Studied by 100 peopleWhich of the two clades of Dinosauria do theropods belong to?
Saurischia
Describe the characteristics of the Saurischian clade.
-Blade like serrated teeth -Promaxillary fenestra -Intramandibular joint -Enlarged hands with increased grasping ability -Bipedal -Bird-like feet -Lightly built theropod skulls -Feathers -Pneumatic bones
When did pterosaurs originate?
Late Triassic
When did Pterosaurs go extinct?
End of Cretaceous
What are key characteristics of the Pterodactyloid?
Mono-fenestra (fused external nares and ante-orbital fenestra), short tail, no teeth (beaks)
What are key characteristics of the Rhamphorhycoid?
Long tail, teeth
Which is paraphyletic; Pterodactyloid or Ramphorhycoid?
Rhamphorhynchoid, does not include all descendants
What environments are most Pterosaurs preserved in?
marine/lacustrine environments; fine grained sediments preserve soft tissue
Why are most Pterosaur bones crushed flat?
Hollow, pneumatic bones
Can you draw a cladogram showing the relationships in Archosauria between crocodylomorphs, pterosaurs, and dinosaurs?
Archosauria: Nests with vegetation; parental care of young; extensive vocal communication; parasagittal stance?; flow-through lung?
Crocodylomorphs: part of Pseudosuchia; enlarged calcanea tuber ("heel"); two rows of dorsal osteoderms
Pterosaurs: part of Ornithodira; cervicals distinct from dorsals; elongate tibiae and metatarsi; ? loss of boy armor
Dinosaurs: part of Dinosauromorpha; parasagittal stance? Hinge-like ankle joint AND Dracohors; elongate pubes and ischia
(picture of chart can be found on study guide)
How is Herrerasaurus related to Theropods?
One of the most primitive dinosaurs
Caused Saurischian and Ornithischian clades to split
Was originally thought to be a theropod but does not contain all of its features/evolutionary novelties
What are the features that are diagnostic of the theropods?
Blade like serrated teeth
promaxillary fenestra
intramandibular joint (extra joint in lower jaw, allows motion)
enlarged hands with increased grasping ability
Tyrannosaurus, Velociraptor, Allosaurus
Many were feathered
Bird like feet
Enlarged hand with pinky, 4 or 3 fingers with sharp claws, grasping hands with large claws
Theropod skulls are lightly built
Based on the features that are diagnostic of the theropods, what types of behavior can be inferred?
Bird like Predatory All bipedal
What are the bird-like features of theropods?
Head-neck joint (theropod skull was attached to the neck at a highly mobile joint), had bird-like feet, tail: changes midway from flexible proximally to being stiff distally, hollow, and light bones-kept the skeleton light and bones from bending
Which clade of theropods is most closely related to birds and what features do birds and this clade share?
Coelurosauria
Enlarged brains, Tridactyl hand with long second and third digit, feathers, hinge-like ankles
What is the major function of the furcula?
Fused collar bones
To strengthen skeleton and hold wings
Which theropods are known to be feathered and had wings?
Archaeopteryx Insulation and/or display
What was the function of the wings in non-flying taxa?
insulation or display
How are ceratosaurs distinguished from other theropods?
Six or more sacral vertebrae
very deep coracoids
small forelimbs
very small, maybe nonfunctional
What are the distinguishing features of carnosaurs?
Feathers
Extra opening in maxillary
very large nasal bones
What are the distinguishing features of coelurosaurs?
most bird like dinosaur
enlarged brains
Tridactyl hands with long second and third digit
boat shaped chevron bones
feathers
What are the unusual features of enigmatic coelurosaurs, such as oviraptorids and therizinosaurs?
Therizinosaurs: Small skulls Long necks Huge Claws Short legs
Oviraptorids: Toothless jaws Short snouts Boxy skulls Large fenestra in mandible Crest of sponge-like bone on tip of snout
Using Plateosaurus as a representative prosauropod review the main characters of the group.
-Small teeth with large serrations -Elongated necks (feeding over wide arc) -Jaw articulation offset-all teeth occluded simultaneously -Poorly pneumatized vertebrae
What anatomical evidence supports the notion that prosauropods were plant-eaters?
Long necks that feed over a wide arc side to side
Jaw hinge below upper tooth row
Offset of jaws allowed parallel tooth rows to come in contact simultaneously
spatulate teeth, serrated
gizzard (small stones found in stomach to crush vegetation)
Explain why most paleontologists exclude any known prosauropod from the ancestry of sauropods.
