Evolution of river dolphins
Evolution of river dolphins
复制标题
DOI：
10.1098/rspb.2000.1385
复制
发表时间：
2001-03-07
影响因子：
4.7
通讯作者：
Brownell, RL
中科院分区：
文献类型：
--
作者：
Hamilton, H;Caballero, S;Brownell, RL
世界上的河豚（Inia，Pontoporia，Lipotes和Platanista）是所有鲸目动物中最不为人所知和最濒危的。这四个现存的属栖息在地理上分离的河流系统，并表现出高度修改的形态，导致许多鲸类学家把河豚作为一个非自然的群体。许多安排已经提出了他们的系统发育关系，彼此和其他齿鲸类。这些不同的观点强烈影响了重要的，虽然有限的，江豚化石记录所提出的地理和进化意义。我们提出了一个假设的河流海豚关系的基础上的系统发育分析的三个线粒体基因的29种鲸类，得出的结论是，四个属代表三个独立的，古老的分支齿鲸类进化。我们的分子进化与现代齿鲸类的主要谱系的第一个化石外观相对应。结合第三纪古海洋学中的相关事件，我们发展了一个情景，在全球高海平面的中新世中期的海豚进化。我们认为，祖先的四个现存的海豚血统殖民浅陆表海淹没亚马逊河，巴拉那河，长江和印度-恒河流域，随后留在这些广泛的水道在过渡到淡水与晚新第三纪的海平面下降的趋势。
The world's river dolphins (Inia, Pontoporia, Lipotes and Platanista) are among the least known and most endangered of all cetaceans. The four extant genera inhabit geographically disjunct river systems and exhibit highly modified morphologies, leading many cetologists to regard river dolphins as an unnatural group. Numerous arrangements have been proposed for their phylogenetic relationships to one another and to other odontocete cetaceans. These alternative views strongly affect the biogeographical and evolutionary implications raised by the important, although limited, fossil record of river dolphins. We present a hypothesis of river dolphin relationships based on phylogenetic analysis of three mitochondrial genes for 29 cetacean species, concluding that the four genera represent three separate, ancient branches in odontocete evolution. Our molecular phylogeny corresponds well with the first fossil appearances of the primary lineages of modern odontocetes. Integrating relevant events in Tertiary palaeoceanography, we develop a scenario far river dolphin evolution during the globally high sea levels of the Middle Miocene. We suggest that ancestors of the four extant river dolphin lineages colonized the shallow epicontinental seas that inundated the Amazon, Parana, Yangtze and Indo-Gangetic river basins, subsequently remaining in these extensive waterways during their transition to freshwater with the Late Neogene trend of sea-level lowering.