Xenocyon Temporal range: Pliocene to Middle Pleistocene | |
---|---|
Canis (Xenocyon) falconeri skull | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Carnivora |
Family: | Canidae |
Genus: | Canis |
Subgenus: | † Xenocyon Kretzoi, 1938 [1] |
Species | |
Parts of this article (those related to systematics concerning recent species https://doi.org/10.1016/j.cub.2015.06.060) need to be updated.(February 2023) |
Xenocyon ("strange dog") is an extinct group of canids, either considered a distinct genus [2] or a subgenus of Canis . The group includes Canis (Xenocyon) africanus, Canis (Xenocyon) antonii and Canis (Xenocyon) falconeri that gave rise to Canis (Xenocyon) lycanoides. [3] The hypercarnivorous Xenocyon is thought to be closely related and possibly ancestral to modern dhole and the African wild dog, [4] : p149 as well as the insular Sardinian dhole. [5]
Xenocyon is proposed as a subgenus of Canis named Canis (Xenocyon). [3] 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 during the Late Pliocene–Early Pleistocene: Canis (Xenocyon) africanus in Africa, Canis (Xenocyon) antonii in Asia and Canis (Xenocyon) falconeri in Europe. Further, these three could be regarded as extreme geographical variations within the one taxon. This group was hypercanivorous, had a large body size that is comparable with the northern populations of the modern gray wolf (Canis lupus) and are characterized by a short neurocranium relative to their skull size. [3]
The ancestral condition for canids is to have five toes on their forelimbs, but by the Early Pleistocene this lineage had reduced this to four, which is also a characteristic feature of the modern African wild dog (Lycaon pictus). [6] [7] The African wild dog cannot be positively identified in the fossil record of eastern Africa until the middle Pleistocene, [8] and identifying the oldest Lycaon fossil is difficult because these are hard to distinguish from Canis (Xenocyon) africanus. [7] Some authors consider Canis (Xenocyon) lycanoides as ancestral to the genera Lycaon and Cuon . [9] [10] [11] [4] : p149 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: Lycaon falconeri during the Late Pliocene of Eurasia, Lycaon lycaonoides during the Early Middle Pleistocene of Eurasia and Africa and Lycaon pictus from the Middle Late Pleistocene to present. [6]
The species was originally named Canis africanus (Pohle 1928) [12] but was later reassigned as Canis (Xenocyon) africanus. It existed during the Late Pliocene and Early Pleistocene of Africa. [3]
The species was originally named Canis antonii (Zdansky 1924) [13] but was later reassigned as Canis (Xenocyon) antonii. It existed during the late Pliocene and Early Pleistocene of Asia. [3] The name was applied to Late Pliocene fossils of canids with hypercarnivorous dentition that were found in China at the sites Loc. 33 (Yangshao, Henan), Loc. 64 (Zhili Province) and Fancun, Shanxi Province. [14] The species was recorded in Europe as Canis (Xenocyon) falconeri. [6]
Upper Valdarno is the name given to that part of the Arno valley situated in the provinces of Florence and Arezzo, Italy. The region is bounded by the Pratomagno 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 era of Europe 1.9-1.8 million years ago that arrived with a faunal turnover around that time (Early Pleistocene). It is here that the Swiss paleontologist Charles Immanuel Forsyth Major discovered Falconer's wolf (Canis falconeri) (Forsyth Major 1877). [15] The species was later reassigned as Canis (Xenocyon) falconeri, [3] but was later regarded as the European arrival of Canis (Xenocyon) antonii. [6] The species gave rise to Canis (Xenocyon) lycanoides. [3]
The species was originally named Xenocyon lycaonoides (Kretzoi 1938) [1] but was later reassigned as Canis (Xenocyon) lycanoides. [3]
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 of Eurasia and Africa → L. pictus Middle Pleistocene to the present day. [6]
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. [14] Remains of both canid species are also found in Ubeidiya, in the southern Levant. [16] The true gray wolves did not make an appearance until the end of the Middle Pleistocene, 500-300 thousand years ago. [14]
Fossil evidence to dated 1.8 million years ago from Dmanisi, 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. [17]
It preyed on antelope, deer, elephant calves, aurochs, baboons, wild horses and possibly humans. It was probably the ancestor of the African wild dog (Lycaon pictus) and possibly the dhole (Cuon alpinus) of southeastern Asia, the extinct Sardinian dhole (Cynotherium sardous) [6] [18] [9] and perhaps two extinct Javanese dogs (Merriam's dog ( Megacyon merriami ) and the Trinil dog ( Mececyon trinilensis )). [19] [20]
Just before the appearance of the dire wolf (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. [4] These have been ascribed to Xenocyon lycaonoides, with Xenocyon texanus from as far south as Texas as its taxonomic synonym. [21]
Canidae is a biological family of dog-like carnivorans, colloquially referred to as dogs, and constitutes a clade. A member of this family is also called a canid. The family includes three subfamilies: the Caninae, and the extinct Borophaginae and Hesperocyoninae. The Caninae are known as canines, and include domestic dogs, wolves, coyotes, foxes, jackals and other species.
