| Homo longi | |
|---|---|
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| HBSM2018-000018(A)cranium | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Primates |
| Suborder: | Haplorhini |
| Infraorder: | Simiiformes |
| Family: | Hominidae |
| Subfamily: | Homininae |
| Tribe: | Hominini |
| Genus: | Homo |
| Species: | †H. longi |
| Binomial name | |
| †Homo longi Jiet al., 2021 | |
Homo longi is an extinctspecies ofarchaic human identified from a nearly complete skull, nicknamed 'Dragon Man', fromHarbin on theNortheast China Plain, dating to at minimum 146,000 years ago during theMiddle Pleistocene. The skull was discovered in 1933 along theSonghua River while theDongjiang Bridge [zh] was under construction for theManchukuo National Railway. Due to a tumultuous wartime atmosphere, it was hidden and only brought topaleoanthropologists in 2018.H. longi has been hypothesized to be the same species as theDenisovans, but this has not been confirmed.
H. longi is broadly anatomically similar to other Middle Pleistocene Chinese specimens. Like other archaic humans, the skull is low and long, with massively developed brow ridges, wideeye sockets, and a large mouth. The skull is the longest ever found from any human species. Like modern humans, the face is rather flat, but with a larger nose. The brain volume was 1,420 cc, within the range of modern humans and Neanderthals.
The specific name forH. longi is derived from the geographic nameLongjiang (literally "Dragon River"), a term commonly used for the Chinese provinceHeilongjiang.[2]
In 1933, a local laborer found a nearly complete skull at the riverbank ofSonghua River, when he was building theDongjiang Bridge [zh] inHarbin (at the time part ofManchukuo) for the Japanese-alignedManchukuo National Railway. Recognizing its importance, likely as a result of public interest in anthropology that had recently been generated by thePeking Man in 1929, just four years before, he hid it from the Manchukuo authorities in an abandoned well.[1]
In 1945, upon theSoviet invasion of Manchuria that ended theJapanese occupation of the region, he concealed his former employment fromthe Nationalist and laterthe Communist authorities. Consequently, he could not report the skull, lest he divulge his ties to the Japanese imperialists in explaining its origin.[1]
In 2018, before his death, the third generation of his family learned of the skull, and reclaimed it. Later that year, Chinesepaleoanthropologist Ji Qiang persuaded the family to donate it to theHebei GEO University for study, where it has since been stored. Its catalogue number is HBSM2018-000018(A).[1]
Owing to the skull's history, its exactprovenance, and thus itsstratigraphic context and age, has been difficult to determine.[3][4]
In 2021, Chinese geologist Shao Qingfeng and colleagues performed non-destructivex-ray fluorescence,rare-earth element, andstrontium isotope analyses on the skull and various other mammalian fossils unearthed around Dongjiang Bridge, and determined that all the fossils from the vicinity were likely deposited at around the same time, lived in the same region, and probably originate from the UpperHuangshan Formation, dating to 309 to 138 thousand years ago.[3]
Directuranium–thorium dating of various points on the skull yielded a wide range of dates, from 296 to 62 thousand years ago, likely a result ofuraniumleaching. They statistically determined the most likely minimum age is 146,000 years old, but a more exact value is difficult to determine, given that the exact provenance is unidentifiable. Nonetheless, the skull is well-constrained to the lateMiddle Pleistocene, roughly contemporaneous with other Chinese specimens fromXiahe,Jinniushan,Dali, andHualong Cave.[3]
| A proposed recent human family tree |
| According to Niet al. 2021[1] (note,Xiahe andDenisovans are most closely related toNeanderthals according tonDNA andancient protein analyses.[5]) |
In two simultaneously published papers, Ji and colleagues declared the Harbin skull to represent a new species they dubbedHomo longi. The Harbin skull is quite similar to the Dali skull, and when the Dali skull was discovered in 1978, it was given a new nomenH. sapiens daliensis by its discoverer Wu Xinzhi who soon thereafter abandoned the name. Consequently, should the Middle Pleistocene Asian humans represent a single unique species, the nomenH. daliensis might takepriority. Though they recommended resurrectingH. daliensis, they arguedH. longi is sufficiently distinct, and allocated only the Dali andHualong remains (often allocated toH. heidelbergensis by convention) toH. daliensis; thus, they claim at least two human species inhabited late Middle Pleistocene China.[2] One of the authors,Chris Stringer, stated that he would have preferred assigning the Harbin skull toH. daliensis.[6] However, according to a more recent assessment (including among its authors Xijun Ni, one of the describers of the speciesH. longi), since Wu wrote only that "it is suggested that Dali craniumprobably represents a new subspecies" (p. 538, italics added for emphasis) the namedaliensis was never validly published according toInternational Commission on Zoological Nomenclature (ICZN) rules, being proposed conditionally and published after 1960 (and not formally proposed by subsequent workers in the intervening period), and is therefore unavailable and thus could not compete withlongi for priority.[7]
