Canis

Coyote Canis latrans, photographed by Dawn Beattie.

Belongs within: Caninae.
Contains: Canis lupus.

The genus Canis includes the true dogs, wolves and jackals; they are relatively large and often highly social canids. Members of this genus are found in Eurasia, Africa and North America, with the dingo C. familiaris dingo also prehistorically introduced to Australia. The domestic dog C. familiaris is generally regarded as a derivative of the grey wolf C. lupus modified by association with humans, and is often treated as a subspecies of the latter. However, some authors have argued for its derivation from a close relative of C. lupus that is now extinct in the wild (Dinets 2015).

Wolf and wolf and wolf and wolf and cub
Published 8 April 2009
Canis rufus, the controversial red wolf of North America, from Steven Hoelzer.

Despite the fact that I’ve been posting on this site for nearly two years now, I think this is just about a first—I’m actually going to write about something I’ve said I was going to write about. I’d better not let it become a habit—people might begin to think that I’m reliable.

In the previous post, I considered writing on “the taxonomy of dingoes and singing dogs, and of the wolf complex in general, [and] the origins of the red wolf (and how the ICZN fumbles on hybrids)“. This is that post. To write about the wolf complex, though, first I’ll have to define it. The phylogenetic analysis of Bardeleben et al. (2005) found a primary division of the genus Canis between the side-striped (Canis adustus) and black-backed (Canis mesomelas) jackals on one hand, and a clade containing the golden jackal (Canis aureus), coyote (Canis latrans), wolf (Canis lupus) and domestic dog (Canis familiaris) on the other. This latter clade was also supported by Zrzavý & Řičánková (2004), who also included therein Canis simensis, the Simien jackal or Ethiopian wolf. These five species, therefore, can be referred to as the wolf complex (or Canis ‘sensu stricto’, if one were to accept Zrzavý & Řičánková’s suggestion of moving the other two species to separate genera, but I don’t know of anyone who has). Relationships within the clade are not yet clearly resolved.

The Indian wolf, Canis pallipes, one of the “subspecies” of Canis lupus that has been regarded as a separate species in recent years. Photo by Rajpal Singh.

Though the four main species of Canis aureus, C. lupus, C. latrans and C. simensis all seem to be safe enough, beyond this it all becomes hazy*. At their broadest circumscriptions, three of the four species are extremely polytypic. Mech (1974) listed thirty-two subspecies for Canis lupus, Bekoff (1977) gave nineteen for Canis latrans, and while I haven’t found a full listing of subspecies for Canis aureus, I think it’s safe to say that there’s a few. Even C. simensis manages to fit in two subspecies (Sillero-Zubiri & Gottelli, 1994), despite having a distribution not much larger than a cereal box (the two subspecies are divided by a minor geographical hiccup known as the Rift Valley). Needless to say, a number of these “subspecies” have been recognised as distinct species at one time or another, particularly various wolf populations such as the eastern North American Canis lycaon, the Indian C. pallipes or the Japanese C. hodophilax. The North African C. lupaster doesn’t seem to be clamouring for separate species status, but authors disagree whether it’s a subspecies of C. aureus or C. lupus. And yes, this is one of those “species concept” things—all members of the wolf clade seem to be pretty much fully interfertile, though behavioral differences may slow down cross-breeding where species overlap.

*It occurs to me that this line is becoming something of a cliché for this site. Honestly, is there any group of organisms out there for which the taxonomy is not hazy?

The Egyptian Canis lupaster, the one that doesn’t know if he’s a wolf or a jackal. Photo by Thomas Krumenacker.

The most hotly contested issue of interfertility in the wolf clade is undoubtedly that involving ‘Canis rufus‘, the red wolf. The name ‘Canis rufus‘* has been applied to a form of Canis once found over a large part of the south-eastern United States, from Texas to Florida (Paradiso & Nowak 1972), but which became extinct in the wild by 1980, before a re-introduced population was established from captive animals in North Carolina in the late 1980s. However, numerous authors have made the suggestion that C. rufus is not a valid ‘species’, but represents a hybrid between C. lupus (or C. lycaon) and C. latrans (Brownlow 1996). As ‘pure’ red wolves became fewer and further between, hybridisation with coyotes became common, further muddying the waters.

