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Flashcards in Lab Quiz 2 Deck (50):


- Reptilian features inc. sprawled limbs and egg-laying
- Teeth absent in all adults; may form tooth buds in juvenile platypuses but these disappear soon after birth
- Instead, platypuses have horny plates that are continually growing
- Lacrimal and frontal bones absent
- Jugals reduced or absent, but zygomatic processes of maxilla and squamosal meet to form complete zygomatic arch
- Jaws covered with rubbery, hairless skin
- Large claws on each digit
- Large, hollow spur on the ankle of males (and some female echidnas); venom-secreting gland at base in platypuses
- No nipples on the mammary glands
- Penis bifurcates at the tip and is attached to the ventral wall of the cloaca
- Females have 10 X chromosomes, males have 5 X & 5 Y
- Auditory bullae are absent
- Prominent epipubic bones


Epipubic Bones

Paired bones that project anteriorly from the pelvic girdle into the abdominal body


Identification of Echidnas

Skulls may resemble those of small anteaters or pangolins (which are also toothless and cone shaped)

- Echidnas have a more elevated braincase
- Premaxillae of Tachyglossus are bents lightly upward
- Anteaters have well-developed lacrimal bones (absent in echidnas and pangolins)
- Pangolin skulls tend to be more robust and lack an angular process



Infraclass, contains Superorders:
- Ameridelphia
- Australidelphia
(Total of 7 Orders)

- Marsupium in 2/3 of living species
- Always more upper than lower incisors (except wombats, Vombatidae - Diprodontia)
- Primitive formula is 3 premolars and 4 molars (reverse of placentals)
- Total number of teeth often exceeds 44
- Diprotodont teeth in two orders
- Canines and first premolars frequently incisiform
- Angular process inflected (projects medially)
- Jugal contributes to mandibular fossa in all marsupials except genus Tarsipes
- Most are plantigrade, some digitigrade
- Hallux lacks a claw in all marsupials
- Simple yolk sac placenta in most, chorioallantoic in Peramelemorphia
- Epipubic bones present in males and females, vestigeal in marsupial moles and Tasmanian wolf
- Two separate uteri with two vaginal canals (temp. median birth canal during childbirth)
- Penis often bifurcate, no baculum; scrotum anterior to penis
- Separate urogenital and digestive openings in most species (exception is Microbiotheria)



Condition where the lower jaw is shortened and the first pair of lower incisors are very enlarged and elongated



Non-diprotodont, or normal tooth condition



Condition where two toes are fused so the skeletal elements of both are encased within one skin sheath
- Two claws will project from the end of this digit



Condition with no fused digits, opposite of syndactylous



Superorder within Metatheria, contains:
- Didelphimorphia
- Paucituberculata

Marsupials from the New World



Superorder within Metatheria, contains:
- Dasyuromorphia
- Notoryctrmorphia
- Peramelemorphia
- Diprotodontia
- Microbiotheria



Order within Ameridelphia
Neotropical region, except Didelphis virginiana, which ranges into the Nearctis

- Most probably omnivorous
- Terrestrial and arboreal, one semiaquatic, some semifossorial
- Marsupium more absent than present


Identification of Didelphimorphia

- Incisors are 5/4, small, peg-like
- Polyprotodont
- Canines are well-developed
- Pentadactyl and no syndactylous digits
- Well developed hallux is clawless and more or less opposable
- Tail prehensile to semi-prehensile
- Frequently have a naked, rat-like tail

May be confused with Microbiotheria or Peramelemorphia (both have five upper incisors)
- Microbiotheria has inflated auditory bullae
- Peramelemorphia has three lower incisors


Didelphis virginiana

- Long-haired, scruffy; naked nose and ears
- Rat-like tail is furred at base, then black and naked, then has long white tip
- Five toes on each foot, opposable hallux
- Incisors 5/4

Similar species
- Norway rat is much smaller and has shorter fur, with no fur on base of tail

- Nocturnal, though sometimes active by day in winter
- Climbs well, uses prehensile tail for balance
- May "play dead" if provoked
- Omnivorous and will eat almost anything
- Solitary
- Seminomadic; dens in hollow logs, rocks, burrows made by other animals
- Female gives birth to 8-16 2g young that attach to one of 13 nipples for 2 months; 3rd month on mom's back
- May have 2-3 litters per year

