EPS SCI 17 Midterm

Archaeopteryx

Saurischian Theropod

Late Jurassic

An intermediate fossil that shows both reptile and bird characteristics.

Herrerasaurus

Saurischian

Late Triassic

One of the earliest known dinosaurs

Majungasaurus

Abelisaurid Theropod

Tiny arms

Late Cretaceous

more teeth than any other abelisaurus

southern hemisphere

Carnotaurus

Allosaurid Theropod

Smallest Allosaurid

heavy headed + horns

southern hemisphere

Dilophosaurus

Theropod

Early Jurassic - Cretaceous

Horned hunter dinosaur
Related to Ceratosaurus

Tyrannosaurus Rex

Last large theropod to rule

Late Cretaceous

Robust wide skull, heaviest land animal, crushing bite. King of Cretaceous

Deinonychus

Dromaeosaurid Theropod

Early Cretaceous

"Terrible claw"; a genus of carnivorous dromaeosaurid coelurosaurian dinosaurs, with one described species

Led to start of the dinosaur renaissance

Velociraptor

Dromaeosaurid Theropod

Late Cretaceous

Had a large manus "hand" with three strongly curved claws, which were similar in construction and flexibility to the bones of modern birds

May have had feathers

Spinosaurus

Spinosauridae Theropod

Cretaceous

Likely the largest and tallest Dino. Though very slim and light.

Sail backs and duck bill snout

Semi-aquatic (dense bones)

Allosaurus

Theropod

Late Jurassic

One of the earliest dinosaurs found. Gave name to HUGE allosaurids

Reduce bone strength but very light

Oviraptor

Theropod

Late Cretaceous

Carried eggs, may have eaten eggs

Possibly omnivore

Ornithomimus

Late Theropod

Very fast

Cretaceous of Laurasia, possible also Gondwana

Some have bizzare feeding adaptations (duck-like beaks, diverse in size and diet)

Therizinosaurus

Theropod

Late Cretaceous

Known for their huge claws and resembled sloths

Possibly herbivores

Microraptor

Dromaeosaur Theropod

Early Cretaceous

Among the smallest-known non-avian dinosaurs (1kg)

Camarasaurus

Sauropod

Late Jurassic

Giant herbivores
Hollow chamber in vertebrae

Diplodocus

Sauropod

Late Jurassic North America

Possibly longest dinosaur
Two rows of bones just for tail

Plateosaurus

Sauropod-ish

Late Triassic North America

Facultative Bipeds- capable of walking or running on two legs often for a limited period in spite of normally walking or running on four limbs or more
-Shows transition

Social

Iguanodon

Ornithopod

Mid-Jurassic to Late Cretaceous

Second dino to ever be identified and named

First described herbivorous dino

Maiasaurus Peeblesorum

Hadrosaurid Ornithopod

Jurassic/Cretaceous

Evidence of parental care

Transition between fast bipedal and duckbilled quadriped herbivores

Phytosaurs

Croc Relatives

Triassic

Sprawled limbs, robust tails, armor plates embedded in the skin, elongate skulls lined with sharp cone-shaped teeth, nostrils faced upwards.

Pseudosuchians

Croc relatives

Triassic

Top Predator in Triassic

Homo sapiens

Modern humans

Dimetrodon

carnivorous mammal like reptile, of the genus ​Dimetrodon

Permian Era North America

Long and usually bearing spinal sails. Look like dinos but only one postorbital fenestra

How did the concept of dinosaurs come to its current state over the past 200 years?

1800 - age of reptiles, reconstruction based on living animals, baby 6k earth, research by rich people, could animals go EXTINCT??
1850 - public dino hype, bone wars
1900 - dino renaissance, big ideas about dinos (parents, endothermy, new posture), dinos \=/\= lizards
1950+ dino ancestry of birds
1980 - Discovery of the iridium anomaly at the K-T boundary. CATASTROPHY?
2000s - soft tissue FLUFFY dinos???

What are the origins of dinosaurs in time and on Earth?

When: Mesozoic Era - Triassic period
Where: Pangea, edges-ish

What is a dinosaur?

Terrestrial diapsids with ornithodire (joints cleanly separate) ankles that lived in the Mesozoic
2 skull-holes, diapsid skulls, and upright posture.

Which vertebrates are the closest relatives of the dinosaurs? (One is extinct)

Archosaurs (including crocodilians), can be identified by the ankles, which have a crurotarsal ankle joint (dinosaurs and pterosaurs have a mesotarsal ankle joint)

What major characters define Ornithodires?

Ornithodires: Archosaurs that more closely resemble birds than crocodilians
-Mesotarsal ankles
-Covered in feathers
-Lineage where dinosaurs and pterosaurs split

What major characters define Ornithischians?

Pelvis bone: Pubis angled towards the TAIL, parallel with ishium

What characters define Saurischians?

pelvis bone: Pubis angled towards HEAD, right angle with ishium

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Which diet characterizes each branch of the Ceolurosaur theopod family tree? Can you point out a skull or forelimb trait to support that answer?

Therazinosaurs
-Possibly herbivore
-Sloth appearance and long claws don't suggest hunting or tearing flesh

Oviraptors
-Possibly ate eggs, fish, and shellfish
-beak, no teeth, great crushing power

Ornithomimids
-Not carnivore, Omnivore possibly
-No teeth and very light and fast build

What techniques are used to obtain a relative date for a fossil? An absolute date?

Absolute date: Radiometric dating (for rocks not fossils)

Relative date: Superposition (older vs younger rocks), principle of original horizontality

When was the Mesozoic and what time periods are in it, in order?

