Cerratapalooza - Observation of the Week, 8/24/21

Our Observation of the Week is this Cockscomb Nudibranch (Antiopella barbarensis), seen in the United States by @helgeweissig.

“While I was SCUBA certified in 1994, I have only recently begun to dive regularly and a couple of years ago I started taking my photography hobby with me under water,” says Helge Weissig. “I have become increasingly interested in nudibranchs and other invertebrates but sometimes the odd fish picture will sneak into the mix.”

Helge went diving at “the wall” off La Jolla Shores in southern California last November and spotted quite a few creatures, including several cockscomb nudibranchs.

At the wall, the gentle slope of the Shores takes a steep step down from about 50 ft to up to 65 or 70 ft before dropping off more gently again into the depths of La Jolla Canyon. There is typically a lot of life on older sections of the wall (it crumbles from time to time, exposing naked clay that often stays barren for a while) and on that particular day, I found two Cockscombs [the other below]…

Cockscomb nudibranchs are probably some of the most luminous creatures one will find under water in Southern California. They are not exactly rare but most often solitary and easy to miss. Their bulbous cerrata (those club-shaped appendages on their body) often feature neon-blue tips and yellow rings while their rhinophores (the two antenna-looking appendages in the front) are light blue but often hidden or retracted.

Helge (above) tells me that by the time he was a teenager he knew he wanted to be a biologist, which led him from his home in rural Germany to San Diego. However, he eventually changed his focus to molecular biology and genetics and for the past nineteen years has “been working at an early drug discovery research and biotech company maintaining their research informatics platforms and running all sorts of data analyses.”

He only started using iNat recently but says he’s “very much hooked already.”

The ease of uploading and labeling observations as well as the very collaborative nature of identifying all kinds of organisms make it a fantastic tool for sharing observations, learning about their nature, and connecting with other people interested in and knowledgeable about them. While I mostly focus on the esthetics of my underwater photographs, I will continue using iNat to help me identify those organisms I haven’t encountered before and have not found information on anywhere else.

(Photo of Helge by Volker Kilian)

- as @anudibranchmom noted on the observation itself, the cockscomb nudibranch up top, lacking blue tips on its cerrata, looks quite similar to a tunicate colony, eg https://www.inaturalist.org/observations/55117299

- Take a gander at the most-faved nudibranchs on iNat!

Posted on Αύγουστος 24, 2021 0941 ΜΜ by tiwane