Canis

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Canis
Temporal range: 6–0  Ma
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Canis.jpg
Gray wolf (top), coyote and African golden wolf (top middle), Ethiopian wolf and Eurasian golden jackal (bottom middle), black-backed jackal and side-striped jackal (bottom)
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Canidae
Subfamily: Caninae
Tribe: Canini
Genus: Canis
Linnaeus, 1758 [1]
Extant species

 1C. lupus also includes domestic dogs, C. l. familiaris, and dingoes, C. l. dingo

Contents

Canis is a genus of the Canidae containing multiple extant species, such as wolves, dogs, coyotes and jackals. Species of this genus are distinguished by their moderate to large size, their massive, well-developed skulls and dentition, long legs, and comparatively short ears and tails. [2]

Etymology

The generic name Canis means "dog" in Latin. The term "canine" comes from the adjective form, caninus ("of the dog"), from which the term canine tooth is also derived. [3] The canine family has prominent canine teeth, used for killing their prey. The word canis is cognate to the Greek word kūon (Greek: Κύων), which means "dog", as well as (less transparently) English hound.

Terminology

Taxonomy

Canini

The tribe Canini [6] (Fischer de Waldheim, 1817) is the sister group to the true foxes ( Vulpes ), and is represented today by two sub-tribes: Canina, which includes the genus Canis [7] (wolves, jackals, the coyote, and the domestic dog), as well as the dhole and the African wild dog; and Cerdocyonina, [8] which includes the so-called foxes of South America. [9] :p55 The critical features that mark the Canini as a monophyletic group include: the consistent enlargement of the frontal sinus, often accompanied by the correlated loss of the depression in the dorsal surface of the postorbital process; the posterior expansion of the paroccipital process; the enlargement of the mastoid process; and the lack of lateral flare of the orbital border of the zygoma. [9] :p77

Canis

While the tribe Canini (above) is monophyletic, the genus Canis is not. The genus Canis (Carl Linnaeus, 1758) was published in the 10th edition of Systema Naturae [1] and included the dog-like carnivores: the domestic dog, wolves, coyotes and jackals. All species within Canis are phylogenetically closely related with 78 chromosomes and can potentially interbreed. [10] In 1926, the International Commission on Zoological Nomenclature (ICZN) in Opinion 91 included Genus Canis on its Official Lists and Indexes of Names in Zoology. [11] In 1955, the ICZN's Direction 22 added Canis familiaris as the type specimen for genus Canis to the official list. [12]

Evolution

The fossil record shows that feliforms and caniforms emerged within the clade Carnivoramorpha 43 million YBP. [13] The caniforms included the fox-like genus Leptocyon whose various species existed from 24 million YBP before branching 11.9 million YBP into Vulpes (foxes) and Canini (canines). The jackal-sized Eucyon existed in North America from 10 million YBP and by the Early Pliocene about 6-5 million YBP the coyote-like Eucyon davisi [14] invaded Eurasia. In North America it gave rise to early Canis which first appeared in the Miocene (6 million YBP) in south-western USA and Mexico. By 5 million YBP the larger Canis lepophagus appeared in the same region. [15] :p58

Skulls of dire wolf (C. dirus), gray wolf (C. lupus), eastern wolf (C. lycaon), red wolf (C. rufus), coyote (C. latrans), African golden wolf (C. anthus), golden jackal (C. aureus) and black-backed jackal (C. mesomelas) C. dirus, C. lupus, C. lycaon, C. rufus, C. latrans, C. anthus C. aureus & C. mesomelas skulls.jpg
Skulls of dire wolf (C. dirus), gray wolf (C. lupus), eastern wolf (C. lycaon), red wolf (C. rufus), coyote (C. latrans), African golden wolf (C. anthus), golden jackal (C. aureus) and black-backed jackal (C. mesomelas)

