Dingo (taxon)

Taxonomy

In 1758, the taxonomist Linnaeus published in his Systema Naturae the taxonomic classification of species. Canis is a Latin word meaning dog, and under this genus he listed the dog-like carnivores including domestic dogs, wolves, and jackals. He classified the domestic dog as Canis familiaris (Linnaeus, 1758) and on the next page as a separate species he classified the wolf as Canis lupus (Linnaeus, 1758). In 1926, the International Commission on Zoological Nomenclature (ICZN) ruled in Opinion 91 that the domestic dog Canis familiaris (Linnaeus, 1758) be placed on its official list. In 1957, the ICZN ruled in Opinion 451 that Canis dingo (Meyer, 1793) was the name to be used for the dingo and that this be placed on its official list. These are the scientific names for the dog and dingo that appear on the Official Lists and Indexes of Names in Zoology of the ICZN.

In 1978, a review to reduce the number species listed under genus Canis proposed that "Canis dingo is now generally regarded as a distinctive feral domestic dog. Canis familiaris is used for domestic dogs, although taxonomically it should probably be synonymous with Canis lupus." In 1982, the first edition of Mammal Species of the World included a note under Canis lupus with the comment: "Probably ancestor of and conspecific with the domestic dog, familiaris. Canis familiaris has page priority over Canis lupus, but both were published simultaneously in Linnaeus (1758), and Canis lupus has been universally used for this species". In the same year, an application was made to the ICZN to reclassify the dingo to Canis lupus dingo because it was proposed that the wolf (Canis lupus) was the ancestor of dogs and dingoes, however the application was rejected.

In 2003, the ICZN ruled in its Opinion 2027 that the "name of a wild species...is not invalid by virtue of being predated by the name based on a domestic form." Additionally, the ICZN placed the taxon Canis lupus as a conserved name on the official list under this opinion. In the third edition of Mammal Species of the World published in 2005, the mammalogist W. Christopher Wozencraft listed under the wolf Canis lupus what he proposed to be two subspecies: "familiaris Linneaus, 1758 [domestic dog]" and "dingo Meyer, 1793 [domestic dog]", with the comment "Includes the domestic dog as a subspecies, with the dingo provisionally separate – artificial variants created by domestication and selective breeding. Although this may stretch the subspecies concept, it retains the correct allocation of synonyms." Although the earliest use of the name "dingo" was Canis familiaris dingo (Blumenbach, 1780), Wozencraft attributed it to Meyer from 1793 without comment.

This classification by Wozencraft is hotly debated by zoologists. Mathew Crowther, Stephen Jackson and Colin Groves disagree with Wozencraft and argue that based on ICZN Opinion 2027, the implication is that a domestic animal cannot be a subspecies. Crowther, Juliet Clutton-Brock and others argue that because the dingo differs from wolves by behavior, morphology, and that the dingo and dog do not fall genetically within any extant wolf clade, that the dingo should be considered the distinct taxon Canis dingo. Jackson and Groves regard the dog Canis familiaris as a taxonomic synonym for the wolf Canis lupus with them both equally ranked at the species level. They also disagree with Crowther, based on the overlap between dogs and dingoes in their morphology, in their ability to easily hybridize with each other, and that they show the signs of domestication by both having a cranium of smaller capacity than their progenitor, the wolf. Given that Canis familiaris (Linnaeus, 1758) has date priority over Canis dingo (Meyer, 1793), they regard the dingo as a junior taxonomic synonym for the dog Canis familiaris. Gheorghe Benga and others support the dingo as a subspecies of the dog from the earlier Canis familiaris dingo (Blumenbach, 1780).

Taxonomic synonyms

A taxonomic synonym is a name that applies to a taxon that now goes by a different name. In the third edition of Mammal Species of the World published in 2005, the mammalogist W. Christopher Wozencraft listed the following taxonomic synonyms with the taxon dingo under the classification Canis lupus dingo:

dingo Meyer, 1793 [domestic dog]; antarticus Kerr, 1792 [suppressed, ICZN, O.451]; australasiae Desmarest, 1820; australiae Gray, 1826; dingoides Matschie, 1915; macdonnellensis Matschie, 1915; novaehollandiae Voigt, 1831; papuensis Ramsay, 1879; tenggerana Kohlbrugge, 1896; hallstromi Troughton, 1957; harappensis Prashad, 1936.

Of these ten taxa, the majority refers to the Australian dingo, one to the New Guinea Singing Dog, and 3 that refer to dogs that were once found in the Indonesian archipelago or Southern Asia.

