奥陶纪肿笔石类笔石的研究

A Study of Ordovician Genus Oncograptus

首次研究了采自江西玉山下奥陶统宁国组的一个半立体状保存的肿笔石标本(新种)Cardiograptus angustus Zone。研究表明,其发育型式为等称笔石式,始部最初几对胞管(th11除外)向外弯曲,与Cardiograptus angustus(Jin)特征一致。据此对Oncograptus属的属征作了重新厘定和种的归并。

A semi Spatial three-dimensional Oncograptus specimen(new species)is first studied,which was collected from the Cardiogratus angustus Zone of the Lower Ordovician Ningkuo Formation in Yushan,Jiangxi.The study indicates that its developing pattern is called isograptid,and several pairs of thecaes on the initial part curve is outwards(except th11).Their characteristics are consistent with Cardiogratus angustus(Jin).It is necessary to define the features of Oncograptus and its species in order to make an incorporation of the species.