Mammal
Where was the original metatherian/eutherian divergence? What are the three primary metatherian clades?
Asia. Ameridelphia, Australidelphia, and Deltatheroidea,
Why is precise occlusion and a diphyodont dentition impotant to suckling? Who pointed this out?
Polyphyodont teeth won't occlude perfectly until fully erupted. Need for precise occlusion means only one set of permanent teeth = diphyodont. Diphyodont (and reducing tooth sets) = liquid food so jaw can grow while teeth not necessary, until permanent teeth erupt. (= For precise occlusion, they need one set of permanent teeth which won't happen until teeth have fully erupted) Pond!
What was the longest surviving mammal clade (now extinct?)
allotherians, multituberculates
Are flying squirrels altricial or precocial?
altricial
The opossum belongs in which clade?
ameridelphia
What is myrmecophagous?
anteaters
What taxa are included in Xenarthra?
anteaters, sloths, armadillos
How do antlers and horns differ?
antlers=bony outgrowths, in males, velvet, branch, shed horns= bony core, keratin sheath, not shed, both sexes, no branching
What are the Dermoptera?
arboreal gliders
Explain sloths
arboreal, Eats buds, shoots, and leaves. Large, compartmentalized, slow stomach; digestion takes a month. Bacteria feeds on fur. Move only when need to, slow. Hang on tree with claws. Come down to pee once a week.
Scandentia fall into what clade?
archonta,
Which is the only species in N. America of armadillo
banded
What taxa are members of Peramelina?
bandicoot & bilbie
How can you distinguish between a bandicoot and a bilbie? Which look like "Australian marsupial rabbits?"
bandicoot-shorter legs, & bilbie, bilbie
Did synapsids radiate before or after diapsids?
before
what is the largest mammal
blue whale
What were the diprotodontians? What taxa fall into this group? What are the three main subclades discussed in class (know where the taxa fit)?
branch of australian marsupials, vombatiformes (wombat koala) phalangeriformes (possum) macropodiformes (kangaroo, wallabee)
What are some of the problems associated with muroids?
can cause food losses, carry pathogens
What are the clades and subgroups within Ferungulata?
carnivora, pholidota, perissodactyla, artiodactyla, cetacea
Which therapsid lineage gave rise to mammals? What happened to the rest of them? When?
cynodonts; went extinct during the end-permian
What are the three main clades of Australidelphia? Which taxa belong in these groups?
dasyuromorphia (marsupial cat/mice, tasmanian); peramelina (bandicoots, bilbies); diprotodontians (thylacoleo)
What features characterized theriodonts?
developed coronoid on dentary, flange near lower back jaw, larger temporal fenestra
Describe the wing of a chiropteran
digits with webbed membrane
Which of the three main subclades does a wombat fall into?
diprotodontians
What subclade does a kangaroo fall into? What is the main distinction between a wallaby and a kangaroo?
diprotodontians; kangaroo is larger with longer legs
Discuss climate shifts and ice ages during the Quaternary?
drastic cooling & climate fluctuation; 4 major, 20 minor ice ages, continental glaciers spread, ranges of plants & animals shifted towards equator, glaciers retreated 15k years ago
What are some typical characteristics of myrmecophagous taxa?
elongate jaws, reduced teeth, enlarged salivary glands, elongated tongue
What are the key features that link Pelycosaurs to more derived therapsids?
enlarged canine in maxillary bone, arched palate, flange on angular bone
What are the three primary radiations of Boreoeutheria?
euarchontoglires; laurasiatheria, ferungulata
What were borhyaenids?
extinct didelphoids
What is coprophagy and why is it necessary?
feeding on poop, get more nutrition such as b12 (no complex digestive)
What trait groups chiropterans in a category with birds and pterodactyls?
flight
What major change took place in the FLORA of the Cenozoic? How did the climate shift from the Eocene-Oligocene? What happened in the Miocene?
flowering plants came to dominate in forests except in cool regions; hot & humid at the beginning, cooler & drier halfway through
incisor
front teeth used for cutting, cropping, in rodent/tusks/horn/beaver; carnivores, many taxa (deer, tiger, pig)
What is the diet of most megachiroptera?
fruit
Name 2 myrmecophagous taxa in different clades.
giant anteater, silky anteater
What was diprotodon? What did he eat?
giant wombat, grazer of shrubs etc
Why would lactation be a selective advantage?
glands already secreting to protect eggs in nest; mutations that provided additional nutrients (fat, calories) were selected for
What are the clades and subgroups within Euarchontoglires?
glires, archonta
Be able to list/recognize the features of extant mammals
hair, mammary glands, live birth, dentary/squamosal jaw joint, large brain, large inner ear region, 3 ear bones, post canine teeth with divided roots, endotherms
What are the differences between a rabbit and a hare?
hares change color, have precocial young, simple nests but rabbits altricial, in colonies & dig burrows
Why are they called flying foxes?
have faces that resemble foxes or dogs
Why are rabbits able to move so fast?
have long legs & flexible backs
Lipotyphla includes what taxa?
hedgehogs, moles
Describe the feeding habits of a koala
herbivorous- eucalyptus
Name two of the smallest mammals
hog-nosed bat, etruscan shrew
How do rodent incisors self-sharpen?
inner surface sharper than outer enamel and wear away faster to create a sharp edge
What do most bats eat?
insects
Give 2 ways microchiroptera differ from megachiroptera.
