FW4240 Mammalogy Lecture Exam 1

Taxonomic orders within the Mammalian class for MTU FW4240 Mammalogy Fall 2026

Class

Mammalia

Subclasses

Prototheria and Theria

Infraclasses

Metatheria and Eutheria

Metatheria

Marsupials

Eutheria

Placentals

Superorders

Afrotheria, Xenarthra, Euarchontoglires, Laurasiatheria

Order within Prototheria

Monotremata

Number of Prototherian species

~5

Monotremata

Platypus, echidna

How many studied orders are in Metatheria?

7

Number of Metatherian species

~400

American Metatherian Orders

Didelphimorphia, Paucituberculata, Microbiotheria

Didelphimorphia

Opossums

Paucituberculata

Shrew opossums

Microbiotheria

Monito del monte

Australian Metatherian Orders

Diprotodontia, Dasyuromorphia, Notoryctemorphia,

Diprotodontia

Wombats, koala, kangaroos

Dasyuromorphia

3 families of marsupial carnivores - Thylacine, tasmanian devils

Notoryctemorphia

Marsupial moles

Peramelemorphia

Bandicoots and bilbies

How many studied orders are in Eutheria?

19

Number of Eutherian species

~6,400

Afrotherian Orders

Afrosoricida, Macroscelidea, Tubulidentata, Hyracoidea, Proboscidea, Sirenia

Afrosoricida

Tenrecs, golden moles

Macroscelidea

Elephant shrews

Tubulidentata

Aardvarks

Hyracoidea

Hyraxes

Proboscidea

Elephants

Sirenia

Manatees, dugongs

Xenarthran Orders

Cingulata, Pilosa

Cingulata

Armadillos

Pilosa

Sloths, anteaters

Euarchontoglires Orders

Rodentia, Lagomorpha, Scandentia, Primates, Dermoptera

Rodentia

Rodents

Lagomorpha

Rabbits, hares, pikas

Scandentia

Tree shrews - SE Asia

Primates

Monkeys, apes, humans

Dermoptera

Flying lemurs - SE Asia

Laurasiatherian Orders

Eulipotyphla, Chiroptera, Carnivora, Pholidota, Perissodactyla, Cetartiodactyla

Eulipotyphla

Shrews, moles, hedgehogs

Chiroptera

Bats

Carnivora

Carnivores

Pholidota

Pangolins - Africa, SE Asia

Perissodactyla

Odd-toed ungulates (horses, tapirs, rhinos) - SA, EU, SE Asia, Africa

Cetartiodactyla

Cetaceans (whales, dolphins) and even-toed ungulates (deer, pigs, giraffes)

4 mammalian soft anatomy characteristics that support high metabolic rates

4-chambered heart for separation of de/oxygenated blood, enucleated red blood cells to allow for more oxygen circulation, muscular diaphragm to increase ventilation of lungs, absence of a renal portal system increasing efficiency of circulation and raising blood pressure

Major soft anatomy characteristics of mammals

Hair, mammary glands, complex integumentary system, endothermy, viviparity, 4-chambered heart, muscular diaphragm, enucleated red blood cells, nitrogenous waste, increased facial muscles, larger brains

Major hard anatomy characteristics of mammals

Double occipital condyles, single dentaries, dentary-squamosal jaw articulation, three middle-ear ossicles, tympanic bone, heterodont and diphyodont dentition, thoracic-only ribs, a hard secondary palate, calcaneus, phalangeal formula, and reduced shoulder girdle

Double occipital condyles (functional purpose)

Strengthens contact with the vertebral column while allowing for flexion in two planes. Only found in mammals

Single dentaries (functional purpose)

Reduction of number of bones provides structural strength to the lower jaw. (1) Only found in mammals

Dentary-squamosal jaw articulation (functional purpose)

Creates a strong hinge joint to allow for stronger biting and chewing abilities. Only found in mammals

Three middle-ear ossicles (functional purpose)

Amplify and transmit sound vibrations to the inner ear. Remnants of extra dentaries

Tympanic bone (functional purpose)

Anchors and protects the eardrum

Heterodont dentition (functional purpose)

Allows specialization of teeth for various styles of eating and thus varied diet

Diphyodont dentition (functional purpose)

Multiple sets of teeth to increase period of life with teeth, keep precise bite alignment

Thoracic-only ribs (functional purpose)

Enhances trunk flexibility for agile locomotion

Hard secondary palate (functional purpose)

Separates the oral cavity from the respiratory passage, allowing breathing while eating

Calcaneus (functional purpose)

Extra mechanical lever for calf muscle to create more force for locomotion

Mammalian phalangeal formula (functional purpose)

Standardizes digit counts to $2\text{-}3\text{-}3\text{-}3\text{-}3$ to increase mechanical stability and dexterity during weight-bearing.

Reduced shoulder girdle (functional purpose)

Fewer but weaker bones that increase mobility

Homology

Homoplasy

Synapomorphy

Symplesiomorphy