Xenarthra Flashcards
Give the 2 orders contained within this super order.
Pilosa (anteaters, sloths)
Cingulata (armadillos)
Where did the Xenarthra evolve ?
Isolated on south America,
Huge adaptive radiation between 65 to 2.5 MYA
Most species still found here today.
Give the key adaption of this super group
Reduced teeth or lost
Large claws on toes
(Biggest anteater)
Diet low in energy content
What adaptions do anteaters and sloths have for a low energy diet ?
Low metabolic rates
Able to vary temperature to reduce energy expenditure.
Sleep for majority of day to save energy supplies.
How many species of ant eater exist ?
4 species
Describe the feeding habits of anteaters.
No teeth,
Lap up insects with long tongue and sticky saliva
Gizzard like narrow region in stomach to crush insects.
How many species of sloth exist ?
5
Sloths are grouped into 2 families, How are they split ?
2 and 3 toed sloths
Distinguished by number of fingers (all have 3 toes)
Describe the feeding habits of sloths.
Arboreal, leaf eating lifestyle Few competitors Cellulose digesting bacteria in stomach Can process meal for 1 month Excrete urine and faeces 1 a week.
Why do sloths have cyanobacteria in longitudinal grooves of hair ?
To act as a camouflage
Describe the carapace of armadillos.
Develops from the skin
Composed of strong bony plates (scutes) overlaid by horn
Give the number of armadillo species ?
21 species, ranging from 3 to 13 bands
Which species of armadillo can roll themselves into a ball for protection ?
3 banded armadillo
What is special about the armadillo penis ?
It is 2/3rds of the body width, required to get round the armour of the female
Which 3 families of Xenarthra were present 38 million years ago ?
3 families of giant ground sloths
size of elephants, mace on tail
