Description

About Diplacanthus fossil

Diplacanthus crassisimus, an acanthodian species, is a small fish ranging from 10 mm to approximately 150 mm in size. What sets this fish apart are its notably long dorsal fin spines. While the spines on its pectoral, pelvic, prepelvic, and anal fins are smaller, they are still relatively large compared to those found on most other acanthodians.

This particular species of Diplacanthus lived around 385 million years ago during the Middle Devonian period in Scotland. At that time, Scotland was part of the Orcadian Basin, a vast complex of lakes that stretched for hundreds of miles. This period is often referred to as the “Age of Fishes” due to the dominance of fishes in almost every niche of lakes and seas. Diplacanthus crassisimus coexisted in these lakes with other species such as the acanthodian Mesacanthus, the osteolepids Gyroptychius, Osteolepis, and Thursius, the porolepid Glyptolepis, the lungfish Dipterus, the enigmatic Palaeospondylus gunni, and the placoderms Dickosteus, Coccosteus, Pterichtyodes, Rhamphodopsis, and Homostius.

The Acanthodii, or “spiny sharks,” are one of the earliest known groups of jawed vertebrates found in the fossil record. Their presence dates back to the Lower-Silurian period. However, they disappeared from the fossil record long after the Permian-Triassic extinction event, which had already caused a decline in their diversity.

Taxonomically, Diplacanthus crassisimus belongs to the Diplacanthidae, a subclass of Acanthodii. Although these fish also had a skin cover of denticles, it is uncertain whether they are closely related to sharks. Other Diplacanthidae species found in the Middle-Devonian of Scotland include Diplacanthus tenuistriatus and Rhadinacanthus longispinus.