Lecture 2: Dinosaur Classification Flashcards
(27 cards)
Who is Richard Owen?
British anatomist that coined the term “dinosauria”
When did Richard Owen coin the term “Dinosauria”? and which dinosaur was first discovered?
1842
Megalosaurus
Dinosauria in Greek meaning?
Deinos ‘terrible’
Sauros ‘Lizard’
Terrible Lizard
About the Megalosaurus and which bones were found?
Lived in the middle Jurassic
-skull fragments found in coal mines
-Bones included: Dentary, Maxilla
Name the parts of a Dino Skull + description (Megalosaurus)
Cranium: upper jaw
Maxilla: holds upper jaw teeth
Mandible: lower jaw
Dentary: holds lower jaw teeth
What’s a cladogram?
Shows evolutionary similarities between organisms, based on the traits which first appear from the ancestor to each descendent.
What’s a Clade? and how is it Monophyletic?
Group of organisms that share a common ancestor, which includes all descendants of that common ancestor
What are the 2 groups that divided dinosaurs?
Saurischia + Ornithishchia
What is a node?
Where the first trait between common decedents of a clade are found
Which bones make up the hip of a dinosaur?
Ilium, Ischium, pubis
What are the 2 types of hips found generally in dinosaurs? and how are they described?
Saurischia = Lizard hipped
-Ischium + pubis are perpendicular to ilium (pendulum shaped)
Ornithischia = Bird hipped
-Prongs (Ischium + pubis) are parallel to ilium
What is convergent evolution? and explain bird hips?
Similar traits evolve from different species over time “independent evolution”
-Birds evolved to be ‘lizard hipped’ compared to ‘bird hipped’ due to convergent evolution
Saurischia clade members?
-Sauropodomorpha (Lizard foot forms) “Brachiosaurus”
-Theropoda (Beast foot) “T-REX”
Sauropod evolution
Basal Sauropodomorphs “prosauropods” which evolved into sauropods “long necked”
Theropoda evolution
Includes all bipedal meat eating dinosaurs
Coelurosaurs?
Derived from Theropods, including meat eaters, omnivores, plant eaters and others
What are ornithischias traits that are not seen in Saurischia? and their primitive members?
‘bird hipped’
-Toothless predentary/premaxila + ossified tendons along back (for structural support)
-Thyreophora
-Marginocephalia
-Ornithopoda
-Pachycephalosauria
Ornithopoda traits?
From the clade of Ornithischia
‘Bird foot’ Dinosaurs that walk on 3 digits
no armour (meaty dinos)
Bipedal walking
Thyreophora traits? and examples?
From the clade of Ornithischia
Shield-bearing dinosaurs
-Rows of armour plates and spikes above and along vertebral column
Includes Stegosauria and Ankylosauria
Marginocephalia traits? + examples?
Margin-headed dinosaurs
-Thickened ridge of bone at the back of skull
includes Ceratopsia and Pachycephalosauria
Non-Avian Dinosaur Extinction
Avian Theropods (birds) are the only surviving members from the dinosauria clade
Amongst therapoda, who sees the most development of wide diversity of lifestyle, including carnivores, omnivores and herbivores?
coelurosauria
Ossified Tendons on a tail fossil skeleton comes from which types of Dinos?
Ornithischian and Coelurosaurs
Which clade does Iguanodon belong to?
Ornithopoda
