Alpheus amarillo, 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 : 42-49

Alpheus amarillo sp. nov.

( Figures 27– 32 , 64E , 65E , 66B , 67E , 68B , 69C )

Alpheus cf. armillatus C— Mathews & Anker 2009: 277.

Type material. Panama: holotype: male (cl 8.5), MNHN-IU-2010-4081, Portobelo Bay , Isla Drake, near reef slope, fine sand with large pieces of rubble, 10-11 m, under rubble, leg. A. Anker, D. Roche, 21.07.2007 [fcn 07- 211, dissected]; paratypes: 1 female (cl 6.8), MNHN-IU-2010-4082, same collection data as for the holotype [fcn 07-209]; 1 male (cl 6.4), UP, same collection data as for the holotype [fcn 07-210]; 1 male (cl 11.0), RMNH D54800, San Blas Islands , Isla Diablo (small uninhabited island near Cartí), reef flat with rubble, 2–3 m, under rubble, A. Anker, I.N. Marin, 22.05.2007 [fcn 07-182]; 1 ov. female (cl 9.7), RMNH D54801, same collection data [fcn 07-183]; 1 ov. female (cl 9.1), MNHN-IU-2010-4083, same collection data [fcn 07-184] .

Additional material. Mexico: 1 ov. female (cl 9.3), MNHN-IU-2010-4084, Yucatan, Quintana Roo , Isla Cozumel, west coast, 1 km north of Playa Corona, off rugged shore platform (fossilesed coral), mostly hard bottom, next to wall, in dead conch, 2–3 m, leg. J. Duarte-Gutiérrez, 10.07.2010 [fcn COZ5-001 ]; 1 male (cl 13.0), UNAM-CNCR 26483, southern Gulf of Mexico off Yucatan, Arrecife Alacranes, sta. ALN39, “La Anegada” abundant rocks and coral rubble, 2 m, leg. J. Duarte-Gutiérrez, 11.08.2009 [fcn JD-058]; 1 ov. female (cl 14.5), UNAM- CNCR 26484 , southern Gulf of Mexico off Yucatan, Arrecife Alacranes , Anegada, station 16, in crevice under large rock, 6–8 m, leg. N. Simões et al., 14.06.2008 [fcn 08-246 = ALA107 ] . Belize: 1 ov. female (cl 11.4), OUMNH. ZC. 2009-01-0019, Carrie Bow Cay , patch reef adjacent to marine station, 16°48.346' N 88°04.928'W, from rubble, 5 m, leg. S. De Grave et al., 19.02.2009 . Honduras: 1 ov. female (cl 8.4), OUMNH. ZC. 2007-20- 0020, Utila, west of Ragged Cay, 16°05.294'N 086°59.844'W, gentle slope with fine sand and rubble, 10 m, under rubble, leg. A. Anker, S. De Grave, 04.07.2007 [fcn H139]; 1 female (cl 11.9), OUMNH. ZC. 2007-20-0021, Utila , Little Bight , 16°04.757'N 086°55.757'W, gentle slope with fine sand and rubble, 10 m, under rubble, leg. A. Anker, S. De Grave, 07.07.2007 [fcn H222]; 1 female (cl 10.2), OUMNH. ZC. 2007-20-0034, same collection data [fcn H223]; 1 ov. female (cl 6.2), OUMNH. ZC. 2007-20.0055, Utila , Black Coral Wall , 16°05.027'N 086°54.944'W, rubble field, ~ 30 m, from rubble, leg. S. De Grave, A. Anker, 04.07.2007 [fcn H153] . British Virgin Islands: 1 male (cl ~8.0), LACM (number to be assigned), Guana Island, Bigelow Beach, ~ 18.468°N ~ 64.565°W, sta. BVI- 00-045C, moderately open reef flat with medium-sized eroded coral heads with sponges and soft corals, benthos mostly sand and some Acropora cervicornis rubble, ARMS-05 rubble basket (mostly pieces of old Acropora palmata ), 9 m, leg. T. Zimmerman, G. Hendler, R. Ware, J.W. Martin, 11.07.2000 [fcn vc0550]; 1 female (cl ~9.0), LACM (number to be assigned), Guana Island , same collection data [fcn vc0833] . St. Martin: 1 female (cl 11.4), FLMNH UF Arthropoda 30328, Réserve Naturelle de Saint-Martin, sta. 40, Circus dive site off Tintamarre Island, coral reef, under large coral debris on silt-sand bottom, 13–17 m, leg. A. Anker, J.F. Maréchal, 19.04.2012 [fcn BSTM-1137]; 1 male (cl 9.6), FLMNH UF Arthropoda 30329, Réserve Naturelle de Saint-Martin, sta. 44, off Rocher Créole, 3–4 m, night dive, in silt and sand under large rocks, leg. A. Anker, J.F. Maréchal, 19.04.2012 [fcn BSTM-1304]; 1 male (cl 10.2), FLMNH UF Arthropoda 30330, Réserve Naturelle de Saint-Martin, sta. 16, Chicot, windward side of Tintamarre Island , coral reef, under coral rubble, 13–15 m, leg. G. Paulay et al., 12.04.2012 [fcn BSTM-0386] .

