Synalpheus africanus Crosnier & Forest, 1965

Anker, Arthur, Pachelle, Paulo P. G., Grave, Sammy De & Hultgren, Kristin M., 2012, 3598, Zootaxa 3598 (1), pp. 1-96 : 5-8

Synalpheus africanus Crosnier & Forest, 1965 stat. nov.

( Figs 1 , 2 )

Synalpheus hululensis africanus Crosnier & Forest 1965: 607 , fig. 2; Crosnier & Forest 1966: 292, fig. 29a–g; Ribeiro 1968: 37, fig. 9; Lagardère 1971: 82, figs 159–167; Miya 1972: 63; Türkay 1982: 104; García Raso & Fernández Muñoz 1988: 306; González Pérez 1995: 77.

Synalpheus tumidomanus africanus — d’Udekem d’Acoz 1999: 107; Quiles et al. 2001: 10; Bacci et al. 2010: 821.

Synalpheus hululensis — Lewinsohn & Holthuis 1964: 49, fig. 2a–h; Kattoulas & Koukouras 1974: 374; García Raso 1988: 254, 257 (not S. hululensis Coutière, 1908 ).

Material examined. São Tomé: 1 male, OUMNH. ZC.2012-07-089, Boca do Inferno , rocky shore, under consolidated volcanic rocks and coralline algae, low tide, coll. A. Anker, N. Knowlton, 29.01.2006 [fcn 06-012*]; 1 female, OUMNH. ZC.2012-07-092, same collection data [fcn 06-013*]; 1 ov. female, OUMNH. ZC.2012-07-088, 200 m west of Lagoa Azul , rocky shore with coralline algae, crevices and under rocks, low tide, coll. A. Anker, N. Knowlton, 31.01.2006 [fcn 06-063A]; 1 male, OUMNH. ZC.2012-07-091, same collection data [fcn 06-093*] ; 1 male, 1 ov. female, RMNH D54831, same collection data [fcn 06-094*] ; 1 male, 1 female, RMNH D54835, same collection data [fcn 06-097*, 06-098]; 1 ov. female, RMNH D54834, same collection data [fcn 06-099*]; 1 ov. female, MNHN-IU-2010-4103, same collection data, specimen infested by a microsporidean parasite [fcn 06- 100*] ; 1 male, MNHN-IU-2010-4104, 2 km west of Lagoa Azul , near ship wreck, rocky shore with coralline algae, in crevices of rocks and coralline algae, low tide, coll. A. Anker, N. Knowlton, 01.02.2006 [fcn 06-121]; 1 male, RMNH D54833, Lagoa Azul, shallow bay with rocky shore, coralline algae and rocks, 1–3 m, A. Anker, N. Knowlton, 03.02.2006 [fcn 06-146*]; 1 male, 1 female, MNHN-IU-2010-4105, same collection data [fcn 06- 214*]; 1 ov. female, MNHN-IU-2010-4106, same collection data [fcn 06-215] ; 1 male, 1 female, OUMNH. ZC.2012-07-086, Ilha Santana , rock crevices, 15–20 m, coll. N. Knowlton, F. Nunes, 09.02.2006 [fcn 06- 210*]; 1 ov. female, OUMNH. ZC.2012-07-087, about 4 km west of Lagoa Azul , shallow subtidal, 0.5–2 m, under rocks, coll. A. Anker, 17.02.2006 [fcn 06-248]; 1 ov. female, OUMNH. ZC.2012-07-118, same collection data [fcn coll. N. Knowlton et al., 04.04.1998; 4 males, 2 ov. females, RMNH D54830, Santiago, Terrafal, coll. N. Knowlton et al., 03.04.1998; 2 males, 2 females, 1 ov. female, MNHN-IU-2010-4107, Santiago , Cidade Velha, coll. N. Knowlton et al., 02.04.1998.

Diagnosis. Rostrum slender, much longer than wide at base, usually longer than orbital hoods, cylindrical in cross-section, abruptly delimited posteriorly, with base distinctly rising above adjacent area of orbital hoods; orbital teeth acute, directed somewhat mesially; notches between orbital teeth and rostrum broad and deep. First abdominal somite in males acutely produced posteroventrally. Telson broad, tapering posteriorly, with lateral margin slightly concave in posterior half; 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 longer than wide; stylocerite sharp, its tip not reaching distal margin of second article. Antenna with basicerite armed with sharp distodorsal tooth and stout, sharp ventrolateral tooth, latter barely reaching distal margin of first article of antennular peduncle; scaphocerite with narrow blade; distolateral tooth reaching end of antennular peduncle but not overreaching carpocerite. Third maxilliped with crown of five to seven spiniform setae on tip of ultimate article. Major chela with palm less than twice as long as fingers; distal tooth rather small, flattened, blunt or subacute distally, sometimes reduced to small tubercle. Second pereiopod with carpus five-articulated, first article longer than sum of all others. Third pereiopod moderately slender, with merus at least four times as long as maximum width; propodus with about eight-nine 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 africanus .

