A new giant Purussaurus (Crocodyliformes, Alligatoridae) from the Upper Miocene Urumaco Formation, Venezuela
A new giant Purussaurus (Crocodyliformes, Alligatoridae) from the Upper Miocene Urumaco Formation, Venezuela
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DOI：
10.1017/s147720190600188x
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发表时间：
2006-09-01
影响因子：
2.6
通讯作者：
Riff, Douglas
中科院分区：
文献类型：
--
作者：
Aguilera, Orangel A.;Riff, Douglas
鳄鱼化石在南美洲的分类上是多种多样的，特别是在委内瑞拉的上中新世乌鲁马科组。其中包括巨型短吻鳄Purusourus，以前已知于巴西的上中新世Solimos组(P.brasilisis)和哥伦比亚的La Venta的中中新世(P.nevensis)。描述了乌鲁木科组鳄鱼的新标本，并建立了一新种--马兰代紫尾鳄。这是一个巨大的、细长的、极其平坦的头骨，一个非常大的鼻孔，几乎占喙长度的60%，以及一个巨大的尖孔，在第一颗下颌牙的颅窝之间向前延伸。米兰代紫苏(Purusourus mirandai sp.)11月是沼泽环境中最大的捕食者，代表了乌鲁马科群落的顶级营养水平。通过对68个鳄鱼类群164个性状的系统发育分析，支持Nevensis和P.mirandai的5种同源同源关系，并证实了该属与网尾鳄科的姐妹群关系。
Fossil Crocodylia are taxonomically diverse in South America, particularly in the upper Miocene Urumaco Formation (Venezuela). Among them is the giant alligatoroid Purussourus, previously known from the upper Miocene Solimoes Formation in Brasil (P. brasiliensis) and the middle Miocene of La Venta in Colombia (P. neivensis). New specimens of Crocodylia from the Urumaco Formation are described and a new species, Purussaurus mirandai, erected. This is characterised by a large, elongate and extremely flat skull, a very large narial opening comprising almost 60% of rostral length and a large incisive foramen that extends anteriorly between the fossae for the first mandibulary teeth. Purussourus mirandai sp. nov. was the largest predator in the swampy environments and represented the top trophic level in the Urumaco assemblage. A phylogenetic analysis of 164 characters in 68 ingroup crocodile taxa supported the association of P. neivensis and P. mirandai with five synapomorphies and confirmed the sister-group relationship of the genus with the Nettosuchidae.