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A tiny ornithodiran archosaur from the Triassic of Madagascar and the role of miniaturization in dinosaur and pterosaur ancestry.
Proc Natl Acad Sci U S A. 2020 07 28; 117(30):17932-17936.PN

Abstract

Early members of the dinosaur-pterosaur clade Ornithodira are very rare in the fossil record, obscuring our understanding of the origins of this important group. Here, we describe an early ornithodiran (Kongonaphon kely gen. et sp. nov.) from the Mid-to-Upper Triassic of Madagascar that represents one of the smallest nonavian ornithodirans. Although dinosaurs and gigantism are practically synonymous, an analysis of body size evolution in dinosaurs and other archosaurs in the context of this taxon and related forms demonstrates that the earliest-diverging members of the group may have been smaller than previously thought, and that a profound miniaturization event occurred near the base of the avian stem lineage. In phylogenetic analysis, Kongonaphon is recovered as a member of the Triassic ornithodiran clade Lagerpetidae, expanding the range of this group into Africa and providing data on the craniodental morphology of lagerpetids. The conical teeth of Kongonaphon exhibit pitted microwear consistent with a diet of hard-shelled insects, indicating a shift in trophic ecology to insectivory associated with diminutive body size. Small ancestral body size suggests that the extreme rarity of early ornithodirans in the fossil record owes more to taphonomic artifact than true reflection of the group's evolutionary history.

Authors+Show Affiliations

Paleontology Unit, North Carolina Museum of Natural Sciences, Raleigh, NC 27601; christian.kammerer@naturalsciences.org.Department of Geosciences, Virginia Tech, Blacksburg, VA 24060.Division of Paleontology, American Museum of Natural History, New York, NY 10024. Richard Gilder Graduate School, American Museum of Natural History, New York, NY 10024.Département de Paléontologie et d'Anthropologie Biologique, Université d'Antananarivo, Antananarivo 101, Madagascar.Department of Earth Science, University of California, Santa Barbara, CA 93106.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

32631980

Citation

Kammerer, Christian F., et al. "A Tiny Ornithodiran Archosaur From the Triassic of Madagascar and the Role of Miniaturization in Dinosaur and Pterosaur Ancestry." Proceedings of the National Academy of Sciences of the United States of America, vol. 117, no. 30, 2020, pp. 17932-17936.
Kammerer CF, Nesbitt SJ, Flynn JJ, et al. A tiny ornithodiran archosaur from the Triassic of Madagascar and the role of miniaturization in dinosaur and pterosaur ancestry. Proc Natl Acad Sci U S A. 2020;117(30):17932-17936.
Kammerer, C. F., Nesbitt, S. J., Flynn, J. J., Ranivoharimanana, L., & Wyss, A. R. (2020). A tiny ornithodiran archosaur from the Triassic of Madagascar and the role of miniaturization in dinosaur and pterosaur ancestry. Proceedings of the National Academy of Sciences of the United States of America, 117(30), 17932-17936. https://doi.org/10.1073/pnas.1916631117
Kammerer CF, et al. A Tiny Ornithodiran Archosaur From the Triassic of Madagascar and the Role of Miniaturization in Dinosaur and Pterosaur Ancestry. Proc Natl Acad Sci U S A. 2020 07 28;117(30):17932-17936. PubMed PMID: 32631980.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - A tiny ornithodiran archosaur from the Triassic of Madagascar and the role of miniaturization in dinosaur and pterosaur ancestry. AU - Kammerer,Christian F, AU - Nesbitt,Sterling J, AU - Flynn,John J, AU - Ranivoharimanana,Lovasoa, AU - Wyss,André R, Y1 - 2020/07/06/ PY - 2020/7/8/pubmed PY - 2020/9/18/medline PY - 2020/7/8/entrez KW - Dinosauria KW - Triassic KW - body size KW - evolution KW - phylogeny SP - 17932 EP - 17936 JF - Proceedings of the National Academy of Sciences of the United States of America JO - Proc Natl Acad Sci U S A VL - 117 IS - 30 N2 - Early members of the dinosaur-pterosaur clade Ornithodira are very rare in the fossil record, obscuring our understanding of the origins of this important group. Here, we describe an early ornithodiran (Kongonaphon kely gen. et sp. nov.) from the Mid-to-Upper Triassic of Madagascar that represents one of the smallest nonavian ornithodirans. Although dinosaurs and gigantism are practically synonymous, an analysis of body size evolution in dinosaurs and other archosaurs in the context of this taxon and related forms demonstrates that the earliest-diverging members of the group may have been smaller than previously thought, and that a profound miniaturization event occurred near the base of the avian stem lineage. In phylogenetic analysis, Kongonaphon is recovered as a member of the Triassic ornithodiran clade Lagerpetidae, expanding the range of this group into Africa and providing data on the craniodental morphology of lagerpetids. The conical teeth of Kongonaphon exhibit pitted microwear consistent with a diet of hard-shelled insects, indicating a shift in trophic ecology to insectivory associated with diminutive body size. Small ancestral body size suggests that the extreme rarity of early ornithodirans in the fossil record owes more to taphonomic artifact than true reflection of the group's evolutionary history. SN - 1091-6490 UR - https://www.unboundmedicine.com/medline/citation/32631980/A_tiny_ornithodiran_archosaur_from_the_Triassic_of_Madagascar_and_the_role_of_miniaturization_in_dinosaur_and_pterosaur_ancestry_ L2 - http://www.pnas.org/cgi/pmidlookup?view=long&pmid=32631980 DB - PRIME DP - Unbound Medicine ER -