DeMIGUEL Daniel, Azanza Beatriz, Morales Jorge
Catalan Institute of Paleontology Miquel Crusafont, Autonomus University of Barcelona, Barcelona, Spain.
Integr Zool. 2014 Aug;9(4):412-33. doi: 10.1111/1749-4877.12080.
Key innovations are newly acquired structures that permit the performance of a new function and open new adaptive zones, and are, therefore, of paramount significance for understanding the history of the Ruminantia, particularly its diversification through the Miocene. Here we review and discuss what is known about these evolutionary novelties, with special emphasis on the appearance and evolution of cranial appendages and high-crowned (or hypsodont) teeth. Cranial appendages probably favored the diversification of pecorans by being structures strongly related to sexual selection, whereas the acquisition of hypsodont teeth could have expanded potential dietary breadth and allowed species to extend diets into the grazing range without eliminating browsing as a potential diet. When analyzed in conjunction with patterns of faunal diversity and in the context of climatic changes, it seems that the overall view that ruminant cranial appendages and hypsodonty may have started responding to increased patterns of seasonality and the opening-up of ecosystems is roughly valid. Instead, they occurred through several distinct pulses and varied widely among continents. This review is, to our knowledge, the first to highlight that the evolution of these innovations has been far from constant and uniform through time. Furthermore, we identify that both a first attempt to increase hypsodonty starting in the early Miocene and a first evolution of antlers and pronghorns were interrupted as a consequence of wide climatic fluctuations in the early-middle Miocene transition.
关键创新是新获得的结构，这些结构能够实现新功能并开辟新的适应区，因此对于理解反刍亚目动物的演化历史，尤其是其在中新世的多样化过程具有至关重要的意义。在此，我们回顾并讨论关于这些进化新特征的已知信息，特别强调颅骨附属物和高冠（或高齿冠）牙齿的出现与演化。颅骨附属物可能通过与性选择密切相关的结构促进了牛型亚目的多样化，而高齿冠牙齿的获得可能扩大了潜在的食物范围，并使物种能够将食物范围扩展到放牧范围，同时又不排除啃食作为一种潜在的食物来源。当结合动物群多样性模式以及气候变化背景进行分析时，反刍动物的颅骨附属物和高齿冠特征可能已开始对季节性增强和生态系统开放做出反应这一总体观点似乎大致正确。然而，它们是通过几个不同的阶段出现的，并且在各大洲之间差异很大。据我们所知，这篇综述首次强调这些创新特征的演化在时间上远非持续和一致的。此外，我们发现，由于中新世早期到中期过渡期间广泛的气候波动，始于中新世早期的首次高齿冠化尝试以及鹿角和叉角羚的首次演化都被中断了。
