Alpheus brasileiro, Anker, 2012

Anker, Arthur, 2012, Revision of the western Atlantic members of the Alpheus armillatus H. Milne Edwards, 1837 species complex (Decapoda, Alpheidae), with description of seven new species, Zootaxa 3386 (1), pp. 1-109 : 74-81

Alpheus brasileiro sp. nov.

( Figures 54 –56, 64I, 65J, 66J, 67H, 68A)

Type material. Brazil: holotype: 1 male (cl 10.9), MZUSP 25236 , Ceará, Praia de dois Coqueiros, rocky shore exposed at low tide, on sand under large rocks, leg. A. Anker, 24.05.2011 [fcn 11-008, partly dissected] ; paratypes: 1 female (cl 10.5), MZUSP 25237 , same collection data as for the holotype [fcn 11-009]; 1 male (cl 8.2), 1 female (cl 8.2), MNHN-IU-2010-4097, Ceará, Fortaleza, Meireles, rocky beach, under rocks in muddy sand, low tide, leg .

A. Anker, 16.05.2011 [fcn 11-007]; 1 male (cl 7.7), OUMNH. ZC. 2011-06-038, Ceará , Paracuru, Pedra Rachada beach, 03º25'S, 39º04'W, rocky intertidal, in tidal pool under rocks, leg. P. Pachelle, 16.04.2011 [fcn 11-004] ; 1 male (cl 6.6), RMNH D54827 , same collection data [fcn 11-005] ; 1 male (cl 9.7), OUMNH. ZC. 2011-06-039, Ceará , Fortaleza, Meireles beach, rocky intertidal, under rocks in muddy sand, low tide, leg. A. Anker, P. Pachelle, 16.06.2011 [fcn 11-067] ; 2 females (cl 7.3, 8.3), MNHN-IU-2010-4098, Ceará , Pacheco Beach, rocky intertidal, low tide, under rocks, leg. P. Pachelle, 19.06.2011 [fcn 11-070] ; 1 male (cl 7.7), Ceará, Camocim, Praia do Farol de Trapiá , OUMNH. ZC. 2012-07-024, sand-rock intertidal, low tide, under rocks, leg. P. Pachelle, 08.04.2012 [fcn 12-004]. view; B, non-type, ovigerous female from Bahia Honda , Florida Keys [MNHN-IU-2010-4096], lateral view; C, paratype, female from Bocas del Toro, Panama [ RMNH D54823 ], dorsal view; D, non-type, female from Indian River Lagoon , Florida [ RMNH D54825 ], dorsal view. Photographs: A–C, by the author; D, by the author / A.L. Rhyne .

Additional material. Brazil: 1 male (cl 6.8) , 2 females (cl 6.9, 7.7), 1 ov. female (cl 10.3), MZUSP 24820 , Alagoas, Barra de Camaragibe, Rio Camaragibe estuary, hand collecting at night, leg. M. Tavares, J.B. Mendonça, 28.10.2011 ; 1 male (cl 8.1), MZUSP 16697 , Para, Vila do Algodoal , 00°35'38''S 47°35'00''W, leg. E. Matis, 22.11.2004 ; 2 males (cl 11.0, 11.2), MZUSP 4858 , São Paulo, Cananéia, collector unknown, 02.02.1967 ; 1 male (cl 10.4), MZUSP 0195 , São Paulo, Iguape , leg. R. Krone, 1902 ; 1 male (cl 10.0), 1 ov. female (cl 8.5), MZUSP 5345 , Rio de Janeiro, Angra dos Reis, Praia do Tanguá , leg. G. S. de Melo, 20.07.1966 ; 2 ov. females (cl 10.3, 11.3), MZUSP 20130 , Santa Catarina, Praia da Ponta do Sambaqui , oyster culture ( Pteria hirudo ), leg. R. Alves, 07–09.2008 .

