Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada
Photo#275399
You shine - Bembidion confusum

You shine - Bembidion confusum
Medford, (~25 miles east of Philadelphia, PA) Burlington County, New Jersey, USA
April 25, 2009
Size: 5.9mm
Bembidon sp.?

came to UV light

Images of this individual: tag all
You shine - Bembidion confusum You shine - Bembidion confusum

Moved
Moved from Ground Beetles.

Bembidion - subgenus Odontium
= B. coxendix species group sensu Lindroth 1963 in which image appears to be at or near B. confusum based in part on red-brown coloration of elytra. If B. confusum, then elytra should typically also have greenish punctate striae against dominant red-brown color of intervals. I'm not sure I see green striae in this image. Incidentally, clear and perpendicular views are quite nice.

 
Thanks Peter,
I examined this beetle under the scope using two different lighting frequencies and types (spot and diffused) from various angles, and the punctate striae consistantly had a strong greenish color, compared to the red-brown intervals (I believe you can also see this coloring in my images, at least for the more lateral punctures). The only strange thing is that without magnification the beetle seems largely shiny light brass with hints of green. I never would have guessed the intervals were so dark without looking under the scope (or the images).

Unless you object, I'll move this one to B. confusum.

Thanks again

 
Move to B. confusum
makes sense now that you confirmed green striae under magnification. Thanks. Here is further evidence of how microscopy delivers so much more visual information (even color) that can not be appreciated on just distant habitus images. BugGuide photo sumbmitters who also have personal stereo-microscopes (a small minority) have great advantages in narrowing in on the correct species identification.

 
I had overlooked editor's option to maximally enlarge
your images for closer examination. I rediscovered this option just now. That helped me visualize the green tinge along some of the lateral striae. It is really nice that the high resolution carries over to your expanded images. The detail is great. I must admit that I had missed doing enlargements for your recent images which I commented on. I notice Tom Murray has nice images too but I can't expand his. Why the difference? Thanks.

 
possibly image size reduction edit
Tom has a much better camera set-up than I do, so I suspect he choses to reduce the pixel count of his images during his final editing phase. Regardless, smaller image sizes take up less BugGuide disk space, and some probably frown on my large size posts as "disk-hogs". But for good images such as this one (well-cropped, good depth of field, and probably most important - new or almost new to BG), I feel it justifies the larger size to aid in the examinations like you perform.

 
Disk space
BugGuide has plenty of disk space. The mythical BugGuide 2.0 will include the ability to mark certain images as "best examples of".

 
The "best examples of"
tag given to certain images is great. Hopefully those images will either be isolated or at least prominently displayed against the rest.

 
My hopeful envision of the ideal BugGuide Image Library
for at least the Carabidae is that there be only one small set of 'best' images (perpedicular dorsal/ventral habitus + pronotum closeup) designated as the comparative "morphotype" for that particular species. That set of images which should appear first in any search, should also by maximally expandable like yours Tim. All other image submissions for that species should probably be in the background and be of the usual lesser pixel count in order to conserve on disk memory. I assume there are photographers like Tom Murray who keep the high pixel version at home but submit only the lower pixel version. That means if a submitted low pixel image is later deemed by overseer(s) to be the new "morphotype", then the owner of that image could resubmit same at (cropped) higher pixel count. Obviously, the first and only images (regardless of quality) of a species new to BugGuide should automatically fall into the morphotype. There remain questions of what steps are taken and by who to replace previous morphotype sets with 'better' ones. What on the surface appears to be a 'contest' for coveted morphotype status, in the long run will benefit future BugGuiders attemting to compare difficult and closely related species. I welcome additional suggestions.