Museum ‘dark data’ show variable impacts on deep-time biogeographic and evolutionary history

The age of digitally accessible datasets has transformed palaeontology,
enabling previously impossible macroevolutionary insights. However, a
substantial reservoir of generally inaccessible ‘dark data’ resides within
museum collections, which may alter our understanding of ancient groups
and their ecological and evolutionary history. We demonstrate how the
addition of data held exclusively in museums impacts our macroevolutionary
understanding of an entire taxonomic group, using a dataset of Palaeozoic
echinoids containing the majority of museum occurrences for the clade. We
find that museum ‘dark data’ shows clear differences in composition
compared to data available in the published literature and strongly
impacts biogeographic patterns, increasing the geographic range size of
taxa by 35% on average. Global model results assessing drivers of
diversity are also significantly affected by the addition of museum only
data. Conversely, “dark data” has a more limited impact on the temporal
ranges of taxa or estimates of overall diversity, and are impacted by
similar socio-geographic biases as the published record. These findings
show that unpublished museum data are necessary to obtaining a complete
understanding of macroevolutionary patterns in deep-time, illustrating the
importance of the collection, curation, digitisation, and continued care
of ‘dark data’ in the age of ‘Big Data’ in palaeobiology.