Lab 15-Order CARNIVORA

(dogs, cats, hyaenas, genets, mongoose, bears, raccoon, weasels, seals, sea lions, walrus)

The classification of carnivores remains a subject of considerable debate. Simpson’s 1945 classification separated the seals, sea lions, and walrus as a separate Order Pinnipedia (“wing [=finned] foot”), based primarily on the extreme modifications of the skeleton and teeth for aquatic locomotion and feeding, with the Order Carnivora encompassing the fissiped (“split [=toed] foot”) families (dogs, cats, hyaenas, and so forth). Phylogenetic analyses of both morphological and molecular characters, however, clearly indicate that, while the pinnipeds form a monophyletic lineage, this lineage is nested within the fissiped carnivores. It is still argued if the pinnipeds, however, are more closely related to mustelids or to bears.

Carnivores are divided into two groups, although the names of these differ among authors. Older classifications place the cats, hyaenas, genets, and mongooses in the superfamily Aeluroidea and the dogs, bears, weasels, and procyonids in the superfamily Arctoidea. Current classifications, however, use the terms Feliformia for the cat lineage and Caniformia for the dog lineage, restricting the term Arctoidea to a clade comprised of the bears, weasels, raccoons, and pinnipeds and the sister clade to the dogs (Canoidea).

One phylogeny reflecting this recent classification is:

Characters that can distinguish carnivores from other mammals include the following:

fissiped carnivores:

1. canines large, pointed, curved

2. cheekteeth secodont or bunodont, carnassial pair (PM4/m1) present (weakly developed in bears and most procyonids); molars usually with crushing surfaces (except lower first molar in most)

3. incisors 3/3 (3/2 in sea otter, Enhydra [Mustelidae]))

4. limbs variable in length but always with claws

5. feet either plantigrade or digitigrade

6. pinna prominent

7. eyes variable in position, usually well separated

8. post-orbital processes on frontal and zygomatic arch usually present

9. lacrimal foramen present

pinniped carnivores:

1. canines large (upper canine enormous in walrus), pointed, curved

2. cheekteeth relatively simple, conical or with secondary cusps anterior and posterior to main cusp, without crushing surfaces; no carnassial slicing pair

3. incisors 1-3/0-2

4. forelimbs and hind limbs modified into flippers

5. body streamlined, torpedo-shaped; hair very short

6. pinna reduced or absent

7. eyes positioned forward on face, close together

8. post-orbital process present only in sea lions

9. no lacrimal foramen

Family CANIDAE (dogs, wolves, coyotes, foxes)

general characters: 1. size medium (55-200 cm) 2. tail long, bushy 3. foot posture digitigrade forefoot hind foot 4. digits 5-4 or 4-4 5. claws well developed, relatively straight, non-retractile 6. skull elongate; rostrum relatively long, narrow 7. mastoid process smaller than paroccipital process 8. alisphenoid canal present 9. diagonal division between ectotympanic and entotympanic, with entotympanic slightly larger 10. carnassials well developed 11. last upper molar relatively large, transversely elongate 12. well developed talonid on first lower molar

upper and lower cheekteeth of a coyote, Canis

dental formula:

usually

3 1 4 2 3 1 4 3

= 42

upper molars may range from 1-4 and lower molars from 2-5

genera: 14 genera, including Alopex (Arctic fox), Atelocynus (short-eared bushdog of South American tropical forests), Canis (dog, dingo, coyote, jackal, wolf), Chrysocyon (maned wolf of South America), Cuon (dhole), Dusicyon (South American fox), Lycaon (African wild dog), Nyctereutes (raccoon dog), Otocyon (African bat-eared fox), Speothos (bush dog of South America), Urocyon (gray fox), and Vulpes (foxes)

range: cosmopolitan, except Madagascar, New Zealand, Philippine Islands

Family URSIDAE (bears)

general characters: 1. size large (110-260 cm) 2. tail short 3. foot posture plantigrade forefoot hind foot 4. digits 5-5 5. claws large, curved, non-retractile 6. skull elongate; rostrum relatively long, narrow 7. mastoid process subequal in size to paroccipital process 8. alisphenoid canal present 9. division between ectotympanic and entotympanic both horizontal and vertical; ectotympanic very large 10. carnassials poorly developed; molars with flat, broad crowns 11. last upper molar very large, elongate anteroposteriorly

cheekteeth of a bear, Ursus

dental formula:

