Mammalogy Lab 16 Rodentia 2

Order <strong>Rodentia</strong><br />

Part II<br />

Myomorphous Groups<br />

• infraorbital canal size variable<br />

• angular process not deflected<br />

• lateral masseter connects to zygomatic arch<br />

• 2-4/2-4 cheekteeth<br />

medial masseter<br />

lateral masseter<br />

1

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• short tail<br />

Geomyidae – Gophers<br />

• external cheek pouches<br />

• 2 pits between last upper molars<br />

• premolar 8-shaped, larger than molars<br />

• 4 cheekteeth<br />

Heteromyidae – Pocket Mice,<br />

Kangaroo Rats, etc.<br />

• long tail, may be tufted<br />

• long hindlimbs<br />

• external cheek pouches<br />

• inflated auditory bullae<br />

• 4 cheekteeth<br />

• cheekteeth crowns simple, 2-lobes<br />

2

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• bushy tail<br />

Gliridae – Dormice<br />

• infraorbital canal maybe V-shaped<br />

• 4/4 cheekteeth<br />

• cheekteeth crowns low with transverse ridges<br />

Dipodidae – Jumping Mice & Jerboas<br />

*note that this family now includes Zapodidae<br />

• long tail<br />

• large oval infraorbital canal<br />

• 3-4 upper cheekteeth, 3 lower cheekteeth<br />

3

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Cricetidae – New Wolrd Mice, Voles,<br />

Hamsters, Muskrats, and relatives<br />

• infraorbital canal V-shaped<br />

• 3 cheekteeth<br />

• cheekteeth crowns usually with 3 cusp rows<br />

Muridae – Old World Mice, Rats,<br />

Gerbils, and relatives<br />

• infraorbital canal V-shaped<br />

• 2-3 cheekteeth<br />

• cheekteeth crowns usually with 3 cusp rows<br />

4