Phialodonta introtuberculata, gen. et comb. nov.
Creators: name: Herbert, David G.
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Stylommatophora
Charopidae
Phialodonta
Phialodonta introtuberculata

description: Phialodonta introtuberculata (Connolly, 1933) gen. et comb. nov.
Figs 14, 16 A–D, 19G–H
Afrodonta introtuberculata Connolly, 1933: 147, text-fig. 1(9), pl. 7, figs 5–8.
Afrodonta introtuberculata – Connolly 1939: 255, text-fig. 19(9). — Solem 1970: 361. — Herbert & Kilburn 2004: 247, text-fig.
Diagnosis
Shell relatively large, narrowly planorboid, spire slightly sunken; protoconch initially smooth, becoming microscopically shagreened and finally with low axial undulations (diameter ±350 μm); teleoconch sculptured by relatively strong, close-set, compound axial riblets, intervals between riblets with 3–4 microscopic axial threads; spiral sculpture scarcely evident even in umbilicus; parietal and basocolumellar dentition lacking; palatal region with 1–3 axially aligned pairs of denticles set back ⅛ to ½ whorl behind outer lip, outermost pair usually visible through aperture, the others apparent only through translucent shell; lower denticle well below periphery, upper one slightly above periphery; number and position of denticle pairs somewhat variable and related to degree of development; umbilicus shallow and very wide. Shell translucent, honey-brown when fresh; diameter up to 2.0 mm.
Material examined
Holotype SOUTH AFRICA • KwaZulu-Natal, Nottingham Road; prior to 1928; A.J. Taynton leg.; NHMUK 1931.6.4.1.
Paratypes SOUTH AFRICA • 3 specimens; same collection data as for holotype; NHMUK 1937.12.30.2759 to 2761.
Other material
SOUTH AFRICA – KwaZulu-Natal • 4 specimens; Karkloof, Mbona Private Nat. Res., Holbeck; 29.3009° S, 30.3615° E; 1300 m a.s.l.; 22 Jun. 2002; D.G. Herbert leg.; mistbelt Podocarpus forest, in leaf-litter; NMSA W216 • 1 specimen; Karkloof, Mbona Private Nat. Res., Holbeck area; 29.30119° S, 30.35899° E; 1400 m a.s.l.; 25 Apr. 2004; D.G. Herbert leg.; mistbelt Podocarpus forest, in leaf-litter; NMSA W1810 • 3 specimens; Karkloof, Mbona Private Nat. Res., Holbeck; 29.30339° S, 30.36525° E; 1330 m a.s.l.; 24 Oct. 2004; D.G. Herbert leg.; mistbelt Podocarpus forest, in leaf-litter; NMSA W2438 • 1 specimen; Karkloof, Leopard’s Bush; 29.3183° S, 30.2580° E; ca 1350 m a.s.l.; 23 Nov. 1998; D.G. Herbert, M. Seddon and P. Tattersfield leg.; mistbelt Podocarpus forest, in leaf-litter; NMSA V8417 • 3 specimens; Karkloof Nat. Res.; 29.30° S, 30.23° E; 1 Dec. 2003; A. Moussalli and D. Stuart-Fox leg.; mistbelt Podocarpus forest, in leaf-litter; NMSA W3789 • 7 specimens; Nottingham Road; 29.358° S, 29.995° E; ca 1500 m a.s.l.; pre-1928; A.J. Taynton leg.; NMSA A9191 • 46 specimens; same collection data as for preceding; NMSA A9192 • 3 specimens; same collection data as for preceding; NMSA A9193 • 6 specimens; same collection data as for preceding; NMSA A9221.
Distribution and conservation
A narrow-range endemic (Fig. 14), known only from the Karkloof–Nottingham Road area in the KwaZulu-Natal Midlands, at 1300–1500 m a.s.l.; in leaf-litter of southern mistbelt forest. Judging by the numbers of specimens in the original samples collected by A.J. Taynton in the Nottingham Road area (pre-1928), the species may be locally common or abundant. There are a number of provincial and private nature reserves in this area in which the species has been collected in recent years.
Remarks
Phialodonta introtuberculata gen. et comb. nov. is distinguished from other species in the genus by its much flatter shell and paired palatal dentition. Afrodonta geminodonta sp. nov. has similar sets of paired palatal denticles, but its spire is raised, the axial sculpture much finer and the umbilicus much narrower.
Specimens somewhat resembling P. introtuberculata gen. et comb. nov. have been found in the Creighton area (Hlabeni Forest, 29.975° S, 29.742° E, NMSA V5219). However, although they have similar palatal dentition, their axial sculpture is noticeably finer, the umbilicus not as wide and they are milky-white in colour.
description: Published as part of Herbert, David G., 2020, Revision of the aperturally dentate Charopidae (Gastropoda: Stylommatophora) of southern Africa - genus Afrodonta s. lat., with description of five new genera, twelve new species and one new subspecies, pp. 1-55 in European Journal of Taxonomy 629 on pages 42-44, DOI: 10.5852/ejt.2020.629, http://zenodo.org/record/3762280