*Older references use the name Canis niger, originally applied to the now-extinct Florida red wolf (Canis rufus floridanus). While niger is the older name by some sixty years, the book that it was published in, the Travels of W. Bartram, was declared by the ICZN to be invalid for the purposes of nomenclature, so the next-oldest name swings into use.

The original Canis lupus lupus. The species status of this one, at least, is safe. Photo by Milan Kořínek.

The red wolf was perhaps the academic victim of two malign influences—an unjustified preconception about how speciation works, and the ability of politics to interfere with scientific inference. While no law explicitly states as much (Brownlow 1996), the general policy for conservation in the United States (and, for that matter, most other places in the world) has been that “hybrids” aren’t worth conserving. Instead, there is generally a focus on maintaining “pure” lineages that is sometimes at odds with reality. Also, hybridisation has generally been assumed to be of little importance in animal evolution. The stereotypical view that hybrids between species are infertile (not the case with members of the wolf clade) means that hybrids are assumed to be dead-end oddities. Even the ICZN previously regarded names based on hybrids as invalid, and while this rule was most likely introduced to prevent names based on one-off, individual hybrid specimens (such as a mule), it was also invoked to declare names for populations of hybrid origin to be invalid (the current Code has changed the rules somewhat to remove this ambiguity). This is in stark contrast to the situation in botany, where hybridisation has long been recognised as a major player in the origin of new species, and where the Botanical Code of Nomenclature even has a specific concept of “nothospecies” for taxa of hybrid origin. As a result, the debate over the red wolf became unnecessarily polarised into an argument over whether it was of hybrid origin or a valid species—the possibility that it could be both seems to have never entered consideration.

The taxonomy of the wolf clade is further confused, of course, by the question of how to deal with domestic dogs and their wild derivatives. I’ll refer you to a post by Darren Naish from a couple of years ago on the question of domestic dog origins. Darren refers in that post to the pariah dogs—wild populations of generalised domestic dog-type that are found from southern Asia to Australia, where, of course, they are represented by the dingo.

The New Guinea singing dog, Canis hallstromi (sometimes), photographed by Patti McNeal.

There is no doubt that populations such as the dingo and the New Guinea singing dog are ultimately derived from dogs that arrived in Australasia with the original human settlers. On this basis, the majority of authors have tended to include them with with domestic dogs as Canis familiaris and Canis lupus familiaris. However, these dogs have been living wild in their respective countries for a very long time, and have become morphologically distinct from their ancestors, leading others to separate them as the species Canis dingo and Canis hallstromi (Koler-Matznick et al. 2003)*. Again, the difference seems to be more one of philosophical approaches to what should be regarded as a “species”, with a soupçon of the artificial distinction between “natural” and “altered” conditions. How long does it take for a “feral” population to become a “wild” one?

*One further point (which I’m putting in a footnote because I couldn’t work out how to integrate it into the paragraph) is that these dogs quite possibly became part of the “wild” environment very soon after their arrival with humans, if not immediately (and while there’s a lot of disagreement about when exactly that was, it was at least many tens of thousands of years ago). After all, the modern intensive management of domestic animals did not always apply—in many cases, animals were largely left to roam free, dogs especially so, and their presence was more encouraged than controlled. The dogs that originally arrived in New Guinea and Australia could have been more commensals than domesticates of humans.

The wolf in time
Published 14 August 2012
Black-backed jackal pup Canis mesomelas, photographed by Blake Matheson.

The dogs of the genus Canis include some of the most familiar of all mammals: the wolf Canis lupus, the coyote C. latrans, and of course the domestic dog Canis familiaris. I have already discussed above how these three, together with the golden (Canis aureus) and the Simien (C. simensis) jackals, form a cluster of closely related species (that I’ll refer to as the ‘wolf group’) that are not always clearly separated. Today, I’ll take things a bit further and look at the fossil history of the genus Canis.

