Overview of samples used in this study for morphometric and population genetic analyses.

<p>The table highlights the collection sites of <i>P. mexicana</i>, <i>P. thermalis</i>, and <i>P. sulphuraria</i> samples used for the morphological analyses and populations genetics. Also indicated are presence (+) and absence (−) of hydrogen sulfide (H₂S), GPS coordinates, species, and the total number of specimens examined, split by sex (only for morphology).