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Photo#225077
dytiscid larva? natural light - Cybister

dytiscid larva? natural light - Cybister
World Birding Center HQ at Bentsen-Rio Grande Valley State Park, Hidalgo County, Texas, USA
April 29, 2007
Dip-netted this critter out of our resaca (oxbow lake). Have captured adult Hydrophilids here but no Dytiscids yet, but this sure looks to me like a Dytiscid larva...

Images of this individual: tag all
dytiscid larva? natural light - Cybister dytiscid larva? indoors - Cybister dytiscid larva? close-up of head - Cybister

Moved
Moved from Cybister.

Moved

Cybister sp.
*

 
Muchas gracias
Thanks Tim! What is the distinguishing character of this genus from others? Or is it one of those things that only works after you've keyed out a few hundred of them?

 
diagnostic characters
I figured this out from the larva keys provided in DJ Larson's publication on Neartic Dytiscidae...On top of figuring out the BG images, I am working through my collection from last summer at the same time, learnt alot about this family and still have lots to learn!
This is actually one of the easier larvae to key out even though I've yet to encounter one of these (Cybister are absent in Alberta)- the frontoclypeus is trilobed (visible in the headshot- it's the area enclosed by the mandibles), last 2 abdominal segments with lateral fringes of swimming hairs/setae, and the cerci/urogomphi are very short/vestigial.