Beetle - Agonum palustre

Definitely palustre, I think

Moved from Subgenus Europhilus.

… Curt Harden, 22 October, 2018 - 2:53pm

Moved

Moved from Agonum.

… v belov, 22 December, 2017 - 12:52pm

Moved

Moved from Agonum palustre.

… John Rosenfeld, 30 June, 2017 - 3:13pm

Why do forebody and elytra show same dark color?

I would have expected palustre to show elytra brownish in contrast to blackish forebody. This is apparent in some BugGuide examples. Coloration of course can be altered in so many ways: photographic influence, temporary darkening of integument while still wet, previous exposure to pitfall fluids, etc.

… Peter W. Messer, 29 June, 2017 - 9:10pm

The exposure

I added another shot with different exposure settings and the contrast is more evident.

… John Rosenfeld, 29 June, 2017 - 9:45pm

Who knew!

Thanks for now. I may want to return here for some crunching of the anatomic facts.

… Peter W. Messer, 30 June, 2017 - 1:39am

I would like that

I'm still vague on a lot of terminology and it's difficult to find clear definitions of a lot of anatomical features. I will probably dissect it, though I don't have access to any genital diagrams. Literature on beetles often seems rather hard to obtain.

… John Rosenfeld, 30 June, 2017 - 7:21am

Best sources for A. palustre and rest of northeast carabids

are Lth & YB2010. The former addresses many φ; on p1119 in particular for palustre.

… Peter W. Messer, 30 June, 2017 - 7:42am

Thanks

I obtained a copy of YB2010 from the publisher recently and that is what I used to key this. I can't find Lth online, is it available anywhere? I also looked for Hieke 2000 and couldn't find it. I've noticed a lot of literature on beetles seems to be on sites that require a paid subscription.

… John Rosenfeld, 30 June, 2017 - 8:05am

I've had much luck with interlibrary loan at my local library

in obtaining either hard copies or PDFs. They get the stuff either from university libraries in your state or else they already have subscriptions with several online academic resources (JSTOR, etc). I found it helpful to be friendly and enthusiastic with the reference librarian. I don't know if Lth is online as it was once. You might pose that question at a BugGuide site with more exposure than this tiny thread.

Frankly, I wish the second image showed even paler elytra. Makes me wonder about its true identity.

… Peter W. Messer, 30 June, 2017 - 1:13pm

I dissected it

Hopefully that will allow a definitive diagnosis. I'll have to try my local library, thanks for the tip.

… John Rosenfeld, 30 June, 2017 - 2:49pm

Sorry, I've not yet studied

male genitalia in palustre. Also, no figure for palustre in Lth, just a mention that the median lobe looks like that of a similar figured species.

… Peter W. Messer, 30 June, 2017 - 3:03pm

Do you have similar misgivings with this one?

If so I'll move it to genus.

… John Rosenfeld, 30 June, 2017 - 3:16pm

Yes,

that one falls into the same situation. Perhaps later this week I'll review the species complex surrounding palustre of which I have the essential synoptotypes.

… Peter W. Messer, 30 June, 2017 - 5:16pm

Within the Agonum sordens complex I favor

A. retractum on the basis that you say E m/s is stretched; basal three antennomeres appear pale; P more quadrate (elongated in palustre); Eyes prominent (flattish in palustre); E darkish (yellowish brown as in palustre). Final proof is of course physical exam by expert. However, you may now feel more confident in rechecking.

… Peter W. Messer, 1 July, 2017 - 2:50pm