ground beetle - Bembidion egens

maybe...

Yes, this might be B. egens. (It is not B. nogalesium, which is paler.) However, it is also very possible that B. cognatum and B. egens are synonyms, in which case this is probably B. cognatum. I call this species "Bembidion cf cognatum". There are a bunch of species of Furcacampa in Arizona, and they (plus the Mexican ones) will need to be revised before we can put names on them.

… David Maddison, 13 September, 2010 - 8:16pm

An interesting situation

in which potential synonyms are currently assigned to different subgenera, i.e., B. egens in Furcacampa vs B. cognatum in Notaphus. Obviously one of those associations has to be wrong for synonymy to occur. Such apparent "gross" discrepancies in taxonomic placements by previous authors underscore the difficulties facing modern carabidologists venturing into our southwestern Bembidion fauna. If not you David, who else is there that could tackle such difficult groups in our lifetime? Thank you so much for sharing your thoughts!

… Peter W. Messer, 13 September, 2010 - 9:33pm

Thanks Peter

Your efforts are really paying off, getting info out on the web about many species that are hard to find info on.

… tom murray, 20 July, 2008 - 4:00pm

Bembidion egens

tentatively based on my microscopic examination of this specimen. Bembidion egens Casey, 1918 is reported only from AZ & NM. It is a species difficult to distinguish from very similar AZ-MX species B. nogalesium Casey, 1924 based on little more than my review of the original taxonomic accounts by Casey. Sadly, I am not aware of any modern key that compares these two species. Also I found no other images on internet. According to my interpretation of the Casey descriptions, here are some criteria that might be useful for B. egens: Elytra with more distinct pale pattern and weaker impressed elytral striae; Pronotum base somewhat broader, with parallel hind angle section longer and with weak but distinct carinae. Thanks Tom.

… Peter W. Messer, 20 July, 2008 - 3:48pm