Darwinius massilae
Without question, human ancestry has been and will remain the focus of public attention paid to evolutionary biology. And for at least the last 100 years, one of the popular concerns has been finding “the missing link”, that fossil or set of fossils that connect modern humans with more apelike ancestors. One such case, that of Piltdown Man, was shown to be a fraud nearly sixty years ago, however new possibilities continue to arise .

One of the most recent was “Ida” (Darwinius masillae), a 47 million year old fossil found in Germany, preserved in a private collection for many years, and then carefully analyzed and proposed as possibly one of the earliest known ancestors of modern man by Jorn Hurum and his colleagues in the Public Library of Science (PLOS).

Normally, the publication of a peer-reviewed publication does not generate a lot of publicity, however in this case, all bets were off.  The journal that published the paper, PLOS One, went to some effort to stage manage the release, as they described in a cover piece included with the electronic edition containing the paper.

As the editors anticipated (and the authors seem to have planned – see the conflict of interest disclosure that was added subsequent to publication), the paper garnered considerable attention, with news stories in outlets ranging from The Guardian to The New York Daily News.  It became the subject of a commercial documentary, a portion of which can be seen below.  In all cases, the initial reaction seemed to be that indeed “The Missing Link” had been found.

 

Not so fast, however. Even during the peer review process, questions were raised as to whether “Ida” was truly a lineal ancestor of the higher primates like man, or whether in fact it was near the base of the lineage giving rise to the likes of lemurs and lorises (also primates, but very distantly related to us). The paper was published on May 19; by July 21st, Scientific American reported growing skepticism among paleontologists. In October, 2009, Eric Seiffert and his colleagues reported the discovery of a 37 million-year-old fossil species in Egypt, dubbed Afradapis longicristatus, analysis of which placed it and Ida in a lineage far distant from the one leading to modern humans (see summary from Nature and the figure below taken from it).

Ida tree
This post is by no means meant provide a completely up-to-date story; no doubt much more has transpired in the ensuing two years. However, it provides an excellent case in which we can consider two related questions:

  • Although the initial research paper received full peer review, subsequent scientific work called a key conclusion of it into question. To what extent does this affect the value or significance of the initial finding?
  • What should the proper relationship be between scientists, the editors and publishers of peer-reviewed papers, and the popular press?
Here is an additional perspective on the controversy from Discovery, which addresses both of these questions.