1
|
Title PO, Singhal S, Grundler MC, Costa GC, Pyron RA, Colston TJ, Grundler MR, Prates I, Stepanova N, Jones MEH, Cavalcanti LBQ, Colli GR, Di-Poï N, Donnellan SC, Moritz C, Mesquita DO, Pianka ER, Smith SA, Vitt LJ, Rabosky DL. The macroevolutionary singularity of snakes. Science 2024; 383:918-923. [PMID: 38386744 DOI: 10.1126/science.adh2449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 01/02/2024] [Indexed: 02/24/2024]
Abstract
Snakes and lizards (Squamata) represent a third of terrestrial vertebrates and exhibit spectacular innovations in locomotion, feeding, and sensory processing. However, the evolutionary drivers of this radiation remain poorly known. We infer potential causes and ultimate consequences of squamate macroevolution by combining individual-based natural history observations (>60,000 animals) with a comprehensive time-calibrated phylogeny that we anchored with genomic data (5400 loci) from 1018 species. Due to shifts in the dynamics of speciation and phenotypic evolution, snakes have transformed the trophic structure of animal communities through the recurrent origin and diversification of specialized predatory strategies. Squamate biodiversity reflects a legacy of singular events that occurred during the early history of snakes and reveals the impact of historical contingency on vertebrate biodiversity.
Collapse
Affiliation(s)
- Pascal O Title
- Department of Ecology and Evolution, Stony Brook University, Stony Brook, NY 11794, USA
- Environmental Resilience Institute, Indiana University, Bloomington, IN 47408, USA
- Museum of Zoology and Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Sonal Singhal
- Museum of Zoology and Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Biology, California State University, Dominguez Hills, Carson, CA 90747, USA
| | - Michael C Grundler
- Museum of Zoology and Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Gabriel C Costa
- Museum of Zoology and Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Biology and Environmental Sciences, Auburn University at Montgomery, Montgomery, AL 36117, USA
| | - R Alexander Pyron
- Department of Biological Sciences, The George Washington University, Washington, DC 20052, USA
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, 20560, USA
| | - Timothy J Colston
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, 20560, USA
- Biology Department, University of Puerto Rico at Mayagüez, Mayagüez 00680, Puerto Rico
| | - Maggie R Grundler
- Museum of Zoology and Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, CA 94720, USA
- Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Ivan Prates
- Museum of Zoology and Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Natasha Stepanova
- Museum of Zoology and Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Marc E H Jones
- Science Group: Fossil Reptiles, Amphibians and Birds Section, Natural History Museum, London SW7 5BD, UK
- Research Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
- Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | - Lucas B Q Cavalcanti
- Departamento de Sistemática e Ecologia, Universidade Federal da Paraíba, João Pessoa, Paraíba 58051-900, Brazil
| | - Guarino R Colli
- Departamento de Zoologia, Universidade de Brasília, Brasília, Distrito Federal 70910-900, Brazil
| | - Nicolas Di-Poï
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, 00014 Helsinki, Finland
| | | | - Craig Moritz
- Research School of Biology, The Australian National University, Canberra, ACT 2600, Australia
| | - Daniel O Mesquita
- Departamento de Sistemática e Ecologia, Universidade Federal da Paraíba, João Pessoa, Paraíba 58051-900, Brazil
| | - Eric R Pianka
- Department of Integrative Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Stephen A Smith
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Laurie J Vitt
- Sam Noble Museum and Department of Biology, University of Oklahoma, Norman, OK, USA
| | - Daniel L Rabosky
- Museum of Zoology and Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| |
Collapse
|
2
|
Alarcón-Muñoz J, Vargas AO, Püschel HP, Soto-Acuña S, Manríquez L, Leppe M, Kaluza J, Milla V, Gutstein CS, Palma-Liberona J, Stinnesbeck W, Frey E, Pino JP, Bajor D, Núñez E, Ortiz H, Rubilar-Rogers D, Cruzado-Caballero P. Relict duck-billed dinosaurs survived into the last age of the dinosaurs in subantarctic Chile. SCIENCE ADVANCES 2023; 9:eadg2456. [PMID: 37327335 PMCID: PMC10275600 DOI: 10.1126/sciadv.adg2456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 05/11/2023] [Indexed: 06/18/2023]
Abstract
In the dusk of the Mesozoic, advanced duck-billed dinosaurs (Hadrosauridae) were so successful that they likely outcompeted other herbivores, contributing to declines in dinosaur diversity. From Laurasia, hadrosaurids dispersed widely, colonizing Africa, South America, and, allegedly, Antarctica. Here, we present the first species of a duck-billed dinosaur from a subantarctic region, Gonkoken nanoi, of early Maastrichtian age in Magallanes, Chile. Unlike duckbills further north in Patagonia, Gonkoken descends from North American forms diverging shortly before the origin of Hadrosauridae. However, at the time, non-hadrosaurids in North America had become replaced by hadrosaurids. We propose that the ancestors of Gonkoken arrived earlier in South America and reached further south, into regions where hadrosaurids never arrived: All alleged subantarctic and Antarctic remains of hadrosaurids could belong to non-hadrosaurid duckbills like Gonkoken. Dinosaur faunas of the world underwent qualitatively different changes before the Cretaceous-Paleogene asteroid impact, which should be considered when discussing their possible vulnerability.
Collapse
Affiliation(s)
- Jhonatan Alarcón-Muñoz
- Red Paleontológica U-Chile, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
- Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
- Área Paleontología, Museo Nacional de Historia Natural de Chile, Santiago, Chile
| | - Alexander O. Vargas
- Red Paleontológica U-Chile, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Hans P. Püschel
- Red Paleontológica U-Chile, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
- School of GeoSciences, University of Edinburgh, Grant Institute, Edinburgh, UK
| | - Sergio Soto-Acuña
- Red Paleontológica U-Chile, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
- Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
- KayTreng Consultores SpA, Ñuñoa, Santiago, Chile
- Escuela de Geología, Facultad de Ciencias, Universidad Mayor, Manuel Montt 367, Providencia, Santiago, Chile
| | | | - Marcelo Leppe
- Laboratorio de Paleobiología, Instituto Nacional Antártico Chileno, Punta Arenas, Chile
| | - Jonatan Kaluza
- Fundación Félix de Azara, Argentina, CONICET, Buenos Aires, Argentina
| | - Verónica Milla
- Red Paleontológica U-Chile, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
- Universidad de Concepción, Concepción, Chile
| | - Carolina S. Gutstein
- Red Paleontológica U-Chile, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
- Paleo Consultores, Pedro de Valdivia 273, Providencia 1602, Chile
| | - José Palma-Liberona
- Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Wolfgang Stinnesbeck
- Institut für Geowissenschaften, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 234-236, Heidelberg 69120, Germany
| | - Eberhard Frey
- Staatliches Museum für Naturkunde Karlsruhe (SMNK), Erbprinzenstraße 13, Karlsruhe 76133, Germany
| | - Juan Pablo Pino
- Red Paleontológica U-Chile, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
- Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Dániel Bajor
- Red Paleontológica U-Chile, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
- Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Elaine Núñez
- Red Paleontológica U-Chile, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
- Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Héctor Ortiz
- Red Paleontológica U-Chile, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
- Universidad de Magallanes, Punta Arenas, Chile
| | - David Rubilar-Rogers
- Área Paleontología, Museo Nacional de Historia Natural de Chile, Santiago, Chile
| | - Penélope Cruzado-Caballero
- Área de Paleontología, Departamento de Biología Animal, Edafología y Geología, Universidad de La Laguna, Tenerife, Spain
- Grupo Aragosaurus-IUCA, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain
| |
Collapse
|
3
|
Zanno LE, Gates TA, Avrahami HM, Tucker RT, Makovicky PJ. An early-diverging iguanodontian (Dinosauria: Rhabdodontomorpha) from the Late Cretaceous of North America. PLoS One 2023; 18:e0286042. [PMID: 37285376 DOI: 10.1371/journal.pone.0286042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 05/08/2023] [Indexed: 06/09/2023] Open
Abstract
Intensifying macrovertebrate reconnaissance together with refined age-dating of mid-Cretaceous assemblages in recent decades is producing a more nuanced understanding of the impact of the Cretaceous Thermal Maximum on terrestrial ecosystems. Here we report discovery of a new early-diverging ornithopod, Iani smithi gen. et sp. nov., from the Cenomanian-age lower Mussentuchit Member, Cedar Mountain Formation of Utah, USA. The single known specimen of this species (NCSM 29373) includes a well-preserved, disarticulated skull, partial axial column, and portions of the appendicular skeleton. Apomorphic traits are concentrated on the frontal, squamosal, braincase, and premaxilla, including the presence of three premaxillary teeth. Phylogenetic analyses using parsimony and Bayesian inference posit Iani as a North American rhabdodontomorph based on the presence of enlarged, spatulate teeth bearing up to 12 secondary ridges, maxillary teeth lacking a primary ridge, a laterally depressed maxillary process of the jugal, and a posttemporal foramen restricted to the squamosal, among other features. Prior to this discovery, neornithischian paleobiodiversity in the Mussentuchit Member was based primarily on isolated teeth, with only the hadrosauroid Eolambia caroljonesa named from macrovertebrate remains. Documentation of a possible rhabdodontomorph in this assemblage, along with published reports of an as-of-yet undescribed thescelosaurid, and fragmentary remains of ankylosaurians and ceratopsians confirms a minimum of five, cohabiting neornithischian clades in earliest Late Cretaceous terrestrial ecosystems of North America. Due to poor preservation and exploration of Turonian-Santonian assemblages, the timing of rhabdodontomorph extirpation in the Western Interior Basin is, as of yet, unclear. However, Iani documents survival of all three major clades of Early Cretaceous neornithischians (Thescelosauridae, Rhabdodontomorpha, and Ankylopollexia) into the dawn of the Late Cretaceous of North America.
