Alpheus peasei (Armstrong 1940)

Ecology. Found in intertidal areas up to 51.8 m depth (Martínez-Iglesias et al. 1997; Anker et al. 2016; this study). Inhabits polychaete tubes, coral rubble, dead corals, and calcareous algae, and it is found under rocks or in rock crevices, among mangrove roots near the coast (Carvacho 1979; Santos et al. 2012), and occasionally in sponges of the genus Callyspongia Duchassaing & Michelotti, 1864 (Chace 1956). Colour in life. Body color ranges from greenish-yellow to reddish (Rodriguez 1986; Sterrer 1986; Anker et al. 2016). According to Anker et al. (2016), the large white spots with brown chromatophores on the major chela are an accurate diagnostic character. Fresh specimens examined by us were predominantly greenish-yellow. However, we also observed specimens with body and appendages transparent with reddish chromatophores. Eggs in initial stage are olive green.

Redescription. (Based on an ovigerous female, Recife, Pernambuco, MOUFPE 19428 and compared with the examined type material). Carapace smooth; rostrum triangular, carinate, tip acute, reaching half-length of first article of antennular peduncle (Fig. 1 A). Ocular hoods dorsally inflated, with strong acute tooth arising from dorsomesial margin, margin between rostrum and orbital hoods sinuous. Eyes well-pigmented, completely covered by ocular hoods in dorsal and lateral views (Fig. 1 A, B). Cardiac notch well-developed. Pleonal somites smooth; ventral and posterior margins of pleurae 1 – 4 broadly rounded and pleura of fifth segment subtriangular; sixth pleura without articulated plate. Telson (Fig. 1 C) tapering distally, proximal region wider than distal; dorsal surface with two pairs of strong spiniform setae inserted at some distance from lateral margin, first pair anterior and second pair posterior to telson mid-length; distal margin of telson slightly convex, with two pairs of posterolateral spiniform setae, lateral about 2.5 times as long as mesial; anal tubercles well-developed. Uropods (Fig. 1 C) with bifid protopods, each lobe ending in acute tooth; exopod longer than endopod; lateral margin of exopod almost straight; diaeresis sinuous, with one adjacent and internal tooth, separated by stout distolateral spiniform setae, overreaching distal margin of exopod; three very small spiniform setae before distal margin; endopod with row of small spiniform setae along distolateral margin. Antennular peduncle moderately slender. Stylocerite distally acute, not reaching distal margin of first article of antennular peduncle; ventromesial carina subtriangular, large, with small tooth in ventrodistal margin (Fig. 1 D); second article about 1.2 times longer than dorsally visible portion of first article, about 2.2 times length of third article; third article about 1.5 times longer than wide (Fig. 1 A). Antenna basicerite broad, distolateral tooth directed forward; carpocerite slightly exceeding both scaphocerite and distal portion of third antennular article; scaphocerite with shallowly concave lateral margin and large, acute distolateral tooth reaching far beyond distal margin of narrow blade (Fig. 1 A). Mandible (Fig. 1 E) with 2 - jointed palp; incisor process robust, with 10 distinct teeth, mesial tooth conspicuously wider and longer than others; molar process stout, with semicircular rows of short setae. First maxilla (Fig. 1 F) with palp bilobed, inferior lobe bearing 1 slender seta, superior lobe not setose. Second maxilla (Fig. 1 G) palp well-developed, slender; with upper lacinia cleft, lower lacinia with single lobe; scaphognathite larger than both laciniae, extremities rounded and lateral margin sinuous. First maxilliped (Fig. 1 H) palp approximately 2.2 times longer than wide; two laciniae separated by distinct cleft, exopod well-developed with long flagellum and distinct exopodal lobe; epipod about 2.4 times longer than wide. Second maxilliped (Fig. 1 I) exopod well-developed, flagellum 2.6 times longer than epipod; epipod about 2.1 times as long as wide. Third maxilliped (Fig. 1 J) slender, when extended forward, slightly overreaching distal margin of third article of antennular peduncle; antepenultimate article not flattened or expanded, 1.6 times longer than ultimate article; penultimate article shortest of all, about 2.2 times as long as wide, lateral margin smooth, with tufts of setae, distomesial margin with two thick setae; ultimate article tapering distally, smooth, with several rows of setae, 1.4 times longer than penultimate article, very setose; exopod overreaching distal margin