My own Mammalogy exam 2 study guide
Chiroptera
Understand what makes Chiroptera unique among mammals and explore the vast global diversity of bats
Powered flight. Chiroptera means “hand wing”.
Sophisticated echolocation
Predominantly nocturnal
Some hibernate
Exhibit a wide range of life strategies
Provide large economic benefits to humans
Describe the basic life histories and strategies of bats We will dive deeper with eastern U.S. species
Microchiroptera | Megachiroptera |
---|---|
“Echolocating or micro bats” | “Old world fruit bats or flying foxes” |
Every continent except Antarctica | Tropical and subtropical regions of Asia, Africa, Australia, and throughout the islands of the Indian Ocean and Oceania |
Generally small size | Generally large size |
Most use echolocation and have a developed tragus | Do not echolocate and do not have developed tragus |
Predominantly insectivorous | Predominantly fruit and nectar eaters |
Majority of bats |
Bats have a number of different feeding strategies. Most types are insectivores, but they can also be:
Frugivores (fruit eating)
Carnivores (meat eating)
Sanguinivores (blood eating)
Nectarivores (Nectar eating)
Piscivores (fish eating)
Describe the morphology of bats and how that relates to their unique life strategies
Aspect ratio is wing length/width.
High aspect ratio(long narrow wings)= fast flight, lower maneuverability, generally open areas, and aerial hawking
Low aspect ratio (short, wide wings)= slow flight, higher maneuverability, generally cluttered habitat, and gleaning.
Wing loading: body mass/wing area
Describe how bats perceive their environment and locate resources
While many bats possess echolocation that allows them to “see” via hearing, those bats also have decent smell and vision. Most of these kinds of bats eat insects, meat, or fish.
Bats that do not possess echolocation have excellent vision and senses of smell, and they primarily consume fruit and nectar.
Understand modern threats facing bats and explore conservation work being done to protect bats
The biggest issue bats are facing right now is white-nose syndrome, a fungal infection that wakes up bats during hibernation too frequently, which causes them to burn through their energy too fast, essentially starving them.
Other issues:
Wind turbine collision
Pesticides
Habitat conversion and fragmentation
Human persecution
Artificial light at night
Conservation efforts:
Education/nonprofits
Habitat protection -> ESA & state protections
Cave closures
Research that informs management and conservation
Wind energy technology advancements
Large scale monitoring efforts
Citizen Science and Bat houses
Orders Monotremata and Marsupiala
Describe the major morphological differences between Prototherians (monotremes),
Metatherians (marsupials), and Eutherians (placentals)
i. Anatomy (pectoral girdle)
Monotremes have an interclavicle and resemble early synapsid pectoral girdles. Therians (marsupials and placentals) lack an interclavicle and have pectoral girdles that are very different from early synapsids.
ii. Reproduction
Monotreme females have a cloaca, 2 uteri, and large eggs. Males have 2-4 headed penises and internal testes (no scrotum)
Lay eggs,
have altricial young (helpless, dependent young),
echidnas lay eggs directly into their pouches,
platypuses keep egg in a nest or burrow
Mammae secrete directly onto skin, no nipples
Marsupial females have 3 vaginas (2 lateral vaginas and 1 medial vagina) and 2 uteri. Males have forked penises (to match the 2 lateral vaginas) and scrotums anterior to their penises.
altricial young
young climb from vaginal opening to nipple or pouch
Pouch=marsupium
Placentals:Placental females have 1 vagina and 1 uterus. Males have scrotums anterior to their penises
produce young along a gradient from altricial to precocial
long gestation periods relative to lactation period
Lactation is generally more energetically costly than gestation
Understand where extant marsupial originated and how they came to occupy only North America, South America, and Australia
Extant marsupials originated in South America and spread to North America via the Great Biotic exchange (Opposums) and to Australia by way of Antarctica.