Diagnosis. Rostrum straight, reaching to about half-length of first article of antennular peduncle; area posterior to rostral carina flattened, markedly delimited from adjacent, fairly deep rostro-orbital furrows, forming V-shaped or V/U-shaped post-rostral plate continuous with narrow, dorsally blunt rostral carina, margins of post-rostral plate not overhanging rostro-orbital furrows; post-rostral plate situated at about the same level as rostral carina or slightly above it, in latter case gently sloping. Antennule with stylocerite acute distally, barely reaching distal margin of first article; ventromesial carina of first article with tooth bearing small subacute point above concave anterior margin; second article about twice as long as wide. Antenna with basicerite armed with stout, sharp distolateral tooth; scaphocerite with broadly concave lateral margin, strong distolateral tooth reaching far beyond moderately broad blade; carpocerite exceeding scaphocerite blade and sometimes distolateral tooth, reaching past end of antennular peduncles. Third maxilliped with ultimate article as broad as penultimate, tapering distally. Major cheliped edwardsii - type (see under A. armillatus ). Male major cheliped with merus stout, distodorsal margin ending bluntly, ventromesial margin smooth, without spiniform setae, with strong, sharp distomesial tooth; palm with dorsal shoul- der rounded, sloping obliquely into adjacent transverse groove, not overhanging groove; ventral shoulder broadly rounded, not projecting, smooth laterally; fingers more than half-length of palm; pollex without ridge mesially; dactylus plunger moderately large, stout, broad, proximal height at most 0.6 length of distolateral margin, anterior angle almost 90°. Female major cheliped usually smaller than male major cheliped, with chela smaller and with more or less different proportions. Male minor cheliped with merus moderately stout, distodorsal margin blunt, ventromesial margin without spiniform setae, with small distomesial tooth; chela moderately slender, palm with length-height ratio about 2.0; palm with very slight longitudinal depression laterally and slight sinus ventrally, latter not distinctly delimited by ventral shoulder; fingers usually slightly longer than palm, slender, simple, nonbalaeniceps, with sharp cutting edges. Female minor cheliped generally similar to male minor cheliped, more slen- der; palm without or with very slight ventral sinus. Second pereiopod slender, with first two carpal articles longest, first about 1.4 length of second. Third and fourth pereiopods similar, rather slender; ischium with stout spiniform seta ventrolaterally; merus about five times as long as wide; propodus with stout spiniform setae, sometimes inserted in pairs, along ventral margin, incuding one pair adjacent to dactylus; dactylus at least 0.4 length of propodus, simple, conical. Fifth pereiopod much more slender than third and fourth; ischium unarmed in both sexes. Sternum at the base of fourth pereiopods without conspicuously projecting, slender, subacute processes. First to fourth abdominal sternites in males each with median process between bases of pleopods, processes stronger on first and second sternites, weaker and blunter on third and fourth sternites; first to fourth sternites in females unarmed. First to fourth pleopods without spiniform setae on ventrolateral margin of protopod in both sexes; male second pleopod with appendix masculina somewhat shorter than appendix interna, densely covered with stiff setae apically and mesially. Uropod with exopod and endopod broadly rounded; exopod with sinuous diaeresis and stout distolateral spiniform seta; endopod with row of small spiniform setae on distal margin. Telson broad, slightly tapering posteriorly; dorsal surface with two pairs of spiniform setae inserted far from lateral margins; posterior margin broadly rounded, with row of small spiniform setae; posterolateral angles each with two stouter spiniform setae, mesial much longer than lateral ( Fig. 54 ).

Size range. The type specimens range from 6.6 to 10.9 mm cl in males (holotype: 10.9 mm), and from 7.3 to 10.5 mm cl in females.

