Onthophilus sp - Onthophilus

Size

… Jim McClarin, 31 December, 2008 - 7:41pm

...

This is either O. nodatus or O. pluricostatus. According to the key from Helava's revision (1978), O. pluricostatus has metasternum with a strongly impressed, longitudinal, broad channel; triangular, minutely punctured discal areas (metasternum) elevated and irregularly oval. O. nodatus has metasternum without a strongly impressed, longitudinal, broad channel; triangular, minutely punctured discal areas (metasternum) fused or not elevated.

This specimen does not seem to have a strongly impressed, longitudinal, broad channel. I would lean toward O. nodatus, but wouldn't feel confident without comparing it with reference material under a scope.

BTW - the specimen of O. nodatus I posted was given to me by you when I visited FL back in 2002. Nice to see ya on BugGuide. And I hope to see more histerids posted from you.

… Jeff Gruber, 31 December, 2008 - 6:01pm

different angle/lighting?

Would a different angle or lighting of the metasternum help? If not, do you think that these should be frassed because of not showing species-level characters, or..?

After looking at the links for the two spp you mentioned, I think that it looks more like nodatus. It may not be diagnostic, but the lateral edges of the pronotum look angled on your nodatus pic and this one, but rounded more on the other sp. Also, the two median ridges on the pronotum seem to go a bit farther posteriorly on your nodatus and my specimen instead of "petering out" sooner. Other than that, the gestalt is more nodatus-like, at least compared to your pictures. Of course, this all may not matter at all as far as a positive ID.

I don't usually do much with histerids, but having a guru interested in looking at them makes me want to do more. Thanks.

… David Almquist, 31 December, 2008 - 10:00pm

different angle

Could you lay the specimen on its dorsum, like the 3rd and 4th pics. Then take a shot pointed straight ahead and level with the substrate toward the pygidium. This might show whether it has a depressed broad channel or not.

Thanks.

… Jeff Gruber, 4 January, 2009 - 5:29pm

nice --

i'm fond of these guys; hopefully, Jeff Gruber will be able to tell the sp., the pix are good

… v belov, 31 December, 2008 - 10:32am