“Ida” is a beautiful fossil. A few weeks ago, she became a very famous one,
when the squashed-flat remains of this squirrel-sized creature that lived
some 47 million years ago, in quasi-tropical forest around a crater lake in
what is now Germany, were pictured on every medium known to mankind.
Overcome by exhalations of volcanic gas from the lake’s depths, and
apparently already weakened by injury, Ida had fallen in and found herself
preserved, along with the bodies of a remarkable variety of other animals,
in the accumulating muds of the lake floor.
Like us, Ida was a member of the zoological group known as the Primates.
Today, there are two major kinds of primate in the world: the very
successful “higher” ones, consisting of monkeys and apes along with
ourselves; and the now largely marginalized “lower” primates that include
the lemurs of Madagascar and the lorises, pottos and bushbabies of the
tropical Old World. The lower primates share grasping hands with the higher
ones, but they are smaller-brained, and depend more on the sense of smell.
What is more, all of those living today have two very peculiar anatomical
features that show they belong to a single compact evolutionary group. These
are elongated front teeth in the lower jaw that point straight forward,
forming a “tooth comb” that is used among other things for grooming the fur;
and a “toilet claw” instead of a flat nail on the second digit of the foot.
Back in Ida’s day (the Eocene epoch, 56–34 million years ago), things were
rather different. Although this was the age of the earliest “primates of
modern aspect”, there were no monkeys or apes; indeed there were no
candidates at all for higher primate status until quite close to the end of
the epoch. Putative early higher primate fossils from the Eocene of eastern
Asia and northern Africa are few, mostly fragmentary and hotly debated.
Almost all known Eocene primates belonged to one of two large and now
entirely extinct groups. One, the adapiforms, broadly compares with the
lemurs, although few believe there is any direct evolutionary connection
between the two. The other group comprises the smaller-bodied omomyiforms,
which invite comparison with today’s enigmatic tarsier.
Among all those Eocene primates, Ida is clearly an adapiform, and an
unremarkable one at that. What makes her amazing is not what she is but her
completeness – even if she has several rivals for the role of “most complete
fossil primate” that is repeatedly claimed for her in Colin Tudge’s new book
The Link: Uncovering our earliest ancestor. Lying tranquilly at the bottom
of that oxygen-poor lake, almost all of Ida’s bones were preserved in the
fine-grained sediments, as well as the general outline of her body and some
hints of fur and even her stomach contents. Such preservation is rare
indeed; and even at the Messel pit, the hugely prolific fossil-bearing site
near Darmstadt from which Ida was recovered, only a handful of other, less
complete primates is known, all of them adapiforms closely related to her.
On the minus side, like all Messel fossils Ida is pretty badly flattened, so
that while such features as her limb proportions are well conserved, much of
her bony detail is not.
Still, as a snapshot of an adapiform frozen in time, Ida is indeed
extraordinary. She was a young female who died before attaining maturity.
Her shortish limbs are proportioned like those of an unspecialized leaper,
and her grasping extremities amply confirm that she lived in the trees. Her
stomach contents bear out inferences from her teeth that her diet included
fruit and leaves. Judging from reconstructions of her crushed orbits she had
fairly big eyes, suggesting that she was active largely at night. Lacking
both those forward-pointing lower front teeth and a toilet claw, Ida was
clearly not a lemur; but although a member of a long-extinct group, she did
resemble some of the more generalized Madagascar primates more closely than
anything else living today. Like lemurs, she would have been social –
although that probably didn’t mean living in large groups – and she would
have explored her environment with her nose as well as with her eyes. And
that’s about as much as the average person would want to know about Ida.
Apart, that is, from the cloak-and-dagger history of how she was found –
which appears to supply the real reason for her meteoric rise to stardom.
According to Tudge, Ida was discovered in the early 1980s, when the Messel pit
was under threat of becoming a landfill site. Clandestinely collected, she
was hidden away by her keeper until 2006, when a dealer offered her to Jørn
Hurum, a previously obscure curator of fossils at the Oslo Natural History
Museum. Recognizing that Ida was an important specimen, Hurum persuaded the
Museum’s board of directors to pay something in the region of $1 million for
her (this was the asking price, and although Tudge refers to “negotiations”,
he says nothing to indicate it was ever reduced). Most palaeontologists were
aghast to learn this: when fossils become hugely valuable collectibles, more
of them inevitably become lost to science, permits to collect them
scientifically become more difficult to obtain, and illegal plundering of
fossil sites soars.
