LAB #7
SKINS AND SKULLS OF XENARTHRA, CARNIVORA, PERISSODACTYLA, AND ARTIODACTYLA
In this lab, you will learn to identify the skins and skulls of the mammals
listed below. You also will be responsible for both scientific and common names
during a quiz at the end of the lab period. I will provide characteristics for
the skins and the skulls but you can also see the STUDY AID FOR SKULLS given
below to find the distinguishing characteristics of the skulls. You should work
on these characteristics PRIOR TO the lab period.
SKINS
Dasypus novemcinctus
Canis latrans
Vulpes vulpes
Vulpes velox
Urocyon cinereoargenteus
Procyon lotor
Bassariscus astutus
Taxidea taxus
Mephitis mephitis
Lynx rufus
Odocoileus virginianus
Odocoileus hemionus
SKULLS
Dasypus novemcinctus
Canis latrans
Canis lupus
Vulpes vulpes
Vulpes velox
Urocyon cinereoargenteus
Ursus americanus
Ursus arctos
Procyon lotor
Bassariscus astutus
Mustela vison
Lontra canadensis
Taxidea taxus
Mephitis mephitis
Puma concolor
Lynx rufus
Odocoileus hemionus
Odocoileus virginianus
Antilocapra americana
Bison
bison
INTRODUCED SPECIES
Equus caballus
Bos taurus
Ammotragus lervia
STUDY AID FOR SKULLS
ORDER XENARTHRA
Dasypodidae
Dasypus novemcinctus (nine-banded armadillo)
1. narrow tubular rostrum
2. uniform peg-like teeth with no enamel
3. teeth not present in anterior part of jaws
4. 28-36 teeth (DF = 0/0, 0/0, 7-9/7?9)
ORDER CARNIVORA
Canidae-rostrum elongate and narrow, enlarged canines, well?developed carnassials (first lower molar, last upper premolar), 42 teeth (DF = 3/3, 1/1, 4/4, 2/3)
Canis latrans (coyote)
1. postorbital process thickened convex dorsally
2. elongate rostrum
3. ventral border of dentary without stepCanis lupus (gray wolf)
1. similar to C. latrans but larger, heavier
2. pronounced frontal more convex than C. latransVulpes vulpes (red fox)
1. temporal ridges converge to form "v" shape
2. depressions on postorbital processes
3. total length less than 160 mm
4. ventral border of dentary without stepVulpes velox (swift fox)
1. temporal ridges bow out laterally half way back
2. depressions on postorbital processes
3. first two incisors in straight horizontal line; third farther back
4. total length less than 160 mmUrocyon cinereoargenteus (gray fox)
1. temporal ridges converge to form "u" shape
2. deep depressions on postorbital process
3. length of skull approximately 130 mm
4. ventral border of dentary with prominent step
Ursidae-enlarged canines, no well developed carnassial pair, skull is more cat-like
than dog-like (rostrum is short), 42 teeth (DF = 3/3, 1/1, 4/4, 2/3)Ursus americanus (black bear)
1. molars with flat, broad crown
2. diastema on lower jaw
3. hard palate extends beyond molarsUrsus arctos (grizzly bear)
1. similar to Ursus americanus but larger
2. prominent sagittal crestProcyonidae-40 teeth, molars 2/2, carnassials not well developed except in Bassariscus
Procyon lotor (raccoon)
1. poorly developed carnassials
2. molars broad, canines round
3. palate extends beyond last molars
4. skull rounded on upper surfaceBassariscus astutus (ringtail)
1. palate terminates just posterior to last molar
2. upper molars transversely elongated, much broader than long
3. greatest length of skull is 77.2 mm
4. postorbital process generally more pronounced than in ProcyonMustelidae-teeth 38 or less, molars 1/2, enlarged canine, short rostrum, carnassial pair
Mustela frenata (long-tailed weasel)
1. palate extends beyond last molar
2. total length of skull less than 55 mm
3. inflated auditory bullae
4. postorbital processes pointed
5. upper molar dumbbell shaped
6. braincase is elongated
7. upper surface of skull is flat
8. 34 teeth (DF = 3/3, 1/1, 3/3, 1/2)Mustela nivalis (least weasel)
1. similar to Mustela frenata except smaller
2. total length of skull less than 35 mmMustela vison (mink)
1. total length greater than 55 mm
2. blunt postorbital processes
