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Puertasaurus reuili
70 Ma – giant sauropods almost to the end!
125 ft long, 100 tons! Chest alone was 16 feet in diameter
Argentinian forest, occasionally flooded by Atlantic and Pacific – no Andes yet
Discovered by Pablo Puerta and Santiago Reuil
titanosaur
Clade Ceratosauria – “horned lizard”
Fused feet, ankles, pelvic region for hind limb strength, speed, narrow gait
Four fingers
Sexual dimorphism – “robust” form with thicker limbs, longer neck and skull; “gracile” form more svelte
Some had dramatic head gear for display, perhaps intraspecific combat
Carnotaurus – “meat-eating bull”
25 feet long, 7 feet tall at hips, 1 ton
Fast runner, biter, skull built to expand to swallow prey whole like a snake
Lived in the Late Cretaceous, 70 Ma (?), in Argentina
Only 1 found, but a beauty, including skin impressions
Partially binocular vision, like some other theropods
Coelophysis9 feet long, 3 feet tall at hips, 90 lbsMore than 100 specimens excavated at Ghost Ranch Quarry mass grave – evidence of social behaviorAll ages, great growth series shows age variationOnce thought to be cannibals – ate fish, small reptiles. Footprints show that they were very fastFound in Late Triassic (220 Ma) rocks in NM and AZ (Petrified Forest) representing large and small river systems, vast deserts, saline lakes, broad mudflats, and ocean shorelinesRobust and gracile forms occur in 50/50 ratio strongly indicating sexual dimorphism
More Coelophysis
Study of the eye ring comparing it to living lizards and birds shows that Coelophysis had a round (not slit) pupil, very good day vision on par with a hawk, poor night vision. Study of the skull and eye socket indicated good frontal binocular visionTrace fossil of a Coelophysis-like dinosaur shows protofeathers! Implies warm-bloodedness, perhaps all theropods had feathers
Effigia okeeffeae
Looks very dino-like, but actually a relative of Postosuchus (closer to crocodiles than dinosaurs)
From the Ghost Ranch Coelophysis Quarry
Ankle is the major give-away
Causing re-evaluation of other fragmentary Triassic remains
Dilophosaurus – “double-crested lizard”
20 feet long, 5 feet at the hips, 1000 lb
Three specimens from Early Jurassic (190 Ma?) rocks in N AZ, found near each other, one from China, now more
No evidence for spitting, frills
Many tracks likely made by Dilophosaurus found – more evidence of social behavior
Bone structure (LAGs) indicate high growth rates
Ceratosaurus
20 feet long, 1500 lb, new bigger ones
Late Jurassic, 150 Ma, Morrison Formation of Utah and Colorado
Nose horn
Dermal armor including back fin
Pretty good growth series showing significant changes from youth to adult. Young nose horn small, two halves unfused. Marker of sexual maturity