Friday, October 29, 2010

Identifying Zoidberg

Well, it's a learning process. It appears my first instinct was correct in the identification of my philomycid slug I affectionately refer to as Zoidberg-- it is a Philomycus togatus (Toga Mantleslug). I have observed the animal for a week or so now and realize that the foot sidewall always has a pinkish orange hue. In the field I guess the lighting made me think it was paler. Also the mucus color of orange is diagnostic as the only known philomycid with orange mucus is the Toga Mantleslug.

I can't find the reference where I read that P. togatus is the only Philomycid known to have orange mucus but I will update this post when I refind that quotation.

From H.L. Fairbanks' The Taxonomic Status of Philomycus Togatus (Pulmonata: Philomycidae): A Morphological and Electrophoretic Comparison with Philomycus Caolinianus (Malacologia, Vol. 27, No1, 1986):

"Among the species of Philomycus only P. rushi Clapp, 1920, a small (15-20mm) slug, has been described as having orange or red in the sides of the foot. Pilsbry (1948) synonymized P. rushi with Palifera ohioensis (Sterki). There are two large Palifera (P. varia and P. ragsdalei) with red or orange in the foot margins. However, Philomycus togatus has a dart sac and dart and therefore must remain in the genus Philomycus. This makes it the only know species in the genus recorded as having orange foot margins."

Interestingly I also now possess a P. carolinensis/ P. flexuolaris and the mucus is a milky white but it's very hard to see a difference in mantle pattern. Both individuals are heavily mottled but with the P. togatus I can make out lateral stripes on both sides. On the other I can just barely make out darker spots of dark brown/black on the back as two close lines leaving me still dumbfounded as to it's identification as either P. carolinensis or P. flexuolaris. If I went based on likelihood of know distribution I'd guess P. flexuolaris, especially since it was collected up here in the mountains in the northeastern portion of our state. Eventually I'll post photos and hopefully a definitive identification.

Range map from Land Snails of Limestone Communities and Update of Land Snail Distributions in Pennsylvania (Pearce) with my own county added to range (in orange). Formerly unknown to Luzerne County.

Wednesday, October 20, 2010

A Slug Named Zoidberg

Yesterday after I work I popped over the the mountain bike path side of Frances Slocum to see what I could find. Looking over at a log I found this nice, big Winding Mantleslug (Philomycus flexuolaris) just slugging on by. I grabbed him and he absolutely filled my hand with orange mucus. At first I thought maybe that meant it was a Toga Mantleslug (Philomycus togatus) as I didn't (and still don't) know the mucus color of P. flexuolaris. Ultimately, however, I believe this to be P. flexuolaris based on it's markings. Interestingly, though, I was thrown by the orange because the foot fringe looked pinkish orange when it was irritated and filling my hand with orange mucus, but after it rested the foot fringe went back to a paler color.

Today I brought him home a treat-- a bunch of fungus I collected. After all, as I learned yesterday, Philomycus (and probably the family, Philomycidae) translates to "friend of fungus." This is the name given by either Sterki or Rafinesque (or someone else, can't remember) when they named the genera/family because they eat fungus. I put him down on my photo table, presented him the fungus, and he went right to work.

Immediately upon inspecting him with my hasting triplet I named him Zoidberg. Now, I don't know if there is something inherently wrong with naming something you are going to dissect or preserve (basically murder), but I did it anyway. Look at that mouth, it has those vertical bars like the Futurama character. I pulled away the fungus and could see his full mouth. It looked like a suckerfish, but more sculpture to it.

I should also note that I was going to try to compare him to the first P. flexuolaris I had gotten from Moon Lake Park, but when I pulled out that jar I learned that it had escaped. Apparently I made the air hole way too big and it slid out. So now I must have a big 66mm mantleslug winding around my house. Oh well. Lesson learned: smaller holes.

Monday, October 18, 2010

Ventridens ligera : Globose Dome

Next on my list of identified Luzerne County land snails is Ventridens ligera, commonly known as the Globose Dome. These snails (or at least their shells) were under pretty much every log I lifted along the railroad tracks in West Wyoming near Airport Gravel and Sand.

Using Birch's 1962 key I came to the conclusion of Vitredens demissis (Perforate Dome). However, after reading more about the species on the Carnegie website I changed my mind. First, Vetridens demissis was completely left off his 2006 county distribution list. Second, in the account I learned that juveniles of Vitredens demissis have a basal lamina. After reading that I checked some of the juvenile shells I picked up and found no basal lamina leading me to rethink the identification. What I realized is that I still don't have a good grasp on what would constitute slightly depressed versus globose.

From there I believed it to be either Vitredens interdextus (Pyramid Dome) or Vitredens ligera. I was leaning towards Vitredens ligera, but not totally sure of myself after the misdiagnosis. So I shot an email off to Carnegie Mollusk Curator Tim Pearce to ask a few questions about Ventridens and identification in general.

He pointed out that Ventridens intertextus have a spiral striae (a fact I missed in the key) and that the juveniles have an angular periphery. So the identification was clinched in my mind as Ventridens ligera.


Range map from Land Snails of Limestone Communities and Update of Land Snail Distributions in Pennsylvania (Pearce) with my own county added to range (in orange). Formerly unknown to Luzerne County.

