Geology Final

Furcula

(=little fork) is the 2 clavicle bones fused into the "wishbone"

Troodon

- first described by Joseph Leidy, 1856, on teeth from Montana. Latest Cretaceous. Small, 2 m long, slender and light-weight (~40 kg). Large eyes compared with other dromaeosaurs, the largest brain: body size of any dinosaur.

Saurischia hip structure

-Note the pubis pointing forward, with a large "boot" on the end. This is for extra muscle attachment Saurischia hip structure Lizard hipped

What separates dinosaurs from other reptiles? Think post-orbital fenestrae, ankle and hip structure

-Reptiles (Reptilia) are defined by the number and arrangement of skull bones, the number of fenestrae (holes) behind the eye socket (post-orbital fenestra), the pelvic (hip) and pectoral (shoulder) girdles, and the limb bones. -A hole in the skull is called a fenestra (= window). -Arrangement of skull bones in the Reptilia: (REPTILE) A. No fenestra = Anapsida: includes basal reptiles B. One fenestra is the Synapsida = mammal-likereptiles A. Two fenestrae is the Diapsida= includes all other living and extinct reptiles. Characteristics associated with the upright stance (DINO) 1. At least 3 -but most commonly 5 -fused vertebrae forming the sacrum 2. Expanded ilium of pelvic girdle to attach to the sacrum 3. Pelvic girdle with acetabulum -the socket into which the ball of the femur fits. Dinosaurs had a hole in the back of the acetabulum. 4. Femur with angled ball joint to fit into acetabulum 5. Ribs with two heads (attachment to vertebrae) 6. A complex, forward-facing shoulder girdle

Tyrannosaurids:

-S-shaped neck, to support the -largest skull per body mass of any dinosaur. -Up to 60 teeth at any one time -Long heavy tail to counterbalance the huge head. -Massive leg and feet bones -Very small, two-fingered hand

What are the two clades of dinosaurs and how are they distinguished - think hip structure

-The bones of the pelvis are called the ilium (il), ischium (is) and the pubis (pu). -Ornithischia all herbivores = bird hipped -Ornithischian hip structure - tip of pubic bone pointing posteriorly -Leaf-shaped teeth -Ossified (turned to bone) tendons along the backbone -Saurischia both herbivores and carnivores = lizard hipped -Note the pubis pointing forward, with a large "boot" on the end. This is for extra muscle attachment -Very long necks and tails, with many cervical (neck) and caudal (tail) vertebrae -erect pillar-like limbs--forelimb shorter than hind limb but not a lot shorter (except Brachiosaurus) -forelimb bones modified to sustain great weight -very small skulls (and small brains) -small simple teeth (without inset tooth row) -large nares located high up on the skulls, rather than being located at the end of the snout -The arrangement of the three pelvic bones defines the two clades

Drawbacks to endothermy

-if they had been warm-blooded, large dinosaurs would have cooked from the inside, like a baking potato! They would have been unable to dissipate the heat they generated internally. -Huge quantities of food are necessary to maintain endothermic metabolism

Theropoda (means 'beast' foot)

-includes all the carnivorous dinosaurs -They first arose in the mid-Triassic (Eodromaeus), expanded in the late Triassic (e.g. Coelophysis) and were very diverse throughout the Jurassic and Cretaceous. -Bird like foot 1. bipedal 2. hollow limb bones 3. sharp, serrated teeth 4. furcula (clavicle bones fused into wishbone) 5. primitively 4 digits on hand, with further modifications of the hands and feet 6. larger brain:body weight ratio

More derived theropods - the tetanurae (=fused or stiff tails)

1. Projections of bone on the tail vertebrae to keep the tail stiff. 2. Many bird-like features e.g. Reduction of teeth so all teeth are in front of orbit 3. 2nd antorbital fenestra 4. Hind limbs modified for fast running 5.rounded rib-cages shape suggest a sophisticated air-sac ventilated lung system, which exists today only in birds.

