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. 16.6Carnassial 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

Fig. 16.9

Teeth of Herbivores

Fig. 16.10

Jaw Mechanics of Actinopterygians 1: Early Actinopterygians

Fig. 16.11

Jaw Mechanics of Sharks

Fig. 16.12

Jaw Mechanics of Actinopterygians 2: Teleosts

Fig. 16.13

Jaw Mechanics of Aquatic Salamanders (Ambystoma)

Fig. 16.14

Cranial Kinesis in Varanid Lizards

Fig. 16.15

Jaw Mechanics of Cats

Fig. 16.16

Jaw Mechanics of Carnivores versus Herbivores

Fig. 16.17

Palates

Fig. 16.18

Tongues

Fig. 16.19

Role of Tongue in Feeding System of Lizards

Fig. 16.20

Salivary Glands

Fig. 16.21

Focus 16.1

Kinesis and Fang Erection System of Rattlesnakes

Focus 16.1

Kinesis in Beak of Birds