Subspecies of Canis lupus

Canis lupus has 37 subspecies currently described, including the dingo, Canis lupus dingo, and the domestic dog, Canis lupus familiaris, and many subspecies of wolf throughout the Northern Hemisphere. The nominate subspecies is Canis lupus lupus.

Canis lupus is assessed as least concern by the IUCN, as its relatively widespread range and stable population trend mean that the species, at global level, does not meet, or nearly meet, any of the criteria for the threatened categories. However, some local populations are classified as endangered, and some subspecies are endangered or extinct.

Biological taxonomy is not fixed, and placement of taxa is reviewed as a result of new research. The current categorization of subspecies of Canis lupus is shown below. Also included are synonyms, which are now discarded duplicate or incorrect namings, or in the case of the domestic dog synonyms, old taxa referring to subspecies of domestic dog which, when the dog was declared a subspecies itself, had nowhere else to go. Common names are given but may vary, as they have no set meaning.

Taxonomy
Canis lupus was recorded by Carl Linnaeus in his publication Systema Naturae in 1758. The Latin classification translates into English as "dog wolf". The subspecies of Canis lupus are listed in Mammal Species of the World. The nominate subspecies is the Eurasian wolf (Canis lupus lupus), also known as the common wolf.

For Eurasia, in 1995 mammalogist Robert Nowak recognized five subspecies from Eurasia based on skull morphology; C. l. lupus, C. l. albus, C. l. pallipes, C. l. cubanensis and C. l. communis. In 2003, Nowak also recognized the distinctiveness of C. l. arabs, C. l. hattai, C. l. hodophilax and C. l. lupaster.

In 1944, American zoologist Edward Goldman recognized as many as 23 subspecies in North America, based on morphology alone. In 1959, E. Raymond Hall proposed that there had been 24 subspecies of lupus in North America. In 1970, L David Mech proposed that there was "probably far too many sub specific designations...in use" as most did not exhibit enough points of differentiation to be classified as a separate subspecies. The 24 subspecies were accepted by many authorities in 1981 and these were based on morphological or geographical differences or a unique history. However, in 1996, Ronald M. Nowak and Nick E. Federoff challenged Hall's 24 subspecies and proposed that based on detailed skull comparisons there had only been five: C. l. occidentalis, C. l. nubilus, C. l. arctos, C. l. baileyi and C. l. lycaon. Both classifications are accepted in North America.

, 37 subspecies of C. lupus are recognised by MSW3, however the classification of several as either species or subspecies has recently been challenged.


 * Further information: Disputed subspecies and species

History of classification

 * ''See further: Evolution of the wolf - Divergence with the coyote

Eastern and red wolves
In 2000, a genetic study of canids from Algonquin Provincial Park indicated that C. l. lycaon was a separate species from C. lupus, more closely related to C. rufus. In a monograph prepared within the United States Fish and Wildlife Service (USF&WS), Chambers et al. (2012) reviewed many genetic studies and concluded that the eastern wolf and red wolf are separate species from the gray wolf, having originated in North America 150,000–300,000 years ago from the same line as coyotes. The Chambers review concluded that the subspecific status of C. l. arctos is doubtful, as Arctic wolf populations do not possess unique haplotypes. However, the Chambers review became controversial, forcing the USF&WS to commission a peer review of it, known as NCAES (2014). This peer review concluded that "virtually all taxonomic conclusions from Chambers et al. are accepted uncritically." Director of RESOLVE's Science Program, Steven Courtney, who was in charge of the peer review, had also noted that the Chambers conclusion that the eastern wolf should be listed outside the species limits of the gray wolf was based primarily on two non-recombining markers – those being mtDNA and sex chromosome – which the other panelists agreed unanimously "is insufficient to determine the existence of a species and specifically is completely insufficient for ruling out the alternative hypothesis that the pattern is explained by ancient (and recent) hybridization between C. lupus and C. latrans". Evolutionary biologist Dr. Robert Wayne of the UCLA Department of Ecology and Evolutionary Biology further elaborated that the Chambers review on the taxonomy of the eastern wolf not only suffered from insufficient sampling but that it was also biased in terms of attributing the presences of the gray wolf Y chromosomes in the modern day eastern wolves to two unfounded hypotheses: that C. lupus was historically absent in the eastern USA by C. lycaon followed with the suggestion of the former's invasion into the eastern third of North America and later introgressing into the latter's gene pool, and that the gray wolf Y chromosomes discovered in the Algonquin Provincial Park's eastern wolf samples originated from domestic dogs.

