Lecture 18- Rodents Flashcards Preview

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Flashcards in Lecture 18- Rodents Deck (25):
1

What percentage of Australian terrestrial mammals are rodents?

22%

2

How many species does the order Rodentia have?

-2300
-45% of all mammals

3

When did rodents evolve?

-65 MYA (mammals 195 MYA)

4

What are the key features of rodents?

-molariform teeth (premolars and molars)= squarish teeth for grinding
-diastema= gap between incisors and premolars
-incisors (continuously growing and large)

5

What is the weight range of rodents?

-4g (pygmy jerboa) to 66kg (capybara)

6

What order are rats and mice etc. in?

-Supraorder Muroidea

7

What are the two main orders of rats and mice (Muroidea)?

-1 Murinae (620+ species, 11% of mammals, origin 12 MYA)
2. Sigmodontinae (380+ species, 7% of mammals)

8

How did rodents get to Australia?

-crossed into Australia twice
-once 5 million yrs ago and then more recent (1 million yrs ago)
-from Asia (and PNG)

9

What order are all the rodents in Australia?

Murinae

10

What is the Wallace's line?

-Wallace’s line= because the land masses were never connected in the last 10 million years, that is why different animals on each side
-deep ocean

11

What are the second wave rodent colonizers?

-genus Rattus
-Second Colonizers •Pleistocene (~1 Ma) •25+ Species •Little morphological variation •High reproductive rates
•(8-12 teats)

12

Who are the first wave colonizers and how do you identify them?

-old endemics
-have 4 teats
First Colonizers
•Pliocene (~5 Ma)
•160+ Species
•Large ecological and morphological variation
•Low reproductive rates •(4 teats)

13

What are the characteristics of the Anisomyni?

New Guinea Endemics 12 genera Australia 1 genus, 1 species
-large terrestrial

14

What are the characteristics of Pogonomys?

-arboreal

15

What are the characteristics of Hydromini?

-the aquatic and terrestrial carnivores
-10 genera Australasia Australia 2 genera, 2 species

16

What are the characteristics of the Uromyini?

Generalized ‘rats’ 4 genera Australasia Australia 2 genera, 6 species
-live in wet tropics rainforest
-the other live in rainforest, grasslands and monsoon tropics
-600-700g

17

What are the characteristics of the Conilurus species group?

-Australian Endemics 3 genera, 6 species, 2 recently extinct
-tree rats
-stick nest rats (build stick nests)
-rabbit rats

18

What are the characteristics of the Pseudomys species group?

-Australian Endemics 5 Genera, 42 species
-live everywhere
Pseudomys= biggest group in Australia
Pseudomys= everywhere except the tropics
-then Australian lemming-grass feeding
-rock rats
-hopping mouse
-short tail rats
-false mice

19

How many species are there in the genus Rattus?

7 species (+2 extinct from Christmas Island) 18+ species New Guinea
--bush rat= one of the most widespread

20

Why is there so much diversity in rodents? (Muronia)

-adaptable, live in diverse habitats,diversify in form as they colonize
-hopping mice = in American and Australia=== developed independently
-converge in having one of the most efficient kidney= never need to drink water, get it from break down of fats

21

Are rodents declining in Australia?

-some are
-29% of species are in decline

22

What is the situation with Leporillus apicalis and Leporillus conditor?

-Leporillus apicalis=EXTINCT
-Leporillus conditor= Extinct on mainland Captive breeding, Reintroduction, only in Franklin island now

23

Why does colonization lead to the diversification of species and forms?

1.Ecological opportunity
2.Key Innovation
3.Morphological Disparity

24

What is the story with the Australian stick nest rat and the American Wood Rat?

-both build stick nests
-stick nest rats= build stick nets to protect from carnivores
-wood rats= independently developed wood nests that are passed down the generations and protect them

25

What is special about the Sulawesi Paucidentomys vermidax?

Carnivore =don’t have chiseling incisors as they should
Their teeth don’t wear as much
-no molar teeth (unlike other rodents)
-this development of teeth happened in a few other species (one in the philippines)
-they are not closely related
-the water rats also not closely related
-high convergence in rats