ABSTRACT

Late Oligocene caviomorphs represent one of the most important early adaptive radiations of this group of rodents. They show a high taxonomic diversity and a wide geographic distribution, with those found in the upper Oligocene of Salla (Bolivia) and Patagonia (Argentina) being particularly diverse. However, caviomorphs from the Deseadan South American Land Mammal Age in other latitudes are still scarcely known. In this contribution, we describe new caviomorph rodents from the Deseadan levels of Quebrada Fiera locality (Mendoza Province; central-western Argentina) and evaluate their systematic and paleobiogeographic significance. The taxonomic composition of the caviomorphs from Quebrada Fiera reveals a complex biogeographic history, as we recognize one endemic Cavioidea (Asteromys puelche sp. nov.) and two Chinchilloidea: one with Patagonian affinities (Cephalomys sp.) and another with a wide distribution in South America (Incamys bolivianus). Asteromys puelche sp. nov., shows closer phylogenetic affinities with the Bolivian A. bolivianus than with the Patagonian A. punctus. These rodents, in common with the whole mammalian association from Quebrada Fiera, show a mix of endemic taxa and others shared with higher and lower latitudes.

摘要

晚渐新世 caviomorphs 代表了这组啮齿动物最重要的早期适应性辐射之一。它们显示出高度的分类多样性和广泛的地理分布，其中在萨拉（玻利维亚）和巴塔哥尼亚（阿根廷）的渐新世上层发现的物种特别多样化。然而，来自其他纬度的 Deseadan 南美陆地哺乳动物时代的腔形动物仍然鲜为人知。在这篇文章中，我们描述了来自 Quebrada Fiera 地区（门多萨省；阿根廷中西部）的 Deseadan 级别的新 caviomorph 啮齿动物，并评估了它们的系统和古生物地理意义。来自 Quebrada Fiera 的 caviomorphs 的分类组成揭示了复杂的生物地理历史，因为我们认识到一种地方性 Cavioidea ( Asteromys puelchesp. nov.) 和两种龙猫亚目：一种与巴塔哥尼亚有亲缘关系（Cephalomys sp. ），另一种在南美洲广泛分布（Incamys bolivianus）。Asteromys puelche sp. 11 月，显示与玻利维亚A. bolivianus 的亲缘关系比与 Patagonian A. punctus 的亲缘关系更近。这些啮齿动物与 Quebrada Fiera 的整个哺乳动物协会一样，表现出地方性分类群和与高纬度和低纬度共享的其他类群的混合。