Cryptoborsonia pleurotomella

Cryptoborsonia pleurotomella
Holotype
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Subclass:	Caenogastropoda
Order:	Neogastropoda
Superfamily:	Conoidea
Genus:	† Cryptoborsonia
Species:	†C. pleurotomella
Binomial name
†Cryptoborsonia pleurotomella A. W. B. Powell, 1944

Cryptoborsonia pleurotomella is an extinct species of sea snail, a marine gastropod mollusk, in the superfamily Conoidea, currently unassigned to a family. ^[1] Dating to the middle Miocene, fossils of the species have been found in the Otway Basin and Port Phillip Basin of Victoria, Australia.

Description

Reverse view of holotype

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

Small, biconic, whorls weakly shouldered above middle, aperture half height of shell. Protoconch relatively large, papillate, of two smooth, rounded whorls. Post-nuclear sculpture of wide-spaced, weak, narrow, spiral cords, 4 from shoulder angle to lower suture and 18 on the body-whorl. There are three very weak spiral lirations on the shoulder. Weak axials from the shoulder angle to the lower suture on the first 2½ post-nuclear whorls. Sinus occupying the shoulder, rather deep, arcuate, drawn forwards at the suture and produced forwards below in a broad arcuate sweep. Outer lip thin. Pillar with a median twist-like ridge.. ^[2]

The holotype measured 10 mm (0.39 in) in height and 4.5 mm (0.18 in) in diameter. ^[2]

Taxonomy

The species was first described by A. W. B. Powell in 1944, in the same paper where he described the genus Cryptoborsonia . ^[2] The holotype is held by the Auckland War Memorial Museum. ^[3]

Distribution

C. pleurotomella is found in the Muddy Creek Formation of the Otway Basin in Victoria, and the Gellibrand Formation of the Port Phillip Basin, dating to the middle Miocene. ^[4] The type location for the species is Balcombe Bay / Jullul Bay. ^[2]

References

1. Cryptoborsonia pleurotomella A. W. B. Powell, 1944 † . Retrieved through: World Register of Marine Species  on 29 September 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. 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.