Canids:
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, and jackals. The Canidae family is divided into the "true dogs" 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.
[edit] 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 of the Canids
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An approximate timescale of key events in canid evolution.
For precise dates, see text.
Axis scale: millions of years ago.
[edit] Evolution
[edit] 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 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.
[edit] 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. Hesperocyonines became extinct except for the Nothocyon and Leptocyon branches. These branches led to the borophagine and canine radiations.[6]
[edit] Miocene epoch
Around 9-10 Mya during the Late Miocene, Canis, Urocyon, and Vulpes genera expanded from southwestern North America. This was the point where the canine radiation began. The success of the these canines was related to the development of lower carnassials that were capable of both mastication and shearing. Around 8 Mya, Beringia offered the canines a way to enter Eurasia.
[edit] Pliocene epoch
[edit] Early Pliocene
During the Pliocene around (4-5 Mya) Canis lepophagus appeared in North America. This was small and sometimes coyote-like. Others were wolf-like in characteristics. It is theorized that Canis latrans (the coyote) descended from Canis lepophagus.[7] Around 1.5 to 1.8 Mya, a variety of wolves were present in Europe. Also, the North American wolf line appeared with Canis edwardii, clearly identifiable as a wolf. Canis rufus appeared, possibly a direct descendent of Canis edwardii.
[edit] Middle Pliocene
Around 0.8 Mya Canis ambrusteri, emerged in North America. A large wolf, it was found all over the continent. It is thought that this species migrated to South America where it became the ancestor of Canis dirus, the dire wolf.
[edit] Late Pliocene
At 0.3 Mya Canis lupus (the gray wolf) was fully developed and had spread throughout Europe and northern Asia. Berengia offered a way to North America.[8] At around 100,000 years ago, the dire wolf, one of the largest members of the dog family, had spread from South America to southern Canada and from coast to coast. The dire wolf shared its habitat with the gray wolf. Around 8000 years ago the dire wolf became extinct.
[edit] 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.
[edit] Dentition
Most canids have 42 teeth, with a dental formula of:
As in other members of 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.
[edit] Species and taxonomy
FAMILY CANIDAE
Subfamily: Caninae
- True dogs - Tribe Canini
- Genus Canis
- Side-striped Jackal, Canis adustus
- Golden Jackal, Canis aureus
- Coyote, Canis latrans (also called Prairie Wolf)
- Gray Wolf, Canis lupus (2.723 Ma to present)
- Red Wolf, Canis lupus rufus (3 Ma to present) (sometimes considered a separate species)
- Domestic Dog, Canis lupus familiaris
- Dingo, most often classified as Canis lupus dingo
- New Guinea Singing Dog, Canis lupus hallstromi
- Eastern Wolf, Canis (lupus) lycaon (sometimes considered a separate species)
- Indian Wolf, Canis indica (sometimes considered a separate species)
- Himalayan Wolf, Canis himalayensis (sometimes considered a separate species)
- many other proposed subspecies
- Black-backed Jackal, Canis mesomelas
- Ethiopian Wolf, Canis simensis (also called Abyssinian Wolf, Simien Fox and Simien Jackal)
- Genus Cynotherium †
- Genus Cuon
- Dhole, Cuon alpinus or Canis alpinus (also called Asian Wild Dog)
- Genus Lycaon
- Genus Indocyon†
- Genus Cubacyon
- Genus Atelocynus
- Genus Cerdocyon
- Genus Dasycyon † ?
- Genus Dusicyon †
- Genus Pseudalopex
- Genus Chrysocyon
- Genus Speothos
- True foxes - Tribe Vulpini
- Genus Vulpes
- Arctic Fox, Vulpes lagopus
- Red Fox, Vulpes vulpes (1 Ma to present)
- Swift Fox, Vulpes velox
- Kit Fox, Vulpes macrotis
- Corsac Fox, Vulpes corsac
- Cape Fox, Vulpes chama
- Pale Fox, Vulpes pallida
- Bengal Fox, Vulpes bengalensis
- Tibetan Sand Fox, Vulpes ferrilata
- Blanford's Fox, Vulpes cana
- Rüppell's Fox, Vulpes rueppelli
- Fennec Fox, Vulpes zerda
- Genus Urocyon (2 Ma to present)
- Basal Caninae
- Genus Otocyon (probably a vulpine close to Urocyon)
- Genus Nyctereutes
[edit] Fossil Canidae
Classification of Hesperocyoninae from Wang (1994)[10] and Borophaginae from Wang et al. (1999),[11] except where noted.
