Xiphonectes aculeatus sp. nov., a new swimming crab (Crustacea: Decapoda: Portunidae) from Madagascar

Abstract

Here we describe a new species of Xiphonectes A. Milne-Edwards, 1873 (Brachyura: Portunidae) from southern Madagascar. Xiphonectes aculeatus sp. nov. is morphologically most similar to X. latibrachium (Rathbun, 1906) from Hawaii, and X. paralatibrachium Crosnier, 2002, from the Marquesas Islands, French Polynesia. All three species have a carapace with six anterolateral teeth, a long spine on the inner dorsal margin of the cheliped carpus, and a produced, flattened, anterior region on the third maxilliped merus. Among these species, Xiphonectes aculeatus sp. nov. is easily distinguished by the acutely produced posterodistal angle on the meri of its swimming legs, dorsal and marginal structures on its carapace, and most notably, the shape of its frontal teeth.

A revision of the swimming crabs of the Indo – West Pacific Xiphonectes hastatoides (Fabricius, 1798) species complex (Crustacea: Brachyura: Portunidae)

“…REMARKS. Xiphonectes A. Milne-Edwards, 1873, currently contains 34 species and subspecies: X. aculeatus Koch et Ďuriš, 2019, X. alcocki (Nobili, 1906, X. andersoni (De Man, 1887), X. arabicus (Nobili, 1905) (= P. (H.) acerbiterminalis Stephenson et Rees, 1967), X. brockii (De Man, 1887), X. dayawanensis (Chen, 1986), X. gracillimus (Stimpson, 1858), X. guinotae (Stephenson et Rees, 1961), X. hainanensis (Chen, 1986), X. hastatoides (Fabricius, 1798) (= P. hastatoides Weber, 1795), X. iranjae (Crosnier, 1962), X. latibrachium (Rathbun, 1906), X. longispinosus var. bidens (Laurie, 1906), X. l. longimerus (Spiridonov, 1994), X. longispinosus longispinosus (Dana, 1852) (= A. vigilans Dana, 1852; P.…”

“…leptocheles A. Milne-Edwards, 1873), X. l. obtusidentatus Miers, 1884, X. macrophthalmus (Rathbun, 1906, X. mariei (Guinot, 1957), X. paralatibrachium (Crosnier, 2002), X. pseudohastatoides (Yang et Tang, 2006), X. pseudotenuipes (Spiridonov, 1999), X. pulchricristatus (Gordon, 1931) (= Neptunus (H.) alcocki Gordon, 1930), X. rugosus (A. Milne-Edwards, 1861), X. spiniferus (Stephenson et Rees, 1967), X. spinipes (Miers, 1886), X. stephensoni (Moosa, 1981) (= P. (H.) emarginatus Stephenson et Campbell, 1959), X. tenuicaudatus (Stephenson, 1961), X. tenuipes (De Haan, 1835), X. tridentatus (Yang, Dai et Song, 1979), X. trilobatus (Stephenson, 1972), X. tuberculosus (A. Milne-Edwards, 1861), X. tuerkayi Spiridonov, 2016, X. tweediei (Shen, 1937, and X. unidens (Laurie, 1906) (cf. Ng et al [2008]; Koch, Ďuriš [2019]). All are characterised by the posteroexternal carapace angle being distinctly angular and/or armed with a spine.…”

“…Spiridonov et al [2014], in their broad overview of the Portunoidea, treated all the subgenera as full genera, and transferred Lupocycloporus from the Portuninae to the Lupocyclinae Alcock, 1899. Koch & Ďuriš [2018Koch & Ďuriš [ , 2019, Koch et al [2015aKoch et al [ , b, 2019 and Windsor et al [2019] also treat Monomia and Xiphonectes as distinct genera. The various Portunus subgenera recognised are certainly relatively distinct and giving them genera status, at least based on their respective type species, does not pose serious problems.…”