Pentamerus oblongus

Pentamerus oblongus was a large-shelled brachiopod, or lamp shell, that dominated early Silurian marine communities. Brachiopods are marine invertebrates with two shells, resembling Roman oil lamps.12

Pentamerus oblongus communities thrived in waters about 30 to 60 meters deep, where sunlight was present but wave action was not too vigorous. These communities often included 5 to 20 other species. The genus Pentamerus is characterized by its rostrate, oval to pentagonal shell, with internal ridges and a spondylium in each valve. Brachiopods first appeared in the Cambrian Period and, though less numerous today, were once abundant.132