Araneae - Chrosiothes - BugGuide.Net

Moved

… Mike Quinn, 15 February, 2016 - 1:39pm

Moved

Moved from Spiders.

… Mike Quinn, 15 February, 2016 - 11:44am

possible Chrosiothes (Theridiidae)

I think Lynette may have been right in her comment years ago that this could be a Chrosiothes. I spent some time recently going over the genus and it really seems to fit. Right down to the "thick" legs and retrolateral tubercles on the patellae/knees which are described for the genus (I can see one of the tubercles in this image on the left leg IV, and can see more of them in the second image).

The abdominal pattern is extremely similar to Levi's drawing of C. portalensis, which is also described as having the proximal half of the femora pale, like this one. That species is recorded from Arizona to Mexico; couldn't find any records for Texas, but maybe that's not such a long shot?

I made a cheat sheet for comparing the 7 species in our range, but I didn't include genitalia since it wasn't applicable in this case. It's in my google drive here.

Mike, was this a collected specimen that can be verified/compared to C. portalensis under a scope or whatnot? It would be a new species for the guide, or in the very least our first female Chrosiothes.

… Mandy Howe, 15 February, 2016 - 8:40am

looks like a match for Chrosiothes jocosus (Gertsch & Davis)

look again at your male image for Chrosiothes jocosus (Gertsch & Davis), Fig. 9. it fits the pattern and distribution, no?

… Mike Quinn, 15 February, 2016 - 11:01am

Hmm, not sure

These spiders are less than 3mm, with adult males usually 1-2mm... I don't see any indication of yours being a male (no enlarged palps, not even swollen in the immature stage), so I think it's a female, meaning that we would be comparing female abdomens.
I thought the markings to be a better match for C. portalensis, fig. 22 on the cheat sheet, with the two horizontal black patches, and the black area on the anterior abdomen. Plus C. jocosus females have major humps on the "shoulders" whereas C. portalensis is more subtle/rounded. The color photo under C. portalensis is taken from a different angle than the drawing, and also is likely faded from preservation.
I guess C. jocosus would make more sense based on range, but that C. portalensis drawing sure has me wondering.
Is this a collected specimen that can be checked under a microscope if it's mature?

… Mandy Howe, 15 February, 2016 - 12:08pm

yes, I probably jumped the gun on moving it to sp-level ID...

I didn't believe I coll'ed the spmn (past the time I held it for photographic purposes)... I'll ask Val Bugh if she has any insight into this spider (though I suspect I asked her once before).

Thanks much for everyone's input.

… Mike Quinn, 15 February, 2016 - 1:43pm

Hopefully someone with personal experience with these will be able to tell us more someday. I'm going to ask around and see if I can convince anyone to take an image of a couple of these from museum collections, just so we have a better idea of what they look like in comparison to the diagrams. Cool spider, glad you posted it!

… Mandy Howe, 18 February, 2016 - 11:43pm

lumpy abdomen

I have been trying to think of all the lumpy abdomens I've seen. I looked at all the spiders you've posted from Travis County, but no help there. Then I looked at all the spiders you've posted & no help there either. I looked at other people's posts from Travis County & browsed through the orb weavers and came up with a few more ideas.

Phoroncidia americana not likely, legs are already too long
Gea heptagon - not likely
Acanthepeira - I doubt it
Gasteracantha cancriformis - nope
Uloborus - doubt it
Cyrtophora - nope
Gea - interesting but doubtful
Kaira - I have no idea what a juvenile might look like
Micrathena - nope
Ocrepeira - nope
Scoloderus - never seen a juvenile, but highly doubtful
Verrucosa - possible I think
Wagneriana - not sure

… Lynette Elliott, 5 January, 2015 - 8:04am

Maybe bumps don't mean anything

It could also be that the spider is malnourished or dehydrated. They can get bony. The abdomen looks too big for this to be the case, but who knows how big it should be.

Oh wait! In the shot from the front, the abdomen looks flattened vertically. This could very well be a dehydrated/emaciated spider. The lumps could be a distraction.

… Joe Lapp, 5 January, 2015 - 9:00pm

theridiid?

I'm just now noticing the lack of spines on the legs. It seems to me that even juvie araneidae have spines. Maybe this is a theridiid?

… Joe Lapp, 5 January, 2015 - 8:58am

lumpy distraction

That would be frustrating. I have looked through the cobweb spiders, but ? I guess we'll just keep thinking this one over. =]

… Lynette Elliott, 6 January, 2015 - 7:58am

More angles

Do you have any more angles of this one?

