Do you love the challenge of the close-up mystery photos, and are you always looking forward to the next one? Well, there's no need to wait! ;) I haven't been able to get out in the field recently, so I went back into the archives for this one. It's also going to be tricky, but see what you think. I'll post the answer soon.
Apologies for the delay. A couple of nights ago, I posted a mystery photo and asked if you recognized the type of animal it was:
This is a tough one!
But isn't it intriguing?
I can give you a small hint, and tell you that the picture shows the animal viewed from above.
And here's another clue: This is the larval stage of a marine invertebrate. So it's quite small (microscopic).
What makes it look so "spiky" are very long cilia used for swimming.
As an adult, it's colonial — and the feeding members of the colony extend beautiful, bell-like lophophores to capture food particles from the water (see pictures at the end of this post).
Here's a view of the same animal from the side:
Note the triangular shape. You can see that the lower edge is fringed by cilia, and that there's an apical tuft at the top.
This is a cyphonautes larva — the swimming stage of some species of bryozoans (the most common example in this area would be Membranipora).
In the image above, perhaps you noticed the long, narrow "bar" in the middle of the cyphonautes larva (it looks like a straw)? It's one of the ciliated ridges that the larva uses to feed.
The diagram below illustrates the basic feeding process. There are different types of cilia on the ridges. They draw water into an incurrent chamber, sieve particles from that water, move the particles to the mouth, then the water exits through the excurrent chamber:
Diagram modified from Strathmann and McEdward. 1986. Cyphonautes' ciliary sieve breaks a biological rule of inference. Biol. Bull. 171: 694-700.
Below is a short video clip of a cyphonautes larva swimming — viewed from the side and from above. After watching the video, be sure to scroll down to see photos of the adults, too.
larva will swim in the open ocean for several weeks before finding a
place to settle down. You'll recognize adult bryozoan colonies as white, lacy
crusts on kelps or other seaweeds. Here's what they look like under a microscope:
The adult bryozoan colony and the cyphonautes larva look so different that it was a long time before the connection was made between the two stages. It's easy to see why!
Lots of chores today, so not much time tonight. For now I'll leave you with a fun mystery photo. Do you have any guesses about what type of animal this is? I'll reveal the answer soon, but you have a little time to study and wonder. ;)
Once again, Eric's sharp eyes spotted a very special animal in the intertidal zone on Bodega Head.
Meet Lissothuria nutriens, also known as the Scarlet Sea Cucumber. (Remember that sea cucumbers are in the echinoderm Class Holothuroidea). Don't worry if you haven't seen this species before — they're small — usually less than ~2 cm (~0.75 inches) long.
And this species is more common from Monterey Bay south. It's probably rare in northern California. There's only one record in the California Academy of Sciences collection for Marin and Sonoma counties (from Duxbury Reef).
Here's a close-up of the branched tentacles:
And one of my favorite views — the wonderful, elephantine tube feet on the ventral (under) surface. Note the shiny ossicles.
Although Lissothuria can move around, they are mostly sedentary. This individual was partially camouflaged by bits of shell, algae, and other debris held by its tube feet.
Interestingly, this sea cucumber is a brooder — it releases eggs and broods them in pits on its dorsal surface, so the potential for long distance dispersal of its young is low.
This is our second time finding Lissothuria on Bodega Head. It's intriguing to think about how they got here and to wonder about whether they'll become more common in the future (if water temperatures become warmer).
I've become quite enamored with pipits since moving to the West Coast. This one was taking advantage of the high tide in the salt marsh in Bodega Harbor today, searching for insects among the vegetation along the water's edge.
I was having fun just observing the pipit in its habitat, watching it feeding, wondering about what it was finding...
...when I noticed something I hadn't seen before:
Sometimes the feathers above the pipit's eyes flared into little tufts!
I'm not sure what was going on, as I don't recall noticing this in pipits before, or seeing it mentioned when reading about them. But it was definitely there on several occasions. Have I just been missing it? Have you seen this before? Do you know what it's about? I'd be interested in your observations and thoughts.
If you walked by a tidepool and saw this, would you recognize it?
The brown substance in the water is distinctive once you've seen it a few times. Here's another view, a few seconds later (below). Note how it changes shape, and that it doesn't dissolve or disappear right away:
And the answer is? Well, here's the animal responsible for it:
The brown substance in the water is octopus ink. This octopus released a cloud of ink while jetting across a shallow tidepool. Afterwards, the octopus settled on the bottom briefly and then crawled under a rock.
Octopus ink is a combination of pigment, e.g., melanin (released by the ink sac) and mucous (released by the funnel organ). It's quite effective as a distraction. The ink morphs into a variety of shapes, and stays visible for several minutes — giving the octopus plenty of time to escape while a potential predator is confused by the ink.
You might have seen some cephalopod ink that is black. Ink color varies depending on the species. Whenever we've seen Octopus rubescens ink, it's been orange-brown in color.