[F] Mammals

• Synapsida

  • Amniotes with single temporal fenestrae 
  • Bound by upper temporal bar
  • Formed by squamosal and postorbital 
  • Transition from ectothermy to endothermy 
  • Limbs positioned under the body 
  • Allowed for upright, bipedal locomotion
• Mammalia

  • Late Triassic
  • Key innovations (in extant groups) 
  • Hair 
  • Mammary glands
  • Sebaceous glands
  • Anucleate red blood cells
  • Early forms: small, shrew-like
  • Increases in body size after Mesozoic extinction 
  • Modern vertebrate groups radiated during Cenozoic - diversification
• Mammalian clades:

  1. Monotremes - no external ears, embryos in eggs
  2. Metatheria - young continue to develop in pouches
  3. Eutheria - placental mammals