Coyote Canis latrans, from Ryan Photographic.

The earliest taxa assigned to the genus Canis are known from the late Miocene, about six million years ago (Tedford et al. 2009). Early Canis have been identified in both Europe (C. cipio) and North America (C. ferox), though there is some uncertainty about whether the European C. cipio should be treated as Canis or assigned to the related, slightly earlier fossil genus Eucyon. Whatever the case, it doesn’t appear to have been long before Canis populations were well and truly established on both continents. The North American Canis ferox was, as far as I can tell, probably not dissimilar to a modern coyote in appearance, and early Canis species probably also resembled coyotes in being fairly generalist predators. In the evolutionary analysis by Tedford et al. (2009), C. ferox was suggested to have begat C. lepophagus at the beginning of the Pliocene, which in turn begat two lineages: one leading to the modern wolf group, the other leading to three North American Plio-Pleistocene species (C. thooides, C. feneus and C. cedazoensis) that were smaller than their ancestor and probably similar in appearance to modern jackals. It is somewhat unfortunate that Tedford et al.‘s analysis did not include the African side-striped (C. adustus) and black-backed (C. mesomelas) jackals, which molecular and morphological analyses have generally agreed lie outside the wolf group. Biogeography alone suggests that the North American ‘jackals’ were probably convergent rather than directly related to the modern African species, but it would be nice to know.

Mounted skeleton of dire wolf Canis dirus, from lora_313. This species probably weighed between 50 to 80 kg, which is comparable in size to a very large dog such as a bullmastiff or great dane.

The modern wolf group diversified in the late Pliocene, including a number of fossil species as well as the modern. The rate of diversification and spread of wolf-group Canis was such that palaeontologists refer to their appearance in the fossil record as the ‘wolf event’, and use it as a marker of the development of the colder tundra climate of the Pleistocene ice ages. Higher diversity in Eurasia suggests that it was probably the centre of diversification, with North American species derived from repeated colonisation. Significant among these was the relatively large C. armbrusteri, a close relative of the grey wolf C. lupus. Canis armbrusteri is notable as the probable ancestor of the late Pleistocene dire wolf C. dirus, made famous by its appearances in the works of Robert E. Howard* and similar authors. As well as being a dominant predator in North America, the dire wolf spread into northwestern South America. A similar large Canis species, C. nehringi, is also known from the same time in Argentina, but the analysis of South American canids by Prevosti (2010) was unable to clearly determine whether C. nehringi was a southern relative of C. dirus or a convergent relative of the Xenocyon lineage.

*A man who spent far too much time thinking about oiled chests if ever there was one.

Dholes Cuon alpinus, from Rajnish Pradhan.

Xenocyon is itself relevant to the history of Canis: first appearing in the late Pliocene, Xenocyon lycaonoides is probably the ancestor of the modern African hunting dog Lycaon pictus and the Asian dhole Cuon alpinus, forming a hypercarnivorous lineage specialised for collaborative hunting of large prey. Phylogenetic analyses of modern taxa have varied as to whether Lycaon and Cuon are the sister group of modern Canis, or whether they are in fact more closely related to the wolf group than are C. adustus or C. mesomelas, rendering Canis paraphyletic. Removal of the latter two species from Canis into separate genera as Schaeffia adusta and Lupulella mesomelas to preserve monophyly has been suggested, but almost universally ignored (as well as failing to resolve the status of the non-wolf-group fossil Canis species). Tedford et al. (2009) even nested the Xenocyon lineage within the wolf group itself, as sister to the Canis lupus-C. dirus group, but one might suspect the influence of convergences to large size and hypercarnivory. Prevosti (2010) placed Lycaon and Cuon in a more standard position just outside the wolf group, but did not consider as many fossil Canis species as Tedford et al.