Collapse
Affiliation(s)
- Lindsay E Zanno
- Paleontology, North Carolina Museum of Natural Sciences, Raleigh, North Carolina, United States of America
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Terry A Gates
- Paleontology, North Carolina Museum of Natural Sciences, Raleigh, North Carolina, United States of America
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Haviv M Avrahami
- Paleontology, North Carolina Museum of Natural Sciences, Raleigh, North Carolina, United States of America
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Ryan T Tucker
- Department of Earth Sciences, Stellenbosch University, Stellenbosch, South Africa
| | - Peter J Makovicky
- Department of Earth and Environmental Sciences, University of Minnesota, Minneapolis, Minnesota, United States of America
| |
Collapse
|
4
|
Suarez CA, Frederickson J, Cifelli RL, Pittman JG, Nydam RL, Hunt-Foster RK, Morgan K. A new vertebrate fauna from the Lower Cretaceous Holly Creek Formation of the Trinity Group, southwest Arkansas, USA. PeerJ 2021; 9:e12242. [PMID: 34721970 PMCID: PMC8542373 DOI: 10.7717/peerj.12242] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 09/12/2021] [Indexed: 11/20/2022] Open
Abstract
We present a previously discovered but undescribed late Early Cretaceous vertebrate fauna from the Holly Creek Formation of the Trinity Group in Arkansas. The site from the ancient Gulf Coast is dominated by semi-aquatic forms and preserves a diverse aquatic, semi-aquatic, and terrestrial fauna. Fishes include fresh- to brackish-water chondrichthyans and a variety of actinopterygians, including semionotids, an amiid, and a new pycnodontiform, Anomoeodus caddoi sp. nov. Semi-aquatic taxa include lissamphibians, the solemydid turtle Naomichelys, a trionychid turtle, and coelognathosuchian crocodyliforms. Among terrestrial forms are several members of Dinosauria and one or more squamates, one of which, Sciroseps pawhuskai gen. et sp. nov., is described herein. Among Dinosauria, both large and small theropods (Acrocanthosaurus, Deinonychus, and Richardoestesia) and titanosauriform sauropods are represented; herein we also report the first occurrence of a nodosaurid ankylosaur from the Trinity Group. The fauna of the Holly Creek Formation is similar to other, widely scattered late Early Cretaceous assemblages across North America and suggests the presence of a low-diversity, broadly distributed continental ecosystem of the Early Cretaceous following the Late Jurassic faunal turnover. This low-diversity ecosystem contrasts sharply with the highly diverse ecosystem which emerged by the Cenomanian. The contrast underpins the importance of vicariance as an evolutionary driver brought on by Sevier tectonics and climatic changes, such as rising sea level and formation of the Western Interior Seaway, impacting the early Late Cretaceous ecosystem.
Collapse
Affiliation(s)
- Celina A Suarez
- Department of Geosciences, University of Arkansas at Fayetteville, Fayetteville, Arkansas, USA
| | - Joseph Frederickson
- Weis Earth Science Museum, University of Wisconsin Oshkosh Fox Cities Campus, Menasha, WI, USA
| | - Richard L Cifelli
- Department of Vertebrate Paleontology, Sam Noble Oklahoma Museum of Natural History, University of Oklahoma, Norman, OK, USA
| | | | - Randall L Nydam
- Arizona College of Osteopathic Medicine, Midwestern University, Glendale, Arizona, USA
| | | | - Kirsty Morgan
- Department of Geosciences, University of Arkansas at Fayetteville, Fayetteville, Arkansas, USA
| |
Collapse
|
5
|
Liao CC, Moore A, Jin C, Yang TR, Shibata M, Jin F, Wang B, Jin D, Guo Y, Xu X. A possible brachiosaurid (Dinosauria, Sauropoda) from the mid-Cretaceous of northeastern China. PeerJ 2021; 9:e11957. [PMID: 34484987 PMCID: PMC8381880 DOI: 10.7717/peerj.11957] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 07/21/2021] [Indexed: 11/30/2022] Open
Abstract
Brachiosauridae is a lineage of titanosauriform sauropods that includes some of the most iconic non-avian dinosaurs. Undisputed brachiosaurid fossils are known from the Late Jurassic through the Early Cretaceous of North America, Africa, and Europe, but proposed occurrences outside this range have proven controversial. Despite occasional suggestions that brachiosaurids dispersed into Asia, to date no fossils have provided convincing evidence for a pan-Laurasian distribution for the clade, and the failure to discover brachiosaurid fossils in the well-sampled sauropod-bearing horizons of the Early Cretaceous of Asia has been taken to evidence their genuine absence from the continent. Here we report on an isolated sauropod maxilla from the middle Cretaceous (Albian-Cenomanian) Longjing Formation of the Yanji basin of northeast China. Although the specimen preserves limited morphological information, it exhibits axially twisted dentition, a shared derived trait otherwise known only in brachiosaurids. Referral of the specimen to the Brachiosauridae receives support from phylogenetic analysis under both equal and implied weights parsimony, providing the most convincing evidence to date that brachiosaurids dispersed into Asia at some point in their evolutionary history. Inclusion in our phylogenetic analyses of an isolated sauropod dentary from the same site, for which an association with the maxilla is possible but uncertain, does not substantively alter these results. We consider several paleobiogeographic scenarios that could account for the occurrence of a middle Cretaceous Asian brachiosaurid, including dispersal from either North America or Europe during the Early Cretaceous. The identification of a brachiosaurid in the Longshan fauna, and the paleobiogeographic histories that could account for its presence there, are hypotheses that can be tested with continued study and excavation of fossils from the Longjing Formation.
Collapse
Affiliation(s)
- Chun-Chi Liao
- Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Beijing, China
- CAS Center for Excellence in Life and Paleoenvironment, Beijing, Beijing, China
- University of Chinese Academy of Sciences, Beijing, Beijing, China
| | - Andrew Moore
- Department of Anatomical Sciences, Renaissance School of Medicine at Stony Brook University, NY, USA
| | - Changzhu Jin
- Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Beijing, China
- CAS Center for Excellence in Life and Paleoenvironment, Beijing, Beijing, China
| | - Tzu-Ruei Yang
- Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Beijing, China
- CAS Center for Excellence in Life and Paleoenvironment, Beijing, Beijing, China
| | - Masateru Shibata
- Fukui Prefectural Dinosaur Museum, Fukui, Japan
- Institute of Dinosaur Research, Fukui Prefectural University, Fukui, Japan
| | - Feng Jin
- Yanji Municipal Bureau of Land and Resources, Yanji, China
- Yanji Paleontological Research Centre, Yanji, China
- Yanji Dinosaur Museum, Yanji, China
| | - Bing Wang
- Yanji Municipal Bureau of Land and Resources, Yanji, China
- Yanji Paleontological Research Centre, Yanji, China
- Yanji Dinosaur Museum, Yanji, China
| | - Dongchun Jin
- Yanji Municipal Bureau of Land and Resources, Yanji, China
- Yanji Paleontological Research Centre, Yanji, China
- Yanji Dinosaur Museum, Yanji, China
| | - Yu Guo
- The Geological Museum of China, Beijing, Beijing, China
| | - Xing Xu
- Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Beijing, China
- CAS Center for Excellence in Life and Paleoenvironment, Beijing, Beijing, China
| |
Collapse
|
6
|
Cilliers CD, Tucker RT, Crowley JL, Zanno LE. Age constraint for the Moreno Hill Formation (Zuni Basin) by CA-TIMS and LA-ICP-MS detrital zircon geochronology. PeerJ 2021; 9:e10948. [PMID: 33854833 PMCID: PMC7953880 DOI: 10.7717/peerj.10948] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 01/26/2021] [Indexed: 11/20/2022] Open
Abstract
The “mid-Cretaceous” (~125–80 Ma) was punctuated by major plate-tectonic upheavals resulting in widespread volcanism, mountain-building, eustatic sea-level changes, and climatic shifts that together had a profound impact on terrestrial biotic assemblages. Paleontological evidence suggests terrestrial ecosystems underwent a major restructuring during this interval, yet the pace and pattern are poorly constrained. Current impediments to piecing together the geologic and biological history of the “mid-Cretaceous” include a relative paucity of terrestrial outcrop stemming from this time interval, coupled with a historical understudy of fragmentary strata. In the Western Interior of North America, sedimentary strata of the Turonian–Santonian stages are emerging as key sources of data for refining the timing of ecosystem transformation during the transition from the late-Early to early-Late Cretaceous. In particular, the Moreno Hill Formation (Zuni Basin, New Mexico) is especially important for detailing the timing of the rise of iconic Late Cretaceous vertebrate faunas. This study presents the first systematic geochronological framework for key strata within the Moreno Hill Formation. Based on the double-dating of (U-Pb) detrital zircons, via CA-TIMS and LA-ICP-MS, we interpret two distinct depositional phases of the Moreno Hill Formation (initial deposition after 90.9 Ma (middle Turonian) and subsequent deposition after 88.6 Ma (early Coniacian)), younger than previously postulated based on correlations with marine biostratigraphy. Sediment and the co-occurring youthful subset of zircons are sourced from the southwestern Cordilleran Arc and Mogollon Highlands, which fed into the landward portion of the Gallup Delta (the Moreno Hill Formation) via northeasterly flowing channel complexes. This work greatly strengthens linkages to other early Late Cretaceous strata across the Western Interior.
