Powellisetia bilirata
| Powellisetia bilirata | |
|---|---|
| Holotype of Powellisetia bilirata from Auckland War Memorial Museum | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Gastropoda |
| Subclass: | Caenogastropoda |
| Order: | Littorinimorpha |
| Family: | Rissoidae |
| Genus: | Powellisetia |
| Species: | P. bilirata
|
| Binomial name | |
| Powellisetia bilirata (Ponder, 1965)
| |
Powellisetia bilirata is a species of marine gastropod mollusc in the family Rissoidae.[1] First described by Winston Ponder in 1965, it is endemic to the waters of New Zealand.
Description
In the original description, Ponder described Powellisetia bilirata as follows:
Shell minute, small for genus, rather solid, semi-transparent, strongly spirally striate, yellowish brown. Whorls 4, convex, angled by a strong spiral cord in middle of whorl; protoconch of 1½ whorls, finely spirally striate, transparent, apex slightly inrolled. Body whorl rather large, periphery and base rounded. Aperture relatively small, solid, oval angled above; inner lip and columella moderately thickened, concave, columella separated from base below: outer lip weakly channelled above and below, sharp edged, a weak varix behind, and slightly thickened internally. Sculpture of fine, but distinct and regular, spiral threads, the suprasutural and middle cord strong, raised, rather sharp, the latter forming an angle on the whorls, the former being continued over periphery as a strong cord. About 6 fine spirals above, and 6 below middle cord on penultimate, about 16 on base, but these numbers vary slightly in paratypes. Strong cords constant, sometimes disappear over last part of body whorl, but usually continuous. Umbilical chink present but no true umbilicus. Colour pale yellowish-brown, protoconch reddish-brown, Animal, operculum and radula unknown.[2]
P. bilirata has two stronger spirals on its shell, that cross over the whorls at an angle.[3] The species measures 1.05 mm (0.041 in), by 0.68 mm (0.027 in).[4]
Taxonomy
P. bilirata was first described by Winston Ponder in 1965.[2] The holotype is held by the Auckland War Memorial Museum.[5][6]
Distribution
The species is endemic to New Zealand.[1] The holotype was collected by Ken Hipkins on 9 April 1955 from shell sand at McGregors Bay, Whangārei Heads, Northland Region.[7][6] It is found in to the north-east of the North Island, as far north as Manawatāwhi / Three Kings Islands,[8][4] and has been found neat the volcanic Whakaari / White Island.[9]
References
- ^ a b Bieler R, Bouchet P, Gofas S, Marshall B, Rosenberg G, La Perna R, Neubauer TA, Sartori AF, Schneider S, Vos C, ter Poorten JJ, Taylor J, Dijkstra H, Finn J, Bank R, Neubert E, Moretzsohn F, Faber M, Houart R, Picton B, Garcia-Alvarez O, eds. (2022). "Powellisetia bilirata Ponder, 1965". MolluscaBase. World Register of Marine Species. Retrieved 22 November 2022.
- ^ a b Ponder, W. F. (1965). "A Revision of the New Zealand Recent Species Previously Known as Notosetia Iredale, 1915 (Rissoidae, Gastropoda)". Records of the Auckland Institute and Museum. 6: 101–130. ISSN 0067-0464. JSTOR 42906116. Wikidata Q58676804.
- ^ Powell, A.W.B. (1979). New Zealand Mollusca: Marine, Land and Freshwater Shells. Auckland: Collins. p. 99. ISBN 0002169061.
- ^ a b "Powellisetia bilirata". New Zealand Mollusca. Retrieved 22 November 2022.
- ^ Blom, Wilma M. (2025). "Annotated Catalogue of Fossil and Extant Molluscan Types in the Auckland War Memorial Museum". Bulletin of the Auckland Museum. 22. doi:10.32912/BULLETIN/22. ISSN 1176-3213. OCLC 1550165130. Wikidata Q135397912.
- ^ a b "Powellisetia bilirata". Collections Online. Auckland War Memorial Museum. Retrieved 10 November 2025.
- ^ Blom, Wilma M. (2020). "Fossil and Recent molluscan types in the Auckland War Memorial Museum. Part 4: Gastropoda (Caenogastropoda - Neocyclotidae to Epitoniidae). [Cyclophoroidea, Cerithioidea, Littorinimorpha]". Papahou: Records of the Auckland Museum. 55: 101–150. doi:10.32912/RAM.2020.55.7. ISSN 1174-9202. JSTOR 27008995. S2CID 229670783. Wikidata Q106828489.
- ^ "marine snail, Powellisetia bilirata Ponder, 1965". Te Papa. Retrieved 23 November 2022.
- ^ "marine snail, Powellisetia bilirata Ponder, 1965". Te Papa. Retrieved 23 November 2022.