The canids that had emigrated from North America to Eurasia – Eucyon , Vulpes , and Nyctereutes – were small to medium-sized predators during the Late Miocene and Early Pliocene but they were not the top predators. The position of the canids would change with the arrival of Canis to become a dominant predator across the Holarctic. The wolf-sized C. chihliensis appeared in northern China in the Mid-Pliocene around 4-3 million YBP. This was followed by an explosion of Canis evolution across Eurasia in the Early Pleistocene around 1.8 million YBP in what is commonly referred to as the wolf event. It is associated with the formation of the mammoth steppe and continental glaciation. Canis spread to Europe in the forms of C. arnensis , C. etruscus , and C. falconeri . [15] :p148 One study found that the diversity of the Canis group decreased by the end of the Early Pleistocene to the Middle Pleistocene and was limited in Eurasia to the small wolves of the Canis mosbachensis–Canis variabilis group and the large hypercarnivorous Canis (Xenocyon) lycaonoides. [16]

See further: Evolution of the canids

Dentition and biteforce

Diagram of a wolf skull with key features labelled Wolf cranium labelled.jpg
Diagram of a wolf skull with key features labelled
Eurasian wolf skull Lupocranio.jpg
Eurasian wolf skull
Bite force adjusted for body weight in Newtons per kilogram [17]
Canid Carnassial Canine
Wolf131.6127.3
Dhole 130.7132.0
African wild dog 127.7131.1
Greenland dog and Dingo 117.4114.3
Coyote 107.298.9
Side-striped jackal 93.087.5
Golden jackal 89.687.7
Black-backed jackal 80.678.3

Dentition relates to the arrangement of teeth in the mouth, with the dental notation for the upper-jaw teeth using the upper-case letters I to denote incisors, C for canines, P for premolars, and M for molars, and the lower-case letters i, c, p and m to denote the mandible teeth. Teeth are numbered using one side of the mouth and from the front of the mouth to the back. In carnivores, the upper premolar P4 and the lower molar m1 form the carnassials that are used together in a scissor-like action to shear the muscle and tendon of prey. [15] :74

Canids use their premolars for cutting and crushing except for the upper fourth premolar P4 (the upper carnassial) that is only used for cutting. They use their molars for grinding except for the lower first molar m1 (the lower carnassial) that has evolved for both cutting and grinding depending on the candid's dietary adaptation. On the lower carnassial the trigonid is used for slicing and the talonid is used for grinding. The ratio between the trigonid and the talonid indicates a carnivore's dietary habits, with a larger trigonid indicating a hypercarnivore and a larger talonid indicating a more omnivorous diet. [18] [19] Because of its low variability, the length of the lower carnassial is used to provide an estimate of a carnivore's body size. [18]

A study of the estimated bite force at the canine teeth of a large sample of living and fossil mammalian predators, when adjusted for their body mass, found that for placental mammals the bite force at the canines (in Newtons/kilogram of body weight) was greatest in the extinct dire wolf (163), followed among the modern canids by the four hypercarnivores that often prey on animals larger than themselves: the African hunting dog (142), the gray wolf (136), the dhole (112), and the dingo (108). The bite force at the carnassials showed a similar trend to the canines. A predator's largest prey size is strongly influenced by its biomechanical limits. [20]

Behavior

Description and sexual dimorphism

There is little variance among male and female canids. Canids tend to live as monogamous pairs. Wolves, dholes, coyotes, and jackals live in groups that include breeding pairs and their offspring. Wolves may live in extended family groups. To take prey larger than themselves, the African wild dog, the dhole, and the gray wolf depend on their jaws as they cannot use their forelimbs to grapple with prey. They work together as a pack consisting of an alpha pair and their offspring from the current and previous years. [21] Social mammal predators prey on herbivores with a body mass similar to that of the combined mass of the predator pack. [22] [23] The gray wolf specializes in preying on the vulnerable individuals of large prey, [24] and a pack of timber wolves can bring down a 500 kg (1,100 lb) moose. [25] [26]

Mating behaviour

The genus Canis contains many different species and has a wide range of different mating systems that varies depending on the type of canine and the species. [27] In a study done in 2017 it was found that in some species of canids females use their sexual status to gain food resources. The study looked at wolves and dogs. Wolves are typically monogamous and form pair-bonds; whereas dogs are promiscuous when free-range and mate with multiple individuals. The study found that in both species females tried to gain access to food more and were more successful in monopolize a food resource when in heat. Outside of the breeding season their efforts were not as persistent or successful. This shows that the food-for-sex hypothesis likely plays a role in the food sharing among canids and acts as a direct benefit for the females. [27]

