Introducing Ithaca

Of a pretty big disappointment to me is how much the terrestrial mollusk fauna in the Ithaca area is non-native. I guess, however, this is to be expected in a developed area-- even one that seems like it's known for it's natural areas (Ithaca is Gorges). Still, I'm spoiled by some good snailing back home in PA.

Here are some of the non-native species I've encounted:

Discus rotundatus

Photo by Aiwok: http://commons.wikimedia.org/wiki/File:Discus_rotundatus_2.JPG

Probably the snail I was most pleased to see out of the non-natives only because there are so many Discus Catskillensis where I live in PA. I found some of these near the Equestrian Center in Ithaca (can't remember what it's called, some sort of orchards).


Limax Maximus : Leopard Slug

Photo by Jonathan Feinberg http://commons.wikimedia.org/wiki/File:Leopard_Slug_Somerville_MA.jpeg

As far as the non-native slugs go, this is pretty cool the first time you see it. It's absolutely huge. Another species I've never encountered back in PA. I've found this slug in Sapsucker Woods and Monkey Run.


Trochulus hispidus : Hairy Snail

Photo by James K. Lindsey http://commons.wikimedia.org/wiki/File:Trichia.hispida.jpg

This could be a wrong identity on my part as Trochulus striolatus (Strawberry Snail) as juveniles of this species have periostracal structures as well. I've only found 2 alive and a ton of empties. I'll have to check inside the umbilicus of the many shells I found this week for hairs with a microscope when I go home to PA to see if I can confirm these as T. hispidus. Either way, I've seen Trochulus species at Sapsucker Woods and Salt Point.


Carychium minimum : Herald Thorn

Photo by snailmail http://commons.wikimedia.org/wiki/File:Carichium_minimum.jpg

I only found empties of this snail in stream drift from Buttermilk Falls. However, I read a paper about the snail being naturalized in wet areas around Beebe Lake on the Cornell campus. This is a tiny snail-- somewhere between 1.6mm and 2.2mm.

Other species about:

Cepaea nemoralis- around the Lab of Ornithology. Rose and yellow variants, as well as spiral lined. There may also be C. hortensis mixed in. That or it's some C. nemoralis juveniles reaching to about C. hortensis size and not yet developing the brown lip. I'll have to check harder next year. I tend to gloss over non-native species, not giving them the attention I do natives.
Oxychilus allarius- possibly. Cayuga Heights and near Lab of Ornithology
Arion species- Definitely subfuscus and possibly distinctus. Never pay much attention to ugly Arion slugs.
Deroceras reticulum- another ugly alien slug, everywhere.

Vitrina angelicae : Eastern Glass-Snail

I've said it once, and I'll say it again, the northeast region of Pennsylvania is fairly understudied (or at least under-reported) when it comes to nature, which is funny to think about, as it's located a short 2 hours from either Philadelphia or New York City. Multiply an understudied class of organisms by an understudied area and you've got a void of knowledge. This reason is why it's exciting (alright, let's talk in relativities) to be interested in snails and live, at least part-time, in Northeast PA. My sightings get to actually add to the knowledge base with new records.

Which brings me to Vitrina angelicae, the Eastern Glass-Snail. Also I've seen a common name of Transparent Vitrine Snail, but that name is pretty lame. According to Pilsbry, the genus name stems from the the latin word vitrum, which translates to glass and the species name is traced to the plant, Angelica archangelica, near which it was originally found.

According to the records, this snail is only known to reside in Western, mostly Northwestern, Pennsylvania. Also, according to what is known, the snail is an annual species--becoming active in October and dead by the spring. You can read about it at http://www.carnegiemnh.org/mollusks/palandsnails/vi_ange.html.

I also found information at http://www.livinglandscapes.bc.ca/cbasin/molluscs/vitrinidae.html which is an account of the related species Vitrina pellucida (the Western Glass-Snail). According to the website, Vitrina pellucida is carnivorous, and it's only difference with V. angelicae is anatomical. To test a little theory that then V. angelicae is also carnivorous I have it in a jar with what is likely prey, Cochlicopa lubrica-- which was found in proximity to the snail-- and Zonitoides arboreus.

I should also mention that I have found empty shells in two locations in Luzerne County. The first the island of trees and rocks in the turnaround at Nescopeck State Park where also present were plenty of Stenotrema hirsutum, and during the summer while taking my younger daughter through the Butterfly Garden at Frances Slocum State Park. I have also found the shells in the woods adjacent to the Butterfly Garden, though not very far into them.