- Oldfields, forests, agricultural areas, roadsides, suburbs, and urban regions

- Common to abundant
- Frequently roadkill
- Sometimes killed for meat in southern US

- Native from Central America all the way to Southern Ontario
- Introduced widely along the west coast



Order within Ameridelphia
Caenolestids - flaplips/shrew-opossums
Neotropical region

- Small and shrew-like
- Feed on invertebrates, plants, fungi and seeds


Identification of Paucituberculata

- Diprotodont
- Incisors usually 4/3
- External membranous flap on both sides of the upper and lower lips
- Marsupium always absent
- Tail long and haired to tip
- Limbs subequal
- Didactylous
- Can be distinguished from Diprodontia because they have 4 upper incisors
- Can be distinguished from mice and shrews due to clawless hallux and flaps on lips



Order within Australidelphia
Carnivorous/insectivorous marsupials - Tasmanian wolf, Tasmanian devil, numbat
Australian region

- Mostly terrestrial, a few arboreal/semifossorial


Identification of Dasyuromorphia

- Polyprotodont
- Incisors 4/3
- Canines well-developed in most
- Didactylous toes
- Hallux clawless if present
- Marsupium, if present, opens to the rear
- Non-prehensile tail
- Can be distinguished from similar eutherians because of 4 upper incisors, inflected angular process, and clawless hallux



Order within Australidelphia
Marsupial moles
Australian region

- Fully fossorial
- Live in sandy deserts
- Feed on insects


Identification of Notoryctemorphia

- Dental formula I 3-4/3 : C 1/1 : P 2/2-3 : M 4/4 (T: 40-44)
- Skull conical in shape
- Skin has horny rostral shield
- Claws are very enlarged on third and fourth digits to form spades
- Pinnae and externally visible eyes absent
- Fur silky, pale, iridescent
- Tail short, naked, conical
- Marsupium present
- Vestigial epipubic bones
- Inflected angular process distinguished from eutherians
- Skin unique in having less than 5 digits on forefeet and horny rostral shield (golden moles have small rostral pad but no external tail)



Order within Australidelphia
Bandicoots and bilbies
Australian region

- Terrestrial
- Primarily insectivorous
- Vaguely similar to rabbits in size and appearance


Identification of Peramelemorphia

- Polyprotodont
- Dental formula I 4-5/3 : C 1/1 : P 3/3 : M 4/4 (T: 46-48)
- Incisors have flattened crowns
- Wide space between canines and last incisor/first premolar
- Syndactylous digits on hind feet
- Elongate rostrum
- Skull conical in shape
- Hindlimbs larger than forelimbs
- Reduced number of digits on pes and manus
- Clavicle rudimentary or absent
- Marsupium always present, opens to rear
- Chorioallantoic placenta, but lacks villi seen in eutherians
- Can be distinguished from eutherians by number of upper incisors and inflected angular process
- Skin can be distinguished from others because of syndactylous digits



Order within Australidelphia
Kangaroos, wallabies, koalas, possums, wombats, etc.
Australian region

- Vary considerably in size
- Occupy diverse habitats
- Terrestrial, semifossorial, or arboreal


Identification of Diprotodontia

- Diprotodont
- Incisors can be 3/2-3; 3/1; 2/1 or 1/1
- Second and third lower incisors minute when present
- Syndactylous second and third digits of hind foot
- Marsupium always present, opens anteriorly or posteriorly
- Can be distinguished from paucituberculatans (who are also diprotodont) by having less than four upper incisors
- Inflected angular process means marsupials



Order within Australidelphia
Monito del monte (only extant species)
Neotropical region

- Opossum-like in appearance
- Scansorial or semiarboreal
- Lives in dense, humid forest
- Insectivorous or faunivorous


Identification of Micriobiotheria

- Polyprotodont
- Incisors 5/4
- Large, inflated auditory bullae
- Didactylous toes
- Opposable hallux
- Marsupium present
- Tail prehensile, equal in length to body, furred all over except ventral strip
- Can be distinguished from opossum skulls due to large auditory bullae
- Can be distinguished from opossum skins due to long furred tail; naked strip distinguishes from small eutherians
- Can be distinguished from diprotodontians due to didactylous digits
- Can be distinguished from rodents because of opossable hallux with no claw



Superorder within Eutheria, contains Orders:
- Cingulata
- Pilosa
Sloths, armadillos, anteaters
Neotropical region except one species ranging into southcentral Nearctic