Two subsequent reviews of updated research based on the 2013 and 2014 reviews, one commissioned to the Wildlife Management Institute by the USFWS, and one journal review, concluded that historically there were four unique canid species in North America, gray wolf, eastern wolf, coyote, and dog, and that "the red wolf may be conspecific with the eastern wolf". This view consistent with the idea that the coyote and gray wolf did not historically range into the southeastern United States. These reviews and a 2015 genetics study, the most comprehensive to date, led the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) in May, 2015 to change the designation of the eastern wolf back into a distinct species, Canis lycaon. However, the previous assertion that gray wolves did not occur in the eastern third of the United States is still heavily ill-founded by the newer genetic study's lead authors, such as Dr. Linda Y. Rutledge, who noted in the conclusions that "the recognition of the eastern wolf as a separate species does not exclude the possibility that a grey wolf × eastern wolf hybrid animal (previously identified as Canis lupus lycaon, boreal/Ontario-type), similar to a Great Lakes boreal wolf currently located in the Great Lakes states and across Manitoba, northern Ontario, and northern Quebec, historically inhabited the northeastern United States alongside eastern wolves, and there is some evidence to support the historical presence of both Canis types." The study also suggests that the coyote markers present in the Canis lupus populations that currently occupy the western Great Lakes states and western Ontario may have been historically circuited into the population by the eastern wolves since pure gray wolves in the wild rarely hybridize with coyotes whereas eastern wolves have a history of hybridizing with both species.

List of subspecies
Subspecies recognized by MSW3 and divided into Old World and New World:

Apennine wolf
The Italian wolf was first recognised as a distinct subspecies Canis lupus italicus in 1921 by zoologist Giuseppe Altobello. Altobello's classification was later rejected by several authors, including Reginald Innes Pocock, who synonymised C. l. italicus with C. l. lupus. In 2002, the noted paleontologist R.M. Nowak reaffirmed the morphological distinctiveness of the Italian wolf and recommended the recognition of Canis lupus italicus. A number of DNA studies have found the Italian wolf to be genetically distinct. In 2004, the genetic distinction of the Italian wolf subspecies was supported by analysis which consistently assigned all the wolf genotypes of a sample in Italy to a single group. This population also showed a unique mitochondrial DNA control-region haplotype, the absence of private alleles and lower heterozygosity at microsatellite loci, as compared to other wolf populations. In 2010, a genetic analysis indicated that a single wolf haplotype (w22) unique to the Apennine Peninsula, and one of the two haplotypes (w24, w25) unique to the Iberian Peninsula, belonged to the same haplogroup as the prehistoric wolves of Europe. Another haplotype (w10) was found to be common to the Iberian peninsula and the Balkans. These three populations with geographic isolation exhibited a near lack of gene flow, and spatially correspond to three glacial refugia.

The taxonomic reference Mammal Species of the World (2005) does not recognize Canis lupus italicus, however NCBI/Genbank publishes research papers under that name.

Iberian wolf
The Iberian wolf was first recognised as a distinct subspecies (Canis lupus signatus) in 1907 zoologist Ángel Cabrera (naturalist). The wolves of Iberian peninsula have morphologically distinct features from other Eurasian wolves and each are considered by their researchers to represent their own subspecies. The taxonomic reference Mammal Species of the World (2005) does not recognize Canis lupus signatus, however NCBI/Genbank does list it.

