Splendrillia formosa

Splendrillia formosa Temporal range: middle 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:	Drilliidae
Genus:	Splendrillia
Species:	†S. formosa
Binomial name
†Splendrillia formosa A. W. B. Powell, 1944

Splendrillia formosa is an extinct species of sea snail, a marine gastropod mollusc in the family Drilliidae. ^[1] Fossils of the species date to the middle Miocene, and occur in the strata of the Otway Basin of Victoria, Australia.

Description

Reverse view of holotype

In the original description, Powell described the species as follows:

Shell small, slender, tall-spired, sculptured with narrowly-rounded, very oblique axials, 10-11 per whorl, obsolescent on last whorl. Surface covered with incised spirals, 12 on spire-whorls and about 26 on body-whorl, base, and neck. From the middle of the base to the anterior end the spirals become increasingly deeper and wider-spaced, cutting the surface into quite strong rounded cords. Subsutural fold weak, narrow, and flattened. Shoulder very steep, broad, and very shallow, scarcely indenting the lightly convex whorl outlines. Aperture narrow; parietal callus-pad heavy; posterior sinus deep, subtubular. ^[2]

The holotype of the species measures 10.5 mm (0.41 in) in height and 3.9 mm (0.15 in) in diameter. ^[2] The species' developed spiral sculpture resembles Iredalea exilis , but can be distinguished due to lacking a keeled protoconch. ^[3]

Taxonomy

The species was first described by A.W.B. Powell in 1944. ^[2] The holotype was collected from Clifton Bank, Hamilton, Victoria, at an unknown date prior to 1944, and is held by the Auckland War Memorial Museum. ^{[4] [5]}

Distribution

This extinct marine species dates to the middle Miocene, and occurs in the strata of the Otway Basin of Victoria, Australia, known from the Muddy Creek Formation. ^{[4] [6]}

References

1. Splendrillia formosa A. W. B. Powell, 1944 † . 24 November 2025. Retrieved through: World Register of Marine Species .
2. Powell, A. W. B. (1944). "The Australian Tertiary Mollusca of the Family Turridae". Records of the Auckland Institute and Museum . 3: 3–68. ISSN   0067-0464. JSTOR   42905993. Wikidata   Q58676624.
3. dei Musei, Via; Selmi, Via (2005). "Notes on fossil turrids 1 (Mollusca: Gastropoda). Elaeocyma dertonensis, new name for Drillia exilis Bellardi, 1877 not Pease, 1868". Bollettino malacologico. 41 (5–8): 13-16.
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. OCLC   1550165130. Wikidata   Q135397912.
5. "Splendrillia formosa". Collections Online. Auckland War Memorial Museum . Retrieved 24 November 2025.
6. Darragh, Thomas A. (August 2024). "A checklist of Australian marine Cenozoic Mollusca". Memoirs of Museum Victoria . 83: 37–206. doi:10.24199/J.MMV.2024.83.02. ISSN   1447-2546. Wikidata   Q136396722.