3 1 4 2 3 1 4 3

= 42

genera: 6 genera, including Ailuropoda (giant panda), Helarctos (sun bear), Melursus (sloth bear), Selenarctos (Asian black bear), Tremarctos (spectacled bear), Ursus (brown and black bears)

note: (1) many earlier classifications placed the giant panda (Ailuropoda), along with the lesser panda (Ailurus) in the raccoon family, Procyonidae. The placement of the giant panda with the bears, however, is no longer in dispute, as it is supported by a large number of morphological characters and by all molecular analyses that have been done. (2) The polar bear is sometimes placed in its own genus (Thalarctos), but phylogenetic analyses of both morphology and molecules indicates that the polar bear is the sister to the brown bears and that its lineage is phylogenetically nested within the genus Ursus.

range: North American, Eurasia, Southeast Asia, India, Andes of South America. Absent from rest of South America, Africa, southwestern Asia, and Australia.

Family PROCYONIDAE (coati, kinkajou, olingo, ring-tailed cat, raccoon)

general characters:

1. size medium (60-135 cm)

2. tail long, usually ringed with alternating black- and light-colored bands

3. foot posture plantigrade, or semi-plantigrade

forefoot hind foot

4. digits 5-5

5. claws prominent, non-retractile

6. skull robust, usually elongate, rostrum not particularly narrow

7. mastoid process equal to or larger in size than paroccipital process

8. no alisphenoid canal (except in Ailurus)

9. horizontal and vertical division between enlarged ectotympanic and small entotympanic

10. carnassials poorly developed (except Bassariscus), upper molars usually with hypocone

11. last upper molar relatively large, rounded

upper right PM4 and M1 of a raccoon lower left m1 and m2 of a raccoon

dental formula:

3 1 3-4 2 3 1 3-4 2

= 36-40

genera: 7 genera, including Bassaricyon (olingo), Potos (kinkajou), Bassariscus (ring-tailed cat), Nasua (coati, coatimundi), Nasuella (coati), Procyon (raccoon), Ailurus (lesser panda)

range: the family is restricted to the temperate and tropical regions of North and South America, except for the lesser panda which is found in southern China.

Family MUSTELIDAE (weasels, stoats, ferrets, skunks, otters, badgers, martens, fisher, wolverine)

general characters:

1. postmandibular process often prominent and curved around mandibular fossa, often locking lower jaw into place

2. size small to medium (15-155 cm)

3. tail variable, but usually long

4. foot posture plantigrade (badgers, skunks) to digitigrade (weasels); partially webbed in otters

skunk (Conepatus)

forefoot hind foot

weasel (Mustela)

forefoot hind foot

otter (Lontra)

5. digits 5-5

6. claws well developed, semi-retractile

7. skull blocky, robust, often flattened; rostrum short

8. mastoid process absent or smaller than paroccipital process

9. no alisphenoid canal

10. both horizontal and vertical division between enlarged ectotympanic and small entotympanic

11. carnassials usually well developed

12. upper molar relatively large, usually dumbbell-shaped or squarish

upper and lower cheekteeth of a weasel, Mustela

upper and lower teeth of the sea otter, Enhydra

dental formula:

usually

3 1 3 1 3 1 3 2

= 34

3 1 2-4 1 2-3 1 2-4 1-2

= 30-38

May be as variable as:

genera: mustelids are traditionally divided into six subfamilies, as follows:

