New Material of Paleocene-Eocene Pellornis (Aves: Gruiformes) Clarifies the Pattern and Timing of the Extant Gruiform Radiation
New Material of Paleocene-Eocene Pellornis (Aves: Gruiformes) Clarifies the Pattern and Timing of the Extant Gruiform Radiation
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DOI：
10.3390/d11070102
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发表时间：
2019-06
期刊：
影响因子：
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通讯作者：
Grace M. Musser;D. Ksepka;D. Field
中科院分区：
文献类型：
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作者：
Grace M. Musser;D. Ksepka;D. Field
Pellornis mikkelseni是产于丹麦古新世晚期-始新世早期毛皮组的早期类化石。它大约有5400万年的历史，是鹤形目最早的明确记录之一。正模标本，也是迄今为止唯一被确认的标本，最初被认为是由部分颅后骨骼组成。然而，对包含正模标本的结节进行额外的机械准备后发现，该骨骼几乎是完整的，包括一个保存完好的头骨。除了从正模标本中提取新的信息外，我们还鉴定并描述了另外两个P. mikkelseni的标本，这些标本揭示了骨骼的进一步形态细节。这些标本共同显示，P. mikkelseni拥有一个鼻状头骨，并与着名的古近纪Messelornithidae（“Messel rails”）共享许多特征。为了重新评估P. mikkelseni的系统发育位置，我们修改了现有的形态数据集，增加了20个字符，4个现存的gruiform类群，6个灭绝的gruiform类群，以及基于正模标本和参考标本的新评分。系统发育分析恢复了包含P. mikkelseni、Messelornis、Songzia和冠蜥总科的进化枝，支持P. mikkelseni为冠蜥形。米克尔森氏白鲑的系统发育位置表明，最近的一些分歧时间分析低估了冠鹤形目的年龄。我们的研究结果表明，这一重要的分支古新世的起源，支持证据的快速早期辐射的新鸟类白垩纪末大规模灭绝。
Pellornis mikkelseni is an early gruiform from the latest Paleocene-earliest Eocene Fur Formation of Denmark. At approximately 54 million years old, it is among the earliest clear records of the Gruiformes. The holotype specimen, and only material thus far recognised, was originally considered to comprise a partial postcranial skeleton. However, additional mechanical preparation of the nodule containing the holotype revealed that the skeleton is nearly complete and includes a well-preserved skull. In addition to extracting new information from the holotype, we identify and describe two additional specimens of P. mikkelseni which reveal further morphological details of the skeleton. Together, these specimens show that P. mikkelseni possessed a schizorhinal skull and shared many features with the well-known Paleogene Messelornithidae (“Messel rails”). To reassess the phylogenetic position of P. mikkelseni, we modified an existing morphological dataset by adding 20 characters, four extant gruiform taxa, six extinct gruiform taxa, and novel scorings based on the holotype and referred specimens. Phylogenetic analyses recover a clade containing P. mikkelseni, Messelornis, Songzia and crown Ralloidea, supporting P. mikkelseni as a crown gruiform. The phylogenetic position of P. mikkelseni illustrates that some recent divergence time analyses have underestimated the age of crown Gruiformes. Our results suggest a Paleocene origin for this important clade, bolstering evidence for a rapid early radiation of Neoaves following the end-Cretaceous mass extinction.