Describe traits of orders of monotremes and marsupials
Ornithorhynchidae (platypus)
Monotypic (group that includes a single taxon): duck-billed platypus(Ornithorhynchus anatinus)
males have venomous spur (subaceous gland!): defend breeding territory, maybe predator defense
semiaquatic, semifossorial (bank burrows)
Insectivore
Electroreception in bill
Tachyglossidae (echidnas)
Two monotypic genera
short-beaked echidna (Tachyglossus aculeatus)
long-beaked echidna (Zaglossus bruijni)
insectivore, myrmecophagous
electroreception in bill
quills
Didelphimorphia (North and South America) Didelphidae (opossum)
polyprotodont (>4 upper incisors)
omnivore
opposable pollex (thumb or first digit on the forefoot), climbing
incrassated tails store fat in the base of their tail for periods of torpor
Paucituberculata (South America) Caenolestidae (shrew/rat opossum)
diprotodont (two prominent lower incisors)
insectivorous or omnivorous
Microbiotheria (South America) Microbiotheriidae
Single species- Monito del monte (little monkey of the mountains) (Dromiciops gliroides)
polyprotodont (>4 incisors)
frugivore
hibernates and engages in torpor
incrassated tails store fat in the base of their tail for hibernation/torpor
Dasyuromorphia (Australia)
Dasyuridae (17 genera and 76 species), Myrmecobiidae (1 species),Thylacinidae (Tasmainian ‘tiger’ [extinct])
carnivores & insectivores
many have incrassated tails
Peramelemorphia (Australia)
Peramelidae (Bandicoot), Thylacomyidae (bilbies [aka rabbit-eared bandicoots])
polyprotodont
omnivorous
syndactylous (second and third hind digits joined in a common skin sheath)
used for grooming
Notoryctemorphia (Australia) Notoryctidae (marsupial moles)
fossorial
insectivore
fusiform (torpedo like body)
Diprotodontia (Australia; 11 families)
Phascolarctidae (koalas), Vombatidae (wombats), Phalangeroidea (pygmy possums), Phalangeridae (bushtail possums), Pseudocheiridae (ringtail possums), Tarsipedidae (honey possum), Acrobatidae (feather-tailed gliders), Petauridae (more gliders), Potoroidae (potoroos and bettongs), Hypsiprymnodontidae (musky rat-kangaroo), Macropodidae (13 genera; wallabies, kangaroos)
highly diverse traits/adaptations
occupy many niches
Outline main points discussed in Gordon et al. 2021
Large herbivores have large impacts on the vegetation communities upon which they rely
Extirpation of large carnivores and conversion of forest/shrubland to ranchlands (grasses) and row crops across much of the Earth’s surface, which causes prey species populations to grow.
To reduce kangaroo abundance in Australia, the government enacted a cull. 70% of the population was in favor of the cull, the other 30% were very opposed. Outreach and education provided by journalists, film makers led to greater acceptance of culling policies (scientists and policy makers better understood concerns of citizens not in favor of lethal management, and citizens better understood the need for management)
Government needed to know how many kangaroos the environment could sustain without experiencing the negative impacts of herbivory.
Active management of kangaroo populations and conversations among scientists, members of the public, and government led to interest in managing for biodiversity, not only plant community and kangaroo health.
Afrotheria
Describe why taxonomists have created the Super Order Afrotheria.
Think about:
a) Historical biogeography and tectonics
Africa was isolated from ~105-~40mya
b) Phylogenetics
There are 2 main groups in Afrotheria: clade Afroinsectiphilia and clade Paenungulata. These are determined by genetics
c) Common characteristics
high vertebral counts, the relatively late eruption of the permanent dentition, and undescended testes remaining internal near the kidneys
Describe characteristics shared by each of the two clades within Afrotheria
Afroinsectiphilia:
Mostly insectivorous
some dental synapomorphies
Paenungulata:
Herbivores
hindgut fermenters
lateral molar progression (mesial drift [horizontal rather than vertical replacement]) (Proboscidea, Sirenia)
two mammae
Short nails (no big ‘claws’, no hooves)
Describe common characteristics shared among members of each order
Order Macroscelidea (sengis/elephant shrews)
proboscis (hence “elephant”)
large hind limbs
large ears
mostly insectivorous (dilambdodont), sometimes omnivorous
morphologically convergent with rodents
ecologically convergent with shrews (mostly)
socially monogamous
maintain intricate trail network
Order Afrosoricida
Insectivores
Convergent evolution
Order Tubulindentata
widely distributed south of Sahara Desert
insectivorous, largely myrmecophagous
long, sticky lounge like ant eater
peg like teeth (ant eaters lack teeth)
strong diggers, large burrow system, dig up ant/termite mounds
claws are unique nail/hoof like
cryptic
Order Proboscidea
large proboscis (‘trunk’)
large ears (radiators)
sparsely furred
fatty cushion on feet to support large body
Order Hyracoidea
Three hind toes, two with hoof-like nails
Glandular pads adapted to climbing on rocks and branches
Tree and rock species
Herbivores
Colonial
Upper incisors form tusks
Two, large cecum
Order Sirenia
100% marine/aquatic
only herbivorous marine mammal
restricted to shallow waters where plants grow
Xenarthra, Scandentia and Dermoptera
Understand characteristics shared by members of Superorder Xenarthra
Only found in the western hemisphere
Xenarthra = “strange joints”, 2 supplemental processes on each vertebra.
low metabolic rate
low body temperature(34 degrees C compared to 36-38 degrees in most mammals)
no incisors or canines
if cheek teeth, peg-like
Compare and contrast characteristics of the two orders within Xenarthra
Pilosa
Herbivorous (sloths)
Myrmecophagous (anteaters)
large, recurved claws.
Sloths have multi chambered stomach with symbiotic microbes for breaking down plant material
Anteaters lack teeth
Cingulata
Myrmecophagous (armadillos)
homodont
Be able to discuss the motivation for, and key findings of, Pauli et al. 2014
The motivation for Pauli et al. is the fact that three-toed sloths descend trees to defecate despite high mortality in doing so. It was hypothesized that there must be a benefit to the sloths that outweighs the negative of predation. Previously, it was believed that the moths that lived in the sloth’s fur had a commensal, or phoretic, relationship with the sloth (the moths benefit, and the sloths are not affected at all, negatively or positively). Analysis of the algae in the fur of three-toed sloths vs two-toed sloths, which do not descend to defecate, revealed that three-toed sloth algae had more lipids and nutrients. These benefits were brought in by the moths. Therefore, the relationship between moths, sloths, and algae is three-way commensalism.