Because theropods are ancestors to sauropods, but they're distinguished enough that they have been given their own clade
What are the two sauropodomorph groups?
Prosaurapoda and Sauropoda
What are the features that distinguish Prosaurapoda and Sauropoda from other dinosaurs?
very large; peg shaped teeth; teeth only in front; external nares pushed back on skull; long neck--pneumatic bones offset weight; oval/oblong leg bone cross section (lateral stress); lower jaw "hinge" (greater mechanical advantage when chewing)
Why are vertebrae in the shoulder region the most widely used diagnostic element in sauropod classification?
fragile skulls easily lost/destroyed after death so we can't rely on the skulls to classify species; intricate vertebrae vary great between sauropods
Compare and contrast the skulls of diplodocid, camarasaurid, and brachiosauri sauropods.
Diplodocus: only teeth in front and possibly a beak
Camarasaurus: rounded nose unlike Brachiosaurus that has a scooping nose
Brachiosaurus: enlarged nostrils above the eye, backwards L shape, dip in pre-maxilla
Shunosaurus: teeth facing forward, no dip in pre-maxilla like the brachiosaurus
How did the confusion about the name Brontosaurus resolve?
principle of priority (first name given is the name used)
What are the possible mechanisms for the development of long sauropod necks?
Robbing vertebrae from the back
Move shoulders back so dorsal vertebrae become cervical vertebrae
Adding extra vertebrae (happens only in early embryonic developmental)
Elongating individual vertebrae
What saurischian characteristics allowed sauropods to develop the longest necks of any vertebrates in the history of the earth?
Long neck: -allows feeding over wide arc (side to side) -are so long because vertebrae are so light (pneumatic)
Methods of Development: -robbing vertebrae from the back -move shoulders back so dorsal vertebrae become cervical vertebrae -adding extra vertebrae (happens only in early embryonic development) -elongating individual vertebrae
What is the significance of pneumatic vertebrae and their effect on the structure of the vertebrae in sauropods?
Added air so necks were lighter,
What is the relationship between skull size and neck length in sauropods?
Smaller skulls = Longer necks
What is the evidence that suggest diplodocids could not raise their heads above the shoulders?
Necks were straight but were angled down, necks weren't super flexible-only side to side motions
Compare and contrast the feeding strategies of grazers vs high browsers.
grazers, wide jaws, lots of food at once
browsers, more narrow jaws, "picky" eaters
When did ornithischian live and describe their distinguishing characteristics?
-lived: longest lived dinosaur, middle jurassic to end of cretaceous
-self sharpening teeth -feathers -scales -cheeks
What are dental batteries?
teeth stacked on each other on sockets
How do dental batteries function?
dinosaurs grow and replace teeth throughout their entire lives, they are constantly replaced by these dental batteries.
What groups posses dental batteries?
sauropods, hadrosaurs, and ceratopsians, ornithischians
How did dental batteries allow ornithischians to be successful?
Constantly had new teeth, losing them wasn't a big deal, got worn down by chewing.
Which clade is first in Theropod phylogeny?
Ceratosauria
What was the main function of feathers on theropods?
Display
Which is among the most primitive theropods? Staurikosaurus Dimetrodon Allosaurus Herrerasaurus
Staurikosaurus Herrerasaurus
Which clade is characterized by highly pneumatic (light) vertebrae, and primitive feathers?
Coelurosauria
Which clade is characterized by four fingered hands with sharp claws on first 3 digits?
Ceratosauria
Which clade is characterized by foramen in eye socket bone, and low spines at base of neck?
Carnosauria
Which clade includes primitive theropods, like Dilophosaurus?
Ceratosauria
Which is NOT a characteristic of Therizinosauria?
large teeth
What is true about Sauropods?
-Have air-filled (pneumatic vertebrae) -Includes Camerasaurus -long neck giants -have VERY fragile skulls
What is FALSE about Prosauropods?
They are a monophyletic group.
What is a similarity of Prosauropods and Sauropods?
They are both clades of Sauropodomorphia
Why do paleontologists need permits to search for and collect vertebrate fossils on federal and state-owned lands?
-"keeps ya out of jail and out of trouble"-Brooks
-Helps protects the bones and know if there are bones of significance
What are the benefits of digital extraction of bones using CAT scanning vs mechanical bone extraction?
CAT scanning: -high resolution -put bones still inside of rock -doesn't destroy specimen if you mess up the scan -minute detail
Mechanical extraction:
What are the basic rules of naming animals? (It is the same for dinosaurs as it is for all other animals)
Whoever describes it in a technical jounral gets to name it first; genus must be unique, species can repeat;
What is the difference between taxonomic lumpers and splitters?
