Minjinia

Minjinia turgenensis is a species of placoderm from the Devonian of Mongolia. It is known from a single specimen preserving part of the skull, including remains of endochondral bone, which indicates that a mineralised endoskeleton evolved before the split between bony and cartilaginous fish, and that it was lost in the latter group.[1]

Minjinia Temporal range: Pragian PreꞒ Ꞓ O S D C P T J K Pg N ↓
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	†Placodermi
Order:	†incertae sedis
Genus:	†Minjinia Brazeau et al., 2020
Species:	†M. turgenensis
Binomial name
†Minjinia turgenensis Brazeau et al., 2020

Classification

In the phylogenetic analysis ran by Brazeau et al., M. turgenensis was found as the sister taxon of a clade formed by Entelognathus, Ramirosuarezia, Janusiscus and the crown gnathostomes. A cladogram simplified from their analysis is shown below:[1]

	Galeaspida     Osteostraci   Gnathostomata   Antiarchi     Rhenanida       Petalichthyida       Ptyctodontida       Arthrodira       Minjinia       Entelognathus       Ramirosuarezia       Janusiscus     Eugnathostomata   Chondrichthyes     Osteichthyes

References

1. Brazeau, Martin D.; Giles, Sam; Dearden, Richard P.; Jerve, Anna; Ariunchimeg, Ya.; Zorig, E.; Sansom, Robert; Guillerme, Thomas; Castiello, Marco (7 September 2020). "Endochondral bone in an Early Devonian 'placoderm' from Mongolia". Nature Ecology & Evolution. doi:10.1038/s41559-020-01290-2. PMID 32895518.