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So, What Are Ya, Marsupial or Placental?
Since the discovery of Deltatheridium, scientists knew that it was an early mammal. However, before the late 1990s, they debated about what kind of mammal it was. Was it a marsupial (pouched mammal such as opossums and kangaroos) or a placental (a mammal that gives birth to fully developed young, such as rats, bats, and whales)? Now, thanks to some amazing fossil evidence from the Gobi, scientists have the answer. On the mammal family tree, Deltatheridium is definitely a marsupial. Although Deltatheridium's descendants went extinct, some of its "cousins" became the marsupials we know today.
Deltatheridium prerituberculare
(del-tah-ther-ID-ee-um)
Locality Found: Mongolia
Age: Cretaceous 80 MYA
Size: 6 inches long
Prepared For: 2000 Museum exhibit Fighting Dinosaurs
Characteristics: Paleontologists believe that Deltatheridium was an early ancestor to modern day marsupials.
Deltatheridium is probably a relative to which modern animal?
kangaroo
pig
parakeet
Correct!
Scientists believe that Deltatheridium had characteristics that are very similar to marsupials (pouched animals) that live today.
Many more mammal species have lived and gone extinct than are alive today.
Fact
OR
Fiction
?
Fact
Mammals in the world today make up only a tiny part of all of the mammal species that have ever existed.
Although many kinds of mammals lived in North America during the Cretaceous, most of their fossils were destroyed.
Fact
OR
Fiction
?
Fact
Early mammal fossils from North America are no more than teeth and partial jaws. But in the Gobi, entire mammal skeletons are commonly found.
“
We found Deltatheridium—this beautiful, little skull—at our favorite site, Ukhaa Tolgod.
„
Mike Novacek, paleontologist