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 Borneo: Erythrus group viridipennis
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Andre
Member Rosenbergia

Germany
1020 Posts

Posted - 10/03/2013 :  01:09:37  Show Profile  Email Poster  Reply with Quote

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Borneo, Trus Madi,
Female, 17 mm.

dryobius
Member Rosenbergia

USA
1263 Posts

Posted - 10/03/2013 :  04:45:51  Show Profile  Email Poster  Reply with Quote
There are 3 described, similar green Erythrus in Northern Borneo.
It is not possible to identify from your photo:
E. viridipennis Gahan, E. crinitoguttatus Holz., & E. gilvellus Holz.

Carefully read Holzschuh's diagnosis and good luck. E. gilvellus is the least common. One of Holzschuh's species has a small indistinct area of pubescence on the vental area. The punctation of the elytra will also help. If you don't have all 3 species, then it is somewhat difficult to see the differences.

I don't know of any undescribed green species, but there are many undescribed red and black ones remaining.

With a highly magnified image of the base of the elytra, I could give a better answer.
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Andre
Member Rosenbergia

Germany
1020 Posts

Posted - 10/03/2013 :  15:01:57  Show Profile  Email Poster  Reply with Quote
Hallo Dan, here a picture from Pronotum/elytra.


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dryobius
Member Rosenbergia

USA
1263 Posts

Posted - 11/03/2013 :  06:21:21  Show Profile  Email Poster  Reply with Quote
This is E. viridipennis Gahan.
But the differences between the 3 green Erythrus are easier to see if you had an even greater magnification of the punctation on the elytra.
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Andre
Member Rosenbergia

Germany
1020 Posts

Posted - 13/03/2013 :  18:58:57  Show Profile  Email Poster  Reply with Quote
Hallo Dan, a greater magnification for this is not possible with my equipment.[


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Francesco
Forum Admin

Luxembourg
7762 Posts

Posted - 07/04/2013 :  12:17:32  Show Profile  Email Poster  Visit Francesco's Homepage  Reply with Quote
In order to separate the three green Erythrus-species, you should use this simple key:

1. Procoxae yellow... gilvellus
-. Procoxae black.... 2


Erythrus gilvellus

2. Pronotum (red) unicolor... viridipennis
-. Pronotum with two minutes black spots... crinitoguttatus


Erythrus viridipennis/crinitoguttatus
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Andre
Member Rosenbergia

Germany
1020 Posts

Posted - 07/04/2013 :  12:58:07  Show Profile  Email Poster  Reply with Quote
Hallo Francesco, Thank you for this Key.
The procoxa by my Spec. is black. Than is it E. viridipennis. Top!
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dryobius
Member Rosenbergia

USA
1263 Posts

Posted - 07/04/2013 :  20:24:12  Show Profile  Email Poster  Reply with Quote
The black spots on the pronotum are only present on a few of my paratypes of E. crinitoguttatus.
You can not rely on that simple character.
Does Holzschuh's description say that "all" crinitoguttatus have black spots on the pronotum?
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Francesco
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Luxembourg
7762 Posts

Posted - 08/04/2013 :  19:01:12  Show Profile  Email Poster  Visit Francesco's Homepage  Reply with Quote

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This is Holzschuh's original description of E. crinitoguttatus.
Actually, the missing of points is a character differentiating E. viridipennis (as usual, Holzuschuh's differential diagnoses are inverted: he differentiate the old species instead to differentiate the new one). But some E. crinitoguttatus could miss the black points, you are right.
However, nothing is written about the elytral puncturing.

The true character is the presence of a spot of yellowish or brownish hairs at both sides of the posterior margin of the metasternum.
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Francesco
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Luxembourg
7762 Posts

Posted - 08/04/2013 :  19:05:25  Show Profile  Email Poster  Visit Francesco's Homepage  Reply with Quote

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In order to complete the topic, this is a pair of Erythrus crinitoguttatus Holzschuh, 2006.

Borneo, Trus Madi, V.2011
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Francesco
Forum Admin

Luxembourg
7762 Posts

Posted - 08/04/2013 :  19:10:08  Show Profile  Email Poster  Visit Francesco's Homepage  Reply with Quote

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And this Erythrus gilvellus Holzschuh, 2006
Same data.
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dryobius
Member Rosenbergia

USA
1263 Posts

Posted - 08/04/2013 :  22:40:25  Show Profile  Email Poster  Reply with Quote
In my series of green Erythrus from Sabah, I find specimens of all three species with identically colored pronotum and elytra. Unfortunately, you can not separate any of them by a quick examination.

The "true character" which you mentioned: the patch of pubescence on the posterior margin of the metasternum, is a VERY SMALL patch !! It is there to see, but it is also easy to miss.

But, even Holzschuh told me that his first clue that there was more than one species was when he noticed the differences in the microsculpture of the elytra. I presume he was using about 20x magnification.
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cerambyphil
Member Purpuricenus

France
413 Posts

Posted - 27/03/2017 :  10:45:47  Show Profile  Email Poster  Reply with Quote
Dan,
Do you know if a new green species of Erythrus was described since 2013?
I've the feeling of having 4 different species in my collection.
  • Erythrus viridipennis with entire red pronotum and reticulated elytral surface;
  • Erythrus crinitoguttatus with a pronotal black spot at the external side of the procoxae, one hairy yellowish/brownisk spot one each side of the median line of the base of the metasternum and a coarsely punctuated elytra;
  • Erythrus gilvellus with partially yellow forecoxae, black pronotal area at the external side of the procoxae and reticulated elytral surface;
  • Erythrus nov. sp.? with anterior coxae yellow on its front side, black pronotal area on the sides and at the rear of the procoxae and coarsely elytral puncture.

This species is located in West Kalimantan, Mt Bawang and looks like crinitoguttatus shape.
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Gontran
Member Purpuricenus

Canada
278 Posts

Posted - 27/03/2017 :  15:41:19  Show Profile  Email Poster  Reply with Quote
Thank you all. I will certainly use these informations, pictures and key to have a better and closer look at those green Erythrus. Even with specimens of E. viridipennis determined by Holzschuh and one paratype of the other two species, it is difficult to separate them. All my crinitoguttatus have those two black spots. But I am not so sure now about all the other determinations. Many have a (?).

Gontran
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dryobius
Member Rosenbergia

USA
1263 Posts

Posted - 27/03/2017 :  16:49:05  Show Profile  Email Poster  Reply with Quote
There has not been any new "green" Erthrus described. For me, it is very possible that you have a new species.

I have one specimen from Sabah that looks like a hybrid between a green and red species. It has a most unusual color.

I prefer not to speculate on any determinations for this genus, especially from a photograph. Holzschuh still plans on describing more. I have several unique singletons, too. Undoubtedly, there are more waiting to be discovered. Some species are too variable to identify unless you have a series from one place collected on the same date where it is likely that they are the same species.

As with any species that is cryptically colored or a mimic of some foul tasting hemipteran or other poisonous insect... there tends to be more variability than normal.
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cerambyphil
Member Purpuricenus

France
413 Posts

Posted - 27/03/2017 :  20:23:27  Show Profile  Email Poster  Reply with Quote
Thank you Dan for your answer.
Indeed, I have a small set of 6 insects with the same data of this indeterminate species.
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