Mauidrillia imparilirata

Mauidrillia imparilirata Temporal range: early Miocene PreꞒ Ꞓ O S D C P T J K Pg N
Holotype from Auckland War Memorial Museum
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Subclass:	Caenogastropoda
Order:	Neogastropoda
Family:	Horaiclavidae
Genus:	Mauidrillia
Species:	†M. imparilirata
Binomial name
†Mauidrillia imparilirata A. W. B. Powell, 1942

Mauidrillia imparilirata is an extinct species of sea snail, a marine gastropod mollusc in the family Horaiclavidae. ^[1] Fossils of the species date to the early Miocene strata of the Pakaurangi Formation, and are found at Pakurangi Point on the Kaipara Harbour, Northland, New Zealand, and in the southwestern Waikato Region.

Description

Reverse view of holotype

The species has a smaller shell and shorter canal than Mauidrillia inaequalis , with carinate axials at the peripheral angle. The shells have 5.5 whorls, including a protonconch of 1.5 whorls that do not extend to the upper suture. The spirals are very weak on the shoulder, but crisp below. ^[2] The holotype of the species measures 6.8 mm (0.27 in) in height and 3.0 mm (0.12 in) in diameter. ^[2]

Taxonomy

The species was first described by A.W.B. Powell in 1942. ^[2] The holotype was collected from the Target Gully Shellbed at Glen Creek, Oamaru, Otago, New Zealand at an unknown date prior to 1943, and is held by the Auckland War Memorial Museum. ^{[3] [4]}

Distribution

This extinct marine species occurs in early Miocene strata of the Pakaurangi Formation at Pakurangi Point on the Kaipara Harbour, Northland, New Zealand. ^[3] It is also known from blue mudstone strata in the Awakino Gorge. ^{[2] [5]}

References

1. Mauidrillia imparilirata A. W. B. Powell, 1942 † . 8 December 2025. Retrieved through: World Register of Marine Species .
2. Powell, A. W. B. (1942). "The New Zealand recent and fossil Mollusca of the family Turridae, with general notes on Turrid nomenclature and systematics". Bulletin of the Auckland Institute and Museum . 2: 86. ISSN   0067-0456. OCLC   1826451. Wikidata   Q115110377.
3. 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.
4. "Mauidrillia imparilirata". Collections Online. Auckland War Memorial Museum . Retrieved 8 December 2025.
5. Fleming, C. A. (March 1972). "Type localities of otaian Gastropoda from Awakino (N91)". New Zealand Journal of Geology and Geophysics . 15 (1): 177–178. doi:10.1080/00288306.1972.10423957. ISSN   0028-8306. Wikidata   Q123258397.

Further reading

• P. A. Maxwell. 1988. Late Miocene Deep-Water Mollusca from the Stillwater Mudstone at Greymouth, Westland, New Zealand: Paleoecology and Systematics. New Zealand Geological Survey Paleontological Bulletin 55
• Maxwell, P.A. (2009). Cenozoic Mollusca. pp. 232–254 in Gordon, D.P. (ed.) New Zealand inventory of biodiversity. Volume one. Kingdom Animalia: Radiata, Lophotrochozoa, Deuterostomia. Canterbury University Press, Christchurch