Subspecies of Canis lupus

Taxonomy

The species Canis lupus was first recorded by Carl Linnaeus in his publication Systema Naturae in 1758, with the Latin classification translating into the English words "dog wolf".

A subspecies is the taxonomic rank below species. When geographically separate populations of a species exhibit recognizable phenotypic differences, biologists may identify these as separate subspecies; a subspecies is a recognized local variant of a species. The thirty-seven subspecies of Canis lupus are listed in Mammal Species of the World third edition that was published in 2005. The nominate subspecies is the Eurasian wolf (Canis lupus lupus), also known as the common wolf. The subspecies includes the domestic dog, dingo, eastern wolf and red wolf. However, the classification of several as either species or subspecies has recently been challenged.

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 2005, MSW3 included C. l. filchneri. In 2003, two forms were distinguished in southern China and Inner Mongolia as being separate from C. l. chanco and C. l. filchneri and have yet to be named.

For North America, in 1944 the 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.

List of subspecies

Subspecies recognized by MSW3 as of 2005 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 by zoologist Ángel Cabrera. 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

The Himalayan wolf is a proposed clade within the Tibetan wolf (Canis lupus filchneri) that is distinguished by its mitochondrial DNA, which is basal to all other wolves including other Tibetan wolves. The taxonomic status of this wolf clade is disputed, with the separate species Canis himalayensis being proposed based on two limited DNA studies. The proposal has not 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. The taxonomic reference Mammal Species of the World (2005) does not recognize Canis himalayensis, however NCBI/Genbank lists a new subspecies Canis lupus himalayensis.

Indian gray wolf

The Indian gray wolf is a proposed clade within the Indian wolf (Canis lupus pallipes) that is distinguished by its mitochondrial DNA, which is basal to all other wolves except for the proposed Himalayan wolf. The taxonomic status of this wolf clade is disputed, with the separate species Canis indica being proposed based on two limited DNA studies. The proposal has not 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. The taxonomic reference Mammal Species of the World (2005) does not recognize Canis indica, however NCBI/Genbank lists a new subspecies Canis lupus indica.

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.