Ornithopoda Overview
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Questions and Answers

What is a distinguishing feature of Oryctodromeus?

  • It had a long neck for reaching high vegetation.
  • It was primarily a carnivorous species.
  • It is known for its swimming abilities.
  • It was the first dinosaur to show burrowing and denning behavior. (correct)

    • Why is the systematics of basal ornithopods considered volatile?

  • Many species are well-preserved and abundant.
  • Taxa are often known only from complete skeletons.
  • There are no fossil records available from this period.
  • Fragmentary specimens can closely resemble one another. (correct)

    • What time period do Oryctodromeus and other ornithopods generally belong to?

  • Triassic Period
  • Jurassic Period
  • Early to Late Cretaceous Period (correct)
  • Paleocene Epoch

    • What can be inferred about Basal Iguanodontoidea and Hadrosauridae based on their classification?

    <p>They are both part of the Ornithopoda clade.</p> Signup and view all the answers

    What is the significance of Burianosaurus augustai's discovery?

    <p>It is known from only a single femur.</p> Signup and view all the answers

    What is the significance of Yandusaurus in the context of Ornithopoda?

    <p>It is the oldest ornithopod fossil.</p> Signup and view all the answers

    What distinguishes basal ornithopods from euornithopods?

    <p>Basal ornithopods have four hoofed-toes, while euornithopods have three functional hoofed-toes.</p> Signup and view all the answers

    Which of the following statements is true about the size of ornithopods?

    <p>Ornithopods ranged from approximately 2 to 14 meters in length.</p> Signup and view all the answers

    What evolutionary period is associated with the emergence of Ornithopoda?

    <p>Early Jurassic.</p> Signup and view all the answers

    Which of the following taxa is classified as a basal ornithopod?

    <p>Hypsilophodon.</p> Signup and view all the answers

    What is a defining feature of Lambeosaurinae hadrosaurids?

    <p>Hollow-crested cranial structure</p> Signup and view all the answers

    How many individual teeth can the dental battery of hadrosaurids contain?

    <p>Up to 1400</p> Signup and view all the answers

    What distinguishes hadrosaurid teeth from those of other vertebrates?

    <p>They comprise six different dental tissues.</p> Signup and view all the answers

    Which of the following features is NOT associated with hadrosaurids?

    <p>Solid-crested cranial structure</p> Signup and view all the answers

    During which geological period did hadrosaurids exclusively exist?

    <p>Late Cretaceous</p> Signup and view all the answers

    How do hadrosaurids achieve continuous grinding of food?

    <p>Using their grinding dental battery</p> Signup and view all the answers

    What is the function of replacement teeth in hadrosaurids?

    <p>To continuously push out old teeth</p> Signup and view all the answers

    How does the complexity of hadrosaurid teeth compare to that of mammals?

    <p>Hadrosaurid teeth are more complex than all mammals.</p> Signup and view all the answers

    What characteristic is NOT associated with Iguanodontoidea?

    <p>Short, narrow snouts</p> Signup and view all the answers

    Which of the following statements about Tenontosaurus is true?

    <p>It is one of the most common dinosaurs in the Early Cretaceous.</p> Signup and view all the answers

    What is a distinguishing feature of Hadrosauridae?

    <p>'Duck bill' formed by premaxilla and predentary</p> Signup and view all the answers

    How long could Iguanodon grow?

    <p>Approximately 10 m</p> Signup and view all the answers

    What ecological role did Hadrosauridae play in their environment?

    <p>They were dominant large herbivores.</p> Signup and view all the answers

    What evidence suggests social behavior among Iguanodon?

    <p>Multiple individuals found in a coal mine</p> Signup and view all the answers

    Which dinosaur is associated with having a toothless premaxilla?

    <p>Ouranosaurus</p> Signup and view all the answers

    Deinonychus is suggested to have engaged in what kind of hunting behavior?

    <p>Pack hunting with Tenontosaurus</p> Signup and view all the answers

    The term 'unguals' refers to which part of the Iguanodontia?

    <p>Toes or claws</p> Signup and view all the answers

    Which feature is unique to the Hadrosauridae family?

    <p>Complex dental structures for grinding</p> Signup and view all the answers

    What describes the likely social behavior of hadrosaurs during the Late Cretaceous?

    <p>They likely moved in large herds.</p> Signup and view all the answers

    What type of evidence supports the idea of social behavior in hadrosaurs?

    <p>Monodominant hadrosaur bonebeds.</p> Signup and view all the answers

    What is a significant characteristic of hadrosaur jaws?

    <p>Maximized energy from plant resources.</p> Signup and view all the answers

    What does the evidence suggest about the breeding behavior of derived ornithopods like hadrosaurs?

    <p>They reused nesting sites for multiple generations.</p> Signup and view all the answers

    What is indicated by the presence of large subadult and adult-sized bones in hadrosaur bonebeds?

    <p>Strong evidence for sociality and community living.</p> Signup and view all the answers

    Which hadrosaur species is mentioned as having evidence of child-rearing behaviors?

    <p>Maiasaura.</p> Signup and view all the answers

    How many disarticulated elements have been found in some hadrosaur bonebeds?