Identification notes:
Height: 10mm range
Width: 10mm range
Shell: Narrowly Perforate Heliciform
Lip: Thin, Unreflected
Apertural Teeth: None
Aperture: Ovate-lunate
Whorls: 6
Other: Pedal Groove

Location Found:
Along railroad tracks near Airport Gravel and Sand
West Woming, PA- Luzerne Co.
41.307306097168215, -75.85408061742783

Thursday, October 14, 2010

Known Luzerne County Land Snails

Carnegie Museum Curator Tim Pearce recently recompiled distribution maps of land snail species by county in Pennsylvania. My own county, Luzerne County, was among the least represented with less than 15 known species. So that's exciting in a way as now my information will be pretty valuable. Already I know a couple species that I've found aren't on the map. The pdf of distribution can be found at:

Here is the list of known species in Luzerne County:
Arion subfuscus
Discus catskillensis
Euchemotrema fraternum
Helicodiscus parallelus
Neohelix albolabris
Novisuccinea ovalis
Pallifera dorsalis
Ventridens intertextus
Zonitoides arboreus
Zonitoides nitidus

Tuesday, October 12, 2010

Philomycus flexuolaris: Winding Mantleslug

UPDATE: It seems slugs are not as easy as I assumed. This article could be totally wrong in identification. Unfortunately this fellow escaped his jar due to a too big slit in the aluminum foil cap I had on the jar and so I can't go back and, now a little more knowledgeable, make a definitive identification. So take anything written below with a grain of salt.

Slugs seem to be a little easier to get to species. There are 17 known species in Pennsylvania, most of them non-native. Also it helps that there is a great and current slug key of the known PA slugs on the Carnegie Museum site (

This slug is Philomycus flexuolaris, the Winding Mantleslug. It is a native of Pennsylvania and common in high elevation wooded areas. It is identified to family first by looking at the mantle. This one has the mantle covering the entirety of the back and over the head versus slugs that have a sectioned appearance. After that you can identify by the mottled dorsal line and mottled lateral lines on both sides.

I found this little guy (not that little, this one measures 66mm) under a log at Moon Lake Park while on a walk with my older daughter, Emma, and one of my dogs, Sasha.

Range map from Land Snails of Limestone Communities and Update of Land Snail Distributions in Pennsylvania (Pearce) with my own county added to range (in orange). Formerly unknown to Luzerne County.

Identification Notes:
Mantle: Full back and over head
Other: Mottled Dorsal Line and mottled Lateral lines on both sides

Location Found:
Moon Lake Park
Luzerne, Co.
41.25269, -76.055759
Macrohabitat: Mixed Deciduous (mostly oak)
Microhabitat: Under a decaying log used as the side of a path

Monday, October 11, 2010

Cepaea nemoralis: Brown-lipped Snail/Grove Snail

I'm not going to lie that I'm a little disappointed that the first snail I ever noticed/found happens to be a non-native species. Already as a birder I've grown an aversion to non-native species. Still, this is a cool looking snail. I found the original shell at a retention pond area in downtown Wilkes-Barre, PA along some railroad tracks. I was busy looking for sandpipers in the low water of the retention pond. So, once I decided I was into snails, I went back to look for a live specimen. Easily I found a bunch of these snails along the roadside as soon as I parked my car. To be fair, it was drizzling so they were moving about.

Cepaea nemoralis is a common snail of Europe. It goes by the common names Brown-lipped Snail and Grove Snail. It's a good sized snail- the shell I measured is about 21mm high and 20mm wide, give or take.

The most interesting thing while looking for an identification that this snail led me to was an article on thrush selection of banded snails at It seems the polymorphism of these snails (some seem to have more or less bands, yellowish to brownish base colors) helps them survive. Light snails fair better against light dry backgrounds, dark ones against dark backgrounds when it comes to being found and eaten by thrush and other creatures that find the tasty morsel snails by sight.

This is the actual first snail shell I ever collected.
Range map from Land Snails of Limestone Communities and Update of Land Snail Distributions in Pennsylvania (Pearce) with my own county added to range (in orange). Formerly unknown to Luzerne County.

Identification notes:
Height: about 21mm on mine
Width: about 20mm on mine (listed as 22-24mm in Burch)
Shell: Imperforate Heliciform
Lip: Reflected with a brown color
Apertural Teeth: None
Aperture: Ovate-lunate
Whorls: about 5
Other: Color Bands

Location Found:
Epsco Retention Ponds
Wilkes-Barre, PA- Luzerne Co.
41.25508923613776, -75.8547055721283

Amateur To Expert.... Someday

This is the inaugural post for LeafLitterCritters. In this blog I will start from absolutely zero knowledge about land snails (other than the fact I know a snail or slug to see one) and, hopefully, become versed in identification. I'll also occasionally post non-snail terrestrial creatures and whatever of interest I find while out rooting through the leaf litter.

The exposition as to why I've become fixated on land snails comes in two parts. First, while out birding I picked up a rather interesting snail shell and gave it to my daughter, Emma. I didn't identify it or anything, in fact didn't think much about it-- other than I thought it was interesting.

Fast forward to about 6 months later when I was watching PBS and a segment on the episode of 'Nature' centered around the Cuban Painted Snail.  I don't know if you've seen the show 'Nature,' but the cinematography is stunning. And seeing snails the full size of my big screen television-- their scultpure, the eyes at top of their tentacles/stalks-- I was hooked.

It's been about two weeks since I've become fixated on land snails and I already realize one thing-- snail identification is tough. It's not that I don't possess the wherewithal, after all I pride myself on being rather good at sandpiper identification (a tough group of birds), it's that it is hard to find information on snail identification. I can jump on any website and buy a few books on bird identification. Snails, not so much. It took me a week to find a book by John Burch from the 60s entitled: How to Know the Eastern Land Snails. Of course, it's out of date in some ways,  particularly in current taxonomy, but it's a start.

One website I found that is going to be my go-to site is the Carnegie Museum of Natural History's Pennsylvania Land Snail page. I'm lucky to find a page dedicated to the snails in my own state, as there don't seem to be many states that have the same. It's at

But, I digress, and I'm ready to take on the challenge of becoming knowledgeable about land snails.