Trogositidae? - Macrohydnobius simulator

ID confirmed by S.B. Peck: Macrohydnobius simulator female

… v belov, 6 April, 2012 - 3:58pm

Moved tentatively; neat beast.

i would like this confirmed; could you pls key it out? i'll gladly share a pdf copy, just let me know.
Moved from Sogdini.

… v belov, 5 March, 2012 - 11:23am

Macrohydnobius

I tentatively keyed this creature out as M. mathewsii as follows:
1. Protibial spurs enlarged, elongate....2
2. Without a tooth on outer margin of left mandible....3
3'. Elongate protibial spur inserted at or near base. Elytral punctures were all of the same size....4
4. I am not sure how to sex small beetles. Do the genitalia have to be dissected out? If so, how would this be done? I wasn't able to use the key to separate M. matthewsi from M. crestonensis based on male genitalia. So I compared the posterior shapes of sternite 8, ventral view (Figs. 105 and 120). The shape of sternite 8, ventral view, in this specimen is not dished in as in fig. 120, but rather evenly truncate as in fig. 105. Also, the protibial spur resembled Fig. 103 rather than Fig. 118.
Any advice on finding the genitalia?

… Joe, 8 March, 2012 - 11:09pm

sexing-wise, small ones are no different from any other animals

i.e., if the sexes are dimorphic (like in this case), there is no problem; if they aren't, dissection would be the only way --other than observing mating pairs, that is.
please see Peck & Cook (2009) p.37: "outer margin of male protibia prolonged beyond base of tarsi; male protibia with elongate, sinuate apical spur..."
i was unable to see enough leg on your pics, and my tentative ID was based primarily on the mandibular morphology; moreover, M. simulator gals are apparently the darkest ones (couplet 9)

… v belov, 9 March, 2012 - 7:53am

Macrohydnobius protibial spur

I've added two images showing the protibial apical spur. It looks shallowly curved rather than sinuate. Do you think this would be an issue, or would it fall within natural variability for the species?
Thanks
Joe

… Joe, 12 March, 2012 - 12:20am

thanx; the leg confirms it's a female

… v belov, 13 March, 2012 - 8:33am

Thanks

… Joe, 13 March, 2012 - 12:54pm

Sogdini

Sure I'll key it out. Please do send me the pdf copy.

… Joe, 7 March, 2012 - 1:26am

sent; enjoy...

...like i enjoy seeing your fine work on BG!

… v belov, 7 March, 2012 - 1:41am

thanks

I really do appreciate your regard for the photography I submit. Getting involved with BG has motivated me to work on improving my insect photography. Thanks for your kind feedback!

… Joe, 7 March, 2012 - 3:11pm

nice! these are typical winter-active leiodines

use the key in(1)
Moved from ID Request.

… v belov, 5 March, 2012 - 10:02am

Leiodidae

Thanks

… Joe, 5 March, 2012 - 10:43am