Marine Life Society of South Australia Inc

Marine Life Society of South Australia Inc.

Newsletter

March 2007 No. 341

“understanding, enjoying & caring for our oceans”

Next Meeting

This will be the March Meeting and it will be held as usual at the Conservation Centre on the 21st March commencing at 7.30pm. Our guest speaker is Kevin Dixon who will be telling us about his experiences as a hovercraft pilot, including those in the Port River and areas adjacent to Adelaide.

CONTENTS

Pipefish Part 3(Kevin Smith)

Even More Nudibranch Discoveries (Steve Reynolds)

EDITORIAL

So far I have been asked to do talks to various groups in February (Henley Beach Sailing Club), March (Seaton Senior Citizens), April (Yankalilla Leafy Seadragon festival) and October ( Ladies Group at Brighton).

This is a very promising start to the year and I might even be able to sell some of the three boxes of calendars that I still have in my shed.

Since I have signed up for ADSL2+ the uploading of Newsletters has become much easier however I still need articles for the Newsletters. Please could you help me by sending some in.

Kevin Smith gave an excellent talk on the various species of Pipefish found in South Australian waters at our General Meeting in October 2006. Several members missed the talk so Kevin has agreed to let me publish the slides from the talk in a few of our Newsletters.

Of course the additional comments and explanations, questions and video footage cannot be included. However, I hope this will give you some idea as to the identification of the various Pipefish.

This is the third and final part of his talk. Editor

Thank you Kevin for allowing me to use this article.

We wish you well in the future in Western Australia.

You will be missed by all of us in MLSSA.

Please keep in contact.

Even More Nudibranch Discoveries

by Steve Reynolds

I have been kept busy following up on nudibranch identifications for several underwater photographers once again. David Muirhead, for example wanted Bill Rudman from the Sea Slug Forum to ID a nudibranch that he had photographed at Kingscote Jetty, Kangaroo Island on 4^th July 2006. It was found near the bottom of a jetty pile, amongst heavy invertebrate cover at a depth of 4m. The nudibranch’s length was approximately 30mm.

Photographer - David Muirhead, Kingscote jetty,

Doriopsilla carneola

David’s enquiry (with Bill’s response) was posted on the Sea Slug Forum website at -

http://www.seaslugforum.net/display.cfm?id=19034

on 10^th January 2007.

Bill Rudman’s response was as follows: -

“Dear David,

I am pretty sure this is Doriopsilla carneola, which is very variable in colour. It’s nice to see it on a sponge, which may turn out to be its food sponge. Interestingly the white specks on the mantle seem to mimic the white specks on the sponge. It may be a complete coincidence, but may be worth looking out for in the future.
Best wishes, Bill Rudman”

About the same time, I made an enquiry regarding a nudibranch photographed by Paul Macdonald on a night dive at Port Noarlunga on 28^th December 2006. I mainly wanted confirmation of my own belief that the nudibranch was Hypselodoris saintvincentius so that I could add the name to my ongoing list of invertebrates found at Port Noarlunga reef (as per my article in our 2006 MLSSA Journal).

(Hypselodoris saintvincentius is the species of nudibranch found at the Glenelg Blocks by Dennis Hutson and which featured on page 25 of our 2005 Journal in my article titled “More Nudibranch Discoveries”.)

Photographer - Paul Macdonald, Port Noarlunga reef,

Hypselodoris saintvincentius

My enquiry (and Bill Rudman’s response) was posted on the Sea Slug Forum website at -

http://www.seaslugforum.net/display.cfm?id=19105

on 10^th January 2007: -

Bill Rudman agreed that it was Hypselodoris saintvincentius. This confirmation meant that I could add it to my list of invertebrates for Port Noarlunga reef.

The following enquiry from Dennis Hutson (& Bill’s response) was posted on the Sea Slug Forum website at -

http://www.seaslugforum.net/find.cfm?id=14611 .

“Hi Bill,

I found this little creature on a recent dive. The location was just out from the boat ramp of our shipping channel leading into the Port River. This area is known as Outer Harbor (Local waters of Gulf St. Vincent, South Australia). I photographed this nudibranch and, after consulting Neville Coleman's book “1001 Nudibranchs”, I thought it might be Discodoris lilacina. I am only able to go by basic visual characteristics. Is this critter local to my waters?”

(This is the nudibranch featured on page 27 of our 2005 Journal in my article titled “More Nudibranch Discoveries”.

