Department of Anatomy, Case Western Reserve University, Cleveland, OH, USA
Department of Biology, Case Western Reserve University, Cleveland, OH, USA.
Proc Biol Sci. 2018 Jan 10;285(1870). doi: 10.1098/rspb.2017.2012.
This study investigates whether terrestrial mammalian carnivore guilds of ancient South America, which developed in relative isolation, were similar to those of other continents. We do so through analyses of clade diversification, ecomorphology and guild structure in the Sparassodonta, metatherians that were the predominant mammalian carnivores of pre-Pleistocene South America. Body mass and 16 characters of the dentition are used to quantify morphological diversity (disparity) in sparassodonts and to compare them to extant marsupial and placental carnivores and extinct North American carnivoramorphans. We also compare trophic diversity of the Early Miocene terrestrial carnivore guild of Santa Cruz, Argentina to that of 14 modern and fossil guilds from other continents. We find that sparassodonts had comparatively low ecomorphological disparity throughout their history and that South American carnivore palaeoguilds, as represented by that of Santa Cruz, Argentina, were unlike modern or fossil carnivore guilds of other continents in their lack of mesocarnivores and hypocarnivores. Our results add to a growing body of evidence highlighting non-analogue aspects of extinct South American mammals and illustrate the dramatic effects that historical contingency can have on the evolution of mammalian palaeocommunities.
本研究旨在探讨古代南美洲相对孤立发展的陆生哺乳动物食肉动物群是否与其他大陆的相似。我们通过对 Sparassodonta（南美史前主要的哺乳动物食肉动物）的分支多样性、生态形态和食性结构的分析来实现这一目标。Sparassodonta 的体型大小和 16 项牙齿特征被用来量化 Sparassodonta 的形态多样性（离散度），并将其与现生有袋类和胎盘类食肉动物以及已灭绝的北美的 Carnivoramorphans 进行比较。我们还比较了阿根廷圣克鲁斯的早中新世陆生食肉动物群与来自其他大陆的 14 个现代和化石食肉动物群的营养多样性。我们发现 Sparassodonta 在其整个历史中具有相对较低的生态形态多样性，并且代表阿根廷圣克鲁斯的南美食肉动物古群在缺乏中型食肉动物和低等食肉动物方面与其他大陆的现代或化石食肉动物群不同。我们的研究结果增加了越来越多的证据，强调了已灭绝的南美哺乳动物的非相似方面，并说明了历史偶然性对哺乳动物古群落进化的巨大影响。