of antepenultimate article, ending in long flagellum; artrobranch well-developed. Epipod present on third maxilliped and from pereiopods 1 – 4. Major cheliped (Fig. 2 A, B) palm strongly sculptured, twisted. Palm about 2.3 times as long as wide, ventral notch broad and shallow, dorsal notch deep and narrow; linea impressa well-marked; lateral surface with low crest starting at about 0.6 times length of palm and ending in sharp distodorsal tooth; ventral margin with rounded, smooth, non-projecting shoulder adjacent to shallow notch, notch continuing transversely into shallow groove on mesial surface; distomesial margin with subcylindrical elevation ending in large adhesive disk distally; distomesial surface with transversally deeply notched crest ending in sharp tooth; dactylus twisted laterally, opening and closing in nearly horizontal plane; strongly arched; compressed proximally; slightly bulbous distally; plunger short (Fig. 2 I). Pollex shorter than dactylus; ischium short, stout and unarmed; merus about three times longer than carpus, with distal margin unarmed, ventromesial surface with three small spiniform setae; carpus short and unarmed, cup-shaped. Minor cheliped (Fig. 2 C, D) chela slightly compressed, with palm sculptured distally; lateral surface with short crest starting at distal third of palm and ending in sharp distodorsal tooth; ventral margin with blunt, non-protruding shoulder, distomesial margin with subcylindrical elevation ending distally in small adhesive disk; distomesial surface with crest ending in short sharp tooth; fingers as long as palm; pollex shallowly excavated on cutting edge; dactylus somewhat flattened and twisted laterally, slightly convex dorsally, proximally with small adhesive disk; ischium short, stout and unarmed; merus about 2.5 times longer than carpus, with distal margin unarmed, ventromesial surface unarmed; carpus short and unarmed, cup-shaped. Second pereiopod slender (Fig. 2 E). Merus slightly longer than ischium; carpus five-segmented, segment ratio (proximal to distal) 3: 2.5: 1: 1: 1.5; distalmost carpal article shorter than chela; chela simple; fingers slightly longer than palm. Third (Fig. 2 F) and fourth (Fig. 2 G) pereiopods similar in shape and length; both with ischium armed with spiniform seta on ventrolateral surface; merus with ventrodistal tooth; carpus with pair of ventrodistal spiniform setae; propodus with six pairs of strong spiniform setae along ventral margin; dactylus biunguiculate, tooth on flexor margin shorter than extensor margin. Fifth pereiopod (Fig. 2 H) shorter than P 3 and P 4; ischium, merus and carpus unarmed; merus slightly longer than carpus; propodus with five single spiniform setae and one distal pair on ventral margin; dactylus biunguiculate, tooth on flexor margin shorter than extensor margin. Morphological variation. There was no solid morphological variation in the examined characters, considering all specimens and localities. However, the following variations were detected: ventromesial carina of the first article of antennular peduncle was unarmed or armed with a tooth that ranged from small to well-developed. The inner margin of the teeth on ocular hoods ranged from almost straight to slightly convex. The distolateral tooth of the scaphocerite may be either shorter, subequal, or slightly overreaching the distal margin of carpocerite and third article of antennular peduncle. The number of small spiniform setae near the distal margin of the uropodal exopod varied from one to nine (most frequently five). The number of thickened setae on the penultimate article of the third maxilliped varied from one to three (frequently two). The fingers of the minor chela are slightly longer or shorter than the palm. The number of spiniform setae on the ventromesial margin of the merus of the major chela varied from none to six (most frequently four); these setae seem to be easily lost. The form of the molar tooth (Fig. 2 I) may be either subtriangular or more subquadrate. The number of pairs of ventral spiniform setae on pereiopods 3 and 4 varied from five to eight (most frequently six pairs in both appendages). The number of single spiniform setae on the ventral surface of pereiopod 5 ranged from three to eight (most frequently five). No sexual dimorphism was observed.

Diagnosis. Rostrum dorsally carinate. Orbital hoods toothed. Ventrolateral tooth on basicerite overreaching stylocerite. Third and fourth pereiopods with spiniform setae on ventrolateral surface of ischium and one tooth on ventrodistal margin of merus.