Prehistoric Caninae
- Canini
- Genus Canis
- Dire Wolf, Canis dirus (1 Ma †)
- Canis arnensis (3.4 Ma, †)
- Canis (Eucyon) cipio (8.2 Ma †, probably first species of Canis genus)
- Canis etruscus (3.4 Ma †)
- Canis mosbachensis (0.787 Ma †)
- Canis lepophagus (4-5 Ma †)
- Canis donnezani (4.0-3.1 Ma †, probably ancestor of wolves)
- Canis edwardii (1.8 Ma †, first species of wolf in North America)
- Canis gezi †
- Canis nehringi †
- Canis ameghinoi †
- Canis michauxi †
- Canis adoxus †
- Canis cautleyi †
- Canis armbrusteri (0.8 Ma †)
- Genus Theriodictis (1.8 Ma †)
- Theriodictis platensis (1.8 Ma †)
- Theriodictis tarijensis (1.8 Ma †)
- Theriodictis (Canis) proplatensis (2.1 Ma † )
- Genus Protocyon †
- Protocyon orcesi †
- Protocyon scagliarum †
- Protocyon troglodytes †
- Genus Dusicyon †
- Genus Cerdocyon
- Genus Speothos
- Genus Nurocyon
- Nurocyon chonokhariensis †
- Genus Xenocyon
- Vulpini
- Genus Vulpes (7 Ma to present)
- Vulpes alopecoides (2.6 Ma †)
- Vulpes cf. alopecoides (2.6 Ma †)
- Vulpes cf. vulpes (0.1275 Ma †)
- Vulpes galaticus (4.2 Ma †)
- Vulpes riffautae (7 Ma †)
- Basal Canids
- Genus Nyctereutes (7.1 Ma to present)
- Nyctereutes cf. donnezani (7.1 Ma †)
- Nyctereutes cf. megamastoides (3.158 Ma †)
- Nyctereutes donnezani (3.4 Ma †)
- Nyctereutes megamostoides (2.6 Ma †)
- Nyctereutes sinensis (3.4 Ma †)
- First Caninae
- Genus Eucyon (8 Ma †)
- Eucyon davisi (8.3 Ma †, probably ancestor of Canis)
- Eucyon minor (8 Ma †)
- Eucyon zhoui (8 Ma †)
- Eucyon monticinensis(8 Ma †)
- Eucyon odessanus †
- Genus Leptocyon (24-16 Ma †)
- Leptocyon vafer (16 Ma)
- Leptocyon vulpinus (24 Ma)
Borophaginae : † (Ma = million years ago)
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- Genus Aelurodon (16-12 Ma)
- Aelurodon asthenostylus (16 Ma)
- Aelurodon ferox (15 Ma)
- Aelurodon mcgrewi (15 Ma)
- Aelurodon montanensis (15 Ma)[12]
- Aelurodon stirtoni (13 Ma)
- Aelurodon taxoides (12 Ma)
- Genus Archaeocyon (32-24 Ma)
- Archaeocyon falkenbachi (25-24 Ma)
- Archaeocyon leptodus (32-24 Ma)
- Archaeocyon pavidus (32-28 Ma)
- Genus Borophagus (12-5 Ma)
- Borophagus dividersidens (5 Ma)
- Borophagus dudleyi
- Borophagus hilli (6 Ma)
- Borophagus littoralis (12 Ma)
- Borophagus orc (9 Ma)
- Borophagus parvus (7 Ma)
- Borophagus pugnator (9 Ma)
- Borophagus secundus (9 Ma)
- Genus Carpocyon
- Carpocyon compressus
- Carpocyon limosus
- Carpocyon robustus
- Carpocyon webbi
- Genus Cormocyon
- Cormocyon copei
- Cormocyon haydeni
- Genus Cynarctoides (30-18 Ma)
- Cynarctoides acridens (24 Ma)
- Cynarctoides emryi (21 Ma)
- Cynarctoides gawnae (18 Ma)
- Cynarctoides harlowi (21 Ma)
- Cynarctoides lemur (30 Ma)
- Cynarctoides luskensis (21 Ma)
- Cynarctoides roii (30 Ma)
- Genus Cynarctus (16-12 Ma)
- Cynarctus crucidens (12 Ma)
- Cynarctus galushai (16 Ma)
- ?Cynarctus marylandica
- Cynarctus saxatilis (15 Ma)
- Cynarctus voorhiesi (13 Ma)
- Genus Desmocyon (24-19 Ma)
- Desmocyon matthewi (19 Ma)
- Desmocyon thompsoni (24 Ma)
- Genus Epicyon (12-10 Ma)
- Epicyon aelurodontoides (10.3-4.9 Ma)
- Epicyon haydeni (10 Ma)
- Epicyon saevus (12 Ma)
- Genus Eulopocyon (18-16 Ma)
- Eulopocyon brachygnathus (16 Ma)
- Eulopocyon spissidens (18 Ma)
- Genus Metatomarctus (19-16 Ma)
- Metatomarctus canavus (19 Ma)
- Metatomarctus sp. A (16 Ma)
- Metatomarctus sp. B (16 Ma)
- Genus Microtomarctus (18 Ma)
- Microtomarctus conferta (18 Ma)
- Genus Otarocyon (34-30 Ma)
