Otinodoris sp.

Image courtesy of Dave Mullins
4 metres, in the Lawadi muck, Milne Bay, PNG
Sony DSC-RX100 in Nauticam Housing with wet macro diopter, Inon Z220 strobe.

Otinodoris sp. (undescribed)

Milne Bay, PNG has proved to be a rich source of new or unusual species of sea slug. The Webmaster and I were there recently and examining, very closely, the substrate at Lawadi for tiny specimens to record for posterity when this hand-sized beauty was spotted out in the open undulating across the silt and rocks. I swooped in and took some quick pics including a couple of its ventral surface before the Webmaster settled in to take some glorious video of it on the move.

I will admit that my initial thoughts as I continued the dive, especially with those distinctive ventral markings in mind, was of Platydoris. However on closer examination the mantle surface can be seen to be covered in long branching papillae. These are so obvious in the Webmaster's video wafting back and forth as the slug makes its way forward.

Terry Gosliner kindly came to the rescue suggesting it is a species of Otinodoris and remarking that it looks quite similar to Otinodoris raripilosa. It may be that species or an undescribed one but relying on a photograph to identify some of these Discodorididae is fraught with danger. (See page 182 of the new Nudibranch and Sea Slug Identification: Indo-Pacific book by Gosliner, Valdes & Behrens).

Note the ventral colouration and patterning and also those large flattened oral tentacles. The Discodorididae features of a notched upper lip and the bilabiate anterior foot are also observable.

Sometimes it's so nice to take off the macro lens and still have a sea slug fill the viewfinder.

WEBMASTER'S NOTES: I'll drink to that!

Dave Mullins
Queensland, Australia
December 2015
Send Dave email at marineimages@hotmail.com

Dave Mullins on location

WEBMASTER'S NOTES: Dave has been active in underwater photography since the early 70's and is presently the Webmaster/Publisher of Insights , a web site you definitely should put on your list of sites to visit!

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