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New giant carnivorous dinosaur reveals convergent evolutionary trends in theropod arm reduction.
Curr Biol. 2022 07 25; 32(14):3195-3202.e5.CB

Abstract

Giant carnivorous dinosaurs such as Tyrannosaurus rex and abelisaurids are characterized by highly reduced forelimbs that stand in contrast to their huge dimensions, massive skulls, and obligate bipedalism.1,2 Another group that follows this pattern, yet is still poorly known, is the Carcharodontosauridae: dominant predators that inhabited most continents during the Early Cretaceous3-5 and reached their largest sizes in Aptian-Cenomanian times.6-10 Despite many discoveries over the last three decades, aspects of their anatomy, especially with regard to the skull, forearm, and feet, remain poorly known. Here we report a new carcharodontosaurid, Meraxes gigas, gen. et sp. nov., based on a specimen recovered from the Upper Cretaceous Huincul Formation of northern Patagonia, Argentina. Phylogenetic analysis places Meraxes among derived Carcharodontosauridae, in a clade with other massive South American species. Meraxes preserves novel anatomical information for derived carcharodontosaurids, including an almost complete forelimb that provides evidence for convergent allometric trends in forelimb reduction among three lineages of large-bodied, megapredatory non-avian theropods, including a remarkable degree of parallelism between the latest-diverging tyrannosaurids and carcharodontosaurids. This trend, coupled with a likely lower bound on forelimb reduction, hypothesized to be about 0.4 forelimb/femur length, combined to produce this short-armed pattern in theropods. The almost complete cranium of Meraxes permits new estimates of skull length in Giganotosaurus, which is among the longest for theropods. Meraxes also provides further evidence that carchardontosaurids reached peak diversity shortly before their extinction with high rates of trait evolution in facial ornamentation possibly linked to a social signaling role.

Authors+Show Affiliations

CONICET, Buenos Aires, Argentina; Área Laboratorio e Investigación, Museo Municipal "Ernesto Bachmann," Villa El Chocón 8311, Neuquén, Argentina; Universidad Nacional de Río Negro (UNRN), Isidro Lobo 516, R8332 Gral. Roca, Río Negro, Argentina. Electronic address: jicanale@unrn.edu.ar.CONICET, Buenos Aires, Argentina; Área de Paleontología, Fundación de Historia Natural Félix de Azara, CCNAA, Universidad Maimónides, Hidalgo 775, 1405 Ciudad Autónoma de Buenos Aires, Argentina.CONICET, Buenos Aires, Argentina; Área de Paleontología, Fundación de Historia Natural Félix de Azara, CCNAA, Universidad Maimónides, Hidalgo 775, 1405 Ciudad Autónoma de Buenos Aires, Argentina.West Virginia University Institute of Technology, 410 Neville Street, Life Sciences 119, Beckley, WV 25801 USA.Dinosaur Institute, Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, CA 90007 USA.Ottawa-Carleton Geoscience Centre, Department of Earth Sciences, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada; Negaunee Integrative Research Center, The Field Museum of Natural History, 1400 S. DuSable Lake Shore Drive, Chicago, IL 60605, USA.Negaunee Integrative Research Center, The Field Museum of Natural History, 1400 S. DuSable Lake Shore Drive, Chicago, IL 60605, USA.Área Laboratorio e Investigación, Museo Municipal "Ernesto Bachmann," Villa El Chocón 8311, Neuquén, Argentina.CONICET, Buenos Aires, Argentina; Instituto Multidisciplinario de Investigaciones Biológicas de San Luis (IMIBIO-SL), CONICET-Universidad Nacional de San Luis. Área de Zoología, Facultad de Química, Bioquímica y Farmacia, UNSL. Ejército de los Andes 950, 5700 San Luis, Argentina.Negaunee Integrative Research Center, The Field Museum of Natural History, 1400 S. DuSable Lake Shore Drive, Chicago, IL 60605, USA; Department of Earth and Environmental Sciences, University of Minnesota - Twin Cities, 116 Church Street SE, Minneapolis, MN 55455 USA.

