Jinjuichthys

Jinjuichthys is an extinct genus of ray-finned fish, possibly an ichthyodectiform, from the Early Cretaceous of South Korea.

Discovery and naming

The generic name Jinjuichthys means 'fish of Jinju' based on the city with the same name to which its type locality Jinju Formation belongs, while the specific name cheongi references the Korean geologist Cheong Chang Hi in honor of his contributions to the understanding of the biogeography of Korea. The holotype is a relatively complete skeleton that lacks the caudal region, with an estimated standard length of, while the paratype consists of the caudal skeleton and caudal fin.

Classification

Jinjuichthys is included within the family Chuhsiungichthyidae which has been traditionally placed within the order Ichthyodectiformes. However, Alvarado-Ortega questioned the placement of Bardackichthys and members of Chuhsiungichthyidae within ichthyodectiforms based on phylogenetic analysis and various anatomical differences. The uroneural of Jinjuichthys is preserved in dorsal position, unlike that of ichthyodectiforms which is preserved in lateral position. Jinjuichthys also differed from other ichthyodectiforms by having three or four longitudinal cavities instead of two, lacking the saber-like rays in the pelvic and pectoral fin, and possibly lacking the ethmopalatine, a cranial suture connecting the ethmoid and palatine bone.