\u201cThat\u2019s a big change,\u201d said Chris Stringer, a paleoanthropologist at the Natural History Museum in London and co-author of the study. <\/p>\n
\u201cWe\u2019re talking about something maybe double that for the divergence of those groups.\u201d<\/p>\n
But other researchers remain unswayed by the new assessment of the skull, first unearthed in 1990. <\/p>\n
The weight of evidence from genetic analysis and other fossils, they say, suggests a much more recent origin for our species, Homo sapiens.<\/p>\n
\u201cI am afraid that I remain unconvinced by the dates suggested,\u201d said Marta Miraz\u00f3n Lahr, a Cambridge archaeology professor who was not involved in the study.<\/p>\n
The cranium in question is one of several dug up at an archaeological site along the banks of the Han River, a tributary of the Yangtze, in central China. Other research has dated the site at about a million years old.<\/p>\n
Scientists were keen to examine the skulls and place them on the tree of human evolution. <\/p>\n
The first of the skulls, found in 1989, was badly crushed by sediment, as if a steamroller had smashed it from the eyebrow to the back of the head. The second, discovered the following year and dubbed \u201cYunxian 2,\u201d wasn\u2019t in much better shape.<\/p>\n
For a while, palaeontologists speculated that the skulls belonged to one of the earliest lineages on the tree of human evolution, Homo erectus. When paleoanthropologist Xijun Ni got his hands on Yunxian 2 several years ago, he assessed that it was too large for that.<\/p>\n
\u201cWhen I had a chance for the first time to hold the specimen, I suddenly realised it\u2019s so big,\u201d said Ni, a Chinese Academy of Sciences researcher who co-wrote the study.<\/p>\n
With skull in hand, Ni, Stringer and their colleagues painstakingly put its shattered pieces back together like a jigsaw puzzle \u2013 at least digitally, after giving the fossil a CT scan and reconstructing the cranium in a computer program. To fill in missing pieces, the researchers incorporated some anatomical elements from the first skull, called Yunxian 1.<\/p>\n
\u201cThere were so many cracks and broken pieces,\u201d Ni said. \u201cIt\u2019s very much like a digital surgery.\u201d<\/p>\n
Eric Delson, a paleoanthropologist at the American Museum of Natural History in New York who was not involved in the study, called the reconstruction of the skull \u201cfantastic\u201d, especially when \u201ccompared to the squashed pancake it was before\u201d.<\/p>\n
\u201cThis paper is a really important contribution,\u201d said Suzy White, a paleoanthropologist at the University of Reading in Britain not involved in the study. <\/p>\n
\u201cThis fossil has been difficult to interpret due to its distorted appearance.\u201d<\/p>\n
The digitally restored skull revealed a mix of primitive and modern traits. The skull is low and long, like the oldest members of the Homo genus, but the brain it contained must have been big, like in modern humans. <\/p>\n
The researchers concluded that it belonged to a group of early humans dubbed the longi clade, which likely includes a group called the Denisovans.<\/p>\n
Given the understanding that the site where the skulls were unearthed is about a million years old, the team used that date as a reference point to refashion the tree of life describing human evolution. <\/p>\n
The team concluded that the longi clade branched from the lineage of modern humans about 1.32 million years ago while Neanderthals diverged 1.38 million years ago.<\/p>\n
Lahr said the best genomic evidence suggests that Neanderthals and Denisovans are actually more closely related to one another than they are to modern humans, in conflict with how the newly proposed tree branches.<\/p>\n
And the consensus view from geneticists is that our species is a relative newcomer, branching off only 500,000 to 700,000 years ago. Neanderthals and Denisovans are so closely related to modern humans that the three groups once interbred with each other.<\/p>\n
Svante Paabo, a geneticist at the Max Planck Institute for Evolutionary Anthropology who won a Nobel Prize for discovering sexual intermingling between ancient human species, said only the retrieval of DNA, or perhaps proteins, will resolve the skull\u2019s relationship with the rest of humanity.<\/p>\n
Paabo added that there is not \u201cenough information from the morphology of these specimens to confidently determine how they are related to each other, much less date the divergences between them\u201d.<\/p>\n
Stringer and Ni said the skull is too old to retain DNA. And they acknowledged that, without more fossils, it is impossible to know if their reconstruction is perfect. They hope a third skull, found in 2022 at the same site, can shed more light.<\/p>\n
\u201cSome researchers may be sceptical of these relatively deep divergence dates,\u201d Stringer said. \u201cBut if Yunxian is indeed an early member of the longi-Denisovan clade, this necessarily pushes back the minimum age of that clade to at least one million years.\u201d<\/p>\n
Sign up to Herald Premium Editor\u2019s Picks<\/a>, delivered straight to your inbox every Friday. Editor-in-Chief Murray Kirkness picks the week\u2019s best features, interviews and investigations. Sign up for Herald Premium here<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"\u201cThat\u2019s a big change,\u201d said Chris Stringer, a paleoanthropologist at the Natural History Museum in London and co-author…\n","protected":false},"author":2,"featured_media":43519,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[24752,2196,1975,1853,9084,607,38708,6567,38709,16420,24176,1357,13457,117,111,139,69,1118,147,34516,2742,38707,1865,6923,1530],"class_list":["post-43518","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-ago","tag-ancient","tag-at","tag-central","tag-challenges","tag-china","tag-eking","tag-evolution","tag-existence","tag-human","tag-hundreds","tag-lived","tag-look","tag-new","tag-new-zealand","tag-newzealand","tag-nz","tag-of","tag-science","tag-skull","tag-thousands","tag-timeline","tag-today","tag-what","tag-years"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/43518","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/comments?post=43518"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/43518\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media\/43519"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media?parent=43518"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/categories?post=43518"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/tags?post=43518"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}