Polygnathus communis gancaohuensis subsp. nov. (Conodonta) from the Tournaisian-Visean boundary beds of Xinjiang, NW China and the phylogeny of Polygnathus communis Branson et Mehl 1934. Acta Micropalaeontologica Sinica, 21(2), June 2004: 136-147. 144 [Zoological Record Volume 140]