Hi, John-

On what basis are you distinguishing this from A. proxima? Looking at the one ventral shot, it's not even clear to me whether this is a mature specimen.

Dondale and Redner even say that the paired black spots on the posterolateral margins are not diagnostic for the genus (if rather typical).

-Kevin

Yes it may be immature, I'm not sure. It was found in the typical Araniella web, roughly two inches across, hung over a slightly folded broad leaf, with the spider sitting inverted in the web and roughly in the centre. I think that when it is said that the six-spots are not diagnostic it means only that their absence cannot exclude it being A. displicata, but I am more than happy to be corrected if I’ve misinterpreted this. The following quote suggests that the spots are a useful marker: 2002. The Journal of Arachnology 30:527–562, Page 546: "Two or three pairs of round black spots dorsally on posterior of round yellow to green abdomen (Fig. 147); max. 8 mm; 2 sp., Alaska to S U. S. . . . . . . . . . Araniella”. Since this animal clearly has the six rear spots and there are only two species in N. America, A. displicata and A. proxima , it would be helpful to know whether A. proxima has six spots or whether there are other obvious morphological diffrences? The reference that you gave below (Rainer Blanke, Zoologica Scripta, 11: 287-305, 1982) does maintain that A.displicata is separate from the others, but as far as I can make out (it is in German) this is on the basis of genitals, so that is unfortuately rather unhelpful for live specimen photography. Since there are only two reported Araniella species in N. America the question is whether these can be distinguished by gross appearance or not, with at least some confidence if not absolute certainty.

Dondale writes that these paired spots are not only found in "specimens throughout the genus" but also that they may be found in "specimens of some species of Araneus". Then, again, in their description of A. displicata, they write "the possession of three (or four) pairs of small black dots on the abdominal dorsum is of some diagnostic value (Sacher 1990)."

-K

But on further surfing it seems A. curcubtina is also found in N. America, (but not thus far in Quebec), so that complicates things.

http://www.canadianarachnology.org/data/spiders/15325

We're discussing it on this image http://bugguide.net/node/view/248605. Our genus level info page says there is only one species, I believed it, and moved ALL the images down for house-keeping reasons. Now it seems the info page is wrong.
http://bugguide.net/node/view/8426

will show that the guide page says only one species in the US, which wouldn't apply to this example.

I agree with the other comments- the guide page is misleading.

but I think it also turns out that there is more than one species in the US

Yes the page is misleading; both the Neartic spider database and the web site "araignees du Quebec" list two Araniella species (displicata and proxima). Of these, A. displicata seems much more common, however there is virtually no internet-accessible information as to what A. proxima looks like. I found only one tentatively identified image (from Finland).Although it is possible that an absolute definition of its identity might require looking at the genitals under a microscope, there may or may not be enough difference in gross appearance of the two to be highly confident.

Can you tell which of the images currently on this species page belong here, and which should go back up to genus. It is likely that many images were "IDed" by the fact that the info page claimed there was only one species. If they can't really be identified should they all go to genus, or should we make a "species group" for all of the images that can't be IDed? Maybe some can be IDed, but how many?

Hi, John-

Perhaps someone can distinguish these based on appearance, but Dondale (and also Michael Roberts, I think) make the point that a genital determination is necessary. I think that the genus level is probably fairly safe, but as we were just talking discussing in the Nearctic Forum, the Araneidae are always good for a surprise when it comes to appearances.

My own recent experience was with a not quite mature Araniella displicata. I was fairly certain of the identification, having seen the beginning of the scapus, etc., under the microscope, but the arachnologist in whose workshop we were insisted that the farthest I could go was "Araniella cf. displicata". :-( (Of course, we have several more Araniella species here in Europe.)

-Kevin

Well, if we had a subscription to Blackwell Synergy...

Abstract: Untersuchungen zur Taxonomie der Gattung Araniella (Araneae, Araneidae)

Rainer Blanke, Zoologisches Institut der Universität, Kornblumenstraße 13, D-7500 Karlsruhe, GFR.
Abstract

Morphological and ethological criteria were used in studying the taxonomic relations between different forms within the genus Araniella. Criteria for a diagnosis of all species and subspecies of the genus are given. A. opisthographa (Kulczynski, 1905), A. cucurbitina (Clerck, 1757), A. proxima (Kulczynski, 1885) and A. maderiana (Kulczynski, 1905) form one group of sibling species in the narrowest sense, A. alpica (L. Koch, 1869) and A. inconspicua (Simon, 1874) a second distinct one. A. displicata (Hentz, 1847) seems to occupy a relatively isolated position. A. cossoni (Simon, 1885) is regarded as a synonym for A. cucurbitina.

Since proxima is lumped together with cucurbitina, it would seem that your spider is most likely disciplinata, wouldn't it?

You might also ask in the Nearctic Forum: http://forum.canadianarachnology.org/

-K

hi Kevin;
Thanks very much for your thoughts tracking this down. You are certainly right; prompted by your comments I made another search for images of A. proxima; there are still not many, but those that are a quite different form this one.