- Extra (xenarthrous) articular surface between vertebrae, esp. in lumbar region
- Incisors are generally reduced or absent
- Deciduous teeth are absent
- Cheek teeth (when present) lack enamel
- Cheek teeth (when present) have only single, open root
- Limbs specialized for digging or climbing



Order within Xenarthra
Neotropical region and one species in Nearctic

- Terrestrial to fossorial
- Possess a carapace over much of the body, formed by plates of dermal bone that are covered in small, overlapping keratinous scutes
- Armour ranges in protection from full coverage when rolled into a ball to a thin stretch
- Most are only sparsely haired, but some are very hairy
- Most feed exclusively or primarily on insects


Identification of Cingulata

- Cheek teeth are cylindrical, homodont, and ever-growing
- No incisors or canines
- Deciduous teeth only in genus Dasypus
- Some species have more than 7 cheek teeth



Order within Xenarthra, contains Suborders:
- Vermilingua
- Phyllophaga
Anteaters and Sloths
Neotropical region



Suborder within Pilosa
Anteaters and tamanduas
Neotropical region

- Feed primarily on ants and termites
- Terrestrial and arboreal
- Tamanduas and pygmy/two-toed anteaters have prehensile tails


Identification of Vermilingua

- Edentulate
- Long slender rostrum with small mouth opening
- Long, thin, cylindrical tongue
- Large foreclaws used to tear open and and termite nests
- Can be distinguished from echidnas because they have a less elevated braincase and premaxillae are never bent upward
- Have lacrimal bones, which are in neither echidnas or pangolins



No teeth



Suborder within Pilosa
Neotropical region

- Arboreal
- Long limbs and syndactylous toes
- Large, curved claws for hanging from tree branches
- Have coarse hair that houses algae
- Vegetarian


Identification of Phyllophaga

- Incisors and canines absent
- Cheek teeth cylindrical, ever-growing and basically homodont
- Rudimentary tail
- Can have cervical vertebrae numbering more or less than 7
- Two-toed sloths have two claws on forefeet and three on hindfeet; caniniform anterior tooth
- Three-toed sloths have three claws on all four feet; all teeth essentially homodont



Superorder within Eutheria, contains Orders:
- Afrosoricida
- Macroscelidea
- Tubulidentata
- Proboscidea
- Sirenia
- Hyracoidea
Includes elephants, sirenians, hyraxes, golden moles, aardvarks, etc.
Ethiopian region

No morphological support but molecular data strongly supports this as a clade



Order within Afrotheria, contains Suborders:
- Tenrecomorpha
- Chrysochloridea
Tenrecs, otter shrews, golden moles
Ethiopian region



Suborder within Afrosoricida
Tenrecs and otter shrews
Ethiopian region

- Insectivorous
- Vary greatly in form and habits
- Shrew- to rabbit-sized
- Can resemble shrews, moles, desmans, or hedgehogs
- Otter shrews are semiquatic


Identification of Tenrecomorpha

- First upper premolar is never present
- Molars are 3/3; 4/3, or 2/2
- Upper molars have crowns that are triangular in occlusal view
- Rostrum frequently long and slender
- No auditory bullae or zygomatic arches
- No jugal
- Eyes usually small
- Obvious pinnae
- Can be distinguished from shrews because first upper incisor does not protrude, has no accessory cusp, and is never pigmented



Suborder within Afrosoricida
Golden moles
Ethiopian region

- Diet is mainly invertebrates (termites)
- Live in forests, savannahs and sand dunes
- Closely resemble true moles with the fossorial adaptations of marsupial moles


Identification of Chrysochloridea

- Dental formula I 3/3 : C 1/1 : P 3/3 : M 3/3 (T: 40)
- First upper incisor is enlarged
- Crests between cusps of upper molars are V-shaped in occlusal view
- Conical or wedge-shaped skull
- Leathery pad at tip of snout
- Auditory bullae present
- No jugal bone, zygomatic arch made by elongate processes
- Eyes are vestigial and covered in skin and fur
- Can be distinguished from true moles by V-shaped crests between cusps, weak zygomatic arch and four digits on forefeet



Order within Afrotheria
Elephant shrews/sengis
Ethiopian and Palearctic regions

- Diurnal insectivores
- Long, slender and highly mobile snout
- Snout has many basal vibrissae
- Large eyes and ears
- Hind limbs slender and elongated
- When alarmed, hop on digitigrade hind feet
- Soft fur
- Long slender tail covered with scales


