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Therrien F, Zelenitsky DK, Tanaka K, Voris JT, Erickson GM, Currie PJ, DeBuhr CL, Kobayashi Y. Exceptionally preserved stomach contents of a young tyrannosaurid reveal an ontogenetic dietary shift in an iconic extinct predator. Sci Adv 2023; 9:eadi0505. [PMID: 38064561 PMCID: PMC10846869 DOI: 10.1126/sciadv.adi0505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 10/31/2023] [Indexed: 12/18/2023]
Abstract
Tyrannosaurids were large carnivorous dinosaurs that underwent major changes in skull robusticity and body proportions as they grew, suggesting that they occupied different ecological niches during their life span. Although adults commonly fed on dinosaurian megaherbivores, the diet of juvenile tyrannosaurids is largely unknown. Here, we describe a remarkable specimen of a juvenile Gorgosaurus libratus that preserves the articulated hindlimbs of two yearling caenagnathid dinosaurs inside its abdominal cavity. The prey were selectively dismembered and consumed in two separate feeding events. This predator-prey association provides direct evidence of an ontogenetic dietary shift in tyrannosaurids. Juvenile individuals may have hunted small and young dinosaurs until they reached a size when, to satisfy energy requirements, they transitioned to feeding on dinosaurian megaherbivores. Tyrannosaurids occupied both mesopredator and apex predator roles during their life span, a factor that may have been key to their evolutionary success.
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Affiliation(s)
| | - Darla K. Zelenitsky
- Department of Earth, Energy, and Environment, University of Calgary, Calgary, Alberta, Canada
| | - Kohei Tanaka
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Jared T. Voris
- Department of Earth, Energy, and Environment, University of Calgary, Calgary, Alberta, Canada
| | - Gregory M. Erickson
- Department of Biological Science, Florida State University, Tallahassee, FL, USA
| | - Philip J. Currie
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Christopher L. DeBuhr
- Department of Earth, Energy, and Environment, University of Calgary, Calgary, Alberta, Canada
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2
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Tagliavento M, Davies AJ, Bernecker M, Staudigel PT, Dawson RR, Dietzel M, Götschl K, Guo W, Schulp AS, Therrien F, Zelenitsky DK, Gerdes A, Müller W, Fiebig J. Evidence for heterothermic endothermy and reptile-like eggshell mineralization in Troodon, a non-avian maniraptoran theropod. Proc Natl Acad Sci U S A 2023; 120:e2213987120. [PMID: 37011196 PMCID: PMC10104568 DOI: 10.1073/pnas.2213987120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 02/15/2023] [Indexed: 04/05/2023] Open
Abstract
The dinosaur-bird transition involved several anatomical, biomechanical, and physiological modifications of the theropod bauplan. Non-avian maniraptoran theropods, such as Troodon, are key to better understand changes in thermophysiology and reproduction occurring during this transition. Here, we applied dual clumped isotope (Δ47 and Δ48) thermometry, a technique that resolves mineralization temperature and other nonthermal information recorded in carbonates, to eggshells from Troodon, modern reptiles, and modern birds. Troodon eggshells show variable temperatures, namely 42 and 29 ± 2 °C, supporting the hypothesis of an endothermic thermophysiology with a heterothermic strategy for this extinct taxon. Dual clumped isotope data also reveal physiological differences in the reproductive systems between Troodon, reptiles, and birds. Troodon and modern reptiles mineralize their eggshells indistinguishable from dual clumped isotope equilibrium, while birds precipitate eggshells characterized by a positive disequilibrium offset in Δ48. Analyses of inorganic calcites suggest that the observed disequilibrium pattern in birds is linked to an amorphous calcium carbonate (ACC) precursor, a carbonate phase known to accelerate eggshell formation in birds. Lack of disequilibrium patterns in reptile and Troodon eggshells implies these vertebrates had not acquired the fast, ACC-based eggshell calcification process characteristic of birds. Observation that Troodon retained a slow reptile-like calcification suggests that it possessed two functional ovaries and was limited in the number of eggs it could produce; thus its large clutches would have been laid by several females. Dual clumped isotope analysis of eggshells of extinct vertebrates sheds light on physiological information otherwise inaccessible in the fossil record.
