Metatheria: Marsupial Mammals• First fossils are from Asia (Lauraisa) ~ 125 MYA.• Complex biogeography, related to the formation and rupture
of Gondwanaland
Hypothesized Single Dispersal to Australia
Metatheria: Marsupial MammalsSingle Dispersal Hypothesis
Supported by phylogenies of extant taxa:(Nilsson et. al, 2010. PLoS Biology)
Challenged by phylogenies with fossil taxa:(Beck 2012. Naturwissenschaften)
Order Didelphimorphia, Family DidelphidaeDidelphis - American opossum
Order Didelphimorphia, Family Didelphidae
Marmosa: mouse opossums
Monodelphis:short-tailed opossums
Order Paucituberculata, Family CaenolestidaeCaenolestes - shrew opossums
Order Microbiotheria, Family MicrobiotheriidaeDromiciops – Monito del monte
Australian Groups
Order Notoryctemorphia, Family NotoryctidaeNotoryctes - marsupial mole
Fossorial Adaptations Small eyes and small pinnae Fur is velvety – doesn’t lie in one direction Fusiform body with a short tail
Forelimbs modified for digging
Order Dasyuromorphia, Family Dasyuridae
Sarcophilus - Tasmanian devil
Antechinus – Marsupial mouse
Order Dasyuromorphia, Family ThylacinidaeThylacinus cynocephalus - Tasmanian wolf
Order Dasyuromorphia, Family MyrmecobiidaeMyrmecobius - numbat
Myrmecophagus adaptations:Long rostrum Long, protrusible tongueDelicate dentary Copious, sticky salivaTeeth reduced/absent Forelimbs modified for digging
Order Peramelemorphia, Family PeramelidaeMacrotis - rabbit-eared bandicoot (bilby)
Syndactylous - one sheath of skin for >1 digit (2nd & 3rd).
Order Diprotodontia
Largest order: 10 Families
Most forms have just two lower incisors.
Many forms are syndactylous.
Order Diprotodontia, Family PhalangeridaeTrichosurus vulpecula – Common brush-tailed possum
Order Diprotodontia, Family PetauridaePetaurus breviceps - sugar glider
Order Diprotodontia, Family PhascolarctidaePhascolarctus cinereus - koala
2nd & 3rd digits syndactylous
Order Diprotodontia, Family PhascolarctidaePhascolarctus cinereus - koala
- Our first example of an arboreal foliavorelow quality foodeat almost constantly while awakesleep to digestlow metabolism heterothermicdense fur to retain body heat
Order Diprotodontia, Family VombatidaeLasiorhinus - hairy-nosed wombat
Order Diprotodontia, Family MacropodidaeMacropus rufus - red kangaroo
Extreme adaptations for saltation (bipedal hopping)
Order Diprotodontia, Family MacropodidaeDendrolagus - tree kangaroo
Order Diprotodontia, Family MacropodidaePetrogale - rock wallaby
