|Title||A new primitive acanthomorph fish from the Greenhorn Formation (Late Cretaceous) of Nebraska|
|Publication Type||Journal Article|
|Year of Publication||1998|
|Authors||Arratia GF, Chorn J|
|Journal||Journal of Vertebrate Paleontology|
|Keywords||Anatomy and Histology - Gross anatomy 62800, Animal distribution - 63000, Chordata: general and systematic - Pisces 00504, General biology - Taxonomy, Geological periods - Cretaceous, nomenclature and terminology 11102, Osteichthyes  Paleobiology Systematics and Taxonomy Pisces Vertebrata Chordata Animalia 62510, Paleozoology - 64722|
A new acanthomorph genus is described from the Greenhorn Formation (Turonian) of north eastern Nebraska. The type and only specimen of this genus is a nearly complete skull and postcranial skeleton characterized by an interesting combination of features such as a prominent, anteriorly thickened supraoccipital crest, protrusile upper jaw with well developed premaxilla, opercular bones without spines, 39 vertebral centra, pectorals very low on the flank, pelvic fins in abdominal position, medial pelvic process distally ossified, true dorsal fin-spines present, and spinoid scales covering the trunk. The Late Cretaceous acanthomorph dagAipichthys shares a few characters with the new genus including deeply cleft caudal fin and nine principal caudal rays on the upper lobe of the caudal fin. Characters are shared also with dagAraripichthys from the Early Cretaceous of Brazil. The material described resembles in certain characters (e.g., supraneurals, abdominal vertebrae and probably paired fin placement) the acanthomorph dagFerrifrons rugosus, represented by a single incomplete specimen from the Niobrara Chalk (Santonian). Based on a few synapomorphies, the new genus and dagFerrifrons are included in the new fossil family Ferrifronsidae.