Is this Heterometrus longimanus?

[Arachnopotamus Rex]

I purchased this as a Heterometrus longimanus but it was from a chain pet store so I want to make sure which Heterometrus it is.

Also how do you ventrally sex scorpions? Pretty sure its fully grown so I doubt I'll be getting a molt.

Oh and after buying it, I was told by both the clerk and the internet that H. longimanus is parthenogenic, curious if thats true?

 

[adam james]

This appears to be a juvenile male (male looking operculum, but no chela tooth) Heterometrus silenus. Heterometrus are not parthenogenic.

 

[Arachnopotamus Rex]

This appears to be a juvenile male (male looking operculum, but no chela tooth) Heterometrus silenus. Heterometrus are not parthenogenic.

Is the chela tooth a thing they only grow when they mature? I'm gonna try to get a better picture if I can, that one was pretty blurry.

 

[adam james]

I believe it is only pronounced enough to make a distinction of sex, at adulthood.

 

[Arachnopotamus Rex]

more close ups. for some reason the chela looks less pronounced on camera.

 

[adam james]

These two images are why I feel like this is a male. However i will note in the chela bump pic, the upper tooth looks quite pronounced as well so it could just be the angle of the shot. The image I edited of the operculum looks pointy and male to me, but the IMG_0175.jpg pic of the operculum also makes me hesitant.
Maybe some of the more experienced members will chime in here soon.

 

[Glorfindel]

At last count I believe there are about five or six species being sold as Asian Forest Scorpion.

 

[Tbone192]

I would agree that this is a male. The pectinal teeth are quite long and the operculum appears to lack the "bumps" you see in females. I'd say H silenus, or H petersii but doesn't really look like H longimanus unfortunately. Leaning towards H silenus. If you get a good pic of the carapace it would help with ID.

 

[Arachnopotamus Rex]

At last count I believe there are about five or six species being sold as Asian Forest Scorpion.

Yep, it makes IDing which species it is a bit difficult with how all of them are often mislabeled.
I'd assume the breeders know how to tell them apart though since that genus is readily available pretty much everywhere these days (unless they crossbreed?).

I would agree that this is a male. The pectinal teeth are quite long and the operculum appears to lack the "bumps" you see in females. I'd say H silenus, or H petersii but doesn't really look like H longimanus unfortunately. Leaning towards H silenus. If you get a good pic of the carapace it would help with ID.

I'm fine with whichever species it is, I just like knowing what I have so if I get more I can breed them.
i'll see if I can get a good carapace pic once he leaves his hide again.

These two images are why I feel like this is a male. However i will note in the chela bump pic, the upper tooth looks quite pronounced as well so it could just be the angle of the shot. The image I edited of the operculum looks pointy and male to me, but the IMG_0175.jpg pic of the operculum also makes me hesitant.
Maybe some of the more experienced members will chime in here soon.

So I found this:

Sexing scorpions - how to recognise males and females - Insektenliebe

Scorpions are among the most fascinating and at the same time most mysterious terrarium animals. Many terrarium keepers ask themselves the question at

insektenliebe.com

The pectine size looks female on mine, but the operculum looks male but has a slight point resembling female, also the right chela has a larger and sharper tooth than the left.
The entire chela are about an inch (2.54cm) long for scale.


I'm also leaning male H. silenus though as the most likely verdict.

 

[Tbone192]

Yep, it makes IDing which species it is a bit difficult with how all of them are often mislabeled.
I'd assume the breeders know how to tell them apart though since that genus is readily available pretty much everywhere these days (unless they crossbreed?).



I'm fine with whichever species it is, I just like knowing what I have so if I get more I can breed them.
i'll see if I can get a good carapace pic once he leaves his hide again.


So I found this:

Sexing scorpions - how to recognise males and females - Insektenliebe

Scorpions are among the most fascinating and at the same time most mysterious terrarium animals. Many terrarium keepers ask themselves the question at

insektenliebe.com

The pectine size looks female on mine, but the operculum looks male but has a slight point resembling female, also the right chela has a larger and sharper tooth than the left.
The entire chela are about an inch (2.54cm) long for scale.


I'm also leaning male H. silenus though as the most likely verdict.

Maybe an immature female, just because of how small the details are for proper ID usually a very lucky pic or crazy macro setup is required. The best way is too research and find out how to ID them and their genders separately. I have a Javanimetrus/ex Heterometrus cyaneus and that took me a while to ID. Thankfully there are plenty of experienced keepers on here. I almost forgot, there was a revision a while back and almost all hobby H petersii were reclassified as H silenus. Apparently true H petersii are fairly hard to come by.

 

[Arachnopotamus Rex]

Maybe an immature female, just because of how small the details are for proper ID usually a very lucky pic or crazy macro setup is required. The best way is too research and find out how to ID them and their genders separately. I have a Javanimetrus/ex Heterometrus cyaneus and that took me a while to ID. Thankfully there are plenty of experienced keepers on here. I almost forgot, there was a revision a while back and almost all hobby H petersii were reclassified as H silenus. Apparently true H petersii are fairly hard to come by.

Possible, though if this is a juvie its going to get BIG
That bit about silenus vs petersii certainly explains why those 2 species looked identical in the images I found of them, but that also probably means it is H. silenus since it was just from a pet store that gets them every week, though now I'm wondering if the ones they get weekly are all the same especies, or various different Heterometrus/Gigantometrus/Javanimetrus?
I might get some more and compare them when they restock.
Now its just a matter of trying to get a clear carapace photo, its proving quite difficult, but its out right now so I'm currently attempting it.

