Alpheus amblyonyx Chace, 1972 sensu

Anker, Arthur, Tavares, Marcos & Mendonça, Joel B., 2016, Alpheid shrimps (Decapoda: Caridea) of the Trindade & Martin Vaz Archipelago, off Brazil, with new records, description of a new species of Synalpheus and remarks on zoogeographical patterns in the oceanic islands of the tropical southern Atlantic, Zootaxa 4138 (1), pp. 1-58 : 14-15

Alpheus amblyonyx Chace, 1972 sensu lato

( Fig. 2 )

Alpheus amblyonyx Chace 1972: 59 , fig. 16; Pequegnat & Ray 1974: 245, fig. 49b; Christoffersen 1979: 302, fig. 1; Gore 1981: 151; Lemaitre 1984: 426; Rodríguez 1986: 130, fig. 31; Abele & Kim 1986: 197, 208, 209, figs. b–d; Martínez-Iglesias et al. 1997: 403, fig. 2; Christoffersen 1998: 356; McClure 2005: 125, fig. 3; Serejo et al. 2007: 198, text. fig.; Alves et al. 2008: 48; Souza et al. 2011: 46; Soledade & Almeida 2013: 94.

Alpheus cf. amblyonyx — Reed et al. 1982: 769; Williams 1988: 67, 71.

Alpheus macrocheles — Rathbun 1901: 105; Zimmer 1913: 386, fig. F (not A. macrocheles (Hailstone, 1835)) .

Crangon macrocheles — Schmitt 1935:142 (not A. macrocheles (Hailstone, 1835)) .

Material examined. Brazil: 1 ovig. female, MZUSP 30317, Trindade Island, Ilha da Racha, 20°30’26.5”S – 29°20’40.0”W, depth: 32 m, under rocks, coll. T. Simon, 30.i.2012; 1 ovig. female, MZUSP 33262, Trindade Island, Ilha da Racha, 20°30’26.5”S – 29°20’40.0”W, depth: 25 m, under rocks, coll. J.B. Mendonça, 12.xi.2014; 1 juvenile, MZUSP 30257, Trindade Island, Ponta do Monumento, 20°30’10.3”S – 29°20’36.1”W, depth: 12.1 m, coll. J.B. Mendonça, 16.vi.2012. Size of largest female: cl 5.0 mm ( MZUSP 33262).

Additional (extra-limital) material examined. Mexico: 1 male, OUMNH.ZC. 2016.02.0 34, Cozumel Island, about 1 km north of Playa Corona, coral rubble flat near fossilised platform wall, depth: 2 m, in dead conch shell, coll. A. Anker & J. Duarte, 08.vii.2010 (fcn COZ2-006).

Description. See Chace (1972) for detailed original description and illustrations; see also Christoffersen (1979) for additional figures and Anker & De Grave (2012a) for colour photographs (see also Fig. 2 ).

Distribution. Western Atlantic: Gulf of Mexico; Florida; off Maryland (including some problematic records, see below); throughout Caribbean Sea; Brazil: Ceará to Espírito Santo, North Chain Seamounts, Fernando de Noronha, Atol das Rocas , Vitória-Trindade Seamount Chain, Trindade & Martin Vaz Archipelago ( Chace 1972; Gore 1981; Williams 1988; Christoffersen 1998; Serejo et al. 2006, 2007; Soledade & Almeida 2013 and references therein; present study).

Ecology. Shallow and deeper subtidal coral reefs and associated habitats (e.g. seagrass beds) with abundance of coral rubble; typically in or under coral rubble, also in crevices of coralline algae; depth range: 0–24 m, exceptionally down to 145 m ( Gore 1981, but see below).

Remarks. Alpheus amblyonyx was previously reported from Trindade Island and Vitória-Trindade Seamount Chain by Serejo et al. (2007), and is also known from Atol das Rocas and the continental coast of Brazil ( Serejo et al. 2006; Soledade & Almeida 2013 and references therein). Alpheus amblyonyx is closely related to A. macrocheles ( Hailstone 1835) , a species widely distributed in the eastern and central Atlantic ( De Grave et al. 2014). All records of A. macrocheles from Brazil (e.g., Ramos-Porto 1979) are problematic as they may refer to A. amblyonyx ( Christoffersen 1998) or yet another, possibly undescribed taxon in the A. macrocheles species complex. Therefore, all Brazilian material identified as A. amblyonyx (including present material) or A. macrocheles will require a thorough comparison (morphology, colour patterns, DNA) with the Caribbean material of A. amblyonyx , as well as with A. macrocheles . It can be already noted that the colour pattern of the ovigerous female from Trindade Island ( Fig. 2 ) differs in some details from that of the Caribbean specimens of A. amblyonyx (see Anker & De Grave 2012a: fig. 4C, D), for instance, in the presence of white narrow transverse bands delimiting pleonites and short aligned streaks on the pleura and flanks of the carapace. For this reason, the present material was referred to as A. amblyonyx sensu lato.

Along the same lines, all records of A. amblyonyx from deeper water (below 70 m) need to be re-examined. These records include several mysterious specimens collected off central-eastern Florida that “appear to be more closely allied to A. macrocheles ” (see Gore 1981, under A. amblyonyx ); a specimen identified as A. cf. amblyonyx from a deep-water (80 m) coral reef of Oculina varicosa Lesueur , also off eastern Florida ( Reed et al. 1982); and especially “three lots of specimens” that “key out to A. amblyonyx but … differ in several respects from it”, from off eastern Florida and Veatch Canyon off Maryland, USA, tentatively reported as A. cf. amblyonyx by Williams (1988).

Figures

FIGURE 2. Alpheus amblyonyx Chace, 1972 sensu lato, ovigerous female from Ilha da Racha, Trindade Island, Brazil (MZUSP 33262): A — dorsal view; B — lateral view. Photographs by J. B. Mendonça.