Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.
PLoS One. 2013;8(4):e59668. doi: 10.1371/journal.pone.0059668. Epub 2013 Apr 3.
Although species within Lagomorpha are derived from a common ancestor, the distribution range and body size of its two extant groups, ochotonids and leporids, are quite differentiated. It is unclear what has driven their disparate evolutionary history. In this study, we compile and update all fossil records of Lagomorpha for the first time, to trace the evolutionary processes and infer their evolutionary history using mitochondrial genes, body length and distribution of extant species. We also compare the forage selection of extant species, which offers an insight into their future prospects. The earliest lagomorphs originated in Asia and later diversified in different continents. Within ochotonids, more than 20 genera occupied the period from the early Miocene to middle Miocene, whereas most of them became extinct during the transition from the Miocene to Pliocene. The peak diversity of the leporids occurred during the Miocene to Pliocene transition, while their diversity dramatically decreased in the late Quaternary. Mantel tests identified a positive correlation between body length and phylogenetic distance of lagomorphs. The body length of extant ochotonids shows a normal distribution, while the body length of extant leporids displays a non-normal pattern. We also find that the forage selection of extant pikas features a strong preference for C(3) plants, while for the diet of leporids, more than 16% of plant species are identified as C(4) (31% species are from Poaceae). The ability of several leporid species to consume C(4) plants is likely to result in their size increase and range expansion, most notably in Lepus. Expansion of C(4) plants in the late Miocene, the so-called 'nature's green revolution', induced by global environmental change, is suggested to be one of the major 'ecological opportunities', which probably drove large-scale extinction and range contraction of ochotonids, but inversely promoted diversification and range expansion of leporids.
尽管兔形目物种起源于一个共同的祖先，但现存的两个分支——鼠兔和兔——的分布范围和体型差异很大。目前尚不清楚是什么导致了它们截然不同的进化历史。在这项研究中，我们首次编译和更新了所有兔形目化石记录，以追踪其进化过程，并利用线粒体基因、现存物种的体长和分布来推断其进化历史。我们还比较了现存物种的觅食选择，这为它们的未来前景提供了一些启示。最早的兔形目动物起源于亚洲，后来在不同的大陆上多样化。在鼠兔中，有 20 多个属在早中新世到中中新世期间存在，而其中大多数在从中新世到上新世的过渡时期灭绝。兔的多样性高峰出现在中新世到上新世的过渡时期，而它们的多样性在第四纪晚期急剧下降。Mantel 检验确定了兔形目动物的体长与系统发育距离之间存在正相关关系。现存鼠兔的体长呈正态分布，而现存兔的体长呈非正态分布。我们还发现，现存鼠兔的觅食选择表现出对 C(3)植物的强烈偏好，而对于兔的饮食，超过 16%的植物物种被鉴定为 C(4)(其中 31%来自禾本科)。一些兔属物种能够食用 C(4)植物，这可能导致它们的体型增大和分布范围扩大，尤其是在兔属中。晚中新世 C(4)植物的扩张，即所谓的“大自然的绿色革命”，是由全球环境变化引起的，被认为是主要的“生态机遇”之一，这可能导致了鼠兔的大规模灭绝和分布范围的收缩，但反过来又促进了兔的多样化和分布范围的扩大。
