The Bivalve Yangtzedonta is not the Brachiopod Xianfengella
The alleged "holotype" of the bivalve Yangtzedontaprimitiva Yu, 1985 figured by Qian (2001) is a broken and distorted specimen of the brachiopod Xianfengella prima He and Yang, 1982 and not the holotype of Y. primitiva. Qian contends that the oldest recognized monoplacophoran, Maikhanella pristinis (Jiang, 1980), is neither a monoplacophoran nor the oldest molluscan fossil in the Meishucunian Stage of China. Furthermore, he considers that the oldest bivalve Xianfengoconcha elliptica Zhang, 1980 is an inarticulate brachiopod, not a mollusc. Watsonella yunnanensis (He and Yang, 1982), is associated with Yangtzedonta primitiva Yu but indicates no evolutionary relationship between the Classes Rostroconchia and Bivalvia in the Lower Cambrian Zhongyicun Member of the Yuhucun Formation. Qian's confusion in using non-molluscan fossils to discuss the early evolution of shelled molluscs also confuses the basic concepts of the respective groups.
作 者: YU Wen 作者单位: Department of Earth and Planetary Sciences,Western Australian Museum, Francis Street, Perth, Western Australia 6000, Australia 刊 名: 地质学报(英文版) SCI 英文刊名: ACTA GEOLOGICA SINICA 年,卷(期): 2005 79(6) 分类号: P5 关键词: Yangtzedonta Bivalvia Xianfengella Xianfengoconcha inarticulate brachiopods Yangtze micromolluscan fauna