Xenarthra Flashcards Preview

Mammalian Diversity > Xenarthra > Flashcards

Flashcards in Xenarthra Deck (16)
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1
Q

Give the 2 orders contained within this super order.

A

Pilosa (anteaters, sloths)

Cingulata (armadillos)

2
Q

Where did the Xenarthra evolve ?

A

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

3
Q

Give the key adaption of this super group

A

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

4
Q

What adaptions do anteaters and sloths have for a low energy diet ?

A

Low metabolic rates
Able to vary temperature to reduce energy expenditure.
Sleep for majority of day to save energy supplies.

5
Q

How many species of ant eater exist ?

A

4 species

6
Q

Describe the feeding habits of anteaters.

A

No teeth,
Lap up insects with long tongue and sticky saliva
Gizzard like narrow region in stomach to crush insects.

7
Q

How many species of sloth exist ?

A

5

8
Q

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

A

2 and 3 toed sloths

Distinguished by number of fingers (all have 3 toes)

9
Q

Describe the feeding habits of sloths.

A
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
Q

Why do sloths have cyanobacteria in longitudinal grooves of hair ?

A

To act as a camouflage

11
Q

Describe the carapace of armadillos.

A

Develops from the skin

Composed of strong bony plates (scutes) overlaid by horn

12
Q

Give the number of armadillo species ?

A

21 species, ranging from 3 to 13 bands

13
Q

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

A

3 banded armadillo

14
Q

What is special about the armadillo penis ?

A

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

15
Q

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

A

3 families of giant ground sloths

size of elephants, mace on tail

16
Q

List the reasons these giant ground sloths disappeared

A

Climate change
Outcompeted by Eutherians
Human poaching and hunting