Lecture 5: teeth morphology
Dentition = interface between the animal and its surroundings. It is important because:
- It shows adaptation to different diets
- It is useful for palaeoecological interpretations
- Teeth fossilize well
- It can be used as a stratigraphic tool
Different kinds of information of tooth:
- Microwear shows something about the sort of food
and the way it is processed.
- Tooth replacement: some animals replace teeth (e.g.
mesosaurs and reptiles). The time it takes differs
between taxa (e.g. each year).
- Migration: the isotopes 87Sr/86Sr have different values in
different environments and thus show something
about where an animal lived.
- Bones: show the calcium signature. Big, sharp tooth are
needed for crushing bones.
- Body temperature: clumped isotopes
- Diving: you can use different techniques to reconstruct
characteristics of animals (e.g. isotope signature and
diet).
- Bite force: differs in different animal and can be
reconstructed.
- Prey capture: the jaw can be shaped for specific kinds
of prey that can be captured.
Tooth exist 97% of hard stuff (enamel) and 3% of softer, more porous and less persevered dentine.
In mammals it is more complex:
- Original mammalian dental formula and molar pattern (tribosphenic) is the basis. The
evolutionary directions (adaptations) are knows and thus relationships between mammal
taxa can be reconstructed based on the dentition.
- Homodont has the same teeth everywhere in the mouth and heterodont has a specialisation
from front to back: incisors, canine, premolars and molars.
- The dental formula is I/I, C/c,/ P/p, M/m
For placental mammals: 3/3. 1/1. 4/4. 3/3.
Humans: 2/2. 1/1. 2/2/ 3(2)/3(2)
Hamster: 1/1. 0/0. 0/0. 3/3.
- Examples and terminology is in the PowerPoint
, Lecture 6: Vertebrates
Taphonomy = the history of fossilization from the moment an organism (animal or plant) dies until
the moment its fossil is being collected.
We only have a tiny fraction available of former biocoenosis. Loss of information because:
- Not all dead animals can fossilize
- Not all dead animal that can, will fossilize
- Many then get lost during the geological history
- Many are never found (e.g. too deep)
- Many are neither well collected or kept.
Sources of information
- Bones: big ones are more common
- Teeth
- Skin imprints (also like feathers)
- Gastrolites: stones that are eaten by animals
to act like molars
- Bite marks: trace fossil
- Dung: shit
- Eggs
- Nests
- Embryos
- Tracks
Taphonomy:
- Small versus large animals
- Biotransport: accumulation by predators (owls, hyanenas or their ectomorphs)
- Many more associations of small animals than of large
- Selective sorting (e.g. by water and redepostion)
- Difference in localities (layered, karstic, anoxic, Lagerstatten)
- Variations in collecting techniques (washing)
Large mammals (all except small mammals, Small mammals (order Rodentia, Insectivora,
rodents, insectivores, bats and rabbits) Chiroptera, Lagomorpha)
Postmortal loss of bones and teeth is normal Many post burial events as with large
ans a result of: mammals, but more often we observe
- Dissolution (chemical) biotransport and bioaccumulation by raptors
- Erosion (e.g. through roots) (regurgitation pellets) or (small) carnivores
- Biotransport (moving, trampling) (faecal remains). This is recognizable by
- Reworking/transport within the dissolution and has consequences for using
sediment (mixing of assemblages) relative amounts
Locations:
1. Layered deposits (channel, flood plain, lake sediments, lignites): usually have a certain
stratigraphy, dating methods are sometimes possible, long term faunal succession and
reliable correlations.
2. Karst and caves (cave deposits, fissure fillings): are often well persevered material, complete
articultated skeletons, only biostratigraphic correlation is possible so no good dating at most
short faunal succession (Jankovitch)
3. Exceptational preservations: anaerobic circumstances (Messel), permafrost (mammoths), salt
deposits (gypsum form Montmarte), tar seeps (Rancho la Brea) and foot prints
Dentition = interface between the animal and its surroundings. It is important because:
- It shows adaptation to different diets
- It is useful for palaeoecological interpretations
- Teeth fossilize well
- It can be used as a stratigraphic tool
Different kinds of information of tooth:
- Microwear shows something about the sort of food
and the way it is processed.
