Traces of the structural protein collagen have recently been reported
in Cretaceous dinosaur fossils, based primarily on mass
spectrometric analyses of bone extracts [11]. Exceptionally, some
well-preserved embryos from Cretaceous or Jurassic periods could
be found in eggshell form when avian dinosaur nests were buried
and maintained in anaerobic condition thereafter [12–14]. However,
there is a growing body of evidence that most of dinosaur specimens
can contain only exogenous amino acids, although traces of
endogenous amino acids may be present in some cases [13]. It is
commonly considered that plant and animal biomacromolecules
provide a structural template that is subsequently diagenetically
altered to geomacromolecules in fossils [15], thus leading to new
chemical species. A conservative view of diagenesis processes is
simply to consider that time is making that most, if not all, molecular
contents are mineralized in a time course that does not exceed
a few million years. A few carbon-rich molecular compounds may
be observed, but nothing related to the native molecular structures
could be considered thereof. However, a growing body of
evidence appeared in the last decade that organic remains from
various molecular origins (lipids, proteins, sugars, maybe nucleic
acids) could have been exceptionally preserved. Thus, the fine structure
analysis of these molecular fragments could renew our
knowledge on ancient molecular species.