UNDERRATED CHONDRICHTHYAN 2020: Anna’s six-gilled sawshark

The Fins United Initiative is excited to bring back the loved "Underrated Elasmobranch Spotlight" series through TFUI officer Jess Myers. Learn about the Chondrichthyans not shown on the big screen through her beautiful artwork!
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As we’ve seen in 2018’s Underrated Elasmobranch lineup, the broadnose sevengill shark (Notorhynchus cepedianus) didn’t follow typical shark anatomy. Today’s shark doesn’t either. This shark has 6 gill slits and a saw shaped rostrum (saw) - for those reasons it’s called Anna’s six-gilled sawshark (Pliotrema annae). This shark, along with another species of sixgilled sawshark, were discovered this year, making for a total of 3 sixgilled sawshark species!

 How often do you think new species are discovered? You may be shocked to know that scientists unveil about one new species of elasmobranch every two weeks! New species may often look like ones we have previously discovered, but sometimes it can only take one small detail and a (sometimes heated) conference between taxonomists to decide if a specimen should be considered a new species. With the recently discovered sixgilled sawsharks, the determining factor was the placement of along the rostrum.

This new species was found off of Zanzibar. Since it is so new, we don’t know its full distribution or it’s conservation status. It likely faces similar issues as other saw sharks that get easily tangled in trawl nets where they are unable to move or eat. They are not caught for food, so any sawshark that comes up is treated as bycatch.
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 Last little thing… I couldn’t find this in my searches, but who do you think the shark was named after?


Reference image and information from Weigmann et al. (2020) Revision of the sixgill sawsharks, genus Pliotrema (Chondrichthyes, Pristiophoriformes), with descriptions of two new species and a redescription of P. warren. 

WHAT UNDERRATED CHONDRICHTHYAN DO YOU THINK SHARK WEEK SHOULD SHOWCASE?

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