Remains of Cynotherium sardous (plus some smaller mammal), from here.

The Xenocyon lineage was undoubtedly Eurasian in origin, but the primarily Eurasian X. lycaonoides did spread into northern North America, and a second species X. texanus was found in the Pleistocene of (surprisingly) Texas. The modern dhole Cuon alpinus was also present in North America in the latest Pleistocene, with remains of at least four individuals found in a cave in northeastern Mexico, as well as being found in Europe (Tedford et al. 2009). Also a member of the Xenocyon lineage was the Pleistocene Cynotherium sardous, found on the Mediterranean islands of Sardinia and Corsica (which were a single island when the Mediterranean sea level was lower). Though descended from hypercarnivorous ancestors, Cynotherium became adapted in its island habitat to hunting smaller prey (such as the Sardinian lagomorph Prolagus sardus). Though it retained the simplified dentition of a hypercarnivore, it became smaller and the skull became less reinforced, as befits an animal no longer wrestling down large ungulates (Lyras et al. 2006).

Systematics of Canis
Canis Linnaeus 1758L58
|--+--C. aureus Linnaeus 1758FS15, D15 [incl. C. syriacusT66]
| `--+--C. latrans Say 1823FS15, D15
| | |--C. l. latransGSD74
| | |--C. l. cagottisG69
| | |--C. l. frustrorGSD74
| | |--C. l. goldmaniG69
| | |--C. l. impavidus Allen 1903MB86
| | |--C. l. mearnsi Merriam 1897MB86
| | `--C. l. thamnos Jackson 1949B75
| `--C. simensis Rüppell 1835FS15, D15 [=C. (Simenia) simensisVG78]
| |--C. s. simensisBP87
| `--C. s. citerniiBP87
`--+--+--C. armbrusteri Gidley 1913WT08
| `--C. dirus Leidy 1858FS15, WT08
`--+--C. lycaon Schreber 1775D15 [=C. lupus lycaonGSD74]
| |--C. l. lycaonD15
| |--C. ‘rufus’ floridanusD81
| |--C. ‘niger’ gregoryi Goldman 1937B75 [=C. rufus gregoryiD81]
| `--C. l. rufus Audubon & Bachman 1851D15, FS15, D15 [incl. C. niger Bartram 1791 (nom. inv.)VG78]
`--+--C. lupusFS15
`--+--*C. familiaris Linnaeus 1758GC-BG04 (see below for synonymy)
| |--C. f. familiarisD15
| |--C. f. dingo Meyer 1793 [=C. lupus dingo]D15
| |--C. f. hallstromi Troughton 1957D15
| |--C. f. indica Sykes 1831D15
| `--C. f. novaehollandiae Voigt 1831R64
`--C. variabilis Pei 1934D15, WT08 [=C. lupus variabilisD15]

Canis incertae sedis:
C. africanus Pohle 1928WT08
C. alopex Linnaeus 1758L58
C. anthusJ23
C. antiquusS78
C. antonii Zdansky 1924WT08
C. argentatusG41
C. arnensis Del Campana 1913WT08
C. atroxS78
C. brevicephalus Qiu, Deng & Wang 2004WT08
C. brevirostrisS78
C. cedazoensis Mooser & Dalquest 1975WT08
C. chihliensis Zdansky 1924WT08
C. cipio Crusafont-Pairó 1950WT08
C. davisiV91
C. dingoides Matschie 1915R64
C. edwardii Gazin 1942WT08
C. etruscus Forsyth-Major 1877WT08
C. falconeri Forsyth-Major 1877WT08
C. ferox Miller & Carranza-Castañeda 1998WT08
C. fulvusG41
C. gallaensisS78
C. gezi Kraglievich 1928WT08
C. gregariusC77
C. hartshornianusC77
C. haydeniiC77
C. hodophilax Temminck 1839I92 [=C. lupus hodophilaxD81]
C. hyaena Linnaeus 1758L58
C. lampertiS78
C. lepophagus Johnston 1938WT08
C. longdanensis Qiu, Deng & Wang 2004WT08
C. macdonnellensis Matschie 1915R64
C. mexicanusJ23
C. mosbachensis Soergel 1925WT08 [=C. lupus mosbachensisME05]
C. nehringi Ameghino 1902WT08
C. osorumC77
C. palmidens (Teilhard & Piveteau 1930)WT08
C. priscolatransV91
C. teilhardi Qiu, Deng & Wang 2004WT08
C. temerariusC77
C. terblancheiS78
C. ursinus Cope 1875C77
C. vaferC77
C. wheelerianus Cope 1876C77

