The rhamphotheca of the Eocene pseudo-toothed birds from Antarctica

The Pelagornithidae are an extinct group of soaring birds that lived all over the world between the early Palaeocene and the Pliocene-Pleistocene and are characterised by the presence of hollow denticles along the tomial edges formed by the expansion of the premaxillary, maxillary, and dentary bones...

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Bibliographic Details
Published in:Historical biology 2024-09, Vol.36 (9), p.1745-1753
Main Authors: Piro, Alejandra, Acosta Hospitaleche, Carolina
Format: Article
Language:English
Subjects:
Antarctic Peninsula
beak morphology
Birds
Bones
Eocene
James Ross Basin
Paleocene
Paleogene
Pelagornithidae
Pleistocene
Pliocene
Rostrum
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Summary:The Pelagornithidae are an extinct group of soaring birds that lived all over the world between the early Palaeocene and the Pliocene-Pleistocene and are characterised by the presence of hollow denticles along the tomial edges formed by the expansion of the premaxillary, maxillary, and dentary bones. The presence of distinctive sulci in the upper and lower jaws together with the absence of wearing signs on the denticles, attributable to the handling of the prey, indicates the development of a resistant and compound rhamphotheca. To reconstruct it, we turned to the evidence provided by extant representatives with similar configurations and the osteological correlates of the beak. As a result, we propose a model for the middle-latest Eocene Antarctic Pelagornithidae, in which the rhamphotheca would have been formed by thick horny plates. The culminicorn was separated from the laternicorn by an extense sulcus nasi that continuous caudally to the apertura nasi ossea, a sturdy and hooked unguis maxillaris covering the rostrum, with small nares opening at the cranial end of the apertura nasi ossea, dorsal and ventral ramicorns, and a thick unguis mandibularis with a pseudomental fold and a sulcus on the mandible.
ISSN:0891-2963
1029-2381
DOI:10.1080/08912963.2023.2230584