Dinosaur Classification Flashcards

Dinosaur Classification Notes

• Theropods

  • Characterized by laterally compressed serrated teeth.
  • Have three forward-pointing toes and one backward-pointing toe.
  • Possess hollow bones with thin but dense walls.

• Allosauroids

  • A type of theropod with three claws and three fingers on each hand.
  • Features medium tooth serrations and long legs for slashing bites.
  • Possesses long caudal zygopophyses, providing tail stiffness.

• Ceratosauroids

  • Identified as a theropod with three claws and four fingers on each hand.
  • Exhibits fine tooth serrations and longer teeth.
  • Characterized by a long tail, very short legs, and horned snouts.

• Megalosauroids

  • Another theropod type with three claws and three fingers on each hand.
  • Notable for large tooth serrations and bulky body structure.

• Coelurosaurs

  • Small theropods from the Jurassic period, featuring numerous sacral vertebrae.
  • Have a long tibia and include both raptors and modern birds.

• Ornithischians

  • Notable for a predentary bone and opisthopubic pelvic structure.
  • Characterized by ossified tendons.

• Thyreophorans

  • Known as "shield bearers" among ornithischians.
  • Possess osteoderms (bony armor) embedded in their skin.
  • Include two major varieties: stegosaurs and ankylosaurs.

• Ornithopods

  • A group of ornithischians, mostly bipedal.
  • Have a chewing mouth structure, varying in size from small to gigantic forms.

• Iguanodontids

  • Medium to large ornithopods with specialized chewing teeth.
  • Identifyable by a spiked thumb claw and are ancestors to hadrosaurs.

• Sauropods

  • The largest terrestrial animals, equipped with pneumatic bones filled with air sacs.
  • Known for simple teeth structure.

• Diplodocids

  • A sauropod subtype with long whip-like tails.
  • Teeth are located only at the front of the mouth, with minimal claws on front feet.
  • Proportionately gracile in form.

• Macronarians

  • Characterized by larger teeth and nasal openings bigger than their orbits.
  • Generally robust in structure.

• Hadrosaurs

  • Known as duck-billed dinosaurs, evolved from iguanodontids.
  • Feature complex dental batteries and are facultatively bipedal.

• Ankylosaurs

  • Possess large ribcages for digestive capacity and backs covered in osteoderms.
  • Adapted for low grazing with simple teeth and armored skulls.

• Ankylosaurids

  • A subset of ankylosaurs with short, broad snouts and small horns.
  • Distinguished by tail clubs.

• Nodosaurids

  • Another ankylosaur variant with longer, more narrow snouts and lack of tail clubs.

• Pachycephalosaurs

  • Bipedal dinosaurs with armored skulls and large domes.
  • Feature bracing tails for support.

• Ceratopsians

  • Noted for their frills which elongate skulls to form neck shields.
  • Recognized for dental batteries, horns, and unique rostral bones.

• Tyrannosaurids

  • Characterized by reduced arm size, wide skulls, and robust teeth.
  • Possess long legs and a distinctive arctometatarsal foot structure.