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Carabidae? dorsal - Tachys

Carabidae? dorsal - Tachys
Florida Canyon, Santa Rita Experimental Range, Pima County, Arizona, USA
July 25, 2013
Size: 2.22 mm
Download high resolution image here.

I collected this small beetle near Florida Station, Santa Rita Experimental Range during Bugguide Gathering 2013. It has features of a Carabid, despite being much ligher in color than most. Perhaps it is coming out of a teneral state.

This image is a CombineZP processed stack of 208 images with a 5.6 µm step taken with a Nikon CFI60 10×/0.25 ∞/0 mm microscope objective + Nikon 135mm F/2.8 AIS telephoto lens + Nikon D300 camera (magnification 6.75×; technique described here).

Images of this individual: tag all
Carabidae? dorsal - Tachys Carabidae? lateral - Tachys Carabidae? ventral - Tachys Carabidae? anterior - Tachys

Moved from Tachys vorax.

Terry Erwin reports, "The Arizona species in question is NOT Paratachys vorax and it will take me a while to get you a name on it." And, in a follow-up, "I know it is not P. vorax because I have a homotype of that and I compared the pic with the specimen; they are not even close".

so be it --thanks again, Kollegen

D.R. Maddison says, Paratachys sp.
Moved from Trechini.

Sherlockian armchair conclusion: Tachys (Paratachys) vorax
Of only three species of genus Tachys confirmed for AZ by Bousquet (2012), only one occupies subgenus Paratachys. The two subgenera Tachys vs Paratachys can be separated by position of the anterior setigerous puncture atop the elytron, that is, in contact with stria #3 for Tachys vs near stria #4 for Paratachys. High resolution photo supports the latter case and dorsal coloration more or less fits the type specimen shown here.

I would accept the specimen for photo-vouchering if that is deemed important. Beautiful imaging here of course!

T. vorax
Thanks for the help. According to Bousquet 2012(1), the only member of subgenus Paratachys reported in AZ is T. vorax, where it was collected on the Gila River. This is in southern AZ, like the subject beetle. My images closely resemble those of T. vorax in the MCZ Database. That's reasonably good evidence that that's what it is, but expert confirmation is appreciated.

Arizona might be home to an undescribed Tachys?
See my update for a similar appearing Tachys under BugGuide #1718913 which I recently decided was NOT T. vorax. It's sad we no longer have Terry Erwin to help us in such matters.

Moved from Beetles.