Tropidoptera heliciformis

Tropidoptera heliciformis is a species of small, air-breathing land snail, a terrestrial pulmonate gastropod mollusk in the family Amastridae. ^[3]

Tropidoptera heliciformis
Conservation status
Critically Endangered  (IUCN 2.3)[1]
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Order:	Stylommatophora
Family:	Amastridae
Genus:	Tropidoptera
Species:	T. heliciformis
Binomial name
Tropidoptera heliciformis Ancey, 1890[2]
Synonyms
Amastra heliciformis Ancey, 1890 superseded combination

Description

The length of the shell attains 6 mm, its diameter 10 mm.

(Original description in Latin) The shell is heliciform, depressed, and broadly umbilicate, with the umbilicus open, deep, angular at the margin, and approximately 2 mm in width. The surface is matte, brown, and marked with coarse striations, giving it a somewhat solid appearance.

The spire is depressed and broadly conical with a somewhat obtuse apex. It consists of 5 slightly convex whorls that increase regularly in size and are separated by an impressed suture. The body whorl is carinate, sloping convexly above, fully convex below, and gradually descending over a distance in front.

The aperture is oblique, irregularly circular, and furnished with a sharp, revolving, simple columellar fold. It is emarginate and angular externally, rounding at the base. The margins of the aperture are remote, with the columellar margin straight-sloping and forming an angle with the basal margin. ^[4]

Distribution

This species is endemic to Hawaii, occurring on Oahu.