2.1 Presence records
We searched presence records with geographic coordinates for all sea
snakes in public online repositories. These platforms were the Global
Biodiversity Information Facility (gbif.org; DOI information associated
with data are available in Table SM1), VertNet (vertnet.org), the Ocean
Biogeographic Information System (obis.org), the Atlas of Living
Australia (ala.org.au), the Online Zoological Collections of Australian
Museums (ozcam.org.au) and the UNAM open data portal
(datosabiertos.unam.mx). We integrated the presence records obtained
from the different platforms into a single database per species. Then,
we eliminated duplicate records, uncertain data (e.g., taxonomic
mistakes, records outside the known distribution of the group), and
obvious errors (e.g., records in terrestrial environments). Next, we
eliminated occurrences that might represent sink populations through an
environmental outliers’ analysis. In this process, we considered
environmental variables previously identified in the literature as
important to the group (see below). For this, we used theoutliers function of the “biogeo” package (Robertson et al.
2016) in R (R Core Team 2013), which searches for presence records that
are located at a distance above 1.5 times the interquartile range of the
data. Additionally, we employed the gridSample function of the
“dismo” package (Hijmans et al. 2017) to minimize data bias towards
more intensely sampled environments. These processed records comprised
the complete database for each species.