Trait
This presentation is the property of its rightful owner.
Sponsored Links
1 / 25

Trait Pelycosaurs Therapsids Cynodonts Posture:sprawlingintermediateupright PowerPoint PPT Presentation


  • 30 Views
  • Uploaded on
  • Presentation posted in: General

Trait Pelycosaurs Therapsids Cynodonts Posture:sprawlingintermediateupright Teeth:weakly heterodontincreasingly heterodontstrongly hetero Palate:no secondary palatepartialcomplete “-apsidy”small temporal fenestraenlarged fenestravastly expanded

Download Presentation

Trait Pelycosaurs Therapsids Cynodonts Posture:sprawlingintermediateupright

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Trait pelycosaurs therapsids cynodonts posture sprawling intermediate upright

TraitPelycosaursTherapsidsCynodonts

Posture:sprawlingintermediateupright

Teeth:weakly heterodontincreasingly heterodontstrongly hetero

Palate:no secondary palatepartialcomplete

“-apsidy”small temporal fenestraenlarged fenestravastly expanded

Postdentary bones:present, largepresent, reducedabsent

greatly reduced


Trait pelycosaurs therapsids cynodonts posture sprawling intermediate upright

cynodonts

Mammaliamorpha (transition to

dentary-squamosal joint begins)

Mammaliaformes

(formation of dentary-squamosal

“single jaw hinge” complete)

Mammalia: All descendants from

the MRCA of living mammals.


Trait pelycosaurs therapsids cynodonts posture sprawling intermediate upright

Mammalia

Mammaliaformes

Mammaliamorpha


Trait pelycosaurs therapsids cynodonts posture sprawling intermediate upright

Mesozoic

Morganucodon

Paleozoic

Mammalia (and some mammaliaforms)

  • Completion of dentary-squamosal jaw joint

  • Cheekteeth divided into premolars and molars

  • Diphyodonty

  • BUT TINY! For 170 million years!


Trait pelycosaurs therapsids cynodonts posture sprawling intermediate upright

cynodonts

Mammaliamorpha

Mammaliaformes

Mammalia: All descendants from

the MRCA of living mammals.


Trait pelycosaurs therapsids cynodonts posture sprawling intermediate upright

Multituberculates

(extinct prototherians)

Late Jurassic-Mid. Miocene

(ca. 150 m.y.)

Diverse, found on all continents

Ever-growing lower incisors,

plagialacoid (blade-like)

molariform teeth

Outcompeted to extinction?

(rodents, early primates...)


Trait pelycosaurs therapsids cynodonts posture sprawling intermediate upright

(INFRACLASSES)

Prototheria (SUBCLASS)

Metatheria

Eutheria

Theria

(SUBCLASS)

Mammalia (CLASS)

Mammaliaformes

Mammaliamorpha


Extant mammalian diversity

Extant mammalian diversity

Class MAMMALIA

Subclass Prototheria

Subclass Theria

Infraclass Metatheria

1 Order (Monotremata)

2 Families

3 5 species

7 Orders

19 21 Families

272 331 species

xx

x

xxx

Infraclass Eutheria

xx

18 21 Orders

114 130 Families

4354 5078 species

xxx

xxxx


The radiation of placental mammals

The radiation of placental mammals

Since end of Mesozoic, placental (eutherian) mammals dominant terrestrial vertebrates on all continents except Australia and Antarctica.

When and why did this diversification occur?


Trait pelycosaurs therapsids cynodonts posture sprawling intermediate upright

“Age of Mammals”

K/T boundary

“Age of Dinosaurs”


Trait pelycosaurs therapsids cynodonts posture sprawling intermediate upright

K/T

boundary


Trait pelycosaurs therapsids cynodonts posture sprawling intermediate upright

Most/all eutherian orders originated & diversify

AFTER K/T

(traditionally, fossils supported this)

Orders originate BEFORE K/T but don’t diversify until

AFTER K/T

(more recently discovered fossils support)

Most orders originate & diversify BEFORE K/T

(older molecular studies support)


Trait pelycosaurs therapsids cynodonts posture sprawling intermediate upright

Subclass Prototheria

1 Order (Monotremata)

2 Families

Tachyglossidae (echidnas or “spiny anteaters”)

4 species.

Ornithorhynchidae (platypus)

1 species


Trait pelycosaurs therapsids cynodonts posture sprawling intermediate upright

Subclass Prototheria

Few fossils, never very diverse. BUT PERSISTED.

Echidnas: fossils from 55-60 Mya, oldest in S. AMERICA

Platypus: fossils from 120 Mya, oldest in AUSTRALIA

(Paleocene fossils in S. AMERICA).

Many plesiomorphic features, but some apomorphies.


Trait pelycosaurs therapsids cynodonts posture sprawling intermediate upright

Subclass Prototheria

SKULL FEATURES:

•No teeth in living adults BUT fossil platys & living

neonates have, then lose. LOSS=apomorphy

•No lacrimals (APOMORPHY)

•Cranial sutures fused, indistinct (APOMORPHY)

•Jugal reduced or absent (APOMORPHY)


Trait pelycosaurs therapsids cynodonts posture sprawling intermediate upright

Subclass Prototheria

SKELETAL FEATURES:

•Epipubic bones present, large (PLESIOMORPHY)

•Cervical ribs (PLESIOMORPHY)

•Horny, hollow spur on inside of ankle (APOMORPHY)

•Pectoral girdle with large precoracoids, coracoids,

interclavicle (PLESIOMORPHY)

•Skeleton sprawling, “reptilian” (PLESIOMORPHY)

BUT, good for swimming, digging.


Trait pelycosaurs therapsids cynodonts posture sprawling intermediate upright

Warren et al. (2008). Nature 453, 175-183.


Trait pelycosaurs therapsids cynodonts posture sprawling intermediate upright

Subclass Prototheria

OTHER FEATURES:

•Pouch (echidnas only)

•Testes permanently abdominal (no scrotum)

•Uteri fused

•Leathery egg with nutrient-rich yolk

•Rostrum lacks vibrissae, elongate

•cloaca (but...)

•Endothermic, but low Tb and metabolic rates

•Electroreception (snout), including echidnas


  • Login