''Xenocyon'' ("strange dog") is an extinct group of canids, either considered a distinct

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

or a

subgenus In biology, a subgenus ( subgenera) is a taxonomic rank directly below genus. In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed between the ge ...

of ''

Canis ''Canis'' is a genus of the Caninae which includes multiple extant taxon, extant species, such as Wolf, wolves, dogs, coyotes, and golden jackals. Species of this genus are distinguished by their moderate to large size, their massive, well-develo ...

''. The group includes ''Canis'' (''Xenocyon'') ''africanus'', ''Canis'' (''Xenocyon'') ''antonii'' and ''Canis'' (''Xenocyon'') ''falconeri'' that gave rise to ''Canis'' (''Xenocyon'') ''lycanoides''. The

hypercarnivorous A hypercarnivore is an animal that has a diet that is more than 70% meat, either via active predation or by scavenging. The remaining non-meat diet may consist of non-animal foods such as fungi, fruits or other plant material. Some extant example ...

''Xenocyon'' is thought to be closely related and possibly ancestral to modern

dhole The dhole ( ; ''Cuon alpinus'') is a canid native to South, East and Southeast Asia. It is anatomically distinguished from members of the genus ''Canis'' in several aspects: its skull is convex rather than concave in profile, it lacks a third ...

and the

African wild dog The African wild dog (''Lycaon pictus''), also called painted dog and Cape hunting dog, is a wild canine native to sub-Saharan Africa. It is the largest wild canine in Africa, and the only extant member of the genus '' Lycaon'', which is disti ...

, as well as the insular Sardinian dhole.

Taxonomy

''Xenocyon'' is proposed as a subgenus of ''Canis'' named ''Canis'' (''Xenocyon''). One taxonomic authority proposes that as part of this subgenus, the group named ''Canis'' (''Xenocyon'') ex gr. ''falconeri'' (ex gr. meaning "of the group including") would include all of the large hypercarnivorous canids that inhabited the

Old World The "Old World" () is a term for Afro-Eurasia coined by Europeans after 1493, when they became aware of the existence of the Americas. It is used to contrast the continents of Africa, Europe, and Asia in the Eastern Hemisphere, previously ...

during the Late Pliocene–Early Pleistocene: ''Canis'' (''Xenocyon'') ''africanus'' in

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

, ''Canis'' (''Xenocyon'') ''antonii'' in

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

and ''Canis'' (''Xenocyon'') ''falconeri'' in

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

. Further, these three could be regarded as extreme geographical variations within the one

taxon In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...

. This group was hypercarnivorous, had a large body size that is comparable with the northern populations of the modern

gray wolf The wolf (''Canis lupus''; : wolves), also known as the grey wolf or gray wolf, is a canine native to Eurasia and North America. More than thirty subspecies of ''Canis lupus'' have been recognized, including the dog and dingo, though gr ...

(''Canis lupus'') and are characterized by a short

neurocranium In human anatomy, the neurocranium, also known as the braincase, brainpan, brain-pan, or brainbox, is the upper and back part of the skull, which forms a protective case around the brain. In the human skull, the neurocranium includes the cal ...

relative to their skull size. The ancestral condition for canids is to have five toes on their forelimbs, but by the

Early Pleistocene The Early Pleistocene is an unofficial epoch (geology), sub-epoch in the international geologic timescale in chronostratigraphy, representing the earliest division of the Pleistocene Epoch within the ongoing Quaternary Period. It is currently esti ...

this lineage had reduced this to four, which is also a characteristic feature of the modern

(''Lycaon pictus''). The African wild dog cannot be positively identified in the

fossil record A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

of eastern Africa until the middle Pleistocene, and identifying the oldest ''Lycaon'' fossil is difficult because these are hard to distinguish from ''Canis'' (''Xenocyon'') ''africanus''. Some authors consider ''Canis'' (''Xenocyon'') ''lycanoides'' as ancestral to the genera '' Lycaon'' and ''

Cuon The dhole ( ; ''Cuon alpinus'') is a Canidae, canid native to South Asia, South, East Asia, East and Southeast Asia. It is anatomically distinguished from members of the genus ''Canis'' in several aspects: its skull is convex rather than conca ...

''. Therefore, one taxonomic authority has proposed that all of the ''Canis'' (''Xenocyon'') group should be reclassified into the genus ''Lycaon''. This would form three

chronospecies A chronospecies is a species derived from a sequential development pattern that involves continual and uniform changes from an extinct ancestral form on an evolutionary scale. The sequence of alterations eventually produces a population that is p ...

