Thoristella chathamensis cookiana

Taxobox
name = "Thoristella chathamensis cookiana"
status =
regnum = Animalia
phylum = Mollusca
classis = Gastropoda
subclassis = Prosobranchia
ordo = Archaeogastropoda
superfamilia = Trochacea
familia = Trochidae
genus = "Thoristella"
species = "T. chathamensis"
subspecies = "T. chathamensis cookiana"
trinomial = "Thoristella chathamensis cookiana"
trinomial_authority = Powell, 1934

"Thoristella chathamensis cookiana" is a subspecies of very small sea snail, a marine gastropod mollusc in the family Trochidae, the top snails or top shell.

Distribution

This subspecies is endemic to New Zealand, around the south of the North Island and the north of the South Island.

Habitat

These top snails are found under rocks at low tide.

hell description

The shell is of light build, with a low, broadly convex spire, obsolete shoulder, and no peripheral flange. The shell sculpture consists of numerous fine regular spiral cords, about 7 on the penultimate, and 29 on the body whorl and base.

The shell coloration is greenish-buff, the upper surface with radial dark grey maculations, and the base with the spiral cords either lined continuously, or intermittently, with dark grey.

The shell height is up to 4 mm, and width up to 6 mm.

References

* Powell A. W. B., "New Zealand Mollusca", William Collins Publishers Ltd, Auckland, New Zealand 1979 ISBN 0-00-216906-1