3. upper molar dumbbell shaped
4. inflated auditory bullae
5. 34 teeth (DF = 3/3, 1/1, 3/3, 1/2)Taxidea taxus (badger)
1. skull triangular in shape, broadest posteriorly
2. prominent sagittal crest and lambdoidal crest
3. last two molars triangular in shape
4. palate extends beyond molars
5. obviously inflated auditory bullae
6. 34 teeth (DF = 3/3, 1/1, 3/3, 1/2)Lontra canadensis
1. postorbital process well developed
2. infraorbital foramen large and roughly oblong
3. auditory bullae not inflatedMephitidae- molars 1/2, palate does not extend beyond last molar, carnassial pair, short rostrum
Mephitis mephitis (striped skunk)
1. palate not extended beyond last molar
2. auditory bullae concave
3. frontal bone rounded, skull convex above
4. mastoid region not inflated
5. notch in lower posterior edge of dentary
6. last molar not dumbbell shaped
7. prominent sagittal crest
8. 34 teeth (DF = 3/3, 1/1, 3/3, 1/2)Spilogale putorius (eastern spotted skunk)
1. palate not extended beyond last molar
2. frontal bone flattened
3. mastoid region inflated; inflated appearance to braincase
4. auditory bullae convex
5. total length less than 60 mm
6. prominent sagittal crest
7. last molar not dumbbell shaped
8. ventral edge of dentary without notch at posterior end
9. 34 teeth (DF = 3/3, 1/1, 3/3, 1/2)Felidae-teeth 30 or less, rounded skull, short, blunt rostrum, upper molar small, long canines
Puma concolor (mountain lion)
1. 4 upper cheek teeth each side
2. robust skull
3. 30 teeth (3/3, 1/1, 3/2, 1/1)Lynx rufus (bobcat)
1. 3 upper cheek teeth each side
2. 28 teeth (3/3, 1/1, 2/2, 1/1)
ORDER ARTIODACTYLA
Cervidae-lacrimal separated from nasal by antorbital fossa, no permanent horn cores, incisors absent above
Cervus elaphus (wapiti)
1. upper canines present
2. double lacrimal orifice
3. selenodont cheek teeth
4. rostral fenestrations
5. lacrimal depression anterior to eye
6. nasals proportionately longer than premaxillaries
7. frontal region only moderately depressed
8. 34 teeth (0/3, 1/1, 3/3, 3/3)Odocoileus hemionus (mule deer)
1. deep lacrimal fossa
2. upper canines absent
3. in males, dichotomously branching antlers
4. 32 teeth (0/3, 0/1, 3/3, 3/3)Odocoileus virginianus (white-tailed deer)
1. shallow lacrimal fossa
2. upper canines absent
3. in males, antlers with one main beam and tines branching dorsally
4. 32 teeth (0/3, 0/1, 3/3, 3/3)Antilocapridae-lacrimal separated from nasal by antorbital fossa, permanent horn
cores in both sexes, erect and bladelike, incisors absent in upper jawAntilocapra americana (pronghorn)
1. deciduous horns with bony core persistant in both sexes
2. horn sheath with one branch (prong) in males and no branches in females
3. frontal foramina
4. depression between protruding orbits
5. 32 teeth (0/3, 0/1, 3/3, 3/3)Bovidae-one lacrimal foramen on or just within anterior orbital rim; heard ornamentation consisting of permanent bony cores surrounded by permanent horny sheaths
Bison bison (bison)
1. frontals expand laterally behind orbits
2. zygomata not visible from above
3. premaxillae not in contact with nasals
4. 32 teeth (0/3, 0/1, 3/3, 3/3)
INTRODUCED SPECIES
ORDER ARTIODACTYLA
Bovidae-one lacrimal foramen on or just within anterior orbital rim; heard ornamentation consisting of permanent bony cores surrounded by permanent horny sheaths
Bos taurus (cattle)
1. frontals not expanded laterally behind orbits
2. zygomatic arch visible from above
3. premaxillae in contact with nasals
4. 32 teeth (0/3, 0/1, 3/3, 3/3)
ORDER PERISSODACTYLA
Equidae-elongate, heavy skull with rectangular, high-crowned (hypsodont) molars
Equus caballus (horse)
1. canines not present in mares and geldings (present in stallions)
2. molars rectangular in shape
3. lower canines not crowded forward with incisors
4. P1 usually visible, but P1 rarely emerges from lower jaw
5. 36 teeth (3/3, 0/0, 3/3, 3/3)