Shark Q&A: What's the Most Bizarre Thing About Chimaeras?

An expert in the field chimes in.

Photo: Pictured is a black ghostshark, a chimaera found in waters off Australia and New Zealand. Credit: Brit Finucci In honor of Shark Week, Discovery News thought it would be fun, in the coming days, to put questions to shark experts. The subject of today's big Q is the boneless, deep-sea-dwelling chimaera, and we asked Brit Finucci to share her thoughts on what's most bizarre about these curious relatives of sharks.

Brit is a Victoria University of Wellington PhD candidate in deep sea chondrichthyan biology and ecology and a member of the Gills Club of women scientists, an organization whose motto is "Smart About Sharks" and strives to foster girls' passion for sharks.

Here's Brit's answer:

"Chimaeras are shark relatives, belonging to the same class (Chondrichthyes) as true sharks, skates, and rays. They are not well studied, partly because most chimaeras are from the deep-sea, but we do know that chimaeras possess characteristics that make them unique from the rest of the cartilaginous fish.

"The most bizarre of these characteristics is probably the additional appendages that male chimaeras have, which are called tenacula (see photo below). There are two of these located above either side of the pelvic fins, and one found on the top of the head! As males mature, the tenacula become calcified and develop sharp little hooks, very similar to the way that male claspers develop. To my knowledge, there are no records of wild chimaeras seen using their tenacula, but captive animals have been documented using tenacula to grasp onto females during mating."

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