Palaeontology of decabrachiate Cephalopoda - an ultrastructural approach to their morphogeny and phylogeny

直到今天，无论是新的还是古生物学的方法都不能阐明十足类鞘总科的起源和系统发育。这一问题主要是由于化石记录相对较差所致。然而，最近在日本和加拿大的晚白垩世出现了新的(尚未研究的)关键分类群贝壳，如Naefia，Groenlandibelus和Conoteuthis。它们原始的(未改变的)贝壳提供了一种独特的可能性，以获得对仍不清楚的贝壳结构以及十臂角骨的神秘起源的新见解。因此，用扫描电子显微镜对Naefia、Groenlandibelus和Conoteuthis的贝壳超微结构进行研究，并将其与其他前新生代、新生代和现代十肢动物以及贝伦诺式鞘藻类进行比较，是本课题的目标。从而建立了一个令人信服的、适用的胚根壳结构模型。结果将被整合到由形态和分子数据组成的联合分支分析中。

Until today, neither neontological nor palaeontological approaches have been able to clarify the origin and the phylogeny of the decabrachiate Coleoidea. This problem is mainly due to a comparatively poor fossil record. However, new (not yet studied) shells of key taxa such as Naefia, Groenlandibelus, and Conoteuthis have recently appeared from the Late Cretaceous of Japan and Canada. Their original (unaltered) shells provide an unique possibility to get new insights into the still unclear shell construction as well as the enigmatic origin of the decabrachiate gladius. It is therefore the goal of the present project to study the shell ultrastructure of Naefia, Groenlandibelus, and Conoteuthis with SEM, to compare it with other pre-Cenozoic, Cenozoic, and Modern decabrachians, as well as with belemnoid coleoids. Thus, a convincing and applicable model of the coleoid shell construction shall be established. The results will be integrated in a combined cladistic analysis consisting of morphological and molecular data.