Today – 4/10Today – 4/10

• Sauropodomorpha

• Sauropods in Argentina

Small genomes in theropods

Small bone cells = small genomes in living vertebrates, so we can get dino genome sizeAlso correlated with high metabolic rates, longevity, and high growth ratesOriginally thought to have evolved in birds to reduce energy of cell production, now an item on the list of “bird” characteristics that first evolved in dinos – feathers, nesting and parental care, pneumatization, small genome, warm-bloodedness

Last time

Warm-bloodedness

Little Das

Last XC opportunity!

Geodaze 4-pt XC opportunity Thursday 4/12, Ballroom A, Student Union, 1-2:30

Come to poster session, interview one of the authors, write one-pager

3-paragraph one-pager

What did the authors find? – their data, their interpretation

What questions were they trying to answer? Ask what the big picture is, and where their work fits into it

What do you think

Evolutionary convergence

Gross morphological similarity between distantly related organisms that evolved because they are filling similar ecological niches – they evolved similar body plans because they are doing similar jobs

Birds, pterosaurs, bats

Ichthyosaurs, dolphins

Clade Sauropodomorpha!

From the very beginning to the very end

Some shared derived characters – hind limb relatively short compared to torso length, spatulate teeth, big thumb claw, funky ankle bone

Two subclades – Prosauropoda, Sauropoda

Healthy animals, unlike theropods

Gizzard stones, strippers not chewers, esp. sauropods – likely not doing much more than raking the vegetation

Extremely low EQ’s!

Saturnalia – the oldest known sauropodomorph. Discovered in Brazil during the Roman winter solstice festival, Saturnalia, possibly part of the origin of Christmas

5 ft long, 225 Ma

Plateosaurus

http://www.dinosaurios.net

Clade ProsauropodaHigh-level grazers – facultatively bipedal, very slow animalsVestigial little toePlateosaurus – 220 Ma, German bone bed, five fingers, 26 ft long, 1,500 lbs.Babies probably required parental care, born quadrupedalGizzard stonesFirst known dinosaur – 230 Ma in Madagascar, went extinct ~183 MaFound in groups

Clade Sauropoda!

Antetonitrus

Oldest sauropods

Antetonitrus – 215 Ma, South Africa, 30 ft long, 6 ft at the hips

Sauropod footprints from N AZ 224 Ma!

Some old, wrong ideasDidn’t evolve from prosauropods – Triassic sauropods found in the last five years, well-developed little toe, baby prosauropods were quadrupedalDidn’t live mostly submerged – trackways, body shape like a rhino, not a hippo, often found in semi-arid environmentsMost were low-level grazers, didn’t browse the treetops. Neck motion 90° horizontally, only 10-20° vertically. Brachiosaurs to 45°. Belies “evolutionary arms race” trees vs. dinosDidn’t lay eggs while walkingGrew very fast, not like reptiles

Sauropods!Apatosaurus – 150 Ma, 80 feet long, 15 ft tall at the hips, 35 tons. Head less than 2 ft long – skulls of sauropods extremely rare. 90 % grown in 10 years!

Brachiosaurus – 150 Ma, 85 feet long, 23 ft tall at the hips, 70 tons. Arms longer than legs. “Veggiesaurus”

Alamosaurus – 72 Ma in Tucson!, 70 ft long, 33 tons, probably armored, member of the titanosaurs

http://critters.pixel-shack.com/

Longest neck (?) 45 ft - Mamenchisaurus

Evidence for social behavior in sauropodomorphs

Trackways – parallel, spaced. Upper Jurassic of Portugal – 3 adults, 7 juveniles

Colonial nesting with site fidelity

Possible fossilized family units – Argentina 5 individuals young and old, Wyoming two adults and one juvenile Camarasaurus

Alamosaurus bone bed, prosauropod bone beds

Evidence for warm-bloodedness in theropods (and others)

Oxygen isotopesCold-climate dinosaursPredator/prey ratiosHeart with four chambers, single aortaBroodingFeathersGrowth ratesBody morphology indicating active lifestyleClose relatives of birds, many shared traits