Photographer - Dennis Hutson, Outer Harbor,

Paradoris dubia

Dennis’s nudibranch was photographed on a silty bottom at a depth of 4 metres on 20th August 2005. Its length was 40 mm.

Bill Rudman’s response was as follows: -

“Dear Dennis,

I am too embarassed to say how long this message has been waiting from me to prepare a Fact Sheet on Paradoris dubia. My apologies. Your animal looks like a Discodoris, and in fact has been placed in that genus until Benoit Dayrat’s recent revision of the genus Paradoris. As you may have guessed by now, your animal is Paradoris dubia. It usually has ring-shaped marks on the mantle which are quite distinctive. I have posted a Fact Sheet today. Have a look at that and the accompanying messages I am also posting to show colour variability.

Best wishes, Bill Rudman”

It appears that Paradoris dubia is the former Discodoris dubia. Neville Coleman called this ‘Doubtful Discodoris’ in “1001 Nudibranchs”. Photos of the creature are featured on pages 55-6.

I made another enquiry to the Sea Slug Forum regarding the ‘Flabellina Sp.’ photographed by Paul Macdonald at Port Noarlunga reef on 18th June 2006 (as mentioned in my article “The Marine Life at Port Noarlunga Reef” in our 2006 Journal. Here again is Paul’s photo of the nudibranch from Port Noarlunga which featured on page 10 of our 2006 Journal.

Photographer - Paul Macdonald, Port Noarlunga,

Pteraeolidia ianthina

As it turned out, I was incorrect in suggesting that it was a Flabellina Sp. Below is Bill Rudman’s response

(posted at http://www.seaslugforum.net/find.cfm?id=19208 ): -

“Dear Steve,

This is the a solar-powered sea slug - Pteraeolidia ianthina. Its white colour suggest it has not yet started to farm zooxanthellae in its body, so I presume it is quite young.

Best wishes, Bill Rudman”

At http://www.seaslugforum.net I found the following details about Pteraeolidia ianthina: - “Order: Nudibranchia, Suborder: Aeolidina, Family: Glaucidae, Distribution: Throughout the tropical and subtropical Indo-West Pacific.

SOLAR-POWERED SEA SLUGS

Pteraeolidia ianthina, commonly known as the ‘Blue Dragon’ by divers in eastern Australia, is one of a group of remarkable aeolid nudibranchs which are way ahead of man in harnessing solar energy. Pteraeolidia has evolved a method of capturing and farming microscopic plants (zooxanthellae) in its own body. The plants flourish in this protected environment and as they convert the sun's energy into sugars, they pass a significant proportion on to the nudibranch for its own use.”

And “White juveniles are usually found in lush growths of short “turfing” hydroids, but until now no sign of zooxanthellae has been found in the hydroids. Adults can last some time without feeding, presumably obtaining sufficient nourishment from their zooxanthellae gardens. The large solitary hydroid is the preferred adult food.”

In his book “1001 Nudibranchs” Neville Coleman calls Pteraeolidia ianthina the ‘Serpent Pteraeolidia’. Pages 114-5 features several photos, descriptions and comments. The family name given, however, is Facelinidae.

Dennis Hutson photographed a tiny yellow slug-like creature with a limpet-like shell (also yellow) on its back whilst diving at Port Stanvac Dump in November 2006. We identified it as being the Little Umbrella Shell, Tylodina corticalis, after the dive. We thought that it was a rare sighting but later discovered that other photographers such as Michael Matthewson and David Muirhead had also found specimens. Tylodina corticalis is not a nudibranch though. It is an opisthobranch. Opisthobranchia is a Subclass of gastropod molluscs. Bubble shells, sea hares, side-gilled slugs and nudibranchs are all opisthobranch slugs. Although Tylodina corticalis is classed as a slug, Neville Coleman calls it the Small Umbrella Shell on page 135 of “1001 Nudibranchs”. Details about this species will be the subject of a separate article.

Photographer - Dennis Hutson, Port Stanvac Dump,

Tylodina corticalis

REFERENCES:

“The Marine Life at Port Noarlunga Reef” by Steve Reynolds, MLSSA Journal No.16, December 2006.

“More Nudibranch Discoveries” by Steve Reynolds, MLSSA Journal No.15, December 2005.

“1001 Nudibranchs” by Neville Coleman, Underwater Geographic P/L, 2001, ISBN 0947325255 – mlssa No.1050.

The Sea Slug Forum website at http://www.seaslugforum.net