Inorganic: Canis familiaris protominilorientalis Okamura 1987O87
Canis lupus protominilorientalis Okamura 1987O87

Nomen rejiciendum: Canis antarcticus Kerr 1792R64

*Canis familiaris Linnaeus 1758GC-BG04 [=C. lupus familiarisD15; incl. Dusicyon hagenbecki Krumbiegel 1949VG78, C57, C. familiaris var. tenggerana Kohlbruge 1896D15]

*Type species of generic name indicated

References

Bardeleben, C., R. L. Moore & R. K. Wayne. 2005. A molecular phylogeny of the Canidae based on six nuclear loci. Molecular Phylogenetics and Evolution 37 (3): 815–831.

Bekoff, M. 1977. Canis latrans. Mammalian Species 79: 1–9.

[B75] Bowles, J. B. 1975. Distribution and biogeography of mammals of Iowa. Special Publications, The Museum, Texas Tech University 9: 1–184.

Brownlow, C. A. 1996. Molecular taxonomy and the conservation of the red wolf and other endangered carnivores. Conservation Biology 10 (2): 390–396.

[BP87] Burton, J. A., & B. Pearson. 1987. Collins Guide to the Rare Mammals of the World. Collins: London.

[C57] Cabrera, A. 1957. Catalogo de los mamiferos de America del Sur. I (Metatheria—Unguiculata—Carnivora). Revista del Museo Argentino de Ciencias Naturales “Bernardino Rivadavia” e Instituto Nacional de Investigacion de Las Ciencias Naturales, Ciencias Zoológicas 4 (1): 1–307.

[C77] Cope, E. D. 1877. Report upon the extinct Vertebrata obtained in New Mexico by parties of the expedition of 1874. Geographical Surveys West of the One Hundredth Meridian 4 (2): i–iv, 1–370.

[D81] Day, D. 1981. The Doomsday Book of Animals: A unique natural history of three hundred vanished species. Ebury Press: London.

[D15] Dinets, V. 2015. The Canis tangle: a systematics overview and taxonomic recommendations. Vavilovskii Zhurnal Genetiki i Selektsii 19 (3): 286–291.

[FS15] Faurby, S., & J.-C. Svenning. 2015. A species-level phylogeny of all extant and late Quaternary extinct mammals using a novel heuristic-hierarchical Bayesian approach. Molecular Phylogenetics and Evolution 84: 14–26.

[GC-BG04] Gentry, A., J. Clutton-Brock & C. P. Groves. 2004. The naming of wild animal species and their domestic derivatives. Journal of Archaeological Science 31: 645–651.

[GSD74] Gipson, P. S., J. A. Sealander & J. E. Dunn. 1974. The taxonomic status of wild Canis in Arkansas. Systematic Zoology 23 (1): 1–11.

[G69] Goodwin, G. G. 1969. Mammals from the State of Oaxaca, Mexico, in the American Museum of Natural History. Bulletin of the American Museum of Natural History 141 (1): 1–269, 40 pls.

[G41] Gulliver, G. 1841. Observations on the blood-corpuscles of the order Ferae. Proceedings of the Zoological Society of London 9: 42–44.

[I92] Iwahashi, J. (ed.) 1992. Reddo Deeta Animaruzu: a pictorial of Japanese fauna facing extinction. JICC: Tokyo.

