Alpheus cf. rostratus W. Kim & Abele, 1988

Almeida, Alexandre O., Boehs, Guisla, Araújo-Silva, Catarina L. & Bezerra, Luis Ernesto A., 2012, Shallow-water caridean shrimps from southern Bahia, Brazil, including the first record of Synalpheus ul (Ríos & Duffy, 2007) (Alpheidae) in the southwestern Atlantic Ocean, Zootaxa 3347, pp. 1-35 : 13

Alpheus cf. rostratus W. Kim & Abele, 1988

( Fig. 2 E)

Alpheus rostratus W. Kim & Abele, 1988: 51 , fig. 21.

Material examined. 1 m, 1 f, 01.VIII.2008, Cairú, Triana River, Boipeba Island, MZUESC 1271; 1 f, 03.VIII.2008, Cairú, Tassimirim Beach, Boipeba Island, MZUESC 1321; 6 m, 4 f, 1 juv, 16.V.2007, Santa Cruz Cabrália, Coroa Vermelha Beach, MZUESC 870.

Distribution. Alpheus cf. rostratus: Western Atlantic—Brazil (Bahia) (present study). Alpheus rostratus : Eastern Pacific—Gulf of California to Colombia ( Kim & Abele 1988; Ramos 1995).

Ecological notes. On coral reefs, in crevices of rocks and concretions of calcareous algae; also in estuaries (specimens found in palm tree roots on muddy bottom). Salinity range: 24–39 psu.

Previous records. None.

Remarks. This species is morphologically close to A. cf. paracrinitus but differs from it in the color pattern. Alpheus cf. rostratus has wide transverse bands on the carapace and abdomen and a pair of dark dorsal spots on the third abdominal somite (see Figs. 2 D and 2E for comparison). A similar color pattern exists in the eastern Pacific A. rostratus , which belongs to the A. paracrinitus complex (A. Anker, pers. comm.). Some minor morphological differences were noted between A. cf. rostratus and A. rostratus , based on the original description and figures ( Kim & Abele 1988). For example, A. cf. rostratus differs from A. rostratus by the more strongly produced distodorsal margin of the antepenultimate article of the third maxilliped. In A. cf. rostratus , the distolateral tooth of the scaphocerite extends slightly beyond the anterior margin of the blade, and the cleft between the blade and the tooth is approximately 1/3 of the total length of the scaphocerite. In cotrast, in A. rostratus , the distolateral tooth of the scaphocerite extends conspicuously beyond the anterior margin of the blade, and the cleft between the blade and the tooth slightly less than 1/2 of the total length of the scaphocerite. In A. rostratus , the tooth on the ventromesial carina of the antennular peduncle is concave, whereas in A. cf. rostratus , the anterior margin of this tooth is nearly straight. These differences, if shown to be valid and consistent, suggest that the Bahian material may belong to a new species close to A. rostratus . However, only a taxonomic revision of the entire A. paracrinitus complex will clarify the identity of A. cf. rostratus and A. cf. paracrinitus . Therefore, all records of A. paracrinitus from Brazil ( Christoffersen 1998) need to be treated with a lot of caution.

Figures

FIGURE 2. Alpheid shrimps from southern Bahia, Brazil. (A) Alpheus bouvieri A. Milne-Edwards, 1878, male from Cachoeira River, Maramata Beach, Ilhéus. (B) Alpheus cristulifrons Rathbun, 1900, ovigerous female from Tassimirim Beach, Cairú. (C) Alpheus formosus Gibbes, 1850, male from Tassimirim Beach, Cairú. (D) Alpheus cf. paracrinitus Miers, 1881, male from Taipus de Fora Beach, Maraú. (E) Alpheus cf. rostratus W. Kim & Abele, 1988, ovigerous female from Taipus de Fora Beach, Maraú. (F) Salmoneus carvachoi Anker, 2007, two ovigerous individuals from Maraú River, Maraú.