Distribution. Western Atlantic: Bermuda; United States of America: Florida, Texas; Mexico: Yucatan, Isla of Cozumel, Bahía de la Ascension, Bahía del Espíritu Santo; Belize; Cuba; Costa Rica; Panama; Colombia: Providence Island; Curaçao; Bonaire; Porto Rico; Anguilla; Saint Kitts and Nevis; Barbuda; Antigua; Guadeloupe; Dominica; Saint Lucia; Barbados; Tobago Cays; Trinidad and Tobago; Venezuela; Brazil: Ceará, Pernambuco, Bahia, Rio de Janeiro, Trindade and Martin Vaz Archipelago (Armstrong 1940; Chace 1972; Rodríguez 1980; Santos et al. 2012; Cunha et al. 2015; Anker et al. 2016; Pachelle et al. 2016; this study) (Fig. 3).

Holotype. Bermuda, Castle Harbor Reefs, AMNH 8184. Not examined. Material examined. Bermuda. Paratypes: 2 males, 2 ovig. females, Castle Harbor, VIII. 1938, lot 123, AMNH 8186; 9 males, 4 (3 ovig.) females, Grazbury’s Island, VIII. 1938, lot 127, AMNH 8186; 5 males, 4 (2 ovig.) females, Castle Harbor, on reef, VIII. 1938, lot 133, AMNH 8186; 2 males, St. Davids, on reef, VIII. 1938, lot 138, AMNH 8186. Other material. Bermuda. 4 males, 4 (2 ovig.) females, Ferry Beach, on rocks, coll. B. A. Hazlett, 02. VIII. 1960, USNM 107080; 2 ovig. females, South Shore, on rocks, coll. B. A. Hazlett, 10. VIII. 1960, USNM 107079; 2 males, Castle Harbor, in calcareous rocks, coll. B. A. Hazlett, 21. VII. 1960, USNM 107081; 2 males, 1 ovig. female, Castle Harbor, off Charles Island, in calcareous rocks, coll. J. M. Moulton, 25. VII. 1958, USNM 102370. United States of America. 1 male, Florida, St. Lucie County, in limestone reef and Phragmatopoma sp., 6 m, USNM 170085. Mexico. 1 male, 1 ovig. female, 1 juv, Quintana Roo, Ascension Bay, Center of Nicchehabin Reef, coll. E. L. Bousfield, 1 – 2 m, 14. IV. 1960, USNM 136040; 1 male, Quintana Roo, Puerto Morelos, María Irene Beach, CNCR 9631; 1 male, Quintana Roo, Isla Cozumel, Playa Aventura, CNCR 20292; 1 ovig. female, Quintana Roo, Arrecife Cacarracas, Frente Puerto Morelos, CNCR 5733; 1 ni, Quintana Roo, Punta El Placer, Campaña Edwin Link, CNCR 10872; 1 ni, Quintana Roo, Punta Pulticub, CNCR 20306. Belize. 1 male, Carrie Bow Cay, coll. K. Sandved, 1 m, IV. 1974, USNM 184488. Costa Rica. 2 males, 1 ovig. female, Parque Nacional Cahuita, Limón, Puerto Vargas, colls. R. Heard, L. Rodriguez & R. Vargas, 19. XI. 1999, MZUCR 2312 - 33. Panama. 1 male, Isla Grande, off W point, in coral rocks, colls. A. Anker & C. Hurt, 1 – 2 m, 06. X. 2005, MZUSP 33123; 1 male, Bocas del Toro, Bocas del Drago, colls. F. L. Mantelatto, A. Baeza, I. Miranda & M. Terossi, 17. II. 2009, CCDB 3493; Colombia. 4 males, 3 ovig. females, old Providence, in reef, coll. W. L. Schmitt, 06. VIII. 1938, USNM 77890. Netherlands Antilles: 1 male, Curaçao, Piscaderabaai, coll. J. G den Hartog, 26. I. 1972, RMNH. CRUS. D. 30635; 1 ovig. female, Bonaire, Kralendijk, 09. VIII. 1994, RMNH. CRUS. D. 46177; 1 ovig. female, coll. R. V. Harrison, 2 – 3 m, II. 1975, USNM 155674. Saint Kitts and Nevis. 