Pub Type(s)

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

Language

eng

PubMed ID

35803271

Citation

Canale, Juan I., et al. "New Giant Carnivorous Dinosaur Reveals Convergent Evolutionary Trends in Theropod Arm Reduction." Current Biology : CB, vol. 32, no. 14, 2022, pp. 3195-3202.e5.
Canale JI, Apesteguía S, Gallina PA, et al. New giant carnivorous dinosaur reveals convergent evolutionary trends in theropod arm reduction. Curr Biol. 2022;32(14):3195-3202.e5.
Canale, J. I., Apesteguía, S., Gallina, P. A., Mitchell, J., Smith, N. D., Cullen, T. M., Shinya, A., Haluza, A., Gianechini, F. A., & Makovicky, P. J. (2022). New giant carnivorous dinosaur reveals convergent evolutionary trends in theropod arm reduction. Current Biology : CB, 32(14), 3195-e5. https://doi.org/10.1016/j.cub.2022.05.057
Canale JI, et al. New Giant Carnivorous Dinosaur Reveals Convergent Evolutionary Trends in Theropod Arm Reduction. Curr Biol. 2022 07 25;32(14):3195-3202.e5. PubMed PMID: 35803271.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - New giant carnivorous dinosaur reveals convergent evolutionary trends in theropod arm reduction. AU - Canale,Juan I, AU - Apesteguía,Sebastián, AU - Gallina,Pablo A, AU - Mitchell,Jonathan, AU - Smith,Nathan D, AU - Cullen,Thomas M, AU - Shinya,Akiko, AU - Haluza,Alejandro, AU - Gianechini,Federico A, AU - Makovicky,Peter J, Y1 - 2022/07/07/ PY - 2022/02/10/received PY - 2022/04/08/revised PY - 2022/05/25/accepted PY - 2022/7/9/pubmed PY - 2022/7/29/medline PY - 2022/7/8/entrez KW - Carcharodontosauridae KW - Cretaceous KW - Dinosauria KW - Patagonia KW - Theropoda KW - anatomy KW - evolution SP - 3195 EP - 3202.e5 JF - Current biology : CB JO - Curr Biol VL - 32 IS - 14 N2 - Giant carnivorous dinosaurs such as Tyrannosaurus rex and abelisaurids are characterized by highly reduced forelimbs that stand in contrast to their huge dimensions, massive skulls, and obligate bipedalism.1,2 Another group that follows this pattern, yet is still poorly known, is the Carcharodontosauridae: dominant predators that inhabited most continents during the Early Cretaceous3-5 and reached their largest sizes in Aptian-Cenomanian times.6-10 Despite many discoveries over the last three decades, aspects of their anatomy, especially with regard to the skull, forearm, and feet, remain poorly known. Here we report a new carcharodontosaurid, Meraxes gigas, gen. et sp. nov., based on a specimen recovered from the Upper Cretaceous Huincul Formation of northern Patagonia, Argentina. Phylogenetic analysis places Meraxes among derived Carcharodontosauridae, in a clade with other massive South American species. Meraxes preserves novel anatomical information for derived carcharodontosaurids, including an almost complete forelimb that provides evidence for convergent allometric trends in forelimb reduction among three lineages of large-bodied, megapredatory non-avian theropods, including a remarkable degree of parallelism between the latest-diverging tyrannosaurids and carcharodontosaurids. This trend, coupled with a likely lower bound on forelimb reduction, hypothesized to be about 0.4 forelimb/femur length, combined to produce this short-armed pattern in theropods. The almost complete cranium of Meraxes permits new estimates of skull length in Giganotosaurus, which is among the longest for theropods. Meraxes also provides further evidence that carchardontosaurids reached peak diversity shortly before their extinction with high rates of trait evolution in facial ornamentation possibly linked to a social signaling role. SN - 1879-0445 UR - https://www.unboundmedicine.com/medline/citation/35803271/New_giant_carnivorous_dinosaur_reveals_convergent_evolutionary_trends_in_theropod_arm_reduction_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0960-9822(22)00860-0 DB - PRIME DP - Unbound Medicine ER -