Rare male frilled shark discovery expands knowledge of species distribution

In a significant discovery, researchers have confirmed the presence of a male frilled shark, known scientifically as Chlamydoselachus anguineus, off the coast of Chile. This find adds new and valuable information regarding the morphology and distribution of this deep-sea species, which has been rarely documented. Prior to this find, only one other frilled shark had been recorded in Chile, a female caught in 1976. The recent male specimen was caught incidentally in 2015 by a fishing vessel near Cucao, on Chiloé Island, at a depth of approximately 1,640 feet (500 meters). It remained preserved in a private collection until researchers gained access to it in 2023. This capture extends the known range of the species in the southeastern Pacific by nearly 530 miles (850 kilometers) southward. The male frilled shark, noted for its primordial appearance with an elongated and eel-like body, had several unique characteristics highlighted during its examination. Researchers took 48 body measurements to compare this specimen with the previously recorded female and other frilled sharks from different regions. Initial findings indicated that the Chilean male showed differences such as a longer head and smaller pelvic fins relative to its total body length. However, researchers explained that the small sample size limits definitive conclusions about these variations. Additionally, the captured male was assessed to be sexually mature, featuring calcified claspers and developed testes. This is particularly noteworthy since documented mature males of this species are exceedingly rare, with only eight recorded globally. On the other hand, the female shark collected in 1976 could not be evaluated for maturity due to the lack of internal organs in its preserved state. The inability to conduct genetic testing on either specimen is also a setback since the formalin used for preservation breaks down DNA over time. Consequently, understanding the genetic makeup and broader population dynamics of frilled sharks remains a challenge due to insufficient data regarding their population size, structure, and trends. Reports indicate that these sharks are occasionally caught as bycatch in deep-sea fisheries, yet sightings remain rare, enhancing the significance of each recorded encounter. As scientists continue to study the frilled shark's biology and ecology, this discovery opens avenues for future research and contributions to the conservation efforts of marine biodiversity. This confirmation of the frilled shark’s presence in Chilean waters underlines the importance of marine research and highlights the need to protect unique marine species that have survived millions of years. With ongoing studies, researchers hope to gather more data that will illuminate the life cycles and populations of these enigmatic sharks, increasing awareness and understanding of deep-sea ecosystems. By sharing this new information, researchers aim to foster greater scientific inquiry into the frilled shark and similar deep-sea creatures, addressing both their mysteries and conservation needs.