Colour pattern. Body background ranging from pale brown to dark brown or olive-brown; abdomen with narrow colourless bands in adults becoming wider posteriorly, white dorsal areas of three posterior somites speckled with tiny yellow chromatophores; second, third and fourth pleura with three pairs of black spots: one pair of larger spots laterally at about mid-length of second pleuron, one pair of smaller spots dorsolaterally at about mid-length of third pleuron, and one pair of larger spots laterally near posterior margin of fourth pleuron; post-rostral plate beige or grey areas, without spots; dactylus and pollex pinkish distally, dactylus plunger bright orange mesially; mesial face of minor chela olive-brown; second to fifth pereiopods pinkish or reddish; telson and uropods mostly brownish or brown-green with pale areas proximally, exopod with some golden-yellow chromatophores laterally; eggs dirty-yellow to yellow-greenish (Figs. 55, 56C), abdominal spots occasionally missing on one or both sides, e.g., in some younger individuals (Fig. 56A).

Etymology. The new species name is the Portuguese word for the inhabitants of Brazil, to which it appears to be endemic; used as a noun in apposition.

Type locality. Brazil: Ceará: Fortaleza area (Meireles, Praia de dois Coqueiros) and Camocim .

Distribution. Brazil: Ceará, Rio Grande do Norte (P.P.G. Pachelle, pers. comm.), Alagoas, Bahia (based on colour photographs of A. O. de Almeida), Rio de Janeiro, São Paulo, Santa Catarina.

Ecology. Rocky and mixed rocky-sandy intertidal areas, usually in the relatively protected shore-side portion of exposed rocky reefs, with large tide pools among rocks; typically under large rocks in muddy sand, also in sabellariid reefs; in male-female pairs.

Remarks. Alpheus brasileiro sp. nov. is closely related to the previous species, A. mathewsae sp. nov. The only significant morphological differences between these two forms appear to be the absence of median processes on abdominal sternites in females of A. brasileiro sp. nov. (vs. present and usually very strong in A. mathewsae sp. nov., cf. Fig. 49P, Q ), and the major chela with a larger, broader, anteriorly more angular dactylus plunger in A. brasileiro sp. nov. compared to that of A. mathewsae sp. nov. (cf. Figs. 50E, J , 54K ; see also Fig. 65 ), a feature most obvious in adult males.

The colour pattern of A. brasileiro sp. nov. (Figs. 55, 56) is generally very similar to that of A. mathewsae sp. nov. ( Figs. 52 , 53 ), especially im the general brownish colour, the non-spotted major and minor chelae, the presence of two black lateral spots on the second and fourth pleura, and the bright orange colour on the mesial side of the plunger of the major chela dactylus ( Fig. 67A ). However, in adult specimens of A. brasileiro sp. nov., there is an additonal pair of very small, more dorsal spots on the third pleuron (Figs. 55A, 56B); these spots are absent in both adults and juveniles of A. mathewsae sp. nov..

Alpheus brasileiro sp. nov., known only from Brazil, appears to be geographically separated from A. mathewsae sp. nov., which is distributed more widely in southern Florida and throughout the Caribbean Sea (see maps in Fig. 70 ). However, more material from Guyana and Suriname, as well as northern parts of Brazil (e.g., Pará, Maranhão, Fernando do Noronha, Atol das Rocas) needs to be examined morphologically and genetically to determine the geographic range of A. brasileiro sp. nov., A preliminary COI comparison between A. brasileiro sp. nov. from Ceará and A. mathewsae sp. nov. from Panama and Florida revealed a clear genetic difference between these two taxa (C. Hurt, pers. comm.). Experiments on reproductive compatibility similar to those in Knowlton et al. (1993) for several transisthmian species pairs of Alpheus may provide additional evidence for their divergence.

GenBank accession numbers. Brazil (Ceará): JX135094 , JX135095 ( COI) [ MZUSP 25236 , 25237 ] .

