Marsupials

Marsupial Subclass

Theria

Marsupial Class

Mammalia

Marsupial Infraclass

metatherians/Marsupialia

What does Marsupium mean?

A purse or pouch

Whats so special about the history of Marsupials

They are the most ancestrial group and were more abundant in the last days of the dinosaurs

Define plesiomorphic

“Ancient/basal traits” early ancestral traits shared by later descendent species

What Metatheria traits have compared to Eutheria

-Choriovitelline placenta

-Gestration short and young often altricial (helpless)

-Marsupium in around 50%

-Small brain/case; lacks corpus callosum; simple neocortex

-Weak patella

-Epipubic bones

-Angular process inflected perpendicular to dentary

Large vacuities in posterior palate

Possums Order and Family

Order: Didelphimorphia

Family: Didelphidae

Moniito del monte Order and Familyh

Microbitotheria

Dasyurids(Tasmanian Devil) Order and Family

Order: Dasyuromorphia

Family: Dasyuridae

Tasmanian tiger/wolf order and family

Order: Dasyuromorphia

Family: Thylacinidae

Wombat Order and Family

Order: Diprotodontia

Family: Vombatidae

Koala family and order

Order: Diprotodontia

Family: Phascorlarctidae

Marsupial skulls compared to Eutherians

-Smaller braincase:cranum ratio

-“Higher” Cheekbones extend more rearward

-Auditory Bullae not present

-Foramen lacrimale

-Jugal bone larger

-Angular process inflects medially to axis of dentary

-Palatal vaculities (holes) more frequent that eutherians (back of upper mouth)

-Primitive Dental formula, # upper incisors usually > lower

-5/1/3/4 maruspals vs 3/1/4/3 eutherian

-Only 3rd permolar has a deciduous predecessor

Plyprotodont

Lower and upper extend - the same length and lower jaw teeth laregly unspecialized

Diprotodont

lower jaw is shortened, and pair of lower incisors are lengthend to meet jaw

Didactylous

unfused digits

Syndactylous

2nd and 3rd toes share skin and are fused together = “Syn”

Bifurcated repro tract

2 Lateral vagina where sperm migrate a 3rd medial that is the birth canal and 2 uteri

Pseudovagina

Marsupial birth canal

Marsupial gestration and lactation periods compared to eutherians

Marsupials have short gestation period and longer lactation period caompared to eutherains

Do Marsupials have a placentas?

Yes they do just nearly always more weakly attached

Why type of placenta does marsupials have compared to Eutherians

Marsupials have a Choriovitelline placenta which form from union of yolk sac and chorion

Eutherians have a Chrorioallantoic placenta which forms from union of chorion and allantois

Virginia opossum Latin, Family, Order

Latin: Didelphis virginiana

Family: Dedelphidae

Order: Didelphimorphia

Didelphis plesiomorphic characteristics

-Tribosphenic cheek teeth base

-Pentadactyl: have five digits per leg (Opposable pollex)

Define Prehensile tail

Long and sparsely haired, tail assist in their semi-arboreal habits

Define Incrassated tail

Storing fat in the base of their tail

Which family is Semelparity

Dasyuridae (Mice/Shrews)

Tasmanian Devil Latin, Family, Order

Latin: Sarcophilus harrissii

Family: Dedelphidae

Order: Didelphimorphia

Crepuscular

(sunup/sundown) hunting and other activity (Tasmanian Devil)

Tasmanian Wolf/Tiger Latin/Family/Order

Latin: Thylacinus cynocephalus

Family: Dedelphidae

Order: Didelphimorphia

Tasmanian Devil Facial Tumor Disease

Clonally transferable cancer, malignant type that slowly erodes facial tissues, nearly 100% mortality rate

Bandicoots family

Peramelidae

Quolls family

Dasyuridae

Marsupial Mice/Shrews family

Dasyuridae

Wombats family and order

Family: Vombatidae

Order: Diprotodontia

Koala Latin, Order and Family

Order: Diprotodontia

Family: Phascolarctidae

Latin: Phascolarctos cinereus

Schizodactylous

(2 opposing 3 digits) koala forefeet

Kangaroos Family and Order

Family: Macropodidae

Order: Diprotodontia

Define Diapause

Can be carrying embryo while nursing another

Massive Kangaroo

Procoptodon (Giant Shortfaced kangaroo)

Extinct Neotropical carnivorous marsupials

Sparassodonts

Epipubic Bones