dinosaurs final exam

Explain what causes plate tectonics, including the primary driving force.

Density drives plate movement
Plate movement: Density (thermal) differences
Sinking edges of oceanic plates
Denser things sink, lighter things float

Know the evidence supporting plate tectonics.

How is Climate Affected (Evidence of Plate Tectonics)
Fragmenting or coalescing continents
Size of continents
Latitude
Mountain ranges
Epicontinental seas, etc.

Know how plate tectonics impacts evolution and extinction.

Evolution
Spread then throughout the world
Small continents tend to be more humid and moist
Affects the environment, and environment drives evolution
Splitting up gene pools
Creation of new environments
Preventing/facilitating migration

Extinction
Violent Volcanoes
Earthquakes

Know the primary control on sea level.

What is the relationship between seafloor spreading rates and sea level?
In the Late Cretaceous, sea level was at an all time high. What does this reveal about the rate of plate movement?
North American Interior Seaway separates North America
Late Cretaceous world (90 Ma)
Plate movement

Describe the evolution of plants through time.

Plants
Plants likely played a major role in dinosaur evolution


1. Gymnosperms until they became almost extinct and Angiosperms became prevalent-changed the dinosaurs diet. 

Explain the limitations of reproduction by spores.

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They lack seeds or flowers, and require water for reproduction, efficiency of pollination.

Reproduced by spores. They lack seed or flowers. Require water for reproduction They occupy a range of habitats Australian Ferns Pteridophyta -Ferns Tree ferns in New Zealand Underside of a fertile frond showing sori. Soria contains capsules called sporangia. These capsules contain spores.Schematic sporangia, releasing spores

Identify examples of gymnosperms and angiosperms.

Gymnosperms

Ginkgo, cycads, conifers

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angiosperms

any flowering plant, grasses, fruit trees

Know the major groups of vertebrates that made their first appearance in the Late Triassic.

Dinosaurs, pterosaurs, turtles, mammals

Know which major groups of dinosaurs dominated each of the three epochs of the Mesozoic.

Triassic: Basal ornithischians, prosauropods, coelophysis, Some small dinosaurs but mainly dominated by reptiles and amphibians (crocodylomorphs), Herrerasaurus

Jurassic: Sauropods, Stegosaurids, small to medium ornithopods. Dinosaurs dominated this epoch. Most notably the very large herbivorous Sauropods, large Stegosaurids, Hypsilophodontids, and Allosaurids

Cretaceous: large ornithopods, ankylosaurs, sauropods, theropods. Dominated mostly by hadrosaurs, certopsians, ankylosaurs, coelurosaurs, and turannosaurids 

Explain why teeth provide most of the Mesozoic record of mammals and why the teeth are so useful identifying species.

They’re the one part that is found relatively often, so we are able to map out who’s who using the teeth that we find in the fossil record

Describe the major changes in vegetation and how these changes might have influenced dinosaur evolution.

Angiosperms came and took over the scene, spreading like wildfire all over the place. This made it advantageous to be an herbivore, so those with dental batteries did better than those who didn’t. Thus we see the success of herbivores skyrocket as these plants spread

Describe the changes in dinosaurian faunas during the time of the appearance of angiosperms and explain the significance.

Angiosperms took over the gymnosperm and became the dominant plant. This is also when ornithopods were a big thing, so they provided food for them

Explain why it is unlikely that cycads were primary food for herbivorous dinosaurs based on our knowledge of extant cycads.

The seeds are poisonous, so eating them would be a not good time


1. Many are toxic, leaves are hard with little nutritional value, and seeds harbor bacteria that produce toxic compounds. 

Know when dinosaurs became the dominant terrestrial vertebrates and when the non-avian dinosaurs went extinct.

Became dominant in the Early and Middle Jurrassic (201-163 mya)
Late Cretaceous

Define a dinosaur trace fossil and give examples.

Tracks, burrows, feeding marks, nests, chemical traces, coprolites/feces

Explain the function of gastroliths and know which dinosaurs have been found with these stones.

Stones dinosaurs ate to help with digestion
Herbivores did this, found in sauropod dinosaurs

Know the origin of the “human” footprints found primarily in Early Cretaceous rocks in Texas.

