| Canis mosbachensis | |
|---|---|
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| Skull from Würzburg-Schalksberg | |
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| Life restoration | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Carnivora |
| Family: | Canidae |
| Genus: | Canis |
| Species: | †C. mosbachensis |
| Binomial name | |
| †Canis mosbachensis Soergel, 1925[1] | |
| Subspecies | |
Canis mosbachensis is an extinct wolf that inhabited Europe from the lateEarly Pleistocene to theMiddle Pleistocene, around 1.4 million[3] to 400,000 years ago.[4]Canis mosbachensis is widely considered to have descended from the earlierCanis etruscus, and to be the ancestor of the livinggrey wolf (Canis lupus)[5] with some considering it as a subspecies of the wolf asCanis lupus mosbachensis.[6] The morphological distinction betweenC. mosbachensis andC. lupus has historically been vague, and attribution of fossils toC. mosbachensis or toC. lupus around the transition time between the two species is ambiguous.[4]
Canis mosbachensis was named by Soergel in 1925 based on a collection of remains found at Mosbach, Germany.[1] It was later demonstrated that another canine,Xenocyon lycaonoides was also present at the site, meaning that remains at the site can't be attributed toC. mosbachensis purely based on their canine nature. The lack of atype specimen and the lack of description of some remains from Mosbach has contributed to the ambiguity regarding the circumscription ofC. mosbachensis. Later thorough descriptive work by Sotnikova on material from the late Early Pleistocene site ofUntermassfeld, Germany, provided a more solid basis for the diagnosis ofC. mosbachensis. Later work at other sites revealed the close relationship betweenC. mosbachensis and the modernC. lupus.[4] The mammalogistsErich Tnius,[6]Bjn Kurtén,[7]Henry de Lumley,[8] and Alain Argant[9] have argued thatC. mosbachensis should be considered a subspecies of the grey wolf and assign to it the designationC. lupus mosbachensis. However, other researchers disagree and regardC. mosbachensis as a distinct species.[4]
The Mosbach wolf occurred in the time betweenCanis etruscus in the Early Pleistocene and the modernC. lupus.[10] The phylogenetic descent of the extant wolfC. lupus fromC. etruscus throughC. mosbachensis is widely accepted.[10] However, other researchers cannot see a clearanatomical relationship betweenC. mosbachensis andC. etruscus, thatC. mosbachensis is more similar toC. arnensis,[11][12][13] and that it exhibits a size and dentition more similar to an omnivorous jackal.[13]
In 2010, a study found that the diversity of theCanis group decreased by the end of theEarly Pleistocene toMiddle Pleistocene and was limited inEurasia to two types of wolves. These were the small wolves of theC. mosbachensis–C. variabilis group that were a comparable size to the extantIndian wolf(Canis lupus pallipes), and the largehypercarnivorousCanis (Xenocyon) lycaonoides that was comparable in size to extant northern grey wolves.[14]
As wolves continue to evolve they become bigger. The mammalogist Ronald Nowak proposed thatC. mosbachensis was the ancestor of Eurasian and North American wolves, and that one population ofC. mosbachensis invaded North America where it became isolated by the later glaciation and there gave rise toC. rufus. Another population ofC. mosbachensis remained in Eurasia and evolved intoC. lupus, from where it invaded North America.[10]
The last specimen of the Mosbach wolf in Europe dates to 456–416 thousand years ago,[4] however some specimens were found in southern England that may date toMIS 11—9.[15]
In 2022, Cajus Dietrich proposed the new subspeciesCanis lupus bohemica for remains in the Bat Cave system located nearSrbsko, Central Bohemia, Czech Republic dating to around 800,000 years ago.[15]
Morphological characters distinguishingC. mosbachensis fromC. lupus are ambiguous, and distinguishing the two species is often done based on the body size of specimens (often based on the size of the lowercarnassial tooth), which is not necessarily reliable. Specimens ofC. mosbachensis are smaller than the largest modern populations ofC. lupus, exhibiting a lower range of size variability.[4]
The Zhoukoudian wolfCanis variabilis Pei, 1934 is an extinct small wolf that once inhabited part of what is nowChina andYakutia.Richard H. Tedford comparedC. mosbachensis (which was once distributed from Western Europe to Kazakhstan) withC. variabilis (which was once distributed from Kazakhstan to China) because they both existed in the Middle Pleistocene across mid-latitude Eurasia. The only difference he noted was thatC. variabilis had "nasal bones that terminate at or anterior to the most posterior position of the frontal-maxillary suture", and therefore he proposes these two taxa to represent a variation in the one geographically widespread mid-Pleistocene wolf.[17]
In 2018, a study proposed thatCanis variabilis should be recognized asCanis mosbachensis variabilis, an east Eurasian subspecies of the west EurasianC. mosbachensis. The difference is thatC. m. variabilis possesses a shorter nasal bone and a slight variation in the ridge of the first uppermolar tooth. The craniodental characteristics ofC. m. variabilis are more evolved and indicate that it was less of a hypercarnivore thanCanis chihliensis, the EuropeanC. etruscus andC. arnensis, but was less evolved and less of a hypercarnivore thanC. lupus. It is not a direct ancestor ofC. lupus but was a close relative.[18]
Fossil remains ofC. variabilis have been discovered in centralYakutia in Siberia on theAlaseya River and theAldan River.[19] They are the oldest recorded samples of Olesky era fauna found in Yakutia.[20] Specimens ofCanis cf.variabilis (wherecf. in Latin means confer, uncertain) is thought to have been widespread in Eurasia until around 300,000 years before presentYBP and does not appear to overlap with the earliest occurrence of the morphologically distinctive grey wolf.[16]
Fossils ofC. variabilis were found at theZhoukoudian (once spelt Choukoutien) cave system and archaeological site in 1934 and named by its discoverer,Pei Wenzhong.
