The Mexican cave tarantulas: a genus that followed darkness underground, with several species showing reduced eyes and some populations effectively blind, which makes it one of the few tarantula lineages evolving away from light in real time.
They are New World animals with urticating hairs, keeping to cave-adjacent conditions: cool, humid, dark, sheltered, with substrate depth and minimal disturbance. The husbandry is a cellar in a container, and the temperature point matters as much as it does for the highland genera.
Mexican export closure plus cave endemism produces the narrowest founder structure imaginable, and the trade record is nearly empty: rare singles on provenance, priced in a vacuum. The genus trades on evolutionary spectacle to the hobby's deepest collectors, and a blind tarantula is exactly what that shelf exists for.