Carved by a person, not a real human footprint

Know what types of nests are made by dinosaurs and what the arrangement of eggs reveals.

Eggs laid in rows
Eggs laid in circles
Always laid in pairs, shows they lay 2 eggs at a time, have TWO ovaries instead of one like birds

Know the evidence for group behavior among dinosaurs

Display structures (ex: crests used for display)
Sexual dimorphism
Change in shape during growth
Multiple dino fossils in bone beds
Nesting behavior
Multiple trackways

Define the following terms: endothermic, exothermic, poikiolothermic, and homeothermic.
Know whether Maiasaura endothermic or ectothermic and the evidence that supports this.

Ectothermic
Low metabolic rate
External sources of head
Advantages
Not as much to feed self
Shut down for multiple months
Disadvantages
Low stamina

Endothermic
High metabolic rate
Internal heat source
Advantages
Don’t rely on the sun to live
Better stamina - farther and faster when running
Disadvantages
A lot more food needed

Homeothermic
Tightly regulated body temperature

Poikilothermic
Fluctuating body temperature

Exceptions for general rules

Explain the relationship between body temperature strategies and posture

Erect posture
Needs more energy to move (compared to sprawling)
Indicate they had stamina and speed

Explain the relationship between body temperature strategies and metabolism

Feeding adaptations
Dental batteries
Time and energy chewing
Needs energy
Endothermic bc then they don’t need to rely on the sun
Swallow it down quick
Don’t need as much time or energy

Explain the relationship between body temperature strategies and blood pressure

Blood pressure
Birds and mammals have high blood pressure = endothermic
Amphibians & reptiles have low blood pressure = ectothermic
Dinos had high blood pressure = evidence they were endothermic

Explain the relationship between body temperature strategies and weight

Smaller mammals lose heat faster, while bigger mammals keep their heat longer

Explain the relationship between body temperature strategies and predator-prey ratios

Predator Prey ratio
If you need to eat a lot bc you need a lot of energy (endothermic), then there can’t be a lot of you bc you’ll eat all of the meals you need to survive
A lot of work and calculations…
Low predator to prey ratio
Not as many carnivores as omni/herbivores

Explain the relationship between body temperature strategies and bone microstructure

Bone Histology - microstructure
Cannot tell if an animal is an endotherm or exotherm

Explain the relationship between body temperature strategies and social behavior

Social Behavior
Brooding (birds & mammals) = Endothermic
Altricial - can’t leave the nest immediately/rely on parents through young life
Precocial - leaves the nest/parents almost immediately
Tracks all together/big bone beds - dinos are in a herd - social
Need a lot of energy
Most likely endotherms
Velociraptor & Protoceratops
Lived together/same environment
Predator/prey relationship?
If velociraptor is failing 9 times out of 10 to kill their prey, we should see some healing on the protoceratops bones
Fighting dinosaurs
Velociraptor fighting protoceratops in fossil record

Explain the relationship between body temperature strategies and geographic distribution

Birds & mammals everywhere = endotherms
Amphibians and reptiles found closer to the equator = ectotherms
Dinos are also found everywhere = endotherms

Explain the relationship between body temperature strategies and isotopic evidence

Isotopic Evidence
Dinos had similar isotopic levels throughout the day
Kept their body temperature the same
Dinos are homeothermic endotherms

nasal turbinates

Allows us to breath while chewing
Warming air going in, and cooling air going out
See in mammals
Not in crocodiles
Dinos do not have nasal turbinates
Maybe there is another way to warm up and cool down?