Diagnosis. Rostrum straight or slightly descendent, usually reaching half-length of first article of antennular peduncle; area posterior to rostral carina flattened, markedly and abruptly delimited from adjacent, deep rostroorbital furrows, forming more or less V or lance-shaped post-rostral plate continuous with dorsally slightly flattened rostral carina of various width, margins of post-rostral plate distinctly overhanging rostro-orbital furrows; post-rostral plate situated slightly above and gently sloping into rostral carina. Antennule with sctylocerite acute distally, barely reaching distal margin of first article; ventromesial carina of first article with large tooth bearing small acute point and concave anterior margin; second article about 2.5 times as long as wide. Antenna with basicerite armed with stout distolateral tooth; scaphocerite with lateral margin shallowly concave; strong, sharp distolateral tooth reaching slightly beyond relatively narrow blade; carpocerite exceeding scaphocerite blade and (very slightly) distolateral tooth, reaching beyond end of antennular peduncles. Third maxilliped with ultimate article somewhat more slender than penultimate, tapering distally. Major cheliped edwardsii - type (see under A. armillatus ). Male major cheliped with merus stout, distodorsal margin blunt, ventromesial margin more or less rugose, with short protuberances each carrying a small spiniform seta, distomesial tooth strong; palm with dorsal shoulder rounded, descending almost vertically into adjacent transverse groove, not or very slightly overhanging groove; ventral shoulder broadly rounded, not projecting, with field of minute tubercles laterally; fingers about 0.7 length of palm; pollex with short oblique ridge mesially; dactylus plunger short, truncate distally, proximal height about 0.3 length of distolateral margin, latter continuous with ventral margin of dactylus. Female major cheliped smaller than male major cheliped, with chela smaller, less stout, and with different proportions. Male minor cheliped with merus relatively slender, distodorsal margin blunt, ventromesial margin with small spiniform setae and strong distomesial tooth; chela relatively slender, palm with length-height about 2.5; palm with trace of longitudinal grooves on lateral and mesal faces, with weak ventral sinus; fingers about as long palm, slender, simple, non-balaeniceps, with sharp cutting edges. Female minor cheliped generally similar to male minor cheliped, usually smaller, more slender, and without ventral sinus. Second pereiopod slender, with first two carpal articles longest, first about 1.3 length of second. Third and fourth pereiopods similar, moderately slender; ischium with stout spiniform seta; merus slightly more than six times as long as wide; propodus with stout spiniform setae, some inserted in pairs, along ventral margin, incuding one pair adjacent to dactylus; dactylus slightly more than 0.4 length of propodus. Fifth pereiopod much more slender than third and fourth; ischium with stout spiniform seta in males, with small spiniform seta or at least a trace of it in females. Sternum at the base of fourth pereiopods without conspicuously projecting, slender, subacute processes. First and second abdominal sternites with short subacute or rounded median process in both sexes. First to fourth pleopods with ventrolateral margin of protopod sparsely furnished with spiniform setae in both sexes, more in females; male second pleopod with appendix masculina not exceeding 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 spiniform setae, mesial much longer than lateral ( Figs. 27 , 28 ).

Variation. Alpheus amarillo sp. nov. shows a particularly pronounced sexual dimorphism in the size and proportions of the major cheliped ( Fig. 28B, L ; see also Figs. 29 , 30). There is also a remarkable variation in the postrostral area, especially in the width of the rostral carina, which appears to be distictly broader in some larger individuals ( Fig. 27A, O, Q ). The short ridge on the major chela pollex appears to be more pronounced in larger individuals ( Fig. 28K ). In full-grown males of A. amarillo sp. nov., the minor chela palm shows traces of longitudinal grooves on both lateral and mesial surfaces and a shallow ventral sinus ( Fig. 28I ). The armature of the ischium of the fifth pereiopod appears to be somewhat variable in females, which are sometimes lacking a spiniform seta, although a trace of it is usually observable in its usual place, appearing as a small spine inserted deep under the cuticle ( Fig. 27R ). Most specimens have median processes on the first and second abdominal sternites. However, one adult female from St. Martin (FLMNH UF Arthropoda 30328) has and additional, fairly strong, median process on the third abdominal sternite.

