week 1 lab 2

Two types of hair growth:

Definitive

Angora

Angora

hair grows continuously.

Definitive

shed and replaced once given length reached

Pelage is the total body covering of hair and is comprised of

Vibrissae

Guard hair

Underfur

Vibrissae

Long, stiff hairs that serve as tactile receptors; e.g., whiskers

– Have high blood supply

Guard hair

Awn

Bristles

Bristles

firm hairs with angora growth; e.g., lion mane. May be

stiff/enlarged such as the spines/quills on porcupines, hedgehogs,

echidnas, and “spiny mice.”

Awn

(most common) outer layer of hair on most mammals. Exhibit

definitive growth - expanded distally, weakened basally.

Underfur

two types:

– Wool

– Fur

– Fur

relatively short, with definitive growth.

Wool

long, soft, often curly with angora growth.

bottom = underfur

top = guardhairs

vibrasse

epidermal scales

Molt is

the process of replacing some or all of an animal’s fur.

Post-juvenile molt

juvenile pelage  adult pelage.

Annual molts

replaces hairs that are worn.

Seasonal molts

summer vs. winter; i.e., for camouflage.

Directional terms for skull: label

Cusps

Upper teeth

Trigon:

– protocone

– metacone

– paracone

– hypocone

Cusps

Lower teeth

Trigonid:

– protoconid

– metaconid

– paraconid

– hypoconid

– entoconid

– talonid *know this for tribosphenic molars

Occlusal Patterns

• dilamdodont

• quadrituberculate

• lophodont

• selenodont'

• secodont

type of pattern

ZALAMBDODONT

type of pattern

DILAMBDODONT

SELENODONT

LOPHODONT

Specialized Teeth

• Bunodont

• Carnassials

• Plagiaulacoid

Plagiaulacoid

grinding vegetation;

third premolar (PM3, pm3).

– Found in marsupials

Carnassials

shearing bad boys; a type of

secodont; fourth upper premolar, first lower

molar (P4/m1 – know this!)

Bunodont

low, rounded cusps for crushing

molar power.

– Found in omnivores

Tooth Crown Height

Brachydonty → low crowned

– e.g., humans, bears, pigs.

• Hypsodonty → high crowned

– e.g., kangaroo rat, deer, horse

Incisor procumbancy

proodont

Incisor procumbancy

orthodont

Incisor procumbancy

opisthodont

Horns

● Bony core covered by keratin

sheath (also called bone)

● Unbranched

● Permanent, with

indeterminate growth

● Projection of frontal bone

● Found on males; sometimes

on females

○ larger on males

Pronghorn

● Similar to horns, but

with a prong

● Shed annually

● Projection of frontal

bone

● May be found on

both sexes, but as

with horns, larger on

males

Antlers

● Found only on males

● Exception: female caribou

have antlers

● Solid bone; when growing,

covered by velvet (living

skin, fur)

● Shed annually

Branched: know/label 5 parts

burr, browtine, mainstem, and crown

Ossicones

Horn-like structures formed within the skin; secondarily fuse to

skull (over fronto-parietal suture)

● Found in both sexes; remain furred in females, not males

● Giraffe and okapi

Rhinos

have “horns” but these are not bony. They are agglutinized hairs.

three cusps of the upper molar together are called the

trigon

three cusps of the lower molar combined are called the

trigonid

Dilambdont (W shape)

Euthemorphic/Quadritubercular (four main cusps)

Lophodont (note rounded corners)

Bilophodont (two lophs)

Selenodont (note sharp corners)

Bunodont (rounded and bumpy)