Taxonomic lumpers: groups several genera/species into one
Splitters: Think most discoveries are a new species
Why do many paleontologists end up teaching human anatomy at universities and medical schools?
few universities "need" a paleontologist, but they all need someone to teach pre-med or med-students anatomy
What is the paleoenvironment of the Saints and Sinners Quarry (Stratigraphic context)?
-Nugget Sandstone -Based on radiometrically dated rock layers above and below the Nugget sandstone
What is the paleoenvironment of the Saints and Sinners Quarry (depositional environment)?
-Oasis in a vast desert, animals died during drought, bones in shallow water of oasis (buried by sand blown into lake)
What is age of the paleoenvironment of the Saints and Sinners Quarry
-Late Triassic and Early Jurassic (210 million years ago) -based on Drepanosaurid and Procolophonid
True or false? Teeth of Diplodocidae are peg like.
True
True or false? Teeth of Camerasaurus are spoon shaped.
True
True or false? Sauropods necks elongate through the addition of vertebrae as ADULTS.
False
What is the use of long necks?
Feeding widely side to side
Besides their pelvic structure, what distinguishes Ornithischia?
Predentary bone
What is the evolutionary novelty distinguishing Neornithischia is?
Teeth with more enamel on one side than the other
What is the feature of multiple teeth stacked vertically and side-by-side?
Dental batteries
Which is a clade of Ornithischian dinosaurs? Theropods Sauropods Ornithopods Thyreophorans
Ornithopods Thyreophorans
Which is NOT a characteristic of Ornithopods? Predentary Omnivores Cheeks Dental Batteries
Omnivores
What about dental batteries contributed to the success of Ornithopods?
Allow them to process much fibrous vegetation.
What are the three middle Iguanodon digits used for?
Walking
What is the fifth Iguanodon digit (pinky) used for?
Grasping
What is the first Iguanodon digit (thumb) used for?
Defense
Which is characterized by large size, toothless beaks, dental batteries, and no thumb? Iguanodontids Hadosaurids Diplodicae Hypsilophodontidae
Hadrosaurids
Hadrosauirids, "duck billed" ornithopods, contain two main variations:
Hadrosaurines and Lambeosaurines
Which is characterized by tubes and crests on their heads? Hadrosaurines Lambeosaurines
Lambeosaurines
What is the purpose of Lambeosaurines crests?
Display Honking/Vocalizing
The diastema between the hadrosaur's beak and teeth provide evidence that?
The tongue could have been used to manipulate food
What does the additional joints in Hadrosaurs skulls provide evidence of?
They may have been able to move their jaws side to side
What evolutionary novelty distinguishes the Thyreophorans?
Boney plates in their skin (dermal ossicles)
What are the two clades of Thyreophorans?
Stegosauria Ankylosauria
What are the evolutionary novelties that distinguish Stegosaurs?
Rows of large plates on back
True or false? Dermal ossicles were solid?
False
What filled dermal ossicle holes?
blood vessels
What is the difference between Ankylosaurids and Nodosaurid Ankylosaurs?
Nodosaurs have elongate snouts and no club on tail
What clade of Ornithischia is large headed and often horned?
Marginocephalia
Marginocephalia include
Ceratopsians and Pachycephalosaurs
Which is NOT true of Pachycephalosauria?
Divided into domed and non-domed
What do we now believe about non-domed Pachycephalosauria?
They are young juveniles
What does the image of damaged domes tell us about Pachycephalosauria?
Damage due to head butting
Which is NOT true of Ceratopsians?
They have dermal ossicles
What are the two main clades of Ceratopsidae?
Ceratopsinae Centrosaurinae
Which is TRUE of Centrosaurinae (Pachyrinosaurinae) Ex. Pachyrhinosaurus?
Short face Long nasal horn
Which is TRUE of Ceratopsinae (Chasmosaurinae) (ex. Triceratops)
Long face Short nasal horn
Large bone assemblages of thousands of Ceratopsians tells us?
They traveled in herds
What caused the very backwards bent neck of a dinosaur skeleton?
Ligaments pulled the body into this pose after death
The animal was floating in water
Which describes bones that are in place when they are found?
Articulated
Which describes Continental Drift?
The continents were once together and have since drifted apart
What was a major concern of Continental Drift?
Wegener did not have evidence of a mechanism for movement
What event lead to the development of Plate Tectonics?
Mapping the sea floor topography
Note
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