Size range. Males, 3.9–5.9 mm cl; females, 4.8–6.7 mm cl.

Colour in life. General colour variable from pale greenish or greenish-pinkish to reddish and bluish-purplish, speckled tiny red chromatophores; chela distally much darker, with small white patch on distomesial portion of palm, near dactylo-propodal articulation; dactylus with a conspicuous, semicircular white patch adjacent to amberorange tip; ovaries and freshly laid eggs dark olive-green ( Figs 1 , 2 ).

Type locality. São Tomé .

Distribution. Eastern Atlantic: Mediterranean Sea: from Gibraltar to Israel; Morocco; Canary Islands; Cape Verde; Gulf of Guinea: Guinea, São Tomé and Principe, Annobón ( Crosnier & Forest 1966; d'Udekem d'Acoz 1999; Quiles et al. 2001; Bacci et al. 2010; present study; see map in Fig. 51 ).

Ecology. Shallow hard and mixed bottoms from the intertidal to at least 20 m ( Crosnier & Forest 1966; d'Udekem d'Acoz 1999; present study); in crevices of rocks and coralline algae, e.g., Mesophyllum lichenoides ; also among solitary corals, Dendrophyllia cornigera , and black corals, Antipathes sp. ( Lewinsohn & Holthuis 1964; Türkay 1982; García Raso & Fernández Muñoz 1988); typically in heterosexual pairs.

Remarks. Crosnier & Forest (1965, 1966) established two subspecies for what appears to be the eastern Atlantic representatives of the mainly Indo-West Pacific S. tumidomanus ( Paulson, 1875) complex: S. hululensis africanus Crosnier & Forest, 1965 and S. hululensis congoensis Crosnier & Forest, 1965 , which, because of the synonymy of S. hululensis Coutière, 1908 with S. tumidomanus later became S. tumidomanus africanus and S. tumidomanus congoensis , respectively. The differences between S. tumidomanus from the Red Sea (sensu Paulson 1875) and the two eastern Atlantic subspecies are subtle, but appear to be consistent ( Crosnier & Forest 1966). For instance, S. tumidomanus differs from the two Atlantic species by the more slender antennular peduncles, with the second article almost twice as long as wide, the distinctly longer scaphocerite (reaching the end of the carpocerite), and the narrower notches between the rostrum and orbital teeth ( Crosnier & Forest 1966: fig. 30). These differences, combined with the geographic separation between the eastern Atlantic and Indo- West Pacific populations, suggest that S. tumidomanus africanus and S. tumidomanus congoensis most likely represent two valid species and should be treated as S. africanus and S. congoensis , respectively (see also under S. congoensis below).

Most specimens of S. africanus from São Tomé agree well with the description of this species (as S. hululensis africanus ) provided by Crosnier & Forest (1966). However, two specimens from São Tomé as well as several specimens from the western Atlantic (Caribbean Sea and northeastern Brazil) appear to be different from the typical S. africanus and S. congoensis and are collectively treated below under S. cf. africanus .

integument ( Fig. 1B ). Microsporideans are also known from other alpheid shrimps. For instance, a species of the genus Thelohania (s. lat.) Henneguy, 1892 was reported from Athanas nitescens Leach, 1814 by Nouvel & Nouvel (1935). Several other microsporideans parasitise palaemonid shrimps, nephropid lobsters, parastacid crayfishes, and other decapods (e.g., Azevedo et al. 2000; Moodie et al. 2003a, 2003b; Stentiford et al. 2010).

(OUMNH.ZC.2012-07-118); g, ovigerous female (not deposited); h, ovigerous female (OUMNH.ZC.2012.07-085). Photographs a–g, by A. Anker; h, courtesy of N. Knowlton.

Figures

FIGURE 1. Synalpheus africanus Crosnier & Forest, 1965: two specimens from São Tomé; a, male (OUMNH.ZC.2012-07- 089); b, ovigerous female infested by a microsporodean parasite (MNHN-IU-2010-4103). Photographs by A. Anker.

FIGURE 2. Synalpheus africanus Crosnier & Forest, 1965: seven specimens from São Tomé (a-g) and one specimen from Cape Verde (h), showing variation in the general colour; a, female (OUMNH.ZC.2012-07-086); b, male (OUMNH.ZC.2012- 07-091); c, male (OUMNH.ZC.2012-07-086); d, female (RMNH D54831); e, male (RMNH D54833); f, ovigerous female

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