Dispersal is a major driver of the latitudinal diversity gradient of Carnivora
Dispersal is a major driver of the latitudinal diversity gradient of Carnivora
复制标题
扩散是食肉目纬度多样性梯度的主要驱动因素
DOI：
10.1111/geb.12354
复制
发表时间：
2015
影响因子：
6.4
通讯作者：
H. Morlon
中科院分区：
文献类型：
--
作者：
J. Rolland;F. Condamine;Champak R. Beeravolu;F. Jiguet;H. Morlon
目的
物种地理学的一个主要目标是了解多样化率（物种形成和灭绝）和扩散在形成纬度多样性梯度（物种丰富度随纬度增加而减少）方面的相对贡献。食肉目哺乳动物，其中包括286种，显示了传统的纬度多样性梯度看到几乎所有的哺乳动物的订单。然而，热带地区物种丰富度高的驱动过程可能与其他哺乳动物群体有着根本的不同。事实上，最近的一项研究表明，食肉目与所有其他主要哺乳动物目不同，热带地区的净多样化率并不比温带地区高。因此，我们的目标是了解为什么热带地区有更多的食肉动物物种。
位置
全世界。
方法
我们重建了食肉动物的地理历史，使用时间校准的进化枝，包括所有陆生物种和扩散灭绝的分支模型。我们还分析了食肉动物属的化石数据集，以研究食肉动物的纬度分布如何随时间而变化。
结果
我们的地理分析表明，食肉目起源于古近纪早期的东古北界（即中国中亚）。多个独立的谱系沿着三条主要路径分散到低纬度地区：向非洲，向印度/东南亚和通过白令海峡向南美洲。这些扩散事件可能与高纬度地区的局部扩散有关。化石数据证实了该组的高纬度起源，随后在新近纪向低纬度地区的晚期扩散事件。
主要结论
不像大多数其他哺乳动物的订单，起源和多样化在低纬度和分散的“出热带”，食肉动物起源于高纬度，随后向南扩散。我们的研究提供了一个结合系统发育和化石数据的例子，以了解物种丰富度的全球范围的地理变化的产生和维持。
Aim
Understanding the relative contribution of diversification rates (speciation and extinction) and dispersal in the formation of the latitudinal diversity gradient – the decrease in species richness with increasing latitude – is a main goal of biogeography. The mammalian order Carnivora, which comprises 286 species, displays the traditional latitudinal diversity gradient seen in almost all mammalian orders. Yet the processes driving high species richness in the tropics may be fundamentally different in this group from that in other mammalian groups. Indeed, a recent study suggested that in Carnivora, unlike in all other major mammalian orders, net diversification rates are not higher in the tropics than in temperate regions. Our goal was thus to understand the reasons why there are more species of Carnivora in the tropics.
Location
World-wide.
Methods
We reconstructed the biogeographical history of Carnivora using a time-calibrated phylogeny of the clade comprising all terrestrial species and dispersal–extinction–cladogenesis models. We also analysed a fossil dataset of carnivoran genera to examine how the latitudinal distribution of Carnivora varied through time.
Results
Our biogeographical analyses suggest that Carnivora originated in the East Palaearctic (i.e. Central Asia, China) in the early Palaeogene. Multiple independent lineages dispersed to low latitudes following three main paths: toward Africa, toward India/Southeast Asia and toward South America via the Bering Strait. These dispersal events were probably associated with local extinctions at high latitudes. Fossil data corroborate a high-latitude origin of the group, followed by late dispersal events toward lower latitudes in the Neogene.
Main conclusions
Unlike most other mammalian orders, which originated and diversified at low latitudes and dispersed ‘out of the tropics’, Carnivora originated at high latitudes, and subsequently dispersed southward. Our study provides an example of combining phylogenetic and fossil data to understand the generation and maintenance of global-scale geographical variations in species richness.