Primates
Describe the eight characteristics shared by all primates
1. Refined hands and digits with nails replacing claws
2. Binocular stereoscopic vision
3. Postorbital bar or plate
4. For their body size, especially long lived, slow reproduction, and extended developmental time
5. Spectrum of social systems (relatively asocial to highly social)
6. Bunodont molars, large canines, incisors (mostly omnivorous)
7. Reduced rostrum and sense of smell
8. Large absolute and relative brain size (high cognitive ability)
Name and describe differences between two suborders of primates
Haplorhini:
post orbital plate
relatively short rostrum
upper incisors continuous
Strepsirhini:
post orbital bar
relatively long rostrum
gap in upper incisors
Discuss in detail the factors that threaten primate populations and species across the
globe
The biggest factor is habitat loss from deforestation. The reasons for deforestation are lumbar/paper goods, conversion to agriculture, mining, high GDP countries investing in extractive resources, and global population growth. Other factors threatening primate populations are exploitation (pet trade, food, medical research) and climate change.
Rodentia and Lagomorpha
Describe general characteristics of Rodentia and what morphological features differentiate its suborders (skull and mandible morphology)
General characteristics of rodentia
Name Rodentia is derived from the Latin rodere (to gnaw) and dentis (tooth)
Single pair of large upper and lower incisors
Large incisors are ever-growing, used for clipping and gnawing
Anterior side of incisors covered with enamel and wears more slowly than the posterior side, which lacks enamel, creating characteristic chisel-like teeth
Diastema
Suborder skull morphology
Protragomorphous- no real muscle attachment at infraorbital foramen
Hystricomorphous - Huge infraorbital foramen (nickel sized)
Sciurmorphous- large infraorbital foramen
Myomorphous- small infraorbital foramen
Mandible morphology
Sciurognathous (simple/common angular process)
Hystricognathous (strongly deflected angular process) large jaw surface area for muscle attachment; stronger bite.
What features distinguish lagomorphs from rodents?
Fenestrated maxilla, Cecal/hindgut fermenters, second set of peg like incisors
What are the two families that comprise the Lagomorpha?
Ochotonidae (pikas)
Pareitals lack fenestra
No supraorbital process
Second incisor peg-like
leporidae (rabbits and hares)
Fenestrated fenestra
Supraorbital processes
Tiny second incisor
In what ways do hares and rabbits differ?
Hares | Rabbits |
---|---|
Offspring precocial, called “leverets” | Offspring altricial, called “kits” |
postorbital process does not extend to parietal | postorbital process extends to parietal |
Triangular interparietal bone absent | Triangular interparietal bone |
Carnivora
Describe defining characteristics of Order Carnivora
Well developed canines
Carnassial pair teeth (P4, m1)(reduced in omnivores)
Well developed facial musculature
Large, c-shaped mandibular fossa
Anal scent glands (communication)
Describe key differences between suborders of Order Carnivora
Caniformes | Feliformes |
---|---|
longer rostrum, no transbullar septae | short rostrum, transbullar septae |
No caniformes have retractable claws | Most (but not all) feliformes have retractable claws |
Describe why carnivores need more space to survive than other mammals of similar size
Trophic pyramid: since carnivores eat meat and are higher up in the trophic pyramid, they need more space, since energy is reduced as it travels up the levels or the pyramid. Energy is reduced 10 times per energy level (each level gets 1/10 of the energy from the level below it), so higher levels need 10 times as much space per level to get as much energy.
This is a big issue with habitat loss and fragmentation.
Describe and define mesocarnivore release and trophic cascades
Trophic cascade: Indirect interactions between carnivores and plants mediated by direct interactions between carnivores and herbivores. There are 2 types: numerically mediated, wherein predators reduce the amount of prey, and behaviorally mediated, where predators change the behaviors of prey.
Mesocarnivore release: When a larger carnivore is removed from an area, smaller carnivores become more numerous, which leads to increased predation of small prey species and may cause declines in their population.
Describe challenges to the conservation of large carnivores
Habitat loss: since carnivores need more space than other animals of relatively similar body sizes and masses, they are more vulnerable to habitat loss and fragmentation.
Conflict with many human interests: livestock production, competition with humans for prey species like deer, they prey on pets, and are considered scary.
Felidae
With regards to taxonomy, focus on the two subfamilies
The two subfamilies, Pantherinae and Felinae, split around 10.8 million years ago. Both are monophyletic groups. Taxonomy is still not totally resolved
Describe differences between the two subfamilies
The biggest difference between the two families is the ability to roar or purr. Pantherinae (the big cats) have specially structured larynxes that allow them to roar but not purr, whereas Felinae (the small cats) have bony hyoids that let them purr but not roar.
Describe all the traits of Felidae and understand their function
All felids make these sounds: meowing, spitting, hissing, snarling, and growling.
