Afrodonta Melvill & Ponsonby, 1908

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 : 4

Genus Afrodonta Melvill & Ponsonby, 1908

urn:lsid:zoobank.org:act:4D5FE370-F963-46B2-9D66-0D999661727C

Afrodonta Melvill & Ponsonby, 1908: 133 .

Type species

Afrodonta bilamellaris Melvill & Ponsonby, 1908 , by subsequent designation ( Burnup 1912: 335).

Diagnosis

Shell very small (max. diameter ± 1.8 mm), discoidal to lenticular or almost subglobose; spire slightly to moderately raised; umbilical width narrow to moderate; whorl depth variable and whorls not conspicuously tightly coiled; periphery rounded to somewhat flat-sided, close to mid-whorl; last adult whorl sometimes descendant prior to aperture. Protoconch smooth or microscopically shagreened, with neither axial nor spiral sculpture, but sometimes with a slight subterminal swelling, comprising 0.67– 0.75 whorls beyond apical cap; teleoconch surface texture silky with a sculpture of simple, close-set, microscopic axial riblets of alternating strength, often with even finer spiral threads in their intervals. Aperture lunate; apertural dentition very variable.

Remarks

Afrodonta comprises a relatively distinct group characterised by the almost smooth protoconch sculpture and silky teleoconch surface consisting of simple riblets of alternating strength. However, shell profile and apertural dentition exhibit considerable variation.

Some basic observations on the external anatomy and radula of the type species and of Af.novemlamellaris were provided by Godwin-Austen (in Melvill & Ponsonby 1908) and Connolly (1925, 1939), respectively. A peripodial groove is present, but a caudal gland is not evident. The radula formula is (6–7)+ (8–9)+1+(8–9)+(6–7), with tricuspid central and lateral teeth, and somewhat pectinate marginals. The jaw is composed of narrow plates set side-by-side (stegognathous). In 1925, Connolly also described and illustrated the pallial anatomy of Af. novemlamellaris , noting that the ureter was reflected and included a secondary component running parallel to the rectum. Solem (1970) later commented that the presence of a secondary ureter and the configuration of the heart and kidney set Afrodonta apart from Pacific Island endodontids, which lack a secondary ureter.