[J23] James, E. 1823. Account of an Expedition from Pittsburgh to the Rocky Mountains, performed in the years 1819 and ’20, by order of the Hon. J. C. Calhoun, sec’y of war: under the command of Major Stephen H. Long. From the notes of Major Long, Mr. T. Say, and other gentlemen of the exploring party vol. 1. H. C. Carey & I. Lea: Philadelphia.

Koler-Matznick, J., I. L. Brisbin Jr, M. Feinstein & S. Bulmer. 2003. An updated description of the New Guinea singing dog (Canis hallstromi, Troughton 1957). Journal of Zoology 261: 109–118.

[L58] Linnaeus, C. 1758. Systema Naturae per Regna Tria Naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata. Laurentii Salvii: Holmiae.

Lyras, G. A., A. A. E. Van Der Geer, M. D. Dermitzakis & J. De Vos. 2006. Cynotherium sardous, an insular canid (Mammalia: Carnivora) from the Pleistocene of Sardinia (Italy), and its origin. Journal of Vertebrate Paleontology 26 (3): 735–745.

[MB86] Matson, J. O., & R. H. Baker. 1986. Mammals of Zacatecas. Special Publications, Museum of Texas Tech University 24: 1–88.

Mech, L. D. 1974. Canis lupus. Mammalian Species 37: 1–6.

[ME05] Moullé, P.-E., A. Echassoux, F. Lacombat, E. Desclaux & S. Bailon. 2005. L’environnement animal des premiers habitants de l’Europe méditerranéenne: les grands mammifères contemporains de l’homme du Vallonnet, données taxonomiques et biostratigraphiques pour la deuxième moitie du Pléistocène inférieur. BAR International Series 1364: 105–113.

[O87] Okamura, C. 1987. New facts: Homo and all Vertebrata were born simultaneously in the former Paleozoic in Japan. Original Report of the Okamura Fossil Laboratory 15: 347–573.

Paradiso, J. L., & R. M. Nowak. 1972. Canis rufus. Mammalian Species 22: 1–4.

Prevosti, F. J. 2010. Phylogeny of the large extinct South American canids (Mammalia, Carnivora, Canidae) using a “total evidence” approach. Cladistics 26: 456-481.

[R64] Ride, W. D. L. 1964. A list of mammals described from Australia between the years 1933 and 1963 (comprising newly proposed names and additions to the Australian faunal list). Australian Mammal Society Bulletin 7 (Suppl.): 1–15.

[S78] Savage, R. J. G. 1978. Carnivora. In: Maglio, V. J., & H. B. S. Cooke (eds) Evolution of African Mammals pp. 249–267. Harvard University Press: Cambridge (Massachusetts).

Sillero-Zubiri, C., & D. Gottelli. 1994. Canis simensis. Mammalian Species 485: 1–6.

Tedford, R. H., X. Wang & B. E. Taylor. 2009. Phylogenetic systematics of the North American fossil Caninae (Carnivora: Canidae). Bulletin of the American Museum of Natural History 325: 1–218.

[T66] Tristram, H. B. 1866. Report on the mammals of Palestine. Proceedings of the Zoological Society of London 1866: 84–93.

[V91] Valkenburgh, B. van. 1991. Iterative evolution of hypercarnivory in canids (Mammalia: Carnivora): evolutionary interactions among sympatric predators. Paleobiology 17 (4): 340–362.

[VG78] Van Gelder, R. G. 1978. A review of canid classification. American Museum Novitates 2646: 1–10.

[WT08] Wang, X., & R. H. Tedford. 2008. Dogs: Their fossil relatives and evolutionary history. Columbia University Press: New York.

Zrzavý, J., & V. Řičánková. 2004. Phylogeny of Recent Canidae (Mammalia, Carnivora): relative reliability and utility of morphological and molecular datasets. Zoologica Scripta 33 (4): 311–333.

Leave a comment

Your email address will not be published. Required fields are marked *