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Proterotheriids and macraucheniids (Litopterna: Mammalia) from the Pampa Castillo Fauna, Chile (early Miocene, Santacrucian SALMA) and a new phylogeny of Proterotheriidae
Journal of Systematic Palaeontology ( IF 2.6 ) Pub Date : 2019-09-23 , DOI: 10.1080/14772019.2019.1662500
Andrew J. McGrath 1 , John J. Flynn 2 , André R. Wyss 1
Affiliation  

Here we describe the litopterns, a diverse and temporally long-ranging clade of South American native ‘ungulates’, of the early Miocene Pampa Castillo fauna from the Galera Formation in the Andean Cordillera of southern Chile, and present a new phylogeny of Proterotheriidae, the most speciose litoptern subgroup. Two proterotheriids occur at Pampa Castillo: Thoatherium, the northernmost and first record of this taxon outside Santa Cruz Province, Argentina, and Picturotherium, known previously solely from the Pinturas Formation of north-western Santa Cruz Province. Macraucheniidae are represented at Pampa Castillo by Theosodon. Collectively, these three taxa suggest an early Miocene (Santacrucian South American Land Mammal ‘Age’ (SALMA)) age for the fossil mammal fauna from Pampa Castillo, reinforcing previous biochronological interpretations. Results of a comprehensive phylogenetic analysis identify Megadolodus molariformis as the earliest-diverging member of Proterotheriidae, a name for which we propose a stem-based definition. Few multi-species proterotheriid genera were recovered as monophyletic in our analysis. Three ‘anisolambdid’ litopterns, initially assumed to represent outgroups, instead nest deeply within Proterotheriidae, implying long ghost lineages. The phylogenetic placement of the four proterotheriids from the middle Miocene La Venta fauna of Colombia sheds light on the poorly understood long-term isolation of tropical faunas and their degree of exchange with high-latitude regions. Santacrucian SALMA assemblages in Patagonia are notable in that older localities preferentially produce earlier-diverging proterotheriids. Older sites are also marked by a mix of brachyodont and hypsodont taxa, whereas younger sites yield strictly hypsodont forms, supporting the notion of increasing aridity in Patagonia through this interval. Proterotheriids alone cannot be used to discriminate between an early or late Santacrucian age for the Pampa Castillo fauna, but the brachyodonty of Picturotherium suggests a humid climate and closed habitats.



中文翻译:

智利Pampa Castillo动物区系(早期中新世,Santacrucian SALMA)的Proterotheriids和macraucheniids(Litopterna:哺乳动物)和Proterotheriidae的一个新的系统发育

在这里,我们描述了来自南部智利安第斯山脉山脉加莱拉形成的中新世潘帕·卡斯蒂略动物区的直翅类动物,这是南美本土“有蹄类动物”的一个多样的,时间上很长的进化枝,并提出了一种新的Proterotheriidae的系统发育史。最特殊的鳞翅目亚组。潘帕卡斯蒂略(Pampa Castillo)发生两种前列腺炎:Thoatherium,此分类单元的最北端和第一记录,位于阿根廷圣克鲁斯省以外;以及Picturotherium,以前仅从西北圣克鲁斯省的Pinturas地层中知道。Macraucheniidae由Theosodon代表在Pampa Castillo。总的来说,这三个分类群暗示了潘帕卡斯蒂略的化石哺乳动物群的中新世(南极南美南美哺乳动物“年龄”(SALMA))年龄,这加强了以前的生物年代学解释。全面的系统发育分析结果可鉴定出摩加多角molar作为Proterotheriidae最早的成员,我们建议使用基于茎的定义的名称。在我们的分析中,很少有多物种的前列腺素属被发现为单系的。最初假定是代表外群的三个“ anisolambdid”小鳞翅目,而是深深地嵌套在Proterotheriidae内,暗示着长长的幽灵血统。哥伦比亚中新世中部La Venta中部动物群中的4种前体兽类的系统发育定位为人们对热带动物群长期孤立的了解以及它们与高纬度地区的交换程度提供了启示。巴塔哥尼亚的Santacrucian SALMA组合值得注意的是,较老的地区优先生产较早分散的前列腺素。较旧的地点还以曲奇鱼和拟南芥类群的混合为特征,而较年轻的地点则严格产生了假牙的形式,在此间隔内,巴塔哥尼亚的干旱日益增加。潘塔·卡斯蒂略动物区系不能单独使用前列腺素类动物来区分圣塔克鲁斯时代的晚期。Picturotherium提示气候潮湿,栖息地封闭。

更新日期:2020-04-01
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