Latouchella costata

Overview

Latouchella costata was a Cambrian mollusk known from a small, laterally flattened, coiled shell. Its broad lateral folds and smooth dorsal surface can be examined in turn.^[1]

Key facts

Type specimen SM A780 was described as having a maximum shell length of about 3 mm. Even in such a tiny shell, coiling direction, aperture shape, and lateral folds can be compared separately.^[1]

Time and place

It is an early Cambrian fossil. The type specimen came from the Comley Limestone in present-day Shropshire, England, United Kingdom. Type specimen SM A780 and the designated comparative specimen, paratype SM A436, were recorded from different horizons.^[1]

The time range describes source context, not the complete duration of this species.

Size, form and skeleton

The type specimen’s shell makes approximately one whorl and has an elongated oval aperture. Broad lateral folds fade away without crossing the dorsal surface. The apex at the initial end lies slightly off the plane of symmetry.^[1]

Habitat and reproduction

Traces of the small shell came from different layers of the Comley Limestone. Type specimen SM A780 came from Ac2, while the associated designated comparative specimen SM A436 came from Ac5. Even within one area, the particular layer of discovery can be traced.^[1]

Fossil discovery

Gubanov and Peel restudied the species in 1998 after Cobbold described it in 1921. They refined the initial description by examining the name-bearing specimen alongside a separate comparative specimen.^[1]

References

1. Redescription of the type species of Latouchella Cobbold, 1921 (Mollusca) from the Lower Cambrian of Comley, England
2. Li et al. — Cambrian molluscs of China’s Xinji Formation
3. Gubanov·Peel (1998) — Restudy of the reference specimen of Latouchella from Comley

Research questions

Interpretations of the front and back of this small shell were linked to research on relationships among early mollusks. The 1998 paper examined Latouchella’s classification by comparing differing interpretations from several researchers.^[1]

Observation

The illustration is based on the internal shell form and remaining recrystallized shell of SM A780. Look for where folds extending from the sides toward the dorsal surface disappear.^[1]