Taxonomic revision of Asialepidotus shingyiensis Su, 1959 (Halecomorphi, Holostei) from the Middle Triassic (Ladinian) of Guizhou and Yunnan, China

Abstract

The holostean fish Asialepidotus shingyiensis, from the Middle Triassic (Ladinian) of Guizhou and Yunnan, China, was previously regarded as either a semionotiform ginglymodian or an amiiform halecomorph. This study provides a revision of this taxonomically controversial taxon based on a comparative study including the holotype and 50 new specimens. Newly recognized anatomical information includes the dermal component on the sphenotic, complete series of circumorbital bones, palatal bones, quadratojugal, hyomandibula, sensory canal in the maxilla, notched posterior margin of the maxilla, median gular, and many elements on the medial surface of the lower jaw. Results of a cladistic analysis incorporating these new data place Asialepidotus as an ionoscopiform halecomorph that is more derived than Subortichthys and Panxianichthys, and consists of the sister taxon of Robustichthys and all other ionoscopiforms.

Keywords

• triassic
• ionoscopiformes
• osteology
• phylogeny
• south china