Wednesday, January 26, 2011

It's a Boy! (and a girl)

Okay, so snails (well most land snails) are hermaphroditic— I can't really pick out a color for the walls—but what you're seeing above are freshly hatched snails. I found a large clutch of eggs when I was cleaning out my terrarium to combat mites and so removed them to a couple separate petri dishes. It seems the petri dish that stayed dryer is first to have hatches, with one individual hatching a day ago and the rest following suit a day later.

There are only a handful of possibilities for what these little snails will become based on what is in the terrarium. It holds the following species: Stenotrema hirsutum(1), Ventridens ligera (3, maybe 4 but one really doesn't "measure up"), Xolotrema denotata(2 but I doubt have reached sexual maturity as I found them a few months ago still without identifiable characteristics), Novisuccinea ovalis(1), Anguispira alternata(1), Triodopsis tridenata (1, but very new to the tank, can't remember if came before eggs), and, my top contender for what these babies are, Neohelix dentifera(1).

UPDATE: As you can see by the laconic comment below, these snails are likely the Anguispira alternata. I was so focused on how big I thought the eggs were that it had to be the largest snail in my tank but you can see how these little guys look like they grow into ribbed adults and have color blotches a la Anguispira alternata. Learning experience!! I would never make such a bad call birding, fixating on one criterion. Proof positive that inexperience is definitely a detriment. The only solution: work my ass off to get experience.

As time goes on, I'll find the answer. An interesting characteristic is that the snails have two transverse bands of dark color towards the end of their body whorl. And, for scale, I should mention that they average about 2.35mm in width.

Currently I also have another polygyrid waiting to grow into identification that has periostracal structures, so I've got a lot to look forward to. Yes, I'm a total nerd. But I'm a sexy nerd.

Tuesday, January 11, 2011

More Photography of Stenotrema hirsutum

I needed to take some time off of web and app development tonight so I decided I'd do a little photo shoot. I chose to photograph a Stenotrema hirsutum I found at Nescopeck. The problem with  Stenotrema, as I see it, is that you can't fully tell if the shell is empty. I left it with a couple shells I had in a little petri dish and when I went back into my office I found it hanging from the top of the lid. Empty shells don't generally do that.

Anyway, as an aside, I'll mention here that I launched my new website It's for app development and digital media publishing of nature subjects. 

Above is my favorite photo from the ones I took. An interesting thing to note is that this S. hirsutum, along with a second, which I found at Nescopeck are a darker brown than the one I found at Frances Slocum (other side of the county). Also the body color is more gray on the other snail. Maybe these are two different species and one isn't S. hirsutum at all, let's face it, I'm still a neophyte. But they both are the same size and whorls and pretty much seem the same. I'll put more effort into comparing both live individuals at a later date. For reference there is a photo of the other S. hirsutum here.

I also drew the snail's ventral view. I really should make a comparative drawing of the Frances Slocum individual and look for any differences, but, honestly, I'm just feeling tired and lazy from working so much and not sleeping well this week. I'll do it some other day and post a comparison. But, as I look at my drawing while I type, I pretty much remember the same characteristics.

Monday, January 3, 2011

A Big Mystery

Through some good fortune the large storm that dumped snow over much of the east coast stayed to our east and left us with relatively snow free ground. So during the holiday break I went to Nescopeck State Park to do a little combo snailing/birding. Birding was absolutely dead. I had hoped for winter finches like Redpolls and Siskin, but arrived to find the feeders empty, as was much of the park. With bird life at nil, I turned my attention fully to snails.

Overall I was very pleased with my snailing. I found my very first Vitrina angelicae (Eastern Glass-Snail) shell sitting in a pile of leaves on top of a flat rock. I also found some Triodopsis tridentata and a couple Stenotrema  hirsutum. Another interesting find was a 6 whorled heliciform shell that doesn't match up with anything in my database (the one I built for my iphone app), so I'll have to look into more.

Most importantly I was pretty excited to find what is my largest land snail yet. The above picture is of that snail. The shell was in/under a log that looked like it  had a hole for some rodent. My best guess is that this fellow became dinner. But luckily, there seems to be enough information left in the shell to make an identification.

First, obviously, we can say it's heliciform (72 matches). The width measure 28.4mm (11 matches) and it is imperforate (6 matches) with a reflected lip(5 matches). No teeth are present(this has 3 options- no teeth, teeth and teeth sometimes present- it always pulls the sometimes matches plus the yes or no depending on input). Plugging that into my app, I came up with 3 suspects: Mesodon zaletus, Neohelix albolabris, and Webbhelix multilineata.

From there it's time to take to Pilsbry but not before first taking a look in the microscope for any microsculpture I could glean (unfortuneately I haven't 100% finished to database for things like striae, puncta, etc.) . But there is what seems to be some crucial evidence-- indented radial striae.

Regarding microsculpture and the aforementioned snails according to Pilsbry:

Mesodon zaletus:
Later whorls with sculpture of fine oblique striae and microscopic spiral lines, which are typically rather weak or subobsolete, but sometimes distinct.
Neohelix albolabris:
Later whorls with sculpture of fine oblique striae and minute, crowded, incised spiral lines.
Webbhelix multilineata:
... the rest with fine sculpture of oblique striae, rather weak spiral engraved lines in their intervals.

Here is the microsculpture.

There seems to be no mention of the spiral lines being indented with Mesodon zaletus. Webbhelix multilineata usually has color bands (although Pilsbry mentions a mutation known as Webbhelix multilineata mut. alba that is bandless and can occur with the banded shell populations). However, I believe the description of 'crowded, incised spiral lines' sees to hit the mark.

So, I believe this mystery solved. It is the snail Neohelix albolabris (common name, Whitelip).