Figures

FIGURE 49. Alpheus mathewsae sp. nov.: A–M, paratype, male from Isla Grande, Panama [MNHN-IU-2010-4094]; N–P, paratype, ovigerous female from Bocas del Toro, Panama [RMNH D54824]; Q, paratype, ovigerous frmales from Bocas del Toro [MNHN-IU-2010- 4093]; A, frontal region of carapace and frontal appendages, dorsal view; B, rostro-orbital region of carapace, lateral view; C, same, dorsolateral view; D, tooth on mesioventral carina of first article of antennular peduncle, lateral view; E, antennal scaphocerite, dorsal view; F, second pereiopod, lateral view; G, third pereiopod, lateral view; H, fifth pereiopod, lateral view; I, same, propodus and dactylus, ventral view; J, diagrammatic representation of first two abdominal sternites, ventroposterior view; K, second pleopod, detail of appendix mascu-

FIGURE 50. Alpheus mathewsae sp. nov.: A–H, paratype, male from Isla Grande, Panama [MNHN-IU-2010-4094]; I, J, holotype, male from Isla Grande [MNHN-IU-2010-4092); K, paratype, ovigerous female from Bocas del Toro, Panama [OUMNH ZC. 2011-06- 037]; A, major chela, lateral view; B, same, detail of dorsal shoulder, lateral view; C, major chela, mesial view; D, major cheliped, ischium, merus and carpus, mesial view; E, major chela dactylus, lateral view; F, minor chela, lateral view; G, same, meisal view; H, minor cheliped, ischium, merus and carpus, mesial view; I, major chela with dactylus open, lateral view; J, major chela dactylus, lateral view; K, major chela, lateral view. Scale bars as indicated.

FIGURE 52. Alpheus mathewsae sp. nov.: holotype, male from Isla Grande [MNHN-IU-2010-4092], dorsal (A) and lateral (B) views. Photographs by the author.

FIGURE 53. Alpheus mathewsae sp. nov.: A, paratype, ovigerous female from Bocas del Toro, Panama [RMNH D54824], dorsal

FIGURE 54. Alpheus brasileiro sp. nov.: A–G, holotype, male from Ceará, Brazil [MZUSP 25236]; H–J, paratype, male from Ceará [OUMNH.ZC. 2011-06-039]; K, paratype, male from Ceará [MNHN-IU-2010-4097]; L, paratype, female from Ceará [MNHN-IU- 2010-4097]; A, rostro-orbital of carapace, dorsal view; B, major chela, mesial view; C, minor chela, mesial view; D, second pereio-

FIGURE 65. Comparison of dactylus plungers of the major chela (in lateral view) among 12 western Atlantic species of the Alpheus armillatus H. Milne Edwards, 1837 complex and the related A. viridari (Armstrong, 1949); A–J, L, males; K, female; A, A. armillatus H. Milne Edwards, 1837; B, A. lancirostris Rankin, 1900; C, A. verrilli (Schmitt, 1924); D, A. angulosus McClure, 2002; E, A. amarillo sp. nov.; F, A. punctatus sp. nov.; G, A. tampensis sp. nov.; H, A. carlae sp. nov.; I, A. mathewsae sp. nov.; J, A. brasileiro sp. nov.; K, A. nuno sp. nov.; A. viridari (Armstrong, 1949). C, E, F, G, I, J mirrored horizontally from the originals for better visual comparison.

FIGURE 67. Frontal regions of nine western Atlantic species of the Alpheus armillatus H. Milne Edwards, 1837 complex, showing

FIGURE 70. Preliminary distribution maps for 11 western Atlantic species of the Alpheus armillatus H. Milne Edwards, 1837 complex (A. armillatus H. Milne Edwards, 1837; A. lancirostris Rankin, 1900; A. verrilli (Schmitt, 1924); A. angulosus McClure, 2002; A. amarillo sp. nov.; A. punctatus sp. nov.; A. tampensis sp. nov.; A. carlae sp. nov.; A. mathewsae sp. nov.; A. brasileiro sp. nov.; A. nuno sp. nov.) and A. viridari (Armstrong, 1949); individual locations refer to material reported in this study, verified literature records and in situ colour photographs.