Identification of Macroscelidea

- Hind limbs much longer than forelimbs
- Distal portions of limbs longer than proximal portions
- Fused tibia and fibula
- Dental formula I 1-3/3 : C 1/1 : P 4/4 : M 2/2-3 (T: 36-42)
- Fourth premolar is molariform
- Molars are usually four-cusped
- Upper molars with crests between cusps are V-shaped
- Large perforations in palate
- Complete zygomatic arch
- No complete postorbital bar
- Well-developed auditory bullae
- Can be distinguished from marsupials due to lack of inflected angular process
- Can be distinguished from Scandentia and Primates due to lack of postorbital bar
- Can be distinguished from Chiroptera and Carnivora due to poorly developed canines



Order within Afrotheria
Aardvark - Orycteropus afer
Ethiopian region

- Semifossorial
- Somewhat pig-like in appearance
- Digits terminate in structures intermediate between claws and hooves - used to burrow and tear open termite mounds
- Long, extensible tongue


Identification of Tubulidentata

- Skull is elongated and conical
- Incisors and canines are absent
- Cheek teeth usually number 5/5
- Cheek teeth are ever-growing, oval/B-shaped, flat-topped, and clumnar
- Cheek teeth lack enamel and are composed of hexagonal prisms of dentine surrounding tubular pulp cavities
- Limbs are digitigrade
- Four digits on manus and five digits on pes
- Snout is elongated and pig-like
- Ears are much longer than wide
- Tail is long and tapers gradually
- Thick skin with sparse bristle-like hairs



Order within Afrotheria
Ethiopian and Oriental regions

- Long, prehensile trunk
- Browsing and herbivorous


Identification of Proboscidea

- Incisors are 1/0 and are long, ever-growing tusks of solid dentine; frequently absent in female Asiatic elephants
- Canines absent
- Cheek teeth are hypsodont and lophodont
- Cheek teeth are replaced from the back of the jaw as worn teeth are shed from the front of each tooth row
- Limbs are graviportal and have five digits terminating in a hoof-like structure
- Upper lip and nose are fused to form the trunk, with nostrils at distal end
- Skin is thick and covered in spare, bristle-like hairs



Order within Afrotheria
Manatees and dugongs
Nearctic, Neotropical, Oriental, Australian and Ethiopian regions

- Fully aquatic
- Lack external hindlimbs
- Forelimbs modified to become flippers
- Short but flexible neck
- Mammae are pectoral
- Feed on aquatic vegetation
- Hunted for meat, hides and oil
- Tropical and subtropical


Identification of Sirenia

- External nares high on the skull, posterior to anterior margins of the orbits
- Nasal bones rudimentary or absent
- Incisors absent in manatee, 1/0 in dugong
- Canines absent
- Cheek teeth are either replaced by more teeth as in elephants or replaced by horny plates
- Vestigial pelvic limbs, not visible externally
- Pectoral limbs paddle-like, five digits indistinguishable externally
- Tail has horizontally flattened fin (cleft in dugongs)
- Manatees have only six cervical vertebrae
- Ribs are massive
- Horizontal stability enhanced by elongated lungs and horizontal diaphragm
- Eyes are small
- Pinnae absent
- Lips large and highly mobile
- Stiff vibrissae present on upper lip, otherwise body is nearly naked



Order within Afrotheria
Ethiopian region mostly, one genus in Palearctic

- Rabbit-sized, look much like rodents
- Herbivorous
- Unique foot structure grants them a firm grip on rocks and trees in which they live
- Terrestrial species live in colonies


Indentification of Hyracoidea

- Adult dental formula I 1/2 : C 0/0 : P4/4 : M 3/3 (T: 34)
- Long, rootless upper incisors are triangular in cross-section and pointed
- Lower incisors are chisel-shaped and usually tricuspid
- Cheek teeth somewhat lophodont
- Wide diastema between anterior and cheek teeth
- Well-developed postorbital process usually forms postorbital bar
- Well-developed interparietal
- Large jugals contribute to mandibular fossa
- Plantigrade
- All four digits on manus are syndactylous except for the terminal phalanges
- Pes has three digits
- Flat, hoof-like nails except for second pedal digit, with grooming nail (claw-like)
- Soles of feet have soft, elestic pads kept moist by numerous glands
- Very short tail
- Can be distinguished from rodents by tringular cross section of upper incisors and presence of two lower incisors