012-07- 052); e, f, ovigerous female from Isla Grande, Panama (MNHN-IU-2010-4140), in dorsal view (e) and with host sponge (f); g, h, male of S. goodei (?) from Bocas del Toro, Panama (RMNH D54868). Photographs by A. Anker.

FIGURE 31. Synalpheus hemphilli Coutière, 1908: a, b, male from Bocas del Toro, Panama (RMNH D54864), in dorsal view (a) and in the spongocoel of Haliclona sp. (b). Photographs by A. Anker.

FIGURE 51. Presently known geographic ranges of Synalpheus africanus Crosnier & Forest, 1965; S. cf. africanus (eastern and western Atlantic); S. agelas Pequegnat & Heard, 1979; S. anasimus Chace, 1972; S. antillensis Coutière, 1909; S. apioceros Coutière, 1909; S. bocas Anker & Tóth, 2008; S. bousfieldi Chace, 1972; S. brooksi Coutière, 1909; S. carpenteri Macdonald & Duffy, 2006; S. chacei Duffy, 1998; S. congoensis Crosnier & Forest, 1965; S. dardeaui (Ríos & Duffy, 2007); S. dominicensis Armstrong, 1949; S. elizabethae (Ríos & Duffy, 2007); S. filidigitus Armstrong, 1949; S. fritzmuelleri Coutière, 1909; S. goodei