Splendrillia formosa

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.

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

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]