Radiolites sauvagesi

Overview

Picture a bivalve with a column-like shell. Radiolites sauvagesi is a Cretaceous bivalve described as having a cylindrical shell with a circular cross-section. Moving beyond the familiar image of two flat shells reveals diverse body forms.^[2]

Key facts

Museum specimen numbers provide clues for finding old papers. J09093 at the National Museum of Natural History in Paris is registered as both a complete specimen and illustrated material. The catalog also links it to Toucas’s 1908 study and the location of its figure.^[1]

Time and place

Museum specimen J09093 is Late Cretaceous Coniacian material from Gatigues in present-day Gard, France. The Cretaceous spanned approximately 140–66 million years ago. Locating this specimen in time and place helps us picture the strata preserving the column-shaped bivalve.^[1][3]

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

Size, form and skeleton

Striking features in the species description are an elongated cylindrical outline and a round cross-section. Considering height and transverse section separately offers different ways to read the same shell.^[2]

Radiolites sauvagesi was an unusual bivalve of Cretaceous seas. A fossil studied at Djebel Metrassi in present-day Algeria is described as having a cylindrical shell 5 cm tall and 3.5 cm in diameter. Unlike a familiar flat bivalve, its shell rises like a small barrel.^[4]

Habitat and reproduction

This bivalve had a soft body inside a two-valved shell. Its column-like shell illustrates diversity in bivalve form. Comparing the height of the valves and where they meet helps reveal how the body was arranged inside.^[2]

Fossil discovery

A specimen illustrated in a 1908 study connects with a modern museum catalog. Matching an old figure number to a collection number allows a particular fossil, difficult to find by name alone, to be traced again. The old description and current collection continue the same research story.^[1]

References

1. National Museum of Natural History, Paris — Radiolites specimen J09093
2. 2018 study — The shell of Radiolites sauvagesi
3. International Commission on Stratigraphy (2024) — Geological time chart
4. Aouissi·Salmi-Laouar·Ferré (2018) — Cretaceous invertebrates from Djebel Metrassi, Algeria
5. Weller — Description of the two valves of Ostrea congesta
6. Cretaceous Atlas of Ancient Life — Ostrea congesta

Research questions

What does a circular cross-section mean for the actual outline? Consider the column seen from the side separately from a section cut across it from above. A short descriptive term can be the key to understanding a three-dimensional body.^[2]

Observation

First look along the direction in which the shell elongates, then move your gaze to the low valve covering its top. Comparing its outline with a familiar flat bivalve reveals the distinctive arrangement of Radiolites.^[2]