Slide 1 Order rodentia a. More than 426 genera, 2010+ species Slide Rodents




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Slide 1 Order RODENTIA

A. More than 426 genera, 2010+ species


Slide 2. Rodents

  1. Nearly cosmopolitan in distribution

  2. Exploit a broad variety of foods and habitats

Slide 3. Why so successful?



  1. High fecundity

  2. high population densities

  3. Rapid population turnover

  4. Usual small size

  5. Highly efficient jaws and dentition

  6. Repeated adaptive radiations

Slide 4. Order RODENTIA



  1. Characters

    1. single pair of curved, evergrowing incisors with enamel restricted to the anterior face

    2. long diastema

Slide 5. Dental division of labor



  1. Incisors




  1. Cheek teeth

Slide 6. Skull Types


Slide 7. Jaw Musculature
Slide 8. Protrogomorphous

Slide 9. Sciuromorphous

Slide 10. Hystricomorphous

Slide 11. Myomorphous

Slide 12. Jaw Angle


  1. Sciurognathous



  1. Hystricognathous

Slide 13. Dentitions


Slide 14. Family APLODONTIDAE



  1. Endemic to western North America




  1. Only protrogomorphous extant rodent.

Slide 15. Aplodontia rufa

Slide 16. Family SCIURIDAE


  1. Cosmopolitan except Australian, Madagascar

  2. 50 genera; 273 species

  3. Sciuromorphous

Slide 17: Pictures of Sciuridae


Slide 18. ‘Flying’ squirrels

A. glissant


Slide 19 Ground squirrels

  1. semifossorial

Slide 20. Bernoulli Goes Underground



  1. Prairie dog warrens



  1. Bernoulli’s principle

    1. higher places are windier




    1. atmospheric pressure is reduced

Slide 21. Family CASTORIDAE



  1. Holarctic: 2 species.

  2. Sciuromorphous, sciurognathus.

Slide 22. Castoridae



  1. Large size, reach 30+ kg.

  2. Tail Slapping

Slide 23. Semiaquatic Adaptations



  1. fine, dense underfur

  2. hind feet webbed

  3. nictating membrane

  4. valvular nostrils and ears.

  5. epiglottis is above the soft palate

Slide 24. Behavior



  1. social and family-oriented




  1. monogamous

Slide 25. Castor gland

Slide 26. Environmental Modification

A. Beaver ponds and lodges


Slide 27. Beaver ponds

  1. Modify environment

  2. Form extensive wetlands

  3. Etc.

Slide 28. Keystone Species



  1. Increase biodiversity




  1. Positive effects




  1. Negative effects

Slide 29. Conservation


Slide 30. Castoroides

Slide 31. Family GEOMYIDAE


  1. Nearctic, Neotropical (northern Columbia)

  2. 5 genera, 35 species

  3. Sciuromorphous

  4. external, furred cheekpouches

Slide 32 Family Geomyidae



  1. fossorial adaptations and diet

Slide 33. Family HETEROMYIDAE

  1. Nearctic and northern Neotropical (Columbia, Venezuela)

  2. Sciuromorphous

  3. external, furred cheekpouches

  4. granivores

Slide 34. Xeric adaptations

1.
2.
3.
4.
5.
Slide 35. Dipodomys

Slide 36. Family MURIDAE



    1. Cosmopolitan

    2. family constitutes 66% of all rodents

    3. >1/4 of all mammal species

    4. 281 genera, 1325 species

    5. myomorphous

Slide 37. Systematics



  1. 17 subfamilies, including

    1. Murinae

    2. Sigmodontinae

    3. Arvicolinae

Slide 38. Subfamily Murinae



  1. Old World rats and mice

  2. 117+ genera, 529+ species

  3. Palearctic, Oriental, Ethiopian, Oceanic

Slide 39. Negative Impact

Slide 40. Positive Impact

Slide 41. Subfamily Sigmodontinae



  1. New World rats and mice.

  2. 73+ genera, 422+ species.

  3. 85% of species are South American.

Slide 42. Sigmodontinae



  1. Peromyscines




  1. Sigmodontines

Slide 43. Subfamily Arvicolinae



  1. voles, lemmings, and muskrats

  2. Holarctic grazers

Slide 44. Population cycles

Slide 45. Why cycling lemmings crash – John Whitfield

Slide 46. Why cycling lemmings crash – John Whitfield


Slide 47. The Far Side: Lemming Migration

Slide 48. Hystricognathi


  1. hystricognathous

  2. K-selected

  3. Highly specialized: small litter size (1 - 2); mostly precocious young (hairy and eyes open at birth

  4. Distribution

Slide 49 Family HYDROCHOERIDAE


Slide 50. Hydrochoerus

  1. Largest living rodent (up to 65 kg).

  2. Ecomorph of pygmy hippopotamus

  3. Hunted for meat and their hide.

Slide 51. Family Caviidae



  1. grasslands and savannas of South America

  2. Patagonian hare:

Slide 52. Family MYOCASTRORIDAE


Slide 53. Myocastoridae

  1. Introduced as furbearer and for aquatic weed control into North America and Europe




  1. Federal and local nutria control programs

Slide 54. Family Agoutidae

A. pacas
Slide 55. Agoutidae

A. expanded zygomatic arches may be resonating chambers to amplify sounds.


Slide 56. Convergent evolution in porcupines

  1. Hystricidae




  1. Erethizontidae

Slide 57. Dinomyidae

A. Phoberomys pattersoni, a 680-kilogram rodent that roamed South America eight million years ago.
Slide 58. Pedetidae


  1. Springhaas or Cape jumping hare

Slide 59. Bathyergidae



  1. African mole-rats

  2. Fossorial

Slide 60. Heterocephalus the naked mole rat


Slide 61. Heterocephalus and Cryptomys

  1. colonial, up to 40 individuals

  2. Inhabit hot, dry environments: dig extensive burrows to find food

  3. Eusocial

Slide 62 EUSOCIALITY in Heterocephalus


Slide 63. Order LAGOMORPHA

  1. 13 genera, 80 species

  2. Family Ochotonidae

  3. Family Leporidae

Slide 64. Lagomorpha



  1. distribution is nearly worldwide.

  2. Introduced to Australia

Slide 65. Attempt to control Australian rabbits

A. Myxomatosis
Slide 66. Distinguishing between leporids and rodents
Slide 67. Skull and dentition


  1. Two upper incisors

  2. fenestration

Slide 68. Family Ochotonidae - pikas



  1. 2 genera, 26 species

  2. Not cursorial

Slide 69. Pika behavior.

Slide 70. Family Leporidae


  1. Hares and rabbits

  2. 11 genera, 54 species

  3. Diverse habitats

Slide 71. Ecology & behaviour

A. cursoriality

Slide 72. Reproduction



  1. polyestrous




  1. Altricial




  1. Precocial

Slide 73. Diet



  1. coprophagy

Sllide 74. Family Leporidae



  1. Seem to occupy a niche as miniature ungulates,

  2. Competition with ungulates may have hindered diversification


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