EVOLUTIONARY STUDY OF MARINE RELIC INVERTEBRATES

(1)生态学和分类学研究：Kase、Hayami、Hanai、Tabuki和Mori在西太平洋热带和亚热带海底洞穴中发现了一种奇特的原始无脊椎动物群。他们收集了许多活的和死的动物样本，分析了它们的生态和分类特征，为未来的进化研究奠定了基础。(2)发育生物学研究：Tanabe在鸟羽水族馆的k.u uchiyama先生的帮助下，研究了原始外耳蜗类头足类鹦鹉螺的胚胎壳发育模式，并在早期发现了圆盘状的无瓣有机壳（瘢痕）。在现存的单placophora中也发现了类似的圆盘状或低帽状初级壳，这表明它们的系统发育关系。(3)分子系统学研究：Endo， Ueshima, Ozawa， Chiba对一些原始无脊椎动物如腕足类和潜行海麻类进行了DNA分析，在更高的分类水平上建立了它们的系统发育关系。(4)理论研究：Chiba基于数量遗传学理论构建了数值模型来解释长期表型水平的进化。

(1) Ecological and taxonomic research : Kase, Hayami, Hanai, Tabuki, and Mori have found a peculiar primitive invertebrate faunas in the submarine caves in the tropical and subtropical Western Pacific. They collected many live and dead samples of the faunas and analyzed their ecological and taxonomic characteristic as a basis for future evolutionary researches.(2) Developmental biological research : Tanabe has investigated the mode of embryonic shell development in the primitive ectocochliate cephalopod Nautilus with the help of Mr. K.Uchiyama of the Toba Aquarium, and recognized a disks-shaped univalved organic shell (cicatrix) in the early stage. A similar shaped disk-shaped or low cap shaped primary shell is also known in extant Monoplacophora, suggesting their phylogenetic relationships.(3) Molecular systematic research : Endo, Ueshima, Ozawa, and Chiba have conducted DNA analysis of some primitive invertebrates such as brachiopods and stalked crinoids to establish their phylogenetic relationships at higher taxonomic levels.(4) Theoretical research : Chiba constructed numerical models to explain the log-term phenotypic-level evolution based on the theory of quantitative genetics.