湘西花垣中寒武统具表面装饰的管状微体化石

Ornamented Tubes from Middle Cambrian of Huayuan, West Hunan, China

对采自湘西花垣县排碧剖面中寒武统花桥组灰岩中具表面装饰的磷灰石质管状化石 (Or namentedtubes)进行了研究 ,依据化石的壳面装饰特征 ,建立了 3个形态类型 :OrnamentedTubeFormⅠ ,OrnamentedTubeFormⅡ和OrnamentedTubeFormⅢ。其中Ⅰ型壳体表面装饰有尖细的小刺 ,多数标本壳刺成行排列 ,行间存在宽约 0 0 1～ 0 0 5mm的间隔 ;Ⅱ型管体表面具有零散稀疏而不规则分布的斑疹状壳饰 ,壳体微微向外弯曲的一侧具有一列粗壮的呈锯齿状排列的脊刺 ;Ⅲ型整个壳体表面布满圆形、卵圆形瘤状壳饰 ,壳饰中空 ,与壳体内腔相通 ,壳体微微向外弯曲的一侧具有一列粗壮的呈羽状排列的脊刺。从壳体形态、表面装饰特征分析 ,这类管状化石可能是节肢动物(如高肌虫类 )生物体壳瓣上的前刺或背部的刺等管状硬体构造。

The problematic phosphatic tubular microfossils with ornamented sculptures documented herein were collected from limestones of the Middle Cambrian Huaqiao Formation in the Paibi section, Huayuan County, Hunan Province, China. Three morphological patterns, including Ornamented Tube Form Ⅰ,Ornamented Tube Form Ⅱ and Ornamented Tube Form Ⅲ are described, and their biological affinities are briefly discussed. Based on the features of ornamented sculptures of the fossils, the authors tentatively suggest that these ornamented tubes may represent carapace spines of some Cambrian bradoriid crustaceans.