Afrodonta pentodon, Herbert, 2020

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, European Journal of Taxonomy 629, pp. 1-55 : 17-19

Afrodonta pentodon sp. nov.

urn:lsid:zoobank.org:act:ED136FF6-F319-4C79-9EBA-B225283F7F6D

Figs 6 , 7 A–D, 17Q–R

Diagnosis

Shell very small, spire distinctly raised; protoconch microscopically shagreened; teleoconch texture silky; sculpture of simple, close-set, microscopic axial riblets; aperture with two well-developed, inrunning parietal lamellae, lower one extending just beyond edge of aperture, upper one recessed a short distance, and a rounded baso-columellar denticle; palatal region with a low, broad, in-running, thickened pad situated well below mid-whorl, plus a small, narrow, deep-set, subsutural denticle; umbilicus narrow to moderate. Shell corneous-brown when fresh; diameter up to 1.5 mm.

Etymology

From the Greek pente (πέντε): five, and odontos (ΟΔΟντΟς): a tooth; with reference to the five apertural teeth.

Material examined

Holotype

SOUTH AFRICA • KwaZulu-Natal, Ngele Forest ; 30.533° S, 29.633° E; 1350 m a.s.l.; 3 Mar. 1997; D.G. Herbert leg.; mistbelt Podocarpus forest, sorted from dried leaf-litter sample; diameter 1.45 mm, height 0.84 mm; NMSA V6950/T4239 .

Paratypes

SOUTH AFRICA • 4 specimens; KwaZulu-Natal, Ngele Forest ; 30.5309° S, 29.6846° E; 1290 m a.s.l.; 3 Mar. 1997; D.G. Herbert leg.; mistbelt Podocarpus forest, in leaf-litter and under logs; NMSA V8275/ T4240 .

Other material

SOUTH AFRICA – KwaZulu-Natal • 1 specimen; Ngele Forest ; 30.53° S, 29.63° E; 1350 m a.s.l.; 17 Feb. 1997; D. Barraclough leg.; mistbelt Podocarpus forest, sorted from leaf-litter; NMSA V4864 • 1 specimen; same collection data as for preceding; 27 Mar. 1998; C. Symes leg.; NMSA V6887 .

Description

Shell very small, diameter up to 1.5 mm, H/D ratio ±0.58; spire distinctly raised; suture indented and apical portion of whorls strongly convex, whorls thus weakly shouldered; periphery more or less at mid-whorl; whorls slightly flat-sided; last adult whorl descendant. Protoconch comprising apical cap plus approx. 0.75 whorl; diameter ±310 μm; microscopically shagreened. Teleoconch of up to 3.25 whorls; surface texture silky; sculpture of simple, close-set, microscopic axial riblets; riblets alternating in strength and with even finer spiral threads in their intervals (sometimes scarcely evident). Umbilicus narrow to moderate.Aperture obliquely lunate, broader basally; parietal region with two well-developed, in-running lamellae, lower one extending just beyond edge of aperture, upper one recessed a short distance and with a flat-topped crest internally; baso-columellar region with a rounded denticle; palatal region with a low, broad, in-running, thickened pad situated well below mid-whorl, plus a small, narrow, deep-set, subsutural denticle. Shell corneous-brown when fresh.

Distribution and conservation

A narrow-range endemic ( Fig. 6 ), known only from Ngele Forest, near Kokstad, KwaZulu-Natal, at 1290–1350 m a.s.l.; living in leaf-litter of southern mistbelt forest. Although this forest is theoretically protected, access is completely uncontrolled and it is surrounded by exotic timber plantation heavily invaded by alien plants.

Remarks

A distinctive species with characteristic dentition, including a thickened palatal pad.

Figures

Fig. 6. Distribution of narrow-range Afrodonta species. Af. geminodonta sp. nov. (purple triangles), Af. mystica sp. nov. (orange square), Af. pentodon sp. nov. (green circles) and Af. unilamellaris Connolly, 1933 (blue circle). Contour at 1000 m.

Fig. 7. Shells of Afrodonta species. A–D. Afrodonta pentodon sp. nov., holotype, diameter 1.45 mm (NMSA V6950/T4239). E–G. Afrodonta unilamellaris Connolly, 1933, Mfongosi, KwaZulu-Natal, diameter 1.52 mm (NMSA A9186).