Canidae

Canids[1]
Fossil range: 39.75–0 Ma
Late Eocene - Recent
Coyote (Canis latrans)
Coyote (Canis latrans)
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Suborder: Caniformia
Family: Canidae
G. Fischer de Waldheim, 1817
Genera and species

See text

Canidae (IPA: /ˈkænədiː/, ′kanə′dē) is the biological family of the dogs; a member of this family is called a canid. They include wolves, foxes, coyotes, jackals. The Canidae family is divided into the "true dogs" (or canines) of the tribe Canini and the "foxes" of the tribe Vulpini. The two species of the basal Caninae are more primitive and don't fit into either tribe. Any member of this family can be referred to generally as a canid.

Contents

Classification and relationship

Note that the subdivision of Canidae into "foxes" and "true dogs" may not be in accordance with the actual relations, and that the taxonomic classification of several canines is disputed. Recent DNA analysis has shown, however, that Canini (dogs) and Vulpini (foxes) are valid clades. (See phylogeny below). Molecular data implies a North American origin of living Canidae and an African origin of wolf-like canines (Canis, Cuon, and Lycaon).[2]

Currently the domestic dog is listed as a subspecies of Canis lupus, C. l. familiaris, with the Dingo (also considered a domestic dog) listed as C. l. dingo, provisionally a separate subspecies from C. l. familiaris; the Red Wolf, Eastern Canadian Wolf, and Indian Wolf are recognized as subspecies as well.[1]

The domestic dog is listed by many sources as Canis familiaris, but others, (including the Smithsonian Institution and the American Society of Mammalogists, more precisely list it as a subspecies of the Gray Wolf (i.e., Canis lupus familiaris); the Red Wolf, Eastern Canadian Wolf, and Indian Wolf may or may not be separate species; and the Dingo has been in the past variously classified as Canis dingo, Canis familiaris dingo and Canis lupus familiaris dingo.

Evolution

Eocene epoch

Carnivorans evolved from miacoids about 55 million years ago during the late Paleocene.[3] Then, about 50 million years ago, the carnivorans split into two main divisions: caniforms (dog-like) and feliforms (cat-like). By 40 million years ago the first clearly identifiable member of the dog family Canidae had arisen. It was called Prohesperocyon wilsoni and was found in an area what is now southwestern Texas. This fossil species bears a combination of features that definitively mark it as a canid: teeth that include the loss of the upper third molar (a general trend toward a more shearing bite), and the characteristically enlarged bony bulla (the rounded covering over the middle ear). Based on what we know about its descendants, Prohesperocyon likely had slightly more elongated limbs than its predecessors, along with toes that were parallel and closely touching, rather than splayed, as in bears.[4]

The Canidae family soon subdivided into three subfamilies, each of which diverged during the Eocene: Hesperocyoninae (~39.74-15 Mya), Borophaginae (~36-2 Mya), and the Caninae lineage that led to present-day canids (wolves, foxes, coyotes, jackals, and domestic dogs). Each of these groups showed an increase in body mass with time, and sometimes exhibited a specialised hypercarnivorous diet that made them prone to extinction.[5]:Fig. 1 Only the Caninae lineage, commonly referred to as "canines," survived to the present day.

Oligocene epoch

The earliest branch of the Canidae was the Hesperocyoninae lineage, which included the coyote-sized Mesocyon of the Oligocene (38-24 Mya). These early canids probably evolved for fast pursuit of prey in a grassland habitat, and resembled modern civets in appearance. Hesperocyonine dogs became extinct except for the Nothocyon and Leptocyon branches. These branches lead to the borophagine and canine radiations.[6]

Miocene epoch

Around 9-10 Mya during the Late Miocene, Canis, Urocyon, and Vulpes genera expand from southwestern North America. This is the point where canine radiation begins. The success of the these canines is the development of lower carnassials that are capable of both mastication and shearing. Around 8 Mya, Berengia offers the canines a way to enter Eurasia.

Pliocene epoch

Early Pliocene

During the Pliocene around (4-5 Mya) Canis lepophagus appears in North America. This dog is small with some being coyote-like. Others are wolf-like in characteristics. It is theorized that Canis latrans (coyote) descended from Canis lepophagus.[7] Around 1.5 to 1.8 Mya, a variety of wolves are now in Europe. Also, the North American wolf line appears with Canis edwardii as clearly identifiable as a wolf. Canis rufus, a red wolf canine appears and possibly a direct descendent of Canis edwardii.

Middle Pliocene

Around 0.8 Mya Canis ambrusteri, emerges in North America. A large wolf, it is found all over the continent. It is thought that this species went to South America where it becomes the ancestor of the Canis dirus or Dire wolf.

Late Pliocene

At 0.3 Mya Canis lupus (Gray wolf) has fully developed and has spread throughout Europe and northern Asia. Berengia offers a way to North America. [8] At around 100,000 years ago, the Dire wolf, some of the largest members of the dog family, appears from southern Canada to South America and coast to coast. The Dire wolf shares its habitat with the Gray wolf. Around 8000 years ago the Dire wolf becomes extinct.

Characteristics

Wild canids are found on every continent except Antarctica, and inhabit a wide range of different habitats, including deserts, mountains, forests, and grassland. They vary in size from the Fennec Fox at 24 cm in length, to the Gray Wolf, which may be up to 2 m long, and can weigh up to 80 kg.