- Otarocyon cooki (30 Ma)
- Otarocyon macdonaldi (34 Ma)
- Genus Oxetocyon (32 Ma)
- Oxetocyon cuspidatus (32 Ma)
- Genus Paracynarctus (19-16 Ma)
- Paracynarctus kelloggi (19 Ma)
- Paracynarctus sinclairi (16 Ma)
- Genus Paratomarctus (16-13 Ma)
- Paratomarctus euthos (13 Ma)
- Paratomarctus temerarius (16 Ma)
- Genus Phlaocyon (30-19 Ma)
- Phlaocyon achoros
- Phlaocyon annectens (22 Ma)
- Phlaocyon latidens (30 Ma)
- Phlaocyon leucosteus (22 Ma)
- Phlaocyon mariae
- Phlaocyon marslandensis (19 Ma)
- Phlaocyon minor (30 Ma)
- Phlaocyon multicuspus
- Phlaocyon taylori[13]
- Phlaocyon yakolai (19 Ma)
- Genus Protepicyon (16 Ma)
- Genus Protomarctus (18 Ma)
- Protomarctus optatus (18 Ma)
- Genus Psalidocyon (16 Ma)
- Psalidocyon marianae (16 Ma)
- Genus Rhizocyon (30 Ma)
- Rhizocyon oregonensis (30 Ma)
- Genus Tephrocyon (16 Ma)
- Tephrocyon rurestris (16 Ma)
- Genus Tomarctus (16 Ma)
- Tomarctus brevirostris (16 Ma)
- Tomarctus hippophaga (16 Ma)
Hesperocyoninae : † (Ma = million years ago)
-
- Genus Cynodesmus (32-29 Ma)
- Cynodesmus martini (29 Ma)
- Cynodesmus thooides (32 Ma)
- ?Genus Caedocyon
- Genus Ectopocynus (32-19 Ma)
- Ectopocynus antiquus (32 Ma)
- Ectopocynus intermedius (29 Ma)
- Ectopocynus siplicidens (19 Ma)
- Genus Enhydrocyon (29-25 Ma)
- Enhydrocyon basilatus (25 Ma)
- Enhydrocyon crassidens (25 Ma)
- Enhydrocyon pahinsintewkpa (29 Ma)
- Enhydrocyon stenocephalus (29 Ma)
- Genus Hesperocyon (39.74-34 Ma)
- Hesperocyon coloradensis
- Hesperocyon gregarius (37 Ma)
- Genus Mesocyon (34-29 Ma)
- Mesocyon brachyops (29 Ma)
- Mesocyon coryphaeus (29 Ma)
- Mesocyn temnodon
- Genus Osbornodon (32-18 Ma)
- Osbornodon brachypus
- Osbornodon fricki (18 Ma)
- Osbornodon iamonensis (21 Ma)
- Osbornodon renjiei (33 Ma)
- Osbornodon scitulus[14]
- Osbornodon sesnoni (32 Ma)
- Osbornodon wangi[13]
- Genus Paraenhydrocyon (30-25 Ma)
- Paraenhydrocyon josephi (30 Ma)
- Paraenhydrocyon robustus (25 Ma)
- Paraenhydrocyon wallovianus (26 Ma)
- Genus Philotrox (29 Ma)
- Philotrox condoni (29 Ma)
- Genus Prohesperocyon (36 Ma)
- Prohesperocyon wilsoni (36 Ma)
- Genus Sunkahetanka (29 Ma)
- Sunkahetanka geringensis (29 Ma)
[edit] See also
[edit] References
- ^ a b 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.
- ^ 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 27 April 2008.
- ^ [1]
- ^ 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 28 November 2008.
- ^ Van Valkenburgh, B. (2004). "Cope's Rule, Hypercarnivory, and Extinction in North American Canids". Science 30: 101. doi:10.1126/science.1102417. edit
- ^ 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.
- ^ Nowak, R.M. 1979. North American Quaternary Canis. Monograph of the Museum of Natural History, University of Kansas 6:1 - 154.
- ^ Nowak, R. 1992. Wolves: The great travelers of evolution. International Wolf 2(4):3 - 7.
- ^ Macdonald, D. (1984). The Encyclopedia of Mammals. New York: Facts on File. pp. 57. ISBN 0-87196-871-1.
- ^ 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.
- ^ 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.
- ^ 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 8 July 2007.
- ^ a b 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.
- ^ 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.
[edit] 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
[edit] External links
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