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Evo­lu­tion


A Col­lec­tion of News by Moos


201420Mar07:21

Pre­cur­sor of extinct Euro­pean rhi­nos found in Vietnam

Infor­ma­tion
pub­lished 20 March 2014 | mod­i­fied 10 May 2014
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A team of sci­en­tists from the Uni­ver­sity of Tübin­gen and the Senck­en­berg Cen­ter for Human Evo­lu­tion and Palaeoen­vi­ron­ment Tübin­gen (HEP) was able to recover fos­sils of two pre­vi­ously unknown mam­mal species that lived about 37 mil­lion years ago. The newly described mam­mals show a sur­pris­ingly close rela­tion­ship to pre­his­toric species known from fos­sil sites in Europe. The loca­tion: The open lignite-​mining Na Duong in Viet­nam. Here, the team of sci­en­tists was also able to make a series of fur­ther dis­cov­er­ies, includ­ing three species of fos­silized croc­o­diles and sev­eral new turtles.

Extinct rhino Epiceratherium naduongense remainsSouth­east Asia is con­sid­ered a par­tic­u­larly species-​rich region, even in pre­his­toric times – a so-​called hotspot of bio­di­ver­sity. For sev­eral decades now, sci­en­tists have pos­tu­lated close rela­tion­ships that existed in the late Eocene (ca. 3834 mil­lion years ago) between the fau­nas of that region and Europe. The recent find­ings by the research team under lead­er­ship of Prof. Dr. Made­laine Böhme serve as proof that some Euro­pean species orig­i­nated in South­east Asia. The find­ings have been pub­lished on 31 Decem­ber last year in the Jour­nal Zit­teliana, the Bavar­ian State Col­lec­tion for Pale­on­tol­ogy and Geology.

Rhi­noc­eros and Coal beast
One of the newly described mam­mals is a rhi­noc­eros, Epi­ac­eratherium naduon­gense. The anatomy of the fos­sil teeth allows iden­ti­fy­ing this rhi­noc­eros as a poten­tial for­est dweller. The other species is the so-​called “Coal Beast”, Bakalovia ori­en­talis. This pig-​like ungu­late, closely related to hip­pos, led a semi-​aquatic lifestyle, i.e. it pre­ferred the water close to bank areas. At that time, Na Duong was a forested swamp­land sur­round­ing Lake Rhin Chua. The mam­mals’ remains bear signs of croc­o­dile attacks. Indeed, the exca­va­tion site at Na Duong con­tains the fos­silized remains of croc­o­diles up to 6 meters in length.

From island to island toward Europe
In the Late Eocene, the Euro­pean main­land pre­sented a very dif­fer­ent aspect than it does today. Italy and Bul­garia were part of an island chain in the Tethys Sea. These islands spanned sev­eral thou­sand kilo­me­ters between what later became Europe and India. Euro­pean fos­sils from that epoch are very rare, since lit­tle mate­r­ial has been pre­served due to the fold­ing of moun­tains and ero­sion. Yet, the two new species had rel­a­tives in this area: A rhi­noc­eros Epi­ac­eratherium bol­cense closely resem­bling the one from Na Duong was found in Italy (Mon­te­viale). Fos­sil finds of Epi­ac­eratherium mag­num from Bavaria indi­cate that rhi­noc­er­oses reached con­ti­nen­tal Europe no later than 33 mil­lion years ago and col­o­nized the land­mass. The coal beast did not quite make it to the Euro­pean main­land – but it cer­tainly reached the so-​called Balkano-​Rhodopen Island: a fos­silized coal beast very sim­i­lar to Bakalovia ori­en­talis was unearthed in present-​day Bulgaria.

Research among coal dust and exca­va­tors
The open min­ing pit Na Duong is still active. While the sci­en­tists con­duct their exca­va­tions, lig­nite is being extracted nearby. Since 2008, the inter­na­tional research team around Prof. Dr. Made­laine Böhme from HEP at the Uni­ver­sity of Tübin­gen has stud­ied the pre­his­toric ecosys­tem and the fos­sils of Na Duong in Viet­nam. This research revealed that the lig­nite seams con­tained a glob­ally impor­tant fos­sil deposit from the Pale­o­gene inter­val. Orig­i­nally, sci­en­tists had expected to find fos­sils from the younger Ceno­zoic (up to 23 mil­lion years ago) at the site.
This ecosys­tem, which the sci­en­tists from Viet­nam, France and Ger­many explore and recon­struct in ever more detail from one exca­va­tion sea­son to the next, is a 37 mil­lion year-​old swamp for­est in a trop­i­cal to sub­trop­i­cal cli­mate. Up to 600 trees grew there per hectare, and their crowns reached heights of up to 35 meters.



(Source: Senck­en­berg press release, 12.03.2014)


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

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