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Validity and historical process of formation of the center of endemism for reptiles in the southern Tokara Islands

吐噶喇群岛南部爬行动物特有中心的有效性及其形成的历史过程

基本信息

批准号：
11833013
负责人：
OTA Hidetoshi
金额：
$ 2.11万
依托单位：
University of the Ryukyus
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-11833013/
关键词：
Reptiles Insular isolation Speciation Genetic differentiation Phenetic differentiation Biogeography Taxonomy Tokora Islands

项目摘要

Three islands of the Tokara Group (Takarajima, Kodakarajima and Kojima), located on the southwestern side of the Tokara Tectonic Strait, are known to accommodate, despite their small areas and low environmental diversities, a group of terrestrial animals that are taxonomically recognized as endemic species. Using the reptiles as a model group, we examined the validity of such a taxonomic view from a phylogenetic standpoint. We also inferred the process. Of formation of such a characteristic fauna in the southern Tokara islands. We conducted molecular phylogenetic analyses for three lineages: (1)Trimeresurus tokarensis, a species endemic to the southern Tokara islands, and T. flavoviridis, a close relative of the former, from the Amami and the Okinawa Groups; (2) Cyclophiops semicarinatus from the southern Tokara Islands, where the species is know to have reduced its body size, and from the Amami and the Okinawa Groups; and (3) a putative undescribed species of the genus Gekko endemic to the southern Tokara islands, and its closest relatives, G. hokouensis and G. yakuensis from the neighboring islands. Of these, lineages (1) and (2) shared a same phylogeographical pattern, (southern Tokara Amami) Okinawa, and very small genetic distances between the former two island groups. The lineage (3), on the other hand, showed a distinct differentiation between representatives from the southern Tokara and other areas. These results suggest that the southern Tokara has been serving as a site for long isolation for some terrestrial organisms, giving rise to phylogenetically distinct entities (as represented by Gekko sp.) on the one hand, and also acted as a site for rapid phenetic changes possibly under extreme insular environments on the other hand.

托卡拉群岛的三个岛屿(多卡拉岛、哥达卡拉岛和小岛)位于托卡拉构造海峡的西南侧，尽管其面积小、环境多样性低，但已知容纳了一群在分类学上被确认为特有物种的陆地动物。以爬行动物为模型组，从系统发育的角度检验了这种分类学观点的有效性。我们还推断了这一过程。在托卡拉群岛南部形成这种特有的动物群的可能性。我们对三个谱系进行了分子系统发育分析：(1)托卡拉群岛南部特有的Trimeresurus tokarensis，以及前者的近亲黄绿色Trimeresurus，来自Amami和冲绳群；(2)来自托卡拉群岛南部的半环蛇，已知该物种已经缩小了身体尺寸，来自Amami和冲绳群；以及(3)一个可能的未描述的壁虎属物种，特有于托卡拉群岛南部，以及它的近亲G.hokouensis和G.yakuensis来自邻近岛屿。其中，血统(1)和(2)具有相同的系统地理模式，(南托卡拉Amami)冲绳，前两个岛群之间的遗传距离非常小。另一方面，血统(3)显示了来自托卡拉南部和其他地区的代表之间的明显区别。这些结果表明，托卡拉南部一直是一些陆地生物长期隔离的场所，产生了系统发育上截然不同的实体(以壁虎为代表)。一方面，也是在极端的岛国环境下可能发生的快速表型变化的场所。