Lab 5: Rodentia and Lagomorpha
(8 families in B.C.) Sciuridae squirrels (16 species in B.C.) Muridae mice, rats, lemmings, voles (16) Aplodontidae mountain beaver (1) Castoridae beaver (1) Dipodidae jumping mice (2) Erethizontidae N. American porcupines (1) Geomyidae pocket gophers (1) Heteromyidae kangaroo rats, pocket mice (1)
Incisors Single pair of upper, single pair of lower Enamel on anterior surface, not posterior surface Diastema No canines
Family Sciuridae Postorbital process well-developed Infraorbital foramen reduced - usually small and round
Family Sciuridae Postorbital process well-developed Infraorbital foramen reduced - usually small and round 4-5 cheekteeth anterior premolar sometimes small and peg-like usually with transverse ridges
Family Muridae Infraorbital foramen usually V-shaped (wider above)
Family Muridae Infraorbital foramen usually V-shaped (wider above) 2-3 cheekteeth Prismatic with folds of enamel or cuspidate with 2-3 longitudinal rows
Family Aplodontidae Aplodontia rufa (mountain beaver) Namanu Outdoor School
Family Aplodontidae Aplodontia rufa (mountain beaver) Infraorbital foramen small and round 5 cheekteeth Prominent outer projections Auditory bullae flask-shaped
Family Aplodontidae Aplodontia rufa (mountain beaver) Most primitive rodent Not closely related to the beaver, despite the name Range: western B.C.
Family Castoridae Castor canadensis (American beaver)
Family Castoridae Castor canadensis (American beaver) Infraorbital foramen small and slit-like 4 cheekteeth Distinctive transverse folds Broad jugal Incisors massive Bony tube surrounding external auditory meatus
Family Castoridae Castor canadensis (American beaver) Largest rodent in North America Create extensive lodges Range: throughout B.C.
Family Dipodidae (jumping mice)
Family Dipodidae Zapus spp. (jumping mice) Greatly enlarged infraorbital foramen 4 cheekteeth Upper premolar small and peg-like Grooved incisors
Family Dipodidae Zapus trinotatus (Pacific jumping mouse) crescent-shaped fold on upper premolar
Family Dipodidae Zapus hudsonius (meadow jumping mouse) No fold on upper premolar
Family Dipodidae Zapus spp. (jumping mice) Most closely related to species in Europe, Africa, and Asia Very long tail and hind feet Range (Z. hudsonius): most of B.C. except the coast Range (Z. trinotatus): extreme southwestern B.C.
Family Erethizontidae Erethizon dorsatum (N. Amer. porcupine)
Family Erethizontidae Erethizon dorsatum (N. Amer. porcupine) Greatly enlarged infraorbital foramen 4 cheekteeth Wide re-entrant folds Enlarged auditory bullae Massive incisors
Family Erethiontidae Erethizon dorsatum (N. Amer. porcupine) Spines! Can survive up to 18 years in the wild. Range: throughout B.C.
Family Geomyidae Thomomys talpoides (Northern pocket gopher) U.S. Forest Service
Family Geomyidae Thomomys talpoides (Northern pocket gopher) Infraorbital foramen small and round on side of rostrum 4 cheekteeth Premolars 8-shaped Massive incisors premolar
Family Geomyidae Thomomys talpoides (Northern pocket gopher) External fur-lined cheek pouches Fossorial Construct one burrow per individual Closed tunnel entrances Range: southern B.C.
Family Heteromyidae Perognathus parvus (Great Basin pocket mouse) Mark Chappell
Family Heteromyidae Perognathus parvus (Great Basin pocket mouse) Large infraorbital foramen on rostrum 4 cheekteeth 2-lobed pattern Grooved upper incisors Enlarged auditory bullae almost touch anteriorly
Family Heteromyidae Perognathus parvus (Great Basin pocket mouse) External, fur-lined cheek pouches Range: southern B.C.
Order Lagomorpha www.borealphoto.com
Order Lagomorpha 4 upper incisors (2 pairs) Diastema No canines
Order Lagomorpha Family Ochotonidae (pikas) No supraorbital process 5 upper cheekteeth on each side
Order Lagomorpha Family Ochotonidae (pikas) 2 species in B.C. Ochotona collaris (collared pika) Ochotona princeps (American pika) Mountainous areas Thought that local extinctions possible because of climate change Range (O. collaris): extreme northwestern B.C. Range (O. princeps): southern half of B.C.
Order Lagomorpha Family Leporidae (rabbits and hares) Supraorbital process 6 upper cheekteeth on each side
Order Lagomorpha Family Leporidae (rabbits and hares) Lepus americanus (snowshoe hare) Lepus townsendii (white-tailed jackrabbit) No interparietal Broader postorbital process
Lepus americanus Lepus townsendii Lepus townsendii Lepus americanus
Order Lagomorpha Family Leporidae (rabbits and hares) Lepus americanus (snowshoe hare) Summer dorsal pelage brown, winter pelage white Range: throughout B.C. Lepus townsendii (white-tailed jackrabbit) Range: extreme south-central B.C.
Order Lagomorpha Family Leporidae (rabbits and hares) Sylvilagus floridanus (eastern cottontail) Sylvilagus nuttalli (mountain cottontail) Distinct interparietal Narrower postorbital process
Sylvilagus nuttalli Sylvilagus floridanus
Order Lagomorpha Family Leporidae (rabbits and hares) Sylvilagus floridanus (eastern cottontail) Range: extreme southwestern B.C. Sylvilagus nuttalli (mountain cottontail) Range: extreme south-central B.C.