Automate cf. rectifrons Chace, 1972

Soledade, Guidomar O., Fonseca, Mytalle S. & Almeida, Alexandre O., 2015, Shallow-water stenopodidean and caridean shrimps from Abrolhos Archipelago, Brazil: new records and updated checklist, Zootaxa 3905 (1) : -

Automate cf. rectifrons Chace, 1972

( Fig. 3 F, 4)

Material examined. 1 n-ov, 02.ix.2013, Ilha de Santa Bárbara (17°57’49”S 38°41’53”W), coll. G.O. Soledade, intertidal, under rocks, UESC 1558.

Distribution. Western Atlantic—Mexico (Quintana Roo), possibly Antigua; Brazil (Bahia and São Paulo?) ( Chace 1972; Pires-Vanin et al. 1997; Anker & Komai 2004; this study).

Previous records from Abrolhos. None.

Remarks. Automate rectifrons was previously known with certainty only from the type locality, Quintana Roo, Mexico. Pires-Vanin et al. (1997) recorded this species from São Sebastião Channel, São Paulo, however, in a species list, i.e. without any morphological account; therefore, the record from São Paulo requires confirmation. The present specimen from the Abrolhos ( Fig. 4 A, B) is the first confirmed record of A. rectifrons in Brazil and the South Atlantic. Based on its morphological features (e.g., third and fourth pereiopods without stout spiniform setae; stylocerite not exceeding first article of the antennular peduncle), A. rectifrons belongs to the A. evermanni Rathbun, 1901 species group (see Anker & Komai 2004). The Abrolhos specimen differs from the holotype specimen of A. rectifrons (cf. Chace, 1972) in several characteristics. In the Abrolhos specimen, the major cheliped fingers are curved and have a broad gap and sharp teeth on the cutting edges (two on the dactylus and four on the pollex). In the holotype of A. rectifrons , the fingers are not curved, the gap between them is rather narrow, and the cutting edge of the pollex bears only one proximal tooth (cf. Chace 1972). Other divergent characters are the shape of the major cheliped merus (irregular and armed with a sharp tooth on the mesial margin ( Fig. 4 C) vs. semirectangular and unarmed on the mesial margin in Chace’s material) and the uropods (with endopod only slightly overreaching exopod ( Fig. 4 F) vs. strongly overreaching exopod in Chace’s material). It is noteworthy that the Abrolhos is similar in size to the holotype, at cl 3.0 mm and cl 3.5 mm, respectively. Thus, the above-noted differences between the Abrolhos specimen and the holotype may be of some taxonomic significance. However, more material needs to be collected in the Caribbean Sea and in Brazil to draw more definitive conclusion on the status of the Brazilian populations.

Figures

FIGURE 3. Some caridean (alpheid) shrimps from Ilha de Santa Bárbara, Abrolhos, Bahia, Brazil: A, Alpheopsis cf. trigona (Rathbun, 1901); B, Alpheus bouvieri A. Milne-Edwards, 1878; C, Alpheus carlae Anker, 2012; D, Alpheus formosus Gibbes, 1850; E, Alpheus verrilli (Schmitt, 1924); F, Automate cf. rectifrons Chace, 1972; G, Synalpheus cf. brevicarpus (Herrick, 1891); H, Synalpheus fritzmuelleri Coutière, 1909. Scale bars = 5 mm.

FIGURE 4. Automate cf. rectifrons Chace, 1972. Female from Ilha de Santa Bárbara, Abrolhos, Bahia, Brazil (UESC 1558). A, frontal region and cephalic appendages, dorsal view (setae omitted); B, same, lateral view (setae partially omitted); C, major cheliped, lateral view (setae omitted); D, same, detail of chela, lateral view; E, minor cheliped, lateral view; F, uropods and telson, dorsal view (setae partially omitted). Scale bars = 1 mm.