Study on morphology, ecology, biogeography and systematics of primitive ostracod Platycopa

原始介形类扁形动物的形态、生态、生物地理学和系统学研究

基本信息

批准号：
11640693
负责人：
TSUKAGOSHI Akira
金额：
$ 2.3万
依托单位：
Shizuoka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11640693/
关键词：
Ostracoda Crustacea Living fossil Evolution Ontogeny Comparative anatomy Ostracoda ベントス segmentation living fossil Benthos 個体発生 Ostraconda Segmentation Bonthos

项目摘要

This research focused on Keijcyoidea sp. which is a taxon of primitive ostracod Platycopa from Japan.There is no report on the ecology and habitat of Platycopa at all. In the experience, the largest number of individuals were collected from the sediments which attached around the rhizoid of Eisenia bicyclis. In order to know the habitat and behavior in detail, some living specimens were observed. As a result, the following facts became clear : they use only antennule, antenna and furcae for moving ; their habitat in not surface but between coarse sand grains. It is suggested that other Platycopa species must have almost the same life style because the basic body plan of them is common to the Keijcyoidea spThe following points of ontogeny and comparative anatomy were made clear. These knowledge will support the understandings of evolution on the primitive ostracod Platycopa.1) They have 9 instars in ontogeny. 2) Copulatory organs of both sexes appear in A-3 (6th instar) as anlagen and the sexual dimorphism is observed in and after this stage. 3) Diagnostic characters of this taxon e.g. articulate trunk, bi-ramous antenna appear in the early stages. 4) They have nauplius eyes. 5) the anal opening are located at not dorsal side but ventral side. 6) An unit exists after the anal segment ; it is a telson. 7) The telson derives a pair of limb-like organ 'furcae' which is not homologous to 'caudal rami' in Podocopina. 8) furcae continue to develop until the final moult. 9) The copulatory organs of both sexes are derived from the 4th trunk segment.

这项研究的重点是Keijcyoidea sp。这是日本原始的Ostracod Platycopa的分类群。根据这一经验，最大的个体是从艾塞尼亚自行车的根茎附属的沉积物中收集的。为了详细了解栖息地和行为，观察到了一些生物标本。结果，以下事实变得清晰：它们仅使用天线，天线和furcae移动；它们的栖息地不是表面，而是在粗砂之间。建议其他铂谷物种必须具有几乎相同的生活方式，因为它们的基本身体计划是keijcyoidea sps sp的共同点，这是个体发育和比较解剖结构的以下几点。这些知识将支持对原始的ostracod platycopa的进化的理解。1）它们具有9龄的构想。 2）两性的交配器官出现在A-3（第六龄）中，作为Anlagen，并且在此阶段和之后观察到了性二态性。 3）此分类单元的诊断特征，例如表达的躯干，双痕的天线出现在早期阶段。 4）他们的眼睛是奈普利乌斯的。 5）肛门开口位于不背侧，而是腹侧。 6）在肛门段之后存在一个单元；这是Telson。 7）Telson衍生了一对类似肢体的器官“ Furcae”，与Podocopina中的“尾拉米”同源。 8）Furcae继续发展到最后的换羽。 9）两个性别的交配器官均来自第四个树干段。