Rodentia Flashcards
-Know all families in Colorado -Know special feature (why K-rats don't drink) -Know general features
1
Q
Rodentia
A
- Largest mammalian order
- Occupy broad variety of habitats and eat various kinds of foods
- Inhabit all continents except Antarctica
2
Q
Fossil Record
A
- Rodent-like reptiles first appear in late Triassic
- Appears rodent were Triylodonts, gave rise in multituberculates in late Jurassic
- Oldest known member of Rodentia is a sciuromorph (Paramyidae)
3
Q
Why were they so successful?
A
- High fecundity
- High population densities
- Rapid population turnover
- Small size, efficient jaws and dentition
- Had repeated adaptive radiations
4
Q
Characteristics of Rodentia
A
- Females have duplex uterus and males have a baculum
- Jaw muscles: Sciuromorphous, Myomorphous, and Hystricomorphous
5
Q
Dentition
A
- Ever growing incisors, w/ enamel restricted to anterior face of teeth
- Long diastema
- No canines
- Dental formula: 1/1,0/0,0/0,3/3
- No species have more than 22 teeth except the mole rat
6
Q
7 Colorado Families
A
- Sciuridae
- Geomyidae
- Castoridae
- Heteromyidae
- Muridae
- Dipodidae
- Erethrizontidae
7
Q
Sciuridae
A
- Ground squirrels and marmots
- Abert’s, red, and fox squirrel
- Prairie dogs
- Chipmunks
- Diurnal herbivores
8
Q
Geomyidae
A
- Pocket gophers
- Nearctic and Neotropic (northern Columbia)
- Sciuromorphous
- External, furred cheek pouches
- Sense of touch in important
9
Q
Plains Pocket Gopher
A
- Solitary rodent that live their life underground in tunnels nearly all their life
- Built for digging
- In spring 1-6 pups are born
- Usually live less than 5 years
10
Q
Heteromyidae
A
-Kangaroo rats and pocket mice
11
Q
Why don’t Kangaroo Rats ever drink?
A
- Water produced metabolically within cell during oxidation of foodstuff
- No sweat glands=no water loss
- Longer loops of Henle in kidneys allow urine to get very concentrated and keep water in body longer
12
Q
Castoridae
A
- Semiaquatic
- Sciurognathus jaw
- Cheekteeth hypsodont but not evergrowing
- Nictating membrane protects eye in swimming
13
Q
Muridae
A
-Rats, mice and voles
14
Q
Vole Clock
A
- Exhibit complex genetic structure w/ variation that appear to be evolving rapidly compared to other vertebrates
- Method of dating archeological strata
15
Q
Dipodidae
A
- Jumping mice, jerboas, and birch mice
- Omnivorous w/ diet of seeds and insects
- 1/1,0/0,1/1,3/3=20