From now on, instead of attaching an image to the snails known Pennsylvania counties I'll be just linking to my interactive known distribution map. To autoload Vitrinia angelicae go to http://kevinripka.com/pasnails/?snail=113.

Visualizing Pennsylvania Snails

Making a living on the web as I do, I find it inconvenient to have to look thru pdfs for data that is ripe for interactive visualization. So I took Pearce's Land Snails of Limestone Communites and Update of Land Snail Distributions in Pennsylvania and added in my own records to create an interactive map of the counties.

Don't know if it works in Internet Explorer, but it works in Chrome and Firefox. Seriously, it's 2011. There is no reason to use Internet Explorer. Let me get on my soapbox and say that Microsoft doesn't give a damn about user experience, web standards, or modern web practices. Use Chrome-- it's the best browser out there. Firefox is fine, too.

Here's the link:
http://kevinripka.com/pasnails/

Tricky Triodopsis

I've featured Triodopis species here before but I wanted to drop a quick not on identifying the congeners Tridopsis tridentata (Northern Three-tooth) and Triodopsis juxtidens (Atlantic Three-tooth). Later I'll update this article with some comparison photos but here is a mnemonic to keep in mind:

ATlantic is AT or Above,
Northern is southern.

What's being referred to here is which direction the distal edge of the palatal tooth points in relation to the upper palatal tooth-- the key to differentiation (morphologically).

You can read where I gleaned this identification information at the Carnegie site.

The real reason for this article is that I need a device for myself as I think I may be confusing the two. Often. The article says that 'ridge-and-valley' is mostly Atlantic but I've called most Northern. And, earlier today, I was at Frances Slocum and think I may have seen both in close proximity and couldn't remember for the life of me which was which. But maybe there weren't both. I have to be a little more intellectually vigilant sometimes. However, Slocum is just chock full o' Triodopsis so I don't pay that much attention. It's a 'hiding in plain sight' sort of thing.

I'll try to post pics soon to this article to illustrate the point.

UPDATE: No photos yet but I looked through shells I've collected heretofore and they are all indeed T. tridentata. I believe the shells I collected (and live individuals I saw) on the other side of Slocum are T. juxtidens (but I'm in Ithaca right now and don't have them on me) but that could mean both species are present in the park, albeit different sides of the lake. I don't see any appreciable difference in habitat so I find it fairly interesting.

Two Cool Finds at Hickory Run State Park

I finally got a chance to run to Hickory State Park in Carbon County, PA over the weekend. During the course of a few hours I stopped in 4 locations along the drive to do some snailing. The first few stops had me thinking it was another common, Northeast Pennsylvania snailing day. Most prevalent were Euchemotrema fraternum (Upland Pillsnail). At each stop I must have counted 10 to 20, mostly juvenile (juveniles identified by proximity to adults). Also common were what I called Philomycus flexuolaris (I don't think they were Megapallifera mutabilis, I remember a lighter foot fringe).

Pallifera species

At the first stop my first exciting find was a Pallifera species slug. My last post (wow, way back in June...) was about Pallifera ohioensis (Redfoot Mantleslug). This slug is a different Pallifera. Now, I have to assume it's probably a Pallifera dorsalis (Pale Mantleslug) but I'm not so sure. Pilsbry speaks of a mid-dorsal line of dots, but this slug lacks that. The rest of the descriptions seems pretty close. The slug in my possession is at times gray-blue and others reddish-tan. It has whitish speckles on the mantle which become little cinnamon flecks as above the foot fringe. It measures 10mm so I assume it's immature.

Interestingly I was able to find a few other photos of slugs online with close to the same markings (here and here and here). The biggest difference with mine is the darker markings on its head and tail.

UPDATE: Here it is the next day and I found a similarly marked Pallifera sp. at Frances Slocum State Park crawling on an empty Neohelix albolabris shell. Under the microscope, though, this one exhibits a faint mid-dorsal line of spots but lacks the darker markings (still dark over eye stalks). This slug is only 7mm.

Helicodiscus parallelus

The last stop of my day was where all the action was. Along a single fallen tree I found: more Euchemotrema fraternum, Discus catskillensis, Ventridens ligera, and possibly Zonitoides arboreus (pretty much the same snails I see all the time in my own county). But I also found what I thought was an empty Helicodiscus parallelus. I threw it in one of my little tupperwares I collect in and went home. Today, while inspecting it under the microscope I thought it looked as if there could be an animal inside. Adding a leaf of lettuce and a spritz of water I left it to sit. Later I came back to it and, sure enough, it was crawling around. 

