enzh-TWfrderues

Evo­lu­tion


A Col­lec­tion of News by Moos


201412Jan10:49

New fos­sils shed light on the ori­gins of lions, tigers, and bears

Infor­ma­tion
pub­lished 12 Jan­u­ary 2014 | mod­i­fied 25 Decem­ber 2014
Archived

New fos­sils from Bel­gium have shed light on the ori­gin of some of the most well-​known, and well-​loved, mod­ern mam­mals. Cats and dogs, as well as other car­niv­o­rous mam­mals (like bears, seals, and weasels), tax­o­nom­i­cally called car­nivo­raforms, trace their ances­try to prim­i­tive car­niv­o­rous mam­mals dat­ing back to 55 mil­lion years ago (the begin­ning of the time period called the Eocene). A study, pub­lished online on 7 Jan­u­ary in the Jour­nal of Ver­te­brate Pale­on­tol­ogy, dis­cusses the ori­gins of this group and describes new spec­i­mens of one of the ear­li­est of these prim­i­tive taxa.

Dormaalocyon latouriDormaalocyon phyl tree

Its [the novel iden­ti­fied species] descrip­tion allows bet­ter under­stand­ing of the orig­i­na­tion, vari­abil­ity and ecol­ogy of the ear­li­est carnivoraforms
Floréal Solé, Depart­ment of Pale­on­tol­ogy , Royal Bel­gian Insti­tute of Nat­ural Sci­ences, Brussels »

The species, dubbed Dor­maalo­cyon latouri, had pre­vi­ously been found at the Bel­gian local­ity of Dor­maal (thus the name of the genus). New spec­i­mens found by lead author Floréal Solé and his col­leagues, allow for a bet­ter char­ac­ter­i­sa­tion of the ani­mal, and its place­ment in the evo­lu­tion­ary his­tory of carnivores.

Dormaalocyon teethThe new spec­i­mens include over 250 teeth and ankle bones. More teeth allow for a descrip­tion of the entire tooth row of Dor­maalo­cyon, while pre­vi­ous finds only included two upper molars. The new finds even include the decid­u­ous teeth (or ‘baby teeth’). The fact that these teeth are very prim­i­tive look­ing, and from a very early time, implies that Dor­maalo­cyon is close to the ori­gin of car­nivo­raforms, and that this ori­gin may have been in Europe.

Dor­maalo­cyon may have looked a bit like a cross between a squir­rel and a small puma. Its oral fea­tures show impor­tant adap­ta­tions to a meaty diet. The small car­niv­o­rous mam­mal – 0.5 to 1 kilo­gram in size – likely con­sumed insects and other ani­mals smaller than itself [National Geographic].

The ankle bones sug­gest that Dor­maalo­cyon was arbo­real, liv­ing and mov­ing through the trees. Pre­vi­ous recon­struc­tions of the envi­ron­ment at Dor­maal 55 mil­lion years ago inferred a warm, humid, and wooded area. This was a time soon after an event called the Paleocene-​Eocene Ther­mal Max­i­mum (or PETM). This extremely warm period affected the evo­lu­tion of many mam­mal groups, includ­ing car­nivo­raforms. Dr. Solé believes that there existed a con­tin­u­ous ever­green for­est belt at high lat­i­tudes dur­ing the PETM, due to the fact that Dor­maalo­cyon was arbo­real, and that car­nivo­raforms made their way to North Amer­ica around this time,.

Although close to the ori­gin of car­nivo­raforms, the fos­sils sug­gest there were even more prim­i­tive species in the group in an ear­lier time period, the Pale­ocene. Says Solé, “The under­stand­ing of the orig­i­na­tion of the car­nivo­raforms is impor­tant for recon­struct­ing the adap­ta­tion of pla­cen­tal mam­mals to car­niv­o­rous diet. There­fore, Dor­maalo­cyon pro­vides infor­ma­tion con­cern­ing the evo­lu­tion of pla­cen­tal mam­mals after the dis­ap­pear­ance of the largest dinosaurs (at the Cre­ta­ceous – Pale­o­gene extinc­tion event). Our study shows that the car­nivo­raforms were very diver­si­fied at the ear­li­est Eocene, which allows hypoth­e­siz­ing that they were prob­a­bly already diver­si­fied dur­ing the lat­est Pale­ocene”. This means there are more fos­sils out there to be found that can answer the ques­tion of the ori­gin of this beloved mod­ern group.



(Source: Soci­ety of Ver­te­brate Pale­on­tol­ogy press release, Jan­u­ary 2014; National Geo­graphic news, 09.01.2014)


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: