Thursday, August 22, 2013

An unusual "moss"

It’s not so much that I feel compelled to point out that there’s a lot to see out in our vernal pools at this time of year; it just turns out that I’m finding some neat stuff lately. You should go out and look, too!

Mossy stick, or something else?
Here’s something you don’t see every day. About a month ago I was out with the Walden Pond State Reservation’s Junior Rangers leading a ponding activity in a vernal pool on the state reservation. I noticed a fuzzy section of a buttonbush shrub stem just below the waterline, which at first appeared to be covered in moss. I’m not sure what clicked to suggest it wasn't moss, but something did. I was pretty sure that it was a bryozoan, or moss animal, of some sort (one of the benefits of taking an aquatic macro invertebrates class with a professor who spent much of his career focused on esoteric animals is that you become aware of some unusual things). I went back a couple of days ago to collect some.

Doesn't look like much from here!
Back in the lab, I put the stick into a neat contraption for observing wee beasties, and was thrilled to see the fuzz turning into what I was expecting – a moss animal. It keys out to Plumatella recluse, for which there are only 6 other records in Massachusetts! Moss animals are colonial organisms in the Phylum Ectoprocta. The colony is made up of macroscopic zooids which can create a fairly large colony encrusting a substrate. Much like a coral or hydra, moss animals have tentacles that they extend, and wait for food items to become ensnared. In this species, the tentacles on the lophophore are arranged in a horseshoe shape.

Close-up of P. recluse zooids, lophophores, and sessoblasts.
Moss animals reproduce both asexually and sexually, the latter resulting in a planktonic larva that can establish a new colony. The third photograph shows small, brown “dots” throughout the mass. These are the result of one form of asexual reproduction they employ, and importantly, the way this species gets through dry periods in vernal pools. As environmental stresses increase (ie, the pool starts to dry out), individual zooids begin to produce statoblasts, which are little, round capsules containing the germ of the next colony. These either float (floatoblasts) and get carried away to other places, or stay attached to the parent substrate (sessoblasts) and await the cue to start the process all over again.

Sometimes sticks get fuzzy with moss and algae. Sometimes, though, they get fuzzy with really unusual animals masquerading as moss and algae. Keep an eye out! ~ MR Burne

Thursday, August 15, 2013

Coolest. Frog. Ever.

Sitting on damp dirt and leaves, he's dark.
This little fellow showed up on the door of my office building a couple of days ago. He’s been visiting for a short bit to ham it up for the cameras. This is, of course, the Gray Treefrog, Hyla versicolor, the coolest frog ever. Well, at least the coolest frog native to the northeastern US. In my humble opinion, anyway. Coolness is, after all, subjective.

After 20 minutes sitting on white paper, not so much.
Gray treefrogs are a sort of meaty frog, getting close to two inches long when they’re full grown. They have suction cup toes, so they can spiderman their way up trees, the side of a building, glass, your hand, whatever. A few years back, a gray treefrog was found hiding under a roof shingle next to a dormer on the third floor of our office building. Not “natural” habitat, but apparently it can make for happy frogs.

Gray treefrogs are masters of disguise, changing color to more or less match their background. Their color range includes dark chocolate to nearly ash-white, and a beautiful emerald green. The two photos here were taken about 20 minutes apart, so the transition is relatively quick.

Breeding for this species is typically in late April or early May, though that’s variable and can happen later in the spring/early summer as they develop very quickly. Here’s a link to a clip of their beautiful, bird-like call: At this time of year, tadpoles have metamorphosed or are very close, and young-of-the-year are decked out in a brilliant emerald color, and are about the size of a full-grown spring peeper, or three-quarters of an inch. I've most often found them hanging out on the leaves of buttonbush and other shrubs in the vernal pools they (presumably) grew up in. I hear adults calling from the trees on the oak and pine hill up behind my office every now and again, which will continue through the summer. Just reminding us that, even though we can't see them right now, the coolest frog ever is close by, I guess.

It’s easy to forget that there’s a lot of interesting life happening in vernal pools in late summer and early fall, but that’s when a lot of animals that started off in the Big Night rush of March and April “graduate” and start kick off the next generation. ~MR Burne