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Sap Beetle on Carrion - Omosita discoidea

Sap Beetle on Carrion - Omosita discoidea
Near Ruraldale, Upshur County, West Virginia, USA
March 24, 2005
Size: 3.3 mm
Tiny beetle (just over 3 mm) found on a deer carcass. Based on the beetle's shape and the ball-ends on the antennae, I came up with an ID of Nitidulidae. Corrections appreciated, or if anyone can help with genus or species that would be great too.

Moved from Omosita.

vote for O. discoidea

forget about what is written in keys sometimes . . .
. . . and believe me: It is Omosita discoidea, colour pattern is distinctive for this species!

regards, Boris

That makes it two to one for O. discoidea,
and the one, Andrew Cline, didn't say it *wasn't* discoidea.

Omosita discoidea
is suggested for this image by Nitidulid specialist Dr. Sci. Alexander G. Kirejtshuk, Laboratory of Insect Systematics, Zoological Institute, Russian Academy of Sciences after his perusal of the family on bugguide. "Although," he says, "O. inversa can be very similar."

Omosita colon and O. discoidea are the only Nearctic species, according to While that might then suggest this is O. discoidea, on the other hand if our other expert Dr. Cline left it as Omosita sp. even though there are only two Nearctic species, I would hestitate to pin a specific name on it without knowing more.


Stephen Cresswell
Buckhannon, WV

Leaning towards O. colon
Working closely with Downie & Arnett, I am leaning towards an ID of O. colon for this beetle.

Overall it seems to match their text description of O. colon better than it matches their write-up of O. discoidea.

Also, in one test that can be quantified, it has the pronotum about twice as wide as long, a trait of O. colon. According to Downie & Arnett, the width to length ratio of O. discoidea is more like 1.6 to 1, and that doesn't match the beetle in my photo.

On the other hand, the difference in markings with the photos already identified as O. colon on BugGuide, and the somewhat different pronotum width to length ratio in those photos, does suggest we have more than one species represented here.


Stephen Cresswell
Buckhannon, WV

Cline should see this
unless he unsubscribed as he went. I will did forward him Kirejtshuk's message about it however.

Omosita sp.
Omosita sp.

Andrew, many thanks for your IDs of this and other Nitidulidae on BugGuide. We really appreciate it!


Stephen Cresswell
Buckhannon, WV

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