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Silvanid Flat Bark Beetle - Cathartosilvanus imbellis

Silvanid Flat Bark Beetle - Cathartosilvanus imbellis
Groton, Middlesex County, Massachusetts, USA
March 16, 2007
Size: 3.5mm
Found under the bark of some firewood, before it went into the fireplace.

Images of this individual: tag all
Silvanid Flat Bark Beetle - Cathartosilvanus imbellis Silvanid Flat Bark Beetle - Cathartosilvanus imbellis Silvanid Flat Bark Beetle - Cathartosilvanus imbellis Silvanid Flat Bark Beetle - Cathartosilvanus imbellis

Moved from Silvanus.

Silvanus sp.
Thanks for the help again Pierre-Marc!

Silvanus sp.
It is a Silvanus sp., but I don't know the species.

tarsi 3 lobed?
If I squint hard, I think I could imagin tarsi #3 lobed beneath, which would mean Silvanoprus angusticollis or possibly Cathartus quadricollis (neither presently pictured in BugGuide). Perhaps Tom can get an extreme close-up of the tarsi with his new super macro lens!

Tarsi #3
Hi Tim, I just want to make sure what to enlarge for help in identification. Is it the foot of the hind leg that shows the underside of it?
I might be able to enlarge one of the shots I already took. If not I might still be able to find the beetle. I put it in a terrarium, and maybe I can find it in there.

any foot will do
I rechecked the key in Downie-Arnett and also looked at Am Beetles, and it seems like any foot will do. I was looking at the right front foot in the photo above, and it looks like the middle tarsi (#3 of 5) could be lobed (doesn't have to be deeply "bi-lobed", as many leaf beetles are - just have "extra" tarsi underneath).

tarsi shot added
I added a close-up of the tarsi, and it looks lobed on the middle segment.

gosh Tom,
sorry to lead us down a path I'm not sure has an end, but I'm not sure I can say with any greater confidence what your beetle is :( I'm beginning to think Pierre-Marc was correct and this is a Silvanus sp. While the taris lobes don't have to be big, I'm not sure I see any lobe on this beetle. And if lobed, from Downie and Arnett I was thinking this would most likely be Cathartus quadricollis. But today I finally found an image here, and that just doesn't seem to fit your beetle as well as some Silvanus sp. Yet the Silvanus sizes stated in Downie and Arnett would rule out anything but S. bidentatus, which has a sharper tooth on the forward pronotum angle and a "ear-tooth" on the head behind each eye.

Bottom line is I'm out of my league and best wait for Pierre-Marc or others to further determine.

Well, personnally, I yet thin
Well, personnally, I yet think that it is a Silvanus sp.. At first, I said this only based on the general and the pronotum shape, and I was waiting your final answer since they are some genera in the "bilobed tarsomeres complexe" that I don't know. Now, by elimination, I think it can't be a member of this complexe since Monamus isn't present in North-Eastern America, Silvanoprus have a constricted pronotal base, Ahaverus are more ovate and the picture of Cathartus quadricollis show that it isn't this species (the only one in this genus). So Silvanus is probably the good answer.

is what it looks like to me.

Silvanid Flat Bark Beetle
That's the right family. Maybe someone can get it down to genus or even species.
Now that spring's almost here, I'll be looking for more beetles. I'll try to post lots of beetles and not too many flies, so that the Coleoptera pages are #1:-)

Ha, ha!
Well, the beetles are way ahead of the fly section. It's the Lepi*doptera that are out front. (beetles' 574 thumbnail pages to Lepi*doptera's 592 at present)

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