October-December 2020 PODs

Bill’s “Pictures of the Day”

from October to December 2020

Spanish Shawl on the lava stage (thanks Dana) form our dive last weekend at the "poo pipe”.

Here is an Acanthadoris hudsoni (I think) from our dive at the pipe last weekend. This guy is on a black felt stage. The goal of the stage is to make only the nudibranch the subject of what you see (not like the lava stage). To do this you need some really black stuff. The blackest black stuff that you can buy is VantaBlack (but you can only buy it if you are Anish Kapoor). Vantablack absorbs 99.96% of all light. It is really black. Sadly though you can't use it in water. The telescope guys are the ones most interested in obliterating stray light and they have tested a wide variety of felt materials to put in the tube of a telescope. This stage is made using one really good felt from Protostar. Even with that, levels adjustment in Photoshop is necessary to get the black as dark as it is (5,9,9) in RGB space.

Another Acanthodoris hudsoni on the lava stage.

Last weekend we dove PV with friends on the Giant Stride. The conditions were not quite as nice as the week before but still got some nice nudibranch action. Here is a nice little A. lutea sitting on a brand new dichroic stage; the glass is made using a different technique.

Our friend and dive buddy Kevin Lee gave me this rock that came from near the summit of Mt. Baldy. Here a nice little lutea is climbing over the edge.

Here is an unknown to me nudibranch on a dichroic stage (new version). Looks like albopunctata but the gills are not white but rather orange.

Here is a nice little Polycera tricolor scaling the summit of Mt Baldy.

And now for something completely different as Monty Python says. Here is a nice little tricolor sitting on a blue reflective (not dichroic) stage shot with my homemade square swirl tube or as I call it the fun house mirror. Enjoy (or not).

From our most recent local dives. Here is a tiny baby Hermissenda shot with the square swirl tubes. I don't understand why the reflections look this way but enjoy.

Here is a nice little Tritonia, this one sitting on the lava stage.

Here is another rhodoceras this time sitting on the cielo (heaven) stage. This is actually the backside of a blue dichroic glass (the dichroic coating is only on one side).

Here is a nice little Hermissenda sitting on the black telescope felt stage.

Here is a nice little (2 inches) Pseudoceros luteus a flatworm we found on our dive yesterday on the Giant Stride with our friends. This one is on the telescope felt stage and was shot at the White Point outflow pipe.

Last one for today from our dive yesterday on the Giant Stride. Here is a nice little Spanish Shawl sitting on the telescope felt stage.

Here is a nice little Polycera hedgpethi (named after Joel Hedgpeth, a California slug and sea spider guy). This species is mostly found in the Mediterranian and Atlantic and some consider him an invasive species in California. In the immortal words about Jimmy Buffet's new tattoo, how it got here we haven't a clue. This guy is sitting on the stage covered with the black telescope felt. Thank you Dana for bringing him over.

Here is a nice little clown (Triopha) nudibranch sitting on the black felt stage. These guys have been studied extensively to determine how their brain chemistry works. It turns out that the Triopha have significantly the same serotonin reactive segments in their brains as the Tritonia, Hermissenda, and Janolus, strongly suggesting that they have a common ancestor.

Here is a nice little Antiopella from our dive last weekend. To me these will always be Janolus but I guess Terry Gosliner had a PhD student that needed to do some work on this guy. He was sitting on the telescope black felt, and we saw him at Biodome. Thanks to Nannette for finding him.

Here is a nice little Tritonia festiva sitting on the orange dichroic glass stage from our recent dive on the Giant Stride with friends.

Here is a different guy (probably—this was a week after the previous dive) sitting on the black telescope felt stage.  These Tritonia are very interesting guys. The thing that looks like a mustache is their digitate frontal veil. It’s extremely sensitive and used for locating expanded polyps of their prey and for carefully positioning the mouth over these in preparation for a surprise attack. The ensuing attack is swift, as the nudibranch lunges into the colony and bites off polyps before they can contract into the protective cover of the spiculate colony mass. Tritonia festiva will not attack contracted colonies, and severed polyps are eventually regenerated by all but the smallest octocoral colonies. They are vicious predators and will all types of octocoral on the reef.

Another clown nudibranch on the black telescope felt.

Here is a nice little H. opalescens from our dive yesterday with friends on the Giant Stride. Here he is sitting on a black felt stage. This is not the telescope felt but rather some from McMaster that to the eye looks blacker than even the telescope stuff. These are interesting nudibranchs that have been used in the lab for a wide variety of experiments on sensory stimulus. For example Subcellular, cellular, and circuit mechanisms underlying classical conditioning in Hermissenda crassicornis. This guy apparently has only one cephalic tentacle.

Here is another species named after Stearns, Paracyathus stearnsii. This one a little (quarter size) cup coral on the poo pipe.

Here is a nice little (and by little I mean little) Podocerus cristatus from our recent dive on the Giant Stride with friends.

Males locate potential partners with the aid of their antenna to detect the pheromones released by the females; the male then rides or carries the female until the latter is ready to molt; when the female molts the male will inject sperm. The whole pregnancy lasts a few days. Personally I think riding sounds like more fun than carrying but I am not an amphipod.

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