Darwinius masillae

Posted by Chris Clarke on May 19, 2009

Darwinius masillae, an Eocene primate fossil. Photo courtesy PLoS One

[UPDATE: Carl Zimmer deflates some of the hype as well.]

Crazy busy today — first actual paid work in months — but I couldn’t let this announcement go uncommented. What a gorgeous fossil.

Darwinius masillae, this individual of which has been nicknamed “Ida,” lived 47 million years ago during the Eocene. This individual seems to have been killed by something along the lines of a hydrogen sulfide lake eruption, then embedded in lakebed sediments.

There’s a lot of hype surrounding Ida. The execrable phrase “missing link” has been tossed around with abandon. The phrase is a field mark of ignorant science reporting since, as PZ points out,

The whole “missing link” category is a bit of journalistic trumpery: almost every fossil could be called a link, and it feeds the simplistic notion that there could be a single definitive bridge between ancient and modern species. There isn’t: there is the slow shift of whole populations which can branch and diverge.

PZ makes a fantastic point in the three sentences that follow the note above:

It’s also inappropriate to tag this discovery to human evolution. She’s 47 million years old; she’s also a missing link in chimp evolution, or rhesus monkey evolution. She’s got wider significance than just her relationship to our narrow line.

Ida is being trumpeted as ancestral to monkeys, apes and humans, or, more accurately, monkeys and apes (human and otherwise.) This is almost certainly incorrect in a trivial sense: the possibility that Ida’s species, let alone Ida as an individual, is ancestral to any organism living today is, as a friend of mine once put it, astronomically small. But the maternity claims may be incorrect in a non-trivial sense as well. Over at Laelaps, Brian Switek has serious doubts about the quality of the scholarship performed by the authors of the ballyhooed paper describing Ida. The idea that adapids (the primate group to which Darwinius would seem to belong) are more closely related to monkeys and apes than they are to lemurs and lorises is far from being a consensus view. As Brian puts it,

The bottom line is that the hypothesis that Darwinius is closer to anthropoids than tarsiers or omomyids does not have strong support. Even though the authors of the paper constructed a very simple cladogram they did not undertake a full, rigorous cladistic analysis to support their claims. I am baffled as to how they could stress the significance of this fossil without undertaking the requisite research to support their hypothesis.

With a summary like that, I’ll forgive Brian this:

The authors of the paper try to frame their hypothesis in a historical manner. They claim that adapids have been barred from a close anthropoid relationship on the basis of soft-tissue characteristics that do not fossilize. This would mean that the association between omomyids, tarsiers, and anthropoids would hang by a nose…

Ow.

One thing I haven’t seen analyzed much in the press is the role private collection of fossils apparently played in delaying this discussion. A private collector found Ida in 1983 near Darmstadt, Germany, and sold her to two separate buyers. The exact bed horizon from which Ida was collected was not recorded, and one of the halves endured an inauthentic “reconstruction” with other mammal fossils attached to make it look more “real.” As an amateur private fossil collector myself, and someone who has done business with a commercial private collector or two, I wince when I hear stories like this. It’s one thing to pull a herring fossil out of an Eocene lakebed: Knightia are a dime a dozen. But rare fossils are the common property of us all, and private trading in them should be treated as a theft of humanity’s common intellectual property.

In any event, paleontologists eventually figured out what they had on their hands. Whatever lineages Darwinia is eventually determined best to belong within, Ida’s a damn fine fossil. If the authors have oversold her significance for a shot at the Discovery Channel, that’s a shame. But still: wow.