The Late Permian herbivore Suminia and the early evolution of arboreality in terrestrial vertebrate ecosystems
The Late Permian herbivore Suminia and the early evolution of arboreality in terrestrial vertebrate ecosystems
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DOI：
10.1098/rspb.2009.0911
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发表时间：
2009-10-22
影响因子：
4.7
通讯作者：
Reisz, Robert R.
中科院分区：
文献类型：
--
作者：
Froebisch, Joerg;Reisz, Robert R.
脊椎动物在陆地上的历史中多次填充和划分了陆地生态系统，并且能够占据新的、以前未开发的栖息地。树栖生态空间在脊椎动物进化中尤为重要，因为它提供了新的食物资源并保护其免受大型地面捕食者的侵害。我们研究了二叠纪晚期（约 260 Ma）草食性突触动物 Suminia getmanovi 的骨骼解剖结构，并对多种现存和灭绝的陆地和树栖四足动物的指骨比例进行了形态测量分析，以辨别化石类群（特别是苏米尼亚）的运动功能和栖息地偏好。苏米尼亚的颅后解剖学为脊椎动物的抓握能力和树栖性提供了最早的骨骼证据，如其细长的四肢、固有的指骨比例、发散的第一个手指和潜在的可抓握的尾巴所表明的。形态测量分析进一步表明树栖脊椎动物的抓握和粘附形态类型之间存在差异，前者表现出近端指骨伸长，后者表现出倒数第二指骨伸长。包括苏米尼亚在内的化石组合表明，树木栖息和资源分配是在现代陆地脊椎动物生态系统最初建立后不久发生的，有大量的初级消费者和少数顶级捕食者。
Vertebrates have repeatedly filled and partitioned the terrestrial ecosystem, and have been able to occupy new, previously unexplored habitats throughout their history on land. The arboreal ecospace is particularly important in vertebrate evolution because it provides new food resources and protection from large ground-dwelling predators. We investigated the skeletal anatomy of the Late Permian (approx. 260 Ma) herbivorous synapsid Suminia getmanovi and performed a morphometric analysis of the phalangeal proportions of a great variety of extant and extinct terrestrial and arboreal tetrapods to discern locomotor function and habitat preference in fossil taxa, with special reference to Suminia. The postcranial anatomy of Suminia provides the earliest skeletal evidence for prehensile abilities and arboreality in vertebrates, as indicated by its elongate limbs, intrinsic phalangeal proportions, a divergent first digit and potentially prehensile tail. The morphometric analysis further suggests a differentiation between grasping and clinging morphotypes among arboreal vertebrates, the former displaying elongated proximal phalanges and the latter showing an elongation of the penultimate phalanges. The fossil assemblage that includes Suminia demonstrates that arboreality and resource partitioning occurred shortly after the initial establishment of the modern type of terrestrial vertebrate ecosystems, with a large number of primary consumers and few top predators.