Alvania anabaptizata
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| Alvania anabaptizata | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Gastropoda |
| Subclass: | Caenogastropoda |
| Order: | Littorinimorpha |
| Superfamily: | Rissooidea |
| Family: | Rissoidae |
| Genus: | Alvania |
| Species: | †A. anabaptizata |
| Binomial name | |
| †Alvania anabaptizata O. Boettger, 1907 | |
| Synonyms[1] | |
| |
Alvania anabaptizata is an extinct species of minute sea snail, a marine gastropod mollusc or micromollusk in the family Rissoidae.[1]
The shell is minute, reaching a height of approximately 3.5 mm and a maximum diameter of about 2.1 mm. It is conical-ovate and slightly inflated, with a moderately high, conical spire and a sharp apex. The shell consists of seven slightly convex whorls, separated by a distinctly channelled suture.[2]
The sculpture is cancellate, formed by compressed, nearly straight axial ribs that become weaker toward the base, numbering about 18–22 on the last whorl. These are intersected by fine spiral threads, which are fewer in number and form nodules at the points of intersection. The penultimate whorl bears about five to six spiral threads, increasing to eight or nine on the last whorl. The last whorl is slightly inflated, nearly equalling the spire in height, and may occasionally bear a varix on its mid-portion.[2]
The aperture is rounded-ovate and bordered externally by a strong varix. The inner lip is smooth to very weakly denticulate but usually shows a distinct thickening.[2]
Distribution
Fossils of this species are known from Middle Miocene deposits in the Banat region of western Romania. The type locality is Kostej (modern Coșteiu), where the species was reported as very common, particularly from the localities Valea Semini and Valea Cășilor. Additional material was recorded from Pârâul Ungurului, where it is less frequent, and from Lăpuș, represented by fewer specimens.[2]