logo

Welcome


AboutZoos, Since 2008





201309Jun19:49

Researchers dis­cov­ered the oldest-​known fos­sil pri­mate skeleton

Infor­ma­tion
pub­lished 09 June 2013 | mod­i­fied 30 May 2014
Archived

Archicebus-achillesAn inter­na­tional team of researchers has announced the dis­cov­ery of the world’s old­est known fos­sil pri­mate skele­ton rep­re­sent­ing a pre­vi­ously unknown genus and species named Archice­bus achilles. The fos­sil was unearthed from an ancient lake bed in cen­tral China’s Hubei Province, near the course of the mod­ern Yangtze River. In addi­tion to being the old­est known exam­ple of an early pri­mate skele­ton, the new fos­sil is cru­cial for illu­mi­nat­ing a piv­otal event in pri­mate and human evo­lu­tion — the evo­lu­tion­ary diver­gence between the lin­eage lead­ing to mod­ern mon­keys, apes and humans (col­lec­tively known as anthro­poids) on the one hand and that lead­ing to liv­ing tar­siers on the other. The sci­en­tific paper describ­ing the dis­cov­ery was pub­lished online 5 June in Nature.

The inter­na­tional team of sci­en­tists who stud­ied the skele­ton of Archice­bus was led by Dr. Xijun Ni of the Insti­tute of Ver­te­brate Pale­on­tol­ogy and Pale­oan­thro­pol­ogy (IVPP) at the Chi­nese Acad­emy of Sci­ences in Bei­jing. Accord­ing to Dr. Ni, “Archice­bus marks the first time that we have a rea­son­ably com­plete pic­ture of a pri­mate close to the diver­gence between tar­siers and anthro­poids. It rep­re­sents a big step for­ward in our efforts to chart the course of the ear­li­est phases of pri­mate and human evolution.”

Archice­bus achilles
The skele­ton of Archice­bus is about 7 mil­lion years older than the old­est fos­sil pri­mate skele­tons known pre­vi­ously, which include Dar­winius from Mes­sel in Ger­many and Notharc­tus from the Bridger Basin in Wyoming. Fur­ther­more, Archice­bus belongs to an entirely sep­a­rate branch of the pri­mate evo­lu­tion­ary tree that lies much closer to the lin­eage lead­ing to mod­ern mon­keys, apes and humans. Dar­winius and Notharc­tus, on the other hand, are adapi­form pri­mates that are early rel­a­tives of liv­ing lemurs, the most dis­tant branch of the pri­mate fam­ily tree with respect to humans and other anthropoids.

Co-​author Dr. Christo­pher Beard, whose ear­lier work on Eosimias and other fos­sil pri­mates from China and Myan­mar has placed Asia at the cen­ter of early pri­mate evo­lu­tion, said that,

Archice­bus
dif­fers rad­i­cally from any other pri­mate, liv­ing or fos­sil, known to sci­ence. It looks like an odd hybrid with the feet of a small mon­key, the arms, legs and teeth of a very prim­i­tive pri­mate, and a prim­i­tive skull bear­ing sur­pris­ingly small eyes. It will force us to rewrite how the anthro­poid lin­eage evolved.

Sta­tis­ti­cal analy­ses aimed at recon­struct­ing how much an adult Archice­bus would have weighed in life show that it was slightly smaller than the small­est liv­ing pri­mates, which are pygmy mouse lemurs from Mada­gas­car. Archice­bus would have weighed about 2030 grams (~ 1 ounce). Dr. Daniel Gebo, co-​author and an expert on the evo­lu­tion of body anatomy in pri­mates, said that, “The tiny size and very basal evo­lu­tion­ary posi­tion of Archice­bus sup­port the idea that the ear­li­est pri­mates, as well as the com­mon ances­tor of tar­siers and anthro­poids, were minis­cule. This over­turns ear­lier ideas sug­gest­ing that the ear­li­est mem­bers of the anthro­poid lin­eage were quite large, the size of mod­ern monkeys.”

