Tubbreva exigua

Tubbreva exigua
Holotype
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Subclass:	Caenogastropoda
Order:	Littorinimorpha
Superfamily:	Cingulopsoidea
Family:	Cingulopsidae
Genus:	Tubbreva
Species:	T. exigua
Binomial name
Tubbreva exigua (Ponder, 1965)
Synonyms [1]
Rufodardanula exiguaPonder, 1965 Rufodardanula (Tubbreva) exiguaPonder, 1965

Tubbreva exigua is a species of minute sea snails, marine gastropod molluscs belonging to the family Cingulopsidae. ^[1] First described by Winston Ponder in 1965, the species is endemic to New Zealand, primarily found in mid and lower tidal margins of the country.

Description

In the original description, Ponder described the genus as below:

Shell minute, thin, fragile, smooth, red-brown, elongate-conic, imperforate. Whorls 4¼, weakly convex, protoconch dark red-brown, smooth, small, not distinctly marked off. Sutures false-margined by a dark, red-brown, narrow band; body whorl not swollen, periphery and base rounded. Aperture rather large, angled above and below, peristome thin, continuous, a thin glaze across parietal wall. Columella vertical, with a faint swelling above. In holotype and majority of specimens encountered outer lip thin, fragile, very slightly excavated, though occasional shells show some thickening of entire peristome. Colour reddish-brown on spire, a pale brown, indistinct band in middle of body whorl, periphery and base reddish-brown, darker below sutures and in umbilical area. Variation in size, shape, and convexity of whorls considerable. Though superficially similar to the deepwater R. minitula, that species differs in having a blunter protoconch, nearly flat whorls, and a rounded aperture. R. exaltata differs in its larger size, broader spire and heavier shell. ^[2]

The species' shell is similar in appearance to Skenella spadix , but has a taller spire, whorls that are less convex. ^[3] The holotype of the species measures 0.1 mm (0.0039 in) in height, with a width of 0.575 mm (0.0226 in). ^[2]

Taxonomy

The species was first described by Winston Ponder in 1965 as Rufodardanula (Tubbreva) exigua, the type species of the subgenus Rufodardanula (Tubbreva). ^[2] The holotype was collected by W.R.B. Oliver on 4 September 1910 from brown weeds in rock pools east of Purau, Lyttelton Harbour, and is held by the Auckland War Memorial Museum. ^{[4] [5]} In 1980, Tubbreva was raised to genus level by Ponder and E. K. Yoo, making the species the type species for the genus, and leading to the currently accepted name Tubbreva exigua. ^[6]

Distribution and habitat

T. exigua is endemic to New Zealand, found in the waters surrounding the mainland, as Manawatāwhi / Three Kings Islands, the Chatham Islands and the New Zealand Subantarctic Islands. ^[7] The species more commonly lives at mid- and lower tidal levels. ^[8]

References

1. Tubbreva exigua (Ponder, 1965) . Retrieved through: World Register of Marine Species  on 4 November 2025.
2. Ponder, W. F. (1965). "The Family Eatoniellidae in New Zealand". Records of the Auckland Institute and Museum . 6: 47–99. ISSN   0067-0464. JSTOR   42906115. Wikidata   Q58676802.
3. Powell, A.W.B. (1979). New Zealand Mollusca: Marine, Land and Freshwater Shells. Auckland: Collins. p. 117. ISBN   0002169061.
4. 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. Wikidata   Q135397912.
5. "Tubbreva exigua". Collections Online. Auckland War Memorial Museum . Retrieved 4 November 2025.
6. Ponder, W. F.; Yoo, E. K. (1980). "A review of the genera of the Cingulopsidae with a revision of the Australian and tropical Indo-Pacific species (Mollusca: Gastropoda: Prosobranchia)". Records of the Australian Museum. 33 (1): 1–88. doi:10.3853/J.0067-1975.33.1980.275. ISSN   0067-1975. Wikidata   Q92172951.
7. "Tubbreva exigua (Ponder, 1965)". New Zealand Mollusca. Retrieved 4 November 2025.
8. Morley, Margaret S.; Hayward, Bruce W. (2010). "Tidal Zonation of Ostracod and Micromolluscan Faunas in Coralline Turf on the East and West Coasts of Auckland, New Zealand" (PDF). Papahou: Records of the Auckland Museum . 47: 51–74. ISSN   1174-9202. JSTOR   42905912. Wikidata   Q58623372.