A huge new di­nosaur

The Week (US) - - 20 News -

Pa­le­on­tol­o­gists in South Africa have dis­cov­ered the fos­silized re­mains of a gi­gan­tic new species of di­nosaur re­lated to the bron­tosaurus. Le­duma­hadi ma­fube was an early type of sauropodomorph, a group of long­necked, long-tailed di­nosaurs that lived about 200 mil­lion years ago in the early Juras­sic pe­riod. Weigh­ing 26,000 pounds— about as much as two adult African ele­phants—and stand­ing 13 feet high at the hips, it was the largest land an­i­mal on the planet at the time. Re­searchers be­lieve that Le­duma­hadi ma­fube, whose name means “a gi­ant thun­der­clap at dawn” in the Sesotho lan­guage, walked on all fours in a cat-like crouch. That pos­ture was very dif­fer­ent from its later, straight-limbed rel­a­tives’, mean­ing the di­nosaur was ef­fec­tively an evo­lu­tion­ary ex­per­i­ment. Some of its fos­silized bones were found in 1990, but the pa­le­on­tol­o­gist who ex­ca­vated them was in­ter­ested in mam­mals, not di­nosaurs, so they went un­stud­ied for years. “It’s amaz­ing,” study co-au­thor Jonah Choiniere, from the Univer­sity of the Witswa­ter­srand in Jo­han­nes­burg, tells Na­tion­alGeo­graphic .com. “Some­times stuff can sit on your shelf, and you pass by it ev­ery day, but you don’t look at it in de­tail.”

Gu­atemala, us­ing a ground­break­ing new laser-map­ping tech­nol­ogy. The re­searchers flew over 830 square miles of dense for­est in a plane equipped with a li­dar de­vice, which rained mil­lions of light pulses on the canopy to re­veal the con­tours of the ground be­neath. The sur­vey re­vealed an as­ton­ish­ing 61,480 Mayan struc­tures, many of them never seen be­fore. There were large houses and tem­ples; 60 miles of cause­ways, roads, and canals; even de­fen­sive for­ti­fi­ca­tions, such as moats, which sug­gest the Maya came un­der at­tack from other Cen­tral Amer­i­can peo­ples. The dis­cov­er­ies pro­vide a unique snap­shot of the Maya, who lived in the re­gion from about 1000 B.C. to 1500 A.D., and should help sci­en­tists un­der­stand more about their pop­u­la­tion size, agri­cul­tural tech­niques, and con­flicts. Af­ter an­a­lyz­ing the scans, the re­searchers ex­plored the jun­gle at ground level to ver­ify some of their find­ings. “We were all hum­bled,” lead au­thor Mar­cello Canuto, from Tulane Univer­sity in New Or­leans, tells The Washington Post. “All of us saw things we had walked over, and we re­al­ized, ‘Oh wow, we to­tally missed that.’”

qual­i­ties that made them use­ful—sta­bil­ity and heat re­sis­tance—also make them hard to break down. They be­come more con­cen­trated at each stage of the food chain, and at the top of the chain, con­sum­ing PCBs in the high­est con­cen­tra­tions, are killer whales. Or­cas are par­tic­u­larly vul­ner­a­ble to the chem­i­cals, which af­fect their im­mune sys­tem and ham­per their abil­ity to re­pro­duce. Af­ter study­ing PCB lev­els in 351 killer whales, re­searchers con­cluded that pop­u­la­tions of the mam­mal in the wa­ters off Ja­pan, Brazil, Hawaii, Gi­bral­tar, and the U.K. “are all tend­ing to­ward com­plete col­lapse.” Paul Jep­son, from the Zoo­log­i­cal So­ci­ety of Lon­don, de­scribes the de­cline as “like a killer whale apoc­a­lypse.”

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