Highly sensitive whiskers above eyes, on cheeks and muzzle, but not below the chin (navigate in dark and capture and hold prey)
Skull is foreshortened with a rounded profile and large orbits (kind of ball shaped)
Carnassials (premolar teeth specialized for shearing flesh from bone) and highly innervated canines to feel notches between vertebrae
Well developed sagittal crest where jaw muscles attach for powerful bite
Digitigrade (walk on toes). Paws on cats have glands between the toes. These interdigital glands secrete scent that cats use to mark territory
Most have retractable claws
Intervertebral discs contain extra elastic, spongy cushioning compared to those found in humans. Allows -flexible spine that can rotates opposite directions at the same time
Scapula and shoulder blades are free-floating, which allows them to fit through small spaces
Cat eyes have a tapetum lucidum, a layer of tissue in the eye lying immediately behind the retina. It reflects visible light back through the retina, increasing light available to the photoreceptors, which helps them see better in the dark
Tongue covered with 5 types of horny papillae or spines, which rasp meat from prey and aid in grooming.
Lack many taste buds, and cannot taste sweet.
Felids have a special sense receptor, vomeronasal organ (also Jacobson’s organ) in the roof of the mouth, allowing them to "taste" the air for food and pheromones. The use of this organ is associated with what is known as the Flehmen response
Cats have much shorter digestive tracts than other mammals and even other carnivores, since raw meat is more rapidly digested. Cats are obligate carnivores and cannot digest plant material.
Most cats are solitary, with the exception of lions
Orders Perissodactyla & Cetartiodactyla, Infraorder Cetacea
Describe what characteristics differentiate ungulates from other mammals
Walk on tips of their toes, which end in keratinized hoofs. (keratin is specialized skin cells)
Reduced number of toes (<5)
Heel bone (calcaneum) articulates with the astragalus rather than fibula like in other mammals (only in hind limbs)
Describe what differentiates Orders Perissodactyla and Cetartiodactyla
Perissodactyla have an odd number of toes (1,3), while cetartiodactyla have an even number of toes (2,4).
Perissodactyla also have hindgut fermentation and upper incisors, while most Cetartiodactyla have ruminant digestion (except suids) and no upper incisors (except suids)
Understand differences between three Families of Perissodactyls
Family Equidae
7-9 species
Originated and diversified in
Great Basis of North America
Modern distribution across Africa and Eurasia
Most species are threatened or endangered
Cannon bone
Evolved from browser to grazer feeding strategies
Family Tapiridae
2 genera, 4 species
Distributed across the tropics of South America and SE Asia
Inhabit dense forest, mixed feeders
Proboscis like rostrum
4 toes on front foot, 3 toes on back
all threatened or endangered
Family Rhinocerotidae
4 genera, 5 species
Name means “nose horn”
Characteristic horn(s) on rostrum, which have no bony core or keratinized sheath, simply a mass of keratinized fibers
All species threatened or endangered
Occupy tropical rainforests, floodplains, grasslands, and scrublands
Understand differences between Suborders of Cetartiodactyla
Suborder Ruminantia
All have horns or antlers
Globally distributed
Most economically important group
Suborder Suina
Two families
Pigs/hogs (Suidae) & peccaries (Tayassuidae)
Most primitive group of ungulates
Globally distributed except Antartica
Habitat generalists
Omnivorous
Monogastric digestion
Upper incisors, bunodont molars
Tusks
Large litter size
Suborder Tylopoda
Three-chambered stomach, “simple ruminants”
Distributed across South American and Eurasian deserts/arid grasslands
Soft hooves with nails (unlike other ungulates), adaptation for walking in sand, soft surfaces
Family Hippopotamidae (suborder Whippomorpha)
“River horse”, aquatic
Two genera, two species (common hippopotamus, pygmy hippotamus)
Diverged from cetaceans around 55 mya
Common hippo ~ 3,000 lb, second largest land mammal after elephants
Used to be grouped with pigs because bunodont molars
herbivorous, feed on land
hydrodefecator
large tusk-like canines
Used to be much more speciose
Describe Cetacean evolution, morphology, physiology
Cetaceans transitioned from land to sea during eocene (50 mya). Their ancestor was toothed, semi-aquatic, and foraged in shallow water, and also possessed an astragalus. As they transitioned to water animals, their nostrils moved backward and they lost their hind limbs.
Morphology:
Fusiform body type
Dense bones allow for diving
Blubber
“Telescoped” skull: posterior bones of the cranium are compressed and overlap one another to help protect the head from high pressure during dives
Physiology:
Dense bones aid diving
Rigid airways prevent collapse during dives
High oxygen efficiency:
Hematocrit (2x density of red blood cells)
Myoglobin (oxygen binding capacity in muscle cells)
Extra capillaries
Lung collapse
Be able to discuss key findings of Esmaeili et al. 2021
Similar to Jarman-Bell principle; bigger herbivores forage for plants in older phenological stages (which aren’t as high quality--provide less protein and are more fibrous) and smaller herbivores forage for earlier phenological stages (more protein).
