Abstract

Remains of the stem anseriforms Presbyornithidae dominate among the avian material from the Tsagaan-Khushu locality in southern Mongolia (Naran-Bulak Formation; upper Paleocene–lower Eocene). Revision of the materials previously attributed to Presbyornis showed that they actually belong to two taxa of Presbyornithidae plus one or two taxa of stem Phoenicopterimorphae. The relatively large presbyornithid is morphologically similar to smaller specimens of Presbyornis pervetus Wetmore, 1926 from the lower Eocene of the United States. Another small form described here as Bumbalavis anatoides gen. et sp. nov. is morphologically more advanced than Presbyornis. Thus, the Mongolian materials do not confirm the presence of significant body size dimorphism in Presbyornis. Stem Phoenicopterimorphae from Tsagaan-Khushu are tentatively assigned to Juncitarsidae, to which the holotype of Presbyornis mongoliensis Kurochkin et Dyke, 2010 also belongs.

中文翻译：

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古新世-始新世蒙古长老鸟科（鸟类：鹅形目）的修订

摘要

在来自蒙古南部 Tsagaan-Khushu 地区（Naran-Bulak 组；上古新世 - 下始新世）的鸟类材料中，长角鸟科的残骸占主导地位。对先前归因于长老鸟的材料的修订表明，它们实际上属于长老鸟科的两个分类群加上一两个茎 Phoenicopterimorphae 的分类群。相对较大的长老鸟在形态上类似于1926 年来自美国始新世下游的长老鸟Wetmore 的较小标本。此处描述为Bumbalavis anatoides gen 的另一种小形式。等 sp. 十一月 在形态上比长老鸟更先进. 因此，蒙古材料并不能证实长老鸟存在明显的体型二态性。来自 Tsagaan-Khushu 的茎 Phoenicopterimorphae 暂时归属于 Juncitarsidae，Presbyornis mongoliensis Kurochkin et Dyke，2010的正模标本也属于它。