Life Photo Meme: Lacy

Kingdom: Animalia

Phylum: Ectoprocta (Bryozoa)

Class: Gymnolaemata

Order: Cheilostomata

Family: Reteporidae

When I saw that this week's theme was lacy, I immediately thought of a lacy bryozoan (Phidolopora sp.). And you have to admit it does look pretty lacy. But most people would be hard pressed to identify what it actually is. Bryozoans are colonial animals like corals; but unlike most corals they have to capture their food rather than relaying on photosynthetic symbionts to make it for them.

They are not related to corals, as they lack the stinging cells that all coral posses. They are not closely related to anything existent, but are thought to be distantly related to brachiopods (those clam-like creatures that you can often by fossils of) and phoronids (looks like a worm with tentacles). Now that I write this, I realize those two groups are not horribly well-known either.

If you look closely at a bryozoan colony, you see little boxes. Inside each box (or zooid) is the living animal which is basically a set of tentacles (called a lophophore) connected to a stomach, and a muscle for extending the tentacles. They feed by using little hairs (cilia) on the tentacles to filter water for food particles. Below you can see a close up of the zooids with lophophores out and feeding...

There are only ~5,000 species of bryozoans world-wide, and are found in many different habitats in the ocean , from docks to deep ocean. The lacy bryozoan is found on the pacific coast and generally tends to be subtidal. It has been hypothesized that the holes that make it look like lace, help direct the water flow over each zooid.

Animalpedia: Doridella and Membranipora

This a picture of a dorid nudibranch (Doridella steinbergae) and a bryozoan (Membranipora). Can you tell which is which?

The bryozoan is an encrusting animal that generally lives on kelps and also green algae. There is some debate as to if Membranipora is harmful to the kelp, but in general it is thought is can block the absorption of nutrients because it grows over the kelp.

Doridella is one of the few predators of Membranipora and is camouflaged to blend in with its prey. Normally, dorid nudibranchs have a circle of gills visible on their back, but Doridella’s gills are located behind the foot under a flap of skin. This helps them blend in better with the bryozoan. They feed on Membranipora by creating a suction seal, using their rasping tongue (called a radula) to cut through the outer membrane, then they suck out the insides.

Membranipora can create spines in response to predation by Doridella. Just put Membranipora in some seawater that has the nudibranch’s chemical cues in it, and it will make spines to protect itself from attack.

So did you find Doridella?

The two bumps on the top right are Doridella’s rhinophores, used for chemoreception. Only nudibranchs have rhinophores, so that’s the tip off.

Weekly Video: Bryozoan Lophophore

To get me in the mood for my upcoming talks, a video of one of my study organisms filtering water.



I look at the cilia beating, and long to be that industrious (or mindless!).