Abstract：
New World porcupines (Erethizontinae) originated in South America and dispersed into North America as part of the Great American Biotic Interchange (GABI) 3-4 million years ago.1 Extant prehensile-tailed porcupines (Coendou) today live in tropical forests of Central and South America.2,3 In contrast, North American porcupines (Erethizon dorsatum) are thought to be ecologically adapted to higher-latitude temperate forests, with a larger body, shorter tail, and diet that includes bark.4,5,6,7 Limited fossils8,9,10,11,12,13 have hindered our understanding of the timing of this ecological differentiation relative to intercontinental dispersal during the GABI and expansion into temperate habitats.14,15,16,17,18 Here, we describe functionally important features of the skeleton of the extinct Erethizon poyeri, the oldest nearly complete porcupine skeleton documented from North America, found in the early Pleistocene of Florida. It differs from extant E. dorsatum in having a long, prehensile tail, grasping foot, and lacking dental specializations for bark gnawing, similar to tropical Coendou. Results from phylogenetic analysis suggest that the more arboreal characteristics found in E. poyeri are ancestral for erethizontines. Only after it expanded into temperate, Nearctic habitats did Erethizon acquire the characteristic features that it is known for today. When combined with molecular estimates of divergence times, results suggest that Erethizon was ecologically similar to a larger species of Coendou when it crossed the Isthmus of Panama by the early Pleistocene. It is likely that the range of this more tropically adapted form was limited to a continuous forested biome that extended from South America through the Gulf Coast.
摘要：
新世界豪猪（Erethizontinae）起源于南美，并在3-4百万年前作为美国大生物交换（GABI）的一部分分散到北美。1现存的全尾豪猪（Coendou）今天生活在中美洲和南美洲的热带森林中。北美豪猪（Erethizondorsatum）被认为在生态上适合高纬度的温带森林，一个更大的身体，较短的尾巴，和包括树皮的饮食4,5,6,7有限的化石8,9,10,11,12,13阻碍了我们对这种生态分化相对于GABI期间洲际扩散和向温带生境扩张的时间的理解。14,15,16,17,18这里，我们描述了已灭绝的Erethizonpoyeri骨骼的功能重要特征，北美记录的最古老的几乎完整的豪猪骨架，发现于佛罗里达早更新世。它不同于现存的E.dorsatum，牢牢的尾巴，抓着脚,缺乏牙齿咬树皮的专业，类似于热带Coendou。系统发育分析的结果表明，在E.poyeri中发现的更多树栖特征是erethiizontines的祖先。只有在它膨胀到温带之后，近地栖息地使Erethizon获得了今天众所周知的特征。当结合分子对发散时间的估计，结果表明，Erethizon在更新世早期穿越巴拿马地峡时，在生态上与较大的Coendou物种相似。这种更具热带适应性的形式的范围很可能仅限于从南美延伸到墨西哥湾沿岸的连续森林生物群落。
