Microlinyphia mandibulata (Linyphiidae: Linyphiinae))

[jsloan]

Here's an odd male spider that turned up in one of my pitfall traps a few days ago. It has a very long, threadlike embolus in the palp (looks like a coiled up guitar string); long chelicerae angled slightly to the rear; a rounded, elongated carapace; and a dent in its abdomen. BL = 4.5mm

It's one of the sheetweb spiders. I must have caught it when it was out looking for a mate.

 

[jsloan]

Here's one of the few decent live shots I got of it (it hardly ever stopped moving).

 

[Bastian Drolshagen]

hi jsloan,
a nice find
Do you like IDing Linyphiidae? I gotta admit, that I hate it - more than any other family ^^
Afaik there´s going to be a new interactive ID key for them on the net soon (getting tested atm), but this will probably only cover European species.

 

[jsloan]

hi jsloan,
a nice find
Do you like IDing Linyphiidae? I gotta admit, that I hate it - more than any other family ^^

I haven't really ID'd all that many linyphiids, actually. Mostly Linyphiinae more than Erigoninae. It's certainly a tough family! I was able to ID this one because it's so odd. Those palps really stand out!

I'm finding a lot of eigonines this year in the BL=1 to 2mm range, really small spiders, all adults, and just about all of them different from one another. I'm saving most of them for a few years down the line and maybe one long winter I'll work on keying them out. What I need to get first is a better microscope (or some higher mag. eyepieces). Mine only goes up to 40x, which isn't enough to see much detail on these little guys.

Afaik there´s going to be a new interactive ID key for them on the net soon (getting tested atm), but this will probably only cover European species.

I'd be interested in seeing that when it comes out.

I do think Linyphiidae is an interesting family, though, considering the variety and number of species in this area. I always like to put one under a microscope, because I never know what it's going to look like until I do. There's usually some kind of surprise, especially with the males.

Another thing I find interesting is that so many of these spiders are active during the winter, under the snow. I may set some pitfall traps next winter (with preservative in them) and see what turns up.

 

[Bastian Drolshagen]

hi,
same here, have to get at least 20 X eyepieces... atm I´m working with a max. of 40 X too. That makes it even harder to ID those properly. Fortunately I collected mostly Neriene and Linyphia which are not that small. At smaller species it gets quite hard, like the 1-2 mm Meioneta or Centromerus.
The problem I´ve got is getting them to genus level: The keys are based on the presence/absence and position of bristles and trichobothria on leg-segments. Those are likely to break away making an ID to genus level almost impossible. But when I´m at genus level it works out quite well.
When I need 5-10 minutes (depending on the family/genus - imo Pardosa are also quite hard to ID) for an ID of other spiders, I need at least 20 minutes for Linyphiidae
Earlier this year (february) I set up some pitfall traps and collected some interesting species (e.g. Scotina celans and Walckenaeria antica).

EDIT: Going to let you know when the key is online

 

[jsloan]

imo Pardosa are also quite hard to ID

I know what you mean. There are more than 20 species of Pardosa in Alberta, and I haven't got them figured out yet either.

EDIT: Going to let you know when the key is online

Great! I'm looking forward to seeing it. Thanks.