Another study on free-ranging dogs found that social factors played a significant role in the determination of mating pairs. The study, done in 2014, looked at social regulation of reproduction in the dogs. [28] They found that females in heat searched out dominant males and were more likely to mate with a dominant male who appeared to be a quality leader. The females were more likely to reject submissive males. Furthermore, cases of male-male competition were more aggressive in the presence of high ranking females. This suggests that females prefer dominant males and males prefer high ranking females meaning social cues and status play a large role in the determination of mating pairs in dogs. [28]

Canids also show a wide range of parental care and in 2018 a study showed that sexual conflict plays a role in the determination of intersexual parental investment. [29] The studied looked at coyote mating pairs and found that paternal investment was increased to match or near match the maternal investment. The amount of parental care provided by the fathers also was shown to fluctuated depending on the level of care provided by the mother.

Another study on parental investment showed that in free-ranging dogs, mothers modify their energy and time investment into their pups as they age. [30] Due to the high mortality of free-range dogs at a young age a mother's fitness can be drastically reduced. This study found that as the pups aged the mother shifted from high-energy care to lower-energy care so that they can care for their offspring for a longer duration for a reduced energy requirement. By doing this the mothers increasing the likelihood of their pups surviving infancy and reaching adulthood and thereby increase their own fitness.

A study done in 2017 found that aggression between male and female gray wolves varied and changed with age. [31] Males were more likely to chase away rival packs and lone individuals than females and became increasingly aggressive with age. Alternatively, females were found to be less aggressive and constant in their level of aggression throughout their life. This requires further research but suggests that intersexual aggression levels in gray wolves relates to their mating system.

Tooth breakage

Dentition of a wolf showing functions of the teeth. Wolf dentition in the Ice Age.jpg
Dentition of a wolf showing functions of the teeth.

Tooth breakage is a frequent result of carnivores' feeding behaviour. [32] Carnivores include both pack hunters and solitary hunters. The solitary hunter depends on a powerful bite at the canine teeth to subdue their prey, and thus exhibits a strong mandibular symphysis. In contrast, a pack hunter, which delivers many shallower bites, has a comparably weaker mandibular symphysis. Thus, researchers can use the strength of the mandibular symphysis in fossil carnivore specimens to determine what kind of hunter it was a pack hunter or a solitary hunter and even how it consumed its prey. The mandibles of canids are buttressed behind the carnassial teeth to crack bones with their post-carnassial teeth (molars M2 and M3). A study found that the modern gray wolf and the red wolf (C. rufus) possess greater buttressing than all other extant canids and the extinct dire wolf. This indicates that these are both better adapted for cracking bone than other canids. [33]

A study of nine modern carnivores indicate that one in four adults had suffered tooth breakage and that half of these breakages were of the canine teeth. The highest frequency of breakage occurred in the spotted hyena, which is known to consume all of its prey including the bone. The least breakage occurred in the African wild dog. The gray wolf ranked between these two. [32] [34] The eating of bone increases the risk of accidental fracture due to the relatively high, unpredictable stresses that it creates. The most commonly broken teeth are the canines, followed by the premolars, carnassial molars, and incisors. Canines are the teeth most likely to break because of their shape and function, which subjects them to bending stresses that are unpredictable in direction and magnitude. [34] The risk of tooth fracture is also higher when taking and consuming large prey. [34] [35]

In comparison to extant gray wolves, the extinct Beringian wolves included many more individuals with moderately to heavily worn teeth and with a significantly greater number of broken teeth. The frequencies of fracture ranged from a minimum of 2% found in the Northern Rocky Mountain wolf (Canis lupus irremotus) up to a maximum of 11% found in Beringian wolves. The distribution of fractures across the tooth row also differs, with Beringian wolves having much higher frequencies of fracture for incisors, carnassials, and molars. A similar pattern was observed in spotted hyenas, suggesting that increased incisor and carnassial fracture reflects habitual bone consumption because bones are gnawed with the incisors and then cracked with the carnassials and molars. [36]

Wolves, dogs, and dingoes

Phylogenetic tree of the extant wolf-like canids with timing in millions of years [lower-alpha 1]
Caninae  3.5  Ma
3.0
2.5
2.0
0.96
0.60
0.38
0.25
?
0.08
0.031

