Was Darwinius a little longer in the tooth than previously thought?

New model proposed for famous primate fossil based on dental eruption sequence

University of Toronto


IMAGE: Darwinius is one of the best preserved early fossil primates known to exist. view more

Credit: Jens L. Franzen et al: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0005723;jsessionid=E8154D7406947B36A39470C790A4F08C

A famous fossil of an early primate shares more in common with modern lemurs based on how its teeth erupted, according to new model developed at U of T Scarborough.

The model, developed by PhD student Sergi López-Torres and Associate Professors Mary Silcox and Michael Schillaci, re-examined the interpretation of Darwinius, the best preserved fossil primate known to exist.

By looking at the sequence in which adult teeth come in – known as dental eruption – in primates, they found it had more in common with lemurs than squirrel monkeys, the model species used by the researchers who discovered Darwinius.

“Every species has a particular pattern by which their teeth come in and this allows us to estimate the age of fossils that died before their adult teeth could emerge,” says López-Torres. “It seems that the pattern of dental eruption for Darwinius is more similar to that of lemurs than to that of monkeys.”

Before looking at Darwinius, López-Torres did a large study of 97 living and fossil primates in order to get a clearer picture of how different species compare through patterns of dental development. He found that the three most primitive ancestors – the ancestor to lemurs and lorises, the ancestor to monkeys, apes, and tarsiers, and the ancestor to all primates – share the same eruption sequence with each other. That pattern shares some similarities with the dental eruption sequence found in Darwinius. Read more.