Herp Origins,
Evolution, & Classification
Herpetoculture
Pensacola Jr College
Herp Origins
w All tetrapods developed from
bony fish in:
w Class Osteichthyes
w Subclass Sarcopterygii (lobe-finned fishes)
w Order Actinistia (only living
member is the
coelacanth)
South American
lungfish
Coelacanth
Coelacanth
Coelocanth
Transitional Form
w First amphibian/tetrapod anscestor
was Ichthyostega
w Evolved in the Devonian
Period, approximately 370 million years ago
Ichthyostega
skeleton
Ichthyostega hind
limb
Ichthyostega
Life in
transition…
Transition of
Characters
Transition of
Characters
Diversification
w Amphibians and reptiles
diversified during the Carboniferous Period (about 300 million years ago)
w Common ancestral group split
off into 2 groups, one of which (amniota) radiated to an extreme
Evolutionary
Relationships
Ancestor
Amphibia Amniota
Therapsida
Anapsida
Diapsida
Mammals
Turtles Lepidosauria Archosauromorpha
snakes, lizards dinosaurs, crocs
tuatara birds
The
Archosauromorpha
w Living fossils: crocodilians
and birds
w
Ichthyosaurs?
w
Pterosaurs
w
Dinosaurs, eg:
•
Ceratopsia
•
Thyreophora
•
Theropoda
•
Sauropoda
Ichthyosaur
Pterosaur
Dinosaur -- Ceratopsia
Dinosaur -- Thyreophora
Dinosaur -- Theropoda
Dinosaur --
Sauropoda
What happened to
all these reptiles?
Classification
w Kingdom
w Phylum
w Class
w Order
w Family
w Genus
w Species