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25 Cards in this Set

  • Front
  • Back
Where did mammals originate from and was this mono or polyphyletic?
Monophyletically from Cynodont Synapsids
What were the 2 groups of animals that are considered a sister group of mammals and are extremely close to being mammalian?
1. Sinoconodon (Early Jurassic of Asia)
2. Adelobasileus (Late Triassic of N.Am., known only fm a braincase
Mammaliaformes are considered mammals; what is the Mammaliaforme Order called?
1. Order Morganucodontidae
When was Order Morganucodontidae (Mammaliaformes) present and where?
Late Triassic or Early Jurassic of Europe
What is the earliest known mammal (Order)?
Order Morganucodontidae
When was the Order Multituberculata (Infraclass Allotheris-Subclass Theriformes) present?
1. Existed 100 million yrs fm late Jurassic well into Eocene
2. By late Cretaceous & Paleocene, was widespread in Old & New Worlds (Holoarctic diestribution)
What are the characteristics of Order Morganucodontidae?
When did the Multituberculata disappear?
In Eocene; probably due to rapid development of rodents after already suffering competition from the Condylarths and primates
What were the advanced characteristics of the Multituberculata?
1.Molars w/parallel rows of cusps (grinding)
2.Lower premolar-specialized blade like tooth
3. Jaw rodent-like:
-Molars highly
What were the primitive characteristics of Multituberculata?
What are some of the diversities among the Multituberculata?
1. One form appeared to be arboreal du to:
-it's Hallux (big toe) moved independendently
-Highly mobile ankle
-Possibly prehensile tail
2. Others semi-fossorial
3. Others saltitorial (jumpers)
Where were Order Gondwanatheriidae bones discovered?
South America, Madagascar, and Peninsular India
When was Order Gondwanatheriidae present?
Late Cretaceous but known only fm a few isolated, high crown teeth
When was Infraclass Triconodonta present?
Late Triassic to lower Cretaceous.
What did Tricondodonta stem from and who were there descendants?
Stemming fm among the oldest & most primitive mammals; left no descendants
What are the key characteristics of the Legion Symmetrodonta?
1. Numberous triangular molars (up to 6 lower M's) w/3 fairly symmetrically situated cusp
2. No angular process
A skeleton was found recently of a Symmetrodont in (where?) tt gives evidence tt Symmetrodonta is a side branch of Therians before the divergence of Meta and Eutheria. What 4 things suggest this?
1. Uncoiled cochlea
2. Presence of interclavical
3. Epipubic bones
4. Sprawled forelimbs
Roughly what size (comparative) is a Symmetrodont? It's diet type is probably what?
Shrew size and probably insectivorouse
When were the Superlegion Kuehneotheria around and where?
Late Triassic or Early Jurassic of Europe
When was Superlegion Symmetrodonta present?
Late Triassic to late Cretaceous
When was Sublegion Dryolestoidea present?
Late Jurassic to early Cretaceous
Describe in words the Tribosphenic molars
Multifunctional tooth wr protocone of 3 cusped upper molar fits into the talonid basin of lower tooth forming a grinding surface while the crest of other cusps shear past one another creating a shearing surface
What 3 features did the Sublegion Dryolestoidea have that are traceable to modern Therian mammals?
1. Structure of lower molars
a. Talonid
b. Trigonid
2. Tribosphenic molar
3. Angular process of dentary
Describe the molars of the Infralegion Peramura
Lower molars w/a distinct, posterior "heel" but no true talonid basin
What's the earliest tribosphenic molar in fossil record from?
Supercohort Aegialodontia. Lower molar has a talonid w/a basin into wc the protocone of upper molar fits