Monday, June 6, 2011

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!