Lower Permian reef-dwelling brachiopod faunas from the Tarim Basin, Northwest China: biostratigraphy, palaeoecology and biogeography

This paper describes 68 brachiopod species (eight undeterminate species) in 59 genera from the Uzunbulak reef complex of the Asselian to early Artinskian at the northern Tarim Basin, northwestern China. One new tribe, Tarimelliini, and one new genus( Tarimella)and 15 new species are created. The reef-dwelling brachiopods are grouped into five associations based on their various ecological niches in the reef complex, and each appears unique ecological preference. Four assemblages, Cartorhium rhomboidalis-Purdonella nikitini, Eliva lyra-Rhynchopora zaljakensis, Chaoiella? tenuireticulatus-Stereochia ruani and Tarimella tarimensis-Cimmeriella decemplecta Assemblages, are established on the basis of the stratigraphical distributions of brachiopod species. The brachiopod faunal correlations show that the Tarim Basin was biogeographically strongly influenced by biota of the Ural-Timan seaway and had no connection with Cathaysian Tethyuan (South China and North China) faunas during the Asselian-Sakmarian. In the early Artinskian the Tarim faunas appear closer affinity with those of the eastern Tethys than those of the Urals-Timan region. The close relation with eastern Tethyan faunas is also reinforced by many holdovers of the Tarim faunas that occurred in the Middle Permian reefal complex (or bioherm) of South China and southern Thailand.