Dog Tibetan mastiff (transparent background).png

Holarctic grey wolf Dogs, jackals, wolves, and foxes (Plate I).png

Late Pleistocene wolf The American Museum journal (c1900-(1918)) (Canis dirus) transparent background.png

Indian plains wolf Dogs, jackals, wolves, and foxes (Plate I).png

Himalayan wolf/Tibetan wolf Dogs, jackals, wolves, and foxes (Plate I).png

Coyote Dogs, jackals, wolves, and foxes (Plate IX).jpg

0.11

African golden wolf northwestern Africa Dogs, jackals, wolves, and foxes (Plate XI).jpg

African golden wolf eastern Africa Dogs, jackals, wolves, and foxes (Plate XI).jpg

Golden jackal Dogs, jackals, wolves, and foxes (Plate X).jpg

Ethiopian wolf Dogs, jackals, wolves, and foxes (Plate VI).jpg

Dhole Dogs, jackals, wolves, and foxes (Plate XLI).jpg

African wild dog Dogs, jackals, wolves, and foxes (Plate XLIV).jpg

2.6

Side-striped jackal Dogs, jackals, wolves, and foxes (Plate XIII).jpg

Black-backed jackal Dogs, jackals, wolves, and foxes (Plate XII).jpg

Blue shading represents the species Canis lupus

Wolves, dogs, and dingoes are subspecies of Canis lupus. The original referent of the English word wolf, the Eurasian wolf, is called C. l. lupus to distinguish it from other wolf subspecies, such as the Indian wolf (C. l. pallipes), the Arabian wolf (C. l. arabs), or the Tibetan wolf (C. l. filchneri).

Some experts have suggested some subspecies of C. lupus be considered Canis species distinct from C. lupus. These include Central Asia's Himalayan wolf, and the Indian wolf, [37] [38] as well as North America's red wolf and eastern wolf. [39]

The dingo (C. l. dingo), from Australasia, and the domestic dog (C. l. familiaris) are also considered subspecies of C. lupus, although they are not commonly referred to or thought of as "wolves". [40]

Coyotes, jackals, and wolves

The gray wolf (C. lupus), the Ethiopian wolf (C. simensis), and the African golden wolf (C. anthus) are three of the many Canis species referred to as "wolves"; however, all of the others are now extinct and little is known about them by the general public. One of these, the extinct dire wolf (C. dirus), has gained fame from the thousands of specimens found and displayed at the Rancho La Brea Tar Pits in Los Angeles, California.

Canis species that are too small to attract the word "wolf" are called coyotes in the Americas and jackals elsewhere. Although these may not be more closely related to each other than they are to C. lupus, they are, as fellow Canis species, all more closely related to wolves and domestic dogs than they are to foxes, maned wolves, or other canids which do not belong to the genus Canis. The word "jackal" is applied to three distinct species of this group: the side-striped (C. adustus) and black-backed (C. mesomelas) jackals, found in sub-Saharan Africa, and the Eurasian golden jackal (C. aureus), found across southwestern and south-central Asia, and the Balkans.

While North America has only one small-sized species, the coyote (C. latrans), it has become very widespread, moving into areas once occupied by wolves. They can be found across much of mainland Canada, in every state of the contiguous United States, all of Mexico except the Yucatán Peninsula, and the Pacific and central areas of Central America, ranging as far as western Panama.

African migration

The first record of genus Canis on the African continent is Canis sp. A from South Turkwel, Kenya dated 3.58–3.2 million years ago. [41] In 2015, a study of mitochondrial genome sequences and whole genome nuclear sequences of African and Eurasian canids indicated that extant wolf-like canids have colonised Africa from Eurasia at least 5 times throughout the Pliocene and Pleistocene, which is consistent with fossil evidence suggesting that much of African canid fauna diversity resulted from the immigration of Eurasian ancestors, likely coincident with Plio-Pleistocene climatic oscillations between arid and humid conditions. [42] :S1 In 2017, the fossil remains of a new Canis species named Canis othmanii was discovered among remains found at Wadi Sarrat, Tunisia from deposits that date 700,000 years ago. This canine shows a morphology more closely associated with canids from Eurasia rather than Africa. [43]

See also

Notes

  1. For a full set of supporting references refer to the note (a) in the phylotree at Evolution of the wolf#Wolf-like canids

Related Research Articles

Canidae family of mammals

Canidae is a biological family of dog-like carnivorans. A member of this family is called a canid. There are three subfamilies found within the canid family, which are the extinct Borophaginae and Hesperocyoninae, and the extant Caninae. The Caninae are known as canines, which includes domestic dogs, wolves, foxes and other extant and extinct species.

