Last theropods of Europe from teeth from uppermost Maastrichtian of Spain (free pdf)

[Ben Creisler]

Ben Creisler

bcre...@gmail.com

A new paper:

Free pdf:

Oscar Castillo-Visa, Mattia Antonio Baiano, stephen l. Brusatte, Àngel Galobart & Bernat Vila (2025)
The last non-avian theropods of Europe: Palaeoecology and Biogeography inferred from dental records from the uppermost Maastrichtian of Catalonia, Spain
Cretaceous Research 106199
doi: https://doi.org/10.1016/j.cretres.2025.106199
https://www.sciencedirect.com/science/article/pii/S0195667125001223



Non-avian theropods were essential components of terrestrial ecosystems during the Mesozoic, were highly diverse in size and lifestyles across different regions of the planet. Here we assess the composition and diversity of the theropod fauna of the Ibero-Armorican island (the ancient region that encompassed present-day areas of Spain, Portugal, and France) during the final few hundred thousand years of the Cretaceous, by reviewing the theropod teeth assemblage from the locality of Molí del Baró-1 (upper Maastrichtian, C29r, Catalonia, Spain). Our study indicates a diverse fauna of small non-avian theropods with different feeding strategies and ecological niches. The tooth assemblage is significantly more diverse than previously thought and includes dental elements referred to dromaeosaurines, velociraptorines, troodontids, and an undetermined Dromaeosauridae tooth with similarities to microraptorines, as well as previously-referred teeth of cf. ?Richardoestesia and aff. Paronychodon. Microwear analysis reveals diverse feeding styles among these theropods, and particularly indicates that the troodontid had an omnivorous diet heavy in plant consumption. The assemblage of small-sized non-avian theropods and medium- to large-sized abelisaurids from the uppermost Maastrichtian of Ibero-Armorica differs from others from the European archipelago and worldwide, illustrating the high regional variability of theropod faunas around the time the asteroid impact ended the Cretaceous.

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[Vladimír Socha]

I wonder what "uppermost Maastrichtian" means in raw numbers here - 67 to 66 mya; 66.5 to 66.0 mya? Anyway, very interesting discovery.

Dne pátek 4. července 2025 v 5:12:32 UTC+2 uživatel Ben Creisler napsal:

[Thomas Richard Holtz]

The paper indicates that the deposits are within magnetic age C29r, which is the very last magnetic interval in the Maastrichtian (indeed, the impact occurs within C29r).

Based on recent calibration (https://pubs.geoscienceworld.org/gsa/gsabulletin/article-abstract/130/9-10/1615/530812/Calibration-of-chron-C29r-New-high-precision?redirectedFrom=fulltext), the base of c29r is dated to 66.371 +/- 0.162/0.067 Ma. Since these deposits predated the impact or extinction, they are within the last 300,000 years or so of the Maatrichtian.

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Thomas R. Holtz, Jr.
Email: tho...@umd.edu         Phone: 301-405-4084
Principal Lecturer, Vertebrate Paleontology

Office: CHEM 1225B, 8051 Regents Dr., College Park MD 20742

Dept. of Geology, University of Maryland
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[Vladimír Socha]

That's really interesting. And it's also another piece of still growing amount of evidence that non-avian dinosaur populations were doing still well right up to the K-Pg boundary. We now know "uppermost dinosaur faunas" from Canada, US, Bolivia, Uruguay(?), Antarctica(?), Morroco, Spain, France, Romania(?), India, China and some other countries.

In the Raton and Hell Creek Fm., the latest two dinosaur fossil finds are 37 cm (hadrosaurid footprints from Colorado) and 13 cm (Triceratops brow horn fragment from Montana) below the K-Pg. Based on an average rate of sedimentation (5 to 6 mm per 1000 years in Raton Fm. and 10 to 15 meters per 1 million years in Hell Creek Fm.) it would place these dinosaurs about 70 000 and 10 000 years (resp.) before the Chicxulub impactor arrival. And of course, then there's Tanis locality...

References:

Alvarez, L. W.; et al. (1980). Extraterrestrial cause for the Cretaceous–Tertiary extinction. Science. 208 (4448): 1095–1108.

During, M. A. D.; et al. (2022). The Mesozoic terminated in boreal spring. Nature. 603 (7899): 91–94.

Lyson, T. R.; et al. (2011). Dinosaurs extinction: Closing the ‘3 m gap’. Biology Letters. 7 (6): 925–928.

Bonsor, J. A.; et al. (2020). Dinosaur diversification rates were not in decline prior to the K-Pg boundary. Royal Society Open Science. 7 (11): 201195.

Sakamoto, M.; Benton, M. J.; Venditti, C. (2016). Dinosaurs in decline tens of millions of years before their final extinction. Proceedings of the National Academy of Sciences. 113 (18): 5036–5040.

Pillmore, C. L.; et al. (1994). Footprints in the rocks–new evidence from the Raton Basin that dinosaurs flourished on land until the terminal Cretaceous impact event. Papers Presented to New Developments the KT Event and Other Catastrophes in Earth History. LPI Contribution. 825: 89–90.

Orth, C. J.; et al. (1981). An Iridium Abundance Anomaly at the Palynological Cretaceous-Tertiary Boundary in Northern New Mexico. Science. 214 (4527): 1341–1343.

Lockley, M. G.; Hunt, A. P. (1994). A track of the giant theropod dinosaur Tyrannosaurus from close to the Cretaceous/Tertiary Boundary, northern New Mexico. Ichnos. 3 (3): 213–218.

DePalma, R. A.; et al. (2019). A seismically induced onshore surge deposit at the KPg boundary, North Dakota. Proceedings of the National Academy of Sciences. 116 (17): 8190–8199.

Renne, P. R.; et al. (2013). Time Scales of Critical Events Around the Cretaceous-Paleogene Boundary. Science. 339 (6120): 684–687.

Dne pondělí 7. července 2025 v 15:07:19 UTC+2 uživatel Thomas Richard Holtz napsal: