Coccosteus

Unnamed genus (ANU V244, Young, Lelièvre and Goujet 2001; Hu, Lu and Young 2017; Early Devonian) nests with Cheiracanthus in the LRT. It is a phylogenetically miniaturized descendant of Coccosteus. Here the palatine (blue) has a carpet of teeth. The dentary is a slender strip.The maxilla is not yet developed.

Coccosteus cuspidatus (diagram specimen – Miller ex Agassiz 1841 Miller and Westoll 1968; Middle-Late Devonian) is a small, basal arthrodire that preserves post-crania. The lacrimal and postorbital are fused. The supratemporal and intertemporal are split. The nares are anterior as in ANU V244.

Coccosteus ROM 15381 1 specimen (Middle-Late Devonian) is a small, basal arthrodire that preserves post-crania. The ventral mandible is double convex. The frontal has a pineal opening. The quadrate does not curl anteriorly distinct from the diagram (above).

Coccosteus wteeth specimen (Middle-Late Devonian) has anterordorsal nares and a premaxillary tooth plate. An antorbital fenestra separates the orbit from the rostrum tip as in catfish. The long narrow pectoral fin is preserved against the lateral carapace.

Agassiz JLR 1844. Monographie de poissons fossiles des Vieux Grès Rouges ou Système Dévonien (Old Red Sandstone) des Îles Britanniques et de Russie. Imprimerie de Petitpierre et Prince, Neuchâtel.

Eichwald K 1840. Die Thier- und Pflanzenreste des alten rothen Sandsteins und Bergkalks im Novogrodschen Gouvernement. Bulletin Scientifique publie par l’Academie Imperiale des Sciences de Saint-Petersbourg et redige par son Secretaire perpetuel 7(6, 7):78–91.

Hu Y, Lu J and Young 2017. New findings in a 400 million-year-old Devonian placoderm shed light on jaw structure and function in basal gnathostomes. Nature Scientific Reports 7: 7813 DOI:10.1038/s41598-017-07674-y

Miles RS and Westoll TS 1968. The placoderm fish Coccosteus cuspidatus Miller ex Agassiz from the Middle Old Red Sandstone of Scotland. Part 1. Transactions of the Royal Society of Edinburgh 67:373–476.

Young G C, Lelièvre H and Goujet D 2001. Primitive jaw structure in an articulated brachythoracid arthrodire (placoderm fish; Early Devonian) from southeastern Australia. J. Vertebr. Paleontol. 21, 670–678.

wiki/Coccosteus

Placodermi

Drepanaspis

Qilinyu

Manta