Chelifer Geoffroy, 1762

Judson, Mark L. I., 2012, Nomenclatural problems associated with the generic names Obisium Leach, 1814, Blothrus Schiödte, 1847 and Neobisium Chamberlin, 1930 (Arachnida: Chelonethi), Zootaxa 3475, pp. 21-35 : 22

Synonymy between Chelifer Geoffroy, 1762 and Obisium Illiger, 1792

Illiger (in Kugelann & Illiger 1798, p. 501) proposed the new generic name Obisium for Acarus cancroides Linnaeus, 1758 (as Scorpio cancroides (Linnaeus, 1758)) and Scorpio cimicoides Fabricius, 1793 . No diagnosis was provided, but the inclusion of these two species is a sufficient indication to make Obisium Illiger, 1798 an available name (Article 12.2.5). Illiger (1807, p. 221) later explained that the spelling “ Obisium ” was an error for Opisium and that this name had been proposed as a replacement for Chelifer Geoffroy, 1762 :

“Nomen genericum Chelifer minus aptum, quoniam adiectuum est, cum nomine Opisium commutaui, quod incessui retrogrado horum insectorum alludit. Obisium , quod cel Latreille scripsit, erroneum est, nomen enim ab οπισω, retro, deduxi.” [Because the generic name Chelifer is less suitable, being an adjective, it was changed to Opisium, which alludes to the retrograde gait of these insects. Obisium , as Latreille wrote it, is erroneous, the name being derived from οπισω, backwards.]

There is no internal evidence of this error in Kugelann & Illiger (1798); examination of the typography shows that Obisium is indeed written with a ‘b’ rather than an inverted ‘p’. Opisium Illiger, 1807 is therefore an unjustified emendation of Obisium Illiger, 1798 and its junior objective synonym (Article 33.2.3). It is not clear why Illiger (1807) only referred to Latreille’s (1804a) use of ‘ Obisium ’, but perhaps he had not noticed that Opisium was misprinted in his own work. Illiger’s (1807) correction has generally been overlooked or ignored by subsequent authors, except Kew (1911). Obisium Illiger, 1798 was placed on the Official List of Rejected and Invalid Names in Zoology by Opinion 1542 (International Commission on Zoological Nomenclature 1989), as a junior objective synonym of the conserved name Chelifer Geoffroy, 1762 . Illiger (1798) did not indicate a type species for Obisium and, because he did not mention Chelifer in that work, the provisions of article 67.8 of the Code (concerning type species of nominal genus-group taxa denoted by new replacement names) do not apply. The first valid designation of a type species appears to be that of Westwood (1836), who stated that Acarus cancroides was the type species of both Obisium and Chelifer . Harvey (1991) considered that Chamberlin (1930) had been responsible for designating A. cancroides as the type of Obisium Illiger, 1798 , but Chamberlin simply stated (erroneously) that this was the only species included in Obisium by Illiger (1798).