genealogy - dino to bird

What does the relationships between dinos, crocs, and birds suggest about theropod (and dinosaur) metabolism?
Birds are endotherms
But crocs are ectotherms?
Are dinos in the middle, or endotherms?
Avian thermal features
Avian style lungs
Go in one way, go out another way
Dinos had these efficient lungs
Air filled vertebrae and other bones
Air sacks make bones light and air filled
Dinos used it for
Effective locomotion
And endotherm
Scales and feathers on birds
Feathers are a shared trait of all dinos & some just lost the trait
Down feathers could help with thermoregulation
Trying to keep an internal body temp = endotherms

blood pressure and heat

Dinos had imperfect 4 chambered hearts or fully formed 4 chambered hearts?
Could’ve gone from imperfect to fully formed through the evolution process

growth rate

Rapid in theropods and hadrosaurs
40ft in 18 years - T-rex
Need to put on a lot of weight
Need a lot of energy
endothermic
Didn’t live long
Gigantothermy
Animals of large sizes take a long time to cool off, so it is heat loss that is the problem
Study showed:
Long neck - food w minimal effort
Small head - only possible bc they didn’t chew
Avian-like lungs - light body/bones
Warm-blooded - grew to sexual maturity quickly
Egg laying - produced large number of (precocial) young
Therefore: advantages of endothermy without usual limitations

Know the general consensus for dinosaurian metabolic strategies.

Some dinos were endothermic while others were ectothermic
Metabolically diverse
Theropods & ornithopods endothermic
Others perhaps ectotherms
Mixture
Large, adult, dinos gigantotherms (inertial thermic)
Small - ectothermic, endothermic

Know which groups were likely the most active and had high metabolic rates.

Theropods and ornithopods

Know the surface-area-to-volume relationship between large dinosaurs and small dinosaurs.
Know the general size of Velociraptor:

3 ft tall, about the size of a big dog

Describe the history of flight in birds and other animals.

Bats and insects were early flyers

Know which species were first to gain flight.

Insects were the first animals to attain powered flight

Explain the significance of Microraptor and Anchiornis as they relate to probable origins of flight among dinosaurs.

Microraptor was found with four wings

Explain (1) the “ground up” and “tree down” hypotheses for the origin of flight in birds/dinosaurs and (2) which theory is best supported by new feathered dinosaur findings.

Tree down: started jumping from trees, then gliding, then flying
Ground up: Running along ground, use wings to bat down incest and try to eat them, then evolve to flying
Display: hopping around, showing off, turned to flying off the ground

Know the features attributed to flight and in which clade these avian features originated.

Vaned feathers
Maniraptora

Wings
Paraves

Pygostyle (fused tail)
Pygostylia

Keeled sternum
ornithothoraces

Know which clade of dinosaurs feathers are found.

Theropods

Know the original purpose and function of feathers, and where they were located in feathered theropods.

Insulation
Display
Then flight

Explain why the status of “bird” in Archaeopteryx is now being questioned.

Richard Owens claimed it was a bird
Thomas Huxley said birds were related to therapod dinos
Franz Nopcsa thought birds were from a completely different link of animals, but not sure where
Heilmann - “the origin of birds”
Rejected bird/dino relationship
Claimed dinos had no furcula
He was wrong, but we didn’t know it at first
We are unsure where the clade actually belongs
Because of all the features it has
We’ve found some after the first one without any feathers in the fossil
If this one was found first, it wouldve been classified as a dino
Found london specimen with wings & many feathers
Arachaeoperyx is identified as a bird, only because it had feathers
Otherwise it would have been classified as a theropod dino

Know the ages of Archaeopteryx, where it was originally found, and its significance to evolution.

1860 - found a Late Jurassic feather in Germany
Interpreted as evidence of Late Jurassic birds
Year later, found an articulate fossil of the archaeopteryx
Realized there were birds -- but it was just a dino

bird variation

Over 10,000 species of birds
1/10th ounce gram hummingbird to 300 lb ostrich

Features in birds and dinos

Pneumatic bones
Furcula
Feathers
Pubis in the archaeopteryx is angled back
Birds of prey will use their second digit claw to hold their prey down while tearing it apart with their beak

Explain why most hypotheses for the extinction of the non-avian dinosaurs, with the exception of two, are unlikely and are little considered in the textbook and elsewhere.

