2.5 Asymmetry of the realized thermal niche
We extracted the mean, maximum, and minimum temperature values for the five groups depending on the repository and depth (Bsurf, Bma, Bme, Bmi, and Msurf) associated with each post processed presence record (see above in “2.1 Presence records”) of each species at 5 and 10 arc-minutes of spatial resolution. For Bio-Oracle, we used directly the mean, maximum, and minimum temperature variables in each depth. In the case of MARSPEC, we used the surface temperature of the warmest month to represent the maximum temperature and the surface temperature of the coldest month to represent the minimum temperature. With those values, we conserved and grouped the minimum and maximum value from each species for characterized the lower and upper TNR limits respectively.
Finally, we tested the asymmetry in TNR limits hypothesis (asymmetry in the variances with more variance in lower limit) by testing the homogeneity of variances between the lower and upper realized thermal limits. This process was repeated for each variable group on each temperature measurement at the three taxonomic levels and two spatial resolution by applying a non-parametric Fligner-Killeen test (Fligner and Killeen 1976) (5 groups × 3 temperatures × 3 taxonomic levels × 2 resolutions). Particularly, in genus level, we excluded the genus Laticauda due to represent the same result at the Laticaudinae subfamily, and Ephalophis andMicrocephalophis as a result of only have data for one species.