This little snail measures 3.25mm. The coolest thing about this is that it's a little blind snail. If you look closely at the photo you'll see that there seems to be no eyes at the top of the tentacles where you normally see them on other snails. I've found empties before in stream drift in Ithaca, but this is my first encounter with a live animal.

Land Snails of Limestone Communities and Update of Land Snail Distributions in Pennsylvania (Pearce)

Funny enough, although the snail has widespread records, it was missing from Carbon County. I added it in green in the above map.

Pallifera ohioensis : Redfoot Mantleslug

Holy crap, how did I miss putting up a post in May? To be fair May is crunch time for birders and our beloved spring migration-- what with birds in their way-more-attractive-than-fall breeding plumages and all. On top of that the weather in Ithaca has finally changed over from frozen tundra to verdant tracts and, since I spend all my time on a computer at work, trekking outside takes way more precedence over blogging. In fact, I've got a whole backlog of images and thoughts to eventually catch up on.

This weekend, however, while at Ricketts Glenn State Park (still Luzerne Co., PA) I was more than pleased to find this little fellow-- what I believe to be Pallifera ohionensis (Sterki 1908), or Redfoot Mantleslug for you kids at home.

This individual was crawling about one foot up on a tree trunk that has provided me quite a bit of action. The week earlier I had found: 2 Anguispira alternata, 1 Xolotrema denotatum, and an at eye-level Euchemotrema fraternum that I noted the body was fully purple (I should mention I'm still not comfortable with the identification of Euchemotrema leai and should probably spend some time to suss the differences out, something about tighter coils, more delicate hairs, and wetter environments which this particular sighting is two steps to a creek). This day, besides the slug, was another Euchemotrema fraternum (this one with dark brownish up top and tan on bottom of body... better start paying more attention).

Looking in Hubricht it seems he lumped Pallifera ohioensis with Pallifera dorsalis (Pale Mantleslug). However, I do see P. ohioensis appearing places online so I guess it still enjoys full species status. In Pilsbry it makes mention of specimens from Douglas Lake, Cheybogan, MI that also have the rusty red and I think the subtext is that Sterki's identification is called into question. It goes on to mention, though, that Sterki had also recorded P. dorsalis and so thought the two species different-- perhaps Pilsbry sticking up for Sterki and more calling into question the Douglas Lake records with the rusty marks. Also, I have seen information floating around  out there that P. dorsalis is actually a complex and includes even more species. Did someone say 'ripe for genetic study?'

As far as a description goes this animal is pale with some gray flecking (it reminds me of every cubicle I've ever worked in, a color I call "greige" because it's not quite gray but not quite beige). It has a broken darker line with some darker spots more apparent anterior, but, as you can see from the photo, it has some splotchy gray running most of the body. Extended it was thin and this guy was probably somewhere in the 15 to 20mm range, making this an immature individual (or maybe a P. dorsalis, what do I know?). Full length is 30mm according to Pilsbry (who is giving the measurements according to Sterki). Of course, beside the mantle covering the body except head, the big thing that led me to its immediate identification (thanks to having previously read the Carnegie Museum Slug Key) were the rusty red lines going down it's foot fringe. It's face is gray-blue, and, as far as slugs go, it's just cute as a button.

Here are a couple more photos:

Range maps from Land Snails of Limestone Communities and Update of Land Snail Distributions in Pennsylvania (Pearce). SIghting record county (Luzerne) added in yellow.

Above you see the standard range map I use from Dr. Timothy Pearce. I continually find myself lucky to be (at least part time) in a state that actually has good, current, accessible information. You'll see that, if I'm correct on the identification, this is quite a good record. There are no records from the eastern 2/3 of the state. Here's P. dorsalis for comparison:

Note that P. dorsalis has a wider known range and even does have records for Luzerne County. If this were a breeding bird I'd question my sighting versus the range map, but, seeing as land snails are painfully understudied, it doesn't make me blink an eye. I won't be losing any sleep over calling it a Redfoot Mantleslug.

A thing I should have paid attention to is the type of tree that I'm finding so much action on. At least, however, I know exactly where the tree is as it is right on the trail, practically on Route 118 (maybe 1/16 of a mile), and part of a two tree set. I've said it once, and I'll say it again, Ricketts Glenn State Park is an understudied jewel. As a matter-of-fact, so is a lot of Northeastern Pennsylvania.

It's amazing how I find the introduced slugs (Arions, etc.) pretty disgusting but I absolutely love our native Philomycids. I think when the mantle isn't really separated out it makes for a nicer looking creature.

