Chapter 13 Part 4 Flashcards
Where are teeth found in: mammals, crocodilians, lizards
Teeth restricted to premaxilla, maxilla (upper) and dentary (lower)
Where are teeth found in teleosts
- they have pharyngeal teeth
- Teeth attached to pharyngeal jaw, back in throat behind premaxillary and lower jaw
- May be formed for grasping, tearing, grinding, or combing(depends on prey type)
- Have outer and inner rows
- Teeth in patches: permaxillary patch, vomerine patch, and maxillary patch
Where are teeth found in amphibians?
Some have vomerine teeth, pair found on upper palate/jaw
Where are teeth found in snakes?
In addition to maxilla and lower jaw, also have vomer, palatine, and pterygoid teeth
Diphyodont
2 sets of teeth(mammals)
Polyphyodont
constant replacement throughout life (all other vertebrates with teeth)
Thecodont
attachment in sockets
Seen in mammals, crocodilians toothed birds, and dinosaurs
Replacement tooth grows up under/within baby tooth
Acrodont
attached to the rim of mouth/gums
Seen in some amphibians, lizards, and tuatara
Replacement tooth bent behind active tooth
Pleurodont
attached to inner(lingual) surface
Seen in some amphibians, lizards, and snakes
Side is attached to mouth/gum
replacement tooth within baby tooth
Homodont teeth
Most vertebrates: all teeth the same shape
Development: Teeth before metamorphosis (larval) and after metamorphosis (adult) in northwestern salamander (Ambystoma gracile)
Larval teeth pointed
Those of the transformed adult have divided cusps that sit on a basal pedicel
The cusps are thought to inflect with the struggling prey, thus resisting its escape from the mouth
Heterodont teeth
specialized teeth
From front to back: incisors, canines, premolars, molars
Describe the difference between heterodont and homodont teeth
Homodont teeth all have the same shape, while heterodont teeth are not; they are specialized generally into four categories
Which term of teeth characterizes mammals?
heterodont teeth!!
Incisors
Anterior teeth – typically spatulate
Used as pincers for grasping or picking, both in feeding and in grooming
Rodent incisors
▪ Large, chisel-like
▪ Rootless and grow continuously
Lemur incisors
▪ Have elongated lower incisors, called strehsirrhine
▪ Use elongated lower incisors as grooming device, social activity/bonding
aye-ayes incisors
▪ Pair of lower and upper incisors that continuously grow; rootless
▪ Specialized insectivores, similar to woodpeckers in feeding
elephant incisors
enlarged upper tusks are incisors!!
What various groups lack parts of incisors?
▪ Bovids(cows): no upper incisors
▪ Vampire bats: no lower incisors
▪ Sloths: no incisors
