Memory Aid Key to the Skulls Small to Medium




Дата канвертавання15.04.2016
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Memory Aid Key to the Skulls
Small to Medium
Medial diastema in upper jaw - Chiroptera, Vespertilionidae (bats)

Pointed rostrum - Insectivora

Pigmented teeth - Soricidae (shrews)

White teeth - Talpidae (moles)

Canines present - Carnivora, Mustelidae (mink, skunk, etc.)

Canines absent

Rostrum fenestrated - Rodentia

Infraorbital foramen dorsal

4 upper cheek teeth - Zapodidae (jumping mice)

3 upper cheek teeth

Molar surfaces flat, skull flat in side view

Surfaces composed of triangles - some Cricetidae

(voles, muskrat)

Molar surfaces with cusps

Cusps in 2 rows - some Cricetidae (native rats, mice)

Cusps in 3 rows - Muridae (Old World rats, mice)

Infraorbital foramen ventral

Molars with cusps, skull oval - Sciuridae (squirrels, chipmunks)

Molar surfaces lamellate, skull flat - Geomyidae (pocket gopher)
Large
Canines present

Rostrum short - Carnivora

5 lower cheek teeth - Mustelidae (skunk, badger)

3 lower cheek teeth - Felidae (cats)

Rostrum long

Prominent sagittal crest - Marsupialia, Didelphidae (opossum)

No sagittal crest - Carnivora

Carnassial teeth present - Canidae (fox)

Carnassial teeth absent - Procyonidae (raccoon)

Canines absent

Rostrum fenestrated - Lagomorpha, Leporidae (rabbit)

Rostrum not fenestrated - Rodentia

Large infraorbital foramen

Long processes at angle of jaw and on occipital bone - Capromyidae (nutria)

No such processes - Erethizontidae (porcupine)

Small infraorbital foramen

5 upper cheek teeth - Sciuridae (woodchuck)

4 upper cheek teeth - Castoridae (beaver)


Very Large
Upper canines present

Short rostrum - Carnivora, Ursidae (bear)

Long rostrum

Upper incisors pointed laterally - Artiodactyla, Suidae (pig)

Upper incisors pointed ventrally - Perissodactyla, Equidae (horse)

Upper canines absent

Upper incisors present - Rodentia, Castoridae (beaver)

Upper incisors absent - Artiodactyla

Conchae exposed laterally - Cervidae (deer)

Conchae not exposed - Bovidae (cow, sheep)


Glossary
antorbital plate - the sheet of bone that forms the front wall of the eye socket
carnassial teeth - the last upper premolar and the first lower molar of certain Carnivora arranged so as to produce a shearing action as the mouth is closed
cheek teeth - the premolars and molars considered together
conchae - the scroll-like bones seen in the nasal cavity
cusps - bumps on the surfaces of the premolars and molars
diastema - a gap between teeth in the tooth row
infraorbital foramen - a passageway in the antorbital plate connecting the orbit to the side of the rostrum
orbit - the eye socket
palate - the roof of the mouth
rostrum - the portion of the skull extending forward from the orbit
tympanic bulla - a usually hemispherical bulb containing the auditory apparatus
zygomatic arch - the bar or plate of bone forming the lateral rim of the orbit


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