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Affiliation(s)
- Mattia Tagliavento
- Institute of Geosciences, Goethe University Frankfurt, Frankfurt am Main60438, Germany
| | - Amelia J. Davies
- Institute of Geosciences, Goethe University Frankfurt, Frankfurt am Main60438, Germany
| | - Miguel Bernecker
- Institute of Geosciences, Goethe University Frankfurt, Frankfurt am Main60438, Germany
| | - Philip T. Staudigel
- Institute of Geosciences, Goethe University Frankfurt, Frankfurt am Main60438, Germany
| | - Robin R. Dawson
- Department of Earth, Geographic and Climate Sciences, University of Massachusetts, Amherst, MA01003
| | - Martin Dietzel
- Institute of Applied Geosciences, Graz University of Technology,8010Graz, Austria
| | - Katja Götschl
- Institute of Applied Geosciences, Graz University of Technology,8010Graz, Austria
| | - Weifu Guo
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA02543
| | - Anne S. Schulp
- Vertebrate Evolution and Development, Naturalis Biodiversity Center,2333CRLeiden, the Netherlands
- Department of Earth Sciences, Faculty of Geosciences, Universiteit Utrecht,3584 CBUtrecht, the Netherlands
| | | | | | - Axel Gerdes
- Institute of Geosciences, Goethe University Frankfurt, Frankfurt am Main60438, Germany
- Frankfurt Isotope and Element Research Center, Institute of Geosciences, Goethe University Frankfurt, Frankfurt am Main60438, Germany
| | - Wolfgang Müller
- Institute of Geosciences, Goethe University Frankfurt, Frankfurt am Main60438, Germany
- Frankfurt Isotope and Element Research Center, Institute of Geosciences, Goethe University Frankfurt, Frankfurt am Main60438, Germany
| | - Jens Fiebig
- Institute of Geosciences, Goethe University Frankfurt, Frankfurt am Main60438, Germany
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3
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Norell MA, Wiemann J, Menéndez I, Fabbri M, Yu C, Marsicano CA, Moore-Nall A, Varricchio DJ, Pol D, Zelenitsky DK. Reply to: Triassic sauropodomorph eggshell might not be soft. Nature 2022; 610:E11-E14. [PMID: 36261552 DOI: 10.1038/s41586-022-05152-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Mark A Norell
- Division of Paleontology, American Museum of Natural History, New York, NY, USA
| | - Jasmina Wiemann
- Department of Earth and Planetary Sciences, Yale University, New Haven, CT, USA. .,Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA.
| | - Iris Menéndez
- Departamento de Geodinámica, Estratigrafía y Paleontología, Facultad de Ciencias Geológicas, Universidad Complutense de Madrid, Madrid, Spain. .,Departamento de Cambio Medioambiental, Instituto de Geociencias (UCM, CSIC), Madrid, Spain.
| | - Matteo Fabbri
- Department of Earth and Planetary Sciences, Yale University, New Haven, CT, USA. .,Negaunee Integrative Research Centre, Field Museum of Natural History, Chicago, IL, USA.
| | - Congyu Yu
- Division of Paleontology, American Museum of Natural History, New York, NY, USA
| | - Claudia A Marsicano
- Departamento de Ciencias Geológicas, Universidad de Buenos Aires, Buenos Aires, Argentina
| | | | | | - Diego Pol
- CONICET, Museo Paleontológico Egidio Feruglio, Trelew, Argentina
| | - Darla K Zelenitsky
- Department of Geoscience, University of Calgary, Calgary, Alberta, Canada
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4
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Xing L, Niu K, Ma W, Zelenitsky DK, Yang TR, Brusatte SL. An exquisitely preserved in-ovo theropod dinosaur embryo sheds light on avian-like prehatching postures. iScience 2022; 25:103516. [PMID: 35106456 PMCID: PMC8786642 DOI: 10.1016/j.isci.2021.103516] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 11/14/2021] [Accepted: 11/22/2021] [Indexed: 11/20/2022] Open
Abstract
Despite the discovery of many dinosaur eggs and nests over the past 100 years, articulated in-ovo embryos are remarkably rare. Here we report an exceptionally preserved, articulated oviraptorid embryo inside an elongatoolithid egg, from the Late Cretaceous Hekou Formation of southern China. The head lies ventral to the body, with the feet on either side, and the back curled along the blunt pole of the egg, in a posture previously unrecognized in a non-avian dinosaur, but reminiscent of a late-stage modern bird embryo. Comparison to other late-stage oviraptorid embryos suggests that prehatch oviraptorids developed avian-like postures late in incubation, which in modern birds are related to coordinated embryonic movements associated with tucking - a behavior controlled by the central nervous system, critical for hatching success. We propose that such pre-hatching behavior, previously considered unique to birds, may have originated among non-avian theropods, which can be further investigated with additional discoveries of embryo fossils.
