First of all, nudibranchs are tiny, and I love macrophotography!
Photographing small marine creatures was my goal when I dove off the island of Oahu in Hawai’i. I was on the trip by myself, so I made sure to have a dive master who could show me around the local underwater landscape. He was quick to point out turtles, an octopus, and a long-spined crown-of-thorns, but I was looking for something smaller.
Towards the first half of the second dive (of a two-dive trip), he pointed out the first nudibranch. I was elated to see this tiny gem of the ocean. For me, nudibranchs are one of the most exciting things to see while diving. I have a few reasons. First of all, they are tiny, and I love macrophotography. Two, they come in vibrant colors and body shapes. Lastly, there is little known about them, so it gives me an opportunity to learn as much as I can!
This photo is of a varicose wart slug. Its scientific name is Phyllidia varicose. It belongs to the family Phyllidiidae. For a nudibranch, they are quite large. They can grow to be almost 4.5 inches long. This one was about two inches. The varicose wart slug will grow between three and six longitudinal, tuberculate notal ridges. Let me break that one down for you. Longitudinal means running from its head to its rear. Tuberculate describes the small rounded projections coming off the ridge. Notal refers to the fact that the ridges are along the back. A synonym would be dorsal. Each of these “warts” are yellow over a blue-grey mound. Between each mound, this nudibranch is black.
Although the rhinophore, which is a rod-shaped structure protruding from most sea slugs, is not visible in this photo; the varicose wart slug has a quite complex rhinophore. The clavus, which is at the end of the stalk, can have between 27 and 30 lamellae. The lamellae are ridges or folds that cover the ends of the rhinophore.
The clavus, which is at the end of the stalk, can have between 27 and 30 lamellae
Did you know?
- The sea cucumber, Pearsonothuria graeffei, will mimic the varicose wart slug as a juvenile. They try to use the warning colors that this nudibranch has to convince predators that they would be toxic like the nudibranch.
- The rhinophores of this nudibranch can be retracted.
- Varicose wart slugs are hermaphroditic with two female opening and one male opening. This is referred to as a triaulic reproductive system.
- They are most commonly observed feeding on sponges in the genus Hymeniacidon.
0 Comments