In the vast ocean, mating can be a challenge for limbless fish. However, the ratfish has a unique strategy. The male ratfish possesses a specialized forehead appendage called a tenaculum, equipped with teeth, allowing it to grasp onto the female’s fin during mating.
Recent research has revealed that these teeth-lined appendages defy previous assumptions that they were covered in spiny scales like those found on sharks and rays. Marine biologist Karly Cohen from the University of Washington explained that these teeth are similar to the ones found in human and animal mouths.
Published in the Proceedings of the National Academy of Sciences, the study sheds new light on deep-sea creatures and challenges the conventional belief that teeth only develop in the mouth.
Ratfish are mesmerizing deep-sea creatures belonging to the chimaera group, distinct from sharks, with shimmering bodies and luminous green eyes. The study focused on spotted ratfish, abundant in Puget Sound waters off Washington state, where researchers observed and analyzed specimens using micro-CT scans.
The tenaculum of the male ratfish was discovered to contain rows of shark-like teeth embedded in a unique tissue structure known as the dental lamina, a feature previously only observed in jaw structures of animals. These findings intrigued Aaron LeBlanc, a paleontologist from King’s College London, who emphasized the novelty of the discovery.
Despite these revelations, many mysteries remain regarding the evolution and purpose of the ratfish’s forehead teeth. Researchers ponder whether these teeth initially served a defensive role or evolved solely for mating purposes.
Interestingly, fossil records of Helodus simplex, a prehistoric chimaera, exhibited a similar toothy appendage near its nose, resembling the ratfish’s tenaculum. Female ratfish were also found to possess small structures akin to male juveniles but never developed them fully, raising questions about their purpose.
Marine biologist Milton Love from the University of California’s Marine Science Institute expressed fascination with the ratfish’s mating behavior, comparing it to other species’ mating rituals involving neck biting. Love marveled at nature’s wonders, emphasizing the charm in discovering such unique adaptations.