[ID] Malachiidae; Axinotarsus sp.

[Jason Green]

Afternoon all,

I've just been giving some time to my collection today, identifying a few specimens. The Malachiid depicted below I had down as A. marginalis. I don't have a key to these so viewed a few other websites which all showed darkish antennae. Mine are yellowish!

10/07/2011

Views: Micro-staged+set dorsally, extent of yellowish antennae and tips of elytra.
Found on my clothing, by a Buddleia bush growing in a brownfield environment. Length: c3mm

Looking at Kerbtier.de I find it matches well with my specimen when examined through the microscope. This includes the slightly concave elytral apice, the dark first antennal segment and the others being yellowish bar dark discs on 2-3 and the yellowish second-half to the mid-legs.

My only issue with the determination is the fact in the UK this species is classified as RDB1...

I can check any important points. Help please!

Take care,

Jason

[Klaas Reißmann]

Hi Jason,

make it a pulicarius. You found the right characters.

Regards
Klaas

[Jason Green]

Thanks Klaas! So these points are those used in the key to Central European Cleroidea?

[Klaas Reißmann]

Hi Jason,

there are three species of Axinotarsus in Centraleurope. I don't know how many can be found in the UK, but if it is three, it will be the same species.

No.1, Axinotarsus ruficollis, you can identify very easily by looking at the pronotum. It is the only one of these three species, which pronotum is coloured reddish all over.

The red colour can be found at the other two species, too, but only at the left and right border of the pronotum, but only in a broad, red band, broken by a broad black band. This band is typically formed, but the differences are not much. Antennae in A. marginalis almost black, in A. pulicarius the first two limbs more or less black (the first more, the second less) coloured, the others almost yellow coloured. Front and middle tibia in A. marginalis black, in A. pulicarius upper half black, lower half yellow.

Have even a look at Christoph's pages: Fotoübersicht der Malachiidae (Zipfelkäfer) Deutschlands - kerbtier.de

Out of the UK you have to be a bit careful, because of genus Cyrtosus, which is very similar to Axinotarsus. I guess it does not occure in the UK, but if, you have to be careful, too.

The european keys are a bit different. They tell about the size of the limbs of the antennae (A. marginalis double as long as wide, A. pulicarius a little longer than wide), but this character is wrong in my mind. They also tell about the colour of the legs, which is right. They do not tell anything about the colour of the pronotum and the colour of the antennae.

Regards
Klaas

P.S.: Sometimes I wish you could speak German. I would have a lot of literature for you.

[Jason Green]

Thanks. What features characterises Axinotarsus and Cyrtosus? I don't have time to check my specimen now, but will do after work.

This will be a good British record; we don't seem to have Cyrtosus, and the points you list match my specimen exactly.

[Klaas Reißmann]

Hi Jason,

Cyrtosus is different in its hairy Elytra and the different habitus of its pronotum. You can see, when you know about these characters, while beeing outside. It even seems to be more colourful, red, partly intense yellow, black and the Elytra bluish. The head is very wide, the temple not rounded but straight and it has got preceding eyes that make the head more brought than the pronotum. Take a look for it on Christoph's pages.

If your found is a good one for UK, you earn my compliment and my congratulations for this. Great thing and good job. That's the fun in surching beetles (or other insects ).

Regards
Klaas

P.S.: Because of your questions for Axinotarsus I wrote a key to the genus Axinotarsus and Anthocomus. It is not useable yet, but Christoph gave me the ok for the first key, will be looking for the second, than we will translate it into English and after we did all this, we have to look for the right photos to show details. After all this it can be found on Christoph's pages and I do hope we get it managed within October.

[Jason Green]

Thanks Klaas! Yes, it's an RDB1 so one of the rarest categories and the second rarest I've ever recorded.

The thing is, the landowner is concerned about a development on the site neighbouring it. There's a lo of local opposition so I'll enter into the fray with this, see what I can do.

[Jason Green]

I've just got the specimen under the microscope. The first antennal segment is almost entirely black. The second has a 'black splodge' on the dorsal surface but the rest is a nice clear, brightish orange. The third and fourth segments bare a thin black line along the centre of their dorsal surfaces but the rest is a clear orange visible from directly above. All other segments are a fresh orange except the more elongate terminal segment that is tipped black. Each segment a little longer than wide, thickish and only the last one or two are more comparatively elongate.

The fore-tarsi are four-segmented. The first segment is orange, the inflated second is the same but black-tipped and the last two are dark/blackish.

[Klaas Reißmann]

Hi Jason,

is this a question to verify my ID by description instead of the photo? Or is it something else you want to tell or ask or some kind of insecurity, because of the rare found?

How ever, the beetle seen in the photo in this thread surely is Axinotarsus pulicarius, you made a great found (RDB1 - I'm always glad to find beetles like this) and nothing can make it cheaper than that.

Regards
Klaas

Edit: The only thing I can do more for you, is taking a look at the beetle itself and send it back, including an ID-label with "t. K. Reißmann", or if you prefer "vid. K.Reißmann". But therefor I need to see the beetle.

[Jason Green]

Yes, just a clarification of the key points as viewed down the microscope rather than just the photo. Because, comparing my image above to what I see of it under the microscope, the fore and mid tibiae aren't as yellow as they appear here. So, I thought I'd just say what I could see through the microscope to see if this still fits with a typical description of pulicarius. Particularly the colour of the first two antennal segments+tarsi.

Yes, I'll think about sending - I'm just a little busy with work at the moment.