Data from: Variable preservation potential and richness in the fossil record of vertebrates

Variation in preservation and sampling probability clouds our estimates of
past biodiversity. The most extreme examples are Lagerstätten faunas and
floras, or Biotas as they are referred to in China. Although such deposits
provide a wealth of information for palaeontologists and are closer to
representing true richness than other deposits of a similar scale, they
add a disproportionate number of taxa to wider richness counts because of
their exceptional preservation, creating diversity peaks that might be
mistaken for diversification events. Here, we investigate how formations
that have previously been described as, or as hosting, Lagerstätten add to
time series of vertebrate richness in the UK, Germany and China, the
former two representing well-studied fossil records and the latter
representing a region where collecting has a much shorter history. In
fact, Lagerstätten do not drive all dramatic peaks in richness curves and
the proportion of taxa that are unique to Lagerstätten varies through time
and between countries. Lagerstätten uniquely contain a larger proportion
of China’s sampled richness than in Germany and the UK, despite comprising
a smaller proportion of fossiliferous deposits in China. Additionally,
there is little overlap between the taxa occurring in Lagerstätten and
“ordinary” formations within the same time bin, indicating that
Lagerstätten preserve unusual faunas and, as expected, fragile taxa make
up a greater proportion of richness in Lagerstätten than the remainder of
the fossil record. Vastly different sampling probabilities through taxa,
locations and time require serious consideration when quantitatively
analysing richness.