Aulocopium aurantium

Overview

Aulocopium is an Ordovician sponge. Species descriptions include forms ranging from cylindrical to inverted cones narrowing downward. Even within one species, fossil outlines can be preserved in several ways.^[1]

Key facts

Concentrically repeating wrinkles are described on the lower surface. These should be examined alongside an outline broad above and narrowing below. Alternating between the overall outline and small wrinkles reveals different aspects of a sponge fossil.^[1]

Time and place

It is known through Ordovician specimens and literature. The Ordovician was roughly 490–440 million years ago. A 2001 species-specific study compared material of several forms together.^[1][2]

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

Size, form and skeleton

One described form shows a short cylindrical upper portion and a tapering lower region. The lower outer layer bears concentric wrinkles, and the upper opening is recorded as relatively narrow. This form can be examined alongside other outlines of the same species.^[1]

The Ordovician sponge Aulocopium aurantium reaches 22cm in diameter and shows column-like or inverted-conical forms. Concentric wrinkles remain below, providing conspicuous clues even in fossils without the whole body preserved.^[3]

Habitat and reproduction

Understanding a sponge body involves research on internal structures as well as the exterior. In Aulocopium fossils, parts of the inner wall may be missing, or the density of preserved material may vary between regions. This research explores the original body through solidly preserved material.^[1]

Fossil discovery

A 2001 study addressed species-specific features and variation in the form of Aulocopium aurantium. Description continued through comparisons of distinct material such as collection specimen P5. Beyond knowing a name, we can examine which fossil is being described.^[1]

References

1. Rhebergen et al. (2001) — Diverse fossil forms of Aulocopium
2. International Commission on Stratigraphy (2024) — Geological time chart
3. Aulocopium aurantium, Grondboor & Hamer 55 (2001)
4. The Burgess Shale: Choia carteri

Research questions

Did depressions in the fossil have the same shape in life? Silicification and erosion affect how external and internal regions are preserved. This is an intriguing case requiring biological form and fossilization history to be read together.^[1]

Observation

Follow the outline from the broad upper portion downward as it narrows. Examining basal concentric wrinkles separately from the upper opening reveals several features within the same fossil.^[1]