Mesacanthus ('middle spine') is an extinct genus of acanthodian fish from Devonian Scotland. It is among the more primitive of the Devonian acanthodians.
Mesacanthus ('middle spine') is an extinct genus of acanthodian fish from Devonian Scotland. It is among the more primitive of the Devonian acanthodians.
==Description== thumb|250px|Mesacanthus peachi fossil from the Sandwick Fish Beds of [[Quoyloo, Scotland.]] Mesacanthus body fossils have pectoral, pelvic, anal and dorsal fin spines, as well as a pair of prepelvic spines, which are intermediate between the pectoral and pelvic fin spines. They also have small, unornamented, diamond shaped scales. According to Agassiz, the genus also has a distinct tail in which the upper lobe extends to a sharp point and the lower lobe forms a small triangle. Overall the genus is small (average length = 30mm) and fairly conservative, anatomically speaking, for acanthodians.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).