Lutrinae (otters): 7 genera, including Amblonyx (small-clawed otter), Enhydra (sea otter), Lontra (New World otters), Lutra (Old World otters), Pteronura (giant otter)

Melinae (Old World badgers): 4 genera, including Arctonyx (hog badger), Meles (Eurasian badger), Melogale (ferret badger)

Mellivorinae (honey badgers): 1genus, Mellivora

Mephitinae (skunks): 3 genera, including Conepatus (hog-nosed skunks), Mephitis (striped and hooded skunks), Spilogale (spotted skunks)

Mustelinae (weasels and relatives): 9 genera, including Eira (tyra), Galictis (grison), Gulo (wolverine), Ictonyx (zorilla), Lyncodon (Patagonian grison), Martes (marten, fisher), Mustela (weasels, ferrets, stoats, polecats, mink), Vormela (marbled polecat)

Taxidiinae (American badger): 1 genus, Taxidea

note: recent molecular studies suggest that the skunks should belong to a family unto themselves, the Mephitidae

range: all continents, except Australia and Antarctica; absent from islands of New Guinea, New Zealand, and Madagascar

Family OTARIIDAE (sea lions, fur seals, stellar sea lion)

general characters:

1. body large

2. pinna present (absent in other pinnipeds)

3. supraorbital process well developed (absent or rudimentary in other pinnipeds)

4. body relatively uniform in color, never spotted

5. hind limbs capable of being turned forward

6. nails prominent on middle three digits of hindfoot; skin of flipper extending distally beyond nails

7. testes scrotal

8. alisphenoid canal present

9. mastoid process separate from auditory bulla

10. medial two upper incisors with transverse groove

11. cheekteeth simple, usually with only one large cusp

dental formula:

3 1 4 1-3 2 1 4 1

= 34-38

genera: 7 genera, including Arctocephalus (southern fur seals), Callorhinus (northern fur seals), Eumetopias (Stellar sea lion), Neophoca (Australian sea lion), Otaria (southern seal lion), Phocarctos (New Zealand sea lion), Zalophus (California sea lion)

usually divided into two subfamilies, the Arctocephalinae (fur seals), and Otariinae (sea lions)

range: coasts of northeastern Asia, western North America, South America, southern Africa, southern Australia, New Zealand, and most predominantly southern oceanic islands

Family PHOCIDAE (true, earless, or hair seals)

general characters: 1. body usually spotted or banded (uniformly colored in elephant seals) 2. hind limbs extended posteriorly, incapable of forward rotation 3. claws present on digits of forefoot and usually on hindfoot; skin on flipper not extending beyond nails 4. testes abdominal 5. no alisphenoid canal 6. mastoid process bound to auditory bulla, the latter inflated 7. upper incisors not grooved 8. cheekteeth usually multi-cusped cheekteeth of crab-eater seal, Lobodon

dental formula:

2-3 1 4 0-2 1-2 1 4 0-2

= 26-36

genera: 10 genera, including Cystophora (hooded seal), Erignathus (bearded seal), Halichoerus (gray seal), Hydruga (leopard seal), Leptonychotes (Weddell seal), Lobodon (crab-eater seal), Mirounga (elephant seals), Monachus (monk seal), Ommatophoca (Ross seal), Phoca (harbor, ringed, harp, and ribbon seals)

range: ice fronts and coastlines of polar and temperate parts of the oceans and adjoining seas of the world, but extending to some tropical island areas

Family ODOBENIDAE (walrus)

general characters: 1. body very large, uniform in color, never spotted 2. hind limbs capable of being turned forward 3. nails present on all digits of forefoot and hindfoot; skin of flipper not extending distally beyond nails 4. testes abdominal 5. upper canine enormous, tusk-like 6. upper incisors small, conical 7. no lower incisors 8. alisphenoid canal present 9. mastoid process enormous, bound to auditory bulla 10. cheekteeth simple, peg-like