Not quite a megalodon, but a new species of deep-ocean shark at just 5.5 inches long (about 144 mm) and somewhat smaller than the prehistoric super-predator.

>>“The fact that only one pocket shark has ever been reported from the Gulf of Mexico, and that it is a new species, underscores how little we know about the Gulf – especially its deeper waters – and how many additional new species from these waters await discovery,” says Bart, director of Tulane’s Biodiversity Research Institute.<<

https://newatlas.com/new-species-pocket-shark/60674/

PermeateFree said:

Not quite a megalodon, but a new species of deep-ocean shark at just 5.5 inches long (about 144 mm) and somewhat smaller than the prehistoric super-predator.

>>“The fact that only one pocket shark has ever been reported from the Gulf of Mexico, and that it is a new species, underscores how little we know about the Gulf – especially its deeper waters – and how many additional new species from these waters await discovery,” says Bart, director of Tulane’s Biodiversity Research Institute.<<

https://newatlas.com/new-species-pocket-shark/60674/

That’s tiny for a shark. I’ll look at my spreadsheet of shark lenghts later, but IIRC a typical shark length is 1 metre and there aren’t all that many known shorter than 300 mm.

One specimen each for the two species, Hmm.

New shark species are being found at a startling rate, with new species almost every year if not more often. It’s even possible IMHO that we’ve only found 50% of the world’s shark species.

I can’t help wondering about the influence of geographic isolation in the deep ocean on the evolution of new species. Perhaps the undersea valleys on the edges of continental shelves about 440 meters deep act as uniquely different ecosystems. That’s just a wild hypothesis, no proof.

How do you determine if a species is threatened from only one specimen? I would assume that it is, unless proved otherwise. But the Red Book just says “not enough data”. What do you say?

mollwollfumble said:

PermeateFree said:

Not quite a megalodon, but a new species of deep-ocean shark at just 5.5 inches long (about 144 mm) and somewhat smaller than the prehistoric super-predator.

>>“The fact that only one pocket shark has ever been reported from the Gulf of Mexico, and that it is a new species, underscores how little we know about the Gulf – especially its deeper waters – and how many additional new species from these waters await discovery,” says Bart, director of Tulane’s Biodiversity Research Institute.<<

https://newatlas.com/new-species-pocket-shark/60674/

That’s tiny for a shark. I’ll look at my spreadsheet of shark lenghts later, but IIRC a typical shark length is 1 metre and there aren’t all that many known shorter than 300 mm.

One specimen each for the two species, Hmm.

New shark species are being found at a startling rate, with new species almost every year if not more often. It’s even possible IMHO that we’ve only found 50% of the world’s shark species.

I can’t help wondering about the influence of geographic isolation in the deep ocean on the evolution of new species. Perhaps the undersea valleys on the edges of continental shelves about 440 meters deep act as uniquely different ecosystems. That’s just a wild hypothesis, no proof.

How do you determine if a species is threatened from only one specimen? I would assume that it is, unless proved otherwise. But the Red Book just says “not enough data”. What do you say?

Does it mentioned that it is threatened? Clearly as you say not enough data to determine much at all, other than the actual fish and where it was found. Animals generally prefer a specific habitat and many species will not be found outside a narrow range; it also applies to plants, etc., and why new species are usually discovered these days in unique or difficult to reach environments.

Some additional information:

This New Shark Species Looks Like a Tiny Sperm Whale
The 5.5-inch-long Mollisquama mississippiensis—one of only two pocket shark specimens known to science—also glows in the dark

Published in the journal Zootaxa, the paper describes an unusual shark that was discovered during a scientific survey of the Gulf of Mexico, while scientists were researching the feeding behaviors of sperm whales. The researchers used sonar to track the whales as they dove to 3,000 feet, then used nets to drag up prey from the area. Among those samples was a male pocket shark, which was frozen for later analysis.

The new specimen has 10 fewer vertebrae than Mollisquama parini. And in contrast to Mollisquama parini, it has a pit organ—which may help sharks detect stimuli, like water currents—on its jaw, and light-producing organs known as photophores distributed irregularly around its body. Photophores are known to exist on other sharks, and according to the study authors, these organs “may facilitate predatory behavior and render practically invisible from below.”

https://www.smithsonianmag.com/smart-news/new-shark-species-looks-like-tiny-sperm-whale-180972704/