Size range. The type specimens from Panama range from 6.4 to 11.0 mm cl in males (holotype: 8.5 mm), and from 6.8 to 9.7 mm cl in females; the largest specimens in the present series are 13.0 mm cl male and 14.5 mm cl female from Alacranes Reef, Gulf of Mexico .

Colour pattern. Body orange-yellow speckled with small pale-yellow spots, many interconnecting and forming long or branching chains; margins of post-rostral plate golden-yellow; antennular and antennal flagella orangeyellow; chelipeds with yellowish ischium, merus and carpus; mesial face of palm of major chela intense yelloworange, with conspicuous pink-purple areas, especially along longitudinal groove and near dactylar articulation; pollex yellow proximally, purplish distally; dactylus purple with pink, and whitish tip; in largest males, entire major chela entirely pale purple mesially, with some whitish areas and yellowish tinge; mesial face of palm of minor chela yellow with some bright purple on palm near articulation with dactylus, fingers yellow proximally, purple distally; second to fifth pereiopods yellowish, with whitish areas near articulations; telson patterned as abdomen; uropods pale yellow; yellow and purple colour usually more intense in situ; eggs bright yellow ( Figs. 29–32 ); juveniles lemon-yellowish, with darker chelae ( Fig. 69C ).

Etymology. From the Spanish word amarillo (yellow), referring to the bright yellow body colour of living shrimps; used as a noun in apposition.

Type locality. Caribbean coast of Panama: Portobelo and San Blas Islands .

Islands (Guana), Honduras (Utila), Belize (Carrie Bow Cay), Mexico (Cozumel); southwestern Gulf of Mexico: off Yucatan (Alacranes Reef); southern Florida (off Boca Raton / Delray Beach); records from Florida and St. Vincent based on underwater photographs ( Figs. 31C , 32 ) (see map in Fig. 70 ).

Ecology. Shallow to moderately deep coral reef habitats and adjacent rubble flats at a depth range of 2–30 m;

Remarks. Alpheus amarillo sp. nov. belongs to Clade 1 of Mathews & Anker (2009, fig. 4) and can be distinguished from all other species of the A. armillatus complex by a combination of morphological characters (see Table 1 and below) and a very diagnostic and conspicuous colour pattern ( Figs. 29–32 , corresponding to the colour type NB 1 in Mathews & Anker (2009, fig. 2A).

Using only morphological characters, A. amarillo sp. nov. may be separated from the four previously described species, viz. A. armillatus , A. verrilli (Clade 5), A. lancirostris (Clade 6) and A. angulosus (Clade 2), by the much shorter dactylus plunger and relatively more slender minor chela; from A. armillatus and A. verrilli by the more lance or V-shaped post-ros-

tral plate, more gently sloping into the rostral carina (more U-shaped and more markedly sloping in A. armillatus and A. verrilli ); from both A. lancirostris and A. angulosus by the ischium of the fifth pereiopod armed with a small spiniform seta in males and usually also in females (unarmed in both sexes in A. lancirostris and A. angulosus ); specifically from A. lancirostris by the acutely pointing tooth of the ventromesial carina of the first antennular article (blunt in A. lancirostris ), and the armature on the first two abdominal sternites (unarmed in A. lancirostris ); and specifically from A. angulosus by the lateral margins of the post-rostral plate abruptly delimited, clearly overhanging the adjacent deep rostro-orbital furrows (vs. gently delimited and not overhanging much shallower adrostral furrows in A. angulosus ). The dactylus plunger of A. amarillo sp. nov. is in fact the shortest of any western Atlantic species of the A. armillatus complex (Table 1; see also Fig. 65 ).

The above-reported morphological variation in A. amarillo sp. nov. and marked differences in COI and 16S sequences between the Honduran and the Panamanian specimens (as A. cf. armillatus 3 and 4, respectively, in Mathews & Anker 2009, fig. 4) suggest a rather strong genetic structure in populations of A. amarillo sp. nov., inviting a more detailed molecular analyses in this taxon.

