Data and scripts from: Shark fossil localities, in diving deeper: Leveraging the chondrichthyan fossil record to investigate environmental, ecological, and biological change

The extensive chondrichthyan fossil record spans 400+ million years and has a global distribution. Paleontological studies provide a foundation of description and taxonomy to support deeper forays into ecology and evolution considering geographic, morphologic, and functional changes through time with non-analogue species and climate states. Although chondrichthyan teeth are most studied, analyses of dermal denticle metrics and soft tissue imprints are increasing. Recent methodological advances in morphology and geochemistry are elucidating fine-scale details, whereas large datasets and ecological modeling are broadening taxonomic, temporal, and geographic perspective. The combination of ecological metrics and modeling with environmental reconstruction and climate simulations are opening new horizons to explore form and function, demographic dynamics, and food web structure in ancient marine ecosystems. Ultimately, the traits and taxa that endured or perished during the many catastrophic upheaval events in Earth’s history contribute to conservation paleobiology, which is a much-needed perspective for extant chondrichthyans. 

Methods
The Paleobiology Database download was performed on February 3, 2024 using the following query: http://paleobiodb.org/data1.2/occs/list.csv?datainfo&rowcount&base_name=Chondrichthyes&pgm=gplates,scotese,seton&show=full,classext,genus,subgenus,acconly,ident,img,etbasis,strat,lith,env,timebins,timecompare,resgroup,ref,ent,entname,crmod. 
We refined data to match the cleaning protocols designed by E. Sibert for Whitenack, Lisa B., Sora L. Kim, and Elizabeth C. Sibert. "Bridging the gap between chondrichthyan paleobiology and biology." In Biology of Sharks and Their Relatives, pp. 1-29. CRC Press, 2022 and is in “chond.occurrences.csv”.

We use the following broad taxonomic groupings: Stem Chondrichthyan, Stem Holocephali, Holocephali, Hybodonta, Selachii, and Batomorphii. Groups for each order are found in the file “groups_order.csv”.

We use the following time periods: Paleozoic, Mesozoic, and Cenozoic. We cleaned up the intervals and assign time periods found in the file “time.csv”.

We ignore occurrences for which we cannot assign a group. We also ignore occurrences without obvious site-level metadata. We additionally remove obvious taxonomic and site errors.

Localities can be in multiple time periods if their earliest interval to latest interval spans two time periods. For example, the Takatika Grit Formation in New Zealand spans the Campanian (83.6 Mya, Mesozoic) to the Middle Paleocene (58.7 Mya, Cenozoic).

The script to clean the data and tally localities based on taxonomic group and time period is “shark_localities_AREPS.R”.