Order: Sorbeoconcha (Neotaenioglossa)
Trivia californica feeding on tunicate. San Miguel Island, Channel Islands National Park, California - July 2003. Photo: Bruce Wight
Triviids have usually been considered relatives of the cowries [Fam: Cypraeidae] but are in fact more closely related to the Velutinidae also known as the Lamellariidae. The inflated cowry-like shell is at least partially enveloped by fleshy mantle lobes, which can give them a fleshy shell-less appearance which often causes them to be mistaken for sea slugs. In most cases when they are crawling a pair of head tentacles will emerge from beneath the body, with basal eyes, instantly showing that these are not opisthobranch sea slugs. Another character is the single anterior siphon above the head which opens into the mantle cavity. Velutinoideans all seem to feed on colonial ascidians.Authorship details
Rudman, W.B., 2003 (August 3) Triviidae. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/triviidae
December 5, 2006
From: Dave Behrens
Concerning message #18710:
You are absolutely correct. Trivia solandri has a clear area at the top of the shell.
The classic work Marine Shells of Southern California by James McLean (1978) clearly presents the shells of both species and uses the earliest name Trivia californiana (Gray, 1827). Trivia californica (Sowerby 1832) is a later synonym, not a different species.
email@example.comBehrens, D.W., 2006 (Dec 5) Re: Trivia californica vs Trivia solandri. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/18907
Thanks for clearing that up - so we should be calling it T. californiana not T. californica.
December 4, 2006
From: Kevin Lee
Concerning message #16868:
To augment Bruce Wight's post in June, I have been meaning to share these images of Trivia solandri and Trivia californica, which I erroneously thought were opistobranchs, when I first sighted them. If memory serves correctly, I believe the shell lines do not cross the midrib in the case of T. solandri; whereas the lines do cross in the case of T. californica.
Locality: A: Trivia solandri, Long Point, Catalina, 30 Maech 2005. B: T. solandri, Diver's Cove, Laguna Beach, 22 April 2005. C: californica, Outer Reef, Cress St., Laguna, Beach 05 February 2005.. All approx. 20 feet, all California, USA, Eastern Pacific, rocky reefs. Length: 1.5~2.0 cm. Photographer: Kevin Lee.
firstname.lastname@example.orgKevin Lee, 2006 (Dec 4) Re: Trivia californica vs Trivia solandri. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/18710
Thanks for these photos - but I know I shouldn't really delve deeply into snails, with so many unanswered sea slug messages. Breaking my own rules I decided to check your lines crossing / not crossing definition by a quick Google search and found that in T. solandri the lines don't seem to cross but that there is a complete confusion between T. californica Sowerby, 1832 and T. californiana J.E. Gray, 1827, often with the same image appearing under both names and images of shells with ridges crossing, not crossing, and partially crossing. I don't want to get caught up in a Trivia id exercise but it would be nice if someone could clarify if we have photos of T. californica or T. californiana.
June 15, 2006
From: Bruce Wight
Concerning message #16779:
The reason this photo looks a little different is because it is of a different species, this is not Trivia californica it is Trivia solandri. This species can be identified by the large usually white lobes along the manlt line. It is also larger califonica is usually less than 1/2 inch overall where as solandri is usually between 1/2" to 1". See attached for two images I shot in southern California of T. solandri.
email@example.comWight, B., 2006 (Jun 15) Re: Trivia californica, Channel Islands, California. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/16868
Yes, you are absolutely right. The critter is Trivia solandri. This was also pointed out to me by John Moore. I did not even comment on the identification as it did not seem relevent to Mike's question, nor to the subject matter of the forum. That said - it is important to keep the facts and species names accurate on the WWW.
June 12, 2006
From: Mike Neubig
Note added 15 June 2006: This is Trivia solandri [see message #16868]
Sadly, one of the most beautiful molluscs to ply our waters rates only 614 hits on google this evening, and the google image resource indexes only three photos. On the other hand, your Sea Slug Forum page is top ranked! I could not tell what this beauty was up to when I came across her corporally withdrawn, save a fully extended mantle. It was one of two night dives, and the only Trivia sighting in 9 dives. The tubercles and coloration are much more pronounced compared to Bruce Wight's remarkable photos of Trivia feeding [#10646 ]. Many of the tubercles here bifurcate before termination.
Locality: Santa Cruz Island, Channel Islands, 7m, California, US, Eastern Pacific Ocean, 28 May 2006, underwater talus slope at the base of a 100m vertical cliff. Length: 2cm. Photographer: Mike Neubig.
firstname.lastname@example.orgNeubig, M, 2006 (Jun 12) Trivia californica, Channel Islands, California. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/16779
Well what can we say, Bill and the Museum have done a wonderful job of providing a rapid and efficient access to opisthobranch information and deserve NUMBER ONE on Google. I love it.
Concerning Trivia, it is a gorgeous California species, but it does not really fall under the content of this Forum. Trivia is slug-like but not a sea slug. It is a marine snail [Fam: Triviidae ]. I will admit the mantle resembles that of a nudibranch, but it is only a sheath to cover the shell and keep it smooth, glossy and free on encrusting organisms.
Many tropical relatives of Trivia have elaborate mantles that make them very hard to differentiate from a sea slug. Their colors and mantle morphology are quite spectacular, making them photogenic equals to our buddies the slugs.
Thanks for the great shots and comments,
August 5, 2003
From: Bruce Wight
Johanna and I saw lots of great natural behavior on last weekends dive trip out to San Miguel Island [Channel Islands National Park, California - July 2003]. Here is one of a series of messages showing some images I took during the two day trip.
This is a beautiful Trivia californica feeding on some type of sponge or tunicate.
email@example.comWight, B., 2003 (Aug 5) Trivia californica from the Channel Ids, California. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/10646
Thanks for this great photo of Trivia. Although not a sea-slug it is certainly one of those 'snail groups' which get mistaken for slugs because they hide their shells so well. I have labelled a copy of your photo to illustrate a couple of the characteristic differences between opisthobranchs and other caenogastropod 'marine snails'. Firstly the eyes are associated with the head tentacles, on raised basal 'tubercle'. In opisthobranchs the eyes are always embedded in the skin or body wall. The second difference is the single median anterior siphon developed from a fold in the mantle. Opisthobranchs have no equivalent structure, although some groups have developed paired enrolled head tentacles to serve a similar function.