Lokiceratops rangiformis gen. et sp. nov. (Ceratopsidae: Centrosaurinae) from the Campanian Judith River Formation of Montana reveals rapid regional radiations and extreme endemism within centrosaurine dinosaurs

Mark A. Loewen, Joseph J.W. Sertich, Scott Sampson, Jingmai K. O'Connor, Savhannah Carpenter, Brock Sisson, Anna Øhlenschlæger, Andrew A. Farke, Peter J. Makovicky, Nick Longrich, David C. Evans

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2 Citations (SciVal)

Abstract

The Late Cretaceous of western North America supported diverse dinosaur assemblages, though understanding patterns of dinosaur diversity, evolution, and extinction has been historically limited by unequal geographic and temporal sampling. In particular, the existence and extent of faunal endemism along the eastern coastal plain of Laramidia continues to generate debate, and finer scale regional patterns remain elusive. Here, we report a new centrosaurine ceratopsid, Lokiceratops rangiformis, from the lower portion of the McClelland Ferry Member of the Judith River Formation in the Kennedy Coulee region along the Canada-USA border. Dinosaurs from the same small geographic region, and from nearby, stratigraphically equivalent horizons of the lower Oldman Formation in Canada, reveal unprecedented ceratopsid richness, with four sympatric centrosaurine taxa and one chasmosaurine taxon. Phylogenetic results show that Lokiceratops, together with Albertaceratops and Medusaceratops, was part of a clade restricted to a small portion of northern Laramidia approximately 78 million years ago. This group, Albertaceratopsini, was one of multiple centrosaurine clades to undergo geographically restricted radiations, with Nasutuceratopsini restricted to the south and Centrosaurini and Pachyrostra restricted to the north. High regional endemism in centrosaurs is associated with, and may have been driven by, high speciation rates and diversity, with competition between dinosaurs limiting their geographic range. High speciation rates may in turn have been driven in part by sexual selection or latitudinally uneven climatic and floral gradients. The high endemism seen in centrosaurines and other dinosaurs implies that dinosaur diversity is underestimated and contrasts with the large geographic ranges seen in most extant mammalian megafauna.

Original languageEnglish
Article numbere17224
JournalPeerJ
Volume12
Issue number6
DOIs
Publication statusPublished - 20 Jun 2024

Funding

The following grant information was disclosed by the authors: Evolutionsmuseet at Knuthenborg. National Science Foundation: 0819953. Natural History Museum of Utah. University of Utah. Natural Sciences and Engineering Research Council (NSERC) Discovery Grant and a Royal Ontario Museum Peer Review Grant. This research was financially supported by a research grant from the Evolutionsmuseet at Knuthenborg to Mark A. Loewen, Anna \u00D8hlenschl\u00E6ger, and Brock Sisson. Additional funding was provided by research grants from the National Science Foundation (NSF 0819953), Natural History Museum of Utah, and the University of Utah to Mark A. Loewen, Savhannah Carpenter, and Scott Sampson. David C. Evans was supported by a Natural Sciences and Engineering Research Council (NSERC) Discovery Grant and a Royal Ontario Museum Peer Review Grant. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

FundersFunder number
Royal Ontario Museum
University of Utah
Natural Sciences and Engineering Research Council of Canada
National Science Foundation0819953, NSF 0819953

    Keywords

    • Ceratopsia
    • Dinosauria
    • Frill
    • Laramidia

    ASJC Scopus subject areas

    • General Neuroscience
    • General Biochemistry,Genetics and Molecular Biology
    • General Agricultural and Biological Sciences

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