Collapse
Affiliation(s)
- Charl D Cilliers
- Department of Earth Sciences, Faculty of Science, Stellenbosch University, Stellenbosch, Western Cape, South Africa
| | - Ryan T Tucker
- Department of Earth Sciences, Faculty of Science, Stellenbosch University, Stellenbosch, Western Cape, South Africa
| | - James L Crowley
- Department of Geosciences, Boise State University, Boise, ID, USA
| | - Lindsay E Zanno
- Paleontology, North Carolina Museum of Natural Sciences, Raleigh, NC, USA.,Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
| |
Collapse
|
7
|
Funston GF, Chinzorig T, Tsogtbaatar K, Kobayashi Y, Sullivan C, Currie PJ. A new two-fingered dinosaur sheds light on the radiation of Oviraptorosauria. ROYAL SOCIETY OPEN SCIENCE 2020; 7:201184. [PMID: 33204472 PMCID: PMC7657903 DOI: 10.1098/rsos.201184] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 09/07/2020] [Indexed: 06/11/2023]
Abstract
Late Cretaceous trends in Asian dinosaur diversity are poorly understood, but recent discoveries have documented a radiation of oviraptorosaur theropods in China and Mongolia. However, little work has addressed the factors that facilitated this diversification. A new oviraptorid from the Late Cretaceous of Mongolia sheds light on the evolution of the forelimb, which appears to have played a role in the radiation of oviraptorosaurs. Surprisingly, the reduced arm has only two functional digits, highlighting a previously unrecognized occurrence of digit loss in theropods. Phylogenetic analysis shows that the onset of this reduction coincides with the radiation of heyuannine oviraptorids, following dispersal from southern China into the Gobi region. This suggests expansion into a new niche in the Gobi region, which relied less on the elongate, grasping forelimbs inherited by oviraptorosaurs. Variation in forelimb length and manus morphology provides another example of niche partitioning in oviraptorosaurs, which may have made possible their incredible diversity in the latest Cretaceous of Asia.
Collapse
Affiliation(s)
- Gregory F. Funston
- School of GeoSciences, University of Edinburgh, Edinburgh, UK
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Tsogtbaatar Chinzorig
- Hokkaido University Museum, Hokkaido University, Sapporo, Japan
- Institute of Paleontology, Mongolian Academy of Sciences, Ulaanbaatar, Mongolia
| | | | | | - Corwin Sullivan
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
- Philip J. Currie Dinosaur Museum, Wembley, Alberta, Canada
| | - Philip J. Currie
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| |
Collapse
|
8
|
Dinosaur ichnology and sedimentology of the Chignik Formation (Upper Cretaceous), Aniakchak National Monument, southwestern Alaska; Further insights on habitat preferences of high-latitude hadrosaurs. PLoS One 2019; 14:e0223471. [PMID: 31665132 PMCID: PMC6821036 DOI: 10.1371/journal.pone.0223471] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 09/12/2019] [Indexed: 11/19/2022] Open
Abstract
While there are now numerous records of dinosaurs from Cretaceous rocks around the state of Alaska, very few fossil records of terrestrial vertebrates are known from the Mesozoic rocks of the southwestern part of the state. Here we report the new discovery of extensive occurrences of dinosaur tracks from Aniakchak National Monument of the Alaska Peninsula. These tracks are in the Late Cretaceous (Maastrichtian) Chignik Formation, a cyclic sequence of rocks, approximately 500-600 m thick, representing shallow marine to nearshore marine environments in the lower part and continental alluvial coastal plain environments in the upper part of the section. These rocks are part of the Peninsular Terrane and paleomagnetic reconstructions based on the volcanic rocks of this terrane suggest that the Chignik Formation was deposited at approximately its current latitude which is almost 57° N. Recent field work in Aniakchak National Monument has revealed over 75 new track sites, dramatically increasing the dinosaur record from the Alaska Peninsula. Most of the combined record of tracks can be attributed to hadrosaurs, the plant-eating duck-billed dinosaurs. Tracks range in size from those made by full-grown adults to juveniles. Other tracks can be attributed to armored dinosaurs, meat-eating dinosaurs, and two kinds of fossil birds. The track size of the predatory dinosaur suggests a body approximately 6-7 m long, about the estimated size of the North Slope tyrannosaurid Nanuqsaurus. The larger bird tracks resemble Magnoavipes denaliensis previously described from Denali National Park, while the smaller bird tracks were made by a bird about the size of a modern Willet. Previous interdisciplinary sedimentologic and paleontologic work in the correlative and well-known dinosaur bonebeds of the Prince Creek Formation 1400km-1500km further north in Alaska suggested that high-latitude hadrosaurs preferred distal coastal plain or lower delta plain habitats. The ichnological record being uncovered in the Chignik Formation of southwestern Alaska is showing that the hadrosaur tracks here were also made in distal coastal and delta plain conditions. This similarity may corroborate the habitat preference model for Cretaceous high-latitude dinosaurs proposed for the data gathered from the Prince Creek Formation, and may indicate that at least Beringian hadrosaurids had similar habitat preferences regardless of latitude.
Collapse
|
9
|
D'Emic MD, Foreman BZ, Jud NA, Britt BB, Schmitz M, Crowley JL. Chronostratigraphic Revision of the Cloverly Formation (Lower Cretaceous, Western Interior, USA). BULLETIN OF THE PEABODY MUSEUM OF NATURAL HISTORY 2019. [DOI: 10.3374/014.060.0101] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Michael D. D'Emic
- Department of Anatomical Sciences, Health Sciences Center, Stony Brook University, Stony Brook, NY 11794 USA
| | - Brady Z. Foreman
- Department of Geology, Western Washington University, Bellingham, WA 98225 USA —
| | - Nathan A. Jud
- School of Integrative Plant Science, Cornell University, Ithaca, NY 14853 USA —
| | - Brooks B. Britt
- Department of Geological Sciences, Brigham Young University, Provo, UT 84602 USA —
| | - Mark Schmitz
- Department of Geosciences, Boise State University, Boise, ID 83725 USA —,
| | - James L. Crowley
- Department of Geosciences, Boise State University, Boise, ID 83725 USA —,
| |
Collapse
|
10
|
Zanno LE, Tucker RT, Canoville A, Avrahami HM, Gates TA, Makovicky PJ. Diminutive fleet-footed tyrannosauroid narrows the 70-million-year gap in the North American fossil record. Commun Biol 2019; 2:64. [PMID: 30820466 PMCID: PMC6385174 DOI: 10.1038/s42003-019-0308-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 01/08/2019] [Indexed: 11/23/2022] Open
Abstract
To date, eco-evolutionary dynamics in the ascent of tyrannosauroids to top predator roles have been obscured by a 70-million-year gap in the North American (NA) record. Here we report discovery of the oldest Cretaceous NA tyrannosauroid, extending the lineage by ~15 million years. The new taxon—Moros intrepidus gen. et sp. nov.—is represented by a hind limb from an individual nearing skeletal maturity at 6–7 years. With a ~1.2-m limb length and 78-kg mass, M. intrepidus ranks among the smallest Cretaceous tyrannosauroids, restricting the window for rapid mass increases preceding the appearance of colossal eutyrannosaurs. Phylogenetic affinity with Asian taxa supports transcontinental interchange as the means by which iconic biotas of the terminal Cretaceous were established in NA. The unexpectedly diminutive and highly cursorial bauplan of NA’s earliest Cretaceous tyrannosauroids reveals an evolutionary strategy reliant on speed and small size during their prolonged stint as marginal predators. Lindsay Zanno et al. report the discovery of a new tyrannosaur that helps to fill in a 70 million year gap in the fossil record. This new species reveals that the earliest North American tyrannosaurs relied on speed and small body size to survive and that apex predator status and large body sizes were not reached until much later in their evolutionary history.