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Affiliation(s)
- Lida Xing
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China
- School of the Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China
- Yingliang Stone Nature History Museum, Nan'an 362300, China
| | - Kecheng Niu
- Yingliang Stone Nature History Museum, Nan'an 362300, China
| | - Waisum Ma
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
| | | | - Tzu-Ruei Yang
- Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China
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5
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Tanaka K, Anvarov OUO, Zelenitsky DK, Ahmedshaev AS, Kobayashi Y. A new carcharodontosaurian theropod dinosaur occupies apex predator niche in the early Late Cretaceous of Uzbekistan. R Soc Open Sci 2021; 8:210923. [PMID: 34527277 PMCID: PMC8424376 DOI: 10.1098/rsos.210923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 08/23/2021] [Indexed: 06/13/2023]
Abstract
Carcharodontosauria is a group of medium to large-sized predatory theropods, distributed worldwide during the Cretaceous. These theropods were probably the apex predators of Asiamerica in the early Late Cretaceous prior to the ascent of tyrannosaurids, although few Laurasian species are known from this time due to a poor rock record. Here, we describe Ulughbegsaurus uzbekistanensis gen. et sp. nov. from the early Late Cretaceous (Turonian) of Central Asia, which represents the first record of a Late Cretaceous carcharodontosaurian from the region. This new taxon is represented by a large, isolated maxilla from the Bissekty Formation of the Kyzylkum Desert, the Republic of Uzbekistan, a formation yielding a rich and diverse assemblage of dinosaurs and other vertebrates from fragmentary remains. Comparison of the maxilla with that of other allosauroids indicates Ulughbegsaurus was 7.5-8 m in body length and greater than 1000 kg in body mass, suggesting it was the previously unrecognized apex predator of the Bissekty ecosystem while smaller known tryannosauroids and dromaeosaurids were probable mesopredators. The discovery of Ulughbegsaurus records the geologically latest stratigraphic co-occurrence of carcharodontosaurid and tyrannosauroid dinosaurs from Laurasia, and evidence indicates carcharodontosaurians remained the dominant predators relative to tyrannosauroids, at least in Asia, as late as the Turonian.
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Affiliation(s)
- Kohei Tanaka
- Life and Environmental Sciences, University of Tsukuba, Tsukuba 305-8572, Ibaraki, Japan
| | | | - Darla K. Zelenitsky
- Department of Geoscience, University of Calgary, Calgary, Alberta, Canada T2N 1N4
| | - Akhmadjon Shayakubovich Ahmedshaev
- State Geological Museum of the State Committee of the Republic of Uzbekistan on Geology and Mineral Resources, Tashkent 100060, Republic of Uzbekistan
| | - Yoshitsugu Kobayashi
- Hokkaido University Museum, Hokkaido University, Sapporo 060-0810, Hokkaido, Japan
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6
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Ke Y, Wu R, Zelenitsky DK, Brinkman D, Hu J, Zhang S, Jiang H, Han F. A large and unusually thick-shelled turtle egg with embryonic remains from the Upper Cretaceous of China. Proc Biol Sci 2021; 288:20211239. [PMID: 34403631 PMCID: PMC8370798 DOI: 10.1098/rspb.2021.1239] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 07/22/2021] [Indexed: 11/12/2022] Open
Abstract
Turtle eggs containing embryos are exceedingly rare in the fossil record. Here, we provide the first description and taxonomic identification, to our knowledge, of a fossilized embryonic turtle preserved in an egg, a fossil recovered from the Upper Cretaceous Xiaguan Formation of Henan Province, China. The specimen is attributed to the Nanhsiungchelyidae (Pan-Trionychia), an extinct group of large terrestrial turtles (possibly the species Yuchelys nanyangensis). The egg is rigid, spherical, and is one of the largest and thickest shelled Mesozoic turtle eggs known. Importantly, this specimen allowed identification of other nanhsiungchelyid egg clutches and comparison to those of Adocidae, as Nanhsiungchelyidae and Adocidae form the basal extinct clade Adocusia of the Pan-Trionychia (includes living soft-shelled turtles). Despite the differences in habitat adaptations, nanhsiungchelyids (terrestrial) and adocids (aquatic) shared several reproductive traits, including relatively thick eggshells, medium size clutches and relatively large eggs, which may be primitive for trionychoids (including Adocusia and Carrettochelyidae). The unusually thick calcareous eggshell of nanhsiungchelyids compared to those of all other turtles (including adocids) may be related to a nesting style adaptation to an extremely harsh environment.
