Hydatina physis

Image courtesy of Jim Black
Anilao, Philippines
Nikon D-300 in Subal Housing with Ikelite strobes.
Copyright 2011, Jim Black

Carolus Linnaeus by Hendrik Hollander,1853

Hydatina physis (Linnaeus, 1758)

Hydatina physis is one of the oldest opisthobranchs ever named for science. It is truly one of the original sea slug "New Species." Carolus Linnaeus had only published his foundation monograph defining his system of natural classification of all living things based upon a hierarchy "Systema Natvrae" in 1735. Just 23 years later he's naming sea slugs. And, he named several 100's. Darn -- he was more prolific than my good buddy - Angel Valdes.

This very large bubble snail has a pinkish body with a white marginal band. Its retained shell has numerous thin black spiral lines.

This head shield slug feeds on cirratulid polychaete worms, on soft bottoms. The slug then synthesizes chemicals from the worm into toxic substances it uses in its own defense.

This species is circumtropical. In the Indo-Pacific it occurs from South Africa and the Red Sea to Guam and the Hawai'ian Islands.

Want to know more about the "naming of species"and Linnaeus' rules - see my article in California Diver, May-June issue with photos by Kevin Lee.

A short video of Hydatina physis with egg mass taken by the Webmaster is also available for the enjoyment of our readers!

Dave Behrens
Gig Harbor, Washington
Jun, 2011

Jim Black on location in Thailand with friend

Jim is retired from US Airways after 27 years as a pilot..., flying Captain on an Airbus 330 Internationally.

Diving since 1970...with over 5200 dives logged. Shoots Nikon D-300 in Subal Housing with Ikelite strobes. Macro Mate on 105mm for supermacro.

Jim's photography has been featured in a number of books and publications including Helmut Debelius' Nudibranchs and Sea Snails of Gosliner, Behrens and Williams Coral Reef Animals of the Indo-Pacific. A photo of Jim petting a shark in "Sleeping Shark Caves" off Isla Mujeres Island, Mexico, taken by Amy Foster his significant other, recently appeared in Dave Behrens' Diving Guide to Cozumel, Cancun & The Riviera Maja.

Jim has been a solid supporter of the Slug Site since day one. His countless contributions put him near the top of the list of photographers who have greatly expanded our knowledge of sea slugs. There are a lot of kids in the formative stage of their education who are getting their first introduction to our sea slug friends via the great photographs Jim and other contributors have made to the site. My hat is off to Jim for making this presentation possible!

As an added note, Jim was one of the keynote speakers at the Pittsburgh Scubapalooza, held Saturday, 5/14 at the Pittsburgh Scuba Center, 818 Ann St., Homestead, Pa.

Send Jim email at jim.black14@verizon.net

WEBMASTER'S NOTES : Another great submission by Jim Black who continues to astound us with his uncanny ability to find and photograph slug images most of us probably aren't going to see in this lifetime!

From left to right, Terry Gosliner, Angle Valdes, Dave Behrens La Jolla, Calif.

Send Dave email at davidwbehrens@gmail.com

© The Slug Site, Michael D. Miller 2011. All Rights Reserved.