Collapse
Affiliation(s)
- Lindsay E Zanno
- Paleontology, North Carolina Museum of Natural Sciences, 11W. Jones, St. Raleigh, NC, 27601, USA. .,Department of Biological Sciences, North Carolina State University, 100 Brooks Ave., Raleigh, NC, 27607, USA. .,Section of Earth Sciences, Field Museum of Natural History, 1400S. Lake Shore Dr., Chicago, IL, 60605, USA.
| | - Ryan T Tucker
- Department of Earth Sciences, Stellenbosch University, Private Bag X1 Matieland, Stellenbosch, 7602, South Africa
| | - Aurore Canoville
- Paleontology, North Carolina Museum of Natural Sciences, 11W. Jones, St. Raleigh, NC, 27601, USA.,Department of Biological Sciences, North Carolina State University, 100 Brooks Ave., Raleigh, NC, 27607, USA
| | - Haviv M Avrahami
- Paleontology, North Carolina Museum of Natural Sciences, 11W. Jones, St. Raleigh, NC, 27601, USA.,Department of Biological Sciences, North Carolina State University, 100 Brooks Ave., Raleigh, NC, 27607, USA
| | - Terry A Gates
- Paleontology, North Carolina Museum of Natural Sciences, 11W. Jones, St. Raleigh, NC, 27601, USA.,Department of Biological Sciences, North Carolina State University, 100 Brooks Ave., Raleigh, NC, 27607, USA
| | - Peter J Makovicky
- Section of Earth Sciences, Field Museum of Natural History, 1400S. Lake Shore Dr., Chicago, IL, 60605, USA
| |
Collapse
|
11
|
Frederickson JA, Engel MH, Cifelli RL. Niche Partitioning in Theropod Dinosaurs: Diet and Habitat Preference in Predators from the Uppermost Cedar Mountain Formation (Utah, U.S.A.). Sci Rep 2018; 8:17872. [PMID: 30552378 PMCID: PMC6294763 DOI: 10.1038/s41598-018-35689-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 11/08/2018] [Indexed: 11/09/2022] Open
Abstract
We explore hypothetical ecologies to explain diversity among predatory dinosaurs in North America's medial Cretaceous, based on occurrence, tooth morphology, and stable isotope analysis. The Mussentuchit local fauna, Utah, USA, is among the best-known terrestrial vertebrate assemblages from the Cretaceous. Study samples include teeth from six microvertebrate sites, ranging in depositional setting from distal floodplain to channel lags. We recognize four theropod morphotypes: a comparatively large theropod (morph 1), a medium-sized dromaeosaurid (morph 2), a small dromaeosaurid (morph 3), and a tooth-morph similar to the genus Richardoestesia (morph 4). These four morphotypes vary significantly in mean size, from 15.1 mm in the largest theropod to 3.7 mm in Richardoestesia. Further, tooth representation from two of the best-sampled microsites (representing a channel/splay and floodplain deposit) show differing patterns of abundances with morphs 1 and 3 having roughly the same abundance in both sites, while morph 2 was more abundant in the floodplain setting and morph 4 was more abundant in the channel/splay. Stable isotope analysis (δ13C; δ18O) of tooth carbonate from the theropod morphotypes, goniopholidid crocodilians, and matrix (to test for diagenesis) from these sites were also analyzed. The theropods show modest differences in δ13C values between each other, with carbonate from the teeth of morphs 1, 3, and 4 being enriched in 13C for the channel/splay relative to the floodplain environments, possibly indicative of dietary plasticity in these species. We hypothesize that these data indicate that the Mussentuchit theropods had different niches within the predator guild, suggesting plausible means by which ecospace was divided among the predatory dinosaurs of the Mussentuchit local fauna.
Collapse
Affiliation(s)
- J A Frederickson
- Department of Biological Sciences, Southwestern Oklahoma State University, 100 Campus Drive, Weatherford, OK, 73096, USA. .,Department of Biology, University of Oklahoma, Norman, Oklahoma, 73072, USA. .,Sam Noble Museum, 2401 Chautauqua Avenue, Norman, Oklahoma, 73072, USA.
| | - M H Engel
- School of Geology and Geophysics, University of Oklahoma, Norman, Oklahoma, 73072, USA
| | - R L Cifelli
- Department of Biology, University of Oklahoma, Norman, Oklahoma, 73072, USA.,Sam Noble Museum, 2401 Chautauqua Avenue, Norman, Oklahoma, 73072, USA
| |
Collapse
|
12
|
Avrahami HM, Gates TA, Heckert AB, Makovicky PJ, Zanno LE. A new microvertebrate assemblage from the Mussentuchit Member, Cedar Mountain Formation: insights into the paleobiodiversity and paleobiogeography of early Late Cretaceous ecosystems in western North America. PeerJ 2018; 6:e5883. [PMID: 30479889 PMCID: PMC6241397 DOI: 10.7717/peerj.5883] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 10/08/2018] [Indexed: 11/30/2022] Open
Abstract
The vertebrate fauna of the Late Cretaceous Mussentuchit Member of the Cedar Mountain Formation has been studied for nearly three decades, yet the fossil-rich unit continues to produce new information about life in western North America approximately 97 million years ago. Here we report on the composition of the Cliffs of Insanity (COI) microvertebrate locality, a newly sampled site containing perhaps one of the densest concentrations of microvertebrate fossils yet discovered in the Mussentuchit Member. The COI locality preserves osteichthyan, lissamphibian, testudinatan, mesoeucrocodylian, dinosaurian, metatherian, and trace fossil remains and is among the most taxonomically rich microvertebrate localities in the Mussentuchit Member. To better refine taxonomic identifications of isolated theropod dinosaur teeth, we used quantitative analyses of taxonomically comprehensive databases of theropod tooth measurements, adding new data on theropod tooth morphodiversity in this poorly understood interval. We further provide the first descriptions of tyrannosauroid premaxillary teeth and document the earliest North American record of adocid remains, extending the appearance of this ancestrally Asian clade by 5 million years in western North America and supporting studies of pre-Cenomaninan Laurasian faunal exchange across Beringia. The overabundance of mesoeucrocodylian remains at the COI locality produces a comparatively low measure of relative biodiversity when compared to other microvertebrate sites in the Mussentuchit Member using both raw and subsampling methods. Much more microvertebrate research is necessary to understand the roles of changing ecology and taphonomy that may be linked to transgression of the Western Interior Seaway or microhabitat variation.
Collapse
Affiliation(s)
- Haviv M Avrahami
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA.,North Carolina Museum of Natural Sciences, Raleigh, NC, USA.,Department of Geological and Environmental Sciences, Appalachian State University, Boone, NC, USA
| | - Terry A Gates
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
| | - Andrew B Heckert
- Department of Geological and Environmental Sciences, Appalachian State University, Boone, NC, USA
| | | | - Lindsay E Zanno
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA.,North Carolina Museum of Natural Sciences, Raleigh, NC, USA
| |
Collapse
|
13
|
An unusual association of hadrosaur and therizinosaur tracks within Late Cretaceous rocks of Denali National Park, Alaska. Sci Rep 2018; 8:11706. [PMID: 30076347 PMCID: PMC6076232 DOI: 10.1038/s41598-018-30110-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 07/05/2018] [Indexed: 12/03/2022] Open
Abstract
We report details of a unique association of hadrosaur and therizinosaur tracks found in the Late Cretaceous lower Cantwell Formation, Denali National Park, central Alaska Range, Alaska. This rock unit is now well-documented as a source of thousands of fossil footprints of vertebrates such as fishes, pterosaurs, and avialan and non-avialan dinosaurs. The lower Cantwell Formation in this area consists of numerous fining-upward successions of conglomerates and pebbly sandstones, cross-stratified and massive sandstones, interbedded sandstones and siltstones, organic-rich siltstones and shales, and rare, thin, bentonites, typically bounded by thin coal seams, and it contains a diverse fossil flora. We report the first North American co-occurrence of tracks attributable to hadrosaurs and therizinosaurs in the lower Cantwell Formation. Although previously un-reported in North America, this association of hadrosaur and therizinosaur tracks is more characteristic of the correlative Nemegt Formation in central Asia, perhaps suggesting that parameters defining the continental ecosystem of central Asia were also present in this part of Alaska during the Latest Cretaceous.
Collapse
|
14
|
Gates TA, Tsogtbaatar K, Zanno LE, Chinzorig T, Watabe M. A new iguanodontian (Dinosauria: Ornithopoda) from the Early Cretaceous of Mongolia. PeerJ 2018; 6:e5300. [PMID: 30083450 PMCID: PMC6078070 DOI: 10.7717/peerj.5300] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 07/03/2018] [Indexed: 11/20/2022] Open
Abstract
We describe a new iguanodontian ornithopod, Choyrodon barsboldi gen. et sp. nov. from the Albian-aged Khuren Dukh Formation of Mongolia based on several partial skeletons interpreted to represent a subadult growth stage based on osteohistological features. This new taxon is diagnosed by many autapomorphies of the maxilla, nasal, lacrimal, opisthotic, predentary, and surangular. Choyrodon displays an unusual combination of traits, possessing an open antorbital fenestra (a primitive ornithopod trait) together with derived features such as a downturned dentary and enlarged narial fenestra. Histological imaging suggests that the type specimen of Choyrodon would have been a subadult at the time of death. Phylogenetic analysis of two different character matrices do not posit Choyrodon to be the sister taxon or to be more primitive than the iguanodontian Altirhinus kurzanovi, which is found in the same formation. The only resolved relationship of this new taxon is that it was hypothesized to be a sister-taxon with the North American species Eolambia caroljonesa. Though discovered in the same formation and Choyrodon being smaller-bodied than Altirhinus, it does not appear that the former species is an ontogimorph of the latter. Differences in morphology and results of the phylogenetic analyses support their distinction although more specimens of both species will allow better refinement of their uniqueness.
