Identification of beetles (Coleoptera)

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23.03.2017 18:42, Barnaba

And by what external signs, obvious even in the photo, can you distinguish Curtonotus gebleri from Curtonotus aulica?

Of the external signs, the most significant is the shape of the prsp narrowing in front of the rear corners. It is pronounced in all kurtonotuses, but it is in aulika that it is very sharp and looks like a "serif"due to the fact that the rear corners of the prsp are clearly directed to the sides and are more or less drawn away. In gebleri, the narrowing is smoother and the rear corners of the prsp "look" almost backward, m. b. slightly to the sides, not drawn back.
From other signs: the PRSP in aulica is more transverse, in gebleri it is closer to square; the elithras in aulica, respectively, seem to be more progressive in relation to body length, although I do not know how significant the differences will be if accurately measured in different populations. The color of the upper side of the body of the aulika ranges from reddish to almost black, but there are no bronze (greenish, golden) shades, which are often (but not always) characteristic of the gebleri. The punctuation of the prsp both in front and behind is usually more pronounced in aulika. The spaces of the elithras in the gebleri are rather convex throughout, and in the aulica they are noticeably smoothed out in the posterior part. There is a difference in the armament of the outer edge of the front legs: in aulika, the spines are shorter, more often located, in the amount of 7-11, in gebleri, they are longer, less often located, in the amount of 5-8. But of these latter signs, none by itself can be recommended as diagnostic, but only in combination and taking into account the first.
In this photo imho A. (C.) aulica.

Likes: 3

23.03.2017 23:03, Barnaba

Because C. odoratus is habitually different, it is difficult to confuse it with aeruginosus/spasskianus. There are a lot of His images on the web, compare them. As for C. spasskianus, its PRSP is gently wrinkled and dotted, which makes the disc look smooth and glossy. In aeruginosus, on the contrary, it is roughly wrinkled and dotted, so it is matte with visible dots. This is offhand.

C. odoratus is very variable; some of the described forms closely resemble aeruginosus/spasskianus. In mountain forms, prsp is usually squarer, with a narrower edge, the back of the abdomen is pointed, often a different sculpture of the ribs, and in general they are more graceful and usually smaller, but all this is very "floating", and in lowland forms, these differences, to put it mildly, are often not obvious. As for the "tenderness" or" roughness " of the prsp sculpture in aeruginosus and spasskianus, this is very subjective and, in general, for many populations of these species, I do not see any differences in this trait at all. Plus a noticeable intra-population variability. Examples are below.
Here are some fairly typical nominative C. aeruginosus in appearance: Kemerovo and my from Of Novosibirsk, and here intrapopulation variation in the wrinkling of prsp in the second population (the middle male and the right female are almost smooth, with a shiny disk).
But no less wrinkled C. spasskianus from Irkutsk region. and Tuva. Or am I missing something?
But rather similar to this group of odoratus (unicolored without a border and prsp with a wide edge) from East Sayan, Tuva and Magadan.
Of course, in each case, when comparing any two forms of morphocarabus in this group, it is usually possible to point out some external differences, but each time they are different, and it is often unclear whether they do not overlap even with intra-population variability, not to mention inter-population variability within each form. The question for those who, like you, have seen a lot of this group, was whether it is possible to indicate some specific and at the same time generally understandable external signs with a clear interpretation?

