The Shrimp Genus Leptalpheus Williams, 1965 in the Southwestern Caribbean Sea, with Description of One New Species from Panama (Crustacea, Decapoda, Alpheidae)
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The shrimp genus Leptalpheus Williams, 1965 in the southwestern Caribbean Sea, with description of one new species from Panama (Crustacea, Decapoda, Alpheidae) Arthur ANKER Instituto Smithsonian de Investigaciones Tropicales, apartado 0843-03092, Balboa, Ancón, Panamá (Panama) Current address: Florida Museum of Natural History, University of Florida, 250A Dickinson Hall, Gainesville, FL 32611-7800 (USA) aanker@fl mnh.ufl .edu Anker A. 2008. — The shrimp genus Leptalpheus Williams, 1965 in the southwestern Caribbean Sea, with description of one new species from Panama (Crustacea, Decapoda, Alpheidae). Zoosystema 30 (4) : 781-794. ABSTRACT Two species of the alpheid shrimp genus Leptalpheus Williams, 1965 are reported from the southwestern Caribbean Sea. Leptalpheus pierrenoeli n. sp. is described on the basis of a single male specimen collected from a burrow of unknown, presumably callianassid host on Isla Grande, Panama. Th is species diff ers from all other species of Leptalpheus by the dentition on the fi ngers of the major KEY WORDS cheliped and the elongate stylocerite. Leptalpheus cf. forceps is recorded for the Crustacea, fi rst time from Cahuita, Costa Rica, representing a considerable range extension Decapoda, of L. forceps Williams, 1965, previously known from North Carolina to the Alpheidae, Leptalpheus, Gulf of Mexico, into the southern Caribbean Sea. Th e Cahuita specimens bear Callianassidae, a peculiar segmented fi lament on the uropodal endopod (caudal fi lament), a Lepidophthalmus, Caribbean, feature not observed in the type specimens. Furthermore, they were found in western Atlantic association with the callianassid ghostshrimp, Lepidophthalmus richardi Felder & infaunal shrimp, Manning, 1997. Th is fi nding represents a new host record for L. forceps and burrow, commensalism, a signifi cant range extension of L. richardi, previously known only from the new species. type locality in Belize. ZOOSYSTEMA • 2008 • 30 (4) © Publications Scientifi ques du Muséum national d’Histoire naturelle, Paris. www.zoosystema.com 781 Anker A. RÉSUMÉ Le genre de crevettes Leptalpheus Williams, 1965 dans le sud-ouest de la mer des Caraïbes, et description d’une nouvelle espèce du Panama (Crustacea, Decapoda, Alpheidae). Deux espèces de crevettes alphéidées du genre Leptalpheus Williams, 1965 sont signalées du sud-ouest de la mer des Caraïbes. Leptalpheus pierrenoeli n. sp. est décrite d’après un unique spécimen mâle trouvé dans un terrier d’un hôte inconnu, probablement une crevette-taupe (Callianassidae), à Isla Grande au Panama. Cette espèce se distingue des autres espèces du genre Leptalpheus par la dentition sur les doigts de la grande pince et un stylocérite allongé. Leptalpheus cf. forceps MOTS CLÉS est signalé pour la première fois de Cahuita au Costa Rica, ce qui représente une Crustacea, extension considérable de l’aire de distribution de L. forceps Williams, 1965, Decapoda, précédemment connue de la Caroline du Nord jusqu’au Golfe du Mexique, Alpheidae, Leptalpheus, au sud de la mer des Caraïbes. Les deux spécimens mâles de L. cf. forceps de Callianassidae, Cahuita possèdent un fi lament segmenté sur l’endopodite de l’uropode (fi lament Lepidophthalmus, Caraïbe, caudal), celui-ci faisant défaut chez les spécimens types. En outre, ils ont été Atlantique occidental, trouvés en association avec un callianassidé, Lepidophthalmus richardi Felder & crevette, Manning, 1997, ce qui représente une nouvelle association pour L. forceps, mais faune des terriers, commensalisme, aussi un élargissement considérable de l’aire de distribution de L. richardi, qui espèce nouvelle. auparavant n’était connue que de la localité type au Belize. INTRODUCTION Borradaile, 1903 (see Anker et al. 2006b). Between October and November 2005, the author investigated Th e genus Leptalpheus Williams, 1965 was estab- various types of burrows and mounds at two locali- lished for the peculiar alpheid shrimp Leptalpheus ties in the southwestern Caribbean Sea: Isla Grande, forceps Williams, 1965 originally described from Panama, and Cahuita, Costa Rica. At Isla Grande, North Carolina in the southeastern USA. Since a single specimen of Leptalpheus was collected in then several species were described in this genus, the shallow subtidal, from a burrow of an unknown two of them in the western Atlantic: L. axianassae (presumably callianassid) host. Th is specimen was Dworschak & Coelho, 1999 (subjective junior immediately recognized to represent an undescribed synonym L. petronii Ramos-Porto & Souza, 1994; species of Leptalpheus, but all subsequent attempts see Anker et al. 2006b) from Brazil, and L. felderi to collect more Leptalpheus specimens at this