Collapse
Affiliation(s)
- Terry A Gates
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA.,Paleontology Unit, North Carolina Museum of Natural Sciences, Raleigh, NC, USA
| | - Khishigjav Tsogtbaatar
- Department of Paleontology, Institute of Paleontology and Geology, Mongolian Academy of Sciences, Ulaanbataar, Mongolia
| | - Lindsay E Zanno
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA.,Paleontology Unit, North Carolina Museum of Natural Sciences, Raleigh, NC, USA
| | - Tsogtbaatar Chinzorig
- Department of Paleontology, Institute of Paleontology and Geology, Mongolian Academy of Sciences, Ulaanbataar, Mongolia.,Department of Natural History and Earth Sciences, Faculty of Sciences, Hokkaido University, Hokkaido University Museum, Sapporo, Japan
| | - Mahito Watabe
- School of International Liberal Studies, Waseda University, Tokyo, Japan
| |
Collapse
|
15
|
Brownstein CD. A Tyrannosauroid from the Lower Cenomanian of New Jersey and Its Evolutionary and Biogeographic Implications. BULLETIN OF THE PEABODY MUSEUM OF NATURAL HISTORY 2018. [DOI: 10.3374/014.058.0210] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
16
|
Matsumoto R, Evans SE. The first record of albanerpetontid amphibians (Amphibia: Albanerpetontidae) from East Asia. PLoS One 2018; 13:e0189767. [PMID: 29298317 PMCID: PMC5752013 DOI: 10.1371/journal.pone.0189767] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 11/29/2017] [Indexed: 11/18/2022] Open
Abstract
Albanerpetontids are an enigmatic fossil amphibian group known from deposits of Middle Jurassic to Pliocene age. The oldest and youngest records are from Europe, but the group appeared in North America in the late Early Cretaceous and radiated there during the Late Cretaceous. Until now, the Asian record has been limited to fragmentary specimens from the Late Cretaceous of Uzbekistan. This led to speculation that albanerpetontids migrated into eastern Asia from North America in the Albian to Cenomanian interval via the Beringian land bridge. However, here we describe albanerpetontid specimens from the Lower Cretaceous Kuwajima Formation of Japan, a record that predates their first known occurrence in North America. One specimen, an association of skull and postcranial bones from a single small individual, permits the diagnosis of a new taxon. High Resolution X-ray Computed Microtomography has revealed previously unrecorded features of albanerpetontid skull morphology in three dimensions, including the presence of a supraoccipital and epipterygoids, neither of which occurs in any known lissamphibian. The placement of this new taxon within the current phylogenetic framework for Albanerpetontidae is complicated by a limited overlap of comparable elements, most notably the non-preservation of the premaxillae in the Japanese taxon. Nonetheless, phylogenetic analysis places the new taxon closer to Albanerpeton than to Anoualerpeton, Celtedens, or Wesserpeton, although Bootstrap support values are weak. The results also question the monophyly of Albanerpeton as currently defined.
Collapse
Affiliation(s)
- Ryoko Matsumoto
- Department of Zoology, Kanagawa Prefectural Museum of Natural History, Odawara, Kanagawa Prefecture, Japan
| | - Susan E. Evans
- Department of Cell and Developmental Biology, University College London, London, England
| |
Collapse
|
17
|
McDonald AT, Gates TA, Zanno LE, Makovicky PJ. Anatomy, taphonomy, and phylogenetic implications of a new specimen of Eolambia caroljonesa (Dinosauria: Ornithopoda) from the Cedar Mountain Formation, Utah, USA. PLoS One 2017; 12:e0176896. [PMID: 28489871 PMCID: PMC5425030 DOI: 10.1371/journal.pone.0176896] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 03/26/2017] [Indexed: 11/29/2022] Open
Abstract
Background Eolambia caroljonesa is the most abundant dinosaur in the lower Cenomanian Mussentuchit Member of the Cedar Mountain Formation of Utah, and one of the most completely known non-hadrosaurid iguanodontians from North America. In addition to the large holotype and paratype partial skulls, copious remains of skeletally immature individuals, including three bonebeds, have been referred to E. caroljonesa. Nevertheless, aspects of the postcranial anatomy of this taxon, particularly the pelvic girdle, have remained ambiguous due to the lack of associated postcranial material of larger, more mature individuals. Methodology/Principal findings Here we describe a recently discovered associated partial postcranial skeleton of a large Eolambia caroljonesa. This specimen, FMNH PR 3847, provides new anatomical data regarding the vertebral column and pelvic girdle, supplementing previous diagnoses and descriptions of E. caroljonesa. A new phylogenetic analysis incorporating information from FMNH PR 3847 places E. caroljonesa as a basal hadrosauromorph closely related to Protohadros byrdi from the Cenomanian Woodbine Formation of Texas. Histological analysis of FMNH PR 3847 reveals that it represents a subadult individual eight to nine years of age. Taphonomic analysis indicates that FMNH PR 3847 was preserved in a crevasse splay deposit, along with an unusual abundance of small crocodylomorph material. Conclusions/Significance FMNH PR 3847 provides a wealth of new morphological data, adding to the anatomical and systematic characterization of Eolambia caroljonesa, and histological data, revealing new information on growth history in a basal hadrosauromorph. Taphonomic characterization of FMNH PR 3847 and associated vertebrate material will allow comparison with other vertebrate localities in the Mussentuchit Member of the Cedar Mountain Formation.
Collapse
Affiliation(s)
- Andrew T. McDonald
- Saint Louis Science Center, Saint Louis, Missouri, United States of America
- * E-mail:
| | - Terry A. Gates
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, United States of America
- North Carolina Museum of Natural Sciences, Raleigh, North Carolina, United States of America
| | - Lindsay E. Zanno
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, United States of America
- North Carolina Museum of Natural Sciences, Raleigh, North Carolina, United States of America
| | - Peter J. Makovicky
- Section of Earth Sciences, Field Museum of Natural History, Chicago, Illinois, United States of America
| |
Collapse
|
18
|
Arbour VM, Currie PJ. Ankylosaurid dinosaur tail clubs evolved through stepwise acquisition of key features. J Anat 2015; 227:514-23. [PMID: 26332595 DOI: 10.1111/joa.12363] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/02/2015] [Indexed: 11/29/2022] Open
Abstract
Ankylosaurid ankylosaurs were quadrupedal, herbivorous dinosaurs with abundant dermal ossifications. They are best known for their distinctive tail club composed of stiff, interlocking vertebrae (the handle) and large, bulbous osteoderms (the knob), which may have been used as a weapon. However, tail clubs appear relatively late in the evolution of ankylosaurids, and seemed to have been present only in a derived clade of ankylosaurids during the last 20 million years of the Mesozoic Era. New evidence from mid Cretaceous fossils from China suggests that the evolution of the tail club occurred at least 40 million years earlier, and in a stepwise manner, with early ankylosaurids evolving handle-like vertebrae before the distal osteoderms enlarged and coossified to form a knob.
Collapse
Affiliation(s)
- Victoria M Arbour
- Paleontology and Geology Research Laboratory, North Carolina Museum of Natural Sciences, Raleigh, NC, USA.,Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA.,Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Philip J Currie
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| |
Collapse
|
19
|
Csiki-Sava Z, Buffetaut E, Ősi A, Pereda-Suberbiola X, Brusatte SL. Island life in the Cretaceous - faunal composition, biogeography, evolution, and extinction of land-living vertebrates on the Late Cretaceous European archipelago. Zookeys 2015; 469:1-161. [PMID: 25610343 PMCID: PMC4296572 DOI: 10.3897/zookeys.469.8439] [Citation(s) in RCA: 136] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 11/20/2014] [Indexed: 11/22/2022] Open
Abstract
The Late Cretaceous was a time of tremendous global change, as the final stages of the Age of Dinosaurs were shaped by climate and sea level fluctuations and witness to marked paleogeographic and faunal changes, before the end-Cretaceous bolide impact. The terrestrial fossil record of Late Cretaceous Europe is becoming increasingly better understood, based largely on intensive fieldwork over the past two decades, promising new insights into latest Cretaceous faunal evolution. We review the terrestrial Late Cretaceous record from Europe and discuss its importance for understanding the paleogeography, ecology, evolution, and extinction of land-dwelling vertebrates. We review the major Late Cretaceous faunas from Austria, Hungary, France, Spain, Portugal, and Romania, as well as more fragmentary records from elsewhere in Europe. We discuss the paleogeographic background and history of assembly of these faunas, and argue that they are comprised of an endemic 'core' supplemented with various immigration waves. These faunas lived on an island archipelago, and we describe how this insular setting led to ecological peculiarities such as low diversity, a preponderance of primitive taxa, and marked changes in morphology (particularly body size dwarfing). We conclude by discussing the importance of the European record in understanding the end-Cretaceous extinction and show that there is no clear evidence that dinosaurs or other groups were undergoing long-term declines in Europe prior to the bolide impact.
