Lissotestella
Lissotestella is a genus of minute sea snails or micromolluscs, marine gastropod molluscs, unassigned in the superfamily Seguenzioidea. First described by A. W. B. Powell in 1946, the genus is endemic to the waters surrounding New Zealand.
Description
In the original description, Powell described the genus as below:
The genus' protoconch is bluntly rounded, having approximately 1.5 smooth whorls, and typically has a slight ledge within its peristome, and a rounded variciform swelling found behind the outer lip. Members of the genus are turbiniform and narrowly umbilicate. The protoconch is large, swollen, dome-shaped, with a sculpture of fine anastomosing ridges. The genus has convex teleoconch whorls that are sculptured with either spiral cords or lirae. Members of the genus have heights that vary between.
The genus can be differentiated from Lissotesta due to Lissotestella having stronger umbilicus spirals, and the presence of a varix on the outer lip.
Taxonomy
Lissotestella was first described by Baden Powell in 1946, naming Lissotestella tenuilirata as the type species. The genus was previously placed in the family Skeneidae, and in 2002, in the former taxonomic order Archaeogastropoda by Jack Sepkoski. In 2009, the genus was placed within the superfamily Seguenzioidea as a "plausible member" of the group, with the genus remaining unassigned within the superfamily. Holotypes of two species of Lissotestella are held by the Auckland War Memorial Museum, two by the Canterbury Museum, one by the Natural History Museum, London, and one by Te Papa.
Distribution
Lissotestella is endemic to New Zealand, with fossils dating back likely to the Kaiatan stage of the Eocene. While L. tenuilirata has a wide distribution across New Zealand waters, including the Auckland Islands, and Chatham Islands, many members are only known to occur in restricted ranges, including L. caelata near Manawatāwhi / Three Kings Islands, L. cookiana in the Cook Strait, L. tryphenensis near Great Barrier Island, and L. rissoaformis in the Auckland Islands.
Species within the genus Lissotestella include: