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Photo#164269
Elaphropus dolosus - Elaphropus ferrugineus

Elaphropus dolosus - Elaphropus ferrugineus
Tippecanoe County, Indiana, USA
September 15, 2005
Size: 2.5 mm
Based on Peter's input, this is E. dolosus. My initial guess was E. granarius.

Moved
Moved from Elaphropus dolosus.

Thanks
Thanks for the help Peter. Type specimen can be seen here.

continued message (what a mess!)
However, your 2mm does favor E. granarius (all

 
can't get 2nd part of message through, why?
can't get 2nd part of message through, why?
However, your 2mm does favor E. granarius (

Elaphropus dolosus
is favored by relatively long elytra compared to the distinctly shorter (fatter) elytra in E. granarius. Also here the pronotum is relatively narrow with sinuate margins, not the wider, shorter, and roundish (non-sinuate but constricted) pronotum expected in E. granarius. Continued in next message:

 
Reconsider to "Elaphropus ferrugineus (Dejean)"
based on apparent reduced eyes, uniform pale coloration, and inflated elytra with 2nd striae impressed + 1st stria punctate.

 
"Elaphropus ferrugineus (Dejean)"
Peter, I think you may be right. This specimen and another from KY I also had under E. dolosus seem to fit this species.

What length of the first striae is punctate? On this one it is only for about 2/3 the length.
Are the reduced eyes short in length as suggested in Tom's photo, or just more flattened and less protruding, which is what I am seeing in my specimen.

 
Answers in behalf of Elaphropus ferrugineus:
first stria "2/3" punctate is sufficient; eye both shorter and less protruding compared to related species; see excellent key by Yves Bousquet with a close-up of the eye (p.157) in his Illustrated Identification Guide to NE North American Ground Beetles (2010).

Brad, I hope you have above book (either personal or departmental) which is essential for your ongoing good work on Carabidae.

 
Thanks Peter
I don't have Yves's book yet. Its too bad there isn't an "ebook" option for this book, as some other titles from that publisher do.

 
Okay, leave as "Elaphropus ferrugineus"
for now. Separation of the two species are quite clear when specimens are compared in hand. Yes, I can certainly examine this one if you still feel uncertain.

 
My image guessing not over! Now consider "Porotachys bisulcatus"
which superficially looks like a pale E. ferrugineus with inflated elytra, but easily distinguished from latter by a pair of sharp circular pits on mentum. Brad, please check that out. Also in P. bisulcatus, more elytral striae are well impressed and punctate. Eye also somewhat larger and without the swollen temple posteriorly. I have specimens of both species to compare in case you need more information.

 
No pits on mentum
There are no pits present on the mentum, so this cannot be that species. I may send this specimen to you someday for unequivocal determination.

 
continued message:
However, your 2mm does favor E. granarius (all

 
try again
However, your 2mm does favor E. granarius (

 
Brad, I'll send you my full reply privately
I'm giving up!