Sheldonia Ancey, 1887

Herbert, David G., 2016, New narrow-range endemic land snails from the sky islands of northern South Africa (Gastropoda: Streptaxidae and Urocyclidae), European Journal of Taxonomy 236, pp. 1-29 : 15-16

Genus Sheldonia Ancey, 1887 (sensu lato)

Sheldonia Ancey, 1887: 53 . Type species: Helix trotteriana Benson, 1848 , by subsequent designation ( Connolly 1925: 467).

Peltatus Godwin-Austen, 1908: 131 . Type species (original designation) Helix hudsoniae (non Benson, 1864) Godwin-Austen, 1908 [= Vitrina huttoniae var. aloicola Melvill & Ponsonby, 1890 , cf. Godwin- Austen 1912].

Sheldonia is currently a poorly understood and ill-defined genus that has been used sensu lato for an assemblage of heliciform urocyclids occurring in southern Africa. Unpublished anatomical and molecular studies clearly show that it is a composite entity comprising several distinct, monophyletic lineages that warrant recognition as distinct genus-level entities. In Sheldonia s.s. the epiphallus is of moderate length, the epiphallic caecum is elongate and arises close to or just distal to the mid-region of the epiphallus, the flagellum is long and divided into distinct F1 and F2 components, the atrium frequently possesses a stimulator and the free oviduct gland is conspicuously enlarged. There is no penial verge or atrial diverticulum and the vas deferens is not thickened and convoluted. In addition, the protoconch is usually punctate.

The above is largely in accordance with the description of the genus given by Schileyko (2002), except that he stated that the penial retractor muscle was attached to the summit of the caecum when in reality it is attached to the penis apex. This discrepancy stems from the figure of the reproductive tract of S. hudsoniae provided by Godwin-Austen (1908) and was corrected in a subsequent paper (Godwin- Austen 1912) in relation to this species and several others, including the type species. Following Connolly (1939), Schileyko (2002) treated Kerkophorus Godwin-Austen, 1912 and Microkerkus Godwin-Austen, 1912 as synonyms of Sheldonia , but ongoing studies indicate that this is an oversimplification. Further discussion of this is beyond the scope of the present contribution, but the morphological characters diagnostic of these taxa will be provided, together with a key, in a subsequent publication.

The following two species clearly do not belong to Sheldonia s.s., nor are they clearly referable to either Kerkophorus or Microkerkus . Their position relative to other southern African helicoid urocyclids is unclear and for the time being I refer them to Sheldonia in its broadest sense. Clarification of their affinities must await analysis of molecular data.