Cut­ting edge

Down to Earth - - COVER STORY -

How cut marks on fos­sil bones were ver­i­fied RE­SEARCHERS USED cut­ting-edge tech­nol­ogy in Paris to ob­serve the marks on three fos­sil bones on a mi­cron scale and to com­pare them with other marks. The fos­sils in­cluded a long bone, a foot bone and a splin­ter of three an­i­mals of the bovid fam­ily that in­cludes buf­falo and bi­son. The fos­sil marks on the foot bone were ob­served us­ing X-ray mi­cro­to­mog­ra­phy at the AST-RX plat­form of the Na­tional Mu­seum of Nat­u­ral His­tory. It is a high­per­for­mance scan­ner that al­lows a 3D high-res­o­lu­tion view from the sur­face to the in­ter­nal struc­ture of the fos­sils. A binoc­u­lar mi­cro­scope was used to look at the sur­face fea­tures of the splin­ter. Then 3D dig­i­tal Video Mi­cro­scope Hirox helped cap­ture 3D images of the sur­face of the long bone, bring­ing into fo­cus the whole section of grooves and scratch marks. These tech­nolo­gies al­lowed an ex­am­i­na­tion of the min­er­al­i­sa­tion of the marks. Min­er­al­i­sa­tion was found to be sim­i­lar to that of bone tis­sue, dis­tin­guish­ing the marks from a fresh trace made by shep­herds.

The cut marks on fos­sils were first com­pared with an­i­mal marks on other fos­sil bones from Ma­sol (car­ni­vores, ro­dents) and a col­lec­tion in Paris (bear, lion, wolf, hyena, Pan­thera, wild cat). The re­searchers then cre­ated cut marks on bones of ex­tant species with quartzite stone col­lected at Ma­sol for com­par­i­son. First they ob­tained flakes of quartzite by strik­ing a stone with a quartzite cob­ble) on large quartzite cob­ble). Us­ing this flake, they cut the sur­face of long bones of a deer skele­ton col­lected at Ma­sol in the area where the ten­dons are at­tached.

Next, they pro­cured a pig foot in

Ho­minin in sa­van­nah

France. A quartzite cob­ble from Ma­sol was bro­ken and its sharp edge used to cut the skin un­til reach­ing the hard sur­face of the bone. The to­pog­ra­phy of the cut marks on ex­per­i­men­tal bones was com­pared to the fos­sil marks of the long bone. They showed the same shape, pro­file and very fine de­tails.

Com­par­i­son of fos­sil (left) and ex­per­i­men­tal cut marks

Newspapers in English

Newspapers from India

© PressReader. All rights reserved.