"dingo", Australian dingo

For Canis dingo, the following taxa are regarded as taxonomic synonyms: antarticus [suppressed], Canis familiaris australasiae, Canis australiae, Canis dingoides, Canis macdonnellensis, Canis familiaris novaehollandiae.

In 1768, James Cook took command of a scientific voyage of discovery from Britain to New Holland, which was the name for Australia at that time. In 1770, his ship HMS Endeavour arrived in Botany Bay, which is now part of Sydney. The mission collected specimens and made notes for taking back to Britain. On return to Britain, Joseph Banks commissioned George Stubbs to produce paintings based on his observations, one of which was the "Portrait of a Large Dog from New Holland" completed in 1772. Johann Friedrich Blumenbach gathered together a collection from the Cook voyage and was the first to classify the "New Holland dog" as Canis familiaris dingo (Blumenbach, 1780).

In 1788, the First Fleet arrived in Botany Bay under the command of Australia's first colonial governor, Arthur Phillip, who made a brief description and an illustration in his journal of the "Dog of New South Wales". In 1793, the "Dog of New South Wales" was classified by Friedrich Meyer as Canis dingo (Meyer, 1793), based on the illustration. In 1947, a proposal was made to change this classification after it was discovered that the "New Holland dog" Canis antarticus (Kerr, 1792) had been specified a year earlier in a little-known work. Both Kerr and Meyer had based their classifications on the illustration of the "Dog of New South Wales", and therefore there is no reference specimen that these were based on. In 1957, the International Commission on Zoological Nomenclature (ICZN) was asked to suppress the name Canis antarticus on the grounds that Canis dingo was the common name that had been used for over 150 years. The ICZN ruled in favour of Canis dingo (Meyer, 1793) and suppressed the name Canis antarticus (Kerr, 1792) in its Opinion 451.

The taxonomic classification of the dingo remains both confused and debated. Whether the dingo was a wild or domesticated species was not clarified from Meyer's original description, which translated from the German language ambiguously reads:

It is not known if it is the only dog species in New South Wales, and if it can also still be found in the wild state; however, so far it appears to have lost little of its wild condition; moreover, no divergent varieties have been discovered.

"hallstromi", New Guinea singing dog

Janice Koler-Matznick and others disagree with Wozencraft, and believe that "Canis hallstromi" (New Guinea Singing Dog) should not be classified under Canis lupus dingo on the grounds that it has behavioral, morphological and molecular characteristics that are distinct from the wolf.

"harappensis", ancient dog found in South Asia

During excavation seasons in 1924-25 and 1930–31, a team of researchers at Harappa, in modern Pakistan, collected a wide variety of ancient domestic animal remains which had been buried since three thousand years BC. The remains included a dog whose skull morphology was described as being very similar to Canis tenggerana from Java. It had earlier been proposed that a population of early dogs had been more widespread across the region, and therefore the specimen was described as Canis tenggerana harappensis. Jackson and Groves disagree with Wozencraft, and believe that this taxon does not closely resemble the dingo.

"tenggerana", Java

In the late nineteenth century, naturalists working in the Tennger Mountains in Eastern Java identified a dog which they named "Canis familiaris tenggerana" after the local people called the Tenggerese. A similar dog existed in the Dieng highlands, and it is assumed that pure populations of these two dogs no longer exist, mainly as a result of cross-breeding with varieties of domestic dogs. The status of the Tengger as being wild or domesticated is not clear. It has been described as a bush-dwelling dog although its morphology shows no wild adaption, and it has also been described as easy to domesticate. Jackson and Groves disagree with Wozencraft, and believe that this taxon does not closely resemble the dingo.

"papuensis", Papua New Guinea

In a report to the Linnean Society of New South Wales in 1882, N. De Miklouho-Maclay identified several anatomical and behavioural differences between Australian Dingoes and dogs that inhabited the coastal lowlands (Maclay Coast) of Papua New Guinea. He gave the Papuan coastal canines the scientific name Canis papuensis. The differences between Canis dingo and Canis papuensis included a much smaller brain, which he attributed to the quite different lifestyles of the two animals. There were several differences in overall looks and build. Whereas the Australian Dingo is well known for its intelligence and boldness, as well as near independence from humans, he reported that the coastal Papuan canines remained on the periphery of native villages, regularly feeding on cast-offs and human waste. Hunting on their own was almost unknown. Instead of the bold independence of the Australian dingo, the coastal dogs behaved very subserviently toward humans, exhibiting begging and grovelling. Additionally, he stated, "The Canis papuensis is very different in appearance and character from Canis dingo; is generally smaller, has not the bushy tail of the dingo...." Jackson and Groves propose that papuensis may refer to feral dogs.

