USING MUSEUM COLLECTIONS TO STUDY BRACHIOPOD SIZE CHANGE ACROSS EXTINCTION BOUNDARIES - TAKING ADVANTAGE OF MASS DIGITISATION

Brachiopods are useful for understanding the how biota have responded to environmental changes in deep time as they commonly occur throughout the record from a range of habitats. To better understand how to use existing museum collections as data sources, we completed a collections survey to compile information on the quality of preservation and metadata associated with the post Palaeozoic brachiopod collections at the NHM. These data were used to help define priorities for a large-scale collection digitisation programme. It has become standard practice in many museums to digitize collections, however most new initiatives use high-throughput workflows based on rapidly imaging material to allow metadata to be transcribed at a later stage. We are interested in digitisation workflows applied to collect standardised morphological data to document changes in size across intervals of rapid environmental change. This required that all specimens were oriented in a consistent manner to allow size and other morphological data to be efficiently extracted using computer vision techniques. To test our new digization and data processing workflow, we completed a pilot study of a well documented collection of 1200 brachiopods from the Jurassic of Spain. Analysis of several size estimators in three views indicates significant size reduction across the Pliensbachian / Toarcian boundary that has been documented for other taxa. This approach improves replicability of size measurements as compared to manual measurements of shells using calipers, but it requires good quality images so that shells can be automatically segmented from image backgrounds.