Universidad de Alcalá, GloCEE - Global Change Ecology and Evolution Research Group, Departamento de Ciencias de la Vida, Madrid, Spain.
School of Earth Sciences, University of Bristol, Wills Memorial Building, Bristol, UK.
Nat Ecol Evol. 2021 Sep;5(9):1266-1272. doi: 10.1038/s41559-021-01498-w. Epub 2021 Jul 1.
Proboscideans were keystone Cenozoic megaherbivores and present a highly relevant case study to frame the timing and magnitude of recent megafauna extinctions against long-term macroevolutionary patterns. By surveying the entire proboscidean fossil history using model-based approaches, we show that the dramatic Miocene explosion of proboscidean functional diversity was triggered by their biogeographical expansion beyond Africa. Ecomorphological innovations drove niche differentiation; communities that accommodated several disparate proboscidean species in sympatry became commonplace. The first burst of extinctions took place in the late Miocene, approximately 7 million years ago (Ma). Importantly, this and subsequent extinction trends showed high ecomorphological selectivity and went hand in hand with palaeoclimate dynamics. The global extirpation of proboscideans began escalating from 3 Ma with further extinctions in Eurasia and then a dramatic increase in African extinctions at 2.4 Ma. Overhunting by humans may have served as a final double jeopardy in the late Pleistocene after climate-triggered extinction trends that began long before hominins evolved suitable hunting capabilities.
长鼻目动物是新生代的巨型食草动物，是一个非常重要的案例研究，可以根据长期的宏观进化模式来确定最近巨型动物灭绝的时间和规模。通过使用基于模型的方法调查整个长鼻目动物的化石历史，我们表明，长鼻目动物功能多样性在中新世的剧烈爆发是由它们在非洲以外的生物地理扩张引发的。生态形态创新推动了生态位分化；容纳几种不同长鼻目动物在同域的社区变得很常见。第一次灭绝发生在大约 700 万年前的中新世晚期。重要的是，这一趋势以及随后的灭绝趋势表现出了高度的生态形态选择性，并与古气候动态密切相关。从 300 万年前开始，长鼻目动物在全球范围内逐渐灭绝，随后在欧亚大陆的灭绝进一步加剧，而在 240 万年前，非洲的灭绝急剧增加。在人类开始具备合适的狩猎能力之前很久，气候引发的灭绝趋势就已经开始了，在更新世晚期，人类过度狩猎可能是长鼻目动物灭绝的最后一个双重打击。
