Sheldonia, Ancey, 1887

Herbert, David G., 2017, A new genus and eight new species of tail-wagger snails from eastern South Africa, with a key to genera within Sheldonia s. l. (Gastropoda: Urocyclidae), European Journal of Taxonomy 309, pp. 1-50 : 3

Key to genera within Sheldonia s.l.

1. Epiphallic caecum arising close to penis apex and adjacent to insertion of penial retractor muscle ( Fig. 1A ) ……………………………………………………………………………………………2

– Epiphallic caecum arising nearer to mid-point of epiphallus ( Fig. 1 B–C) …………………………3

2. Flagellum short and stout ( Fig. 1D ); epiphallus short; vas deferens thick, long and convoluted; spermatophore tail plumose ( Fig. 1E );protoconch spirally punctate ……… Ptilototheca Herbert, 2016

– Flagellum longer, divided into distinct f1 and f2 components ( Fig. 1A ); vas deferens slender and relatively short, not convoluted; spermatophore tail with branched spines ( Fig. 1F ), but not plumose; protoconch smooth (rarely spirally lirate), not punctate. ……… Kerkophorus Godwin-Austen, 1912

3. Epiphallic caecum small and globular ( Fig. 1B ); spermatophore tail bifid ( Fig. 1G ) ……………… ………………………………………………………………… Microkerkus Godwin-Austen, 1912

– Epiphallic caecum large, cylindrical and usually curved ( Fig. 1C ); spermatophore tail not bifid …4

4. Protoconch spirally punctate or with numerous, close-set, incised spiral microstriae; nonspinose distal portion of spermatophore tail long, the subterminal region with short, stout projections on both sides ( Fig. 1H , inset) …………………………… Sheldonia s.s. Ancey, 1887

– Protoconch essentially smooth; non-spinose distal portion of spermatophore tail short, lacking lateral projections ( Fig. 1I , arrow) ………………………………………… Selatodryas gen. nov.

This key must be considered provisional and is provided as a guide to the identification of the existing supra-specific taxa within Sheldonia s.l. However, there remain taxa within Sheldonia s.l. that do not fit well into any of these taxa (e.g., Sheldonia monsmaripi Herbert, 2016 and S. wolkbergensis Herbert, 2016 ). Establishing the true relationships of these enigmatic species will require additional insights from molecular data. Furthermore, even within these genera, there is significant variation and future research may reveal that this encompasses additional lineages worthy of recognition as distinct genera, particularly within Kerkophorus and Microkerkus . Construction of a key should thus be viewed as an iterative process, for which this is a first step.

Figures

Fig. 1. Illustrations of characters mentioned in key to genera within Sheldonia s.l. A. Kerkophorus vittarubra sp. nov., epiphallus, caecum and flagellum (paratype, NMSA V4725/T4062). B. Microkerkus burnupi (Godwin-Austen, 1914), epiphallus and caecum (NMSA W3660). C. Sheldonia fingolandensis sp. nov., epiphallus, caecum and flagellum (paratype, NMSA W4169/T3385). D. Ptilototheca soutpansbergensis Herbert, 2016, epiphallus, caecum and flagellum (paratype, NMSA P0304/T4060). E. Ptilototheca soutpansbergensis, spermatophore (paratype, NMSA W2259/T4067). F. Kerkophorus poeppigii (Pfeiffer, 1846), spermatophore (NMSA W4911). G. Microkerkus arnotti (Benson, 1864), spermatophore (NMSA W6082). H. Sheldonia capsula (Benson, 1864), spermatophore, arrow indicates short, stout projections on both sides of the subterminal region of the tail, enlarged in inset (NMSA W4686). I. Selatodryas luteosoma gen. et sp. nov., spermatophore, arrow indicates non-spinose distal portion of tail (paratype, NMSA W9691/T3874).