凯里生物群中始海百合类形态功能、生态及埋藏特征初探

贵州剑河八郎中寒武世凯里生物群中始海百合十分丰富，化石标本多达1万多件，分属长茎型的卢氏中国始海百合（Sinoeocrinus Zhao, Huang et Gong,1994）及短茎型的球形中国始海百合（Sinoeocrinus globus Zhao et al, 1999）。它们均具有腕枝、萼、茎及吸盘，少数标本见有肛锥。幼年体缝孔不发育，成年体具有较发育的缝孔。大部分个体为单体生活。短茎型的萼呈球形，茎短，吸盘大，常固着在腕足动物外壳及三叶虫背壳碎片上。长茎的萼呈长椭圆球形茎长，吸盘小，常固着在砂泥质海底。两个种的腕肢也有差别，长茎的直长，短茎的旋转生长，显示两个种的形态差别及多样性。由于始海百合死亡后迅速被掩埋，80%以上的个体保存完整。化石大部分保存无定向性，显示静水环境，海底紊流很少，不仅显示原地埋藏特征，也为凯里生物群是原地埋藏提供了重要证据。

A Preliminary Study of Functional Morphology, Paleoecology and Taphonomy of Eocriniods from the Cambrian, Kaili Biota, Guizhou

Eocrinoids are very abundant in the Middle Cambrian Kaili Biota at Balang village, Jianhe County, Guizhou Province. Two species are present: the long stalked Sinoeocrinus lui Zhao, Huang et Gong, 1994 and the short stalked Sinoeocrinus globus Zhao et al., 1999. Over 10000 well preserved specimens have been collected including complete ontogenetic series for the two species. These specimens all show brachioles, thecae, stalks and attached discs, and a few specimens show anal pyramids. The development of surtural pores on the thecae appears as an obvious change during different growth stages. The surtural pores are not developed in juvenile stages, but are well-developed in adult individuals of both species. Most eocrinoids exhibit a solitary lifestyle. The theca of short stalked eocrinoids is spheroidal, with a large attached disc, often found attached to fragments of brachiopod shell, or to cranidia, or to thoracic segments of trilobites. The long stalked form possesses a small attached disc, which is often attached directly to the silty mudstone substrate. The brachioles of both species are also distinguished by two different growth modes, in which the long stalked forms grew straight up and the short-stalked forms grew spiral up. These characteristics are important in understanding the diversity, ontogeny and ecology of eocrinoids assemblages from the Kaili biota.