The Halcyornithidae from the early Eocene London Clay of Walton-on-the-Naze (Essex, UK): A species complex of Paleogene arboreal birds

IF 1.6 4区地球科学 Q2 PALEONTOLOGY

Geobios Pub Date : 2024-04-01 DOI:10.1016/j.geobios.2023.06.003

Gerald Mayr , Andrew C. Kitchener

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引用次数: 0

Abstract

We report fossils of the Halcyornithidae from the early Eocene London Clay of Walton-on-the-Naze (Essex, UK). The material includes remains of nine individuals of these small zygodactyl birds, which belong to at least seven different species, two of which are newly described. This documents a high species richness of halcyornithids in the London Clay, and these birds apparently underwent a significant radiation in the early Paleogene. One of the specimens includes a skull with a proportionally much smaller neurocranium than in Pseudasturides macrocephalus from Messel, suggesting an increased encephalization of halcyornithids towards the middle Eocene. A previously undescribed variation in sternum morphology of halcyornithids distinguishes the fossils we assign to the taxa Pulchrapollia and Cyrilavis and indicates that halcyornithids occupied disparate ecological niches. Furthermore, sternum morphology supports a sister group relationship between the halcyornithid taxa Pulchrapollia and Pseudasturides. The closest extant relatives of the Halcyornithidae remain elusive, but our new osteological data substantiate the hypothesis of a sister group relationship to the Messelasturidae, another group of Eocene birds with zygodactyl feet.

[http://zoobank.org/urn:lsid:zoobank.org:pub:DDC1768F-1389-4F36-92F6-46DA318A0C19].

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纳泽河畔沃尔顿始新世早期伦敦粘土中的Halcyornithidae（英国埃塞克斯郡）：古近纪树栖鸟类的一个物种复合体

我们报告了来自英国埃塞克斯郡沃尔顿-纳兹（Walton-the-Naze）早始新世伦敦粘土的 Halcyornithidae 化石。这些材料包括九只小型颧骨鸟的遗骸，它们至少属于七个不同的物种，其中两个是新描述的物种。这记录了伦敦粘土地区半齿鸟类物种的丰富性，这些鸟类在古近纪早期显然经历了一次重要的辐射。其中一个标本包括一个头骨，其神经颅骨的比例比梅塞尔（Messel）出土的大头盖骨（Pseudasturides macrocephalus）要小得多，这表明在始新世中期，半角鸟类的脑化程度有所提高。半棘蜥胸骨形态的变异是以前从未描述过的，这种变异将我们归入 Pulchrapollia 和 Cyrilavis 类群的化石区分开来，并表明半棘蜥占据着不同的生态位。此外，胸骨形态支持半角龙类分类群 Pulchrapollia 和 Pseudasturides 之间的姊妹群关系。半棘鸟科的现生近亲仍然难以捉摸，但我们新的骨学数据证实了与Messelasturidae（另一个具有双足的始新世鸟类类群）为姊妹类群关系的假说。[http://zoobank.org/urn:lsid:zoobank.org:pub:DDC1768F-1389-4F36-92F6-46DA318A0C19]。

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来源期刊

Geobios 地学-古生物学

CiteScore

3.30

自引率

6.20%

发文量

审稿时长

6-12 weeks

期刊介绍： Geobios publishes bimonthly in English original peer-reviewed articles of international interest in any area of paleontology, paleobiology, paleoecology, paleobiogeography, (bio)stratigraphy and biogeochemistry. All taxonomic groups are treated, including microfossils, invertebrates, plants, vertebrates and ichnofossils. Geobios welcomes descriptive papers based on original material (e.g. large Systematic Paleontology works), as well as more analytically and/or methodologically oriented papers, provided they offer strong and significant biochronological/biostratigraphical, paleobiogeographical, paleobiological and/or phylogenetic new insights and perspectices. A high priority level is given to synchronic and/or diachronic studies based on multi- or inter-disciplinary approaches mixing various fields of Earth and Life Sciences. Works based on extant data are also considered, provided they offer significant insights into geological-time studies.