Diapsids Flashcards
Give the 2 living lineages of diapsid.
Lepidosaurs
Archosaurs
What is found within the Lepidosaurs lineage ?
Tuatara and Squamates
Give some of the features of the Lepidosaurs lineage ?
Largest group of non avian reptiles
Primarily terrestrial tetrapods
Reduction or loss of limbs
Scale covered skin, shed at intervals
When did the tuatara evolve ?
220 million years ago
How many species of Tuatara remain ?
2 species, due to human colonisation
Tuatara are lizard like, what is the defining difference between them ?
Tuatara have a heavier skull
Why is temperature important to tuatara ?
Determines the sex of the offspring.
Can propagate extinction process, (i.e higher temp- more males)
Describe key charecteristics of the tuatara life style.
Nocturnal (live in cool habitats)
Found in burrows- share with seabirds.
Dependant on seabirds for food
Sit and wait predators
Tutatara have a slow reproduction, describe this ?
Reach maturity at 10-20 years
Breed once every 4 years
Embryos take 11-14 months to hatch
What is the 3rd eye of the tuatara used for ?
Only present in young life
Absorbs UV light
What species are contained within the Squamata ?
Lizards and snakes
When did the squamates evolve ?
240 million years ago
Give the key features of the squamates
Vary in size, 16mm- 3m Highly kinetic skulls Scaly skin Legged and legless forms Worldwide distribution
What is the benefit of limb reduction to a diapsid ?
Advantages in habitats with narrowing openings
Beneficial on sand, tall grass and burrowing.
List the 6 indigenous UK squamate species
Smooth snake Sand lizard Common Lizard Grass snake Adder Slow worm
What is the other lineage, besides the Lepidosaurs ?
The Archosaurs
List the species, extant and extinct in the Archosaurs
Crocodillians
Pterosaurs
Dinasours, Birds
What main groups are contained within the crocodilians ?
Alligators and Crocodiles
How many species exist In the Crocodillians ?
23 living species
What habitat are the crocodilians confined to ?
Tropical and subtropical waters
Give an adaption of crocodiles and Gharials (fish eating croc) to marine environments
Modified salivary glands on their tongues for excreting excess salt
What do Alligators and Caimans have that is also found in Gharials and crocodiles ?
The same modified salivary gland for secretion of salt.
However it is non functioning
All crocodiles are Gastroliths, what does this mean ?
They have a stomach stone
Acts as a grinder to aid prey digestion
How many stomach do crocodiles have ?
2 stomachs
1st is muscular to grind prey
2nd is acidic to digest bones, feathers and horns
State the number of species in the Alligatoridea.
8 species
State the number of species in the Crocodylidae.
13 species
State the number of species in the Gavialidae
2 species
Gharial and the false gharial