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Affiliation(s)
- Yuzheng Ke
- School of Earth Science, China University of Geosciences (Wuhan), Wuhan 430074, People's Republic of China
| | - Rui Wu
- School of Earth Science, China University of Geosciences (Wuhan), Wuhan 430074, People's Republic of China
| | - Darla K. Zelenitsky
- Department of Geoscience, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Don Brinkman
- Royal Tyrrell Museum of Palaeontology, Box 7500, Drumheller, Alberta T0J 0Y0, Canada
| | - Jinfeng Hu
- School of Earth Science, China University of Geosciences (Wuhan), Wuhan 430074, People's Republic of China
| | - Shukang Zhang
- Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, People's Republic of China
| | - Haishui Jiang
- School of Earth Science, China University of Geosciences (Wuhan), Wuhan 430074, People's Republic of China
| | - Fenglu Han
- School of Earth Science, China University of Geosciences (Wuhan), Wuhan 430074, People's Republic of China
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7
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Dawson RR, Field DJ, Hull PM, Zelenitsky DK, Therrien F, Affek HP. Eggshell geochemistry reveals ancestral metabolic thermoregulation in Dinosauria. Sci Adv 2020; 6:eaax9361. [PMID: 32110726 PMCID: PMC7021498 DOI: 10.1126/sciadv.aax9361] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 12/13/2019] [Indexed: 06/10/2023]
Abstract
Studying the origin of avian thermoregulation is complicated by a lack of reliable methods for measuring body temperatures in extinct dinosaurs. Evidence from bone histology and stableisotopes often relies on uncertain assumptions about the relationship between growth rate and body temperature, or the isotopic composition (δ18O) of body water. Clumped isotope (Δ47) paleothermometry, based on binding of 13C to 18O, provides a more robust tool, but has yet to be applied across a broad phylogenetic range of dinosaurs while accounting for paleoenvironmental conditions. Applying this method to well-preserved fossil eggshells demonstrates that the three major clades of dinosaurs, Ornithischia, Sauropodomorpha, and Theropoda, were characterized by warm body temperatures. Dwarf titanosaurs may have exhibited similar body temperatures to larger sauropods, although this conclusion isprovisional, given current uncertainties in taxonomic assignment of dwarf titanosaur eggshell. Our results nevertheless reveal that metabolically controlled thermoregulation was the ancestral condition for Dinosauria.
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Affiliation(s)
- Robin R. Dawson
- Department of Geology and Geophysics, Yale University, New Haven, CT 06511, USA
| | - Daniel J. Field
- Department of Geology and Geophysics, Yale University, New Haven, CT 06511, USA
- Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, UK
| | - Pincelli M. Hull
- Department of Geology and Geophysics, Yale University, New Haven, CT 06511, USA
| | - Darla K. Zelenitsky
- Department of Geoscience, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - François Therrien
- Royal Tyrrell Museum of Palaeontology, Drumheller, Alberta T0J 0Y0, Canada
| | - Hagit P. Affek
- Department of Geology and Geophysics, Yale University, New Haven, CT 06511, USA
- Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
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8
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Tanaka K, Zelenitsky DK, Lü J, DeBuhr CL, Yi L, Jia S, Ding F, Xia M, Liu D, Shen C, Chen R. Incubation behaviours of oviraptorosaur dinosaurs in relation to body size. Biol Lett 2019; 14:rsbl.2018.0135. [PMID: 29769301 DOI: 10.1098/rsbl.2018.0135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 04/23/2018] [Indexed: 11/12/2022] Open
Abstract
Most birds sit on their eggs during incubation, a behaviour that likely evolved among non-avian dinosaurs. Several 'brooding' specimens of smaller species of oviraptorosaurs and troodontids reveal these non-avian theropods sat on their eggs, although little is known of incubation behaviour in larger theropod species. Here we examine egg clutches over a large body size range of oviraptorosaurs in order to understand the potential effect of body size on incubation behaviour. Eggshell porosity indicates that the eggs of all oviraptorosaurs were exposed in the nest, similar to brooding birds. Although all oviraptorosaur clutches consist of radially arranged eggs in a ring configuration, clutch morphology varies in that the central opening is small or absent in the smallest species, becomes significantly larger in larger species, and occupies most of the nest area in giant species. Our results suggest that the smallest oviraptorosaurs probably sat directly on the eggs, whereas with increasing body size more weight was likely carried by the central opening, reducing or eliminating the load on the eggs and still potentially allowing for some contact during incubation in giant species. This adaptation, not seen in birds, appears to remove the body size constraints of incubation behaviour in giant oviraptorosaurs.
