中国湘南早侏罗世双壳类壳体内的遗迹化石——兼论遗迹化石属Talpina Hagenow,1840(英文)

AN EARLY JURASSIC TALPINA -DOMINATED ASSEMBLAGE OF BORINGS IN BIVALVE SHELLS FROM SOUTHERN HUNAN, CHINA, WITH REMARKS ON THE ICHNOGENUS TALPINA HAGENOW, 1840

论文描述的双壳类壳体内的钻孔遗迹组合发现于湖南省东南部宜章县下坪附近的心田门组上部(早侏罗世,早辛涅缪尔期)浅海沉积地层中。这个遗迹化石群中,帚虫类动物制造的钻孔Talpinahunanensisichnosp.nov.(新遗迹化石种)明显地占据了大部分,偶尔共生的其它钻孔包括:Rogerellaichnosp.(蔓足亚纲尖胸类的遗迹)、Calcideletrixichnosp.(可能是藻类的遗迹)、藻或菌造的遗迹(暂定为"Mycelites"ichnosp.)、以及一种可能被海绵动物制造的未定钻孔。生物侵蚀者侵害了海底上较大的双壳类壳体。钻孔保存为天然印模(石核),它们是文石质壳体溶解后留下的空间中的充填物。此外,文中还讨论了遗迹化石属TalpinaHagenow,1840,尤其讨论了有关遗迹种颇为复杂的鉴别问题,同时校正了该遗迹属的属征。

An assemblage of borings in bivalve shells is described from shallow-marine deposits of the upper Xintianmen Formation (Early Jurassic, early Sinemurian) near Xiaping, Yizhang County, south-eastern Hunan Province, southern China. Talpina hunanensis ichnosp. nov., a new ichnospecies of borings constructed by Phoronida, clearly dominates this ichnocoenosis. Other borings occasionally co-occurring with T. hunanensis comprise Rogerella ichnosp. (produced by acrothoracican Cirripedia), Calcideletrix ichnosp. (probably bored by algae), microborings of algae or fungi which may preliminarily be assigned to ' Mycelites ' ichnosp., and an unidentified type of boring possibly caused by sponges. The bioeroders infested larger bivalve shells that were exposed on the seafloor. The borings are preserved as natural casts (Steinkerns) in the voids left after dissolution of the aragonitic host shells. In addition, the ichnogenus Talpina Hagenow, 1840 is discussed, especially with regard to the often difficult differentiation of ichnospecies, and its diagnosis is emended.