Extinction Hypothesis - What has been proposed
Sample List Extinction Hypotheses
Climate change
Tied to withdrawal of epicontinental seas)
Seas in K were 300’ higher than today
Extensive volcanism
Disease
Increase in solar radiation
Radiation from nearby supernova
Extraterrestrial bolide impact
Many others
Three Viable Hypothesis
Climate change
Largely tied to dramatic drop in sea level
Deccan Traps (stairs) - Large Volcanic Event in India
Input of gasses, including CO2 and sulfur into atmosphere
Possibly related to cooling climate @ end of Cretaceous
Eruption spanned - 68-60 Ma ago (Late K to Paleocene)
Most of 66 Ma
Impact (or impacts) of meteor or comet
Dust in atmosphere shut down photosynthesis
Base of food chain disrupted (plants, plankton)
Devastation of marine and terrestrial environments

Know the definition of a mass extinction, when the largest occurred, and when non-avian dinosaurs went extinct.

Mass extinction definition:
Above background rate of ongoing and omnipresent extinction
Generally defined as the extinction of at least 50% of species in geologically short period of time
When the largest occurred
Permian-Triassic Extinction
Largest known extinction
252 million years ago
96% marine and 70% of terrestrial species lost
Caused by?
Extensive volcanism
Climate change
Impacts
Increase in greenhouse gasses
Anoxia (oxygen depletion of oceans)
Cause remains unknown
When non-avian dinosaurs went extinct
End Cretaceous, K-T, Extinction
Age of the event?
66 Ma

Know what major groups of animals were affected by the mass extinction.

Top 5 Mass Extinctions
End of Cretaceous, Cretaceous-Tertiary (K-Pg)
70% of all species
End of Triassic
65% of all marine species
Permo-Triassic
96% of marine, 70% of terrestrial species
End of Devonian
Loss of many trilobites, sponges, armored fishes
End of Ordovician
Reduction of plankton, trilobites, corals brachiopods

late cretaceous fatality list

Terrestrial
Non-avian dinosaurs
Pterosaurs (only one family present at end, it went extinct)
Many Plants - especially in North America (loss of 57% of species)
In southern latitudes, no major extinctions - but major disruption and long recovery
Compiling extinction data is difficult - tight time resolution required (usually only possible in marine sediments).

Marine
Vertebrates
Most marine reptiles
Mosasaurus
Plesiosaurs
Ichthyosaurs (died out long before end)
Invertebrates
Ammonites - total extinction (their larvae were planktonic)
Rudistid bivalves - total extinction
Coral - loss of 50% of genera
Biggest impact on planktonic organisms
This is the base of the food chain. Loss of plankton leads to loss of filter-feeders, fish, ammonite, and their predators - mosasaurs

Terrestrial
Lepidosaurs (lizards, snakes, etc.), unscathed
Amphibians - essentially unaffected
Turtles - 20% loss
Crocodilians - loss of 50%
Birds
Primitive clades went extinct
Others survived
Mammals
All major groups survived, but in North America, loss of 50% of species from some clades (and nearly all North American marsupials)

Explain the history of the development of the bolide impact hypothesis as an example of how science works: (1) How did the theory develop, (2) how was it accepted, and (3) how long did it take to be rejected or accepted?

K-Pg Impact - An Example of How Science Works
How did the theory develop?
In 1980 a novel hypothesis (asteroid impact) was proposed
Few liked the idea
How was it accepted?
Evidence accumulated supporting it
In 1990 a matching impact structure was found
Still, man said it happened after the extinction, or was simply the final blow
In April 2019, new evidence of the widespread destruction was presented
How long did it take to be rejected or accepted?
1980 to today, where we review the development of this hypothesis and the path to its widespread acceptance.

Know the major evidence that supports a large impact.

The Magic Clay Layer
The K-Pg boundary is marked by a layer of clay when preserved in lacustrine and marine environments
Clay is about 1” or so thick
Begged Questions…
What is the origin of the clay layers?
How long did it take to be deposited?
Terrestrial Examples
Found some time after marine examples were known
1980 Father and son team from Berkeley
Walter Alvarez, his father Luis Alvarez and others
Sought to determine amount of time represented by boundary clay
Proposed use of “meteoritic dust” clock
20,000 tonnes (metric ton) of meteoritic dust settles on Earth each year
Used 24 metals rare on Earth, known to originate from meteoritic material

