Aerliceaster nexosus n. gen. n. sp. (Echinodermata), one of the oldest of known asteroids, is based on six specimens from the Floian (Early Ordovician) Garden City Formation of Idaho, and Kolataster perplexus n. gen. n. sp. is based on two specimens from the Sandian (Late Ordovician) Mifflin Formation of Illinois. Although the asterozoan skeleton is subdivided into few ossicular categories, evolutionary derivations of all the categories are not fully established, and therefore published evaluations differ. Beginning with phylogenetic work placing asteroid ancestry within the Somasteroidea together with the new taxa described herein, aspects of early asteroid morphology are evaluated and ambiguities in need of further study identified. Uncertainties are considered to be founded in rapid early asterozoan diversification and the scanty fossil record.UUID: http://zoobank.org/b43d07cc-c8fb-4a84-bc6f-40aa6e0daea2

中文翻译：

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两个新的早期小行星（棘皮动物纲）和早期小行星演化

铁线莲n. 将军 n. sp。（棘皮动物）是已知最古老的小行星之一，基于爱达荷州弗洛伊安（早奥陶世）花园城市组的六个标本，以及苦瓜n. 将军 n. sp。是基于来自伊利诺伊州三叠纪（晚奥陶世）米夫林组的两个标本。尽管星虫骨骼被细分为几个听骨类别，但所有类别的进化推导尚未完全确定，因此已发表的评估有所不同。从将小行星祖先与本文描述的新分类群一起置于 Somasteroidea 内的系统发育工作开始，评估了早期小行星形态的各个方面，并确定了需要进一步研究的模糊性。不确定性被认为是建立在快速的早期天体动物多样化和稀少的化石记录中。UUID：http://zoobank.org/b43d07cc-c8fb-4a84-bc6f-40aa6e0daea2