Okenia stellata

Image courtesy of Ali Hermosillo McKowen
Milne Bay, PNG
Dec. 2019

Okenia stellata Rudman, 2004

I have always loved Okenia's but have never understood the aeolid-wanna-be body morphology. Do the club shaped lateral processes increase the respiratory surface area of the body, thereby acting like secondary gills? I really don't know.

Bill Rudman named Okenia stellata for the star-like arrangement of the lateral papillae. This species has similarities to Okenia nakamotoensis (Hamatani, 2001), which also has 5 pairs of lateral papillae, but they are shorter and the tips are swollen with a rounded point.

The body is white to pink, with red tips on the lateral processes and rhinophores. There is a pattern of thin red lines on the dorsum, including a ring around the body just below the papillae, which is usually partly hidden from above by the lateral papillae. There are also two lines on the dorsum which run from the behind each rhinophore back.

The shape of the radular teeth is very unusual for the Goniodorididae. We will not be describing it here, but suggest you go to this link - Sea Slug Forum on Okenia stellata for an SEM of the radula.

This species is found on its food source, a branching, erect, calcareous bryozoan, Pleurotoichus clathratus.

Dave Behrens
Sammamish, WA 98074
Jan., 2020
Send Dave email at davidwbehrens@gmail.com

Ali Hermosillo on location in the Philippines

Ali needs very little in the way of introduction to readers of this site. She has been featured in many of the Branch of the Week (BOW) presentations through the years. Diving with Ali can be infectious assuming you can keep up with her. If you didn't have an appreciation for our friends the sea slugs before diving with her, you will certainly reach quantum levels in that regard as Ali is all consuming in her quest to photograph and document their behavior! In the last few years she even acquired her Doctorate in Opistobrach Studies so her enthusiasm certainly knows no bounds. She has the material for putting together field guides for both the Milne Bay region of PNG and also Anilao in the Batangas area of the Philippines. Let's encourage her when time permits to make that happen!

As a side note Ali has posted ID's with her Flicker postings from both areas. The links can be seen in the left frame of this site. Very worth while to visit for those who are seeking to put names together with images.

What more can be said, Ali is the greatest!

Send Ali email at aliciahmckowen@gmail.com

Michael Miller
San Diego, Calif
Jan., 2020
Send Mike email at mdmiller1@cox.net

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

Send Dave email at davidwbehrens@gmail.com

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