Jackal Several species of the wolf genus of mammals

Jackals are medium-sized omnivorous mammals of the genus Canis, which also includes wolves and the domestic dog. While the word "jackal" has historically been used for many small canids, in modern use it most commonly refers to three species: the closely related black-backed jackal and side-striped jackal of sub-Saharan Africa, and the golden jackal of south-central Eurasia, which is more closely related to other members of the genus Canis.

Dire wolf Extinct species of the genus Canis from North America

The dire wolf is an extinct species of the genus Canis. It is one of the most famous prehistoric carnivores in North America, along with its extinct competitor, the sabre-toothed cat Smilodon fatalis. The dire wolf lived in the Americas during the Late Pleistocene and Early Holocene epochs. The species was named in 1858, four years after the first specimen had been found. Two subspecies are recognized: Canis dirus guildayi and Canis dirus dirus. The dire wolf probably evolved from Armbruster's wolf in North America. The largest collection of its fossils has been obtained from the Rancho La Brea Tar Pits in Los Angeles.

Golden jackal wolf-like canid that is native to Southeast Europe and Asia

The golden jackal is a wolf-like canid that is native to Southeast Europe, Southwest Asia, South Asia, and regions of Southeast Asia. Compared with the Arabian wolf, which is the smallest of the gray wolves, the jackal is smaller and possesses shorter legs, a shorter tail, a more elongated torso, a less-prominent forehead, and a narrower and more pointed muzzle. The golden jackal's coat can vary in color from a pale creamy yellow in summer to a dark tawny beige in winter. It is listed as Least Concern on the IUCN Red List due to its widespread distribution and high density in areas with plenty of available food and optimum shelter.

Canid hybrids are the result of interbreeding between different species of the canine (dog) family. They often occur in the wild, in particular between domestic or feral dogs and wild native canids.

Japanese wolf extinct subspecies of mammal

The Japanese wolf (Japanese: ニホンオオカミ is an extinct subspecies of the gray wolf that was once endemic to the islands of Honshū, Shikoku, and Kyūshū in the Japanese archipelago. It is also known as the Honshū wolf. Its binomial name derives from the Greek Hodos and phylax, in reference to Japanese folklore, which portrayed wolves as the protectors of travellers. It was one of two subspecies that were once found in the Japanese archipelago, the other being the Hokkaido wolf.

Caninae subfamily of carnivorans

The Caninae, known as canines, are one of three subfamilies found within the canid family. The other two canid subfamilies are the extinct Borophaginae and Hesperocyoninae. The Caninae includes all living canids and their most recent fossil relatives. Their fossils have been found in Lower Oligocene North America, and they did not spread to Asia until the end of the Miocene, some 7 million to 8 million years ago. Many extinct species of Caninae were endemic to North America, living from 34 million to 11,000 years ago.

<i>Xenocyon</i> sub genus of extinct carnivores

Xenocyon is an extinct subgenus of Canis. The group includes Canis (Xenocyon) africanus, Canis (Xenocyon) antonii and Canis (Xenocyon) falconeri that gave rise to Canis (Xenocyon) lycanoides. The hypercarnivore Xenocyon gave rise to the modern dhole and the African wild dog.

<i>Canis lepophagus</i> species of mammal

Canis lepophagus is an extinct species of canid which was endemic to much of North America during the Early Pliocene. It is notable because its lineage is proposed to have led to both wolves and coyotes.

<i>Eucyon</i> genus of mammals

Eucyon is an extinct genus of small omnivorous coyote-like canid that first appeared in North America during the Miocene, living from 10.3–3.6 Ma and existed for approximately 6.7 million years. The genus is notable because it is proposed that its lineage gave rise to the genus Canis.

