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Calathus gregarius? - Calathus gregarius - male

Calathus gregarius? - Calathus gregarius - Male
Ancram, Columbia County, New York, USA
September 29, 2014
Size: ca 11mm
Using Bousquet, I'm coming out at C. gregarius, rather than C. opaculus, based largely on the elytra being somewhat shiny (and not C. ingratus because of the pronotum). Bousquet lists C. gregarius as one of the common Northeast species and, indeed, we've recorded several which we have attributed to this species.

And yet looking at the Bugguide pictures, I see more C. opaculus logged, and those have varying degrees of apparent shininess. My questions are - Is C. opaculus indeed the common species elsewhere? And, for those of you who look at ground beetles regularly, are these elytra shiny enough to qualify as C. gregarius? They're not as shiny as the pronotum, but I wouldn't describe them as "dull" either. Any thoughts? Unfortunately, I don't have a C. opaculus reference specimen.

Moved tentatively

could be either
It is, of course, difficult to judge the "shininess" from a photograph due to variations in lighting and such. But, it does seem to be somewhat shiny on the elytra, which is consistent with gregarius.

this is a male, so shouldn't be hard to confirm ID...
...through dissection; opaculus looks like a better match to me --hope our experts chime in

Moved from Beetles.

Moved from ID Request.

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