Clay Lay @ Gubbio, Italy
Background iridium = .01 parts/billion
Their samples had 30 to 130 times the expected amount of iridium.
With normal meteoric dust would take - 1+ Ma to deposit the clay
Improbable, sought to explain concentration
Test Hypotheses
Rare metal analysis eliminated supernova hypothesis - no plutonium 244 found (half life 80 Ma, forms in neutron rich environments)
Found much Iridium, which is very rare on Earth
Not from volcanic source
Concentration too great
Blast event called for 1000 billion tonnes of clay
Propose New Hypothesis
Conclusion 1980
Comet or asteroid struck Earth
These contain great concentration of iridium
10 (16) km in diameter to account for amount of iridium
They hypothesized the clay was
9% meteoritic matter
91% pulverized target rock

Results of Impact
Dust cloud sulfuric acid (from gypsum in impact area) would block out 10 to 20% of Sun’s rays for up to 10 years
Intense heat from impact could incinerate much of terrestrial life
Reduced plant and phytoplankton growth disrupted food chain
Test New Hypothesis
Independent iridium measurements at 40+ clay sites worldwide
Confirmed iridium anomaly
In North America the clay had 2 novel components
Tektites
- Rock melted at impact site shot into air, cooled, fell to Earth as glass
Shocked Quartz
Micro “fractured” sand grains

Collected Corroborating Data using other factors
Shocked Quartz
Dislocations in crystal structure
Vitrification bands
Found only at
Impact sites
Underground nuclear blast chambers
(it had long been argued by opponents of the theory that shocked quartz could have been related to volcanism - not so)
Found in western NA and eastern Pacific, only

Micro diamonds
Hey - Let's disprove the theory…
A palynologist (paleontologist that studies pollen and spores) and his associates set out to collect data to argue against the impact theory. Instead they found corroborating data in the form of…
Micro diamonds
Submicroscopic
Electron Microscope
X-ray equipment to ID

Fern Spike
Palynomorphs below and well above layer represent the expected variety of plants and in normal quantities
Just above layer palynomorph assemblage
Is dominated by ferns
Documents catastrophic environmental event

Know the evidence which led to the discovery of the impact site and where it is located.

Search for the Crater
What would you use to help find the location of the impact crater?
Look at known impact structures of correct size and age
Look for variance in conc. Of iridium
Look for increase in clay thickness
Look for increase in size of tektites
Look for impact related strata
Breakthrough
Clay contained
Quartz from continent
Tektites from ocean
Therefore impact was on continental margin

Chicxulub: Crater of Doom
Late 1980’s - still no candidate
Thought process
If impact was part oceanic
Look for tsunami-related strata
Found around Caribbean Ocean
Focused on 180 km structure in Yucatan, Mexico
White line marks Yucatan coast
White line marks Yucatan coast lineMagnetic map of impact structure.
180 km (112 mi) wide crater (now thought to be about 300 km (190 mi wide) - the original size was only the center of the structure

2019 North Dakota Surge Deposit at K-Pg Boundary
Numerous clay layer localities in North America
Tsunami type deposits around Gulf of Mexico long known, along with thick tektite deposits in and around the crate
This find reports a surge deposit in North Dakota related to seismic activity derived from the Chicxulub crater in Mexico - including tektites

Clay Layer
New site preserves clay layer above a 1.3 m thick surge deposit
The clay layer is known worldwide and is thought to have been deposited over a year or so, but deposits formed immediately after the impact were not known from such a long distance from impact

Know what changes may have caused or contributed to the end of Cretaceous extinction in terms of ecology.

Paleontological Evidences
Angiosperm pollen rare after impact
Fern spores abundant (fern spike)
Shifts in vegetation
Conifer forests in W NA (Cretaceous) shifts to
Deciduous in Tertiary
Detritivores could find food to eat and survive, or those that could burrow and wait until food was again available were most likely to survive. Dinosaurs (large and likely with high metabolic rates) simply could not find enough food and perished.

Explain what evidence supports the following claim and why it has been rejected: dinosaurs did not go extinct at the end of the Cretaceous, but lived on into the Paleocene.

