Ecology and Evolutionary Biology, University of California Santa Cruz , 130 McAllister Way, Santa Cruz, CA 95060 , USA.
Biol Lett. 2019 May 31;15(5):20190155. doi: 10.1098/rsbl.2019.0155. Epub 2019 May 29.
Environmental changes can lead to evolutionary shifts in phenotypic traits, which in turn facilitate the exploitation of novel adaptive landscapes and lineage diversification. The global cooling, increased aridity and expansion of open grasslands during the past 50 Myr are prime examples of new adaptive landscapes that spurred lineage and ecomorphological diversity of several mammalian lineages such as rodents and large herbivorous megafauna. However, whether these environmental changes facilitated evolutionary shifts in small- to mid-sized predator morphology is unknown. Here, I used a complete cranial and body morphological dataset to examine the timing of evolutionary shifts in cranial shape, body size and body shape within extant mustelids (martens, otters, polecats and weasels) during the climatic and environmental changes of the Cenozoic. I found that evolutionary shifts in all three traits occurred within extant mustelid subclades just after the onset of the Mid-Miocene Climate Transition. These mustelid subclades first shifted towards more elongate body plans followed by concurrent shifts towards smaller body sizes and more robust crania. I hypothesize that these cranial and body morphological shifts enabled mustelids to exploit novel adaptive zones associated with the climatic and environmental changes of the Mid to Late Miocene, which facilitated significant increases in clade carrying capacity.
环境变化可导致表型特征的进化转变，进而促进对新适应景观和谱系多样化的利用。过去 5000 万年中，全球变冷、干旱加剧和开阔草原扩张就是新适应景观的主要例子，这些变化刺激了啮齿类动物和大型草食性巨型动物等多个哺乳动物谱系的谱系和生态形态多样性。然而，这些环境变化是否促进了中小体型捕食者形态的进化转变尚不清楚。在这里，我使用了一个完整的颅面和身体形态数据集，来研究在新生代气候和环境变化期间，现存鼬科（貂、水獭、白鼬和黄鼠狼）的颅形、体型和身体形态的进化转变的时间。我发现，这三个特征的进化转变都发生在中中新世气候转变开始后不久的现存鼬科亚科内。这些鼬科亚科首先向更长的身体计划转变，然后同时向更小的体型和更粗壮的颅骨转变。我假设，这些颅面和身体形态的转变使鼬科能够利用与中到晚中新世气候和环境变化相关的新的适应区，从而极大地增加了谱系的承载能力。
