Data from: Evolutionary implications of a new transitional blastozoan echinoderm from the mid Cambrian of Czech Republic

The primitive blastozoan Felbabkacystis luckae n. gen. n. sp. is described from the Drumian Jince Formation, Barrandian area (Czech Republic) based on eleven fairly well-preserved specimens. Its unique body plan organization is composed of a relatively long stalk-like imbricate structure directly connected to the aboral imbricate cup of the test and of an adoral vaulted tessellate test supporting the ambulacral and brachiolar systems. Its bipartite test, called prototheca, highlights the evolution of the body wall among blastozoans. Felbabkacystis n. gen. shows the combination of plesiomorphic (imbricate stalk-like appendage) and derived features (highly domed peristome, elongate epispires). The new genus is interpreted as a transitional form between calyx-bearing and theca-bearing blastozoans, and is attributed to the new Family Felbabkacystidae. The lithology, the associated fauna and the possession of a long stalk suggest that Felbabkacystis was probably a low-level suspension feeder in relatively deep settings.本研究基于11件保存较为完好的标本，对产自捷克巴拉德地区德鲁姆阶延采组（Jince Formation）的原始芽囊动物（blastozoan）新属新种Felbabkacystis luckae（n. gen. n. sp.）进行了系统描述。该类群独特的躯体构型由直接连接壳体（test）反口端覆瓦状杯的相对修长的茎状覆瓦结构，以及支撑步带与腕纤毛系统的口端穹窿状镶嵌壳体共同构成。其被称为原鞘（prototheca）的二分壳体，为阐明芽囊动物类群的体壁演化提供了关键依据。新属Felbabkacystis兼具祖征（覆瓦状茎状附肢）与衍征（高度穹窿的口围（peristome）、细长的围鳃孔（epispires））。该新属被认为是具萼芽囊动物与具鞘芽囊动物之间的过渡类群，隶属于新建立的费尔巴库克囊科（Felbabkacystidae）。结合岩性特征、伴生动物群以及该类群具有长茎的形态特征，可推断Felbabkacystis大概率为栖息于相对较深水环境的底栖悬浮摄食者。