Gyracanthides

Gyracanthides is an extinct genus of acanthodian gnathostome, known from Devonian to Early Carboniferous.

Description
Gyracanthides is large acanthodian, G. murrayi reached the length up to 1.2 m. The pectoral fin spines are large compared to its body, for specimen that have estimated to be 90 cm had pectoral fin spines around 40 cm long. A recent study suggested that Gyracanthides is closely related to chondrichthyans (as currently delimited), and that acanthodians are paraphyletic.