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Pterosaurs, a Mesozoic group of flying archosaurs, have become a focal
point for debates pertaining to the impact of sampling biases on our
reading of the fossil record, as well as the utility of sampling proxies
in palaeo-diversity reconstructions. The completeness of the pterosaur
fossil specimens themselves potentially provides additional information
that is not captured in existing sampling proxies, and might shed new
light on the group's evolutionary history. Here we assess the quality
of the pterosaur fossil record via a character completeness metric based
on the number of phylogenetic characters that can be scored for all known
skeletons of 172 valid species, with averaged completeness values
calculated for each geological stage. The fossil record of pterosaurs is
observed to be strongly influenced by the occurrence and distribution of
Lagerstätten. Peaks in completeness correlate with Lagerstätten deposits,
and a recovered correlation between completeness and observed diversity is
rendered non-significant when Lagerstätten species are excluded. Intervals
previously regarded as potential extinction events are shown to lack
Lagerstätten and exhibit low completeness values: as such, the apparent
low diversity in these intervals might be at least partly the result of
poor fossil record quality. A positive correlation between temporal
patterns in completeness of Cretaceous pterosaurs and birds further
demonstrates the prominent role that Lagerstätten deposits have on the
preservation of smaller bodied organisms, contrasting with a lack of
correlation with the completeness of large-bodied sauropodomorphs.
However, we unexpectedly find a strong correlation between sauropodomorph
and pterosaur completeness within the Triassic–Jurassic, but not the
Cretaceous, potentially relating to a shared shift in environmental
preference and thus preservation style through time. This study highlights
the importance of understanding the relationship between various
taphonomic controls when correcting for sampling bias, and provides
additional evidence for the prominent role of sampling on observed
patterns in pterosaur macroevolution.
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