ABSTRACT

Interatheriinae is one of the most derived subfamilies of South American notoungulates. Several interatheriines have been described since the 19th century, but most of them have not been revised, or been formally re-examined, for more than a century. Most interatheriine taxa were erected based on materials collected from Argentinean Patagonia, particularly from the Santa Cruz Formation (early–middle Miocene), Santa Cruz Province. Within the framework of an exhaustive unpublished systematic revision of Interatheriinae (early Oligocene–late Miocene), we studied the holotype of Santacrucian Icochilus undulatus, leading to the recognition of a new monospecific genus, Neoicochilus gen. nov., and the new combination N. undulatus. In addition, we formalize the taxonomic revision of Cochilius, proposing the following: Paracochilius is the junior synonym of Cochilius; Cochilius consists of C. volvens, C. fumensis, and C. brevirostrus; Paracochilius chubutensis and Protypotherium minor are junior synonyms of Cochilius brevirostrus; Cochilius pendens is the junior synonym of Cochilius columnifer; and the holotype of Cochilius columnifer exhibits the diagnostic features of Protypotherium, so we propose the new combination Protypotherium columnifer, pending publication of our thorough taxonomic revision of Protypotherium. Our taxonomic scheme is supported by a cladistic analysis, which places Neoicochilus undulatus in a derived position within Interatheriinae, as the sister taxon of the monophyletic genus Cochilius, and the clade Neoicochilus plus Cochilius positioned as the sister taxon of Interatherium. Our phylogenetic results support the monophyly of Miocene interatheriines.

摘要

Interatheriinae 是南美有蹄类动物最衍生的亚科之一。自 19 世纪以来，已经描述了几个 interatheriines，但其中大部分都没有被修订或正式重新审查，一个多世纪以来。大多数interatheriine 分类群是根据从阿根廷巴塔哥尼亚收集的材料建立的，特别是从圣克鲁斯省的圣克鲁斯组（早中新世）收集的材料。在对 Interatheriinae（早渐新世 - 晚中新世）的详尽未发表的系统修订的框架内，我们研究了 Santacrucian Icochilus undulatus 的正模标本，从而识别出一个新的单种属，Neoicochilus gen。11 月，以及新组合N. undulatus. 此外，我们正式的分类修订Cochilius，提出以下：Paracochilius是的异名Cochilius ; Cochilius由C. volvens、C. fumensis和C. brevirostrus 组成；Paracochilius chubutensis和Protypotherium minor是Cochilius brevirostrus 的初级同义词；Cochilius决案件是的同物异名Cochilius columnifer ; 和的正模Cochilius columnifer表现出的诊断特征Protypotherium，因此我们提出了新的组合Protypotherium columnifer，等待我们对Protypotherium 的彻底分类学修订版的发布。我们的分类方案是由一个分支分析，哪些地方支持Neoicochilus波状的内Interatheriinae派生位置，为单系属的姐妹类群Cochilius和进化枝Neoicochilus加Cochilius定位为姐妹类群Interatherium。我们的系统发育结果支持中新世 interatheriines 的单系。