Today – 4/10 Sauropodomorpha Sauropods in Argentina

Small genomes in theropods Small bone cells = small genomes in living vertebrates, so we can get dino genome size Also correlated with high metabolic rates, longevity, and high growth rates Originally 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

Clade Prosauropoda High-level grazers – facultatively bipedal, very slow animals Vestigial little toe Plateosaurus – 220 Ma, German bone bed, five fingers, 26 ft long, 1,500 lbs. Babies probably required parental care, born quadrupedal Gizzard stones First known dinosaur – 230 Ma in Madagascar, went extinct ~183 Ma Found 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 ideas Didn’t evolve from prosauropods – Triassic sauropods found in the last five years, well- developed little toe, baby prosauropods were quadrupedal Didn’t live mostly submerged – trackways, body shape like a rhino, not a hippo, often found in semi-arid environments Most were low-level grazers, didn’t browse the treetops. Neck motion 90° horizontally, only ° vertically. Brachiosaurs to 45°. Belies “evolutionary arms race” trees vs. dinos Didn’t lay eggs while walking Grew 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

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 isotopes Cold-climate dinosaurs Predator/prey ratios Heart with four chambers, single aorta Brooding Feathers Growth rates Body morphology indicating active lifestyle Close relatives of birds, many shared traits