lo- Anker, Vera Caripe & Lira, 2006 from Venezuela cality ended unsuccessfully. Fortunately, the Isla and Colombia (Dworschak & Coelho 1999; Anker Grande specimen was a complete adult male with et al. 2006b). Anker et al. (2006b) provided a table several unique features separating its species from with all known records of Leptalpheus species, all other species of Leptalpheus thus fully justifying showing presence of at least three undescribed taxa the below description of the new species based on in the western Atlantic, defi ned three species groups a single specimen. At Cahuita, three specimens of within Leptalpheus, based mainly on the features of Leptalpheus were collected, two of them together the major cheliped. with their callianassid hosts. Th ey were identifi ed as All species of Leptalpheus appear to be associated Leptalpheus cf. forceps, a species that was not previ- with burrows of thalassinidean mudshrimps be- ously reported from the southwestern Caribbean. longing to the families Callianassidae Dana, 1852, Because of some diff erences observed between the Upogebiidae Borradaile, 1903 and Laomediidae Cahuita specimens and the type of L. forceps from 782 ZOOSYSTEMA • 2008 • 30 (4) A new Leptalpheus (Crustacea, Decapoda, Alpheidae) from Panama North Carolina, detailed drawings of one of the Alpheidae (Anker 2001), and also in recognition of his Cahuita specimens are provided. Th e species groups numerous contributions to the biology and taxonomy of Leptalpheus proposed by Anker et al. (2006b) are of caridean shrimps. briefl y discussed. TYPE LOCALITY. — Isla Grande, Caribbean coast of Panama. DISTRIBUTION. — Tropical western Atlantic: presently MATERIAL AND METHODS known only from the type locality: Isla Grande, Caribbean coast of Panama. All specimens were collected from burrows with the aid of Alvey bait suction (“yabby”) pump. Most DESCRIPTION were photographed alive after capture and preserved Body moderately slender (Fig. 3A, B), carapace and in 75% ethanol; one specimen was preserved in abdomen slightly compressed laterally, glabrous. Ambion RNA-later for genetic studies. Th e holotype Carapace with hardly visible anterolateral suture of the new species is deposited in the collections proximal to base of antenna (Fig. 1B). Frontal of the Muséum national d’Histoire naturelle, Paris margin with broad, subtriangular, bluntly ending (MNHN). Th e material of L. forceps is deposited rostral projection, without orbital teeth or crests in the MNHN and the Universidad de Costa Rica, (Fig. 1B). Pterygostomial angle bluntly protruding Museo de Zoología, San José (UCRMZ). Th e anteriorly; branchiostegial region with pronounced hosts were identifi ed using Manning & Felder lip anteriorly (Fig. 1B); cardiac notch deep. Eyes (1991) and Sakai (1999). Carapace length (CL) not visible in dorsal view, anterior portion visible and total length (TL) were measured in mm from in lateral view (Fig. 1A, B); anteromesial process the anterior margin of the carapace (or tip of the bluntly subtriangular, feebly protruding (Fig. 1B); rostral projection) to the posterior margin of the cornea small, lateral, pigmented (Fig. 1B). Ocellar carapace and telson, respectively. beak not conspicuous. Antennular peduncle relatively stout (Fig. 1A), OTHER ABBREVIATIONS second segment about 1.5 times as long as broad, fcn fi eld collection number; longer than dorsally visible portion of fi rst seg- Mxp maxilliped; ment; stylocerite slightly exceeding distal margin P pereiopod. of fi rst segment, acute distally (Fig. 1A); ventro- mesial carina of fi rst segment with very strong, SYSTEMATICS anteriorly acute tooth; lateral fl agellum biramous, with shorter ramus distinct, inserted at fourth seg- Family ALPHEIDAE Rafi nesque, 1815 ment (Fig. 1B). Antenna with basicerite bearing Genus Leptalpheus Williams, 1965 strong ventrolateral tooth (Fig. 1B); scaphocerite broadly ovate, anterior margin of blade slightly Leptalpheus pierrenoeli n. sp. convex, not protruding beyond distolateral tooth (Figs 1; 2; 3A, B) (Fig. 1A); carpocerite long, stout, reaching far be- yond scaphocerite (Fig. 1A, B). Leptalpheus sp. 4 aff . forceps – Anker et al. 2006b: 686. Mouthparts not dissected, appearing typical for genus in external view. Th ird maxilleped moderately TYPE MATERIAL. — Holotype: Panama, Caribbean coast, Isla Grande, southern shore, village, near Cabañas Super slender, elongate; lateral plate acutely produced Jackson, from burrow, bait suction pump, depth 0.5-1 m, (Fig. 1C); ultimate segment with rows of long, coll. A. Anker and C. Hurt, 6.X.2005, fcn 05-105, 1 ♂, distally thickened setae, tip unarmed; arthrobranch CL 4.5, TL 14.6 (MNHN-Na 17067). well developed (Fig. 1C). Chelipeds strongly asymmetrical in shape, unequal ETYMOLOGY. — Th is new species is named after Dr Pierre Y. Noël (MNHN), who directed the author’s in size (Fig. 2), carried folded (Fig. 3A). Major