Collapse
Affiliation(s)
- Zoltán Csiki-Sava
- Department of Geology, Faculty of Geology and Geophysics, University of Bucharest, 1 N. Bălcescu Blvd, 010041 Bucharest, Romania
| | - Eric Buffetaut
- Centre National de la Recherche Scientifique, UMR 8538, Laboratoire de Géologie de l’Ecole Normale Supérieure, 24 rue Lhomond, 75231 Paris Cedex 05, France
| | - Attila Ősi
- MTA-ELTE Lendület Dinosaur Research Group, Pázmány Péter sétány 1/c, Budapest, 1117, Hungary
| | - Xabier Pereda-Suberbiola
- Universidad del País Vasco/Euskal Herriko Unibertsitatea, Facultad de Ciencia y Tecnología, Departamento de Estratigrafía y Paleontología, Apartado 644, 48080 Bilbao, Spain
| | - Stephen L. Brusatte
- School of GeoSciences, University of Edinburgh, Grant Institute, King’s Buildings, West Mains Road, Edinburgh EH9 3JW, UK
| |
Collapse
|
20
|
Williamson TE, Brusatte SL, Wilson GP. The origin and early evolution of metatherian mammals: the Cretaceous record. Zookeys 2014:1-76. [PMID: 25589872 PMCID: PMC4284630 DOI: 10.3897/zookeys.465.8178] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 11/16/2014] [Indexed: 11/12/2022] Open
Abstract
Metatherians, which comprise marsupials and their closest fossil relatives, were one of the most dominant clades of mammals during the Cretaceous and are the most diverse clade of living mammals after Placentalia. Our understanding of this group has increased greatly over the past 20 years, with the discovery of new specimens and the application of new analytical tools. Here we provide a review of the phylogenetic relationships of metatherians with respect to other mammals, discuss the taxonomic definition and diagnosis of Metatheria, outline the Cretaceous history of major metatherian clades, describe the paleobiology, biogeography, and macroevolution of Cretaceous metatherians, and provide a physical and climatic background of Cretaceous metatherian faunas. Metatherians are a clade of boreosphendian mammals that must have originated by the Late Jurassic, but the first unequivocal metatherian fossil is from the Early Cretaceous of Asia. Metatherians have the distinctive tightly interlocking occlusal molar pattern of tribosphenic mammals, but differ from Eutheria in their dental formula and tooth replacement pattern, which may be related to the metatherian reproductive process which includes an extended period of lactation followed by birth of extremely altricial young. Metatherians were widespread over Laurasia during the Cretaceous, with members present in Asia, Europe, and North America by the early Late Cretaceous. In particular, they were taxonomically and morphologically diverse and relatively abundant in the Late Cretaceous of western North America, where they have been used to examine patterns of biogeography, macroevolution, diversification, and extinction through the Late Cretaceous and across the Cretaceous-Paleogene (K-Pg) boundary. Metatherian diversification patterns suggest that they were not strongly affected by a Cretaceous Terrestrial Revolution, but they clearly underwent a severe extinction across the K-Pg boundary.
Collapse
Affiliation(s)
- Thomas E Williamson
- New Mexico Museum of Natural History and Science, 1801 Mountain Road, NW, Albuquerque, New Mexico 87104-1375, USA
| | | | - Gregory P Wilson
- Department of Biology and Burke Museum of Natural History and Culture, 24 Kincaid Hall, University of Washington, Seattle, Washington 98195-1800, USA
| |
Collapse
|
21
|
Farke AA, Maxwell WD, Cifelli RL, Wedel MJ. A Ceratopsian Dinosaur from the Lower Cretaceous of Western North America, and the Biogeography of Neoceratopsia. PLoS One 2014; 9:e112055. [PMID: 25494182 PMCID: PMC4262212 DOI: 10.1371/journal.pone.0112055] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 09/22/2014] [Indexed: 11/18/2022] Open
Abstract
The fossil record for neoceratopsian (horned) dinosaurs in the Lower Cretaceous of North America primarily comprises isolated teeth and postcrania of limited taxonomic resolution, hampering previous efforts to reconstruct the early evolution of this group in North America. An associated cranium and lower jaw from the Cloverly Formation (?middle–late Albian, between 104 and 109 million years old) of southern Montana is designated as the holotype for Aquilops americanus gen. et sp. nov. Aquilops americanus is distinguished by several autapomorphies, including a strongly hooked rostral bone with a midline boss and an elongate and sharply pointed antorbital fossa. The skull in the only known specimen is comparatively small, measuring 84 mm between the tips of the rostral and jugal. The taxon is interpreted as a basal neoceratopsian closely related to Early Cretaceous Asian taxa, such as Liaoceratops and Auroraceratops. Biogeographically, A. americanus probably originated via a dispersal from Asia into North America; the exact route of this dispersal is ambiguous, although a Beringian rather than European route seems more likely in light of the absence of ceratopsians in the Early Cretaceous of Europe. Other amniote clades show similar biogeographic patterns, supporting an intercontinental migratory event between Asia and North America during the late Early Cretaceous. The temporal and geographic distribution of Upper Cretaceous neoceratopsians (leptoceratopsids and ceratopsoids) suggests at least intermittent connections between North America and Asia through the early Late Cretaceous, likely followed by an interval of isolation and finally reconnection during the latest Cretaceous.
Collapse
Affiliation(s)
- Andrew A. Farke
- Raymond M. Alf Museum of Paleontology, Claremont, California, United States of America
- Sam Noble Oklahoma Museum of Natural History, Norman, Oklahoma, United States of America
- * E-mail:
| | - W. Desmond Maxwell
- Department of Biological Sciences, University of the Pacific, Stockton, California, United States of America
- Sam Noble Oklahoma Museum of Natural History, Norman, Oklahoma, United States of America
| | - Richard L. Cifelli
- Sam Noble Oklahoma Museum of Natural History, Norman, Oklahoma, United States of America
| | - Mathew J. Wedel
- Sam Noble Oklahoma Museum of Natural History, Norman, Oklahoma, United States of America
- College of Podiatric Medicine, Western University of Health Sciences, Pomona, California, United States of America
| |
Collapse
|
22
|
Williamson TE, Brusatte SL. Small theropod teeth from the Late Cretaceous of the San Juan Basin, northwestern New Mexico and their implications for understanding latest Cretaceous dinosaur evolution. PLoS One 2014; 9:e93190. [PMID: 24709990 PMCID: PMC3977837 DOI: 10.1371/journal.pone.0093190] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 02/28/2014] [Indexed: 12/02/2022] Open
Abstract
Studying the evolution and biogeographic distribution of dinosaurs during the latest Cretaceous is critical for better understanding the end-Cretaceous extinction event that killed off all non-avian dinosaurs. Western North America contains among the best records of Late Cretaceous terrestrial vertebrates in the world, but is biased against small-bodied dinosaurs. Isolated teeth are the primary evidence for understanding the diversity and evolution of small-bodied theropod dinosaurs during the Late Cretaceous, but few such specimens have been well documented from outside of the northern Rockies, making it difficult to assess Late Cretaceous dinosaur diversity and biogeographic patterns. We describe small theropod teeth from the San Juan Basin of northwestern New Mexico. These specimens were collected from strata spanning Santonian – Maastrichtian. We grouped isolated theropod teeth into several morphotypes, which we assigned to higher-level theropod clades based on possession of phylogenetic synapomorphies. We then used principal components analysis and discriminant function analyses to gauge whether the San Juan Basin teeth overlap with, or are quantitatively distinct from, similar tooth morphotypes from other geographic areas. The San Juan Basin contains a diverse record of small theropods. Late Campanian assemblages differ from approximately co-eval assemblages of the northern Rockies in being less diverse with only rare representatives of troodontids and a Dromaeosaurus-like taxon. We also provide evidence that erect and recurved morphs of a Richardoestesia-like taxon represent a single heterodont species. A late Maastrichtian assemblage is dominated by a distinct troodontid. The differences between northern and southern faunas based on isolated theropod teeth provide evidence for provinciality in the late Campanian and the late Maastrichtian of North America. However, there is no indication that major components of small-bodied theropod diversity were lost during the Maastrichtian in New Mexico. The same pattern seen in northern faunas, which may provide evidence for an abrupt dinosaur extinction.
