Distribution and morphology of the ampullae of Lorenzini in coastal and pelagic sharks from the Mexican Pacific

The electrosensory system in elasmobranchs is composed of specialized structures called the ampullae of Lorenzini, located in the anterior region of the head. These organs can detect weak electric fields. The electroreceptors are distributed in the dorsal and ventral cephalic skin and play a central role in prey detection. Their morphology, distribution, and density are primarily determined by phylogeny and are closely related to the species’ ecology. In the present study, we analyzed the abundance, spatial distribution, and histological features of the ampullae of Lorenzini in four shark species from in four shark species off the coast of Baja California Sur, Mexican Pacific. Sphyrna zygaena, exhibited the highest mean pore count (1938 ± 41.5), followed by Mustelus henlei (863 ± 22.15), Prionace glauca (790 ± 16.8), and Isurus oxyrinchus (438 ± 25.1). The ampullae exhibited variable morphology among species, with no evidence of cellular differentiation. Oceanic species (P. glauca and I. oxyrinchus) had fewer pores but larger ampullae compared with coastal species (S. zygaena and M. henlei). This study improves the knowledge of the electrosensory system by revealing variation in the distribution and morphology of these ampullae in sharks with different foraging strategies.