Chiroptera
Understand what makes Chiroptera unique among mammals and explore the vast global diversity of bats
Powered flight. Chiroptera means “hand wing”.
Sophisticated echolocation
Predominantly nocturnal
Some hibernate
Exhibit a wide range of life strategies
Provide large economic benefits to humans
Describe the basic life histories and strategies of bats We will dive deeper with eastern U.S. species
Microchiroptera | Megachiroptera |
---|---|
“Echolocating or micro bats” | “Old world fruit bats or flying foxes” |
Every continent except Antarctica | Tropical and subtropical regions of Asia, Africa, Australia, and throughout the islands of the Indian Ocean and Oceania |
Generally small size | Generally large size |
Most use echolocation and have a developed tragus | Do not echolocate and do not have developed tragus |
Predominantly insectivorous | Predominantly fruit and nectar eaters |
Majority of bats |
Bats have a number of different feeding strategies. Most types are insectivores, but they can also be:
Frugivores (fruit eating)
Carnivores (meat eating)
Sanguinivores (blood eating)
Nectarivores (Nectar eating)
Piscivores (fish eating)
Describe the morphology of bats and how that relates to their unique life strategies
Aspect ratio is wing length/width.
High aspect ratio(long narrow wings)= fast flight, lower maneuverability, generally open areas, and aerial hawking
Low aspect ratio (short, wide wings)= slow flight, higher maneuverability, generally cluttered habitat, and gleaning.
Wing loading: body mass/wing area
Describe how bats perceive their environment and locate resources
While many bats possess echolocation that allows them to “see” via hearing, those bats also have decent smell and vision. Most of these kinds of bats eat insects, meat, or fish.
Bats that do not possess echolocation have excellent vision and senses of smell, and they primarily consume fruit and nectar.
Understand modern threats facing bats and explore conservation work being done to protect bats
The biggest issue bats are facing right now is white-nose syndrome, a fungal infection that wakes up bats during hibernation too frequently, which causes them to burn through their energy too fast, essentially starving them.
Other issues:
Wind turbine collision
Pesticides
Habitat conversion and fragmentation
Human persecution
Artificial light at night
Conservation efforts:
Education/nonprofits
Habitat protection -> ESA & state protections
Cave closures
Research that informs management and conservation
Wind energy technology advancements
Large scale monitoring efforts
Citizen Science and Bat houses
Orders Monotremata and Marsupiala
Describe the major morphological differences between Prototherians (monotremes),
Metatherians (marsupials), and Eutherians (placentals)
i. Anatomy (pectoral girdle)
Monotremes have an interclavicle and resemble early synapsid pectoral girdles. Therians (marsupials and placentals) lack an interclavicle and have pectoral girdles that are very different from early synapsids.
ii. Reproduction
Monotreme females have a cloaca, 2 uteri, and large eggs. Males have 2-4 headed penises and internal testes (no scrotum)
Lay eggs,
have altricial young (helpless, dependent young),
echidnas lay eggs directly into their pouches,
platypuses keep egg in a nest or burrow
Mammae secrete directly onto skin, no nipples
Marsupial females have 3 vaginas (2 lateral vaginas and 1 medial vagina) and 2 uteri. Males have forked penises (to match the 2 lateral vaginas) and scrotums anterior to their penises.
altricial young
young climb from vaginal opening to nipple or pouch
Pouch=marsupium
Placentals:Placental females have 1 vagina and 1 uterus. Males have scrotums anterior to their penises
produce young along a gradient from altricial to precocial
long gestation periods relative to lactation period
Lactation is generally more energetically costly than gestation
Understand where extant marsupial originated and how they came to occupy only North America, South America, and Australia
Extant marsupials originated in South America and spread to North America via the Great Biotic exchange (Opposums) and to Australia by way of Antarctica.
