Pseudexomilus caelatus

Pseudexomilus caelatus
Holotype of Pseudexomilus caelatus from Auckland War Memorial Museum
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Subclass:	Caenogastropoda
Order:	Neogastropoda
Family:	Horaiclavidae
Genus:	Pseudexomilus
Species:	P. caelatus
Binomial name
Pseudexomilus caelatus A.W.B. Powell, 1944

Pseudexomilus caelatus is an extinct species of marine gastropod mollusc in the family Horaiclavidae. ^[1] Fossils of the species date to the middle Miocene, and are found in Adelaide, South Australia.

Description

View of reverse side of holotype

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

Protoconch of 2½ whorls, tip bluntly rounded, smooth, following whorls much larger, strongly convex, radially ribbed, 13 radials per whorl. Post-nuclear whorls with strong, flat-topped, sharply raised wavy cords, four on first whorl, six on fourth whorl, nine on penultimate and twenty-two on body-whorl, nine of which are on the anterior end. Axials obsolescent, irregularly but weakly developed throughout, about ten per whorl. Aperture (better shown in paratype) quadrangular. Outer lip not thickened, but lirate within. Anterior canal short, subtubular, not sinused. Anal sinus as described above. ^[2]

The holotype of the species measures 11.6 mm (0.46 in) in height and 3.9 mm (0.15 in) in diameter. ^[2]

Taxonomy

P. caelatus was first described by A.W.B. Powell in 1944, who named it the type species of the genus Pseudexomilus . ^[2] The holotype was collected by W. Howchin and J. C. Verco in 1919 from the Metropolitan Abattoirs Bore in Adelaide, Australia, and is held by the Auckland War Memorial Museum. ^{[3] [4]}

Distribution

This extinct marine species occurs in middle Miocene (Bairnsdalian) strata of the lower Dry Creek Sand, at a depth of between 122–152 m (400–499 ft), in Adelaide, South Australia. ^{[3] [5]}

References

1. "Pseudexomilus caelatus A. W. B. Powell, 1944 †". WoRMS. World Register of Marine Species . Retrieved 10 November 2025.
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. 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.
4. "Pseudexomilus caelatus". Collections Online. Auckland War Memorial Museum . Retrieved 10 November 2025.
5. 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.

Further reading

• Ludbrook, N. H. (1958). "The molluscan fauna of the Pliocene strata underlying the Adelaide plains. Part V-Gastropoda (Eratoidae-Scaphandridae)". Transactions of the Royal Society of South Australia, Incorporated. 81: 98.