GenBank accession numbers. Honduras: FJ528568 (MyHC) , FJ528441 (16S) , FJ528485 ( COI) [not deposited] ; Panama: FJ528569 (MyHC) , FJ528442 (16S) , FJ528486 ( COI) [ RMNH D54801] .

tographs by K. Wilk.

Figures

FIGURE 27. Alpheus amarillo sp. nov.: A–N, holotype, male from Portobelo, Panama [MNHN-IU-2010-4081]; O, P, paratype, ovigerous female from San Blas Islands, Panama [MNHN-IU-2010-4083]; Q, non-type, male from Alacranes Reef, Gulf of Mexico [UNAM-CNCR 26483]; R, non-type, ovigerous female from Alacranes Reef [UNAM-CNCR 26484]; 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, same, propodus and dactylus, lateral view; I, fifth pereiopod, lateral view; J, same, propodus and dactylus, lateral view; K, diagrammatic representation of first two abdominal sternites, ventroposterior view; L, second pleopod,

FIGURE 28. Alpheus amarillo sp. nov.: A–J, holotype, male from Portobelo, Panama [MNHN-IU-2010-4081]; K, paratype, male from San Blas Islands, Panama [RMNH D54800]; L–N, paratype, ovigerous female from San Blas Islands [MNHN-IU-2010-4083]; O, P, non-type, male from Alacranes Reef, Gulf of Mexico [UNAM-CNCR 26483]; A, major chela, mesial view; B, same, lateral view; C, same, detail of ventral shoulder, lateral view; D, same, detail of dorsal shoulder, lateral view; E, major chela dactylus, lateral view; F, major cheliped, ischium, merus and carpus, mesial view; G, same, detail of ventromesial margin, mesial view; H, minor chela and carpus, mesial view; I, minor chela, lateral view; J, minor cheliped, ischium, merus and carpus, mesial view; K, major chela, mesial view; L, major chela, lateral view; M, same, detail of dorsal shoulder, lateral view; N, same, detail of ventral shoulder, lateral view; O, major chela, lateral view; P, same, detail of dorsal shoulder, lateral view. Scale bars as indicated.

FIGURE 29. Alpheus amarillo sp. nov.: A, holotype, male from Portobelo, Panama [MNHN-IU-2010-4081], dorsal view; B, paratype, ovigerous female from San Blas Islands, Panama [MNHN-IU-2010-4083], dorsal view. Photographs by the author.

FIGURE 31. Alpheus amarillo sp. nov.: A, B, non-type, male from Guana Island, British Virgin Islands [LACM], dorsal (A) and lateral (B) views; C, female in situ, depth ~4 m, night dive in Lake Worth, Florida [specimen not collected]; D, male in situ, off Boca Raton, Florida [specimen not collected]. Photographs: A, B, by T.L. Zimmerman / J.W. Martin; C, D, by L. Ianniello.

FIGURE 32. Alpheus amarillo sp. nov.: A, B, ovigerous female in situ, Saint-Vincent, Lesser Antilles [specimen not collected]. Pho-

FIGURE 64. Comparison of proportions of the major chela (in lateral view) among 10 western Atlantic species of the Alpheus armillatus H. Milne Edwards, 1837 complex; A–I, males; J, 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. brasileiro sp. nov.; J, A. nuno sp. nov. Abbreviations: FB, finger base height; FH, fixed finger (pollex) height; FL, fixed finger (pollex) length; PL, palm length. Not to scale (for scales and specimen details see Figs. 3, 10, 15, 20, 28, 34, 39, 42, 54, 58); C, F, G mirrored horizontally from the originals for better visual comparison.

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 66. Colour patterns of 11 western Atlantic species of the Alpheus armillatus H. Milne Edwards, 1837 complex and A. viridari (Armstrong, 1949): 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.; L. A. viridari (Armstrong, 1949). All photographs by the author

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

FIGURE 68. Colour of the plunger of the major chela dactylus in five species of the Alpheus armillatus H. Milne Edwards, 1837 com-

FIGURE 69. Juvenile colour patterns of five western Atlantic species of the Alpheus armillatus H. Milne Edwards, 1837 complex [specimens not deposited]: A, B, A. armillatus H. Milne Edwards, 1837; C, A. amarillo sp. nov.; D, A. mathewsae sp. nov.; E, A. punctatus sp. nov.; F, A. angulosus McClure, 2002. All photographs by the author.

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.