Clearly, the almost unimaginable sum paid for Ida had to be justified in some
way, and it was certainly reasonable for Hurum to assemble a “Dream Team” of
German and American scientists to study the specimen. Sworn to secrecy, the
Team duly came up with a paper reporting that the fossil shared a half-dozen
characters with higher primates. Actually, the best of these show no more
than that she wasn’t a lemur, and the few remaining are very arguable
(Shortish face? Well, that’s typical of all young female primates. Sloping
fibular facet on the ankle bone? Some other mammals have that, and anyway
the bone appears to be too badly crushed to say much about the facet). Such
dubious minutiae notwithstanding, Ida emerged from the analysis as
overwhelmingly adapiform, and the Team unhesitatingly classified her in that
lower primate group.
All of which was interesting, but left the problem that a million dollars had
been spent on a mere adapiform. Suddenly, in mid-May this year, the news
embargo lifted and Ida was at the centre of a television-orchestrated media
blitz such as has never before greeted any fossil. Endorsed by
uncharacteristically credulous natural history museums on both sides of the
Atlantic, Ida was introduced to the world in a blizzard of publicity
materials and television specials that presented her as the ultimate “link”
between the lower and the higher primates, and the key to our own origins.
“Lying at the very root of anthropoid evolution”, the press release
enthused, Ida “is set to revolutionize our understanding of human
evolution”. It didn’t seem to matter much that this claim was based on
evidence that it would be charitable to describe as tenuous. The telegenic
Hurum proved to be a hypemeister extraordinaire, issuing a series of
declarations among which “this is the Holy Grail of human evolution” was one
of the more restrained.
However, a look at the facts makes it very clear that Ida is a transitional
fossil only in the very limited sense that most people, too, are
transitional, between their parents and their children. Still, the notion of
transition is comfortingly fuzzy. Much worse is the cynical link to humans
that was conjured by comparing Ida to “Lucy”, the three-million-year-old
partial skeleton of a young female that, to most of us, epitomizes the early
“bipedal apes” which were broadly ancestral to modern human beings. This
comparison is spectacularly irrelevant to the materials at hand, and the PR
folk established the connection in terms not of evolutionary significance,
but of the skeletons’ completeness. Both fossils are much more complete than
primate palaeontologists are used to finding; thus both have, by
implication, the same enormous importance for human origins. Even the
fossil’s nickname Ida (used in place of her formal identifier, PMO 214.214),
was conferred in conscious imitation of Lucy (or NME AL 288–1).
Colin Tudge’s book is part of the media blitz; and, at the risk of damning it
with faint praise, I have to say that it is much the best part. It is more
restrained and judicious than the other coverage; and while it does strictly
hew to the party line, the hyperbolic statements it makes are always
carefully attributed to others. To that extent, it is a thoroughly
professional job, as one would expect of a distinguished interpreter of
science to the public.
Understandably, Ida herself doesn’t take up too much of the volume. Instead,
most of what we find in its pages is an amiable, meandering and hugely
repetitive stroll through the environments and faunas of the past 50 million
years. Interspersed with passing references to Ida and some miscellaneous
philosophizing, The Link ends with a quick update on primate and human
evolution. The best part of the book is its evocation of the remarkable
Messel site itself. This extraordinary locality provides an incomparable
window into the world of the Eocene, and the book is well worth reading for
this section alone.
If The Link deserves a prize of any kind, it is for the speed with which it
was written. Your reviewer has it on good authority that the television
producers were still trawling around the Book of Ida project as late as
January of this year; and Tudge evidently found he could not meet the almost
impossibly short time constraints imposed by the TV schedule without
co-opting the assistance of his colleague Josh Young. In combination with
deadline pressure, this co-authorship presumably helps to explain a pattern
of minor and generally harmless inconsistencies and inaccuracies throughout
the book that might have been resolved with more time for reflection. It was
hard, for example, to credit that the same author could have written on page
13 that “dinosaurs and mammals had coexisted briefly”, and (correctly),
later on, that “the oldest known mammals could be older than the first
dinosaurs”. And, in a note at the end of the book, we learn that he didn’t.
In this rather unseemly rush to publication, Tudge and Young were not alone.
Speed, as well as obsessive secrecy, seems to have infected the entire Ida
project from its inception. As reported by Nature, a member of the Dream
Team complained that “there was a TV company involved and time pressure.
We’ve been pushed to finish the study; it’s not how I like to do science”.
I’m sure it’s not how Colin Tudge likes to write books, either.
Colin Tudge with Josh Young
THE LINK
Uncovering our earliest ancestor
262pp. Little, Brown. £18.99.
978 1 4087 0214 7
Ian Tattersall is a curator at the American Museum of Natural History
in New York City. His most recent books are Human Origins: What bones and
genomes tell us about ourselves and World History: Beginnings to 4000 BCE,
both published last year, and The Fossil Trail: How we know what we think we
know about human evolution, 2nd edition, published this year.
