湘西北志留纪胴甲鱼化石

本文记述了采自湘西北澧县石门水库附近秀山组上段隶属云南鱼目的 Shimenolepis graniferus gen. et sp. nov. 和 QuJinolepidae gen. et sp. indet. 化石,对含鱼层的时代也进行了讨论.

THE ANTIARCHI FROM EARLY SILURIAN OF HUNAN

A few specimens of Antiarchi, named as Shimenolepis graniferus gen. et sp. nov., a new form of Yunnanolepiformes, and Qujinolepidae gen. et sp.. indet., are described from Early Silurian, the upper part of Xiushan Formation, near the Shimen Reservoir, Lixian county, Hunan Province. The Shimenolepis graniferus gen. et sp. nov. differs from Yunnanolepis chii, Y. parvus, Phymolepis, Qujinolepis and Liuliangolepis in possessing a short posterior ventrolateral plate. It is very similar to Zhanjilepis in the form of posterior ventrolateral plate, but differs from the Zhanjilepis in possessing tiny tubercles on the surface of the dermal bone, and the proportion of the length/breadth of the lateral lamina of the posterior ventrolateral plate. An anterior median dorsal plate very similar to that of Qujinolepis gracilis in form is referred to the Qujinolepidae. It differs from Qujinolepis gracilis in two points: the anterior ventral process situated near to the anterior margin, and the very long ventral median ridge exceeding the middle line of this plate. Because there is only one specimen available, it is reported as an indetermined genus and speci?s in this paper. They are the earlist Antiarchi discovered and first discribed in China as well as in the world, and are very important for inquiry into the origin of the Antiarchi and the relationship between the Antiarchi and Arthrodire.