Gymnobela carinaria

Gymnobela carinaria is an extinct species of sea snail, a marine gastropod mollusk in the family Raphitomidae.^[1]

(Original description) The shell is small and broadly fusiform. It consists of eight whorls, including a smooth, typical protoconch of 2 ½ whorls.

The spire is turriculate and approximately equal in height to the aperture and siphonal canal combined. The whorls are angled at the periphery. This angle is initially situated at the lower third of the second (first post-nuclear) whorl but ascends to just below the midpoint of the penultimate whorl. The suture is impressed and bordered below by a single rounded spiral fold.

The shell sculpture is a combination of closely spaced axial folds and numerous spiral cords:

Axial Folds: There are 17 oblique axial folds on both the penultimate and body whorls. These folds are rounded, closely spaced, and prominent. They are strongly developed only from the periphery down to the lower suture. They slightly crenulate (scallop) the subsutural spiral fold.

Spiral Cords: The cords have linear interspaces.

There are 8 cords on the second post-nuclear whorl and 11 on the penultimate whorl. The five cords above the periphery are finer and less distinct.

Total: Approximately 40 cords cover the body whorl, base, and canal neck.

The aperture is ovate. The siphonal canal is rather short and bent to the left (sinistrally tortuous). (The note that the canal is damaged is observational and not part of the species diagnosis.) ^[2]

Fossils of this marine species were found in Tertiary strata from Motutara, West Coast, Auckland, New Zealand.

• Powell, A. W. B. (1935). "Tertiary Mollusca from Motutara, West Coast, Auckland". Records of the Auckland Institute and Museum. 1: 327–340. ISSN 0067-0464. JSTOR 42905961. Wikidata Q58676576.