Describe traits of orders of monotremes and marsupials
Ornithorhynchidae (platypus)
Monotypic (group that includes a single taxon): duck-billed platypus(Ornithorhynchus anatinus)
males have venomous spur (subaceous gland!): defend breeding territory, maybe predator defense
semiaquatic, semifossorial (bank burrows)
Insectivore
Electroreception in bill
Tachyglossidae (echidnas)
Two monotypic genera
short-beaked echidna (Tachyglossus aculeatus)
long-beaked echidna (Zaglossus bruijni)
insectivore, myrmecophagous
electroreception in bill
quills
Didelphimorphia (North and South America) Didelphidae (opossum)
polyprotodont (>4 upper incisors)
omnivore
opposable pollex (thumb or first digit on the forefoot), climbing
incrassated tails store fat in the base of their tail for periods of torpor
Paucituberculata (South America) Caenolestidae (shrew/rat opossum)
diprotodont (two prominent lower incisors)
insectivorous or omnivorous
Microbiotheria (South America) Microbiotheriidae
Single species- Monito del monte (little monkey of the mountains) (Dromiciops gliroides)
polyprotodont (>4 incisors)
frugivore
hibernates and engages in torpor
incrassated tails store fat in the base of their tail for hibernation/torpor
Dasyuromorphia (Australia)
Dasyuridae (17 genera and 76 species), Myrmecobiidae (1 species),Thylacinidae (Tasmainian ‘tiger’ [extinct])
carnivores & insectivores
many have incrassated tails
Peramelemorphia (Australia)
Peramelidae (Bandicoot), Thylacomyidae (bilbies [aka rabbit-eared bandicoots])
polyprotodont
omnivorous
syndactylous (second and third hind digits joined in a common skin sheath)
used for grooming
Notoryctemorphia (Australia) Notoryctidae (marsupial moles)
fossorial
insectivore
fusiform (torpedo like body)
Diprotodontia (Australia; 11 families)
Phascolarctidae (koalas), Vombatidae (wombats), Phalangeroidea (pygmy possums), Phalangeridae (bushtail possums), Pseudocheiridae (ringtail possums), Tarsipedidae (honey possum), Acrobatidae (feather-tailed gliders), Petauridae (more gliders), Potoroidae (potoroos and bettongs), Hypsiprymnodontidae (musky rat-kangaroo), Macropodidae (13 genera; wallabies, kangaroos)
highly diverse traits/adaptations
occupy many niches
Outline main points discussed in Gordon et al. 2021
Large herbivores have large impacts on the vegetation communities upon which they rely
Extirpation of large carnivores and conversion of forest/shrubland to ranchlands (grasses) and row crops across much of the Earth’s surface, which causes prey species populations to grow.
To reduce kangaroo abundance in Australia, the government enacted a cull. 70% of the population was in favor of the cull, the other 30% were very opposed. Outreach and education provided by journalists, film makers led to greater acceptance of culling policies (scientists and policy makers better understood concerns of citizens not in favor of lethal management, and citizens better understood the need for management)
Government needed to know how many kangaroos the environment could sustain without experiencing the negative impacts of herbivory.
Active management of kangaroo populations and conversations among scientists, members of the public, and government led to interest in managing for biodiversity, not only plant community and kangaroo health.
Afrotheria
Describe why taxonomists have created the Super Order Afrotheria.
Think about:
a) Historical biogeography and tectonics
Africa was isolated from ~105-~40mya
b) Phylogenetics
There are 2 main groups in Afrotheria: clade Afroinsectiphilia and clade Paenungulata. These are determined by genetics
c) Common characteristics
high vertebral counts, the relatively late eruption of the permanent dentition, and undescended testes remaining internal near the kidneys
Describe characteristics shared by each of the two clades within Afrotheria
Afroinsectiphilia:
Mostly insectivorous
some dental synapomorphies
Paenungulata:
Herbivores
hindgut fermenters
lateral molar progression (mesial drift [horizontal rather than vertical replacement]) (Proboscidea, Sirenia)
two mammae
Short nails (no big ‘claws’, no hooves)
Describe common characteristics shared among members of each order
Order Macroscelidea (sengis/elephant shrews)
proboscis (hence “elephant”)
large hind limbs
large ears
mostly insectivorous (dilambdodont), sometimes omnivorous
morphologically convergent with rodents
ecologically convergent with shrews (mostly)
socially monogamous
maintain intricate trail network
Order Afrosoricida
Insectivores
Convergent evolution
Order Tubulindentata
widely distributed south of Sahara Desert
insectivorous, largely myrmecophagous
long, sticky lounge like ant eater
peg like teeth (ant eaters lack teeth)
strong diggers, large burrow system, dig up ant/termite mounds
claws are unique nail/hoof like
cryptic
Order Proboscidea
large proboscis (‘trunk’)
large ears (radiators)
sparsely furred
fatty cushion on feet to support large body
Order Hyracoidea
Three hind toes, two with hoof-like nails
Glandular pads adapted to climbing on rocks and branches
Tree and rock species
Herbivores
Colonial
Upper incisors form tusks
Two, large cecum
Order Sirenia
100% marine/aquatic
only herbivorous marine mammal
restricted to shallow waters where plants grow
Xenarthra, Scandentia and Dermoptera
Understand characteristics shared by members of Superorder Xenarthra
Only found in the western hemisphere
Xenarthra = “strange joints”, 2 supplemental processes on each vertebra.
low metabolic rate
low body temperature(34 degrees C compared to 36-38 degrees in most mammals)
no incisors or canines
if cheek teeth, peg-like
Compare and contrast characteristics of the two orders within Xenarthra
Pilosa
Herbivorous (sloths)
Myrmecophagous (anteaters)
large, recurved claws.
Sloths have multi chambered stomach with symbiotic microbes for breaking down plant material
Anteaters lack teeth
Cingulata
Myrmecophagous (armadillos)
homodont
Be able to discuss the motivation for, and key findings of, Pauli et al. 2014
The motivation for Pauli et al. is the fact that three-toed sloths descend trees to defecate despite high mortality in doing so. It was hypothesized that there must be a benefit to the sloths that outweighs the negative of predation. Previously, it was believed that the moths that lived in the sloth’s fur had a commensal, or phoretic, relationship with the sloth (the moths benefit, and the sloths are not affected at all, negatively or positively). Analysis of the algae in the fur of three-toed sloths vs two-toed sloths, which do not descend to defecate, revealed that three-toed sloth algae had more lipids and nutrients. These benefits were brought in by the moths. Therefore, the relationship between moths, sloths, and algae is three-way commensalism.
