Katian (Late Ordovician) trilobites of the North Qilian Mountains and their palaeogeographical implications for the Proto-Tethys Archipelagic Ocean (PTAO)

Trilobites from the middle Koumenzi Formation (Katian, Upper Ordovician) of the North Qilian Mountains, Menyuan, northeastern Qinghai Province are systematically documented for the first time. The fauna consists of five families, seven genera and seven species, amongst which one is new (Remopleurides zhangi sp. nov.), showing a close relationship to those of the Kazakh terranes (such as Chu-Ili terrane, Chingiz-Tarbagatai area and KNNTS (Karatau-Naryn and North-Tien Shan Microcontinents)), North China and Laurentia palaeoplates during the Katian (Late Ordovician). The cluster and Non-metric Multidimensional Scaling analyses of the Middle–Late Ordovician (late Darriwilian–Katian) trilobite faunas with 299 genera or subgenera from 46 horizons of 37 areas, provide valuable information for the palaeogeographical reconstruction of the Proto-Tethys Archipelagic Ocean (PTAO) of this interval. The Qilian terrane and adjacent areas are essential components of the PTAO, some of which include the ...