Posts Tagged 'snails'

Mollusks

Some of the highlights of our gastropod crawl in Central Park on Monday and Tuesday: Helisoma trivolvisHelisoma trivolvis, called the Ramshorn or Three-whorled Rams Horn, a fresh-water species fished out of the Meer. This specimen, the only one found, was 1/2″ or 14mm long.Oxychilus cellariusThe ground was quite dry, so we knew that land snails would be a challenge to find. They like moisture and the night; the sun is their enemy. But we did see numerous Oxychilus cellarius, the Common Cellar Snail, under damp wood. This is a species that favors human habitation, as its names suggest. Originally from Europe, these are quite small: the largest was 8mm, most were around 5mm. Note the translucent shell when the animal, a glistening blue-gray, is fully extended outside. Here’s another look at these hard-to-photograph critters:Oxychilus cellarius

Also clinging to the dampness of old pieces of wood were the slugs, hiding out from the day:Limax maximusLimax maximus, the Leopard slug, another European import. I’ve seen them up to four inches long, which goes towards another of their common names, the Giant Garden Slug. One fearless student had one wrapped around her finger. Ok, it was a latex-gloved finger, but still, she and everybody else thought it was pretty damn fascinating, tentacle eyes advancing, breathing hole visible.ArionAnother slug, Arion subfuscus, which are reputed to taste absolutely terrible. About an inch long here, but all the slugs, and snails, are remarkably stretchy creatures. Slugs can contact to a sixth of their full length; if I could do this I’d be down to about a foot high in my boots.

Gastropods, you will no doubt remember, are a class within the phylum Mollusca, which is named after the Latin word for the “soft things.” utamaroWhat? Well, this stylized octopus — another mollusk — meets Utamaro-inspired ukiyo/manga paste-up was not found in Central Park, but at the end of the day on Smith Street.

Spring Cleaning Snails

snailsThree different specimens of our old friend Cepaea nemoralis.snail2snail3snail4The snail’s “foot,” which gave rise to the name for this whole class of Molluscs, Gastropoda, which means simply stomach-foot (and is anatomically incorrect; the stomach is in the portion of the animal that is inside the shell).snail5Just a size comparison with some other snails found during this clean up. The mm ruler looks bent because the macro lens distorts at the edges, either that or the omphalos of the shells draws gravity in like a black hole.snail6Unknown species on the left;Discus rotundatus on the right.

Snug as a snail in a snail

I like the idea of one gastropod hanging out in the shell of another. You’ve seen this before: the Queen Conch shells I lugged home — not from the Caribbean, but from Dead Horse Bay’s eroding landfill — provide an excellent shelter for terrestrial snails. Cepaea nemoralis, the Brown-lipped snail. A new squatter, as an individual, but a familiar species.

Tiny snail

Responding to my last post, snail maven Aydin Örstan thought the third of the terrestrial snails harboring on the marine snail shell in my backyard was Vallonia costata. If so — and it looks like it to this mollusk amateur — that would make for five different species of snails found in my concrete slab of a Brooklyn backyard so far.

This snail is tiny, 2mm across, and posed here on FDR’s eye on a dime. My antique snail book, Shells from Cape Cod to Cape May with Special Reference to the New York City Area (Dover, 1971, reprinting a 1961 original) by Jacobson and Emerson, notes that this Eurasian species wasn’t reported in the NYC area until “recently” when some were found in the Bronx, in a colony subsequently destroyed by construction. Jacobson and Emerson inform me that the ridge-like axial ribs on this shell are also known as costae.The hollow at the center of the whorl is called an umbilicus.

Queen Mother Conch

Some time ago, I found a couple of queen conch shells, Strombus gigas, at Dead Horse Bay. Needless to say, this is not this tropical species typical habitat. But the landfill at Dead Horse Bay turns up the strangest things sometimes. Perhaps these were somebody’s souvenirs once. Anyway, a ruthless recycler, I put the shells in the Back 40 for ornamental purposes. The other day, I turned over the one that sits on the concrete. Two — perhaps three — species of snails were attached.Cepaea nemoralis.Discus rotundatus.Tiny: no more than two millimeters across. Wondering if these — there was at least one more — are young versions of the above Discus? UPDATE: wonders never cease; this is actually probably V. costata, as discussed in the next post.
Sculptural conch sounding the arrival of Neptune at the Bailey Fountain at Grand Army Plaza.

Three for Thanksgiving

A trio of things found in a southeastern New Hampshire garden this summer by our Thanksgiving dinner host.

Burying beetle, Nicrophorus orbicollis. Gray lancetooth snail, Haplotrema concavum (I think). Six-spotted tiger beetle, Cicindela sexguttata.

Let’s take a closer look at the latter:The elytra are parted to reveal the underwings.

Back 40 Snail

A snail in the Back 40, hunkered down on the fence. Invasive Cepaea nemoralis, no stranger here. Showed up on Friday. Some mucous glue holds this onto the vertical surface, the animal withdrawn deep into the whorls of the shell.


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