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Describing a new species of shark happens occasionally but describing a whole new family of sharks is super rare! Yet CSIRO researchers Will White and Helen O’Neill, with other scientists, have recently done it.

The new family of deep-water catsharks is called Dichichthyidae (pronounced ‘Die-kick-thee-iday’) or the Bristle Sharks. Their common name comes from their ‘bristle-like’ denticles. Denticles are microscopic teeth-like structures found all over their head, body and fins.

Four sharks, originally placed in a different catshark family, were moved into Dichichthyidae. But what led to the scientists to create a new family? They found differences in these sharks’ skeletons (particularly the skull) and body morphology (like the fin shapes). Bristle Sharks also have a very unique egg case. These cases have a banana-like curve and a dense matting of fibres on a ridged surface.

One species moved into the Dichichthyidae family is the Beige Bristle Shark (Dichichthys bigus). Found in Australia, this shark is only known from the holotype (the specimen used to describe the species). But, in 2020 it was filmed by the ROV SuBastian at a depth of ~840 metres during a Schmidt Ocean voyage in the Coral Sea.

Will and Helen’s team also described a brand-new species belonging to the Dichichthyidae family. The Roughback Bristle Shark (Dichichthys satoi) is from northern New Zealand. These catsharks are found at depths of 666–1175 metres.

Although published only two month ago, the taxonomy (scientific description) of this shark family took a long time. “A researcher first recognised the uniqueness of this group of sharks over a decade ago,” said Will White. “It has taken until now to collect the data required to resolve the taxonomy of this unique group of sharks.”