I'll tribalize it ;-)

would be okay as I see (in addtion to above characters) the expected recurved scutellar striae along posteriolateral margins. However, if those are truly a pair of distinct pits as suggested on ventral mentum and not just photograhic trickery, then this can not be Tachyta. Can you get a high resolution closeup of the mentum area?

I just discovered that mentum refers to the underside of the lower jaw in mammals :-)

the image is just a bit too blurry to be sure. Sorry to make you work! Have you seen the other "Tachyta" posted on BugGuide? They look a lot like yours. The "mentum" and "submentum" are distinct adjacent structures that are taxonomically important for separating groups and even species of carabids. I wonder if these terms ever made it to the BugGuide Glossary? The "submentum" is somewhat analogous to "neck", hence this saying amongst carabid people: "I'm up to my submentum in work!".

on this screen, the pitless mentum, staring Tachyta sp.

Our star's fame will likely be fleeting - doesn't yet have a last name!

has offered to take one and see if he can key it to species. I'm sending him some other stuff so this will be a bonus.

is Terry Erwin (1975) - "Studies of the Subtribe Tachyina Part III: Systematics, Phylogeny, and Zoogeography of the Genus Tachyta Kirby", Smithsonian Institution Press. It has excellent habitus drawings and closeup photos of details. You may want to pass this on to Brad in case he intends to only consult with Downie & Arnett (1996).

I favor T. angulata for the beetles Jim sent me. Pronotal shape fits well and the face between the eyes seems flat. I also noticed in Erwin's work that placement of the elytral setae differs between T. angulata and T. nana, but I don't know if this is a reliable character. In the specimens at hand, the rear discal setae lies behind the apex of the recurved stria, while in the illustrations of T. nana they are in front of the apex of the recurved stria.

is an astute finding by Brad Barnd which T. Erwin illustrates but does not otherwise acknowledge. My specimens of T. nana inornata (11) and T. angulata (4) are consistent with Brad's comment:

Rear elytral setae are distinctly anteriad to apex of recurved striae in T. nana inornata, but posteriad or equal to same in T. angulata.

However, my one specimen of T. nana kirbyi fits setae position of T. angulata. At any rate, the distinctly cordate/sinuate curve of pronotal margins AND proportionately long elytra shown in Jim's original image does fit T. angulata better than T. nana.

I have recent information that carabid authority Yves Bousquet (Ontario) now treats Tachyta inornata and Tacyta kirbyi as distinct species, thus replacing their former status as subspecies of T. nana. Acceptance of this taxonomic change now bodes well for the separation of just T. inornata from T. angulata based on position of rear elytral setae. The reliability of seta position for T. kirbyi is less certain, i.e., more posterior position in my one specimen against more anterior position in Erwin's illustration.

Boy, the collective effort to get an ID make on this little beetle was pretty amazing.

I've moved it there.

I'll be posting a tiny *blond* carabid shortly.

He and I get a great overlap in species since we live relatively close to each other.

Is there a bugguide glossary? I've never seen it. (Maybe it's a forum article?)

I collected several more of these little guys today but haven't photographed them yet. Maybe I'll luck out and get a really good underside view. Also, this one is in alcohol and could be fished out for another go with the camera.

here's a link the BugGuide Glossary. Patrick Coin had contributed heavily. Be sure to use the Info tab to see the content, after navigating through Taxonomy tab.

It's not on a ground beetle, but here's a image of submentum pits that should at least get you to the right neighborhood. In my limited experience, the pits on Carabids are a lot deeper and wider, but still can be difficult to see on such small beetles.

Lastly, D&A list only two Tachyta for our area (subject to errors and updates). T. angulatus Casey - "pronotum markedly constricted at base, frontal furrows indistinct", and T. nana Gyllenhal - "pronotum slightly constricted at base; frontal furrows distinct".

hope this helps,

If I visit there much I'll gradually learn something.

The New Hampshire checklist indicates a third species beyond the two you mentioned: T. inor*nata. However, on the Les Carabidés du Canada Web site they have a T. nana inor*nata, which I guess would indicate subspecies. Whichever one it is, I'd bet money on it being the same species as Tom Murray's.

I think I'll move this to genus but will still try for a better mentum view, maybe today.

In my area there's also subspecies: "Tachyta nana kirbyi". Let's try to also get a shot of a bembidiine with obvious mentum pits as Tachyta won't have them.

Tim, Thanks for the information about Tachyta in D&A. I won't guess which species based on above images as careful scoping of specimen is the only reliable way. I am relatively unfamiliar with tenebrionid anatomy, but my educated guess is that those pits might actually be on an extension of the prosternum. I see what appears to be the mentum & submentum (separated by a transverse suture) immediately beneath this prosternal process. Am I wrong?

Also, you are right about the pair of mentum pits being quite prominent when present in certain bembidiines. They are not obvious here thus further supporting Tachyta.

Thanks Peter, my knowledge of beetle anatomy is just the pits! But I assummed the prosternum would have stopped apically well shy of the eyes, thus making this what from Dillon2 ref. looks to be called the Gula and further forward the submentum.

But in any case, I just posted a ventral image of what I believe is a species of Paratachys, which if I have things right, should have the "pits" you reference (as not being on Tachyta, but other memebers of the tribe). But if I've misled us again, please correct me.

Thanks,

are very familiar to me with regards to carabids and I suspect these ventral forebody structures carry over fairly well to other beetle familes. Tim, with regards to your Tenebriodes, I still think those two pits (arrows) are on an anterior shelf of the prosternum that is hanging over the mentum-submentum. Recall that keys in American Beetles (2001) and Downie & Arnett (1996) say that there is *no* median (midline) pit on submentum of male Tenebroides. In regards to this "male Tenebriodes", I'm not sure if you were intending diagnostic significance to the pair of pits arrowed in your image. Also the "gula" should appear (if present) as a narrow longitudinal strip along midline of ventral head - not shown in your image.

after your previous reply I too went back and looked at the Tenebriodes keys and found, as you say "no median pit" should be present. So like you, I am now puzzled as to why I posted the image of the pair of pits in the first place. I think I should probably just delete it until I can recall a valid reason.

Tenebroi*des is actually a tro*gossitid.

My assumption was logical but wrong!