When did Dinosaurs first appear ?

Dinosaurs did not appear until ~20 million years after the P-Tr boundary, around 230 ma. The Permian-Triassic Period (P-Tr) boundary marks the largest mass extinction on Earth. It is estimated that over 90% of marine species and perhaps 75% of land species went extinct!

Saurischia

Herbivores and carnivores Very long necks and tails, with many cervical (neck) and caudal (tail) vertebrae -erect pillar-like limbs--forelimb shorter than hind limb but not a lot shorter (except Brachiosaurus) -forelimb bones modified to sustain great weight -very small skulls (and small brains) -small simple teeth (without inset tooth row) -large nares located high up on the skulls, rather than being located at the end of the snout

Gallimimus

Late Cretaceous Mongolia 6 meters tall

Mesothermy

Mesotherms raise their body temperature metabolically, but do not "defend" a certain endpoint temperature the way endotherms do.

Vocab

Nares = nasal opening Orbit = eye opening Antorbital = in front of the orbit (eye) Post orbital = behind the orbit (eye) Anterior = toward the front Posterior = toward the back Dorsal = top

Parasaurolophus

Spelling Counts

Triceratops

Spelling Counts

Tyrannosaurus

Spelling Counts

Spinosaurus

Spelling counts

Primitive theropods

Spinosaurus • Carcharodontosaurus • Megalosaurus • Allosaurus Characteristics: • Very large femur • Long, narrow skull • Large orbits • Good-sized forelimbs

In what kind of sedimentary environments are dinosaurs usually fossilized ?

Swamps, lakes, and coastal areas

Order and relative age of sedimentary rocks

The particles laid down at one time are covered by particles laid down subsequently

it was suggested that sauropods at least were behavioral homeotherms

They used external heat sources to raise body temperature above that of ambient air, but maintain a higher temperature through behavioral adaptations, e.g. crocodiles basking.

What are the periods of the Mesozoic

Triassic, Jurassic, and Cretaceous 230-66 Ma

Derived theropods - Coelurasaurs

Tyrannosaurids Characteristics: • Most bird-like of all dinosaurs • Mostly Cretaceous • Range of sizes from chicken-size to tyrannosaurids • Three-fingered hand (two fingered in the case of Tyrannosaurs) • Larger brains

Homeothermy

an animal maintains a near constant body temperature above that of ambient air. This can be done two ways: - Endothermy - warm-blooded. The animal maintains a higher temperature through its faster metabolism. - Behavioral, e.g. an animal absorbs heat from the sun, but is large enough to hold a large amount of the heat, keeping its temperature above air temperature.

ornithischian dinosaurs

basal ornithischians, thyreophorans, ornithopoda and the marginocephalians All herbivores Leaf-shaped teeth Ossified (turned to bone) tendons along the backbone

Ectothermy

cold blooded. The animal is dependent on ambient temperature. It makes little effort to maintain its temperature and can only be active when temperatures are warm.

Apatosaurus

might have reached its full size in as few as 10 to 12 years

Arguments that dinosaurs were endothermic

size, bone structure, insulation, chest capacity, eating behavior, geographic distribution

Brachiosaurus

the only sauropod that had the skeletal structure to hold its head up high. Also, it was the only dinosaur with longer front limbs than hind limbs

-Ornithischian hip structure

tip of pubic bone pointing posteriorly (Bird hipped)

Oviraptors

• Late Cretaceous (~ 70-75 Ma) • Mongolia. • First skull collected by Roy Chapman Andrews (1923) many bones together with of lots of eggs - assumed to be an egg-eater • Strong beak, no teeth • Diet uncertain

Deinonychosaurs

• small, very speedy derived theropods • mid-Jurassic to end-Cretaceous. • North America, Europe, China, Mongolia, Japan, Madagascar, Argentina and now Antarctica