Iris003's picture

Black ground beetle

Observed: 15th November 2009 By: Iris003Iris003’s reputation in InvertebratesIris003’s reputation in InvertebratesIris003’s reputation in Invertebrates
DSC 0028
Description:

12mm, found in woodland next to river, in leaf litter.

Identifications
Species interactions

No interactions present.

Comments

dshubble's picture

Ground beetle

Loricera pilicornis is the closest I can get to although as Rob says, it is smaller (6-8mm). If it is this species it would have long bristles on the first few segments of the antennae which it uses to trap the springtails it preys on. I zoomed in on the photo but couldn't tell if these bristles were present or not.

Iris003's picture

Black ground beetle

Dear dshubble, thanks for your identification, but we have looked at the RAW high-res digital photo and can't see any bristles. Also, we have re-measured the container, and it is definitely 12mm from nose to tail!!!

Iris

dshubble's picture

Mystery ground beetle

Hmmm... if it's 12mm long without the antennal bristles, it definitely can't be L. pilicornis. It does look like a Pterostichus species, but the question is which one? P. niger is too large and P. nigrita & P. rhaeticus are all black, including legs & antennae. Hmmm... I'll have a think and if anything springs to mind, I'll be back...

Martin Harvey's picture

ground beetle

I see what you mean about Platynus David, but on my specimens of Platynus the pits or dimples on the wing cases are much less obvious than in this photo, and the pronotum is narrower (narrower than the width of the elytra). The photo still looks like Loricera pilicornis to me - is there any chance that the antennae were included in the 12mm measurement? Otherwise I'm stuck on this one.

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Entomologist and biological recorder

dshubble's picture

Ground beetle

I agree about the general look being Loricera - it's down to size being important! If the observer could confirm whether antennae were included or not, that would be most helpful - if so, then the body size is below 12mm and I'd agree with Loricera, but if not I'm stuck too as Platynus was the only possibility I could come up with for a 12mm or so species.

Iris003's picture

Ground Beetle

Dear Martin + David, we are absolutely sure it's 12mm not including antennae!!!

Iris

dshubble's picture

Mystery beetle

OK, I'm stuck, at least for now - any thoughts Martin?

dshubble's picture

P. macer amongst others?

Some more thoughts - again tentative... First is Pterostichus macer. It has elytral punctures though again the photo in my book shows these to be less distinct than here. It is a flattened species (lives in cracks in clay soil & coastal cliffs and under bark) which I can't determine from the photo.

In Luff's RES Carabidae handbook it is considered to be a more south-eastern (and coastal Welsh) species, but it has been recorded as far north as Yorkshire (northern edge of its range). It's usually scarce and locally distributed, but there could be suitable habitat at the location given. A possible maybe.

P. adstrictus has the deep punctures but is an upland species and has blacker appendages, so that's ruled out. P. oblongopunctatus is similar but in open/dry woodlands and with some reddish-brown leg sections (but not antennae which are black) - also it has four to seven punctures and that doesn't appear to be the case in the photo... so, ruled out too I think.

Brian Cambridgeshire's picture

Damaged Nebria?

The very broad pronotum with very sinuate sides suggests Nebria brevicollis/salina, which also has the red palps, tarsi and tibiae, and reddish antennae, unlike any of the other species mentioned. None of the Nebria have large pits on the elytra, but these seem to be oddly placed, unsymmetrical and not the same shape as the large pits on Pterostichus, for instance. So I'd guess at Nebria with damage to its elytra.