Iterative evolution of large-bodied hypercarnivory in canids benefits species but not clades
Iterative evolution of large-bodied hypercarnivory in canids benefits species but not clades
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DOI：
10.1038/s42003-020-01193-9
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发表时间：
2020-08-21
影响因子：
5.9
通讯作者：
Van Valkenburgh, Blaire
中科院分区：
文献类型：
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作者：
Balisi, Mairin A.;Van Valkenburgh, Blaire
生态专业化在不同的尺度上都有成本和收益：对个体有利的特征可能对种群、物种或进化支不利。特别是，哺乳动物的大体型和高食肉性（饮食中70%以上是肉类）反复进化；然而，大型超级食肉动物被认为陷入了宏观进化的“棘轮”，单方面走向衰落。在这里，我们利用北美犬科动物（狗）丰富的化石记录来衡量这种专业化对灭绝风险的影响。在过去的4000万年中，在三个犬科亚科中的两个亚科中，大型超食肉动物的多样化似乎在进化水平上受到限制，使专门的谱系倾向于灭绝。然而，尽管物种存续时间较短，但大型超级食肉动物的灭绝率与所有其他犬科动物的灭绝率基本相似。只有在11000年前的更新世末期，大型超级食肉动物的灭绝是由体型和食肉动物选择的，这表明在人类活动影响之前，大型超级食肉动物在物种水平上并不处于劣势。Balisi和Van Valkenburgh分析了体型和饮食专门化对北美犬科动物灭绝机制的影响。他们发现，多次独立进化的超级食肉动物不会增加物种灭绝，但与进化枝的灭绝有关。
Ecological specialization has costs and benefits at various scales: traits benefitting an individual may disadvantage its population, species or clade. In particular, large body size and hypercarnivory (diet over 70% meat) have evolved repeatedly in mammals; yet large hypercarnivores are thought to be trapped in a macroevolutionary "ratchet", marching unilaterally toward decline. Here, we weigh the impact of this specialization on extinction risk using the rich fossil record of North American canids (dogs). In two of three canid subfamilies over the past 40 million years, diversification of large-bodied hypercarnivores appears constrained at the clade level, biasing specialized lineages to extinction. However, despite shorter species durations, extinction rates of large hypercarnivores have been mostly similar to those of all other canids. Extinction was size- and carnivory-selective only at the end of the Pleistocene epoch 11,000 years ago, suggesting that large hypercarnivores were not disadvantaged at the species level before anthropogenic influence. Balisi and Van Valkenburgh analyse the effect of body size and dietary specialization on extinction regimes in North American Canidae. They find that hypercarnivory, which evolved independently multiple times, does not increase species-level extinction but is associated with extinctions of clades.