250m to 66m years ago
Triassic, Jurassic, Cretaceous

In which time period did the ancestors of most animals (including that of vertebrates) show up

cambrian

How did vertebrates combat dessication?

adults- thick skin
young- amniotic egg

What are dry-land living animals called?

terrestrial

In 1) the Permian and 2) the early Mesozoic, what lineages of amniotes were dominant on theland? What were dinosaurs like at these time (if they were around)?

1) Permian: synapsids "mammal like reptiles," don't have soft tissue that define mammals now (i.e. fur), Archosaurs (diapsid) are relatively small and uncommon, except in freshwater where crocs rule
2) early Mesozoic: (post great dying) rise of archosaurs, restart as small dinosaurs and predator of insects

What happened in the Great Dying?

A lot of the diversity was wiped out between the Permian and the Triassic, volcanism is to blame, acid rain poured out

Mesozoic began with 70% of all animal life newly dead

Allowed dinosaurs to quickly evolve and disperse into numerous empty niches and ecosystems

What were the earliest dinosaurs like? Describe as much of their physical traits and behavior as possible.

small, bipedal, carnivorous, agile
@herrerasaurus, one of the first dinosaurs

What kind of traits would you use a phylogenetic bracket to evaluate? Can you explain how a phylogenetic bracket works, using words or a diagram?

Traits: ankle joint, two post-oribtal fenestra, amniotic egg, four legs, land-dwelling, tetanurae

traits divide the different lineages at the circular nodes

Which big, carnivorous theropods were present on Laurasia?

Allosaurus: Late Jurassic period, around 155 to 145 million years ago.
Spinosaurus: Early Cretaceous period, around 112 to 97 million years ago.
Tarbosaurus: Late Cretaceous period, around 70 to 65 million years ago.
Tyrannosaurus rex: Late Cretaceous period, around 68 to 66 million years ago.

Where and when did sauropods live? Which predators did they worry about?

Cretaceous North America

The early dinosaurs lived on which continent?

Pangea

You're wandering around Africa in the Cretaceous and you see a brutal scene of a theropod killing a baby titanosaur. Which of the following taxa does the theropod most likely belong to?

Abelisaurs

which mass extinctions benefited dinos in the long term?

end-Permian extinction / The Great Dying, terrestrial vertebrate species die out --\> rise of archosaurs

which mass extinction wiped dinos out

Cretaceous-Paleogene (K-Pg) extinction

How did plate tectonics affect climate in the Triassic?

supercontinent made inland h*lla hot, no ocean to regulate surface temperature

Which large group of dinos stays closest in body plan to the first dinos

theropods
bipedal, elongated hindlimbs, carnivore --\> sharp, serrated teeth

How does an herbivore's skeleton and gut change to optimize plant digestion? Why does each change have to happen?

long FATT gut to increase digestion of plant material, holds fiber digesting bacteria
teeth: Dozens of overlapping, ridged teeth, stomach stones to grind food
leg: 4 legged to support weight

Why were there so many herbivores coexisting in Mesozoic? mention the way energy moves thru ecosystem

@energy pyramid, plants form base of food chain and was abundant, plentiful source of energy for herbivores

which group of dinosaurs represents a transitional form for the sauropods?

prosauropods: sometimes walked on two legs, forearms for support, long narrow skulls, serrated leaf-like teeth
@Plateosaurus long neck, small teeth, could walk on four

which group of dinos represents a transitional form for the ornithopods

Heterodontids: mix of teeth, bipedal and small, maybe digging

what key trait allowed sauropods to feed enough to maintain their enormous bodies

Sauropod necks allow them to reach higher and/or sweep across an area without moving much

When and where did Ornithopods like lambeosaurines and iguanodontids live? Name a trait related to social behavior and a trait related to feeding that differs between these two

When: Late Cretaceous period
Where: North Hemisphere
Trait: lambeosaurs crest is hollow crested, could be use for sound signalling
Eating: Iguanodontids had broad, leaf-shaped teeth that were well-suited for grinding tough plant material
Eating: lambeosaurines had tooth batteries, hundreds of tiny teeth

which hemispheres do the supercontinents Lauasia and gondwana correspond to

North and South

which organisms are the closest living relatives of the dinos that we use for phylogentic bracketing

Birds!

Which big, carnivorous theropods were present on Gondwana?

Spinosaurus, Carcharodontosaurus, Abelisaurus, Megaraptor

What is the benefit to becoming a bigger predatory dino

1) Predator avoidance
2) greater range of prey species
3) improved thermal efficiency
4) advantageous against other carnivores

How does getting bigger and hypercarnivorous put the species at risk of extinction? (mention energy movement thru ecosystem)

Large bodies require large prey to survive, but ecosystems cannot support too many large predators because energy is lost throughout ecosystem

What did the results of Finite Element Analysis say about T. rex's skull?
A.It had less mobility between skull bones than other theropods
B.All of these
C.It would have been able to crunch and pull teeth through prey's bones
D.It was able to withstand immense stress and strain from biting down

B) all of these

According to modeling and observations of living archosaurs, which feature was key to T. rex hunting using bursts of speed?

hyper efficient lungs

What does it mean when we say theropods were airheads

Their skulls were filled with air sacs.

the largest theropods like majungasaurus and T rex also had the greatest

skull pneumaticity

From early point along their history, tyrannosaurs had increased emphasis on what senses?

hearing, vision, scent

what are T. rex arms believed to be primarily used for?

holding strugglling prey