Based on the conspicuously massive size of the molars, they suggestedH. longi is most closely related to and possibly the same species as the Xiahe mandible fromTibet,[2] which has been grouped with the enigmaticDenisovans, anarchaic human lineage apparently dispersed across East Asia during the Middle and Late Pleistocene currently identifiable from only a genetic signature. The Xiahe mandible is also anatomically similar to specimens fromXujiayao andPenghu.[5] Ji, Ni and colleagues further contend that Middle Pleistocene Asian specimens are more closely related to modern humans (H. sapiens) than the EuropeanNeanderthals,[2][1] thoughnuclear DNA andancient protein analyses place the Xiahe mandible and Denisovans more closely to Neanderthals than to modern humans.[5][8]
H. longi is characterized by a low and long skull, receding forehead, extremely wide upper face, a large nasal opening equating to an enlarged nose (possibly an adaptation to the cold air), large and squareeye sockets, inflated and thickbrow ridges (supraorbital torus), flat cheekbones (zygomatic bone), a widepalate and large tooth sockets (equating to a large mouth), and a broadbase of the skull.[2] The Harbin skull measures 221.3 mm × 164.1 mm (8.7 in × 6.5 in) in maximum length x breadth, with anaso-occipital length of 212.9 mm (8.4 in), making it the longest archaic human skull to date.[1] For comparison, the dimensions of a modern human skull average 176 mm × 145 mm (6.9 in × 5.7 in) for men and 171 mm × 140 mm (6.7 in × 5.5 in) for women.[9] The Harbin skull also has the longest brow ridge at 145.7 mm (5.74 in).[1]
H. longi had a massive brain at roughly 1,420 cc, above the range of all known human species except modern humans and Neanderthals. Nonetheless,post-orbital constriction (a constriction of the braincase just behind the eyes, absent in modern humans, and equating to the location of thefrontal lobes) is more developed inH. longi than in Neanderthals, although not so much as in more-ancient human species.[2] Overall, thebraincase retains an array of archaic features, though the occipital bone at the back of the skull has a weakly-definedsagittal keel that lacks a protuberance at the midpoint, unlike most other archaic humans. Unlike the Dali and Hualong Cave skulls, the keel does not run across the midline. Unlike modern humans or Neanderthals, theparietal bones on the top of the head do not significantly expand or protrude.[1]
Despite the face being so wide, it was rather flat (reduced mid-facialprognathism), and resembles the anatomy found in modern humans, the far more ancientH. antecessor, and other Middle Pleistocene Chinese specimens. Nonetheless, the tooth sockets for the incisors were angled outward (alveolar prognathism). TheH. longi skull's mosaic morphology of archaic and derived traits converges with some of the earliest specimens assigned toH. sapiens from Africa, notably Rabat[10] andEliye Springs. Because the original describers judged the Harbin skull to be closely allied with the Xiahe mandible, they believedH. longi lacked a chin, like other archaic humans, but the specimen's lower jaw was not recovered.[1] The only preserved tooth, the upper left second molar, is enormous, with a length x breadth (mesiodistal x labiolingual) of 13.6 mm × 16.6 mm (0.54 in × 0.65 in), comparable to the Denisovan molar recovered fromDenisova Cave. The Harbin molar is oval-shaped, badly worn, and nearly flat.[1] In contrast, the average dimensions of a sample of 40 modern human male molars were 10.2 mm × 11.8 mm (0.40 in × 0.46 in).[11]
Ni and colleagues believed the Harbin skull represents a male, judging by the robustness and size of the skull, who was less than 50 years old, looking at thesuture closures and the degree of tooth wearing. They speculatedH. longi had perhaps medium-dark to medium-light skin, dark hair, and dark eye color based on reconstructed genetic sequences from Neanderthals, Denisovans, and early modern humans.[1]
The left parietal features shallow indents around thebregma, possibly from a healed injury. The second left upper molar does not appear to have been in contact with the third molar, which means either that the third molar was small (creating agap), or it was absent in this individual.[1]
Middle-Late Pleistocene sediments around Harbin from which the skull is thought to originate also contain the remains of the giant deerSinomegaceros ordosianus,wild horse,elk/wapiti, the buffaloBubalus wansijocki,brown bear,[3](see supplemental material)tigers,cave lions,woolly mammoth andwoolly rhinoceros.[12]
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