Leptalpheus Williams 1965
Creators: name: Anker, Arthur
Publisher: name: Zenodo
Year: 2011
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Alpheidae
Leptalpheus

description: Leptalpheus Williams, 1965
Leptalpheus Williams, 1965: 193.
Emended diagnosis. Carapace glabrous, not setose; frontal margin without orbital teeth, rounded or with more or less developed median rostral projection; small orbital crests present or absent; anterolateral suture present; pterygostomial angle rounded; branchiostegial margin with narrow ventral lip; posterior margin with deep cardiac notch. Sixth abdominal somite with posteroventral articulated plate. Telson with two pairs of spiniform setae dorsally; posterior margin rounded, with two pairs of posterolateral spiniform setae; anal tubercles more or less developed. Eyes concealed in dorsal and lateral views; anteromesial margin bluntly projecting. Antennular peduncles sometimes flattened dorsoventrally; ventromesial carina of first article with strong tooth; stylocerite appressed or not, rarely exceeding distal margin of first article; second article varying from shorter to much longer than wide; lateral antennular flagellum with short secondary ramus. Antenna with basicerite bearing distoventral tooth; scaphocerite with distolateral tooth; carpocerite exceeding scaphocerite. Mouthparts not especially modified; mandible with two-articulated palp; first maxilliped with elongate palp and broad caridean lobe; second maxilliped with elongate epipod. Third maxilliped with lateral plate on coxa more or less produced dorsally; tip of ultimate article unarmed. First pereiopods (chelipeds) very unequal in size and asymmetrical in shape, carried flexed; major cheliped elongate, with enlarged, elongate chela; merus depressed ventrally, with margins smooth, rugose or furnished with tubercles; carpus short, more or less cup-shaped; palm ventromesially depressed, smooth or with row or fields of tubercles; fingers with variously shaped armature, without tooth-fossa system; adhesive discs present or absent. Second pereiopod with carpus composed of four or five articles. Third pereiopod and fourth pereiopods strongly compressed laterally; ischium with or without spiniform seta ventrolaterally; carpus with distoventral spiniform seta; propodus with spiniform setae on ventral margin; dactylus simple, conical. Fifth pereiopod not compressed, shorter and more slender than third and fourth pereiopods; propodus with at least three setal rows distolaterally. Male second pleopod with appendix masculina exceeding appendix interna; female second pleopod with appendix interna only. Uropod with lateral lobe of protopod bifid distally; exopod distally rounded or truncate; endopod sometimes produced into posterior filament; diaeresis with deep incision and large triangular tooth near mesial margin of exopod. Gill/exopod formula: 5 pleurobranchs (P1–5), 1 arthrobranch (Mxp3), 2 lobe-like epipods (Mxp1–2), 0 podobranchs, 5 mastigobranchs (Mxp3, P1–4), 5 setobranchs (P1–5), 3 exopods (Mxp1–3).
Species included. Leptalpheus forceps Williams, 1965 (type species), L. pacificus Banner & Banner, 1974, L. mexicanus Ríos & Carvacho, 1983, L. axianassae Dworschak & Coelho, 1999 (? = L. petronii Ramos-Porto & Souza, 1994, nomen dubium, see Anker et al. 2006 for discussion), L. felderi Anker, Vera Caripe & Lira, 2006, L. pierrenoeli Anker, 2008, L. denticulatus Anker & Marin, 2009, L. dworschaki Anker & Marin, 2009, L. marginalis sp. nov., L. azuero sp. nov., L. penicillatus sp. nov., L. hendrickxi sp. nov., L. bicristatus sp. nov.
Distribution. Pantropical except for East Atlantic. Indo-West Pacific: Madagascar, Vietnam, Philippines, Fiji, French Polynesia, Hawaii. East Pacific: Mexico, Nicaragua, Costa Rica, Panama, Colombia. West Atlantic: southeastern USA (North Carolina, Florida, Louisiana), Venezuela, Aruba, Panama, Costa Rica, Brazil (Sergipe, São Paulo).
Remarks. The increasing morphological diversity of Leptalpheus, especially in the proportions of the antennular peduncles, the shape and length of the stylocerite, and the armature of the major chela fingers, calls for a phylogenetic investigation of this genus. It is possible that some morphologically and genetically well-defined clades will be assigned to new subgenera or even genera. However, in the absence of molecular data for many taxa and in the presence of further undescribed species (Felder et al. 2003; Anker et al. 2006; see also below), a subdivision of Leptalpheus in either subgenera or genera is not possible at this time.
description: Published as part of Anker, Arthur, 2011, Six new species and three new records of infaunal alpheid shrimps from the genera Leptalpheus Williams, 1965 and Fenneralpheus Felder & Manning, 1986 (Crustacea, Decapoda), pp. 1-38 in Zootaxa 3041 on page 3, DOI: 10.5281/zenodo.278802