A new ichthyodectiform (Pisces, Teleostei) from the Lower Cretaceous of South Korea and its paleobiogeographic implication

摘要: Here we report the first ichthyodectiform in Jinju Biota from Lower Cretaceous Formation, Shindong Group, at Hyojagyo, City, South Korea. It shows following characters: 1) jaw teeth single series; 2) coracoid expanded ventrally; 3) dorsal fin situated posteriorly, with its origin opposite to that of long anal fin. Besides, caudal skeleton also exhibits certain features often seen basal ichthyodectiforms and some other primitive teleosts. The fish is noticeably similar species referred Chuhsiungichthys upper Dobaru Kumagai formations Wakino Subgroup Kanmon Group Kyushu, Japan, tsanglingensis Jiangdihe Formation age Chuxiong, Yunnah Province, China. was, turn, comparable Mesoclupea showchangensis Shouchang Linhai, Guantou Zhuji, Zhejiang latter two genera show characters mentioned above. Nevertheless, Korea, those Japan China, can easily be distinguished their higher body depth shorter length; proportionally longer head; fins; lower number vertebrae, abdominal less than caudal; vertebrae deeper long. Among them distinct even body, presence urodermal. In addition, different having a much but more ridges grooves on lateral face vertebrae. Thus, cannot either or Mesoclupea, establishing new genus for it warranted. Asian ichthyodectiforms, Chuhsiungichthys, Jinjuichthys, may most probably form monophyletic group Chuhsiungichthyidae, known so far restricted fresh and/or brackish waters East Asia. materials Korea are better preserved thereby allowing relatively complete description fish, providing information discussion phylogenetic position, enriching diversity local fauna, helping us understand paleobiogeographical distribution geological background. (C) 2013 Elsevier Ltd. All rights reserved.