THE FINAL BABY. Flashcards
who is in Superorder Archosauria?
- crocodylomorpha (crocodiles and their relatives)
- dinosauria (dinosaurs including birds)
what happens if we add turtles as a basal/sister taxon to the Superorder Archosauria?
- we get a larger EXTANT clade referred to as Archosauromorpha
- this is why turtles are the only non-archosaurian archosauromorphs!
what order are all modern turtles in?
order testudinea
what are the suborders in order testudinea?
cryptodira and pleurodira
Describe the Suborder Cryptodira
- means hidden neck
- they are more widespread and diverse
- found in the northern and Southern Hemispheres
- NOT found in Australia
Describe the Suborder Pleurodira
- means side neck
- restricted to southern hemisphere currently, but were worldwide during Mesozoic and Cenozoic eras
Describe the Suborder Cryptodira
- means hidden neck
- more widespread and diverse
- found all over (not in Australia)
what is the carapace?
-the fusion between vertebrae and ribs
what makes the turtle morphology unique?
- their shell
- relocated shoulders and pelvises
describe the different pelvic morphologies of Pleurodira and Cryptodira turtles
Pleurodira: the pelvic assembly is fused to the carapace
Cryptodira: the pelvic assembly is not fused to the carapace
Neck retraction in Pleurodires and Cryptodires
- cryptodires have a high degree of vertebral flexibility and use the “vertical S bend” to hide their necks
- pleurodires have a longer neck and hide their neck using the “horitontal bend”
Family Dermochelyidae
- shell is reduced to thousands of small bones embedded in leathery skin
- contains the largest diapsids in this order (leatherback turtle)
Leatherback Turtle
- in family dermochelyidae
- fusion of vertebral elements different from other turtles
- because they are so large, they are able to save heat and therefore can survive where other turtles cannot
Family Cheloniidae
- the sea turtles!
- bony shells covered with epidermal scutes and paddle like forelimbs
- found world wide in tropical and temperate waters
Why are the Alligator Snapping Turtle and Sea Turtle so different, even though they both spend a majority of their life in water?
- they had different predators to evade, the AST had the alligator, while the sea turtles have sharks.
- also, AST are ambush predators and did not need to evolve to be hydrodynamically efficient
Family Chelydridae
- found in north and Central America
- large freshwater turtles
- alligator snapping turtle or common snapping turtle
Alligator Snapping Turtle
- purely ambush predator
- utilizes a lingual lure
- slow and heavy, not hydrodynamically efficient
Family Testudinidae
- tortises (mostly terrestrial)
- worldwide distribution in tropical and temperate climates
- NOT good swimmers
- designed to dig: heavily armored, flat paddle like limbs
- not much of a hinge, which means they can’t seal the plastron and use their limbs instead
When we see a turtle in family Testudinidae with a plastron, we know they are…
male!
Family Emydidae
- box turtles and cooters
- mostly in North America
- highly domed carapace (making it difficult for predator to bite)
- strongly hinged plastron
- not hydrodynamically efficient
Diamondback Terrapin
- unique Emydidae species
- flat shell with paddle like limbs (more hydrodynamic)
- males have long nails
Family Trionychidae
- soft shell turtles
- found in North America, Asia, and Africa
- basal lineage (ancestral)
- less fusion in ribs
- no keratinized outer cover
How are the soft shell turtles able to breathe under water?
projections at the back of the throat that are fleshy and highly vascularized
what are the male turtle morphologies?
- long penises
- long nails (aquatic species)
- spur on plastron
what are the archosauria synapomorphies?
- prescense of ant orbital fenestra
- orbit shaped like inverted triangle
- laterally compressed teeth
- 4th trochanter on femur
pseudosucha leads to…
- “such” relates to crocodylomorpha
assumed archosauria synapomorphies
- four chambered heart
- muscular diaphragm
- nest building/parental care
having laterally compressed teeth allowed carnivorous archosaurids to have…
serrations on their teeth
archosauria splits into two groups;
ornithodira (Dinos and birds) and pseudosuchia (crocs)
what does archosauromorpha split into?
the turtles and archosauria (dinos, birds, and crocs)
describe pangea prior to its split
pangea was one supercontinent surrounded by ocean, most of which were deep ocean basins.
deep ocean basins function as “heat sinks”, pulling heat out of the atmosphere. the climate had adapted to that but when pangea broke apart there were more shallow, tropical, marine waters releasing heat back into the atmosphere, warming it
what cause the end of Triassic extinction, and what were the results?
the change in environment and splitting of populations and possibly a meteor caused the extinction, which resulted in a mass extinction. pseudosuchia, which was previously very diverse all went extinct except for crocodylomorpha
all modern crocs are in…
neosuchia
what are the alligator families?
- alligatoridae
- crocodylidae (most diverse)
- gavialidae
crocodylian modes of locomotion
- lateral undulation (ancestral)
- belly crawl
- high walk
- gallop (rare and only in members of F. Crocodylidae)
What morphology is important for the high walk mode of locomotion in crocodylians?
the ankle and wrist joints can flex up and down AND laterally
reproductive behaviors of crocodylomorphs
- nest builders (mounds keep constant temperature)
- high degree of parental care (protection, providing food sources)
- creche: an area with babies from multiple females who then take turns taking care of the babies
predatory behaviors of crocodylomorphs
- generalist carnivores
- oportunistic
- ambush predators
- wait at high traffic areas
- “tool use”, luring in birds with sticks on snout