Gigantoproductus giganteus

Overview

Gigantoproductus giganteus is a large brachiopod of Carboniferous seas. Its two fitted shell valves evoke a clam. But the upper-and-lower relationship of the valves and the body’s symmetry reveal an animal different from a bivalve.^[1][2]

Key facts

One valve is thick and convex, while the opposite valve is thin and concave. This is a different combination from a familiar bivalve with two convex halves. Looking at the outside and inside of the large shell together is intriguing.^[1][2]

Time and place

It lived in seas of the late Mississippian in the Carboniferous, around 330 million years ago. Specimens from the western Daba Mountains in present-day central China were studied. Fossils preserved with other brachiopods reveal the marine fauna of the time.^[1][3]

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

Size, form and skeleton

The shell is broad near the hinge, with folds continuing toward the front. Specimens addressed in a 2012 study averaged about 10.5×7.6cm. The convex ventral valve and concave dorsal valve can be compared side by side.^[1][2]

Habitat and reproduction

Brachiopods are a marine group that filters small food particles from water. Water passes between the two valves, and an internal feeding organ functions within. Hard shells allow exploration of the world of small animals living on the seafloor.^[4]

Fossil discovery

In 2012, Qiao and Shen reviewed brachiopod fossils from the western Daba Mountains. They recorded sizes and forms by comparing several specimens of the same species with other species. The study examined an ancient marine assemblage together with its strata.^[1]

References

1. Late Mississippian (Early Carboniferous) brachiopods from the western Daba Mountains, central China
2. Treatise on Invertebrate Paleontology — Gigantoproductus
3. International Commission on Stratigraphy — Geological timescale
4. British Geological Survey — The body and feeding of brachiopods
5. Qiao & Shen2012 — Late Mississippian brachiopods of the Daba Mountains
6. International Commission on Stratigraphy — Geological timescale
7. Treatise on Invertebrate Paleontology — Gigantoproductus
8. Paleobiology Database — Fossil occurrence records for Pentremites
9. College of Wooster — Pentremites godoni from the Carboniferous of Illinois
10. Bauer — Fossil Focus: Blastoids

Research questions

How was the space between the valves used in life? Internal shell traces provide evidence for comparisons of feeding organs and muscles. Research examining internal structures as well as large external forms is important.^[2][4]

Observation

Imagine a convex valve fitting against a concave valve. Moving your gaze from the broad hinge to the anterior folds reveals the body’s symmetry and outline.^[1][2]