It Gromphadorhina portentosa ' black ' or Gromphadorhina grandidieri ' black '?

I would think G. grandidieri because of the notched pronotum and the wide angle of the "horns". Hopefully someone more knowlegable than I will cache in their idea.

 
Posting a picture of him by a ruler would help. G. grandidieri are usually bigger than portentosa.

 
Gromphadorhina portentosa coloration is highly variable, there's no physical character that would differentiate a black G.portentosa from a yellow or orange one and both can be produced by the same female. It would be like saying orange and black goldfish are different species. The real problem is the various Gromphadorhina so far kept in culture (and so-called princisia) all have the same male genitalia and readily interbreed despite some visible differences in the shape of the pronotum and those differences are almost as variable as the coloration.

 
Orin McMonigle said:
Gromphadorhina portentosa coloration is highly variable, there's no physical character that would differentiate a black G.portentosa from a yellow or orange one and both can be produced by the same female. It would be like saying orange and black goldfish are different species. The real problem is the various Gromphadorhina so far kept in culture (and so-called princisia) all have the same male genitalia and readily interbreed despite some visible differences in the shape of the pronotum and those differences are almost as variable as the coloration.
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Orin, just to be clear it was systematic not a taxonomic error? I mean it’s not weather it is G. portentosa or G. grandidieri but the fact that it’s a species complex by your definition (and common species concepts) within G. portentosa…correct?

 
It's both, the specimen pictured is G.portentosa and whoever originally came up with the name likely gave it the wrong name since they didn't think it would sell or trade as readily under the correct name. Additionally, the whole Gromphadorhina genus (plus the "princisia") is messed up since they have the same male genitalia, interbreed readily and were described only using pronotum structure which varies.

 
If grandidieri and portentosa are the same species, why are the "grandidieri" all so huge? Is it just a big strain that they've been marketing as a different species?

 
Orin McMonigle said:
It's both, the specimen pictured is G.portentosa and whoever originally came up with the name likely gave it the wrong name since they didn't think it would sell or trade as readily under the correct name. Additionally, the whole Gromphadorhina genus (plus the "princisia") is messed up since they have the same male genitalia, interbreed readily and were described only using pronotum structure which varies.
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Very interesting...you may have given me a project for my Masters! I wonder if Beccaloni is still working on that still? Fun stuff.

 
Yes, it is a lot of mess.

But how to understand?

All means Portentosa in culture these are hybrids?

Pronotum Gromphadorhina portentosa 'black':







 
That last specimen is nice looking-

As Orin said, all Gromphadorhina are completely messed up. There are different varieties but they are still incorrectly described and are still all G. portentosa by definition. I keep all my "varieties" seperate very carefully to preserve these variances until someday they are reclassified together or seperately, somehow.

Afterthought: I wonder if they are G.portentosa that are geographically varied by micro-climate? Or do any two varieties share a range in nature?

Hmmmmm...... :blink:

 
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