Another mem­ber of the research team, Dr. Mar­ian Dagosto, notes that, “Even though Archice­bus appears to be a very basal mem­ber of the tar­sier lin­eage, it resem­bles early anthro­poids in sev­eral fea­tures, includ­ing its small eyes and monkey-​like feet. It sug­gests that the com­mon ances­tor of tar­siers and anthro­poids was in some ways more sim­i­lar than most sci­en­tists have thought.”

The evo­lu­tion­ary rela­tion­ships among pri­mates and their poten­tial rel­a­tives, and among the major lin­eages within the Pri­mate order have been debated inten­sively for many years. “To test these dif­fer­ent hypothe­ses and deter­mine the phy­lo­ge­netic posi­tion of the new pri­mate, we devel­oped a mas­sive data matrix includ­ing more than 1000 anatom­i­cal char­ac­ters and scored for 157 mam­mals,” said Dr. Jin Meng, co-​author.

The new fos­sil takes its name from the Greek arche (mean­ing begin­ning or first; the same root as archae­ol­ogy) and the Greek kebos (mean­ing long-​tailed mon­key). The species name achilles (derived from the mytho­log­i­cal Greek war­rior Achilles) high­lights the new fossil’s unusual ankle anatomy.

Archice­bus: exhumed and dig­i­tally res­ur­rected
The fos­sil was recov­ered from sed­i­men­tary rock strata that were deposited in an ancient lake roughly 55 mil­lion years ago, dur­ing the early part of the Eocene epoch. This was an inter­val of global “green­house” con­di­tions, when much of the world was shrouded in trop­i­cal rain­forests and palm trees grew as far north as Alaska. Like most other fos­sils recov­ered from ancient lake strata, the skele­ton of Archice­bus was found by split­ting apart the thin lay­ers of rock con­tain­ing the fos­sil. As a result, the skele­ton of Archice­bus is now pre­served in two com­ple­men­tary pieces called a “part” and a “coun­ter­part,” each of which con­tain ele­ments of the actual skele­ton as well as impres­sions of bones from the other side.

In order to study the entire fos­sil, the sci­en­tific team first had to scan the spec­i­men at ultra high res­o­lu­tion using the state-​of-​the-​art facil­i­ties of the Euro­pean Syn­chro­tron Radi­a­tion Facil­ity in Greno­ble, France. Three-​dimensional dig­i­tal recon­struc­tion of the fos­sil using the syn­chro­tron scans allowed the team of sci­en­tists to study the tiny, frag­ile skele­ton of Archice­bus in intri­cate detail. “Dur­ing the past few years, we at the ESRF have devel­oped the tech­nol­ogy to look at those parts of the fos­sil that are still buried in the rock at a level of detail that is unique in the world. Speak­ing vir­tu­ally, we made the skele­ton stand up,” said Dr. Paul Tafforeau from the research team who is a lead­ing expert in devel­op­ing pale­on­to­log­i­cal appli­ca­tions of highly sophis­ti­cated Syn­chro­tron CT scanning.

Peo­ple may see this sim­ply as another dis­cov­ery of a well pre­served fos­sil, but to reveal the remark­able secrets that have been hid­den in the rock for mil­lions of years, we under­took exten­sive work, applied state-​of-​the-​art tech­nol­ogy, and inten­sive inter­na­tional coop­er­a­tion took place behind the scenes at sev­eral muse­ums. It took us ten years”, added co-​author Dr. John Flynn, dean of the Richard Gilder Grad­u­ate School and cura­tor of the Amer­i­can Museum of Nat­ural History.

(Source: Carnegie Museum of Nat­ural His­tory press release, 05.06.2013)

UN Biodiversity decade
WWF Stop Wildlife Crime
Fight for Flight campaign
End Ivory-funded Terrorism
Support Rewilding Europe
NASA State of Flux

Goal: 7000 tigers in the wild

Tiger range countries map

Tiger map” (CC BY 2.5) by Sander­son et al., 2006.

about zoos and their mis­sion regard­ing breed­ing endan­gered species, nature con­ser­va­tion, bio­di­ver­sity and edu­ca­tion, which of course relates to the evo­lu­tion of species.
Fol­low me on: