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Flashcards in Xenarthra Deck (16)
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1

Give the 2 orders contained within this super order.

Pilosa (anteaters, sloths)
Cingulata (armadillos)

2

Where did the Xenarthra evolve ?

Isolated on south America,
Huge adaptive radiation between 65 to 2.5 MYA
Most species still found here today.

3

Give the key adaption of this super group

Reduced teeth or lost
Large claws on toes
(Biggest anteater)
Diet low in energy content

4

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.

5

How many species of ant eater exist ?

4 species

6

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.

7

How many species of sloth exist ?

5

8

Sloths are grouped into 2 families, How are they split ?

2 and 3 toed sloths
Distinguished by number of fingers (all have 3 toes)

9

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.

10

Why do sloths have cyanobacteria in longitudinal grooves of hair ?

To act as a camouflage

11

Describe the carapace of armadillos.

Develops from the skin
Composed of strong bony plates (scutes) overlaid by horn

12

Give the number of armadillo species ?

21 species, ranging from 3 to 13 bands

13

Which species of armadillo can roll themselves into a ball for protection ?

3 banded armadillo

14

What is special about the armadillo penis ?

It is 2/3rds of the body width, required to get round the armour of the female

15

Which 3 families of Xenarthra were present 38 million years ago ?

3 families of giant ground sloths
(size of elephants, mace on tail)

16

List the reasons these giant ground sloths disappeared

Climate change
Outcompeted by Eutherians
Human poaching and hunting