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Photo#90033
Bidessonotus inconspicuous (LeConte) - Bidessonotus

Bidessonotus inconspicuous (LeConte) - Bidessonotus
Medford, (~15 miles east of Philadelphia, PA) Burlington County, New Jersey, USA
July 11, 2006
Size: ~2.3mm
keyed using Downie and Arnett, and matches description and photo here Great Smoky Mountains Biodiversity Inventory Corrections welcome! Difficult to see in this photo, but there's a line of punctures with seta running between the eyes on this beetle.

This makes the eleventh Dytiscidae species found during 2 nights in July with a BioQuip UV light trap on my porch. And the nearest permanent stream or pond is over 0.5 mile away. It's been great fun!

Images of this individual: tag all
Bidessonotus inconspicuous (LeConte) - Bidessonotus Bidessonotus inconspicuous (LeConte) - Bidessonotus Bidessonotus inconspicuous (LeConte) - Bidessonotus

Moved

identification
This specimen appears to be a B. longovalis because of the longer elytral plicae (little grooves at the base of the elytra) BUT ... identification of Bidessonotus usually requires dissection of male genitalia; thus positive ID of this critter would require pulling out its genitalia (which are distinctive - see my 1996 FL water beetle guide)

Downie and Arnette is NOT a suitable reference for identification of dytiscids ...

 
Thanks Dr. Epler,
I'll move it back to the genus page. I did check Larson's ref. and of course the ID requires dissection as you stated. But Laron also lists B. longovalis as from "Georga, Florida, and Alabama". So I thought perhaps location might be enough in this case?

Regarding Dytiscid references, I have found your 1996 FL guide very useful, even up here in south Jersey. And some time ago I added it to the family Dytiscid info page here at BugGuide, and directed others to it in various comments thoroughout the family posts. But I'm sure you'll find no shortage of ID errors on my part.

Thanks again for your time,
Tim

B. inconspicuus
Moved from Predacious Diving Beetles to new species page.

Apparently a male; females have a preapical "tooth" on the outer margin of each elytron. B. pulicarius is virtually identical but has a maximum length of 2.0 mm, so I'm assuming that your measurement is accurate to within two-tenths of a millimetre. In males that are 2.0 mm or less, dissection of genitalia would be necessary to ID to species, according to info on the Guide page.

 
Thanks Robin
I posted another image which is not focused very well, but good enough to determine size of at least something over 2mm.

B. inconspicuus in the only sp. Downie and Arnett list for the genus, so I assummed there weren't any other possibilities. If there's anything else I should check, please let me know.

Happy New Year,
Tim