Pardosa cf. ramulosa - Pardosa ramulosa

Specimen -

KRS-2010-37

… Ken Schneider, 22 June, 2013 - 1:05pm

Moved

Moved from Thinlegged Wolf Spiders.

Comment from Dr. Vogel:
"This picture isn't as nice as the P. californica but the beast is probably identified correctly... The guide doesn't name the identifier of P. ramulosa, but it is ok to call it that. I am not sure P. ramulosa isn't the same as P. sternalis, but there is a gap in the range of the beastie, and so far we call the western one P.ramulosa".

Dr. Vogel didn't mention tuoba in her comment and I'm reluctant to bug her more with questions about these images... I'm moving to the species level for now, with the understanding that this is a difficult species group to ID and we don't have absolute certainty here...

… Ken Schneider, 22 February, 2010 - 9:07pm

Sounds good to me! (What does she mean by "the guide doesn't name the identifier of P. ramulosa"? I can't figure out what the context is -- BugGuide? And what might the "identifier" be -- the person who made the identification?)

… Kevin Pfeiffer, 23 February, 2010 - 12:53am

Yes -

I'm not sure, but I believe she was trying to figure out the Bug Guide structure. Perhaps she meant the author of the species?

… Ken Schneider, 23 February, 2010 - 11:08am

And/or ask RC?

Rod C. might be able to help -- he's collected specimens of P. ramulosa (they're in his collecting journal).

-K

… Kevin Pfeiffer, 14 February, 2010 - 4:06pm

Greenstone

Perhaps I've answered my own question. This is from a paper (1980) by Greenstone:

"Salt- and freshwater marshes are, without exception, inhabited exclusively by Pardosa ramulosa, which is also found on the margins of the small pipe-fed and vernal pools in Point Pinole and Tilden Regional parks but not at the spring in Coyote Hills Regional Park. Pardosa tuoba is never found outside the prairie and scrub habitats, although it is conspicuously absent from Neil's Island, which contains large areas of typical coastal prairie."

"The salient difference between the habitat distributions of these two species is the presence of open standing water in all Pardosa ramulosa habitats and its absence from most P. tuoba habitats.... P. ramulosa's association with open standing water reflects specialization in foraging mode, the spiders hunting preferentially at the surface film of small bodies of standing water."

-K

… Kevin Pfeiffer, 14 February, 2010 - 2:43pm

Thanks, Kevin!

for that reference - I'll have to take a look at the whole article. I think that Vogel's paper says that the epigyna can separate the two also, and I thought this fit ramulosa better - see p. 102 of the 2004 Vogel revision. I've emailed Dr. Vogel to see if she'd be willing to look at these images to confirm...

… Ken Schneider, 14 February, 2010 - 3:25pm

For P. tuoba she writes that "females can be identiﬁed by the basal portion of the septum which is wide enough to nearly cover the cavities".

And in the key for P. tuoba: "Median septum rectangular and nearly covering cavities".

But isn't that what we see in the image -- a broad median septum that is wide enough to nearly cover the cavities? Well, as you can tell, I'm not sure what it is I see. You've got the advantage of being there.

Signed,

Confused in Berlin :-)

… Kevin Pfeiffer, 14 February, 2010 - 4:00pm

Well -

I'm not sure I'm correct, but I see (under the scope, even if the pic isn't great) that the posterior end of the septum (the basal portion, I believe) is about as narrow as the rest of the septum - it doesn't stand out well in the pic, but if you look closely, you can see two round cavities flanking the base of the septum...

… Ken Schneider, 14 February, 2010 - 11:28pm

I superimposed Vogel's drawings of the two species on your image. Not sure if that solves the dilemma, but the result is interesting to look at: http://forum.canadianarachnology.org/viewtopic.php?p=3156

BTW, I'm perfectly happy with "Pardosa cf. ramulosa". It will be interesting to see if anyone with more experience can give us a definitive answer.

-K

… Kevin Pfeiffer, 15 February, 2010 - 2:19am

Hi Ken, I've only looked v

Hi Ken,

I've only looked very briefly at Vogel, 2004, so far. Have you already excluded P. tuoba? (California, under 500 m)

-K

… Kevin Pfeiffer, 14 February, 2010 - 1:50pm