Antisolarium egenum
A small marine snail endemic to New Zealand.
Antisolarium egenum is a marine gastropod mollusc from the family Trochidae, commonly known as top shells. This small sea snail is endemic to New Zealand.
The thin, minute shell ranges from 4 mm to 7.5 mm in size. It has a low, ovate-conic shape and is widely umbilicated. The shell is ashy white, with a pearly underside. There are six convex whorls, and the body whorl is obtusely angular. Each whorl is encircled by four sharply compressed, well-elevated ribs; the two uppermost ribs are beaded. The spaces between the ribs are concave and smooth, with a single groove near the margin of the umbilicus. The umbilicus occupies about a third of the base, is tunnel-shaped, and reaches the apex. Its sides are excavated on each whorl, and the rim is crenulated. The aperture is nearly circular, slightly indented by the inflection of the columella, and its interior is pearly. The lip is simple.
Quick Facts
- Taxon
- Antisolarium egenum
Facts from the source article.
Lore & Background
The shell of Antisolarium egenum is thin and minute, with a low ovate-conic shape and an ample umbilicus. Its color is ashy white, pearly beneath. The shell has six convex whorls, with the body whorl obtusely angular. Each whorl is encircled by four sharply-compressed, well-elevated ribs, the two uppermost of which are beaded. The interspaces are concave and smooth, with a single groove near the margin of the umbilicus. The umbilicus is tunnel-shaped, occupies a third of the base, and penetrates to the apex; its sides are excavated on each whorl, and the verge is crenulated. The aperture is nearly circular, slightly encroached upon by the inflection of the columella, and its interior is pearly. The lip is simple.
Reader's Guide
Antisolarium egenum is a marine gastropod mollusc in the family Trochidae, known as top shells. Its description in the source article provides detailed morphological characteristics, including shell size, shape, color, and ornamentation. The species is noted as endemic to New Zealand, indicating its restricted geographic distribution. The article references works by Powell (1979) and Herbert (1992), situating it within broader malacological literature. The shell's features—such as the beaded ribs, concave interspaces, and tunnel-shaped umbilicus—are diagnostic for identification. As a member of Trochidae, it shares the family's typical pearly interior and simple lip. The species' small size and endemic status contribute to its interest for collectors and researchers studying New Zealand's marine biodiversity.
Did You Know?
- The shell size varies between 4 mm and 7.5 mm.
- This marine species is endemic to New Zealand.
Frequently Asked Questions
What is Antisolarium egenum?
It is a tiny sea snail belonging to the top shell family (Trochidae) that occurs only in New Zealand waters.
How large does Antisolarium egenum grow?
The shell is quite small, measuring between 4 and 7.5 millimeters across.
What does Antisolarium egenum's shell look like?
It has a low, egg-shaped conical form with six rounded whorls, an ashy-white exterior, and a pearly interior. Each whorl carries four raised ribs, the top two of which are beaded.
Where can Antisolarium egenum be found?
This species is endemic to New Zealand, meaning it occurs nowhere else in the world.
What is special about Antisolarium egenum's umbilicus?
The central opening is tunnel-like and takes up roughly a third of the shell's base, extending all the way through to the tip.
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