: ''Lycaon falconeri'' during the

Late Pliocene Late or LATE may refer to: Everyday usage * Tardy, or late, not being on time * Late (or the late) may refer to a person who is dead Music * Late (The 77s album), ''Late'' (The 77s album), 2000 * Late (Alvin Batiste album), 1993 * Late!, a pseudo ...

of Eurasia, ''Lycaon lycaonoides'' during the Early Middle Pleistocene of Eurasia and Africa and ''Lycaon pictus'' from the Middle Late Pleistocene to present.

Species

''Canis'' (''Xenocyon'') ''africanus''

The species was originally named ''Canis africanus'' (Pohle 1928) but was later reassigned as ''Canis'' (''Xenocyon'') ''africanus''. It existed during the

and

of Africa.

''Canis'' (''Xenocyon'') ''antonii''

The species was originally named ''Canis antonii'' (Zdansky 1924) but was later reassigned as ''Canis'' (''Xenocyon'') ''antonii''. It existed during the late Pliocene and Early Pleistocene of Asia. The name was applied to Late Pliocene fossils of canids with hypercarnivorous dentition that were found in China at the sites Loc. 33 (

Yangshao The Yangshao culture ( zh, c=仰韶文化, p=Yǎngsháo wénhuà) was a Neolithic culture that existed extensively along the middle reaches of the Yellow River in China from around 5000 BC to 3000 BC. The Yangshao culture saw social and ...

Henan Henan; alternatively Honan is a province in Central China. Henan is home to many heritage sites, including Yinxu, the ruins of the final capital of the Shang dynasty () and the Shaolin Temple. Four of the historical capitals of China, Lu ...

), Loc. 64 (

Zhili Zhili, alternately romanized as Chihli, was a northern administrative region of China since the 14th century that lasted through the Ming dynasty and Qing dynasty until 1911, when the region was dissolved, converted to a province, and renamed ...

Province) and Fancun,

Shanxi Shanxi; Chinese postal romanization, formerly romanised as Shansi is a Provinces of China, province in North China. Its capital and largest city of the province is Taiyuan, while its next most populated prefecture-level cities are Changzhi a ...

Province. The species was recorded in Europe as ''Canis'' (''Xenocyon'') ''falconeri''.

''Canis'' (''Xenocyon'') ''falconeri''

Upper

Valdarno The Valdarno is the valley of the river Arno, from Florence to the sea. The name applies to the entire river basin, though usage of the term generally excludes Casentino and the valleys formed by major tributaries. Some towns in the area: * R ...

is the name given to that part of the

Arno The Arno is a river in the Tuscany region of Italy. It is the most important river of central Italy after the Tiber. Source and route The river originates on Monte Falterona in the Casentino area of the Apennines, and initially takes a sou ...

valley situated in the provinces of

Florence Florence ( ; ) is the capital city of the Italy, Italian region of Tuscany. It is also the most populated city in Tuscany, with 362,353 inhabitants, and 989,460 in Metropolitan City of Florence, its metropolitan province as of 2025. Florence ...

and

Arezzo Arezzo ( , ; ) is a city and ''comune'' in Italy and the capital of the Province of Arezzo, province of the same name located in Tuscany. Arezzo is about southeast of Florence at an elevation of Above mean sea level, above sea level. As of 2 ...

, Italy. The region is bounded by the

Pratomagno The Pratomagno is a mountain range, which has the Arno River on both sides: to the west is the upper Valdarno and to the east is the Casentino. It lies north-west of the city of Arezzo, in Tuscany, Italy Italy, officially the Italian Repu ...

mountain range to the north and east and by the Chianti mountains to the south and west. The Upper Valdarno Basin has provided the remains of three fossil canid species dated to the Late

Villafranchian Villafranchian age ( ) is a period of geologic time (3.5–1.0 Ma) spanning the Late Pliocene and Early Pleistocene used more specifically with European Land Mammal Ages. Named by Italian geologist Lorenzo Pareto for a sequence of terrestrial se ...

era of Europe 1.9-1.8 million years ago that arrived with a faunal turnover around that time (

). It is here that the Swiss paleontologist Charles Immanuel Forsyth Major discovered Falconer's wolf (''Canis falconeri'') (Forsyth Major 1877). The species was later reassigned as ''Canis'' (''Xenocyon'') ''falconeri'', but was later regarded as the European arrival of ''Canis'' (''Xenocyon'') ''antonii''. The species gave rise to ''Canis'' (''Xenocyon'') ''lycanoides''.

