On page 38 of that key, the range map #1 is a duplicate of map #6 on page 39. (M. navajo) The range for Myzinum carolinianum is listed as Florida to Texas, north to the Dakotas, Minnesota to Maryland.
All sightings of the females of M. carolinum are eastern only, so far. The groove on the 7th abdominal segment and also the coxa are very hard to see in most images of the males.

I had looked at the maps to see if maybe a copy-editor had made an inadvertent swap...but I hadn't thought to look for a duplicate map instead. Now that you pointed it out, it's clear that's what happened...good catch!

So the main question now is: Are Robert's (and Salvador's) finds truly range exensions? Or am I in error in identifying them both as M. carolinianum?

By zooming-in on Robert's 1st image here (via repeatedly pressing "Cmd-+" in a Mac browser, or "Cntl+" in a Windows one), I believe I can discern the medial groove in T7 fairly well. And at couplet 4 of the key, the "uniformly amber" vs. "hyaline w/ apical infuscation" distinction between the resulting two main candidates, quinquecinctum and carolinianum, seems pretty clear to me...as does the "dorsum of T7 with yellow" vs. "dorsum of T7 entirely black" discriminant.

But in Salvador's images I can't make out a medial groove on T7 ...and without that (and a appropriate view of the mid-coxa, as well as many genitalic details) Salvador's might key to any of confluens, dubiosum, frontalis, maculatum, or navajo and still fit range-wise!

I'll move Salvador's post back to genus, and inquire if he may be able to provide further diagnostic images...as he may still have the specimen.

Yes, those five species might be "it" for Arizona. I'm not sure.
BOLD Systems has a few species bins for this genus now! He should send his specimens there, since his images are usually excellent examples.

I've now read Kimsey(2009) more carefully than I had when I made my previous comments, and realize I can't see enough detail to truly discern the crucial "medial groove on T7" character in the 2nd couplet of the key there.

I now believe what I had thought was the groove is probably just "highlighting" corresponding to the small cavity between the two lateral lobes at the apex of T7. From Fig. 11 in Kimsey(2009) the "groove or crease" should extend further from the sinus of that cavity (perhaps all the way to the suture at the base of T7?). I just can't make out enough detail in the above image to really verify the key character.

In fact, I can't clearly discern that "T7 groove" in any of the current BG posts for males of M. carolinianum or M. quinquecinctum...which should both have the groove according to the 2nd key break in Kimsey(2009). I also checked out the BOLD Myzinum page, and I can't make out the critical "medial groove on T7" character in their M. carolinianum image either...click the thumbnail below to scrutinize that image:


BTW, reading the discussion & distribution info in Kimsey(2009) carefully...it turns out 8 out the 10 species treated there are recorded from AZ (all except carolinianum and obscurum). And 6 of those 8 are recorded from Cochise County (all but cocoritensis and fulviceps). Among the 6 species in Cochise County, one might try to use the ocello-ocular + inter-ocellar distances and the length-to-width ratios of the 1st & 9th flagellomeres to narrow down the candidate species...but I can't really discern ocelli here (or in most other current BG posts), and the flagellomeres are also usually difficult to see clearly. That leaves only wing vein color and infuscation pattern to go on.

So it seems these are indeed harder to ID from typical field photos than I had thought & hoped!