广西六景节甲鱼化石

<正> 1973年夏,笔者在横县六景镇北釆获若干节甲鱼化石碎片,其中两件保存不全的刺体,曾以系统位置未定的窄鳞鱼类(又称北极鱼)报道过(刘时藩,1980)。1980年5月,笔者又在原来采集化石的地点和同一层位的另一地点,又采获了数十件鱼化石甲片。化石产于那高岭组的底部的黄绿色、灰色的泥岩和泥灰岩中。经初步观察,这些分离保存不全的甲片,几乎全属于节甲类,其中大多数还应隶属辐纹鱼科(Actinolepidae)。本文先将其可确认者作初步报道,同时对这些鱼化石的系统位置以及有关的地质问题也作初步讨论。

PRELIMINARY NOTE ON THE ARTHRODIRA FROM GUANGXI,CHINA

Some isolated plates of Arthrodira described here were found from Lower Devonian system of Lujing, Guangxi Province, China. They conclude four spinal bodies belonging to Asiacanthus multituberculatus; three median dorsal plates and an anterior ventro-lateral plate referred to Actinolepidae indet, as well as other four indeterminate spinal bodies. Denison E. (1978)suggested that the Asiacanthus had been originally referred to acanthodians, but the ornament shows more similarity to that of the spinal plates of some Placodermi. The feature displaied by the new specimens also suggests that the Asiacanthus should be referred undoubtedly to Arthrodira because the lateral borders of spinal bordy attach to the anterior lateral plate and anterior ventro-lateral plate respectively in a simple harmonic suture, while anterior lateral plate and the anterior ventrolateral plate do not occur in acanthodians. There are a lot of Arthrodira fossils in the base of Nakaoling Formation, most of which belong to Actinolepidae. These fossils mainly appear in Siegenian in Europe and North America. The circumstance seems o show that the Nakaoling Formation is of Siegenian.