Next article definitely will be "Introducing Ithaca." An exposé on all the introduced species I'm finding here. I swear I've found way more introduced species than natives here!

Instead of Looking for Easter Eggs...

I did quite a bit of snailing over the Easter weekend. I am fortunate enough that my home in Dallas, PA is not far from plenty of really great habitat. But, more specifically, I am close to the great old growth forest of Ricketts Glen State Park. As such, I managed to steal a couple  hours both Saturday and Sunday to do a little snailing and birding at the glen.

The first day I really only worked a small patch where the road and the creek combine. While there was 'shit for birds' as I say when there isn't much bird action, there was certainly no lack of terrestrial mollusks.

One snail that I only found in one spot, but 6 individuals, was Euchemotrema fraternum. I interestingly read a couple days ago a reference by F. Wayne Grimm that this is actually a species complex as he wrote here about the species in Ontario.

Euchemotrema fraternum (Say, 1824) - A complex of at least three distinct forms, represented by pure populations and probable hybrids. As there are anatomical, distributional, and habitat differences, it is unwise to subsume them under "fraternum" and look the other way, hoping that a fascinating evolutionary problem will evaporate, leaving identifications simple. In the U.S. known from Minnesota, Iowa, and Missouri eastward across the Great Lakes Basin to Alabama, North Carolina, and New England (Hubricht, 1985). In Ontario, found frequently in mesic forest situations from Algoma and Temagami southward (Oughton, 1948: 9). Breeding experiments and comprehensive anatomical comparisons are to be undertaken when resources and time permit. 

They were all under bark that was laying on the ground within 15 feet of the creek. Alongside them were a couple Discus catskillensis and a immature Polygyrid.

I'm not sure why I didn't take apertural and umbilical views of any of the Discus catskillensis I found, but here is an apical view.

Another snail I found quite a bit of is Triodopsis tridentata. It's probably the polygyrid I find most in my county. 

One interesting individual looks as if he had to overcome some traumatic experience as you can see by the deformity of his body whorl getting close to the aperture and some breaklines:

Another snail I found a couple of is Anguispira alternata. The 'Flaming Tigersnails' that I've noted in the park are definitely not that flaming and instead rather dull compared to a some I've seen as far as the shell goes. But their bodies are very varied with purples and pinks.

I really didn't see many empty shells but had one that struck my fancy:

I haven't had a chance to work a key for it but I'm leaning towards Xolotrema denotatum. However, the ones I've seen in the park are thicker than this shell.  I'll have to revisit these photos at a later date but compare to below... pretty much the same except thickness. Plus this guy is light colored. Some I've seen are dark, hence the name Velvet Wedge.

The next day I found some different species, as well as had some new birds for my year. I had a singing Veery, which seems like it might be a week or so early but I'm terrible with dates and it could be spot on. Also the forest had my first of year Ruby-crowned Kinglets and Blue-headed Vireos.

Speaking of Xolotrema denotatum, I think here's one that seems to have lost his velvety periostracum that gives them the common name, Velvet Wedge:

I only found 2 introduced species, a single Arion subfuscus and a yellow Arion slug. I've seen a couple of these all yellow Arions in the park but am not sure which species it is. The one I found Sunday was immature and crawling on a log right next to a Philomycus flexuolaris.

Almost forgot, on Saturday I also found what I believe are of the Mesomphix genus, maybe Mesomphix perlaevis or inornatus, but I don't have a field microscope to check on the microsculpture, as it's my understanding you can differentiate the two species I mentioned by the presence or absence of minute papillae (see here):

Another snail of interest, this one from Sunday, was a 9mm Ventridens species that I haven't looked at a key to see if I can identify from my photos. But this little guy was just walking around on the leaf litter near one of the falls. Of course he tucked in the second I leaned down to photograph him. But I'd hide too if something way bigger than me was checking me out.

And the flowers were out:

And some mushrooms :

And one last cool thing I saw over the weekend, although this was at Moon Lake State Park which I just went birding and only lifted a couple rocks, finding this creature: a Smooth Green Snake (Liochlorophis vernalis), the first one I've ever seen. But I'm not a herp guy.

WAIT!! How could I forget about the snail I was most excited to find? At least, I'm reasonably sure of identification, I found 3 Haplotrema concavum in various places, but 2 were in close quarters with an Anguispira alternata and Triodopsis tridentata. For those that don't know, Haplotrema concavum is a snail-eating snail, a real killer. These were at Ricketts.

All very cool stuff! How the hell can anyone be bored when there's this much out there? And I'm only scratching the surface...