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Affiliation(s)
- Kohei Tanaka
- Japan Society for the Promotion of Science, Nagoya University Museum, Furocho, Chikusa-Ku, Nagoya, Aichi 464-8601, Japan
| | - Darla K Zelenitsky
- Department of Geoscience, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Junchang Lü
- Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, People's Republic of China
| | - Christopher L DeBuhr
- Department of Geoscience, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Laiping Yi
- Ganzhou Museum, Ganzhou, Jiangxi 341000, People's Republic of China
| | - Songhai Jia
- Henan Geological Museum, Zhengzhou, Henan 450016, People's Republic of China
| | - Fang Ding
- Henan Geological Museum, Zhengzhou, Henan 450016, People's Republic of China
| | - Mengli Xia
- Henan Geological Museum, Zhengzhou, Henan 450016, People's Republic of China
| | - Di Liu
- Henan Geological Museum, Zhengzhou, Henan 450016, People's Republic of China
| | - Caizhi Shen
- Dalian Natural History Museum, Dalian, Liaoning 116000, People's Republic of China
| | - Rongjun Chen
- Dongyang Museum, Dongyang, Zhejiang 322100, People's Republic of China
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9
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Murray AM, Zelenitsky DK, Brinkman DB, Neuman AG. Two new Palaeocene osteoglossomorphs from Canada, with a reassessment of the relationships of the genus †Joffrichthys, and analysis of diversity from articulated versus microfossil material. Zool J Linn Soc 2018. [DOI: 10.1093/zoolinnean/zlx100] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Alison M Murray
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Darla K Zelenitsky
- Department of Geoscience, University of Calgary, Calgary, Alberta, Canada
| | | | - Andrew G Neuman
- Royal Tyrrell Museum of Palaeontology, Drumheller, Alberta, Canada
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10
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Erickson GM, Zelenitsky DK, Kay DI, Norell MA. Dinosaur incubation periods directly determined from growth-line counts in embryonic teeth show reptilian-grade development. Proc Natl Acad Sci U S A 2017; 114:540-545. [PMID: 28049837 PMCID: PMC5255600 DOI: 10.1073/pnas.1613716114] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Birds stand out from other egg-laying amniotes by producing relatively small numbers of large eggs with very short incubation periods (average 11-85 d). This aspect promotes high survivorship by limiting exposure to predation and environmental perturbation, allows for larger more fit young, and facilitates rapid attainment of adult size. Birds are living dinosaurs; their rapid development has been considered to reflect the primitive dinosaurian condition. Here, nonavian dinosaurian incubation periods in both small and large ornithischian taxa are empirically determined through growth-line counts in embryonic teeth. Our results show unexpectedly slow incubation (2.8 and 5.8 mo) like those of outgroup reptiles. Developmental and physiological constraints would have rendered tooth formation and incubation inherently slow in other dinosaur lineages and basal birds. The capacity to determine incubation periods in extinct egg-laying amniotes has implications for dinosaurian embryology, life history strategies, and survivorship across the Cretaceous-Paleogene mass extinction event.
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Affiliation(s)
- Gregory M Erickson
- Department of Biological Science, Florida State University, Tallahassee, FL 32306-4295;
| | - Darla K Zelenitsky
- Department of Geoscience, University of Calgary, Calgary, AB, Canada T2N 1N4
| | - David Ian Kay
- Department of Biological Science, Florida State University, Tallahassee, FL 32306-4295
| | - Mark A Norell
- Division of Paleontology, American Museum of Natural History, New York, NY 10024
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11
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Therrien F, Quinney A, Tanaka K, Zelenitsky DK. Accuracy of mandibular force profiles for bite force estimation and feeding behavior reconstruction in extant and extinct carnivorans. J Exp Biol 2016; 219:3738-3749. [DOI: 10.1242/jeb.143339] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 09/08/2016] [Indexed: 11/20/2022]
Abstract
Mandibular force profiles apply the principles of beam theory to identify mandibular biomechanical properties that reflect the bite force and feeding strategies of extant and extinct predators. While this method uses external dimensions of the mandibular corpus to determine its biomechanical properties, more accurate results could potentially be obtained by quantifying its internal cortical bone distribution. To test this possibility, mandibular force profiles were calculated using both external mandibular dimensions (‘solid mandible model’) and quantification of internal bone distribution of the mandibular corpus obtained from CT scans (‘hollow mandible model’) for five carnivorans (Canis lupus, Crocuta crocuta, Panthera leo, Neofelis nebulosa, and the extinct Canis dirus). Comparison reveals that the solid model slightly overestimates mandibular biomechanical properties, but the pattern of change in biomechanical properties along the mandible remains the same. As such, feeding behavior reconstructions are consistent between the two models and are not improved by computed tomography. Bite force estimates produced by the two models are similar, except for Crocuta where the solid model underestimates bite force by 10%-14%. This discrepancy is due to the more solid nature of the Crocuta mandible relative to other carnivorans. Therefore, computed tomography improves bite force estimation accuracy for taxa with thicker mandibular corpora, but not significantly so otherwise. Bite force estimates derived from mandibular force profiles are far closer to empirically-measured bite force than those inferred from jaw musculature dimension. Consequently, bite force estimates derived from this method can be used to calibrate finite-element analysis models.