Beringian wolf extinct type of wolf that lived during the Ice Age in Alaska, Yukon, and northern Wyoming

The Beringian wolf is an extinct type of wolf that lived during the Ice Age. It inhabited what is now modern-day Alaska, Yukon, and northern Wyoming. Some of these wolves survived well into the Holocene. The Beringian wolf is an ecomorph of the gray wolf and has been comprehensively studied using a range of scientific techniques, yielding new information on the prey species and feeding behavior of prehistoric wolves. It has been determined that these wolves are morphologically distinct from modern North American wolves and genetically basal to most modern and extinct wolves. The Beringian wolf has not been assigned a subspecies classification and its relationship with the extinct European cave wolf is not clear.

Pleistocene coyote subspecies of mammal

The Pleistocene coyote, also known as the Ice Age coyote, is an extinct subspecies of coyote that lived in western North America during the Late Pleistocene era. Most remains of the subspecies were found in southern California, though at least one was discovered in Idaho. It was part of a carnivore guild that included other canids like foxes, gray wolves, and dire wolves.

Megafaunal wolf

The megafaunal wolf was a Late Pleistocene – early Holocene hypercarnivore similar in size to a large extant gray wolf. It had a shorter, broader palate with large carnassial teeth relative to its overall skull size. This adaptation allowed it to prey and scavenge on Pleistocene megafauna. Such an adaptation is an example of phenotypic plasticity. It was once distributed across the northern Holarctic.

Cave wolf Subspecies of mammal

The cave wolf is an extinct subspecies of wolf that lived during the Late Pleistocene Ice Age. It inhabited what is now modern-day western Europe. The Don wolf from eastern Europe is regarded as a taxonomic synonym, which indicates that one subspecies once lived across Europe.

Paleolithic dog Late Pleistocene canine

The Paleolithic dog was a Late Pleistocene canine. They were directly associated with human hunting camps in Europe over 30,000 years ago and it is proposed that these were domesticated. They are further proposed to be either a proto-dog and the ancestor of the domestic dog or an extinct, morphologically and genetically divergent wolf population.

African golden wolf One of the only two wolf species in Africa, along with the Ethiopian wolf

The African golden wolf, also known as the Egyptian jackal or gray jackal, is a canid native to north and northeastern Africa. The species is the descendant of a genetically admixed canid of 72% gray wolf and 28% Ethiopian wolf ancestry. The species is common in northwest and northeast Africa, occurring from Senegal to Egypt in the east, in a range including Morocco, Algeria, Tunisia and Libya in the north to Nigeria, Chad and Tanzania in the south. It is a desert-adapted canid, and is common in plains and steppe areas, including ones lacking abundant water. In the Atlas Mountains, the species has been sighted in elevations as high as 1,800 meters. It is primarily a predator, targeting invertebrates and mammals as large as gazelle fawns, though larger animals are sometimes taken. Other foodstuffs include animal carcasses, human refuse, and fruit. The African golden wolf is a monogamous and territorial animal, whose social structure includes yearling offspring remaining with the family to assist in raising their parents' younger pups.

Evolution of the wolf overview about the evolution of the wolf

The evolution of the wolf occurred over a geologic time scale of at least 300 thousand years. The grey wolf Canis lupus is a highly adaptable species that is able to exist in a range of environments and which possesses a wide distribution across the Holarctic. Studies of modern grey wolves have identified distinct sub-populations that live in close proximity to each other. This variation in sub-populations is closely linked to differences in habitat – precipitation, temperature, vegetation, and prey specialization – which affect cranio-dental plasticity.

<i>Canis arnensis</i> species of mammal

Canis arnensis is an extinct species of canine that was endemic to Mediterranean Europe during the Early Pleistocene. The Arno River dog has been described as a small jackal-like dog. Its anatomy and morphology relate it more to the modern golden jackal than to the larger Etruscan wolf of that time. It is probably the ancestor of modern jackals.

<i>Canis etruscus</i> species of mammal

Canis etruscus is an extinct species of canine that was endemic to Mediterranean Europe during the Early Pleistocene. The Etruscan wolf has been described as a small wolf-like dog. The Etruscan wolf is accepted as the ancestor of C. mosbachensis that is the ancestor of the gray wolf.

<i>Canis mosbachensis</i> species of mammal

Canis mosbachensis, sometimes known as the Mosbach wolf, is an extinct small wolf that once inhabited Eurasia from the Middle Pleistocene era to the Late Pleistocene. It is widely accepted as the ancestor of Canis lupus, the gray wolf.

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