weird beetle i found today

[ezman]

this beetle has been buzzing round my house the past two nights - wife freaked out so let it outside but took a photo beforehand ...never seen one of these - is it common?

[nutmeg]

Looks like a hawthorn shield bug - pretty common and harmless

[2dogs2000]

I think it is a Hawthorn shield bug.
Someone will come along soon and tell you for sure.
Welcome to the site.
You will find plenty of experts and amateurs willing to help you.

[Dogghound]

It is Acanthosoma haemorrhoidale the hawthorn shieldbug. Not a beetle but a true bug.

[Pudding4brains]

Hmmmm ... just wondering and trying to learn ... you all seem to agree, but what makes this one an Acanthosoma as opposed to an Elasmostethus? What character gives it away?

From the few I've seen myself so far, going by the shoulders I would have guessed Elasmostethus for this one - expecting the ones on Acanthosoma to be more prominent/sharper, but of course there is some variability in that I suppose ... So, what should I look for than?

@ezman: Just to make sure ... Any idea of size? More like say 12mm, or more like around 16(+)mm?

Cheers, Arp

[Pudding4brains]

Originally Posted by Pudding4brains

So, what should I look for than?

Okay, I've looked (again) at a bunch of images on the net that I believe to carry correct IDs ... I had ignored the "green scutellum" character before, because I could find so many Elasmostethus with almost entirely green scutella too, as well as Acanthosoma with some red in it - effectively providing some overlap it seems, but I guess there is something to say for it anyway.

Also, the shoulders on Acanthosoma seem to vary some (as I suspected) - not always as "well developed" as on the ones I've found so far. Is this maybe even some sexual dimorphism maybe? Or not gender-related at all?

Should probably make a collage of some internet images one of these days to see some Acanthosoma with relatively feeble shoulders and reddish scutella side by side with some Elasmostethus with relatively wide shoulders and greenish scutella and then see if I can come up with other morphological differences.... But if you want to "spoil the fun" for me before I find the time - please do not hesitate

Of course, in the field it's not a problem thanks to the clearly different sizes, but for photo ID I clearly need more practice (and need to find more life ones myself)

[Dogghound]

As you say the shoulders are similar although usually more defined in Acanthosoma, also the scutellum is more lobed in Acanthosoma, The colour of the two is quite distinctive also although there is some overlap.

[Pudding4brains]

Originally Posted by Dogghound

also the scutellum is more lobed in Acanthosoma

I think I see what you mean - will try to lookout for that as well.

To me all characters are "subtle" differences, sometimes hard to tell if it's the one or the other, but put together the picture becomes a tad clearer. Will certainly still need more practice though

Thanks for the help!
Arp