Earliest silurian graptolites from kalpin, western Tarim, Xinjiang, China

Abstract

A graptolite fauna containing 13 species in seven genera is described from the basal part of the Middle Member of the Kalpintag Formation, in the Kalpin region of Xinjiang Province, northwestern China. The taxa are Avitograptus sp. aff. A. avitus (Davies), Hirsutograptus jideliensis (Koren’ & Mikhailova), Korenograptus laciniosus (Churkin & Carter), K.jerini (Koren’ & Melchin), K. aff. K. magnus (Churkin & Carter), Metabolograptus wangjiawanensis (Mu & Lin), M. parvulus (Lapworth), Normalograptus ajjeri (Legrand), N. angustus (Perner), N. mirnyensis (Obut & Sobolevskaya), Paramplexograptus madernii (Koren’ & Mikhailova), Par.? sp., and Persculptograptus sp. Approximately half of the species described have not been previously recorded from the Kalpin region. An early Silurian (Rhuddanian) age is indicated by H. jideliensis and K. jerini. The graptolite fauna recovered from the four sections in the Kalpin region shares numerous common species with faunas from the Yangtze region of China and from southern Kazakhstan.