''Canis'' (''Xenocyon'') ''lycaonoides''

The species was originally named ''Xenocyon lycaonoides'' (Kretzoi 1938) but was later reassigned as ''Canis'' (''Xenocyon'') ''lycanoides''. Another view is that ''lycaonoides'' and ''falconeri'' should be classified under genus ''Lycaon'', to give the descent of 3 chronospecies: ''L. falconeri'' Late Pliocene of Eurasia → ''L. lycaonoides'' Early Pleistocene and the beginning of the

Middle Pleistocene The Chibanian, more widely known as the Middle Pleistocene (its previous informal name), is an Age (geology), age in the international geologic timescale or a Stage (stratigraphy), stage in chronostratigraphy, being a division of the Pleistocen ...

of Eurasia and Africa → ''L. pictus'' Middle Pleistocene to the present day. The diversity of the wolf-sized species decreased by the end of the Early Pleistocene and into the Middle Pleistocene of Europe and Asia. These wolves include the large hypercarnivorous ''Canis'' (''Xenocyon'') ''lycaonoides'' that was comparable in size with the modern gray wolf (''C. lupus'') northern populations and the small Mosbach wolf ('' C. mosbachensis'') that is comparable in size to the modern Indian wolf (''C. l. pallipes''). Both types of wolves could be found existing from England and Greece across Europe to the high latitudes of Siberia through to Transbaikalia, Tajikistan, Mongolia, and China. Remains of both canid species are also found in Ubeidiya, in the southern Levant. The true gray wolves did not make an appearance until the end of the Middle Pleistocene, 500-300 thousand years ago. Fossil evidence to dated 1.8 million years ago from

Dmanisi Dmanisi ( ka, დმანისი, tr, , ) is a town and archaeological site in the Kvemo Kartli region of Georgia (country), Georgia approximately 93 km southwest of the nation’s capital Tbilisi in the river valley of Mashavera. Abandoned i ...

, Georgia in the southern Caucasus suggests that they were cooperative hunters which cared for their sick, injured and disabled pack members similar to the modern grey wolf. It preyed on

antelope The term antelope refers to numerous extant or recently extinct species of the ruminant artiodactyl family Bovidae that are indigenous to most of Africa, India, the Middle East, Central Asia, and a small area of Eastern Europe. Antelopes do ...

deer A deer (: deer) or true deer is a hoofed ruminant ungulate of the family Cervidae (informally the deer family). Cervidae is divided into subfamilies Cervinae (which includes, among others, muntjac, elk (wapiti), red deer, and fallow deer) ...

elephant Elephants are the largest living land animals. Three living species are currently recognised: the African bush elephant ('' Loxodonta africana''), the African forest elephant (''L. cyclotis''), and the Asian elephant ('' Elephas maximus ...

calves,

aurochs The aurochs (''Bos primigenius''; or ; pl.: aurochs or aurochsen) is an extinct species of Bovini, bovine, considered to be the wild ancestor of modern domestic cattle. With a shoulder height of up to in bulls and in cows, it was one of t ...

baboon Baboons are primates comprising the biology, genus ''Papio'', one of the 23 genera of Old World monkeys, in the family Cercopithecidae. There are six species of baboon: the hamadryas baboon, the Guinea baboon, the olive baboon, the yellow ba ...

wild horse The wild horse (''Equus ferus'') is a species of the genus Equus (genus), ''Equus'', which includes as subspecies the modern domestication of the horse, domesticated horse (''Equus ferus caballus'') as well as the Endangered species, endangered ...

s and possibly

human Humans (''Homo sapiens'') or modern humans are the most common and widespread species of primate, and the last surviving species of the genus ''Homo''. They are Hominidae, great apes characterized by their Prehistory of nakedness and clothing ...

s. It was probably the ancestor of the

(''Lycaon pictus'') and possibly the

(''Cuon alpinus'') of southeastern Asia, the extinct Sardinian dhole (''Cynotherium sardous'') and perhaps two extinct Javanese dogs (Merriam's dog ('' Megacyon merriami'') and the Trinil dog ('' Mececyon trinilensis'')). Just before the appearance of the

dire wolf The dire wolf (''Aenocyon dirus'' ) is an Extinction, extinct species of Caninae, canine which was native to the Americas during the Late Pleistocene and Early Holocene epochs (125,000–10,000 years ago). The species was named in 1858, four y ...

(''Aenocyon dirus''), North America was invaded by the genus ''Xenocyon'', which was as large as ''A. dirus'' and more hypercarnivorous. The fossil record shows them as rare and it is assumed that they could not compete with the newly derived ''A. dirus''. These have been ascribed to ''Xenocyon lycaonoides'', with ''Xenocyon texanus'' from as far south as Texas as its

taxonomic synonym In taxonomy, the scientific classification of living organisms, a synonym is an alternative scientific name for the accepted scientific name of a taxon. The Botanical nomenclature, botanical and Zoological nomenclature, zoological codes of nomencl ...

References

{{Taxonbar, from=Q19692941 Canis Prehistoric canines Pleistocene carnivorans Pleistocene mammals of Africa Fossil taxa described in 1938 Animal subgenera Pleistocene mammals of Europe