Primates
Describe the eight characteristics shared by all primates
1. Refined hands and digits with nails replacing claws
2. Binocular stereoscopic vision
3. Postorbital bar or plate
4. For their body size, especially long lived, slow reproduction, and extended developmental time
5. Spectrum of social systems (relatively asocial to highly social)
6. Bunodont molars, large canines, incisors (mostly omnivorous)
7. Reduced rostrum and sense of smell
8. Large absolute and relative brain size (high cognitive ability)
Name and describe differences between two suborders of primates
Haplorhini:
post orbital plate
relatively short rostrum
upper incisors continuous
Strepsirhini:
post orbital bar
relatively long rostrum
gap in upper incisors
Discuss in detail the factors that threaten primate populations and species across the
globe
The biggest factor is habitat loss from deforestation. The reasons for deforestation are lumbar/paper goods, conversion to agriculture, mining, high GDP countries investing in extractive resources, and global population growth. Other factors threatening primate populations are exploitation (pet trade, food, medical research) and climate change.
Rodentia and Lagomorpha
Describe general characteristics of Rodentia and what morphological features differentiate its suborders (skull and mandible morphology)
General characteristics of rodentia
Name Rodentia is derived from the Latin rodere (to gnaw) and dentis (tooth)
Single pair of large upper and lower incisors
Large incisors are ever-growing, used for clipping and gnawing
Anterior side of incisors covered with enamel and wears more slowly than the posterior side, which lacks enamel, creating characteristic chisel-like teeth
Diastema
Suborder skull morphology
Protragomorphous- no real muscle attachment at infraorbital foramen
Hystricomorphous - Huge infraorbital foramen (nickel sized)
Sciurmorphous- large infraorbital foramen
Myomorphous- small infraorbital foramen
Mandible morphology
Sciurognathous (simple/common angular process)
Hystricognathous (strongly deflected angular process) large jaw surface area for muscle attachment; stronger bite.
What features distinguish lagomorphs from rodents?
Fenestrated maxilla, Cecal/hindgut fermenters, second set of peg like incisors
What are the two families that comprise the Lagomorpha?
Ochotonidae (pikas)
Pareitals lack fenestra
No supraorbital process
Second incisor peg-like
leporidae (rabbits and hares)
Fenestrated fenestra
Supraorbital processes
Tiny second incisor
In what ways do hares and rabbits differ?
Hares | Rabbits |
---|---|
Offspring precocial, called “leverets” | Offspring altricial, called “kits” |
postorbital process does not extend to parietal | postorbital process extends to parietal |
Triangular interparietal bone absent | Triangular interparietal bone |
Carnivora
Describe defining characteristics of Order Carnivora
Well developed canines
Carnassial pair teeth (P4, m1)(reduced in omnivores)
Well developed facial musculature
Large, c-shaped mandibular fossa
Anal scent glands (communication)
Describe key differences between suborders of Order Carnivora
Caniformes | Feliformes |
---|---|
longer rostrum, no transbullar septae | short rostrum, transbullar septae |
No caniformes have retractable claws | Most (but not all) feliformes have retractable claws |
Describe why carnivores need more space to survive than other mammals of similar size
Trophic pyramid: since carnivores eat meat and are higher up in the trophic pyramid, they need more space, since energy is reduced as it travels up the levels or the pyramid. Energy is reduced 10 times per energy level (each level gets 1/10 of the energy from the level below it), so higher levels need 10 times as much space per level to get as much energy.
This is a big issue with habitat loss and fragmentation.
Describe and define mesocarnivore release and trophic cascades
Trophic cascade: Indirect interactions between carnivores and plants mediated by direct interactions between carnivores and herbivores. There are 2 types: numerically mediated, wherein predators reduce the amount of prey, and behaviorally mediated, where predators change the behaviors of prey.
Mesocarnivore release: When a larger carnivore is removed from an area, smaller carnivores become more numerous, which leads to increased predation of small prey species and may cause declines in their population.
Describe challenges to the conservation of large carnivores
Habitat loss: since carnivores need more space than other animals of relatively similar body sizes and masses, they are more vulnerable to habitat loss and fragmentation.
Conflict with many human interests: livestock production, competition with humans for prey species like deer, they prey on pets, and are considered scary.
Felidae
With regards to taxonomy, focus on the two subfamilies
The two subfamilies, Pantherinae and Felinae, split around 10.8 million years ago. Both are monophyletic groups. Taxonomy is still not totally resolved
Describe differences between the two subfamilies
The biggest difference between the two families is the ability to roar or purr. Pantherinae (the big cats) have specially structured larynxes that allow them to roar but not purr, whereas Felinae (the small cats) have bony hyoids that let them purr but not roar.
Describe all the traits of Felidae and understand their function
All felids make these sounds: meowing, spitting, hissing, snarling, and growling.