1 male, 3 (2 ovig.) females, St. Kitts, Windward Beach, on coral reef, colls. W. L. Schmitt & D. V. Nicholson, 12. VI. 1956, USNM 136030. Antigua and Barbuda. 2 males, 3 ovig. females, Antigua Island, English Harbor, Charlotte point, 02. VI. 1956, USNM 136029. Guadeloupe. 1 male, 1 ovig. female, Guadeloupe, Karubenthos, GB 09, MNHN-IU- 2013 - 12050. Dominica. 1 male, 2 ovig. females, 5 juv, West of Portsmouth, between rocks and dead coral Acropora sp., 1 m, 19. VI. 1959, USNM 136035. Saint Lucia. 1 male, 1 ovig. female, the outside Pigeon Island Reef, in coral, 16. VI. 1959, USNM 136034. Barbados. 1 male, off the Castle E, side Barbados, coll. C. C. Nutting, 1 – 4 m, USNM 68724. Trinidad and Tobago. 5 (3 ovig.) females, Tobago Island, Buccoo Reef, coll. W. L. Schmitt, 05. VI. 1959, USNM 136033. Brazil. 1 male, 1 ovig. female, Pernambuco, Recife, 8 ° 13 ’ 52.1 ” S 34 ° 37 ’ 41.2 ” W, REC II, dredge 8, coral rubble, colls. A. M. S. Cunha, C. A. L. Santos Júnior, G. O. Soledade, F. D. Silva, R. Guéron & P. S. Santos, 51.8 m, 27. II. 2018, MOUFPE 19427; 1 ovig. female, 8 ° 13 ’ 33.0 ” S 34 ° 37 ’ 40.3 ” W, dredge 5, 50.6 m, same collection data, MOUFPE 19428; 1 ovig. female, 8 ° 13 ’ 52.1 ” S 34 ° 37 ’ 42.7 ” W, dredge 10, 50 m, same collection data, MOUFPE 19429; 1 male, 8 ° 13 ’ 52.1 ” S 34 ° 37 ’ 42.7 ” W, dredge 10, in dead coral, 50 m, same collection data, MOUFPE 19430; 1 male, 8 ° 13 ’ 52.1 ” S 34 ° 37 ’ 41.2 ” W, dredge 8, 51.8 m, same collection data, MOUFPE 19431; 1 male, 1 ovig. female, Bahia, Maraú, Taipús de Fora Beach, colls. P. S. Santos, G. O. Soledade & A. O. Almeida, in dead coral, salinity 38, 30. VII. 2011, MOUFPE 19432; 2 males, 3 (2 ovig.) females, Bahia, Maraú, Algodões Beach, colls. P. S. Santos, G. O. Soledade & A. O. Almeida, salinity 38, 01. VIII. 2011, MOUFPE 19433; 2 males, 4 (3 ovig.) females, Rio de Janeiro, Campos Basin, Petrobrás, Biofouling on Platform P- 55 (Old SS- 06), coll. J. B. Mendonça, 16 m, 30. III. 2010, MZUSP 25346; 1 male, 1 ovig. female, Rio de Janeiro, Búzios, Tartaruga Beach, MNRJ 3478; 1 male, Trindade Island, between Crista do Galo and Ponta Norte, 20 ° 29 ’ 14.8 ” S 29 ° 20 ’ 13.9 ” W, scuba diving, coll. J. B. Mendonça, 15 m, 21. V. 2014, MZUSP 33263; 1 male, Trindade Island, Enseada dos Portugueses, Ponta da Calheta, 20 ° 30 ’ 18.7 ” S 29 ° 18 ’ 31.6 ” W, scuba diving, coll. J. B. Mendonça, 16.3 m, 21. V. 2014, MZUSP 33295; 1 male, Trindade Island, Enseada dos Portugueses, SECON / ECIT, 20 º 30 ’ 20.9 ” S 29 º 18 ’ 43.7 ” W, scuba diving, 9 m, 21. V. 2014, MZUSP 33246; 3 males, 2 ovig. females, Trindade Island, Enseada da Cachoeira, Farrilhões, 20 ° 31 ’ 22.4 ” S 29 ° 19 ’ 52.0 ” W, scuba diving, 14.4 m, 5. V. 2014, MZUSP 33336.