Collapse
Affiliation(s)
- Thomas E. Williamson
- New Mexico Museum of Natural History and Science, Albuquerque, New Mexico, United States of America
- * E-mail:
| | - Stephen L. Brusatte
- School of GeoSciences, University of Edinburgh, Edinburgh, Scotland, United Kingdom
| |
Collapse
|
23
|
Zanno LE, Makovicky PJ. Neovenatorid theropods are apex predators in the Late Cretaceous of North America. Nat Commun 2013; 4:2827. [DOI: 10.1038/ncomms3827] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2013] [Accepted: 10/25/2013] [Indexed: 11/09/2022] Open
|
24
|
Jones MEH, Anderson CL, Hipsley CA, Müller J, Evans SE, Schoch RR. Integration of molecules and new fossils supports a Triassic origin for Lepidosauria (lizards, snakes, and tuatara). BMC Evol Biol 2013; 13:208. [PMID: 24063680 PMCID: PMC4016551 DOI: 10.1186/1471-2148-13-208] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 09/02/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Lepidosauria (lizards, snakes, tuatara) is a globally distributed and ecologically important group of over 9,000 reptile species. The earliest fossil records are currently restricted to the Late Triassic and often dated to 227 million years ago (Mya). As these early records include taxa that are relatively derived in their morphology (e.g. Brachyrhinodon), an earlier unknown history of Lepidosauria is implied. However, molecular age estimates for Lepidosauria have been problematic; dates for the most recent common ancestor of all lepidosaurs range between approximately 226 and 289 Mya whereas estimates for crown-group Squamata (lizards and snakes) vary more dramatically: 179 to 294 Mya. This uncertainty restricts inferences regarding the patterns of diversification and evolution of Lepidosauria as a whole. RESULTS Here we report on a rhynchocephalian fossil from the Middle Triassic of Germany (Vellberg) that represents the oldest known record of a lepidosaur from anywhere in the world. Reliably dated to 238-240 Mya, this material is about 12 million years older than previously known lepidosaur records and is older than some but not all molecular clock estimates for the origin of lepidosaurs. Using RAG1 sequence data from 76 extant taxa and the new fossil specimens two of several calibrations, we estimate that the most recent common ancestor of Lepidosauria lived at least 242 Mya (238-249.5), and crown-group Squamata originated around 193 Mya (176-213). CONCLUSION A Early/Middle Triassic date for the origin of Lepidosauria disagrees with previous estimates deep within the Permian and suggests the group evolved as part of the faunal recovery after the end-Permain mass extinction as the climate became more humid. Our origin time for crown-group Squamata coincides with shifts towards warmer climates and dramatic changes in fauna and flora. Most major subclades within Squamata originated in the Cretaceous postdating major continental fragmentation. The Vellberg fossil locality is expected to become an important resource for providing a more balanced picture of the Triassic and for bridging gaps in the fossil record of several other major vertebrate groups.
Collapse
Affiliation(s)
- Marc EH Jones
- Research Department of Cell and Developmental Biology, Anatomy Building, UCL, University College London, Gower Street, London WCIE 6BT, UK
- School of Earth and Environmental Sciences, The University of Adelaide, North Terrace, Adelaide, South Australia 5005, Australia
| | - Cajsa Lisa Anderson
- University of Gothenburg, Department of Plant and Environmental Sciences, Gothenburg, Sweden
| | - Christy A Hipsley
- Museum für Naturkunde – Leibniz-Institut für Evolutions- und Biodiversitätsforschung an der Humboldt-Universität zu Berlin, Berlin, Germany
| | - Johannes Müller
- Museum für Naturkunde – Leibniz-Institut für Evolutions- und Biodiversitätsforschung an der Humboldt-Universität zu Berlin, Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), 14195 Berlin, Germany
| | - Susan E Evans
- Research Department of Cell and Developmental Biology, Anatomy Building, UCL, University College London, Gower Street, London WCIE 6BT, UK
| | - Rainer R Schoch
- Staatliches Museum für Naturkunde, Rosenstein 1, D-70191, Stuttgart, Germany
| |
Collapse
|
25
|
Jones MEH, Anderson CL, Hipsley CA, Müller J, Evans SE, Schoch RR. Integration of molecules and new fossils supports a Triassic origin for Lepidosauria (lizards, snakes, and tuatara). BMC Evol Biol 2013. [PMID: 24063680 DOI: 10.1186/1471-2148-23-208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023] Open
Abstract
BACKGROUND Lepidosauria (lizards, snakes, tuatara) is a globally distributed and ecologically important group of over 9,000 reptile species. The earliest fossil records are currently restricted to the Late Triassic and often dated to 227 million years ago (Mya). As these early records include taxa that are relatively derived in their morphology (e.g. Brachyrhinodon), an earlier unknown history of Lepidosauria is implied. However, molecular age estimates for Lepidosauria have been problematic; dates for the most recent common ancestor of all lepidosaurs range between approximately 226 and 289 Mya whereas estimates for crown-group Squamata (lizards and snakes) vary more dramatically: 179 to 294 Mya. This uncertainty restricts inferences regarding the patterns of diversification and evolution of Lepidosauria as a whole. RESULTS Here we report on a rhynchocephalian fossil from the Middle Triassic of Germany (Vellberg) that represents the oldest known record of a lepidosaur from anywhere in the world. Reliably dated to 238-240 Mya, this material is about 12 million years older than previously known lepidosaur records and is older than some but not all molecular clock estimates for the origin of lepidosaurs. Using RAG1 sequence data from 76 extant taxa and the new fossil specimens two of several calibrations, we estimate that the most recent common ancestor of Lepidosauria lived at least 242 Mya (238-249.5), and crown-group Squamata originated around 193 Mya (176-213). CONCLUSION A Early/Middle Triassic date for the origin of Lepidosauria disagrees with previous estimates deep within the Permian and suggests the group evolved as part of the faunal recovery after the end-Permain mass extinction as the climate became more humid. Our origin time for crown-group Squamata coincides with shifts towards warmer climates and dramatic changes in fauna and flora. Most major subclades within Squamata originated in the Cretaceous postdating major continental fragmentation. The Vellberg fossil locality is expected to become an important resource for providing a more balanced picture of the Triassic and for bridging gaps in the fossil record of several other major vertebrate groups.
Collapse
Affiliation(s)
- Marc E H Jones
- Research Department of Cell and Developmental Biology, Anatomy Building, UCL, University College London, Gower Street, London WCIE 6BT, UK.
| | | | | | | | | | | |
Collapse
|
26
|
Osteology of the basal hadrosauroid Eolambia caroljonesa (Dinosauria: Ornithopoda) from the Cedar Mountain Formation of Utah. PLoS One 2012; 7:e45712. [PMID: 23077495 PMCID: PMC3471925 DOI: 10.1371/journal.pone.0045712] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Accepted: 08/22/2012] [Indexed: 11/19/2022] Open
Abstract
Background Eolambia caroljonesa is known from copious remains from the lower Cenomanian Mussentuchit Member of the Cedar Mountain Formation in eastern Utah; however, the taxon has been only briefly described. Thus, we present herein a complete osteological description of Eolambia. Methodology/Principal Findings The description of Eolambia presented here is based upon the holotype partial skeleton (CEUM 9758), paratype partial skull (CEUM 5212), and abundant disarticulated elements from two bonebeds that contain juvenile individuals. These remains allow the skeletal anatomy of Eolambia to be documented almost fully and a revised diagnosis to be proposed. Conclusions/Significance The description provided here facilitates comparisons between Eolambia and other iguanodontians and allows Eolambia to be coded for additional characters in phylogenetic analyses. The close affinity between Eolambia and Probactrosaurus gobiensis from the Early Cretaceous of China supports previous hypotheses of faunal interchange between Asia and North America in the early Late Cretaceous.
Collapse
|
27
|
McDonald AT. Phylogeny of basal iguanodonts (Dinosauria: Ornithischia): an update. PLoS One 2012; 7:e36745. [PMID: 22629328 PMCID: PMC3358318 DOI: 10.1371/journal.pone.0036745] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Accepted: 04/11/2012] [Indexed: 11/29/2022] Open
Abstract
The precise phylogenetic relationships of many non-hadrosaurid members of Iguanodontia, i.e., basal iguanodonts, have been unclear. Therefore, to investigate the global phylogeny of basal iguanodonts a comprehensive data matrix was assembled, including nearly every valid taxon of basal iguanodont. The matrix was analyzed in the program TNT, and the maximum agreement subtree of the resulting most parsimonious trees was then calculated in PAUP. Ordering certain multistate characters and omitting taxa through safe taxonomic reduction did not markedly improve resolution. The results provide some new information on the phylogeny of basal iguanodonts, pertaining especially to obscure or recently described taxa, and support some recent taxonomic revisions, such as the splitting of traditional "Camptosaurus" and "Iguanodon". The maximum agreement subtree also shows a close relationship between the Asian Probactrosaurus gobiensis and the North American Eolambia, supporting the previous hypothesis of faunal interchange between Asia and North America in the early Late Cretaceous. Nevertheless, the phylogenetic relationships of many basal iguanodonts remain ambiguous due to the high number of taxa removed from the maximum agreement subtree and poor resolution of consensus trees.