Lineage

The archaeological record shows that the earliest dingo skeletal remains in Australia date to 3,450 years before present (YBP) from the Mandurah Caves on the Nullabor Plain, south-eastern Western Australia; 3,320 years YBP from Woombah Midden near Woombah, New South Wales; and 3,170 years YBP from Fromme's Landing on the Murray River near Mannum, South Australia. There are doubts about the proposed 8,000 YBP for other remains due to problems with their stratigraphic interpretation. How dingos arrived in Australia remains unknown. The earliest dingo remains in the Torres Straits date to 2,100 YBP. In New Guinea, the earliest dog bones date to 2,500–2,300 YBP from Caution Bay near Port Moresby but no ancient New Guinea Singing Dog remains have been found.

At the end of the Last glacial maximum and the rise in sea levels, Tasmania became separated from the Australian mainland 12,000 YBP, and New Guinea 8,500 YBP by the inundation of the Sahul Shelf. No remains have been uncovered in Tasmania, therefore the Dingo is estimated to have arrived in Australia between 3,500-12,000 YBP. To reach Australia through the Malay Archipelago even at the lowest sea level of the Last Glacial Maximum, a journey of at least 50 km over open sea was necessary, indicating that the dingo arrived by boat. Studies of the dingo maternal lineage through the use of Mitochondrial DNA (mDNA) as a genetic marker indicate that dingoes are descended from a small founding population through a single founding event or no more than a few founding events either 4,600-5,400 YBP or 4,600-10,800 YPB, or 4,640-18,300 YBP, depending on mutation rate assumptions used. They remained isolated from other dogs until the arrival of Europeans.

Ancestors

In 1995, a researcher compared the skull morphology of the dingo to those of other dogs and wolves and concluded that the dingo was a primitive dog that may have evolved from the Indian wolf (C. l. pallipes) or the Arabian wolf (C. l. arabs). Based on phenotype, the same researcher thought that dingoes were widespread across the planet in the past but had declined due to admixture with domestic dogs. They were thought to exist in Australia as wild dogs, rare in New Guinea, but common in Sulawesi and in northern and central Thailand. Relic populations were thought to occur in Cambodia, China, India, Indonesia, Lao PDR, Malaysia, Myanmar, Papua New Guinea, Philippines and Viet Nam. However, morphological comparisons (based on skull measurements) had not been undertaken on specimens to provide a better understanding. Later DNA studies indicate this proposed wide distribution to be incorrect.

Early DNA studies indicated that the dingo was more closely related to the domestic dog than it was to the wolf or the coyote.

A haplotype (haploid genotype) is a group of genes in an organism that are inherited together from a single parent. In 2004, a study looked at the maternal mDNA of the Australian dingo. All dingo sequences in the study were found to be either identical to, or differing by a single substitution from, a single mDNA haplotype named A29. All dingo sequences since studied exhibit haplotype A29, which falls within the Clade A haplogroup that represents 70% of domestic dogs. In 2009, a study further categorised haplotype A29 within the a2 sub-haplogroup that originated from hybridization between dog and wolf post-domestication. Later studies analysed the whole genome of a dingo provided significant evidence of admixture between the dingo and a Chinese wolf. The dingo lineage derives from dog/Chinese wolf genetic admixture.

Haplotype A29 is found in both Australian dingoes and in domestic dogs exclusively in the East Asian region: East Siberia, Arctic America, Japan, Indonesia, New Guinea and in South China, Kalimantan, and Bali. It is associated with the Siberian Husky and the American Arctic breeds, the Alaskan Malamute, Alaskan Husky, Greenland dog and the Canadian Eskimo Dog. The evidence suggests that the haplotype was introduced from East Asia or southeast Asia through the islands of the Malay Archipelago and into Australia. Haplotype A29 was one of several domestic dog mDNA haplotypes brought into the Malay Archipelago but only A29 reached mainland Australia.

Sister

In 2011, a study looked at the mDNA of the Australian dingo and the New Guinea Singing Dog. The mDNA haplotype A29, or a haplotype one step away, was found in all of the Australian dingoes and New Guinea Singing Dogs studied, indicating a common female ancestry.