… Lynette Elliott, 18 October, 2012 - 10:13am

Acanthepeira?

What does an early instar Acanthepeira look like? This spider reminds me of the adult. Notice how the abdomen isn't smoothly round?

… Joe Lapp, 4 September, 2012 - 9:06am

no I would doubt Acanthepeira

My reasons would be... I can't image the carapace shape & eye arrangement wouldn't show up in the juveniles (& Acanthepeira has a very distinctly shaped carapace). The legs do seem to come close in coloring though.

… Lynette Elliott, 4 September, 2012 - 9:11am

I just looked at the carapace on Acanthepeira. You're right. Not a good match.

… Joe Lapp, 4 September, 2012 - 9:14am

Moved to spiders

Moved from Araneus. I think it's just too hairless (esp legs) to be Araneus. The eyes don't look right either. Those legs (color & size) remind me of Cyclosa for what that's worth. They don't seem hairy enough to be that either though. I was looking through the cobweb spiders and came across genus Chrosiothes. (some Chrosiothes have been transferred from/to Theridiotis/Dipoena/Episinus/Euryopis/Phoroncidia/etc. so we'd have to look around a bit I think)

Here's a description of Dipoena jocosa (now Chrosiothes jacosa) by Gertsch & Davis from 1936. (New Spiders From TX) 2.25 mm, "Carapace dark reddish brown, clothed sparsely with short pale hairs. Sternum dark reddish brown... Integument of the legs pale yellow, but the bright color masked more or less completely by brown, the basal half of the first femur pale, the distal half of the femur and the remaining joints of the first leg mainly brown. Other legs as the first but the dorsum of the joints with an inconspicuous pale band. Abdomen mainly gray, the dorsum with a broad white transverse stripe between the shoulder humps, the venter with a broad triangular dark band which encloses a white maculation."

… Lynette Elliott, 2 September, 2012 - 11:05am

I suggested that Araneus was possible to Mike in email because there appears to be a transverse foveal groove. Also, do we know that early instar Araneids necessarily have strong macrosetae? I don't think we can judge regular setae cover from such a narrow DOF macro.

I have no clue what it is. I don't know what to expect of early instar Araneids. FWIW, I *do* think I see a nice covering of setae on the abdomen. Wouldn't that rule out Theridiidae?

… Joe Lapp, 4 September, 2012 - 8:22am

hairy legs on orbweaver spiderlings

Yes, in my experience orbweaver spiderlings have hairy legs. Here are a few examples

Also many cobweb spiders have hairy abdomens. Compare with

That being said I don't know what this spider is either. =] There's also something about the shape of the legs that keeps me thinking cobweb spider.

… Lynette Elliott, 4 September, 2012 - 8:53am

Gotcha. I do see hairs all over the legs on the present spider, but they are no where near as conspicuous as those on your example specimens. (The hair nubs are all you get with overexposure like this.) On the other hand, the abdominal hairs I'm seeing on the present specimen seem stronger than those of your example Theridiidae. Surely that double-hump limits who it can be, but I guess we've got them among all the Orbiculariae. Thank you for the effort finding those example thumbnails!

… Joe Lapp, 4 September, 2012 - 9:02am

Did seem to have a "blocky" abdomen

My impression in the field was definitely of a blocky abdomen trunkated in front, as seen in this spider:

Acanthepeira sp.

… Mike Quinn, 4 September, 2012 - 9:11am

Good find Mike! But I think your find also disproves the match: at 4mm, it's about the same size as your spider and already having all the significant Acanthepeira characters, unlike the present specimen.

… Joe Lapp, 4 September, 2012 - 9:15am

lumpy spider

How large is this spider & what habitat did it come from? I'm leaning toward some sort of cobweb spider? I'm certainly not sure though.

… Lynette Elliott, 2 September, 2012 - 9:51am

Interesting! When I first saw it I thought it was

going to be something like Phoroncidia, but I couldn't find anything in SONA that looked like it.

… john and jane balaban, 2 September, 2012 - 10:11am

Well you stumped us with this one, Mike

We'll be eager to see what suggestions you get!

… john and jane balaban, 1 September, 2012 - 1:30pm

Moved

Moved from True Spiders.

… Mike Quinn, 1 September, 2012 - 12:36pm