Alpheus mathewsae, 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 : 68-74
treatment provided by
Alpheus mathewsae sp. nov.
( Figures 49–53, 65I, 66I, 69D)
Alpheus armillatus (not H. Milne Edwards, 1837)—(?) Hendrix 1971: 59, 60 (part., blue-grey colour pattern).
Alpheus cf. armillatus H1, H2— Mathews & Anker 2009: 277.
Type material. Panama: holotype: male (cl 8.0), MNHN-IU-2010-4092 , Isla Grande, southern coast near Playa de la Punta, protected sand flat with abundant rubble, seagrass, on sand and silt under rocks, 0.5–1 m, leg. A. Anker, 22.04.2006 [fcn 06-409A]; paratypes: 1 ov. female (cl 7.7), MNHN-IU-2010-4093, same collection data as for the holotype [fcn 06-409B]; 1 male (cl 7.9), MNHN-IU-2010-4094 , Isla Grande, southern coast between village and Playa de la Punta, sand flat with abundant rubble and seagrass, on sand or silt under rocks, less than 1 m, leg. A. Anker, 21.04.2006 [fcn 06-407, dissected]; 1 ov. female (cl 8.2), RMNH D54823 View Materials , Bocas del Toro , Isla Carenero, near Bucaneer, shallow subtidal flat with abundant seagrass and coral rubble, 0.5–1.5 m, leg. A. Anker, 25.10.2005 [fcn 05-176]; 1 ov. female (cl 9.0), OUMNH. ZC. 2011-06-037, Bocas del Toro , Isla Bastimentos, near Bastimentos village , shallow sand flat near mangrove stands, under rocks in silt and sand, less than 1 m, leg. A. Anker, J.A. Vera Caripe, J.A. Baeza, 18.11.2006 [fcn 06-605]; 1 ov. female (cl 10.8), RMNH D54824 View Materials , Bocas del Toro , Isla Bastimentos, near Bastimentos village , shallow sand flat near mangrove stands, under rocks in silt and sand, less than 1 m, leg. A. Anker, 03.05.2007 [fcn 07-167]; 1 ov. female (cl 9.6), UP, Bocas del Toro, off Isla Colón, Boca del Drago , dredge, 20 m, J. Jara et al., 13.10.2007 [fcn 07-339]; 1 ov. female (cl 13.2), MNHN-IU-2010-4095, Bocas del Toro , Isla Colón, Boca del Drago , shallow sand flat with rocks and rubble near extensive seagrass beds, less than 1 m, leg. A. Anker, J.A. Vera Caripe, J.A. Baeza, 11.11.2006 [fcn 06-557] .
Additional material. USA: 1 ov. female (cl 11.9), MNHN-IU-2010-4096, Florida Keys , near Bahia Honda State Park, ocean side, shallow flat with abundant coral rubble, 1–1.5 m, under rocks and rubble, leg. A. Anker, 25.09.2007 [fcn 07-291]; 1 ov. female (cl 13.2), RMNH D54825 View Materials , Florida , Indian River Lagoon, Wabasso Lake, on muddy sand under rocks, 0.5 m or less at low tide, leg. A. Anker, A.L. Rhyne, 20.04.2004 [fcn 04-026]; 1 male (cl 9.5), 1 female (cl 10.3), RMNH D54826 View Materials , same collection data [fcn 04-025, female dissected] ; 3 males (cl 9.6–11.5), 1 ov. female (cl 10.2), RMNH D16986 View Materials , Florida , south of Marco, on the beach among debris after hurricane Donna, leg. L.B. Holthuis, 12.09.1960 ; 1 male (cl 12.8), FLMNH UF Arthropoda 15335, Florida , Tampa Bay , 3 km east of Sunshine Skyway Bridge, 27.631° -82.628°, spoil heap, Capetown dredge, 8–9 m, leg. G. Paulay, 06.02.2009 [fcn BFIO-024].
Diagnosis. Rostrum straight, usually reaching half-length of first article of antennular peduncle; area posterior to rostral carina flattened, markedly but not abruptly delimited from adjacent, shallow to moderately deep rostroorbital furrows, forming V-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 shoulder 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, proximal height about 0.6 length of distolateral margin, anterior angle smooth, more than 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, non-balaeniceps, with sharp cutting edges. Female minor cheliped generally similar to male minor cheliped, more slender; 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 each with subacute or blunt median processes, usually small on first and strongest on second and third sternite. 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 ( Figs. 49–51).
Size range. The type specimens from Panama range from 7.9 to 8.0 mm cl in males (holotype: 8.0 mm), and from 7.7 to 13.2 mm cl in females; Florida specimens range from 8.2 to 12.8 mm cl .