In 2012, a study looked at the dingo male lineage using Y chromosome DNA (yDNA) as a genetic marker and found 2 yDNA haplotypes. Haplotype H3 could be found in domestic dogs in East Asia and Northern Europe. Haplotype H60 had not been previously reported but was one step away from haplotype H5 that could be found in East Asian domestic dogs. Only the New Guinea Singing Dog and dingoes from north-eastern Australia showed haplotype H60, which implies a genetic relationship and that the dingo reached Australia from New Guinea. Haplotype H60 and H3 could be found among the southern Australian dingoes with H3 dominant, but haplotype H3 could only be found in the west of the continent and may represent a separate entry from the northwest. Earlier studies using other genetic markers had found the indigenous Bali dog more closely aligned with the Australian dingo than to those European and Asian breeds selected for comparison which indicated that the Bali dog was genetically diverse with a diverse history, however only one percent exhibited the A29 mDNA haplotype.

Cousins

mDNA (maternal)

In 2011, a study looked at 582 mDNA base-pairs of the mtDNA control region of dogs from the Malay Peninsula and found that the two most common dog haplotypes of the Indonesian region, in particular Bali and Kalimantan, was mDNA haplotype A75 (40%) and "the dingo founder haplotype" A29 (8%). Also present were haplotypes A120 and A145. All 4 haplotypes fall within the a2 mDNA sub-haplogroup. The study also looked at archaeological specimens of ancient Polynesian dogs from which only a " short-haplotype" (263 mDNA base pairs - nucleotide positions 15,458-15,720) could be derived. This short haplotype was named Arc2 and corresponds to mDNA haplotypes A75 and A120, and it could be found in 70% of samples found as far away as Hawaii and New Zealand. No dogs from Taiwan nor the Philippines carried the dingo or Polynesian haplotypes, which indicates that dogs did not enter the Pacific from a north-eastern route.

In 2015, a study looked at the mDNA taken from ancient dog samples discovered at an archaeological site at Wairau Bar, New Zealand and found that the sequences corresponded to the a2 mDNA sub-haplogroup. The dog samples all carried the mDNA haplotype A192, which has only been reported in some modern village dogs from Bali, Indonesia. When compared with the two ancient Polynesian haplotypes Arc1 and Arc2, all of the Wairau Bar dogs matched Arc2. Dogs from Wairau Bar likely represent part of the initial population of dogs introduced to New Zealand, having arrived with people around the beginning of the fourteenth century.

All of these dogs carry haplotypes that fall under the mDNA a2 sub-haplogroup and are therefore descendents of a dog/Chinese wolf hybrid ancestor. In 2015 the most comprehensive study of mDNA haplotypes to date found that the a2 sub-haplogroup represents 3% of all dogs in South East Asia, 22% in the Indian subcontinent and 16% in East Asia.

yDNA (paternal)
In 2013, a study conducted a yDNA analysis of 338 Australian dingoes, New Guinea Singing Dogs, and village dogs from Island Southeast Asia. The Bali dogs support the arrival of their ancestors with the Austronesian expansion and the arrival of other domesticates 3-4,500 YBP. The data confirms that dingoes carry the unique yDNA haplogroup (H60) and it has been derived from yDNA haplogroup H5. Haplogroup H5 was not found in the village dogs from Island Southeast Asia but it is common in Taiwan. One H5 specimen from Taiwan clustered with one H60 from Australia with the indication of a common ancestor 4-5,000 YBP and coincides with the expansion of the Daic people of Southern China. The conclusion is that there were 2 expansions of two types of dogs. Southern China produced the first ancient regional breeds 8,000 years ago. These were then dominated and replaced by a later explosive expansion of genetically diverse dogs that had been bred in South East Asia. If so, the dingo and the New Guinea Singing Dog, that pre-date the dogs of Island Southeast Asia, would reflect the last vestiges of the earlier ancient breeds.

Whole genome sequences

Whole genome sequencing has been used to survey "...the supposedly ancient, semi-domestic dog breeds, the Basenji and dingo." In 2016, a study based on whole-genome sequences indicated that the dog is a genetically divergent subspecies of the gray wolf and was derived from a now-extinct ghost population of Late Pleistocene wolves, the dog and the dingo were not separate species, and in accordance with previous studies that the dingo and the Basenji are considered to be basal members of the domestic dog clade. "The term basal taxon refers to a lineage that diverges early in the history of the group and lies on a branch that originates near the common ancestor of the group." The study found that some dog breeds, including the dingo and basenji, were almost as genetically divergent from other dogs as the dog is from the wolf, and that their ancestral lineages had diverged from other dogs 8,500 years ago (or 23,000 years ago using another method). The study found less than 3 percent admixture (in both directions) between the ancestral lineage of the dingo and those of Asian wolves.