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Pterostichus acutipes - Pterostichus

Pterostichus acutipes - Pterostichus
The Great Smoky Mountains, Sevier County, Tennessee, USA
March 23, 2016
Size: ~18mm
Feel free to frass this if it is not up to par.

I figured I would share some interesting information on what I believe to be Pterostichus acutipes.

I found this guy underneath a good size rock deeply embedded alongside a Dicaelus teter specimen off of Cherokee Orchard rd. Both were heavily infested with mites.

I've found it quite convenient to distinguish P. acutipes from P. rostratus (which I've observed in collections) through both size, and the shape of the pronotum. P. acutipes is often nearly 18mm and has a more robust pronotum, being wider apically and more rounded than that of P. rostratus. Another personal, potentially flawed, observation I've made is that fully formed specimens of P. acutipes more often have a reddish hue (not well photographed here) than P. rostratus which are almost always jet-black. Still, by far, the best indicator is the shape of the hind trochanters which are pointy here. Not well photographed due to the flash, but you can just make out the tip as a black pixel.

A very cool specimen indeed. It was hard to let go of this one, but in the end I released it back to its daytime slumber. Happy hunting!

Images of this individual: tag all
Pterostichus acutipes - Pterostichus Pterostichus acutipes - Pterostichus

Cool! You're finding nice S. Appalachian stuff already.
My experience with the color is the opposite- the acutipes in my collection are totally black, and the one rostratus I've collected is ferruginous. Of course big collections have all range of colors from black to nearly tan.

Thanks for that snippet highlighting the importance of a large sample size when making such observations haha. I'm excited to look around this season and try to get some permits for some sites so I can actually build my personal collection. I hadn't realized how difficult that process could potentially be....

Where did you find your P. acutipes if you don't mind me asking. Also, is it P. a. kentuckensis?

I've been making some strides with Steniridia and will probably shoot you an email in the near future discussing the group. It presents an interesting case of speciation and of localized forms.

The acutipes I have were collected from a pitfall survey in a cave in Lee County VA. So not collected by me, obviously. The acutipes in VA are supposedly all "kentuckensis", but I haven't spent much time trying to confirm which subspecies they are.. the differences are pretty slight, if I remember correctly. The coolest Cylindrocharis to look for is hypogeus! It's tiny and lives in the soil, has reduced eyes.

There is plenty of national forest land down there, and it's all open for collecting, no permit required.
Somewhere on this site is a discussion about a public land that's adjacent to GSMNP and allows collecting, I can't remember what place it was..

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