Rochinia A. Milne-Edwards, 1875

Ng, Peter K. L. & Forges, Bertrand Richer De, 2007, A new species of deep-water spider crab of the genus Rochinia A. Milne-Edwards, 1875, from Guam (Crustacea: Brachyura: Majidae), Zootaxa 1610, pp. 61-68 : 61-63

publication ID	https://doi.org/ 10.5281/zenodo.178904
DOI	https://doi.org/10.5281/zenodo.3503417
persistent identifier	https://treatment.plazi.org/id/FD4C87DD-FFC3-397F-FF6E-F8DA5B44FF2B
treatment provided by	Plazi
scientific name	Rochinia A. Milne-Edwards, 1875
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Rochinia A. Milne-Edwards, 1875 View in CoL

Remarks. The genus Rochinia was described by A. Milne-Edwards (1875) for Rochinia gracilipes A. Milne- Edwards, 1875, from Mexico in the Atlantic Ocean. Griffin and Tranter (1986) modified the definition of the genus in order to include several species having plates on their carapaces. In doing so, the genera Sphenocarcinus A. Milne-Edwards, 1875 , and Oxypleurodon Miers, 1886 , became subjective synonyms of Rochinia . Several authors, however, have disagreed with this decision and proposed alternative classification schemes for the dozens of species in Rochinia sensu lato. Tavares (1991) described a new genus, Nasutocarcinus Tavares, 1991 , from the Indian Ocean for a group of “ Rochinia ” species having distinctive carapace plates, an elongated rostrum in which the two spines are completely fused along their entire length and relative long ambulatory legs. He also resurrected Sphenocarcinus for two American species, S. agassizi and S. corrosus ; as well as Oxypleurodon for species with carapace plates, chelipeds as long as the P2 and usually with a bifid rostrum which has a V-shaped cleft ( O. auritus , O. bipartitus , O. mammatus , O. orbiculatus , O. sphenocarcinoides and O. stimpsoni ). Tavares (1991) left the remaining species tentatively in Rochinia sensu lato. Richer de Forges (1992) also commented that Sphenocarcinus was distinct from Rochinia . Richer de Forges (1995) later commented that Tavares’ (1991) use of the relative length of the cheliped to the P2 was not useful and placed all “ Rochinia ” species with carapace plates and bifid rostrums from the Indo-West Pacific in Oxypleurodon (see also Davie 2002). Although Richer de Forges (1995) did not list all the species he recognized in Oxypleurodon , his definition is simple enough to use to separate those referred to Rochinia by Griffin & Tranter (1986). Following these last authors, the redefined genus Rochinia contains at present only 24 species in the Indo-West Pacific, including the new species from Guam described herein ( Table 1). The remaining 10 species are from the northeastern Atlantic, western Atlantic and eastern Pacific. We also list the species currently placed in Nasutocarcinus Tavares, 1991 , Oxypleurodon Miers, 1886 , and Sphenocarcinus A. Milne- Edwards, 1878 ( Table 2). The genus Oxypleurodon as defined at present includes 17 species. Even so, the taxonomy of these genera cannot be regarded as settled. Our ongoing studies suggest that the two species now placed in Sphenocarcinus differ markedly in many characters, suggesting that they may not be congeneric. The composition of Rochinia is also still very unsatisfactory and a full revision is urgently needed.