Chapter 4 “Reptile”
Feldhamer Table 4.1 Savage and Long 1986
Fig. 3.2, Vaughn, Fig. 4.1,Feldhamer
Overview Synapsids Pelycosaurs and Therapsids First Mammals Mesozoic Era appear Cenozoic Era radiate
Major groups of Synapsida
Feldhamer Fig. 4.2Savage and Long 1986
Skull, jaw musculature, and teeth
Cynodontia -- Advanced, predaceous therapsids
DerivedTherapsid/Mammal Late Cynodont
Fig. 3.2, Vaughn
Fig 4.3 & 4, Feldhamer
Pelycosaur Fig. 4.15Extinction of Cynodonts
Possibly competition from dinosaurs Early Cynodonts were dog-size, last surviving were squirrel sized Mammals that survived while Cynodonts went extinct (contemporary) weremouse-sized.
Fig. 3.5, Vaughn
Fig. 4.16c, Early Cynodont
200 - 250 million years ago Derived characters: Dentary/squamosal jaw articulationDiphyodont dentition Mammary glands Secondary palate Viviparity (loss of eggshell) When?
Changes in land masses
180 MYA MidJurassic
200 MYA Early Jurassic
135 MYA EarlyCretaceous
Feldhamer 4.5, 4.9
65 MYA Early Cenozoic
Skull and teeth of mammals
Teeth and Dentition of Mammals
One of the major keys to success ofmammals Teeth of mammals are extremely variable with different diets -more than other taxa
Heterodont teeth with different functions Differentiated on the basis of function, resulting in increasedefficiency acquiring and digesting food. Teeth occur in 3 bones of skull: premaxilla, maxilla, dentary
Feldhamer et al.
Additional Notes on Tooth Structure Not all teeth have enamel over entire...