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An ameghinornithid-like bird (Aves, Cariamae, ?Ameghinornithidae) from the early Oligocene of Egypt

Thomas A Stidham and N. Adam Smith

Plain Language Abstract

We describe a new avian fossil from ~33 million year old (Oligocene) deposits in northern Egypt. This new fossil is tentatively referred to Ameghinornithidae, an extinct group of potentially flightless birds with a geographic range that was restricted previously to Europe. The potential presence of Ameghinornithidae in Africa during the Oligocene suggests that this group of birds was more widely distributed geographically and may have survived longer than previously thought.

Resumen en Español

Un ave tipo ameghinornítido (Aves, Cariamae, ?Ameghinornithidae) del Oligoceno temprano de Egipto

Los Ameghinornithidae son un enigmático grupo de potenciales aves no voladoras del Paleógeno conocido actualmente por tres especies europeas. Se presenta un nuevo fósil que representa el primer registro de un ave de tipo ameghinornítido proveniente de África. El nuevo espécimen se halló en la Formación Jebel Qatrani del Oligoceno temprano, expuesta en la Depresión Fayum al norte de Egipto, el cual puede representar el registro más reciente del clado. El nuevo espécimen exhibe muchas similitudes con los ameghinornítidos europeos, entre ellas la falta de un puente supratendinoso osificado en el tibiotarso, un cóndilo lateral circular del tibiotarso, y un gran epicóndilo medial. El espécimen de Fayum es intermedio en tamaño en comparación con los Ameghinornithidae europeos y se caracteriza por la ausencia de una proyección del cóndilo medial del cráneo al cóndilo lateral y la presencia de crestas pareadas (y surcos asociados) proximales respecto al cóndilo lateral. La presencia de Ameghinornithidae en el Oligoceno temprano de África tendría implicaciones en relación a la edad y el patrón de los intercambios biogeográficos a través de la vía marítima del Tetis.

Palabras clave: evolución aviar; ave fósil; Formación Jebel Qatrani; Paleógeno; Strigogyps

Traducción: Enrique Peñalver

Résumé en Français

Un oiseau ressemblant à un ameghinornithide (Aves, Cariamae, ?Ameghinornithidae) provenant de l'Oligocène inférieur de l'Egypte

Ameghinornithidae est un groupe énigmatique d'oiseaux du Paléogène potentiellement non-volant, actuellement connus à partir de trois espèces européennes. Ici, nous rapportons un nouveau fossile qui représente le premier registre d'un oiseau ressemblant à un ameghinornithide en Afrique. Les nouveaux spécimens ont été recueillis dans la Formation Jebel Qatrani de l'Oligocène inférieur, exposée dans la dépression du Fayoum au nord de l'Egypte, et peuvent représenter le plus jeune registre de ce clade. Les nouveaux spécimens présentent de nombreuses similitudes avec les ameghinornithides européens, y compris l'absence d'un pont supratendinale ossifié sur le tibiotarse, un condyle latéral circulaire du tibiotarse, et un grand épitrochlée. Le spécimen du Fayum est de taille intermédiaire par rapport aux ameghinornithides européens et se caractérise par l'absence d'une saillie du condyle médial, crânien au condyle latéral et la présence de nervures appariées (et de rainures associées) à proximité du condyle latéral. L'apparition d'Ameghinornithidae durant l'Oligocène inférieur de l'Afrique aurait des implications concernant le timing et la structure des échanges biogéographiques dans la voie maritime Téthys.
Thomas A Stidham. Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, Chine.

Mots-clés: évolution aviaire; fossile d'oiseau; Formation Jebel Qatrani; Paléogène; Strigogyps

Translator: Kenny J. Travouillon

Deutsche Zusammenfassung

Ein ameghinornithiden-ähnlicher Vogel (Aves, Cariamae, ?Ameghinornithidae) aus dem frühen Oligozän von Ägypten

Die Ameghinornithidae sind eine rätselhafte Gruppe von möglicherweise flugunfähigen paläogenen Vögeln, die momentan mit drei europäischen Arten bekannt sind. Hier berichten wir über ein neues Fossil, das den ersten Nachweis eines ameghinornithiden-ähnlichen Vogels aus Afrika darstellt. Das neue Stück kommt aus der Jebel Qatrani Formation (frühes Oligozän), dort aus der Fayum Depression in Nordägypten und repräsentiert möglicherweise den jüngsten Nachweis dieser Klade. Das neue Stück weist viele Ähnlichkeiten mit europäischen Ameghinornithiden auf, einschließlich der fehlenden verknöcherten supratendinalen Brücke auf dem Tibiotarsus, eines runden lateralen Condylus auf dem Tibiotarsus und eines großen medialen Epicondylus. Das Fayum-Stück hat eine mittlere Größe im Vergleich mit den europäischen Ameghinornithiden und ist gekennzeichnet durch das Fehlen eines vorspringenden medialen Condylus cranial zum lateralen Condylus und durch das Vorhandensein von paarigen Graten (und assoziierte Rillen) proximal zum lateralen Condylus. Das Auftreten von Ameghinornithidae im frühen Oligozän von Afrika würde Folgen für die Zeitberechnung und das Muster des biogeografischen Austauschs über den Tethys-Seeweg haben.

