Billingsella costata

Overview

Billingsella costata is a brachiopod with a transversely broad shell bearing strong ridges. You can examine the forms and surfaces of its two valves, whose outlines range from semicircular to broadly rectangular.^[1]

Key facts

The species name costata refers to a shell with strong rib-like ridges. The feature in its name can be found in the actual shell’s markings.^[1]

Time and place

It is a fossil from the Furongian of the Late Cambrian. The research material came from the lower Guole Formation in the Jingxi region of present-day Guangxi, China. It provides evidence for studying ancient shelled animals of southern China.^[1]

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

Size, form and skeleton

The shell is weakly biconvex or has one flat valve. It is widest along the posterior hinge line, with finer lines between strong radial ridges.^[1]

Billingsella costata was a small brachiopod of shallow Late Cambrian seas. In a study of fossils from present-day Guangxi, China, twelve ventral valves averaged about 8mm long and about 1cm wide. Strong markings extended across a shell broader than it was long.^[2]

Habitat and reproduction

A 2010 study provisionally interpreted the assemblage containing this species as living on calcareous mud in shallow seas near the coast. Material from several brachiopods together conveys a view of that ancient seafloor.^[1]

Fossil discovery

Researchers compared several internal and external moulds showing the inner and outer forms of dorsal and ventral valves. They used NIGP149462 as the type specimen and described it as a new species in the 2010 study.^[1]

References

1. Zhan et al. (2010) — Late Cambrian brachiopods from Jingxi
2. Zhan et al. (2010) — Late Cambrian brachiopods from Jingxi, Guangxi
3. Study — Obolella shells from Greenland

Research questions

Some material previously grouped under another name was reconsidered in the new-species study. Detailed differences such as shell width and the strength and arrangement of ridges provided clues for distinguishing the species.^[1]

Observation

In the illustration, follow the strong ridges extending from the broad hinge line toward the front of the shell. Then examine the finer lines between them and the lines following the perimeter.^[1]