Phylogenetic study of the cephalopoda based on anatomical, embryological and molecular data

1)比较胚胎学研究Tanabe和Shigeta在世界各地保存完好的材料的基础上，利用扫描电子显微镜研究了各种菊石的胚胎壳特征，并将结果与其他现存和化石头足类动物的数据进行了比较。结果表明，菊石类的胚胎壳特征与鹦鹉螺类大不相同，而与胶体类很相似。Tanabe现在和鸟场水族馆的kimio Uchiyama先生一起研究水族馆中活鹦鹉螺的胚胎壳发育。这些研究的细节将在1996年出版的《类氨古生物学》一书的一章中发表。比较解剖学研究：tanabe和Mapes（1995）描述了俄克拉何马石炭纪类氨克拉文角龙的颌部和齿颚，并讨论了其系统发育意义。(3)系统发育研究为了确定ammono总科在头足纲中的系统发育地位，Tanabe和Landman（美国自然历史博物馆，纽约）对5个操作分类单位的14个胚胎和解剖特征进行了分支学分析。因此，人们认识到头足纲由两个单系类群组成，即鹦鹉纲和新头足纲，后者包括球形目、ammono总目和coleo总目。这一结果将于1996年发表在《科学》杂志上分子生物学研究远藤正对著名的活化石鹦鹉螺进行分子系统研究。他也在分析保存在头足类动物硬组织中的生物分子，以获得分子进化的数据。

1) Comparative embryological studyOn the basis of well-preserved material from various localities throughout the world, Tanabe and Shigeta have investigated the embryonic shell features of the embryonic shells of various ammonoids using a scanning electron microsope, and the results were compared with data on other extant and fossil cephalopods. As a results, it was revealed that the embryonic shell features in ammonoids are quite different from those of nautilids but are quite similar to those of coleoids. Tanabe is now studying with Mr.Kimio Uchiyama of the Toba Aquarium on the embryonic shell development of living Nautilus in aquaria. Details of these studies will be published in a book chapter of "ammonoid Paleobiology" (Plenum Press) in 1996.2) Comparative anatomical studyTanabe and Mapes (1995) described the jaws and radula of a Carboniferous ammonoid Cravenoceras from Oklahoma and discussed its phylogenetic implications.3) Phylogenetic sutdyIn order to realize the phylogenetic position of the Ammonoidea within the Cephalopoda, Tanabe and Landman (American Museum of Natural History, New York) did a cladistic analysis of 14 embryonic and anatomical characters in five operational taxonomic units. As a result, it was realized the Cephalopoda consists of two monophyletic groups, the Nautiloidea and the Neocephalopoda, the latter includes the Sphaerorthocerida, Ammonoidea, and Coleoidea. This result will be published in Novitates in 1996.4) Molecular biological studyEndo is now doing research on the molecular systematic study on Nautilus, a well-known living fossil. He also is analyzing biomolecules preserved in cephalopod hard tissues to obtain data on molecular evolution.