Schlüsselwörter: Vogelevolution; fossiler Vogel; Jebel Qatrani Formation; Paläozän; Strigogyps

Translator: Eva Gebauer

Arabic

Translator: Ashraf M.T. Elewa

 

 

author1Thomas A Stidham
Key Laboratory of Vertebrate Evolution and Human Origins
Institute of Vertebrate Paleontology and Paleoanthropology
Chinese Academy of Sciences
Beijing 100044
China
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In 2012, Tom moved to Beijing to join the Institute of Vertebrate Paleontology and Paleoanthropology, and is now an associate professor there. He is an avian paleontologist and integrative biologist focused mostly on understanding Cenozoic bird evolution, and he also is interested in the role of past climate change and related biogeographic dispersal in the formation of current global avian diversity. In addition to working on bird-based (and other non-mammalian) projects across China (and Asia), he also travels around China hiking, birding, and experiencing the cultural and culinary diversity of Asia.

divider

author2N. Adam Smith
The Field Museum of Natural History
1400 South Lake Shore Drive
Chicago, Illinois 60605
USA
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and
North Carolina Museum of Natural Sciences
11 West Jones Street
Raleigh, North Carolina 2760
U.S.A.

Adam Smith is a postdoctoral fellow at the Field Museum in Chicago, Illinois, USA and a research affiliate at the North Carolina Museum of Natural Sciences. He was formerly a postdoctoral researcher at The National Evolutionary Synthesis Center on the campus of Duke University and has received degrees from Western Kentucky University (BS) and the University of Texas at Austin (PhD). He is a vertebrate paleontologist with broad interests in the evolution of birds with particular areas of focus including combined phylogenetic analyses, divergence time estimation and avian anatomy. More information can be found at: http://paleosmith.org. 

 

TABLE 1. Summary of Ameghinornithidae fossil remains. Note that the holotype specimen of Strigogyps dubius was destroyed (cited as "numéro 2" in the collection of the Bayerische Staatssammlung für Paläontologie und Historische Geologie, Munich; Gaillard, 1908, p.39).

Taxon Specimen # Material Locality Age Reference
Strigogyps dubius BSP-2 Distal tibiotarsus Quercy, France ?L. Eocene-
E. Oligocene
Gaillard, 1908
S. sapea SMF-ME 1818 Partial skeleton Messel, Germany Middle Eocene Peters, 1987
S. robustus GMH 5884, GMH 5883 Partial skeleton Geiseltal, Germany Middle Eocene Mayr, 2007
S. sp. SMF-ME 11094 Partial skeleton Messel, Germany Middle Eocene Mayr, 2005
Fayum sp. DPC 5659 Distal tibiotarsus Fayum, Egypt Early Oligocene This paper

 

TABLE 2. Size comparison of Ameghinornithidae tibiotarsi (in mm). Anatomical abbreviations: plT, preserved length of tibiotarsus; lwT, lateromedial width of tibiotarsus; cdT, craniocaudal depth of tibiotarsus. Estimated measurements and measurements of preserved dimensions are denoted by "*" and measurements missing owing to damage are denoted by "-". Data from Strigogyps species were compiled from Lambrecht (1935), Peters (1987, 2007) and Mayr (2005, 2007). Measurements of S. dubius are from a cast of the holotype specimen (PQ 1073) curated in the collection of the Musée Guimet d'Histoire Naturelle de Lyon (France) and provided by Peters (2007).

Taxon Specimen # plT lwT cdT
Strigogyps dubius BSP-2 21.5* 20.2 19.0
Strigogyps sapea SMF-ME 1818 150.0* 15.0* 14.0
Strigogyps robustus GMH 5884 196.0* 26.0 -
Fayum sp. DPC 5659 21.0* 17.1 15.1
 

FIGURE 1. Maps showing the geographic range of fossil localities with ameghinornithid specimens (left panel; 1, Quercy, France; 2, Messel, Germany; 3, Geiseltal, Germany; 4, Fayum Depression, Egypt) and the location of the Fayum Depression in northern Egypt (right panel) where the ameghinornithid-like specimen was collected.

figure1 

FIGURE 2. The distal tibiotarsus of the Fayum ameghinornithid-like bird (DPC 5659). 1, Lateral view. 2, Cranial view. 3, Medial view. 4, Caudal view. 5 , Distal view. Abbreviations : ep, elongate pit; es, extensor sulcus; fs, flattened spot; g, groove; is, intercondylar sulcus; lc , lateral condyle; mc, medial condyle; me, medial epicondyle; mf, medial flange of the tibial cartilage articulation; r, ridge; s, sand/sediment grains.

 figure2