    <p>More than 10,000.</p> Signup and view all the answers

    What type of biomechanical process was maximally efficient in hadrosaurs?

    <p>Energy extraction from plant material.</p> Signup and view all the answers

    Study Notes

    Ornithopoda

    • Oldest fossil: Yandusaurus (Middle Jurassic)
    • Survived until the end of the Cretaceous
    • Known from all continents
    • Size range: 2 to 14 m in length
    • Basal members: Agile bipeds
    • Large derived forms: Mostly quadrupedal
    • Basal ornithopods (non-euornithopods): 4 hoofed-toes for weight support
    • Euornithopoda: 3 functional hoofed-toes
    • Systematics of basal ornithopods and ornithischians is volatile due to fragmentary specimens and similar morphology

    Basal Ornithopods

    • Burianosaurus augustai: Cenomanian of the Czech Republic, known from one femur

    Orodrominae

    • Early to Late Cretaceous, NA & Asia
    • Oryctodromeus: First dinosaur to show burrowing and denning behavior
    • An adult and two juveniles found in a den
    • Bipedal with forelimbs adapted for digging

    Basal Iguanodontians

    • Tenontosaurus: Common dinosaur in the Early Cretaceous of western NA
    • 75% of Tenontosaurus localities contain Deinonychus remains, suggesting pack hunting

    Iguanodontoidea

    • Longer, broader snouts
    • Larger size
    • Thumb spike (digit I)
    • Digit V opposable
    • Digits II & III robust with large, rounded, weight-bearing unguals

    Iguanodontoidea: Basal Iguanodontoideans

    • Iguanodon: Early Cretaceous, Europe; adults up to 10 m, ~3 tons
    • Named in 1825 by Gideon Mantell
    • 38 skeletons from a Belgian Coal mine
    • 15 individuals from a bonebed in Germany: Evidence for sociality
    • Forelimbs ~75% the size of hindlimbs

    Iguanodontoidea: Basal Iguanodontoideans

    • Ouranosaurus: Early Cretaceous, Niger; ~8 m in length, ~4 tons
    • Toothless premaxilla; one row of replacement teeth
    • Small crest in front of the skull
    • Tall neural spines

    Hadrosauridae

    • Cretaceous; globally distributed
    • Larger size: > 14 m in length (Shantungosaurus)
    • Bipedal and quadrupedal capability
    • Dominant mode: Quadrupedal
    • "Duck bill" is a flaring of the premaxilla and predentary covered by a keratin-covered beak (rhamphotheca)
    • Evidence for gregariousness and herding behavior

    Hadrosauridae

    • Two major clades: Hadrosaurinae and Lambeosaurinae
    • Up to 15 m in length; 2 m skulls
    • Exclusively Late Cretaceous in age

    Hadrosauridae: Hadrosaurinae

    • "Solid-crested"

    Hadrosauridae: Lambeosaurinae

    • "Hollow-crested"
    • Cranial crest formed by the nasal bone
    • Tall, symmetrical lancelet tooth
    • Dental battery with three or more teeth

    Hadrosaurids vs. Basal Iguanodontia

    • Further expansion of the snout ("duck bill")
    • Increase in the number of tooth positions
    • Grinding dental battery with a continuous grinding surface
    • Teeth with greater structural complexity

    Hadrosauridae: Dentition

    • Up to 1400 diamond-shaped, tightly packed teeth
    • 5 replacement teeth constantly pushing

    Hadrosauridae: Dental Histology

    • Each tooth is comprised of at least 6 different dental tissues
    • More complex than teeth of mammals, including horses
    • Sophisticated dental system

    Hadrosauridae: Abundance

    • Most abundant dinosaurs in the Late Cretaceous of NA
    • Moved in large herds
    • Efficient jaws maximized energy from plant resources

    Hadrosauridae: Social Behaviour (Bonebeds)

    • Monodominant hadrosaur bonebeds are known from NA and Asia
    • Dozens of Edmontosaurus bonebeds from the L Campanian and Maastrichtian of Canada and the US
    • Some preserved >10,000 disarticulated elements
    • Large subadults and adult-sized bones dominate
    • Evidence for social and/or herding behavior

    Hadrosauridae: Reproduction

    • Not much evidence from basal ornithopods
    • Derived ornithopods (Hadrosauridae) show evidence of child-rearing and parental care (e.g., Maiasaura, Hypacrosaurus)
    • Nesting sites reused for multiple generations
    • Evidence for 1 and 2 year juvenile cohorts

    Hadrosauridae: Reproduction (Hypacrosaurus)

    • Hypacrosaurus Nesting Site at Devil's Coulee, AB

    Hadrosauridae: Soft Tissue Preservation

    • Edmontosaurus regalis (L. Cret)

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    Lecture 14 - Ornithopoda, Fall 2024 - PDF

    Description

    Explore the fascinating world of Ornithopoda, a group of dinosaurs that thrived from the Middle Jurassic to the end of the Cretaceous. This quiz covers key fossil findings, systematic challenges, and notable species such as Yandusaurus and Oryctodromeus. Discover their adaptations for survival and the evolution of their morphology.

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