Body regeneration in the benthopelagic species Physiculus cyanostrophus Anderson & Tweddle, 2002 (Pisces: Gadiformes: Moridae) inhabiting the twilight zone

Abstract

Benthopelagic species inhabiting the twilight zone (200–1000 m) present multiple strategies that are strongly affected by prey-predator densities and lack of light. The morid genus Physiculus currently comprises 42 valid species, showing the highest degree of diversity within the family. Physiculus species are distributed in all tropical, subtropical, and warm-temperate seas of the world ocean at depths of 100– 600 m. They have a ventral light organ which is an important diagnostic feature, with taxonomical importance. The presence of bioluminescence explains several otherwise paradoxical characteristics of body coloration at these depths. The live colouration of P. cyanostrophus -red fins and bluish abdomen wrapping the light organ- is not an exception. Because of predator-prey relationship, several individuals of this species with regenerated caudal region were found. This work aims to give a description of the regeneration pattern of the caudal region and the prevalence of these individuals in a pristine population.