A weird little hydroid

Posted on March 14, 2024 by An Bollenessor under cnidarians, hydroids, Hydrozoa, Macro

This is a weird little hydroid and so only has a Latin name to go by: Candelabrum cocksii. It was first described by Cocks in his ‘Contributions to the fauna of Falmouth’ in the 1850s and it is quite common locally. I find them mostly as pictured here, but sometimes I see them with their foot extended, going from a centimetre to 8 centimetres or so in length. This allows them to rove over the rock surface in search of tiny (crustacean) prey. Their mouth is located at the end of the trunk which is covered in ‘capitate’ tentacles (see the pic below for anatomical labels). The white spheres are gonophores used for reproduction. It should be possible in summer when these hermaphrodites reproduce to see dedicated clasper tentacles holding the embryos, that would be cool (to me at least!). Btw, I remembered I posted about this species not even that long ago! See here and also see this link and this link from fellow enthusiasts across the pond who likewise have been fascinated by Candelabrum.

Candelabrum cocksii

Posted on January 7, 2022 by An Bollenessor under Hydrozoa, Macro, molluscs

It was a nice day and a good low tide last Wednesday and so I decided to go for a snorkel; I was glad I did! Last year, I had been trying to take photos of this weird little animal, Candelabrum cocksii, but failed miserably, this time it worked. It is a hydrozoan that was first described in Victorian times on the exact beach I always go snorkelling here in Falmouth. It is tiny (see last pic) and lives underneath rocks, so it goes mostly unnoticed (and therefore does not have a common name). To take this photo, I had to do some ‘underwater rockpooling’, turning over a rock to find them. I am not sure what the deal is with these guys; I know the white bulbous structures at the bottom are reproductive structures, and the reddish bit at the top is for feeding (this bit can be stretched out quite a lot). It is colonial just like the Portuguese Man O’War. Please correct me if I am wrong hydrozoan experts! Shout out to David Fenwick and his ID site aphotomarine.com, which I highly recommend.

Other notable finds were stalked jellyfish Calvadosia cruxmelitensis and my very first Wentletrap (which is a Dutch word: wenteltrap=spiral staircase) Epitonium clathrus. As I had my macrolens on the camera I could not shoot any general impressions but the pools started to look beautiful again. The big Wireweed and Thong weed plants were all gone (new ones emerging) and the red seaweeds (Sphaerococcus, Plocamium, Chylocladia) were already quite big.

It was great to be back in the water today and it is my New Year’s resolution to spend a lot more time underwater than I did in 2021! Who knows I will even learn how to use strobes. A happy 2022 to all blog readers!

More Macro

Posted on March 14, 2019 by An Bollenessor under anemones, crustaceans, echinoderms, fish, Macro, Olympus OM-D E-M5 Mark II, rock pooling

These photos are from a couple of weeks back; since the weather has been hideous most of the time I have not been out much since. More practice with the m.zuiko 60mm macro lens abovewater. Above a small Strawberry anemone. Below a small Cushion star Asterina gibbosa and my finger tip for size. Below that the hydroid Candelabrum cocksii and an Idotoea isopod species (there are several common Idotoea species but I have not paid much attention to them yet I must admit). Finally, the adorable Worm pipefish Nerophis lumbriciformis which is common and usually found in small groups under rocks (I have never seen them underwater as they are small, slow, well-camouflaged and probably hidden most of the time). Definitely will try to get some more portraits of these lovely fish!

random rock pool pics

Posted on March 10, 2016 by An Bollenessor under anemones, cnidarians, crustaceans, echinoderms, fish, molluscs, rock pooling, worms

The weather has been generally awful so far this year and so I have not been out much. However it is March already so at least a small blog post is in order! There are loads of Worm pipefish Nerophis lumbriciformis around, some of the males carrying eggs (see also the blog header and the ‘about’ section). I found my smallest one yet. Next up a Sea urchin Psammechinus miliaris with what is probably the parasitic (or commensal?) polychaete worm Flabelligera affinis (thanks David Fenwick). After that, a slighlty out of focus shot of the hydroid Candelabrum cocksii. A few of these small individuals were sat under the first rock I turned over; I reckoned they were some type of spoon worm but they are something very different, thanks again David Fenwick, see for his much better photographs of this weird little thing here. Next the Wrinkled rock borer Hiatella arctica with siphon extended and the pretty acorn barnacle Balanus perforatus. Finally a picture of the Strawberry anemone Actinia fragacea, quite common and pretty, but I do not think I have ever posted a picture of it on the blog before. (All pics taken at Castle Beach in Falmouth btw.) I have three in my tank and it is high time for an aquarium update as well. I hope to go out tomorrow and the weekend as the tides are very low so watch this space!