An­cient hu­man an­ces­tor was one tall dude, foot­prints say ‘Re­searchers name the new crea­ture S1’

Kuwait Times - - HEALTH & SCIENCE -

NEW YORK:

He stood a ma­jes­tic 5-foot-5, weighed around 100 pounds and maybe had a harem. That’s what sci­en­tists figure from the foot­prints he left be­hind some 3.7 mil­lion year ago. He’s ev­i­dently the tallest known mem­ber of the pre-hu­man species best known for the fos­sil skele­ton nick­named “Lucy,” reach­ing a stature no other mem­ber of our fam­ily tree matched for an­other 1.5 mil­lion years, the re­searchers say. The 13 foot­prints are im­pres­sions left in vol­canic ash that later hard­ened into rock, ex­ca­vated last year in north­ern Tan­za­nia in Africa.

Their com­par­a­tively large size, av­er­ag­ing a bit over 10 inches long (26 cen­time­ters), sug­gest they were made by a male mem­ber of the species known as Aus­tralo­p­ithe­cus afaren­sis. The prints were found at a site called Lae­toli, which is fa­mous for an­other set of smaller foot­prints left by other A. afaren­sis in­di­vid­u­als. Those made head­lines in the 1970s as the ear­li­est clear ev­i­dence of up­right walk­ing by our an­ces­tors. The newly dis­cov­ered prints are only about 160 yards (150 me­ters) away.

Re­searchers named the new crea­ture S1, for the first dis­cov­ery made at the “S” site. From the foot­prints, they cal­cu­lated that he stood about 5-foot-5 (roughly 165 cen­time­ters) and weighed around 100 pounds (about 45 kilo­grams). They fig­ured that he loomed at least 8 inches (more than 20 cen­time­ters) above the in­di­vid­u­als who made the other tracks, and stood maybe 3 inches (7 cen­time­ters) taller than a large A. afaren­sis spec­i­men pre­vi­ously found in Ethiopia. “Lucy”, also from Ethiopia, was much shorter at about 3 1/2 feet (107 cen­time­ters).

New dis­cov­ery

The find­ings are de­scribed in a re­port re­leased yes­ter­day by the jour­nal eLife. Au­thors in­clude Gior­gio Manzi of Sapienza Univer­sity in Rome, Marco Cherin of the Univer­sity of Peru­gia in Italy, and oth­ers. No­body knows the ages or sexes of any of the track-mak­ers, al­though the size of the lat­est foot­prints sug­gest they were made by a male. It’s quite pos­si­ble that the new dis­cov­ery means A. afaren­sis males were a lot big­ger than fe­males, with more of a dif­fer­ence than what is seen in modern hu­mans, the re­searchers say. That’s not a new idea, but it’s still un­der de­bate.

The large male-fe­male dis­par­ity sug­gests A. afaren­sis may have had a go­rilla-like so­cial ar­range­ment of one dom­i­nant male with a group of fe­males and their off­spring, the re­searchers said. But not ev­ery­body agrees with their anal­y­sis of S1’s height. Their es­ti­mate is sus­pect, says an­thro­pol­o­gist Wil­liam Jungers, a re­search as­so­ci­ate at the As­so­ci­a­tion Va­ha­tra in Mada­gas­car who wrote a com­men­tary on the study. That’s be­cause sci­en­tists haven’t re­cov­ered enough of an A. afaren­sis foot to re­li­ably cal­cu­late height from foot­prints, he said in an email.

Philip Reno, an as­sis­tant an­thro­pol­ogy pro­fes­sor at Penn State who didn’t par­tic­i­pate in the new work, said he be­lieved the height es­ti­mate was in the right ball­park. But he’s not con­vinced that S1 was re­ally taller than the large Ethiopian A. afaren­sis. So rather than set­ting a record, “I think it con­firms about the size we thought the big spec­i­mens were,” Reno said. Manzi and Cherin said they can’t be sure S1 was taller than the Ethiopian spec­i­men. “We only sug­gest,” they wrote in an email. —AP

TAN­ZA­NIA: This un­dated photo pro­vided by Raf­faello Pel­liz­zon in De­cem­ber 2016 shows fos­silized foot­prints of a hu­man an­ces­tor, be­lieved to be Aus­tralo­p­ithe­cus afaren­sis, at the Lae­toli site in north­ern Tan­za­nia. —AP

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