Non-avian dinosaurs went extinct at end of Cretacous

Supports the Claim
But dinosaur bones are sometimes found in lower Cenozoic rock units (Paleocene). How can this be?

Why it has been rejected
Every once in a while, some scientists try to prove that some dinosaurs survived the extinction because dinosaur bones are found in Paleogene sediments
Bones from Upper Cretaceous rocks were eroded, moved, and redeposited in younger rocks. If articulated bones were found - it would lend credence the claim of Paleocene dinosaurs. All known bones, however, are isolated and usually often water-worn.

Know whether the K-T extinction was gradual or sudden and explain how different paleontologists view the evidence.

Debate continues whether it was the impact alone or multiple factors leading to extinction
Impact Scenario
Impact = 100 million megaton bomb
10,000 x larger than all nuclear weapons combined
1 billion times more energy than released by Hiroshima and Nagasaki atomic bombs
Mass = one thousand billion metric tons
Speed = 20 km/s
Blast ring at speed of sound 500 km away
Vacuum sucked air back
Blew down forests 1000 km distant
Tsunami 100 m tall
99% of energy converted into melting and vaporizing target, moving ejecta away
Ejecta = source of clay and its contents
200,000 cubic km
Pulled up by vacuum cone
Fell back over period of 1 year
Proposed worldwide fires - up to 400 C temp after fall (worst case)
Chemical poisoning of air
Nickel, a toxic metal world wide
Nitric and Sulfuric acid rain
“Nuclear” Winter effect

Biases
Because of location and angle of impact North America was hardest hit
Most terrestrial K-Pg studies are conducted in North America

Acceptance of Alvarez (impact) Hypothesis
Well accepted after about 10 years of data compilation (1990), including discovery of Yucatan site
It is a classic study of how theories are proposed, shift directions, and after massive quantities of corroborating data are amassed, finally generally accepted.

K-Pg extinction

Many paleontologists, especially those that study vertebrates, think the impact was only the final blow causing mass extinctions, not the prime cause.
Extinction was likely a function of dramatic environmental shifts, caused by volcanism, sea level drop, and finally, the impact (which marks the end of the Cretaceous

Know why bones and teeth of large, non-avian dinosaurs found above the K-T boundary are NOT evidence that large, non-avian dinosaurs survived the End-of-Cretaceous extinction event.

Bones from Upper Cretaceous rocks were eroded, moved, and redeposited in younger rocks. If articulated bones were found - it would lend credence the claim of Paleocene dinosaurs. All known bones, however, are isolated and usually often water-worn.
Teeth last a bonkers long time, which is why you might find whole ones - they can withstand a lot

Explain why nearly all paleontologists insist that non-avian dinosaurs went extinct at the end of the Cretaceous despite the occasional reporting of non-bird dinosaurs younger than the end of the Cretaceous.

Because the bones of these dinos gets picked up by a river and is deposited in younger sediment, so while some may say that means they survived, the reality is that the bones just got moved

Define Taphonomy.

Taphe = burial
Nomy = laws relating to
Taphonomy = study of what happened to an organism from the time of death to time of discovery
Transition from Living (biosphere) to Fossil (lithosphere)

Understand what taphonomy tells paleontologists and why it was originally developed.

Originated by Ivan Efremov 1940

Reveals biases in the fossil record
Another example - at Dalton Wells small bones are rare. Does that mean they didn’t live in the area?
Also in most dinosaur quarries, no plants are found. Does that mean there were no plants in the area?

The most commonly asked question in dinosaur quarries is…
How did all of these bones get here?
The next questions are…
Why are the skeletons perfect?
Or why are all the bones broken?
Taphonomy answers these questions!

Taphonomy Involves
Detailed study of sediments around the bone
Detailed studies of individual bones
Relationships between the bones
Analysis of bone size and shape

Understand what a bone bed is.

Fluvial preservation
Example: Dinosaur National Monument
Articulated and disarticulated bones (thousands of bones)

Understand why a detailed understanding of a quarry’s geology is so important to taphonomy.

If you are not aware of preservational biases - your interpretations of the biota will be wrong
The fossil record is highly biased toward organisms with hard parts
Boney/shelled organisms
Woody tissues & spores and pollen (plants)

Be able to explain why quarry maps, showing the location/orientation of bones, are important.

