Buchanosteus(节甲鱼类)的新材料及其生物地层学意义

记述了采自广西永福附近泥盆系的一鱼类化石标本。根据头甲轮廓和内颅特征，将其归入节甲鱼类。头甲的宽度大于后松果区长度，中颈片为梯形，后边缘片有较长的后突。内颅吻囊与筛后一枕区分开，耳区短；前眶后突不明显，位置靠后；后眶后突明显，远端不分叉。因此新材料应归入巴坎鱼属（Buchanosteus）。但眼孔大并朝向背侧上方，骨片上粒状突起纹饰的冠部和基部没有星状嵴等特征与Buchanosteus confertituberculatus（Chapman）不同，所以新材料应代表一新种，即Buchanosteus兴guangxiensis sp．nov．。还对澳大利亚与中国华南地区当时的古地理关系进行了讨论。

New material of Buchanosteus and its biostratigraphic significance

This paper describes a fossil fish specimen collected from the Lower Devonian near Yongfu,Guangxi. According to the outline of the head roof and features of endocranium,it is ascribed to Arthrodira. The width of the head roof is greater than the length of the post- pineal unit. The endocranium is divided into two parts,an ethemoidal region and a postethmo- occipital region. There are four lateral endocranium processes,namely,antorbital,supraorbital,anterior and posterior postor- bital processes,which are in keeping with those of Buchanosteus. So the new material ought to be ascribed to Buchanosteus. But the larger and dorso- laterally facing orbits, fine tubercular ornaments without fine radiating ridges on its cap and root are distinct from the features of B. confertituberculatus (Chapman). Thus the new material represents a new species of Buchanos- teus,that is B. guangxiensis sp. nov. The paper also discusses the paleogeographic relation between South China and Australia.