Collapse
Affiliation(s)
- Andrew T McDonald
- Department of Earth and Environmental Science, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
| |
Collapse
|
28
|
Eddy DR, Clarke JA. New information on the cranial anatomy of Acrocanthosaurus atokensis and its implications for the phylogeny of Allosauroidea (Dinosauria: Theropoda). PLoS One 2011; 6:e17932. [PMID: 21445312 PMCID: PMC3061882 DOI: 10.1371/journal.pone.0017932] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Accepted: 02/18/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Allosauroidea has a contentious taxonomic and systematic history. Within this group of theropod dinosaurs, considerable debate has surrounded the phylogenetic position of the large-bodied allosauroid Acrocanthosaurus atokensis from the Lower Cretaceous Antlers Formation of North America. Several prior analyses recover Acrocanthosaurus atokensis as sister taxon to the smaller-bodied Allosaurus fragilis known from North America and Europe, and others nest Acrocanthosaurus atokensis within Carcharodontosauridae, a large-bodied group of allosauroids that attained a cosmopolitan distribution during the Early Cretaceous. METHODOLOGY/PRINCIPAL FINDINGS Re-evaluation of a well-preserved skull of Acrocanthosaurus atokensis (NCSM 14345) provides new information regarding the palatal complex and inner surfaces of the skull and mandible. Previously inaccessible internal views and articular surfaces of nearly every element of the skull are described. Twenty-four new morphological characters are identified as variable in Allosauroidea, combined with 153 previously published characters, and evaluated for eighteen terminal taxa. Systematic analysis of this dataset recovers a single most parsimonious topology placing Acrocanthosaurus atokensis as a member of Allosauroidea, in agreement with several recent analyses that nest the taxon well within Carcharodontosauridae. CONCLUSIONS/SIGNIFICANCE A revised diagnosis of Acrocanthosaurus atokensis finds that the species is distinguished by four primary characters, including: presence of a knob on the lateral surangular shelf; enlarged posterior surangular foramen; supraoccipital protruding as a double-boss posterior to the nuchal crest; and pneumatic recess within the medial surface of the quadrate. Furthermore, the recovered phylogeny more closely agrees with the stratigraphic record than hypotheses that place Acrocanthosaurus atokensis as more closely related to Allosaurus fragilis. Fitch optimization of body size is also more consistent with the placement of Acrocanthosaurus atokensis within a clade of larger carcharodontosaurid taxa than with smaller-bodied taxa near the base of Allosauroidea. This placement of Acrocanthosaurus atokensis supports previous hypotheses of a global carcharodontosaurid radiation during the Early Cretaceous.
Collapse
Affiliation(s)
- Drew R Eddy
- Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh, North Carolina, United States of America.
| | | |
Collapse
|
29
|
The oldest modern therian mammal from Europe and its bearing on stem marsupial paleobiogeography. Proc Natl Acad Sci U S A 2009; 106:19910-5. [PMID: 19892730 DOI: 10.1073/pnas.0902940106] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We report the discovery of mammalian tribosphenic teeth from the basal Cenomanian of southwestern France that we refer to a new primitive marsupial-like form identified as a basal taxon of Marsupialiformes, a new clade recognized here to include the crown group Marsupialia and primitive stem lineages more closely related to Marsupialia than to Deltatheroida. Arcantiodelphys marchandi gen et sp nov. shares several significant marsupial-like features (s.l.) with marsupialiform taxa known from the North American Mid-Cretaceous. Among marsupialiforms, it shows a closer resemblance to Dakotadens. This resemblance, which is plesiomorphic within "tribotherians," makes Arcantiodelphys one of the most archaic known Marsupialiformes. Moreover, Arcantiodelphys is characterized by an original and precocious crushing specialization. Both the plesiomorphic and autapomorphic characteristics of Arcantiodelphys among Marsupialiformes might be explained by an Eastern origin from Asian stem metatherians, with some in situ European evolution. In addition, the presence of a mammal with North American affinities in western Europe during the early Late Cretaceous provides further evidence of a large Euramerican biogeographical province at this age or slightly before. Concerning the paleobiogeographical history of the first stem marsupialiforms during the Albian-Cenomanian interval, 2 possible dispersal routes from an Asian metatherian ancestry can be proposed: Asia to Europe via North America and Asia to North America via Europe. The main significance of the Archingeay-Les Nouillers mammal discovery is that it indicates that the beginning of the stem marsupialiforms history involved not only North America but also Europe, and that this early history in Europe remains virtually unknown.
Collapse
|
30
|
The first definitive carcharodontosaurid (Dinosauria: Theropoda) from Asia and the delayed ascent of tyrannosaurids. Naturwissenschaften 2009; 96:1051-8. [PMID: 19488730 DOI: 10.1007/s00114-009-0565-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2009] [Revised: 05/08/2009] [Accepted: 05/13/2009] [Indexed: 10/20/2022]
Abstract
Little is known about the evolution of large-bodied theropod dinosaurs during the Early to mid Cretaceous in Asia. Prior to this time, Asia was home to an endemic fauna of basal tetanurans, whereas terminal Cretaceous ecosystems were dominated by tyrannosaurids, but the intervening 60 million years left a sparse fossil record. Here, we redescribe the enigmatic large-bodied Chilantaisaurus maortuensis from the Turonian of Inner Mongolia, China. We refer this species to a new genus, Shaochilong, and analyze its systematic affinities. Although Shaochilong has previously been allied with several disparate theropod groups (Megalosauridae, Allosauridae, Tyrannosauroidea, Maniraptora), we find strong support for a derived carcharodontosaurid placement. As such, Shaochilong is the first unequivocal Asian member of Carcharodontosauridae, which was once thought to be restricted to Gondwana. The discovery of an Asian carcharodontosaurid indicates that this clade was cosmopolitan in the Early to mid Cretaceous and that Asian large-bodied theropod faunas were no longer endemic at this time. It may also suggest that the ascent of tyrannosaurids into the large-bodied dinosaurian predator niche was a late event that occurred towards the end of the Cretaceous, between the Turonian and the Campanian.
Collapse
|
31
|
Li R, Lockley MG, Makovicky PJ, Matsukawa M, Norell MA, Harris JD, Liu M. Behavioral and faunal implications of Early Cretaceous deinonychosaur trackways from China. Naturwissenschaften 2007; 95:185-91. [PMID: 17952398 DOI: 10.1007/s00114-007-0310-7] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2007] [Revised: 08/30/2007] [Accepted: 09/03/2007] [Indexed: 11/29/2022]
Abstract
Deinonychosaurian theropods, the dinosaurian sister group of birds, are characterized by a large raptorial claw borne on a highly modified second digit that was thought to be held in a retracted position during locomotion. In this study, we present new trackway evidence for two coeval deinonychosaurian taxa from the Early Cretaceous of Shandong, China that indicate a hitherto unrecognized body size diversity for this period and continent. These fossil tracks confirm diversity and locomotory patterns implied by phylogeny and biogeography, but not yet manifested in the body fossil record. Multiple parallel and closely spaced trackways generated by the larger track maker provide the best evidence yet discovered for gregarious behavior in deinonychosaurian theropods.
Collapse
Affiliation(s)
- Rihui Li
- Qingdao Institute of Marine Geology, China Geological Survey, Qingdao 266071, People's Republic of China.
| | | | | | | | | | | | | |
Collapse
|
32
|
|
33
|
Case JA, Goin FJ, Woodburne MO. “South American” Marsupials from the Late Cretaceous of North America and the Origin of Marsupial Cohorts. J MAMM EVOL 2005. [DOI: 10.1007/s10914-005-7329-3] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
34
|
HU YAOMING, FOX RICHARDC, WANG YUANQING, LI CHUANKUI. A New Spalacotheriid Symmetrodont from the Early Cretaceous of Northeastern China. AMERICAN MUSEUM NOVITATES 2005. [DOI: 10.1206/0003-0082(2005)475[0001:anssft]2.0.co;2] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
|
35
|
CIFELLI RICHARDL. Chapter 5: Marsupial Mammals from the Albian–Cenomanian (Early–Late Cretaceous) Boundary, Utah. BULLETIN OF THE AMERICAN MUSEUM OF NATURAL HISTORY 2004. [DOI: 10.1206/0003-0090(2004)285<0062:c>2.0.co;2] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
|
36
|
Abstract
The ascendancy of dinosaurs on land near the close of the Triassic now appears to have been as accidental and opportunistic as their demise and replacement by therian mammals at the end of the Cretaceous. The dinosaurian radiation, launched by 1-meter-long bipeds, was slower in tempo and more restricted in adaptive scope than that of therian mammals. A notable exception was the evolution of birds from small-bodied predatory dinosaurs, which involved a dramatic decrease in body size. Recurring phylogenetic trends among dinosaurs include, to the contrary, increase in body size. There is no evidence for co-evolution between predators and prey or between herbivores and flowering plants. As the major land masses drifted apart, dinosaurian biogeography was molded more by regional extinction and intercontinental dispersal than by the breakup sequence of Pangaea.
Collapse
Affiliation(s)
- P C Sereno
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637, USA
| |
Collapse
|
37
|
Rogers SW. Exploring dinosaur neuropaleobiology: viewpoint computed tomography scanning and analysis of an Allosaurus fragilis endocast. Neuron 1998; 21:673-9. [PMID: 9808455 DOI: 10.1016/s0896-6273(00)80585-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The unique opportunity to examine an exceptionally well-preserved natural endocranial cast (endocast) from a carnivorous dinosaur of the late Jurassic period, Allosaurus fragilis, was afforded this neurobiologist. The endocast exhibits numerous surface features including the complete vestibular apparatus. Spiral computed tomography scanning revealed multiple internal features including putative blood vessels, connective tissue-like arrays, and a prominent symmetrical density consistent with the putative brain or its cast. The evidence suggests that this organism's neurobiology resembled closely that of modern crocodylian species and should be included for consideration when examining ideas of Allosaurus evolution, behavior, and eventual extinction.
Collapse
Affiliation(s)
- S W Rogers
- Salt Lake City Veteran's Affairs Medical Center, Department of Neurobiology and Anatomy, University of Utah 84112, USA.
| |
Collapse
|