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Affiliation(s)
- François Therrien
- Royal Tyrrell Museum of Palaeontology, PO Box 7500, Drumheller, AB, T0J 0Y0, Canada
- Department of Geoscience, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada
| | - Annie Quinney
- Arctic Institute of North America, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada
| | - Kohei Tanaka
- Department of Geoscience, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada
| | - Darla K. Zelenitsky
- Department of Geoscience, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada
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12
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Abstract
Knowledge about the types of nests built by dinosaurs can provide insight into the evolution of nesting and reproductive behaviors among archosaurs. However, the low preservation potential of their nesting materials and nesting structures means that most information can only be gleaned indirectly through comparison with extant archosaurs. Two general nest types are recognized among living archosaurs: 1) covered nests, in which eggs are incubated while fully covered by nesting material (as in crocodylians and megapodes), and 2) open nests, in which eggs are exposed in the nest and brooded (as in most birds). Previously, dinosaur nest types had been inferred by estimating the water vapor conductance (i.e., diffusive capacity) of their eggs, based on the premise that high conductance corresponds to covered nests and low conductance to open nests. However, a lack of statistical rigor and inconsistencies in this method render its application problematic and its validity questionable. As an alternative we propose a statistically rigorous approach to infer nest type based on large datasets of eggshell porosity and egg mass compiled for over 120 extant archosaur species and 29 archosaur extinct taxa/ootaxa. The presence of a strong correlation between eggshell porosity and nest type among extant archosaurs indicates that eggshell porosity can be used as a proxy for nest type, and thus discriminant analyses can help predict nest type in extinct taxa. Our results suggest that: 1) covered nests are likely the primitive condition for dinosaurs (and probably archosaurs), and 2) open nests first evolved among non-avian theropods more derived than Lourinhanosaurus and were likely widespread in non-avian maniraptorans, well before the appearance of birds. Although taphonomic evidence suggests that basal open nesters (i.e., oviraptorosaurs and troodontids) were potentially the first dinosaurs to brood their clutches, they still partially buried their eggs in sediment. Open nests with fully exposed eggs only became widespread among Euornithes. A potential co-evolution of open nests and brooding behavior among maniraptorans may have freed theropods from the ground-based restrictions inherent to covered nests and allowed the exploitation of alternate nesting locations. These changes in nesting styles and behaviors thus may have played a role in the evolutionary success of maniraptorans (including birds).
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Affiliation(s)
- Kohei Tanaka
- Department of Geoscience, University of Calgary, Calgary, Alberta, Canada
- * E-mail:
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13
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Quinney A, Mays C, Stilwell JD, Zelenitsky DK, Therrien F. The range of bioinclusions and pseudoinclusions preserved in a new Turonian (~90 ma) amber occurrence from Southern Australia. PLoS One 2015; 10:e0121307. [PMID: 25970501 PMCID: PMC4430482 DOI: 10.1371/journal.pone.0121307] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 01/29/2015] [Indexed: 11/19/2022] Open
Abstract
A new Turonian amber occurrence, representing the oldest in situ amber locality in Australia and the southern-most locality in Gondwana, has recently been discovered in the Otway Basin of Victoria. The amber was collected from petroleum cores and many pieces contain a range of inclusions that can provide information on the depositional history of the resin. To date, one species of fern spore (Cyathidites minor) and one species of lycophyte spore (Kraeuselisporites sp?) have been conclusively identified in the amber, along with filamentous microorganisms and degraded plant matter. Several samples are also rife with pseudoinclusions as reported recently in other ambers. The abundance of preserved particulate debris and wind dispersed spores suggest that the Otway amber formed subaerially. Furthermore, based on the range of bioinclusions and forms of pseudoinclusions preserved within a single piece of amber, the locus of hardening for individual samples is variably interpreted as occurring in the tree tops, on the tree trunk or on the ground surface. Notably, specific inclusion assemblages are associated with certain colours of amber. By extension, and in accordance with recent studies, amber colour may be indicative of depositional environment. Variation in the environment of solidification may, therefore, be sufficient to account for the broad range of morphological characteristics preserved in a single amber deposit.