Types of dinosaur sites differing taphonomic models

Dinosaur Death Pose

Necropsy (death)

Biostratinomy
What happens between death but before burial
Decompositions of carcass
Fress, putrefaction, scavenging/consumption by microorganisms
After loss of most fluids = “mummification”
Loss of odor, cheese-appearance (natural soap)
This is how skin is preserved on dinosaurs

Diagenesis
Mineralization, or general preservation
Minerals, mainly calcite, form shortly after death
Mediated by bacterial action

Describe a typical dinosaur death pose.

Head over butt -tail curved as well

Explain the previous explanations for the death pose.

Drying out, Dying in water - the tendons relax all the way which expands them & stretches the head over the butt

Know the new factors used to explain the death pose and how it changes interpretations of the environment of death.

Neck ligaments and getting wet

Know which of the two clades of Dinosauria theropods belong to and describe this clade’s characteristics.

Saurischians
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

2 Clades;
Carnosaurs (meat lizards), large with short necks and small fore limbs
Coelurosaurs (hollow tail lizards); smaller with longer necks and longer forelimbs

Know how Herrerasaurus is 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

Know the features that are diagnostic of the theropods and what types of behavior can be inferred from such features.

Blade like serrated teeth
- promaxillary fenestra
- intramandibular joint (Extra joint in lower jaw, allows motion in lower jaw)
- enlarged hands with increased grasping ability
- Predatory
- All bipedal
- Tyrannosaurus, Velociraptor, Allosaurus
- Many were feathered
- Bird-like feet
- Enlarged hand with inky 4 or 3 fingers, with sharp claws, claw hands
- Grasping hands with large claws
- Lightly built theropod skulls

Know which clade of theropods is most closely related to birds and what features birds and this clade share

Clade: Coelurosauria
Shared features: enlarged brains, tridactyl hand with long second and third digit, feathers, hinge-like ankles

Know the major function of the furcula.

Fused collar bones
To strengthen skeleton, hold wings

Know which theropods are known to be feathered and had wings and what the function of the wings were in non-flying taxa.

Archaeopteryx, Yutyrannus (no wings but tons of feathers)
Insulation and or display rather than flight

Know the distinguishing features of ceratosaurs, carnosaurs, and coelurosaurs and be able to recognize members of each clade.

Ceratosaurs
Distinguishing features
Six or more sacral vertebrae
Very deep coracoids
Small forelimbs
Very small maybe nonfunctional
Only have four fingers
Members
Limusaurus
Aucasaurus
Abelisauroids

Carnosaurs
Features
Extra opening in maxillary
Very large nasal bones
Members
Allosaurus
Giganotosaurus

Coelurosaurs
Features
Most bird like dinosaur
Enlarged brains
Tridactyl hand with long second and third digit
Boat shaped chevron bones
Feathers
Members
Tyrannosaurids
Maniraportiformes
Compsognathus

Know the unusual features of enigmatic coelurosaurs, such as oviraptorids & 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, describe the main characters of the group.

Small teeth with large serrations (Leaf shaped teeth)
Short necks- not as long as sauropods (Feeding over wide arc)
Jaw articulation offset– all teeth occluded simultaneously
Poorly pneumatized vertebrae
Obligate quadrupeds
Can be bipedal (more primitive feature)
No sharp claws

Know what anatomical evidence supports the notion that prosauropods were plant-eaters.

Long necks that feed over a wide arc side to side
Teeth look like modern Iguanas and are known as herbivores
Do not have sharp claws- not theropods (meat eaters)

Explain why most paleontologists exclude any known prosauropod from the ancestry of sauropods.

Because theropods are ancestors are sauropods, but they’re distinguished enough from sauropods that they have been given their own clade
Prosauropods have a small 5th digit

Know the two sauropodomorph groups and know the features that distinguish them from other dinosaurs.

Prosauropoda and Sauropoda

Explain why vertebrae in the shoulder region are the most widely used diagnostic elements in sauropod classification.

