Hydrophilidae? - Copelatus glyphicus

Moved

… Tim Moyer, 29 July, 2014 - 8:45pm

Moved

… Graham Montgomery, 19 January, 2009 - 5:59pm

C. distinctus

Keyed from Larson et al. (2001)
Notes: 10 striae on each elytron, length greater than 5.5 mm, range includes TX, AZ, and Mexico

… Tim Loh, 18 January, 2009 - 8:50pm

Copelatus glyphicus

I suppose that this is a rather large Copelatus glyphicus. C. distinctus is a much more elongate species with finer (sometimes broken) elytral striae, and the sutural interstices (between suture and innermost striae) are not markedly widened towards the elytral base (in C. glyphicus the innermost striae are diverging towards the base). The male genitalia of C. glyphicus, as figured by Larson et al. (2000), are very distinctive. The male genitalia of C. distinctus are completely different and have been illustrated by

YOUNG, F.N. (1963). The Nearctic species of Copelatus ERICHSON (Coleoptera: Dytiscidae). Quarterly Journal of Florida Academy of Science 26: 56–77.

… Wolfram Sondermann, 29 July, 2014 - 12:14pm

gradual widening?

so I gather from this and some of our other C. glyphicus that the widening of the sutural interstices is rather gradual, starting around the apical third and barely doubling by the base? I can't really tell on the only other image we have currently placed under C. distinctus, but perhaps the interstices is fairly constant.

Thanks,
Tim

… Tim Moyer, 29 July, 2014 - 8:45pm

yes, it is a gradual widening

Hi Tim,

you did a very well suited description of the item! The other bugguide image placed under C. distinctus is really that species, but you are right, the inner striae are difficult to trace on that photo. The same is true for another photo found on http://insects.oeb.harvard.edu/mcz/Species_record.php?id=15216, under the synonym C. impressicollis. However, once I took a photo from a specimen (no type material) deposited at the Bavarian State Collection in Munich which may be downloaded and integrated in bugguide from my webspace: http://hollimnicinsects.org/DYT.Copelatus-distinctus(cof)HabVar(WoSo-ZSM).jpg. In this specimen and in others which I have seen in the Natural History Museum, London, the inner striae are almost parallel within the basal 2/3 of elytra.

Best regards, Wolfram

… Wolfram Sondermann, 30 July, 2014 - 12:49pm

species page added

… Tim Moyer, 18 January, 2009 - 10:00pm

Thanks

tim and tim.

… Graham Montgomery, 19 January, 2009 - 6:00pm

Thanks

for the genus ID, Tim.

… Graham Montgomery, 4 June, 2007 - 11:18pm

Moved

Moved from Predacious Diving Beetles.

… Graham Montgomery, 4 June, 2007 - 11:18pm

Predacious diving beetle

Family Dytiscidae. Lacks the clubbed antennae of Hydro*philidae.

… Brad Barnd, 2 June, 2007 - 5:49pm

Genus Copelatus

appears to be Genus Copelatus - elytra stria + size make that the only choice I know.

… Tim Moyer, 4 June, 2007 - 9:26pm

Thanks

Thanks for the correction.

… Graham Montgomery, 3 June, 2007 - 9:24am