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25 Cards in this Set
- Front
- Back
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Where did mammals originate from and was this mono or polyphyletic?
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Monophyletically from Cynodont Synapsids
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What were the 2 groups of animals that are considered a sister group of mammals and are extremely close to being mammalian?
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1. Sinoconodon (Early Jurassic of Asia)
2. Adelobasileus (Late Triassic of N.Am., known only fm a braincase |
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Mammaliaformes are considered mammals; what is the Mammaliaforme Order called?
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1. Order Morganucodontidae
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When was Order Morganucodontidae (Mammaliaformes) present and where?
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Late Triassic or Early Jurassic of Europe
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What is the earliest known mammal (Order)?
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Order Morganucodontidae
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When was the Order Multituberculata (Infraclass Allotheris-Subclass Theriformes) present?
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1. Existed 100 million yrs fm late Jurassic well into Eocene
2. By late Cretaceous & Paleocene, was widespread in Old & New Worlds (Holoarctic diestribution) |
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What are the characteristics of Order Morganucodontidae?
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.
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When did the Multituberculata disappear?
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In Eocene; probably due to rapid development of rodents after already suffering competition from the Condylarths and primates
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What were the advanced characteristics of the Multituberculata?
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1.Molars w/parallel rows of cusps (grinding)
2.Lower premolar-specialized blade like tooth 3. Jaw rodent-like: -1/1I -Diastma -Molars highly specialized |
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What were the primitive characteristics of Multituberculata?
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.
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What are some of the diversities among the Multituberculata?
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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) |
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Where were Order Gondwanatheriidae bones discovered?
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South America, Madagascar, and Peninsular India
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When was Order Gondwanatheriidae present?
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Late Cretaceous but known only fm a few isolated, high crown teeth
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When was Infraclass Triconodonta present?
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Late Triassic to lower Cretaceous.
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What did Tricondodonta stem from and who were there descendants?
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Stemming fm among the oldest & most primitive mammals; left no descendants
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What are the key characteristics of the Legion Symmetrodonta?
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1. Numberous triangular molars (up to 6 lower M's) w/3 fairly symmetrically situated cusp
2. No angular process |
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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?
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1. Uncoiled cochlea
2. Presence of interclavical 3. Epipubic bones 4. Sprawled forelimbs |
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Roughly what size (comparative) is a Symmetrodont? It's diet type is probably what?
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Shrew size and probably insectivorouse
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When were the Superlegion Kuehneotheria around and where?
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Late Triassic or Early Jurassic of Europe
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When was Superlegion Symmetrodonta present?
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Late Triassic to late Cretaceous
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When was Sublegion Dryolestoidea present?
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Late Jurassic to early Cretaceous
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Describe in words the Tribosphenic molars
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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
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What 3 features did the Sublegion Dryolestoidea have that are traceable to modern Therian mammals?
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1. Structure of lower molars
a. Talonid b. Trigonid 2. Tribosphenic molar 3. Angular process of dentary |
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Describe the molars of the Infralegion Peramura
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Lower molars w/a distinct, posterior "heel" but no true talonid basin
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What's the earliest tribosphenic molar in fossil record from?
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Supercohort Aegialodontia. Lower molar has a talonid w/a basin into wc the protocone of upper molar fits
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