Although no sharp line can be traced between the above describedCanis and a trueC. lupus, the marked differences found in size, and in cranial characters, seem to be sufficient for creating, at least, a new variety,Canis lupus variabilis, for the Zhoukoudian Locality 1 small wolf.[2]: 17
The small wolf was initially namedCanis lupus variabilis but was later recognised as a variant ofCanis variabilis (Pei 1934) that was also discovered and named by Pei in the same year.[21] Pei stated that the Nihewan wolves[22] attributed toCanis chihliensis should also be included in this new category.[2]: 18 Canis variabilis was also known fromLantian County inShaanxi Province,[23] so it had a wide range in time and space. At the site, the small wolf's remains were in close proximity toHomo erectus pekinensis orPeking Man, in layers dating back to 500,000-200,000 YBP.
Pei describes this small wolf as exhibiting variation in size and tooth adaptations, stating that its skull differs from the typical wolf in much smaller size (about 175.0 mm total length for a largeC. variabilis specimen), with a more slender muzzle and noticeably reduced or absent sagittal crest. In addition, the lower border of someC. variabilis mandibles is "strongly convex as in the dog".[2]: 15 The one trait aligningC. variabilis with wolves is relatively large carnassial teeth (P1 20.4 – 23.0 mm; M1 22.0 – 24 mm). A later researcher has confirmed Pei's measurements, and describes the wolf's skull as having "heavy, wolf-like proportions although smaller than any extantC. lupus.[24] More recent researchers have revisited Pei's view that the ancestor of the dog is a now extinctCanis lupus, and proposed thatC. variabilis might be an ancestor of the dog lineage.[25][26]: 7
In 2012, a study of the wolf-likeCanis species of ancient China conducted by the noted vertebratepaleontologist and geologistXiaoming Wang found thatC. variabilis was "very strange" compared to otherCanis in China as it had much smaller cranio-dental dimensions than earlier and later species. The study concluded that "It is very likely that this species is the ancestor of the domestic dogCanis familiaris, a hypothesis that has been proposed by previous authors."[2][24][27][28]
In 2015, a study looked at themitochondrial control region sequences of 13 ancient canid remains and one modern wolf from five sites across Arctic north-east Siberia. The fourteen canids revealed nine mitochondrialhaplotypes, three of which were on record and the others not reported before. The phylogentic tree generated from the sequences showed that four of the Siberian canids dated 28,000 YBP and oneCanis c.f. variabilis dated 360,000 YBP were highly divergent. The haplotype designated as S805 (28,000 YBP) from theYana River was one mutation away from another haplotype S902 (8,000 YBP) that represents Clade A of the modern wolf and domestic dog lineages. Closely related to this haplotype was one that was found in the recently-extinctJapanese wolf. Several ancient haplotypes were oriented around S805, includingCanis c.f. variabilis (360,000 YBP), Belgium (36,000 YBP – the "Goyet dog"), Belgium (30,000 YBP), and Konsteki, Russia (22,000 YBP). Given the position of the S805 haplotype on the phylogenetic tree, it may potentially represent a direct link from theprogenitor (includingCanis c.f. variabilis) to the domestic dog and modern wolf lineages. The grey wolf is thought to be ancestral to the domestic dog, however its relationship toC. variabilis, and the genetic contribution ofC. variabilis to the dog, is the subject of debate.[16]
TheZhokhov Island (8,700 YBP) and Aachim (1,700 YBP) canid haplotypes fell within the domestic dog clade, cluster with S805, and also share their haplotypes with – or are one mutation away from – theTibetan wolf (C. l. chanco) and the recently-extinctJapanese wolf (C. l. hodophilax). This may indicate that these canids retained the genetic signature of admixture with regional wolf populations. Another haplotype designated as S504 (47,000 YBP) fromDuvanny Yar appeared on the phylogenetic tree as not being connected to wolves (both ancient and modern) yet ancestral to dogs, and may represent a genetic source for regional dogs.[16] The authors concluded that the structure of the modern doggene pool was contributed to from ancient Siberian wolves and possibly fromCanis c.f. variabilis.[29]
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