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Affiliation(s)
- Annie Quinney
- School of Earth, Atmosphere & Environment, Monash University, Clayton, Victoria 3800, Australia
| | - Chris Mays
- School of Earth, Atmosphere & Environment, Monash University, Clayton, Victoria 3800, Australia
| | - Jeffrey D. Stilwell
- School of Earth, Atmosphere & Environment, Monash University, Clayton, Victoria 3800, Australia
| | - Darla K. Zelenitsky
- Department of Geoscience, University of Calgary, Calgary, Alberta, T2N 1N4 Canada
| | - François Therrien
- Royal Tyrrell Museum of Palaeontology, Drumheller, Alberta, T0J 0Y0 Canada
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Zelenitsky DK, Therrien F, Erickson GM, DeBuhr CL, Kobayashi Y, Eberth DA, Hadfield F. Feathered Non-Avian Dinosaurs from North America Provide Insight into Wing Origins. Science 2012; 338:510-4. [DOI: 10.1126/science.1225376] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Darla K. Zelenitsky
- Department of Geoscience, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - François Therrien
- Royal Tyrrell Museum of Palaeontology, Drumheller, Alberta TOJ OYO, Canada
| | - Gregory M. Erickson
- Department of Biological Science, Florida State University, Tallahassee, FL 32306–4295, USA
| | | | - Yoshitsugu Kobayashi
- Hokkaido University Museum, Hokkaido University, Sapporo, Hokkaido 060 0810, Japan
| | - David A. Eberth
- Royal Tyrrell Museum of Palaeontology, Drumheller, Alberta TOJ OYO, Canada
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Abstract
Little is known about the olfactory capabilities of extinct basal (non-neornithine) birds or the evolutionary changes in olfaction that occurred from non-avian theropods through modern birds. Although modern birds are known to have diverse olfactory capabilities, olfaction is generally considered to have declined during avian evolution as visual and vestibular sensory enhancements occurred in association with flight. To test the hypothesis that olfaction diminished through avian evolution, we assessed relative olfactory bulb size, here used as a neuroanatomical proxy for olfactory capabilities, in 157 species of non-avian theropods, fossil birds and living birds. We show that relative olfactory bulb size increased during non-avian maniraptoriform evolution, remained stable across the non-avian theropod/bird transition, and increased during basal bird and early neornithine evolution. From early neornithines through a major part of neornithine evolution, the relative size of the olfactory bulbs remained stable before decreasing in derived neoavian clades. Our results show that, rather than decreasing, the importance of olfaction actually increased during early bird evolution, representing a previously unrecognized sensory enhancement. The relatively larger olfactory bulbs of earliest neornithines, compared with those of basal birds, may have endowed neornithines with improved olfaction for more effective foraging or navigation skills, which in turn may have been a factor allowing them to survive the end-Cretaceous mass extinction.
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Affiliation(s)
- Darla K Zelenitsky
- Department of Geoscience, University of Calgary, Calgary, Alberta, Canada, T2N 1N4.
