Fig. 16.1
Fig. 16.2
Basic Terms Used for Feeding Mechanisms of Vertebrates
1. Suspension-feeding (= filter-feeding) - filter small particles (alive
or dead, depending on species) out of water column
2. Suction-feeding - open mouth, suck in food
3. Ram-feeding - open mouth, swim over food
Ram-Suction Index - compares movement of food relative to
movement of feeder
4. Inertial-feeding - inertia of food is used to move it in oral cavity
5. Transport - movement of food within oral cavity (by water
currents in aquatic vertebrates or tongue in tetrapods)
6. Mastication - physical reduction of food size by chewing
Fig. 16.3
Wear Patterns of Teeth are Functionally Important
Enamel is > 95% inorganic matter; it is the hardest substance in
vertebrate bodies
Enamel is harder than dentine
Dentine is harder than cement
These properties mean that teeth can be “self-sharpening”
Some Important Terms for Teeth
Polyphyodont - multiple generations of tooth replacement (most
vertebrates)
Diphyodont - two sets of teeth: milk and permanent (most
mammals; incisor, canine and premolar teeth are replaced)
Monophyodont - a single set of teeth (e.g., cetaceans)
Homodont - teeth of similar shape along jaw
Heterodont - teeth of different shape along the jaw
Tooth plate or Toothplate - at least two uses are common:
1. Many individual teeth fused together at their bases;
separate cusps are still visible (e.g., in pharynx of fishes)
2. Fusion of individual teeth during ontogeny: separate
cusps may not still be visible (e.g., lungfishes, chimaeras)
Fig. 16.4
Fig. 16.5
Types of Mammalian Teeth and Dental Formulae
Incisor teeth (I), typically these are replaced
Canine teeth (C), typically these are replaced
Premolar teeth (P), typically these are replaced
Molar teeth (M), typically these are not replaced
Formulae are expressed as type # in upper jaw/# in lower jaw
I 5/4, C 1/1, P 2/2, M 4/4 = opossum
I 2/2, C 1/1, P 2/2, M 3/3 = humans
Fig. 16.6
Carnassial Pair: P4-M1
Fig. 16.7
Terms for Mammalian Molars
Tribosphenic molars - plesiomorphic condition seen in
opossums and insectivores
Bunodont molars - low-crowned condition seen in omnivores
such as humans and pigs
Lophodont molars (e.g., Rhinoceros, Fig. 16-9A)
Selenodont molars (e.g., deer, Fig. 16-9B).
Molarization of premolars (remember that premolars are replaced
wheras molars are not replaced.)
High-crowned, or hypsodont, molars (e.g., horse, Fig. 16 -9C).
Fig. 16.8
Teeth of Herbivores
Fig. 16.9
Jaw Mechanics of Actinopterygians 1: Early Actinopterygians
Fig. 16.10
Jaw Mechanics of Sharks
Fig. 16.11
Jaw Mechanics of Actinopterygians 2: Teleosts
Fig. 16.12
Jaw Mechanics of Aquatic Salamanders (Ambystoma)
Fig. 16.13
Cranial Kinesis in Varanid Lizards
Fig. 16.14
Jaw Mechanics of Cats
Fig. 16.15
Jaw Mechanics of Carnivores versus Herbivores
Fig. 16.16
Palates
Fig. 16.17
Tongues
Fig. 16.18
Role of Tongue in Feeding System of Lizards
Fig. 16.19
Salivary Glands
Fig. 16.20
Fig. 16.21
Kinesis and Fang Erection System of Rattlesnakes
Focus 16.1
Kinesis in Beak of Birds
Focus 16.1