Himalayan wolf and Indian gray wolf
The Himalayan wolf is formed by one haplotype that currently falls within the Tibetan wolf (Canis lupus chanco) subspecies, but based on mDNA sequencing has been proposed as a separate species Canis himalayensis. The Indian gray wolf is formed by two closely related haplotypes that fall within the Indian wolf (Canis lupus pallipes) subspecies, but based on mDNA sequencing has been proposed as a separate species Canis indica. Neither proposal has been endorsed because they relied on a limited number of museum and zoo samples that may not have been representative of the wild population, and a call for further fieldwork has been made. Based on a fossil record estimate that the divergence time between the coyote and the wolf lineages occurred one million years ago and with an assumed wolf mutation rate, one study estimated the time of divergence of the Himalayan wolf and the Indian gray from the wolf/dog ancestor to be 800,000 years and 400,000 years ago respectively. Another study, which expressed some concerns with the earlier study, gave an estimate of 630,000 ago years and 270,000 ago years respectively. During Pleistocene glaciations these wolf lineages were isolated in refuges. In 2007, a study found that the Indian gray wolf was basil to all extant gray wolves and that the Himalayan wolf belonged to a different clade. In 2010, a study found that these two wolves formed a separate clade being 6 mutations distant from the extant gray wolf, which indicated distinct (i.e. different) lineages. In 2012, a limited genetic analysis of the scats of 2 Himalayan wolves from remote and widely separated areas reconfirmed their basal lineage.

The taxonomic reference Mammal Species of the World (2005) does not recognize Canis himalayensis nor Canis indica, however NCBI/Genbank lists a new subspecies Canis lupus himalayensis as separate from Canis lupus chanco, and a new subspecies Canis lupus indica as separate from Canis lupus pallipes.


 * Further information: Himalayan wolf and Indian gray wolf

Tibetan wolf
In 2009, the Tibetan wolf was found to be genetically distinct enough to propose a separate species. In 2011, another genetic study found that the Tibetan wolf might be an archaic pedigree within the wolf subspecies, however the study defined Canis lupus laniger as the Tibetan wolf distinct from Canis lupus chanco the Mongolian wolf. In 2013, a major genetic study of dogs and wolves included the DNA sequences of 2 Tibetan wolves but then "excluded two aberrant modern wolf sequences from this analysis since their phylogenetic positioning suggests only a distant relationship to all extant gray wolves and their taxonomic classification as a member of Canis lupus or a separate sub-species is a matter of debate." The taxonomic reference Mammal Species of the World (2005) does not recognize Canis lupus laniger, however NCBI/Genbank lists it as the Tibetan wolf, and separately Canis lupus chanco as the Mongolian wolf.

Coastal wolves
A study of the three coastal wolves indicated a close phylogenetic relationship across regions that are geographically and ecologically contiguous, and the study proposed that Canis lupus ligoni (Alexander Archipelago wolf), Canis lupus columbianus (British Columbia wolf), and Canis lupus crassodon (Vancouver Island wolf) should be recognized as a single subspecies of Canis lupus. They share the same habitat and prey species, and form one study's 6 identified North American ecotypes - a genetically and ecologically distinct population separated from other populations by their different type of habitat.

Eastern wolf
The eastern wolf has two proposals over its origin. One is that the eastern wolf is a distinct species (C. lycaon) that evolved in North America, as opposed to the gray wolf that evolved in the Old World, and is related to the red wolf. The other is that it is derived from admixture between gray wolves which inhabited the Great Lakes area and coyotes, forming a hybrid that was classified as a distinct species by mistake. The taxonomic reference Mammal Species of the World (2005) does not recognize Canis lycaon, however NCBI/Genbank lists it.

Red wolf
The red wolf is an enigmatic taxon of which there are two proposals over its origin. One is that the red wolf was a distinct species (C. rufus) that has undergone human-influenced admixture with coyotes. The other is that it was never a distinct species but was derived from admixture between coyotes and gray wolves, due to the gray wolf population being eliminated by humans. The taxonomic reference Mammal Species of the World (2005) does not recognize Canis rufus, however NCBI/Genbank lists it.