24.03.2017 12:16, Aleksandr Safronov

C. odoratus is very variable; some of the described forms closely resemble aeruginosus/spasskianus. In mountain forms, prsp is usually squarer, with a narrower edge, the back of the abdomen is pointed, often a different sculpture of the ribs, and in general they are more graceful and usually smaller, but all this is very "floating", and in lowland forms, these differences, to put it mildly, are often not obvious. As for the "tenderness" or" roughness " of the prsp sculpture in aeruginosus and spasskianus, this is very subjective and, in general, for many populations of these species, I do not see any differences in this trait at all. Plus a noticeable intra-population variability. Examples are below.
Here are some fairly typical nominative C. aeruginosus in appearance: Kemerovo and my from Of Novosibirsk, and here intrapopulation variation in the wrinkling of prsp in the second population (the middle male and the right female are almost smooth, with a shiny disk).
But no less wrinkled C. spasskianus from Irkutsk region. and Tuva. Or am I missing something?
But rather similar to this group of odoratus (unicolored without a border and prsp with a wide edge) from East Sayan, Tuva and Magadan.
Of course, in each case, when comparing any two forms of morphocarabus in this group, it is usually possible to point out some external differences, but each time they are different, and it is often unclear whether they do not overlap even with intra-population variability, not to mention inter-population variability within each form. The question for those who, like you, have seen a lot of this group, was whether it is possible to indicate some specific and at the same time generally understandable external signs with a clear interpretation?

Ideally, in such complex groups as Morphocarabus, you should blow a bag. In these species, it is remarkably different.
Since we are talking about specific species: in C. odoratus, the antennae of males are simple, and in C. aeruginosus/spasskianus, the antennae of males are 6-9 segments with noticeable callus-like thickenings below. And this, unfortunately, is not visible in the photo. The rest of the signs will be indirect for many – the size, proportions, bulge, shape and sculpture of the prsp and elytra, primary pores, length of the legs, etc.Much becomes visible with experience and viewing serial material.
As for S. aeruginosus and S. spasskianus – I will not argue about the prsp sculpture, I remain in my opinion. The shape of the prsp – in aeruginosus, the rear corners are more drawn down and to the side, the lower edge between the rear corners is not even, but noticeably arched, the side edge of the prsp stands out. In spasskianus – the posterior corners of the prsp are small and obtuse, the lower edge is almost even, and the lateral edge is thin. Again, this is more likely for typical representatives of the species.
And another thing - to identify difficult beetles from photos is generally a thankless task. Especially when people don't bother to specify at least the size and point of fishing. The forum is viewed by many experts, including those on Carabus, but few people respond to the request for definition, because they probably value their reputation. The beetle should be held in your hands, in the photo some signs are not visible or distorted. Therefore, the local definition is more of a direction to dig in.

Likes: 2

24.03.2017 15:23, I.solod

Of the external signs, the most significant is the shape of the prsp narrowing in front of the rear corners. It is pronounced in all kurtonotuses, but it is in aulika that it is very sharp and looks like a "serif"due to the fact that the rear corners of the prsp are clearly directed to the sides and are more or less drawn away. In gebleri, the narrowing is smoother and the rear corners of the prsp "look" almost backward, m. b. slightly to the sides, not drawn back.
From other signs: the PRSP in aulica is more transverse, in gebleri it is closer to square; the elithras in aulica, respectively, seem to be more progressive in relation to body length, although I do not know how significant the differences will be if accurately measured in different populations. The color of the upper side of the body of the aulika ranges from reddish to almost black, but there are no bronze (greenish, golden) shades, which are often (but not always) characteristic of the gebleri. The punctuation of the prsp both in front and behind is usually more pronounced in aulika. The spaces of the elithras in the gebleri are rather convex throughout, and in the aulica they are noticeably smoothed out in the posterior part. There is a difference in the armament of the outer edge of the front legs: in aulika, the spines are shorter, more often located, in the amount of 7-11, in gebleri, they are longer, less often located, in the amount of 5-8. But of these latter signs, none by itself can be recommended as diagnostic, but only in combination and taking into account the first.
In this photo imho A. (C.) aulica.

Still, I still think it's a gebleri. I have seen a lot of them, as well as aulica throughout its range. They are still biotopically distinct. Forest edges and small-leaved forests are gebleri - at least in Belarus, but aulica-open habitats up to the Alps in the highlands of the Caucasus. I'm not going to enter the discussion further .

This post was edited by I. solod - 24.03.2017 15: 30

Pictures:
picture: gebleri.jpg