Table 3. Overview of Poecilia mexicana populations investigated, methods used, and number of specimens analyzed.

Population	Habitat type	Brain preparation/μ-CT of heads	Orientation patterns (SEM, CLSM)	3D reconstruction of end organs	Transversal semithin-sections of the saccule
Cueva del Azufre chamber XIII)	cave creek free of hydrogen sulfide; complete darkness	3/1	4	1	2
Río Oxolotán	sulfide-free river in the vicinity of the cave system; surface habitat	1/1	4	-	2
Tampico	brackish coastal waters; surface habitat	2/-	1	1	2

Investigation of the orientation patterns of ciliary bundles of sensory hair cells was performed using either a scanning electron microscope (SEM) or a confocal laser scanning microscope (CLSM).