Colour pattern. Body uniform reddish-brown to dark brown, sometimes greyish-brown, with very narrow colourless bands on abdomen in adults, these bands being broader in younger individuals; second and fourth pleura with two pairs of conspicuous black spots laterally, one pair at about mid-length of second pleuron and one pair close to posterior margin of fourth pleuron; post-rostral plate with brown-red margins; antennular and antennal flagella pale brownish or greenish; chelipeds with ischium, merus and carpus whitish, distodorsally more brownish or brown-grey; mesial face of major chela olive-brown to orange-brown, without spots; dactylus and pollex pink 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-grey with pale areas proximally, exopod sometimes with bluish tinge distally and also with some golden-yellow chromatophores laterally; eggs olive-green ( Figs. 50, 51); compare with “blue-grey colour pattern” in Hendrix (1971, p. 65).
lina and appendix interna, lateral view; L, telson, dorsal view; M, uropod, dorsal view; N, rostro-orbital region of carapace, dorsal view; O, same, dorsolateral view; P, diagrammatic representation of first two abdominal sternites, ventroposterior view; Q, median process on second abdominal sternite of large ovigerous female, anterolateral view. Scale bars as indicated, figs. D, J, P drawn without scale.
Etymology. This species is named after Dr. Lauren Mathews (Worcester Polytechnic Institute) for her important studies on Alpheus armillatus , including two studies on phylogeography and molecular phylogeny ( Mathews 2006; Mathews & Anker 2009).
Type locality. Panama: Isla Grande and Bocas del Toro .
Distribution. Florida: Fort Pierce, Florida Keys, Marco, Tampa Bay; Caribbean Sea: Panama (Bocas del Toro, Isla Grande); Puerto Rico (Aguirre) (see map in Fig. 70).
Ecology. Intertidal and shallow subtidal habitats, typically protected bays and lagoons; typical depth range 0–3 m (although some specimens were collected much deeper, 8–20 m); on sand, sand-mud or silt bottoms, with abundance of large rocks and coral rubble, often close to mangroves or seagrass beds; usually under large rocks, coral rubble, algal clumps etc.; in male-female pairs.
the general shape of the post-rostral plate and major and minor chelipeds, A. mathewsae sp. nov. is indeed closest to A. angulosus and A. carlae sp. nov. On morphological grounds, A. mathewsae sp. nov. can be separated from A. angulosus by the major chela dactylus with a distinctly shorter, distally truncate plunger (cf. Figs. 20C, 50E, J; see also Fig. 65); the minor chela with the fingers slightly longer than palm and with a slightly less pronounced ventral sinus in males (cf. Figs. 20D, E, 50F, G); and the first to fourth abdominal sternites each bearing a strong, subacute median process in males (vs. with a small blunt median process on the first somite only, in A. angulosus ; cf. Figs. 19I, 49J). Alpheus mathewsae sp. nov. also differs morphologically from A. carlae sp. nov., mainly by the unarmed ischium of the fifth pereiopod (armed with a small spiniform seta or a trace of it in A. carlae sp. nov.) and the shorter plunger of the major chela dactylus (cf. Figs. 42D, 50E, J). For morphological differences between A. mathewsae sp. nov. and other species of the A. armillatus complex refer to Table 1.
In life, A. mathewsae sp. nov. can be easily distinguished from both A. angulosus and A. carlae sp. nov. by the colour pattern, for instance, from A. angulosus by the generally darker, more uniform brownish background colour, the presence of at least two pairs of black spots on the flanks of the abdominal somites, and the dorsal and ventral depressions of the major chela less conspicuously marked with a whitish patch (cf. Figs. 22–26 and 52, 53); from A. carlae sp. nov. by the less conspicuous banding of the abdominal somites, and by the major and minor chelae uniform green-brown, without whitish spots or blotches (cf. Figs. 44–48 and 52, 53); from both of them by the conspicuous bright orange colour on the mesial side of the plunger of the major chela dactylus ( Fig. 68; see also below).
The phylogenetic position of the Atol das Rocas specimen “ Alpheus cf. armillatus 35” as sister to A. mathewsae sp. nov. within Clade 3 ( Mathews & Anker 2009, fig. 4) remains unclear. This specimen has all the diagnostic features (including colour pattern) of A. angulosus from Clade 2 (see above).
GenBank accession numbers. Florida (East coast): DQ682884 View Materials (16S) , FJ528520 View Materials ( COI) [ RMNH D54825 View Materials ]; Florida Keys : FJ528560 View Materials (MyHC) , FJ528461 View Materials (16S) FJ528521 View Materials ( COI) [not deposited]; Puerto Rico : DQ682881 View Materials (16S) , FJ528526 View Materials ( COI) [not deposited]; Panama : FJ528459 View Materials (16S) , FJ528517 View Materials ( COI) .
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