Hammock Spider - Pityohyphantes subarcticus

P. subarcticus

Okay, based on the shape of the patellar apophysis on the pedipalp as well as other characteristics described by Don Buckle in unpubl. notes, both John S. and I are convinced that this is P. subarcticus, which prefers conifer woods, but can also be found together with P. costatus in mixed forest environments.

For the sake of completeness, I also just sent a note to Andrei Tanasevitch. His Black Rock P. subarcticus specimen (which superficially looks more like P. costatus) can be seen here:
http://research.amnh.org/iz/blackrock2/pictures/spider_images/galleries/linyphiidae/pityohyphantes_subarcticus.htm

I will let you know what I find out.

… Kevin Pfeiffer, 20 October, 2010 - 7:50am

Moved

Moved from Hammock Spider.

(I know I'm going to get yelled at for this...)

After looking at Tom's female specimen (see thumbnail below), I'm of the opinion that these Massachnusetts specimens may well be P. subarcticus. True the state is not exactly "just south of the Arctic circle", but no less than A. Tanasevitch, AMNH, has collected specimens of the species from Cornwall, NY (Black Rock Forest, even lower in latitude).

So, for now, I'm going with P. subarcticus.

I'll add that what convinced me here is the length and size of the tibial apophysis. In Paquin & Dupérré's drawings the palp is more or less identical (allowing for small variances in the position, etc.). But she shows the tibial apophysis of P. costatus as being significantly more substantial and longer -- extending well beyond the tibia/palp junction. P. subarcticus, on the other hand, extends just barely up to this junction. A subtle difference, granted, and I do not yet know if it is a significant characteristic.

My thought is to now write to Andrei T. and see if he can offer any further advice.

.. female MA specimen

… Kevin Pfeiffer, 6 October, 2010 - 7:21am

> My thought is to now write to Andrei T. and see if he can offer any further advice.

I, too, would be interested in what he has to say.

… John Sloan, 6 October, 2010 - 2:41pm

Moved

Moved from Pityohyphantes.

… Lynette Elliott, 27 December, 2009 - 10:20am

Moved

Moved from Sheetweb Spiders.

… tom murray, 29 November, 2009 - 4:18pm

Pityohyphantes, I would guess

Pityohyphantes, I would guess...

-Kevin

… Kevin Pfeiffer, 29 November, 2009 - 4:15pm

Agree

Agree. Too bad it's immature. A species ID would have been nice. I wouldn't be surprised if it was a P. costatus. The subadults look like the adults, only a tad smaller.

… John Sloan, 29 November, 2009 - 4:51pm

Mature pictures added

I kept it, and now it's mature, and I added a couple of pictures.

… tom murray, 24 December, 2009 - 8:43pm

Yes, the palp appears to conf

Yes, the palp appears to confirm this as Pityohyphantes costatus.

-Kevin

Specimen: kmp-5769

… Kevin Pfeiffer, 27 December, 2009 - 8:25am

P. costatus is what I was als

P. costatus is what I was also thinking, even though this specimen appears a bit darker than some I've looked at.

-K

… Kevin Pfeiffer, 29 November, 2009 - 4:58pm

Color varies

I probably looked at close to 50 or more P. costatus this past summer, in various habitats. The color seems to range from light to dark. Some of them even have a yellow hue to the abdomen. Most in my area are a tad lighter than this one, but I've seen ones as dark.

This is another one of those variable species.

… John Sloan, 29 November, 2009 - 6:45pm

Subadult

I'll try to get it to maturity, and see if we can get a possitive species ID.

… tom murray, 29 November, 2009 - 5:02pm