Stenorhynchus spinifer Miers 1885: 586

Froglia, Carlo & Clark, Paul F., 2011, The forgotten Narrative of H. M. S. Challenger and the implications for decapod nomenclature, Zootaxa 2788, pp. 45-56 : 49

Stenorhynchus spinifer Miers 1885: 586 ; 1886: 7, pl. I, fig. 2.

Remarks. The 1885 description is short: “... a new species of Stenorhynchus ( Stenorhynchus spinifer ), distinguished from all its congeners by the strongly developed supra-ocular and post-ocular spines”. A more extended description, together with a figure of the anterior part of carapace, were provided by Miers (1886: 7, pl. I, fig. 2). Both descriptions were based on a mutilated specimen devoid of all legs, dredged off St. Paul’s Rocks in the South Atlantic. Holthuis et al. (1980) in their review of the decapods of St Paul’s Rocks commented that “So far as we know the species has not been reported upon since its original description, [which is quoted as Miers, 1886] and its true identity is still uncertain”. Stenorhynchus spinifer is not listed in Ng et al. (2008).

The holotype of S. spinifer Miers, 1885 , is extant in the Natural History Museum, London and was examined for the present study. The condition of the specimen is poor but some morphological characters are discernable. Its assignment to Stenorhynchus Lamarck, 1818 , is considered doubtful as the carapace spinulation compares well with that illustrated by Miers (1886: pl. I, fig. 4) for Achaeopsis spinulosa Stimpson, 1857 from Simon’s Bay, South Africa. This specimen too is extant and was examined. The morphologies of their first male pleopods are similar suggesting that the two specimens described by Miers may be synonymous. Material of Dorhynchus thomsoni Thomson, 1873 , was also examined. All three species look remarkably similar.

The systematics of A. spinulosus and D. thomsoni has been questioned. Rathbun (1925), Barnard (1950), Griffin (1966) and Griffin and Tranter (1986) assigned both species to Achaeopsis Stimpson, 1857 , while Bouvier (1940), Monod (1956), Zariquiey Álvarez (1968), Christiansen (1969), Ingle (1980) and Manning & Holthuis (1981) retained Achaeopsis and Dorhynchus Thomson, 1873 as distinct genera. Moreover, Manning & Holthuis (1981) concluded that the occurrence of D. thomsoni outside the eastern Atlantic required verification. Achaeopsis (type species A. spinulosus Stimpson, 1857 ) and Dorhynchus (type species D. thomsoni Thomson, 1873 ) are placed on the ICZN Official List (Opinion 712). This current study suggests that the systematics of A. spinulosus , S. spinifer and D. thomsoni from the Atlantic should be revisited.

Valid as Stenorhynchus spinifer Miers, 1885 , incertae sedis.