Highly sensitive whiskers above eyes, on cheeks and muzzle, but not below the chin (navigate in dark and capture and hold prey)
Skull is foreshortened with a rounded profile and large orbits (kind of ball shaped)
Carnassials (premolar teeth specialized for shearing flesh from bone) and highly innervated canines to feel notches between vertebrae
Well developed sagittal crest where jaw muscles attach for powerful bite
Digitigrade (walk on toes). Paws on cats have glands between the toes. These interdigital glands secrete scent that cats use to mark territory
Most have retractable claws
Intervertebral discs contain extra elastic, spongy cushioning compared to those found in humans. Allows -flexible spine that can rotates opposite directions at the same time
Scapula and shoulder blades are free-floating, which allows them to fit through small spaces
Cat eyes have a tapetum lucidum, a layer of tissue in the eye lying immediately behind the retina. It reflects visible light back through the retina, increasing light available to the photoreceptors, which helps them see better in the dark
Tongue covered with 5 types of horny papillae or spines, which rasp meat from prey and aid in grooming.
Lack many taste buds, and cannot taste sweet.
Felids have a special sense receptor, vomeronasal organ (also Jacobson’s organ) in the roof of the mouth, allowing them to "taste" the air for food and pheromones. The use of this organ is associated with what is known as the Flehmen response
Cats have much shorter digestive tracts than other mammals and even other carnivores, since raw meat is more rapidly digested. Cats are obligate carnivores and cannot digest plant material.
Most cats are solitary, with the exception of lions
Orders Perissodactyla & Cetartiodactyla, Infraorder Cetacea
Describe what characteristics differentiate ungulates from other mammals
Walk on tips of their toes, which end in keratinized hoofs. (keratin is specialized skin cells)
Reduced number of toes (<5)
Heel bone (calcaneum) articulates with the astragalus rather than fibula like in other mammals (only in hind limbs)
Describe what differentiates Orders Perissodactyla and Cetartiodactyla
Perissodactyla have an odd number of toes (1,3), while cetartiodactyla have an even number of toes (2,4).
Perissodactyla also have hindgut fermentation and upper incisors, while most Cetartiodactyla have ruminant digestion (except suids) and no upper incisors (except suids)
Understand differences between three Families of Perissodactyls
Family Equidae
7-9 species
Originated and diversified in
Great Basis of North America
Modern distribution across Africa and Eurasia
Most species are threatened or endangered
Cannon bone
Evolved from browser to grazer feeding strategies
Family Tapiridae
2 genera, 4 species
Distributed across the tropics of South America and SE Asia
Inhabit dense forest, mixed feeders
Proboscis like rostrum
4 toes on front foot, 3 toes on back
all threatened or endangered
Family Rhinocerotidae
4 genera, 5 species
Name means “nose horn”
Characteristic horn(s) on rostrum, which have no bony core or keratinized sheath, simply a mass of keratinized fibers
All species threatened or endangered
Occupy tropical rainforests, floodplains, grasslands, and scrublands
Understand differences between Suborders of Cetartiodactyla
Suborder Ruminantia
All have horns or antlers
Globally distributed
Most economically important group
Suborder Suina
Two families
Pigs/hogs (Suidae) & peccaries (Tayassuidae)
Most primitive group of ungulates
Globally distributed except Antartica
Habitat generalists
Omnivorous
Monogastric digestion
Upper incisors, bunodont molars
Tusks
Large litter size
Suborder Tylopoda
Three-chambered stomach, “simple ruminants”
Distributed across South American and Eurasian deserts/arid grasslands
Soft hooves with nails (unlike other ungulates), adaptation for walking in sand, soft surfaces
Family Hippopotamidae (suborder Whippomorpha)
“River horse”, aquatic
Two genera, two species (common hippopotamus, pygmy hippotamus)
Diverged from cetaceans around 55 mya
Common hippo ~ 3,000 lb, second largest land mammal after elephants
Used to be grouped with pigs because bunodont molars
herbivorous, feed on land
hydrodefecator
large tusk-like canines
Used to be much more speciose
Describe Cetacean evolution, morphology, physiology
Cetaceans transitioned from land to sea during eocene (50 mya). Their ancestor was toothed, semi-aquatic, and foraged in shallow water, and also possessed an astragalus. As they transitioned to water animals, their nostrils moved backward and they lost their hind limbs.
Morphology:
Fusiform body type
Dense bones allow for diving
Blubber
“Telescoped” skull: posterior bones of the cranium are compressed and overlap one another to help protect the head from high pressure during dives
Physiology:
Dense bones aid diving
Rigid airways prevent collapse during dives
High oxygen efficiency:
Hematocrit (2x density of red blood cells)
Myoglobin (oxygen binding capacity in muscle cells)
Extra capillaries
Lung collapse
Be able to discuss key findings of Esmaeili et al. 2021
Similar to Jarman-Bell principle; bigger herbivores forage for plants in older phenological stages (which aren’t as high quality--provide less protein and are more fibrous) and smaller herbivores forage for earlier phenological stages (more protein).