The dhole is a canid native to South, East and Southeast Asia. It is genetically close to species within the genus Canis, but distinct in several anatomical aspects: its skull is convex rather than concave in profile, it lacks a third lower molar and the upper molars possess only a single cusp as opposed to between two and four. During the Pleistocene, the dhole ranged throughout Asia, with its range also extending into Europe but became restricted to its historical range 12,000–18,000 years ago. It is now extinct in Central Asia, parts of Southeast Asia, and possibly the Korean peninsula and Russia.
Jackals are canids native to Africa and Eurasia. While the word "jackal" has historically been used for many canines of the subtribe canina, 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 Europe and Asia. The African golden wolf was also formerly considered a jackal.
The dire wolf is an extinct canine. 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: Aenocyon dirus guildayi and Aenocyon dirus dirus. The largest collection of its fossils has been obtained from the Rancho La Brea Tar Pits in Los Angeles.
Canis is a genus of the Caninae which includes multiple extant species, such as wolves, dogs, coyotes, and golden 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.
Speothos is a genus of canid found in Central and South America. The genus includes the living bush dog, Speothos venaticus, and an extinct Pleistocene species, Speothos pacivorus. Unusually, the fossil species was identified and named before the extant species was discovered, with the result that the type species of Speothos is S. pacivorus. S. pacivorus had a larger overall body size and a double-rooted second lower molar. It has been proposed that Speothos originated in the Brazilian highlands sometime during the Pleistocene.
The Sardinian dhole is an extinct insular canid which was endemic to what is now the Mediterranean islands of Sardinia and Corsica during the Middle-Late Pleistocene. It went extinct at the end of the Pleistocene around the time of human settlement of the islands.
Caninae ,) is the only living subfamily within Canidae, alongside the extinct Borophaginae and Hesperocyoninae. They first appeared in North America, during the Oligocene around 35 million years ago, subsequently spreading to Asia and elsewhere in the Old World at the end of the Miocene, some 7 million to 8 million years ago.
Armbruster's wolf is an extinct species that was endemic to North America and lived during the Irvingtonian stage of the Pleistocene epoch, spanning from 1.9 Mya—250,000 years BP. It is notable because it is proposed as the ancestor of one of the most famous prehistoric carnivores in North America, the dire wolf, which replaced it.
The African wild dog, also known as the painted dog or 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 distinguished from Canis by dentition highly specialised for a hypercarnivorous diet and by a lack of dewclaws.
Canis edwardii, also known as Edward's wolf, is an extinct species of wolf in the genus Canis which was endemic to North America three million years ago from the Late Blancan stage of the Pliocene epoch and was extinct by the end of the Irvingtonian stage of the Pleistocene epoch.
Eucyon ferox is a species of canid which was endemic to North America and lived during the late Hemphillian age. Originally described as a species of the extant genus Canis, this animal was thought to be an ancestor of the modern day coyote, but recent taxonomic revision has reassigned this species to the extinct genus Eucyon.
Eucyon is an extinct genus of medium omnivorous coyote-like canid that first appeared in the Western United States during the late Middle Miocene 10 million years ago. It was the size of a jackal and weighed around 15kg. Its species E. zhoui was one of a number of North American mammals which invaded East Asia around 5–6 million years ago, followed by the genus going extinct 3 million years ago. This genus is proposed to have given rise to genus Canis 6 million years ago.
Lycaon is a genus of canid which includes the African wild dog and the extinct species Lycaon sekowei and Lycaon magnus.
Lycaon sekowei is an extinct canid species from southern Africa that lived during the early Pleistocene epoch, dating from 2 to 1 million years ago.
The European dhole was a paleosubspecies of the dhole, which ranged throughout much of Western and Central Europe during the Middle and Late Pleistocene. Like the modern Asiatic populations, it was a more progressive form than other prehistoric members of the genus Cuon, having transformed its lower molar tooth into a single cusped slicer. It was virtually indistinguishable from its modern counterpart, save for its greater size, which closely approached that of the gray wolf.
It is widely agreed that the evolutionary lineage of the grey wolf can be traced back 2 million years to the Early Pleistocene species Canis etruscus, and its successor the Middle Pleistocene Canis mosbachensis. 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.
Canis arnensis, is an extinct species of canine that was endemic to Mediterranean Europe during the Early Pleistocene. Canis arnensis has been described as a small jackal-like canid. 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.
Canis etruscus, the Etruscan wolf, is an extinct species of canine that was endemic to Mediterranean Europe during the Early Pleistocene. The Etruscan wolf is described as a small wolf-like dog. It is widely agreed to be the ancestor of Canis mosbachensis, and thus ultimately the modern grey wolf.
Canis mosbachensis is an extinct wolf that inhabited Europe from the late Early Pleistocene to the Middle Pleistocene, around 1.4 million to 400,000 years ago. Canis mosbachensis is widely considered to have descended from the earlier Canis etruscus, and to be the ancestor of the living grey wolf with some considering it as a subspecies of the wolf as Canis lupus mosbachensis. The morphological distinction between C. mosbachensis and C. lupus has historically been vague, and attribution of fossils to C. mosbachensis or to C. lupus around the transition time between the two species is ambiguous.