38 Questions
What is the characteristic feature of the Saurischia group?
Lizard-hipped
Which of the following is NOT a likely ancestor of dinosaurs?
Pterosaurs
What is the likely stance of the ancestors of dinosaurs?
Obligate bipedal
Which group of dinosaurs is characterized by a full domed head?
Pachycephalosauria
What is the purpose of the domes in Pachycephalosauria?
For combat and wounding
What is the estimated weight of Triceratops?
6-7 tons
Which group of dinosaurs is characterized by a flat-headed skull?
Pachycephalosauria
What is the characteristic feature of the Ankylosauria group?
Presence of armor plates
What is the likely reason for the frequent occurrence of lesions in Pachycephalosauria?
Fighting with other Pachycephalosauria
What characteristic is common to all species of Maniraptor?
Possession of feathers
Which family of Sauropodomorpha dominated by the late Cretaceous?
Titanosaurs
What type of feathers are characterized by having a central shaft?
Pennaceous
What is the name of the largest land animal to have ever existed?
Argentinosaurus
What is the purpose of the structures of fossilized melanosomes?
To indicate pigmentation on the animal when alive
What is the name of the group of basal Theropods that lived around 230+ mya?
Herrerasauria
What is the name of the first fossil of Archaeopteryx that was found in 1860?
Archaeopteryx lithographica
What is the name of the group of Sauropods that includes Brachiosaurus?
Brachiosauridae
What is the name of the ancient archosaur lineage that produces beta-keratin?
Crocodiles
When did the first species of Iguanodon exist?
Early Jurassic
Which clade of reptiles includes turtles?
Anapsida
What is the likely characteristic of the ancestors of all dinosaurs?
Obligate bipedalism
What is the characteristic feature of the Stegosauria group?
Armored body with plates
What is the purpose of the fibroblasts in the bone of Pachycephalosauria?
To rapidly heal wounds
Which of the following is an early saurischian dinosaur?
Eoraptor
What is the characteristic feature of the Ankylosauria group?
Pattern of armour used to identify species
Which group of dinosaurs is characterized by having a lizard-hipped pelvis?
Saurischia
What is the estimated time range of the Lesothosaurus dinosaur?
220-225 mya
Which group of dinosaurs is characterized by having a bird-hipped pelvis?
Ornithischia
What is the characteristic that distinguishes the skulls of Hadrosaurines from those of Lambeosaurines?
Crests
What is the estimated length range of ornithopods?
1-12m
What is the name of the largest land animal that ever existed?
Argentinosaurus
What is the name of the group of basal Theropods that lived around 230+ mya?
Herrerasauria
What is the characteristic that all Maniraptors share?
Feathers
What is the name of the first fossil of Archaeopteryx that was found in 1860?
Archaeopteryx lithographica
What is the name of the family of Sauropodomorpha that dominated by the late Cretaceous?
Titanosauridae
What is the purpose of the structures of fossilized melanosomes?
To indicate pigmentation
What is the characteristic of the feathers found in Maniraptors?
All of the above
What is the significance of Crocodiles in the context of feathers?
They produce beta-keratin
Study Notes
Synapsids and Mammal-like Reptiles
- Reptilia includes anapsid (turtles) and diapsids (Lepidosauromorpha and Archosauria)
- Synapsids are mammal-like reptiles and mammals
Dinosaurs' Likely Ancestors
- Early thoughts included Pterosaurs as a likely candidate, e.g., Rhamphorynchus
- Marasuchus and Silesaurus are not likely to be ancestors of dinosaurs
- Other alternatives: Eoraptor (an early saurischian, 243 mya), Lesothosaurus (a primitive ornithischian, 220-225 mya)
- Ancestors of dinosaurs were probably obligate bipeds
Saurischia and Ornithischia
- Saurischia (lizard-hipped) and Ornithischia (bird-hipped) are two distinct groups
Stegosauria
- 13 genera from early Jurassic to early Cretaceous
- Peak of diversity in late Jurassic with 7 known species
Ankylosauria
- Nodosauridae and Ankylosauridae families
- Medium to large in size, mostly less than 5m long, but up to 9m
- Patterns of armour used to identify species
Pachycephalosauria
- Full domed, about 10 recognised species
- Flat-headed, number of species unknown
- Frequency of lesions suggest wounding during confrontation
- Domes were used in combat
Ceratopsians
- Triceratops and Styracosaurus
- Triceratops: 6-7 tons, large and well-known monophyletic group
Ornithopods
- Existed from the Early Jurassic until the end of the Cretaceous
- Adult length ranged from 1-2m up to 12m
- Excellent range of fossils collected from across the globe: 80 species known
Iguanodon
- Discovered in 1822 by Gideon and Mary Ann Mantell, Tilgate Forest, West Sussex
Sauropodomorpha
- Brachiosauridae: Brachiosaurus - 22.5m and over 60 tons
- Diplodocidae: Late Triassic - early Cretaceous
- By the late Cretaceous, the Titanosaurs dominated
- Argentinosaurus: biggest land animal ever at 40m and 99-110 tons
Theropoda
- Varied group containing many species from late Triassic until late Cretaceous
- Herrasauria: basal Theropods from 230+ mya, poorly known
- Ceratosauria: fast runners, short limbs often with thickened bones on head
Archaeopteryx
- First fossil found in 1860 from the Solnhofen quarry
- Had many typical Theropod characteristics and pneumatic bones
Maniraptors
- Oldest around 160 mya
- By the end of the Cretaceous, species that looked like modern birds existed
- Possession of feathers is common to all species of Maniraptor
- Feathers: filaments - plumulaceous - pennaceous
- Structures of fossilised melanosomes serve to indicate pigmentation on the animal when alive
Explore the evolution of dinosaurs and their possible ancestors. Learn about the relationships between reptiles, synapsids, and mammals. Discover the likely candidates that gave rise to these prehistoric creatures.
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