Seventeen skull unearthed in a Middle Pleistocene cave in Spain showcase a mix of trait : some Neanderthal features , some more primitive ones . Thefindingssuggest that Neanderthals evolved their define characteristics in stagecoach , rather than all at once – start with their face and teeth betimes on .
About 500,000 years ago , a group of ancientHomosplit off from others populate in Africa and East Asia , eventually settling in Eurasia . Once there , their population evolve characteristics that would later define the Neanderthals . Several hundred thousand old age later , modern humans ( who uprise in Africa ) also conciliate in Eurasia . The details of this time remain controversial , though ultimately , modern humans replaced Neanderthals by around 30,000 old age ago .
" What I have been telling citizenry is that it was like Game of Thrones,“saysJuan - Luis Arsuaga ofJoint Center UCM - ISCIII Evolution and Human Behaviorin Madrid . " There were a few spreading - out populations , some related to , some not , emigrate or decease extinct over clock time . And wintertime was always derive . "
excavate from a deep stone pit of pearl at the Sima de los Huesos site in Atapuerca , Spain , these 17 entire skulls – including seven freshly described specimens – belong to a undivided specie dating back 430,000 years ago . They appear to have Neanderthal cheek and teeth , but everything else was relate with primitive human ancestors ( such asHomo heidelbergensis ) , include a minuscule brainpan .
But the fossils do n’t go to a rough-cut ancestor of theirs : They ’re too unseasoned to beH. heidelbergensis , and they ’re far too Neanderthal - like . And although Arsuaga and colleagues have n’t depute them to a particular species yet , they conclude that these fossil are the oldest reliably date proto - Neanderthals .
The Sima universe appears to have been part of an other European lineage that includes Neandertal man , but is more primitive than the later Pleistocene variety that we ’re more familiar with . " We think based on the morphology that the Sima people were part of the Neanderthal clade , " Arsuaga says in anews release , " although not necessarily direct ancestors to the classic Neanderthals . " And definitely not an ancestor of ours .
adjudicate from these skulls , facial modification was the first step in Neanderthal evolution . Their trademark feature film – thick brow ridge with a double archway , robust lower jaw , small molars at the keister , and distinguishable teeth cusp patterns – took embodiment first , then their other defining feature film came along later . Classic Neanderthals had braincases as magnanimous as , and sometimes bigger than , humans .
It ’s of import to note that the Neanderthal - infer lineament were related to chewing . " It seems these alteration had to do with an intensive usance of the frontal teeth,“Arsuaga explains . " The incisors show a keen wear as if they had been used as a ‘ third mitt , ’ typical of Neanderthals . " They may grip objective ( like meat ) with their teeth , allowing them to utilize one free handwriting to becalm the object and the other to cut it with a tool .
The findings point to a mosaic pattern of evolution , with dissimilar features evolving separately at different rates . The " Neanderthalization " process was more of an accretion , rather than a single linear sweep .
researcher have been explore the 12 - cadence pit since the seventies . With thousands of os belong to at least 28 mortal , it ’s the big trove of hominin fossils ever .
Theworkwas publishedSciencethis week .
[ AAASviaScience , New Scientist ]
Images : Javier Trueba / Madrid Scientific Films
