About the field "Holding bin (spider)"

The observation field "Holding bin (spider)" provides the most specific ID that is possible for a spider when that ID spans multiple formal taxa. It may be thought of as a placeholder until a better ID can be made (if ever). The allowed values are currently as follows:

Araneus gemmoides/illaudatus
Castianeira crocata/descripta
Mecaphesa asperata/carletonica
Pending Additions
other (see comments)

We largely determine spiders (and most arthropods) to species by their genitalia. Sometimes we even need genitalia to identify the genus. Users rarely post genitalia to iNaturalist, so we have to identify iNaturalist specimens by field-observable characters.

The groupings available to us by field-observable characters do not perfectly overlap with the groupings available to us by examining genitalia. That is, the best IDs we make from photos do not always overlap with the IDs we can make by examining specimens. Because iNaturalist only allows us to ID to formal taxa, the official iNaturalist ID can't always capture the best available ID.

For example, after examining dozens of female specimens of Misumena vatia and Misumessus oblongus (crab spiders), I found no morphological characters that always distinguished them, except for genitalia. Both species come in all-white forms, and when they do, there may be no way to distinguish their photos. There are 126 described species of thomisidae north of Mexico, and we can know that a specimen is one of two of these species, but the iNaturalist ID only allows us to indicate thomisidae, asserting that it is one of 126 species.

The field "Holding bin (spider)" names a complex of multiple taxa to which a spider belongs when no single formal taxon captures the specificity that is actually possible. It's values are invented groups listing multiple taxa. We've borrowed the term "holding bin" from BugGuide, reflecting the ideal that we might one day refine the ID.

Let's use the comments on this page to decide what holding bins (field values) are available. The values should be groups that can theoretically be determined from photos, not simply groups that the lay public finds confusing. BugGuide has been capturing such artificial groups for a while and can serve as a guide for us. (See also "Holding bin (plant)", "Holding bin (birds)", or the list of all holding bins.)

Posted by arachnojoe arachnojoe, September 03, 2017 02:00


Nice idea, Joe. If I'm understanding correctly, one that comes to mind currently that'd be useful is Araneus gemmoides/illaudatus.

Posted by claggy almost 5 years ago (Flag)


One that comes to mind right away is Eris/Metaphidippus/Pelegrina/Phanias

I'll add more as I think of them. Thank you!

Posted by tigerbb almost 5 years ago (Flag)

Thanks for those ID complexes! Okay, before we tag too many specimens, we should probably be sure we're happy with the field name. Here are the possibilities I can think of:

Best ID complex
Best ID grouping
Best field ID
Improved ID
Interim ID
Holding bin (a term BugGuide sometimes uses)

I'd like the name to suggest it isn't a field people can fill out willy-nilly, though. I'm also a fan of terms saying what they are, so people wouldn't necessarily have to read this blog to make an educated guess.

Posted by arachnojoe almost 5 years ago (Flag)
Posted by charlie almost 5 years ago (Flag)

I've found two pages on BugGuide that refer to these multi-taxa complexes as "holding bins." I'm renaming this one for consistency.

Posted by arachnojoe almost 5 years ago (Flag)

Thanks. I updated mine too. I like that category name, it shows that it is taxonomically informal but also a reusable category

Posted by charlie almost 5 years ago (Flag)

@bouteloua did some testing and found that we can maintain an unlimited number of values in a field that provides a drop-down list, provided that we constrain the valid values. I've done so for this field. You may select "other (see comments)" to make a temporary assignment to a value not yet present in this field.

Posted by arachnojoe almost 5 years ago (Flag)

yeah they populated the bird list with a billion options and it still works. https://www.inaturalist.org/observation_fields/7188 So I guess i will go that route for plants too. I made an other also

Posted by charlie almost 5 years ago (Flag)

@braytonidae, I'm thinking that we shouldn't often be IDing to better than the Mecaphesa/Misumenops complex for thomisids in Mexico. It may be that we can only do better when we know the species. It's not yet clear to me what Misumenops are in Mexico -- several specimens that I've seen so-labeled were actually Mecaphesa.

Posted by arachnojoe almost 5 years ago (Flag)

Wow, looks like we've started a trend, @charlie! I find myself partial to naming the group in the plural:

Posted by arachnojoe almost 5 years ago (Flag)

Yeah maybe plural would have been better, but i think if I change it, it may break my links again? But yeah it is awesome that this is taking off, so satisfying!

Posted by charlie almost 5 years ago (Flag)

oh wait, the link is numerical so i think i can change it? I went ahead and changed it to plants

Posted by charlie almost 5 years ago (Flag)

I tried changing it to spiders. It broke searches for all previously tagged spiders, which could still only be found under the prior name. So I changed it back to "(spider)". Not sure what to do.

Note that it makes more sense to say "Spider holding bin" than "Spiders holding bin," so it's still a reasonable field name.

Posted by arachnojoe almost 5 years ago (Flag)

ugh. i changed mine back then too.

Posted by charlie almost 5 years ago (Flag)

I'm thinking that the term "holding bin" also works well for undescribed species. The open-ended field "tag name" is the current convention for indicating undescribed species.

Posted by arachnojoe almost 5 years ago (Flag)

Hmm. That theridiid group is an interesting one. The situation is that, given photos of the spiders from appropriate angles, we actually can distinguish these genera. It's just that sometimes we don't have a good angle.

I guess we do need to be able to say, "Best ID possible from these particular photos" rather than "Best ID possible from photos of this particular specimen." This extends my thinking about the use of this field.

Posted by arachnojoe almost 5 years ago (Flag)

Ah. I need to get more familiar with those genera. I haven't been clear from Bug Guide how individuals were being differentiated or not differentiated.

Posted by tigerbb almost 5 years ago (Flag)

I've been thinking about this. Sometimes a particular photo only allows us to say that it's either a clubionid or an anyphaenid, or a lycosoid or an agelenid, or a philodromid or a thomisid. The problem is that the photo is too fuzzy or the angle of the shot isn't helpful or the resolution is too poor. There might be an infinite number of combinations of confusable taxa under these conditions.

So in the case of these theridiids, I'm inclined to wait until I better understand the problem with distinguishing them. If sometimes there isn't a reliable way to tell them apart in the field or in photo, that would merit creating a holding bin. If the problem is always in the photos themselves, I'm inclined to let the ID go unrefined.

Posted by arachnojoe almost 5 years ago (Flag)

Been a long time here, but FYI I added another value here for an interesting and (I think) distinctive looking animal I found a few of while digging through all the Texas spider observations. I may add some more values here if it seems appropriate. I didn't want to create what was essentially a duplicate "Holding bin (spiders2)" observation field so I had a curator add to your existing one. Hopefully you don't mind Joe. :-)

Posted by jgw_atx over 1 year ago (Flag)

Please do! I don't think these holding bins have been getting much use. Thanks for helping.

Posted by arachnojoe over 1 year ago (Flag)

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