Shen Chenchen
Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas, United States of America.
Biodiversity Institute, University of Kansas, Dyche Hall,Lawrence, Kansas, United States of America.
PLoS One. 2025 May 7;20(5):e0320932. doi: 10.1371/journal.pone.0320932. eCollection 2025.
Kalops is a genus of early ray-finned fish in North America. It is distinguished from early actinopterygians by the combination of the following characters: subterminal mouth, rounded oval shaped lacrimal, multiple small supraorbitals and suborbitals. So far, it has been only excavated from the Serpukhovian (Late Mississippian) Bear Gulch Limestone in Montana. Here, a new species of this genus, Kalops loganensis n. sp., is described based on two specimens from the Moscovian Logan Quarry Shales in Indiana. The phylogenetic analysis indicates that the new species is a member of Kalops and recovered as the sister of the other two species, and the genus is recovered as a basal Actinopterygii, as the sister group of some other genera from the Bear Gulch Limestone. This new species is the first record of Kalops outside of Bear Gulch. It provides evidence of survivability of this genus, and as the youngest member, proves that Kalops lived at least through the Mid-Pennsylvanian in North America.
卡洛普斯鱼是北美洲一种早期的辐鳍鱼类。它与早期的辐鳍鱼类的区别在于具有以下特征组合:口位于端部下方、泪骨呈圆形椭圆形、有多个小的眶上骨和眶下骨。到目前为止,它仅在蒙大拿州的谢尔普霍夫阶(晚密西西比世)贝尔古尔奇石灰岩中被发掘出来。在此,基于来自印第安纳州莫斯科维阶洛根采石场页岩的两个标本,描述了该属的一个新物种——洛根卡洛普斯鱼(Kalops loganensis n. sp.)。系统发育分析表明,新物种是卡洛普斯鱼属的成员,被恢复为另外两个物种的姐妹种,并且该属被恢复为基干辐鳍鱼类,是贝尔古尔奇石灰岩中其他一些属的姐妹群。这个新物种是贝尔古尔奇以外卡洛普斯鱼属的首次记录。它提供了该属生存能力的证据,并且作为最年轻的成员,证明卡洛普斯鱼至少在北美洲一直生存到宾夕法尼亚纪中期。