Update: I found that I had a second photo of this individual - but it's almost identical to the first image; however, I've added some crops of the 2nd image, and added some new text highlighting yet another apparent anomaly for nahuana - the new text is colored mauve:
This male Dancer Argia sp. was on Limpia Creek in Davis Mountains State Park, Jeff Davis County, Texas on July 31, 2004; it appears to be Aztec A. nahuana, but note:
- segments 8 - 10 are blue but with a complete thick black ventro-lateral line - nahuana typically has S8 with only a distal partial black line, and S10 with none (rarely a small incomplete black mark).
- the exact shape of blue on segment 6 is atypical in that has a long dorsal point - nahuana typically has S6 with the blue shaped identically to that on segments 5 and 4; also a thin black edge is visible laterally along the bottom of the dorsal blue of S6, indicating that there is no blue below this point - nahuana has the blue on S6 continue onto the ventral surface.
- segment 7 is black apart from a blue basal ring that appears incomplete ventrolaterally - - nahuana typically has S7 with at least a complete blue basal ring from which blue extends ventrally (and sometimes dorsally).
- on segment 2 the black lateral mark is a thick lateral band, expanded at both ends - nahuana typically has S2 with a single triangular black mark distally, and sometimes a separate small mark basally.
On the images of nahuana that I have examined, I cannot find any of the above features, let alone all four - ?:
images from 2nd photo:
note that S4 and S5 show the blue disappearing from view latero-ventrally, while S6 shows the blue ending laterally: