LOUWOICHTHYIFORMES, Xu, 2021

Xu, Guang-Hui, 2021, A new stem-neopterygian fish from the Middle Triassic (Anisian) of Yunnan, China, with a reassessment of the relationships of early neopterygian clades, Zoological Journal of the Linnean Society 191, pp. 375-394 : 377

LOUWOICHTHYIFORMES ORD. NOV.

Diagnosis: Stem group of neopterygians distinguished from other members of this clade by the following combination of features (autapomorphies identified with an asterisk): single suborbital confined between dermosphenotic and preopercle or lost; maxilla relatively short and deep, ending at level of the posterior orbital margin; presence of teeth only on anterior half portions of both jaws; preopercle anteriorly inclined, contacting maxilla anteriorly (*); posttemporal relatively narrow, not reaching median line; branchiostegal rays relatively few, two or three pairs in number; five or more caudal fin rays in epaxial portion; subopercle slightly larger than opercle, with prominent anteroventral extension (*); and 1:1 ratio of distally segmented fin rays to endoskeletal radials in dorsal and anal fins.

Content: Louwoichthyidae and Pseudobeaconiidae López-Arbarello & Zavattieri, 2008 .

Type family: Louwoichthyidae .

Geographical distribution and age: Luoping and Luxi, Yunnan, China ; Monte San Giorgio area , Switzerland ; Perledo and Ca’ del Frate, Italy; Mendoza, Argentina ; Middle to Late Triassic.