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Eocene birds of Mongolia (1 Viewer)

Fred Ruhe

Well-known member
Netherlands
Sarah C. Hood, Chris R. Torres, Mark A. Norell & Julia A. Clarke, 2019

New fossil birds from the earliest Eocene of Mongolia

American Museum novitates, no. 3934: 1-24

Abstract:

Understanding of the Asian early Paleogene avifauna is limited relative to that of North American and European avifauna of the same period. While major patterns of mammalian faunal exchange among these three regions across the Paleocene/Eocene boundary have been described, much less is known about the dynamics of bird diversity over the same time interval. Here, we report bird fossils from the earliest Eocene Bumban Member of the Naranbulag Formation in central Mongolia that add to the known record from Asia from just after this boundary. Most of this material, collected by the joint American Museum of Natural History/Mongolia Academy of Sciences expeditions, is referable to a previously described taxon in Presbyornithidae (Anseriformes). However, five isolated elements are identified as comprising at least four species from at least three other major avian clades. While further inclusive phylogenetic analyses of each of these clades are necessary, the new remains represent possible earliest occurrences in Asia of these clades. The material includes a humerus and a furcula from shorebirds (Pan-Charadriiformes), a quadrate from a stem member of the flamingo-grebe lineage (Pan-Mirandornithes), and a coracoid from a stem galliform (Pangalliformes). We also report a humerus with uncertain phylogenetic affinities but with similarities to core Gruiformes. These new fossils expand our knowledge of the Asian avifauna during this time and have the potential to further inform our understanding of the early biogeography of these clades. The shorebird and flamingo-grebe material indicate that both these lineages were present in Asia by the earliest Eocene. The pan-mirandornithine quadrate provides insight into the early feeding ecology of the flamingo-grebe clade.

Free pdf: http://digitallibrary.amnh.org/bitstream/handle/2246/6956/N3934.pdf?sequence=1&isAllowed=y

Enjoy,

Fred
 
SYSTEMATIC PALEONTOLOGY

PAN-CHARADRIIFORMES, new clade
Definition: “Pan-Charadriiformes” refers to the clade containing all birds more closely related to Charadrius hiaticula and Sterna hirundo than to flamingos and grebes (Mirandornithes) based on the Prum et al. (2015) reference phylogeny.

Gen. et sp. indet.
Referred Specimen: IGM 100/1435 (distal end of left humerus.
Measurements: Dorsoventral width of distal end, 4.7 mm.

Gen. et sp. indet.
Referred Specimen: IGM 100/1268 (furcula missing both omal extremities.
Measurements: Maximum preserved length of right ramus, 13.7 mm; maximum length of furcular apophysis, 3 mm; maximum preserved interclavicular width from lateral margins of rami, 7.5 mm.

PAN-MIRANDORNITHES, new clade
Definition: “Pan-Mirandornithes” refers to the clade including all birds more closely related to Phoenicopterus ruber and Podiceps cristatus than to shorebirds (Charadriiformes) based on the reference phylogeny in Prum et al. (2015).
Referred Taxa: In addition to crown-group Mirandornithes (flamingos and grebes), Pan-Mirandornithes also includes the proposed stem mirandornithine Juncitarsus (Olson and Feduccia, 1980; Mayr, 2014).

Gen. et sp. indet.
Referred Specimen: IGM 100/1418 (left quadrate lacking most of the orbital process).
Measurements: Lateromedial width of mandibular articulation, 6 mm; maximum dorsoventral height, 9.4 mm.

PAN-GALLIFORMES Clarke, 2002
cf. QUERCYMEGAPODIIDAE Mourer-Chauviré, 1992

Gen. et sp. indet.
Referred Specimen: IGM 100/1371 (omal end of left coracoid).
Measurements: Maximum length as preserved, 13.6 mm; maximum mediolateral width of omal end, 4.7 mm.

Aves, gen. et sp. indet.
Referred Specimen: IGM 100/1360 (distal end of left humerus).
Measurements: Dorsoventral width of distal end, 5 mm.

Fred
 
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