natev's Journal

At the time of this writing, there are 74,000 observations of Misumenini in North America, 41,000 of which still need identification. There is great information on how to tell the species apart on BugGuide, contributed by the great Joe Lapp and several others, but this information is currently spread across at least 4 pages. I will try to distill it to one, easy to understand page.

Subsequent journal posts will discuss how to identify the Misumenini of Central America and Mexico. In the US and Canada, there are only five Misumenini genera and 22 species.

The five genera are Misumenoides (1 species), Misumena (1 species), Misumessus (3 species), Mecaphesa (18 species), and Misumenops (1 species).

Here is a simple key that will get you to the right answer 95% of the time. As such, please be very cautious when identifying with this key, especially when distinguishing Misumenops from Mecaphesa.

Dichotomous key for Misumenini in the United States and Canada:
1a Eye region with a white or yellow carina…Misumenoides
1b Eye region without a carina (may have a white line or mark that is not a carina)…2

2a Carapace with macrosetae (may be worn off in older individuals, and often do not show up on smartphone photos)…3
2b Carapace without macrosetae…4

3a Eye region with long macrosetae, rest of carapace with relatively short macrosetae; carapace translucent brown or tan, often with two brown or red-brown stripes; only found in Florida …Misumenops bellulus
3b Eye region and rest of carapace with relatively long macrosetae; carapace pattern various; found throughout North America…Mecaphesa

4a Carapace unmarked, translucent, shiny, often with a reflective spot…Misumessus
4b Carapace marked, opaque, often with a median white or yellow stripe of powdery pigment…Misumena vatia

Glossary:
Carina: a keel-shaped marking
Carapace: the "head" of the spider
Macrosetae: long, thick hairs

ID Tips
Abdominal shape and pattern provide useful clues, but Misumenini are chameleons--they change their color and pattern, and often adopt the color or pattern you might associate with a different species. BugGuide has some good details about the abdominal patterns, but be sure to groundtruth those details with the carapace, which varies less.
The literature says that Misumenops has spines around the ocular region but not on the cephalic region (the rest of the carapace), while Mecaphesa has hair throughout the carapace, but the photos in the literature show Misumenops specimens with more hair than Mecaphesa specimens. More work needs to be done here, but it is still a good rule of thumb, it seems to be true most of the time.
Also, this key and these tips assume that you don't have a specimen and a microscope. If you do have a specimen and a microscope, use a published key to identify it. Right now, that's the only way to ID Mecaphesa species, for instance. Create an account with the World Spider Catalog and use that to download any primary literature on spider taxonomy for free.

Notes:

Some of the Mexican Misumenoides species occasionally show up on the US side of the border.

BugGuide and the World Spider Catalog mention two species of Misumena in North America, but one of them, Misumena fedelis, is probably just a color morph of a Mecaphesa species.

Bugguide and World Spider Catalog mention 3 Misumenops species; of these, only Misumenops bellulus is a credible species. More on that in a future post.

Other topics that will be covered in future posts: How to tell the three Misumessus species apart, how to identify the Mexican and Central American genera/species, and how to identify Mecaphesa species (spoiler alert: you often can't go beyond Genus level ID).

Thanks for the read. If you see something I messed up on, message me and I'll fix it.