High resolution in turbid waters: Ampullae of lorenzini in the daggernose shark Carcharhinus oxyrhynchus (Valenciennes, 1839) (Elasmobranchii: Carcharhinidae).

Abstract

The present work aimed to analyze the distribution of the electrosensory pores of the Daggernose Shark Carcharhinus oxyrhynchus identifying the organ's importance in the natural history of the species. By examining photographs and digital microscope videos, we found that C. oxyrhynchus possesses the highest abundance of pores among Carcharhiniformes. This suggests a well-developed electroreceptor system, which may have maximized its evolutionary success in high turbidity environments. Furthermore, as a morphologically derived species, C. oxyrhynchus comprises a more complex and specialized electrosensory system. Notably, the species exhibits ontogenetic variation in pore abundance, highlighting the importance of a high-resolution system for adults. The higher density of pores in the ventral region indicates a preference for benthic prey, despite also feeding on pelagic items. Moreover, the species has a high-resolution electrosensory system and a high density of pores in the snout, which emphasizes the importance of the elongated snout that expands the electroreception search area coverage. Evolutionary convergence was observed in the development of the electrosensory system, as C. oxyrhynchus shares characteristics of pore distribution and abundance with phylogenetically unrelated species.