06 de septiembre de 2017

Links to Undescribed Spiders

This page provides links to searches for undescribed spiders on iNaturalist.

The "tag name" field has become the place to give undescribed species temporary names. Click on the following tag names to list iNaturalist records tagged as an undescribed species.

Maevia sp. 'yellow cephalon' (under revision by G.B. Edwards)
Mecaphesa sp. 'black tibial spot' (under revision by Nicole Miller and yours truly)

Publicado el 06 de septiembre de 2017 a las 05:31 PM por arachnojoe arachnojoe | 0 comentarios | Deja un comentario

03 de septiembre de 2017

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.)

Publicado el 03 de septiembre de 2017 a las 02:00 AM por arachnojoe arachnojoe | 21 comentarios | Deja un comentario