Fragile skulls- can’t rely on these to compare. Vertebrae

Compare and contrast the skulls of diplodocid, camarasaurus, brachiosaurid 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
Longer humerus than femur
Dip in pre-maxilla

Shunosaurus
Teeth facing forward
No dip in pre-maxilla like the brachiosaurus

Explain how the confusion about the name and the skull of Brontosaurus resolved?

It was actually an apatosaurus (a diplodocid), but they originally had the head of a camarasaurus on it. Eventually they found one with the right skull nearby and fixed it.

Know the possible mechanisms for the development of long sauropods and what saurischian characteristics allowed them to develop the longest necks of any vertebrates in the history of the earth.

Long neck:
- Allows feeding over wide arc (side to side)
- How could they be so long?
only because vertebrae are so light (pneumatic)
- Methods of developing long 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

Understand the significance of pneumatic vertebrae and their effect on the structure of the vertebrae in sauropods.

Added air so it was lighter
Keeps their necks strong but light
Allows them to feed with necks extended

Understand the relationship between skull size and neck length in sauropods

Smaller skulls= longer necks.

Know the evidence that suggests diplodocids could not raise their heads above the shoulders.

Necks were straight but heads were angled down, necks were not very flexible only side to side motions
Good for side to side, neck posture oriented down

Compare and contrast the feeding strategies of grazers vs high browsers

High browser - longer humerus than femur, reaching into trees to feed from branches
Grazers - (no grasses, most likely ferns and other), low energy to graze on the ground, longer femur than humerus

Know when ornithischia lived and describe their distinguishing characteristics.

Self sharpening teeth, feathers, scales, have cheeks, ridges in maxilla and dentary
Longest lived dino-middle jurassic to end of cretaceous

Know what dental batteries are, how they function, which groups possess them.

Teeth stacked on each other in sockets.

Explain how dental batteries allowed ornithischians to be successful.

Constantly had new teeth, losing them wasn’t a big deal, Got worn down by chewing.

Explain which ornithischians have asymmetrical tooth enamel, which clade is defined by this feature, and describe its function.

Neornithischia
Self-sharpening teeth
Thick enamel on the outside, thin on the inside

Know what features of the skeletons of different groups of ornithopods identify them as either bipeds or facultative bipeds.

Bipeds: Walks on 2 legs; much shorter forelegs. How the head is anchored.

Facultative bipeds: Walks on 4 but can on 2 for mating and eating; The head would be anchored more at the back of the head rather than the bottom so it is better for eating on all fours.
Prosauropods

Describe the hand of Iguanodon and its diagnostic features.

Thumb claw, spikey
Opposable pinky finger with 6 bones to grasp things with.
3 fingers to walk on like hooves

Compare and contrast the Hadrosaurine and Lambeosaurine clades of the Hadrosauridae

Both: extra motion to process food in jaw that grinds food
Hadrosaurine: heavily built, wide snouts, dental batteries, enlarged nares sometimes,
Lambeosaurines: crested skulls (impacted by age and sex), relatively lightly built, narrower snouts compared to hadresoaurine, dental batteries

Explain the specialized features of hadrosaurid skulls, particularly those related to feeding (beaks, diastema, cheeks, extra skull joints, tongue).

Diastema
Gap between beak/premaxilla teeth and back teeth
There so the tongue can bring food from the cheek to in the mouth

Cheeks
There to catch the food that falls out of the teeth during the grinding process

Extra skull joints
Allows teeth on maxilla to move back and forth
Better grinds the food
https://www.youtube.com/watch?v=DZkYcyYdZJU

Beaks
Broad with no teeth

Know the function of the hollow tubes and crests on the lambeosaurine skulls.

Display and sound

Know which clade most likely had cheeks and the evidence to support this.

Evidence: ridges on skull above teeth is where cheek muscles would’ve connected
Clade: Ornithischians

Explain what the beak shape reveals about feeding habits.

Wider beak = grazer
Narrow beak = browsers
They’d use beaks to clip the vegetation before chewing it in their weird way. Likely grazed on horse tail like plants like thick and fuzzy grasses and leaves. Likely low browsers based on copperlites. But not grass, grass didnt exist until L cretaceous and wasn’t common even then.