Help with Elateridae key


I am struggling to key out this Elateridae. I can’t decide on which option to pick.

This is the triplet from Calder 1996 Click beetles: Genera of Australian Elateridae monographs on Australian invertebrate taxonomy vol. 2.

Mesocoxae closed (margin of mesosternal cavity formed by meso- and metasternum only) (fig 6)

Mesocoxae open to mesepimeron only (fig 7)

Mesocoxae open to mesepimeron and mesepisternum (fig 5)

Figures 5, 6 and 7

I can’t makes sense of the figures looking at the specimen. I would appreciate some help.


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The iNat Forum isn’t a place to ask for ID help, so I’ve unlisted this thread. Best to link to the key in a comment or in the description of your observation on iNat and ask for input there. Thanks!

I want help with that exact step though. I don’t want the ID, I want to get that myself. At no point on my post did I request the ID, I just want an explanation for for that step in the key.

iNat forum reaches a wider audience hence why I asked here - not really fair to say I can’t ask here when I am trying to learn specific morphological feature and not just get a simple ID answer.


Sorry about that, thanks for clarifying. Re-listed.


i don’t really know anything about Click Beetles, but the photo below seems to be the one that corresponds with your key:

seems to me like to get a good look at the mesocoxal cavity (CX2), you’d have to take off one of the legs in the bottom half of the photo. then it’s just a matter of seeing if CX2 touches both ES2 and EM2 (=5), neither ES2 nor EM2 (=6), or EM2 but not ES2 (=7).

maybe you might be able to make a determination without taking off a leg, but you’d have to peer underneath one, as they’re blocking the view of the important bits in the photo.

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Thanks tiwane

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I’ll try to get some images at different angles this afternoon. It is a bit difficult as this is a set and dry specimen so I am guessing I would need to rehydrate the specimen and manipulate the legs so they are out of the way.

i’m not sure how diagnostic the other parts of the beetle are, but the HY and S2 from your image looks most like the 5 diagram. ES2 only touches CX2 in 5, and maybe it’s possible to see that without too much manipulation?

I think you are right.

I rehydrated the specimen and unfortunately (although conveniently) the leg came off. I cropped in and drew red lines along the sutures. Thanks for your help!


Looks good. I was reading down the thread thinking “He may need to move or remove a leg.” Sometimes you may have to scrap off some setae to follow sutures. The guidance that I was given was to examine the other side to see if they’re the same, try to muck up just one side, and glue it all back when done (especially if it’s not your specimen) if possible.