One of the main marks given to me by Hugh McGuinness was the sharp bend of the AM line as it nears the costa. He originally said that was a surefire mark for obscuripennis. Since then, he's had a chance to go through the collections at the USNM and he now says his surefire marks aren't exactly surefire anymore. Jason Roberts told me not long ago that some serious work needs to be done on Zanclognatha and in the meantime, we should hold off trying to ID some of these similar Zanclognatha spp. with photos. Here's what Hugh posted on Facebook after his visit to the USNM.

"OK so I looked at drawers of both Zanclognatha cruralis and obscuripennus, and I could find no marks that always work to diagnose them. After twenty minutes of going bleary eyed, here is what I wrote in my notes: "In general, obscurpiennis is more gray brown, and it is smaller. Sometimes the light colored st line is without a shade on the proximal side, which seems to never be the case with cruralis. The st line is often bright white or luteous, but some cruralis can show this. I did not notice that the pm line was slightly wavy as is often claimed as true for obscuripennis. The pm line was equally straight in both species." If one has a collection in front of them, most fresh moths can probably be determined based on ground color, but I doubt that worn specimens can be determined."