lack under-fur, lack a claw on 2nd digit
Glires includes what two groups of taxa?
lagomorpha, rodentia
Give 10 derived features for therapsids (you'll be asked to list ~4, recognize all).
larger temporal fenestra, skull rigid, heterodont, longer upper canine, flexible neck, girdles lighter, limbs slender, longer stride, vascularized bones, trough in roof of mouth, enlarged choanae
What is the capybara? Which subclade is he in?
largest rodentia, caviidae like guinea pig
When (what eras AND how many years ago?) were mammals most abundant?
late carboniferous & permian
When did mammals first appear
late triassic/mesozoic
What are the clades and subgroups within Laurasiatheria?
lipotyphla, chiroptera
What is unusual about Xenartha metabolic rate?
lowest metabolism
heterodont vs homodont:
mammals have heterodont. We have molars, premolars, canines, and incisors
Provide the characteristics of a beaver and why this taxon may have a disproportionate effect on an ecosystem.
mate for life, have fam; medium size, semiaquatic, flat tail, webbed feet; herbivorous, build lodge (dams) which can create lakes & new habitat
How do Dermoptera differ from flying squirrels?
membrane extends through body and not just limbs
Which clade do vampire bats fall into?
microchiroptera
Which group of chiropterans echolocates?
microchiroptera
What are the only eusocial mammals?
naked mole rats
Describe/recognize the distinctive features of the mole-rat.
naked, blind, suckled for 4 weeks, fed poop by workers, no pain sensation in skin, low metabolism, tunnels, long life
How extensive is their patagium? for dermoptera
neck>forepaws, forepaws>hind feet & between toes
What physical structures would be important as suckling evolved?
nipple & sealed oral cavity for suction
Do flying squirrels actually fly?
no they glide
Did all forms of pelycasaurs have sails? Where did the sails come from? What was its function?
no, from elongation of neural spines, allow them to warm up quickly & retain heat by restricting blood flow
What other mammalian taxon echolocates?
odontocetes (whales & dolphins)
Monotremes today are separated into two families. What are those two families? Where are they found. What features do they share? What are some derived features/specializations of the platypus?
ornithorryhchidae & tachyglossidae; new guinea, australia; both lack teeth as adults and have leathery bill/beak, electroreceptors around bill for food binding; platypus has more electroreceptors, sperm are bird like and shaped like thread, males have venemous spurs on legs for defense
What were the three main SYNAPSID radiations?
pelycosaurs, therapsids, mammals
How are bats crucial for the ecosystem?
pest control, pollinate plants & distribute seeds
How does the queen prevent the other mole-rats from breeding?
pheromones
Which clade of cynodonts gave rise to mammals?
probainognathia
What is a lagomorph?
rabbit
What is the primary difference between a rat and a mouse (easy answer)
rats are bigger
To which clade do naked mole-rats belong?
rodentia
Archonta includes what 3 groups of taxa?
scandentia, primates, dermoptera
Where do mammary glands come from?
sebaceous glands
Describe the various skeletal modifications as therapsids became mammals
skull fenestration, condition of the lower temporal bar (zygomatic arch bows outward for attachment of jaw muscles), specialized hterodont dentitionnnn, diphydont, bony secondary palate (breathe & eat), parietal foramen (lost), position of limbs under body, shorter toes, lighter girdle
How big were the earliest mammals? What were they probably eating?
smaller than a mouse, insects
Why do burrowing marsupials tend to have backwards facing pouches?
so dirt doesn't enter
How does echolocation work?
sound waves produce echoes when they hit the prey
Where are Xenartha primarily found?
south america
Which rodent clade are scandentia most like?
squirrels
Mammals are derived from which clade of amniotes?
synapsid
What was the thylacine? What happened to it?
tasmanian wolf, extinct
When did rodents, marsupials, primates and ungulates (hoofed mammals) appear in North America?
tertiary period
Which taxon is a morphological link to between pelycosaurs and therapsids?
tetraceratops
What taxon replaced pelycosaurs?
therapsids
What clade represented the major predators during the late Permian/early Triassic?
theriodonts
How are microchiroptera able to find areas of highest blood concentration?
thermoreceptors on the nose
When are the young ready to leave the nest for flying squirrels?
10 weeks
How many species of chiroptera are there?
1100
How many armadillo species?
19
What/when were the two major radiations of mammals?
1st: jurassic to early cretaceous- morganucodonts, docodonts, triconodonts, symmetrodonts 2nd: cenozoic, therians & multituberculates
How many sensory (Eimers organs) organs are on a star-nosed mole's nose?
25,000
When did therapsids appear in the fossil record?
267 mya
How many lineages remain of the original mammal radiation?
3
What % of mammal species are comprised of rodents?
40%
There are approximately how many species of mammals?
4500
What were the dicynodonts? Where did they get their name?
Herbivore therapsids. Double tusks, no other teeth but had beak to grind plants.
What two major groups arose during the Cenozoic? The Laurasian radiation included which clades? The Gondwanan radiation included which clades?
Laurasian and Gondwanan. Laurasian included the Multituberculates and Therians. Gondwanan included the Monotremes and Metatherians.
What are some beneficial uses for muroids?
used in medical research, trained as bomb/drug sniffers, food for predators
Describe several features specific to its aquatic lifestyle of capybara
webbed feet for swimming, nostrils, eyes on top of head,