Biol 425, Mammalogy




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BIOL 425, Mammalogy

Skull and Dental Characteristics & Introduction to Orders of Mammals

Oct. 5, 2010
1. Skull (handout Ch. 2) – Be able to locate and identify the principle bones of the skulls. Handouts will go into depth and provide you with information needed to key out the Orders of living mammals. In the handout, it’s OK to scan over Determination of Maturity and Measurements sections. We will cover these topics later.
Regardless of the Order that the skull belongs to, know these:

Cranium


Mandible – right and left dentary bones, body, and ramus

Occipital condyles

Auditory bullae

Orbit


Temporal fossa

Squamosal

Jugal

Zygomatic processes: squamosal and maxilla



Premaxillae

Maxillae


Palatine

Foramen magnum

Coronoid process

Nares
2. Dentition (handout Ch. 3) –Examine several skulls from different orders. Identify: incisors, canines, pre-molars, and molars. Can you differentiate between a premolar and a molar? (Not as easy as it sounds!). In the handout, it’s OK to scan over the tooth anatomy and replacement, but you may need to refer to this section when keying.


Spend some time looking at the different types of dentition:

Lophodont – what are lophs good for?

bunodont – how many cusps on these teeth?

Selenodont – how do these teeth differ from lophodont? Which wears faster?

hypsodont – how do these teeth differ from brachydont?

Brachydont – how de these teeth differ form hypsodont?

secodont – what do species with this type of dentition eat?
2.1 Dental formula – number of each kind of teeth in an animal

Know the dental formula and how to interpret it. Because the premolars and molars are sometimes impossible to distinguish, these teeth are sometimes grouped in the formula. Check with your classmates to see if you are getting formulas correct. If you still are unsure, Dash or I will try to give you a hand.


3. Keys and keying (handout Ch. 8)

It is OK to give this handout a quick read, but understand why Mammalogists key and how they select the characteristics included in a key.


4. Keying the Orders (handout Ch. 9)

Hopefully, you will be able to spend most of lab keying out the Orders. Skulls of nearly all Orders that we will learn about in this class are on display. This we reinforce what you learned about in the previous handouts. Know which Orders fit into which subclasses (Prototheria & Theria). Theria is divided into 2 infraclasses (Metatheria & Eutheria). The differences between the subclasses is largely based on reproductive anatomy and reproduction modes. The differences between the infraclasses is largely based on how offspring are nourished prior to and following birth.


Be able to identify the order of each skull. The table provided below is to confirm your “keying” skills. I recommend that you test yourself. Key the skulls on display and then go back and see how well you did.


Order

Common name

Cetacea

Hubb’s beaked whale, Amazon dolphin

Monotremata

Platypus, echidnas

Pholidota

Pangolins

Xenartha

Anteaters, armadillo, sloths

Primates

Gorilla, red-ruffed lemur, chimpanzee

Tubulidentata

Aardvark

Didelphimorphia

Opossums

Diprotodontia

Koala, red-necked wallaby, red kangaroos

Hyracoidea

Rock hyrax

Insectivora

Cuban Solenodon, Eurasian hedgehog

Macroscelidia

Elephant shrew

Lagomorphs

Snowshoe hare, Nuttall’s cottontail rabbit

Rodentia

Capybara, beaver, arctic ground squirrel

Sirenia

Manatees

Scandentia

Tree shrews

Dermoptera

Flying lemur

Chiroptera

Vampire bat, fish-eating bat

Perissodactyla

Brazilian tapir, zebra, horse

Artiodactyla

Babiruso, giraffe, pygmy hippo

Carnivora

Wolf, lynx, coyote, elephant seal, hyena,

Dasyuromorphia

Numbat, Tasmanian wolf & devil


HAVE FUN!!!


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