Lec 11 Dinosaurs & Birds Flashcards
(34 cards)
What are the synapomorphies of Avemetatarsalia?
(hints: 4 post-cranial, compared to crocodile)
shortened forelimbs, tibia longer than femur, mesotarsal ankle joint, no dorsal body osteoderms
What are the main clades in Avemetatarsalia?
Pterosauromorpha, Dinosauria
What are the 5 main features of Pterosaurs?
(3 post, 2 whole body)
Pteroid bone
elongated 4th finger supports wing membrane
Hollow bone with thin cortex
Pycnofibre integumentary covering
Synsacrum
What are the 3 synapomorphies of Dinosauria?
(all post-cranial)
- Deltopectoral crest on humerus
- Perforated acetabulum
- femoral head inturned and distinctly offset from the shaft
What are the two main clades of Dinosauria?
Saurischia, Ornithisichia
What are the 3 synapomorphies of Ornithischia?
(2 cranial, 1 post-cranial)
- Predentary
- ossified tendons along vertebral column
- tooth crown expanded above root
What are the characteristic of Ornithischia: Thyreophora?
(1 whole body)
extensive development of osteoderms
What are the 2 characteristics of Thyreophora: Stegosaurs?
(all post-cranial)
bony plates that ran vertically down the middle of the back; spikes on tail
What are the characteristics of Thyreophora: Ankylosauria?
Heavily armoured since osteoderms embedded in the skin
Bony tail clubs and bony eyelids
What are the 3 characteristics of Ornithischia: Ornithopoda?
- fossa-like depression on premaxilla-maxilla boundary
- paired frontals narrow and elongated
- fenestra located dorsally on surangular-dentary joint
What are 2 examples of Orithopoda?
Iguanodontia, Hadrosauridae
What are the 4 key features of Ornithischia: Orithopoda: Hadrosauridae?
(all cranial)
- dental battery w/ >=3 replacement teeth
- cranial crest formed of nasal bone
- circumnarial fossa
- lancoelate tooth crowns
What are the 5 key features of Ornithischia: Ceratopsidae?
(4 cranial, 1 post-cranial)
- rostral bone
- Horns on face
- Frills formed by parietal and squamosal
- Shearing dentition
- Syncervical bar (fused anterior neck vertebrae)
What are the uses of horns and frills in Ceratopsidae?
Socio-sexual display
What are the key features of Ornithischia: Pachycephalosauria?
(2 cranial, 1 post-cranial)
- Thickened frontoparietal dome of skull
- ornamented parietosquamosal shelf
- wide flaring pelvis
What are the 4 synapomorphies of Saurischia?
(1 cranial, 3 post-cranial)
- Lacrimal folds over posterior part of antorbital fenestra
- Hand > 40% of humerus+radius
- Twisted first phalanx in the thumb
- manual digit V lack phalanges
What are the two clades of Saurischia?
Sauropodomorpha, Theropoda
What are the synapomorphies of Saurischia: Sauropodomorpha?
(1 cranial, 2 post-cranial)
- Small skull (< 50% of femur)
- > = 10 cervical vertebrae forming elongate neck
- forelimb > 50% length of hindlimb
What are the 4 key features of Sauropodomorpha: Sauropoda?
(all post-cranial)
- > = 4 sacral vertebrae
- long forelimbs (over 2/3 the length of hindlimb)
- straight femur
- digit V of foot weight-bearing
What are the synapomorphies of Saurischia: Theropoda?
(1 cranial, 2 post-cranial)
- Anterior tympanic recess in braincase
- elongated and curved anterior wing on iliac blade
- MT 1 reduced and attached to MT II, not reach ankle joint
What is the theropod body plan?
(1 cranial, 3 post-cranial)
1, Bipedal gait
2. blade-like serrated teeth
3. s-shaped neck
4. foot with 3 main weight-bearing digits and a short hallux
What are the synapomorphies of Theropoda: Tetanurae
(1 cranial, 1 post-cranial)
maxillary fenestra in antorbital fossa
sharp ridge on tibia for close attachment of fibula
What are the synapomorphies of Theropoda: Tentanurae: Coelurosauria?
(2 cranial, 1 whole body)
- maxilla antorbital fenestra > 40% of external antorbital fenestra
- No serrations on premaxillary teeth
- simple filamentous feathers
What are the 5 common features of herbivorous Coelurosauria?
(3 jaw features)
loss of teeth
toothless beaks
downturned lower jaws
large body size
stomach stones
