Lecture 8 - how many types of Dinosaurs are there? Flashcards
All birds are ______ but
all birds are dinosaurs but not all dinosaurs are birds
What are the 3 periods that the dinos were alive during?
Triassic, jurrasic, cretaceous
The oldest known confirmed dinosaur material is from _______ and was found in _____Ma. Their traits are very primitive
Argentina. 229-218
Morphospecies
Group of species that have some reliable characteristics distinguishing them from all other species
What is the problem with defining morphospecies?
We can’t always tell if the observed variation is due to individual variation, sexual dimorphism, ontogenetic change, or incomplete fossil record
Ontongeneic changes
changes over life span. Puberty vs child vs adult
What are the 3 major groups of Dinosaurs?
Theropods
Sauropodomorphs
Ornithischians
Theropods
meat eating - TRex
Sauropodomorphs
Long-necked dinosaur
Ornithischians
Everything else
Harry Seeley
Recognized that all dinos have 3 bons that make up the pelvic girdle
What are the 3 pelic bones?
ilium
ischium
pubis
How can the pubis be oriented? 2 ways
- Down and slightly forward as in the lizard-hipped (saurischians)
- Part of it points backwards as in the bird-hippped dinosaurs
How is the pubic bone pointed in saurischians?
Down and forward
How is the pubic bone pointed in ornithiscians?
a part is pointed backward and lies along the ischium
Based on the hips, _____ and ______ are considered saurischians. And all other dinos are _____
therapods. sauropodomorphs. ornithischians
Which lineage led to birds? Ornithiscia or the sarischia?
Saurischian
What are some features of ornithischia?
Predentary bone
Palpebral (narrow bone)
Is there more evidential support for ornithischia or saurischia?
Or
The _________ are a really well defined group of dinosaurs
ornithischia
When was the big reorganization?
2017
In 2017, Baron et al re-analyzed the morphologic characters and proposed a new cladorgram which group…
theropods and ornithischians into a new group called the ornithoscelida
Describe the classic interpretation changing into the Baron et al. 2017 cladogram
The therapods have been kicked out of the daurischia suggeting that —
hips are not a diagnostic character