With the sole living exception of the Bush Dog, canids have relatively long legs and lithe bodies, adapted for chasing prey. All canids are digitigrade, meaning that they walk on their toes. They possess bushy tails, non-retractile claws, and a dewclaw on the front feet. They possess a baculum, which together with a cavernous body helps to create a copulatory tie during mating, locking the animals together for up to an hour. Young canids are born blind, with their eyes opening a few weeks after birth. [9]

Many species live and hunt in packs, and have complex social lives. They are generally highly adaptable, and there may be considerable variation in habits even within a single species.

Dentition

Most canids have 42 teeth, with a dental formula of:

3.1.4.2
3.1.4.3

As in other members of the carnivora, the upper fourth premolar and lower first molar are adapted as carnassial teeth for slicing flesh. The molar teeth are strong in most species, allowing the animals to crack open bone to reach the marrow. The deciduous or baby teeth formula in canids is 3 1 3; molars are completely absent.

Species and taxonomy

Gray Wolf
Coyote
African Hunting Dog
Red Fox
Red Wolf
Dhole
Golden Jackal
Bat-eared Fox
Gray Fox
Maned Wolf
Short-eared Dog
Pampas Fox
Arctic Fox
Raccoon Dog

FAMILY CANIDAE

Subfamily: Caninae

Fossil Canidae

Classification of Hesperocyoninae from Wang (1994)[10] and Borophaginae from Wang et al. (1999),[11] except where noted.

Prehistoric Caninae

Borophaginae : † (Ma = million years ago)

Hesperocyoninae : † (Ma = million years ago)

See also

References

  1. ↑ 1.0 1.1 Wozencraft, W. C. (16 November 2005). Wilson, D. E., and Reeder, D. M. (eds). ed.. Mammal Species of the World (3rd edition ed.). Johns Hopkins University Press. ISBN 0-801-88221-4. http://www.bucknell.edu/msw3/browse.asp?id=14000691. 
  2. ↑ Lindblad-toh, K.; Wade, C.M.; Mikkelsen, T.S.; Karlsson, E.K.; Jaffe, D.B.; Kamal, M.; Clamp, M.; Chang, J.L.; Kulbokas Iii, E.J.; Zody, M.C.; Others, (2005). "Genome sequence, comparative analysis and haplotype structure of the domestic dog". Nature 438 (7069): 803–819. doi:10.1038/nature04338. http://ccr.cancer.gov/resources/cop/nature04338.pdf. Retrieved on 2008-04-27. 
  3. ↑ [1]
  4. ↑ Wang, Xiaoming; Richard H. Tedford (2008). "How Dogs Came to Run the World". Natural History Magazine July/August. http://www.naturalhistorymag.com/master.html?http://www.naturalhistorymag.com/0708/0708_feature.html. Retrieved on 2008-11-28. 
  5. ↑ doi:10.1126/science.1102417
    Incomplete citation. Click here to automatically expand (or here to expand by hand)
  6. ↑ Martin, L.D. 1989. Fossil history of the terrestrial carnivora. Pages 536 - 568 in J.L. Gittleman, editor. Carnivore Behavior, Ecology, and Evolution, Vol. 1. Comstock Publishing Associates: Ithaca.
  7. ↑ Nowak, R.M. 1979. North American Quaternary Canis. Monograph of the Museum of Natural History, University of Kansas 6:1 - 154.
  8. ↑ Nowak, R. 1992. Wolves: The great travelers of evolution. International Wolf 2(4):3 - 7.
  9. ↑ Macdonald, D. (1984). The Encyclopedia of Mammals. New York: Facts on File. pp. 57. ISBN 0-87196-871-1. 
  10. ↑ Wang, Xiaoming (1994). "Phylogenetic systematics of the Hesperocyoninae". Bulletin of the American Museum of Natural History 221: 1–207. http://hdl.handle.net/2246/829. 
  11. ↑ Wang, Xiaoming; Richard Tedford, Beryl Taylor (1999). "Phylogenetic systematics of the Borophaginae". Bulletin of the American Museum of Natural History 243: 1–391. doi:10.1671/2493. http://hdl.handle.net/2246/1588. 
  12. ↑ Wang, Xiaoming; Wideman, Benjamin, Nichols, Ralph, & Hanneman, Debra (2004). "A new species of Aelurodon (Carnivora, Canidae) from the Barstovian of Montana". Journal of Vertebrate Paleontology 24 (2): 445–452. doi:10.1671/2493. http://www.nhm.org/expeditions/rrc/wang/documents/Wangetal2004MontanaAelurodon.pdf. Retrieved on 2007-07-08. 
  13. ↑ 13.0 13.1 Hayes, F.G. (2000). "The Brooksville 2 local fauna (Arikareean, latest Oligocene) Hernando County, Florida". Bulletin of the Florida Museum of Natural History 43 (1): 1–47. 
  14. ↑ Wang, Xiaoming (2003). "New Material of Osbornodon from the Early Hemingfordian of Nebraska and Florida". Bulletin of the American Museum of Natural History 279: 163–176. http://digitallibrary.amnh.org/dspace/bitstream/2246/447/19/B279a08.pdf. 

General references

Xiaoming Wang, Richard H. Tedford, Mauricio Antón, Dogs: Their Fossil Relatives and Evolutionary History, New York : Columbia University Press, 2008; ISBN 978-0-231-13528-3

External links

Extant Carnivora families by suborder
Kingdom Animalia · Phylum Chordata · Class Mammalia · Infraclass Eutheria · Superorder Laurasiatheria
Feliformia
Nandiniidae · Felidae · Viverridae · Hyaenidae · Eupleridae · Herpestidae
Caniformia
Canidae · Ursidae · Ailuridae · Mephitidae · Mustelidae · Procyonidae · Odobenidae · Otariidae · Phocidae