- Tooth replacement: some animals replace teeth (e.g.
mesosaurs and reptiles). The time it takes differs
between taxa (e.g. each year).
- Migration: the isotopes 87Sr/86Sr have different values in
different environments and thus show something
about where an animal lived.
- Bones: show the calcium signature. Big, sharp tooth are
needed for crushing bones.
- Body temperature: clumped isotopes
- Diving: you can use different techniques to reconstruct
characteristics of animals (e.g. isotope signature and
diet).
- Bite force: differs in different animal and can be
reconstructed.
- Prey capture: the jaw can be shaped for specific kinds
of prey that can be captured.
Tooth exist 97% of hard stuff (enamel) and 3% of softer, more porous and less persevered dentine.
In mammals it is more complex:
- Original mammalian dental formula and molar pattern (tribosphenic) is the basis. The
evolutionary directions (adaptations) are knows and thus relationships between mammal
taxa can be reconstructed based on the dentition.
- Homodont has the same teeth everywhere in the mouth and heterodont has a specialisation
from front to back: incisors, canine, premolars and molars.
- The dental formula is I/I, C/c,/ P/p, M/m
For placental mammals: 3/3. 1/1. 4/4. 3/3.
Humans: 2/2. 1/1. 2/2/ 3(2)/3(2)
Hamster: 1/1. 0/0. 0/0. 3/3.
- Examples and terminology is in the PowerPoint
, Lecture 6: Vertebrates
Taphonomy = the history of fossilization from the moment an organism (animal or plant) dies until
the moment its fossil is being collected.
We only have a tiny fraction available of former biocoenosis. Loss of information because:
- Not all dead animals can fossilize
- Not all dead animal that can, will fossilize
- Many then get lost during the geological history
- Many are never found (e.g. too deep)
- Many are neither well collected or kept.
Sources of information
- Bones: big ones are more common
- Teeth
- Skin imprints (also like feathers)
- Gastrolites: stones that are eaten by animals
to act like molars
- Bite marks: trace fossil
- Dung: shit
- Eggs
- Nests
- Embryos
- Tracks
Taphonomy:
- Small versus large animals
- Biotransport: accumulation by predators (owls, hyanenas or their ectomorphs)
- Many more associations of small animals than of large
- Selective sorting (e.g. by water and redepostion)
- Difference in localities (layered, karstic, anoxic, Lagerstatten)
- Variations in collecting techniques (washing)
Large mammals (all except small mammals, Small mammals (order Rodentia, Insectivora,
rodents, insectivores, bats and rabbits) Chiroptera, Lagomorpha)
Postmortal loss of bones and teeth is normal Many post burial events as with large
ans a result of: mammals, but more often we observe
- Dissolution (chemical) biotransport and bioaccumulation by raptors
- Erosion (e.g. through roots) (regurgitation pellets) or (small) carnivores
- Biotransport (moving, trampling) (faecal remains). This is recognizable by
- Reworking/transport within the dissolution and has consequences for using
sediment (mixing of assemblages) relative amounts
Locations:
1. Layered deposits (channel, flood plain, lake sediments, lignites): usually have a certain
stratigraphy, dating methods are sometimes possible, long term faunal succession and
reliable correlations.
2. Karst and caves (cave deposits, fissure fillings): are often well persevered material, complete
articultated skeletons, only biostratigraphic correlation is possible so no good dating at most
short faunal succession (Jankovitch)
3. Exceptational preservations: anaerobic circumstances (Messel), permafrost (mammoths), salt
deposits (gypsum form Montmarte), tar seeps (Rancho la Brea) and foot prints