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Zelenitsky DK, Therrien F, Kobayashi Y. Olfactory acuity in theropods: palaeobiological and evolutionary implications. Proc Biol Sci 2009; 276:667-73. [PMID: 18957367 PMCID: PMC2660930 DOI: 10.1098/rspb.2008.1075] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2008] [Revised: 09/11/2008] [Accepted: 10/06/2008] [Indexed: 11/12/2022] Open
Abstract
This research presents the first quantitative evaluation of the olfactory acuity in extinct theropod dinosaurs. Olfactory ratios (i.e. the ratio of the greatest diameter of the olfactory bulb to the greatest diameter of the cerebral hemisphere) are analysed in order to infer the olfactory acuity and behavioural traits in theropods, as well as to identify phylogenetic trends in olfaction within Theropoda. A phylogenetically corrected regression of olfactory ratio to body mass reveals that, relative to predicted values, the olfactory bulbs of (i) tyrannosaurids and dromaeosaurids are significantly larger, (ii) ornithomimosaurs and oviraptorids are significantly smaller, and (iii) ceratosaurians, allosauroids, basal tyrannosauroids, troodontids and basal birds are within the 95% CI. Relative to other theropods, olfactory acuity was high in tyrannosaurids and dromaeosaurids and therefore olfaction would have played an important role in their ecology, possibly for activities in low-light conditions, locating food, or for navigation within large home ranges. Olfactory acuity was the lowest in ornithomimosaurs and oviraptorids, suggesting a reduced reliance on olfaction and perhaps an omnivorous diet in these theropods. Phylogenetic trends in olfaction among theropods reveal that olfactory acuity did not decrease in the ancestry of birds, as troodontids, dromaeosaurids and primitive birds possessed typical or high olfactory acuity. Thus, the sense of smell must have remained important in primitive birds and its presumed decrease associated with the increased importance of sight did not occur until later among more derived birds.
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Affiliation(s)
- Darla K Zelenitsky
- Department of Geoscience, University of Calgary, Calgary, Alberta, Canada T2N 1N4.
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Zelenitsky DK, Therrien FO, Joyce WG, Brinkman DB. First fossil gravid turtle provides insight into the evolution of reproductive traits in turtles. Biol Lett 2009; 4:715-8. [PMID: 18755656 DOI: 10.1098/rsbl.2008.0395] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Here we report on the first discovery of shelled eggs inside the body cavity of a fossil turtle and on an isolated egg clutch, both referable to the Cretaceous turtle Adocus. These discoveries provide a unique opportunity to gain insight into the reproductive traits of an extinct turtle and to understand the evolution of such traits among living turtles. The gravid adult and egg clutch indicate that Adocus laid large clutches of rigid-shelled spherical eggs and established their nests near rivers, traits that are shared by its closest living relatives, the soft-shelled turtles. Adocus eggshell, however, was probably more rigid than that of living turtles, based on its great thickness and structure, features that may represent unique adaptations to intense predation or to arid nest environments. In light of the reproductive traits observed in Adocus, the distribution of reproductive traits among turtles reveals that large clutches of rigid-shelled eggs are primitive for hidden-necked turtles (cryptodirans) and that spherical eggs may have evolved independently within this group.
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Affiliation(s)
- Darla K Zelenitsky
- Department of Geoscience, University of Calgary, Calgary, Alberta, Canada T2N 1N4.
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Abstract
An oviraptosaurian specimen (Dinosauria, Theropoda) from an Upper Cretaceous formation in China retains a pair of shelled eggs in the pelvis, providing direct evidence that oviraptorosaurian dinosaurs laid paired elongatoolithid eggs. The presence of the paired eggs suggests that theropod dinosaurs had two functional oviducts (like crocodiles) but that each oviduct produced only one egg at a time and that an entire egg clutch was laid through multiple ovipositions (like birds). The orientations of the eggs inside the skeleton and in clutches indicate that the mother came to the center of the nest to lay eggs.
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Affiliation(s)
- Tamaki Sato
- Canadian Museum of Nature (CMN), Post Office Box 3443, STN D, Ottawa, Ontario K1P 6P4, Canada.
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Abstract
A reappraisal of the eggshell of ratites clarifies aspects of its microstructure and ultrastructure. The phylogenetic usefulness of the eggshell data, consisting of discrete characters, is assessed using eggshell characters alone and by adding the eggshell characters to a data matrix from the literature based on skeletal characters. The resultant tree from the eggshell data alone yields Apteryx as the most basal ratite, dinornithids as the sister taxon of a clade of large living ratites, with Casuarius and Dromaius in a sister-group relationship. The combined eggshell and skeletal analysis revealed most groupings within Ratitae that were based on previous cladistic analysis of the skeletal characters alone, but also supports two equally parsimonious topologies: one identifies Dinornithidae and Apteryx as a clade at the base of Ratitae, and the other identifies Apteryx as the sister taxon of a clade consisting of all the other ratites. It is determined that the characteristics used to define the improperly named "ratite morphotype" in the current eggshell parataxonomy are not synapomorphies of the eggshell of Ratitae. An expanded cladistic analysis of the eggshells of avian and non-avian theropods is required to determine the phylogenetic usefulness of the characteristics of the ratite morphotype.
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