 

[Arachnopotamus Rex]

I would agree that this is a male. The pectinal teeth are quite long and the operculum appears to lack the "bumps" you see in females. I'd say H silenus, or H petersii but doesn't really look like H longimanus unfortunately. Leaning towards H silenus. If you get a good pic of the carapace it would help with ID.

Will this work?

 

[Arachnopotamus Rex]

According to the store's question and answer team, it is H. silenus, and is just mislabeled as H. Longimanus in that store location because it was a prior stocked scorpion.

 

[The Snark]

So I found this:
https://insektenliebe.com/en/sexing-scorpions-how-to-recognise-males-and-females/

Best web page I've seen so far.

I've been hopelessly confused trying to sex scorps. Bored, I got inspired for a brief moment and installed the facial characteristics matching program some police labs used. I fed it all the OP pectine/operculum images and the images off that web page. Multiple pass matching produced >90% probability female.

Of more interest to me was how that program operates. Much more complex than people realize. It first required identifier parameters, mostly perimeters, and kept asking for more until I was thinking the program crashed. Then it created a series of images, black and white, grayscale, turned 90 degrees for all four directions, contrast incrementally reduced to zero and increased to 100%, made stick like figures, various outlines, overlayed geometric frames and some other weird stuff. An amazing amount of data extracted as it munched away on my rather slow comp for about 15 minutes,
If people can get their hands on one of those programs it's fascinating to watch it at work. Mine was a retired older version from the San Francisco crime lab. Proprietary, 22 GB, written to run on Windows 7 but Win 10 seems to have improved it's performance. No doubt now days the facial recognition software has been exponentially improved.

 

[Tbone192]

Glad it's been figured out, it is always nice to know what you are keeping. I'm keeping my eyes peeled for more J cyaneus and a G swammerdami would be cool but I doubt I'll get that lucky.

 

[Arachnopotamus Rex]

Best web page I've seen so far.

I've been hopelessly confused trying to sex scorps. Bored, I got inspired for a brief moment and installed the facial characteristics matching program some police labs used. I fed it all the OP pectine/operculum images and the images off that web page. Multiple pass matching produced >90% probability female.

Of more interest to me was how that program operates. Much more complex than people realize. It first required identifier parameters, mostly perimeters, and kept asking for more until I was thinking the program crashed. Then it created a series of images, black and white, grayscale, turned 90 degrees for all four directions, contrast incrementally reduced to zero and increased to 100%, made stick like figures, various outlines, overlayed geometric frames and some other weird stuff. An amazing amount of data extracted as it munched away on my rather slow comp for about 15 minutes,
If people can get their hands on one of those programs it's fascinating to watch it at work. Mine was a retired older version from the San Francisco crime lab. Proprietary, 22 GB, written to run on Windows 7 but Win 10 seems to have improved it's performance. No doubt now days the facial recognition software has been exponentially improved.

Thats very interesting, whats the software name?

Glad it's been figured out, it is always nice to know what you are keeping. I'm keeping my eyes peeled for more J cyaneus and a G swammerdami would be cool but I doubt I'll get that lucky.

It is, and yeah those are far harder to find unfortunately, they are on my (very extensive) wishlist as well.
I really want a large parthenogenic scorpion that has mild venom (assuming one exists) Liocheles australasiae is on my wishlist as it meets at least some of that criteria (is parthenogenic and has mild venom).

Btw did the carapce pic I posted fit the H. silenus match?

 

[The Snark]

Thats very interesting, whats the software name?

I can't disclose the name since I'm not supposed to have it. But something quite similar can be found here: Ideally you want a source code in a language you are familiar with and a robust extendable library. I suggest avoiding real time operations as it's unnecessary bloatware for use with video and live action.

Top 10 Open Source Facial Recognition libraries and tools - Twine Blog

A look at 10 of the top open-source libraries and tools for adding real-time facial recognition capabilities to your AI model.

www.twine.net

 

[MorbidArachnid]

I'd say Heterometrus silenus or laoticus female. Male operculum looks a bit more triangular and doesn't have the two bumps on either side of the split on the posterior margin.

Male on the left, female Heterometrus spinifer on the right. Operculum should look basically the same as in silenus. Heterometrus petersii was mislabeled and was widely considered a synonym of Heterometrus silenus, it's actually a cryptic species of Heterometrus spinifer and doesn't look like silenus at all. It's basically morphologically indistinguishable from Heterometrus spinifer but genetic testing preserved it as a separate species.

https://mds.marshall.edu/euscorpius/vol2023/iss373/1/

This paper has some good notes on the H. petersii misidentification as well as talks about how to distinguish Heterometrus silenus from Heterometrus laoticus. I don't really have anything concrete to tell you why I don't just say it's Heterometrus silenus for sure, just that I'm getting a little bit of a gut feeling from it. Pics can't be conclusively stated either way, would need to see the granulation on the cheeks.



If she has these distinct freckle like granules on the cheeks of the prosoma then she's a Heterometrus silenus. If not, she's a Heterometrus laoticus.

 

[Arachnopotamus Rex]

I'd say Heterometrus silenus or laoticus female. Male operculum looks a bit more triangular and doesn't have the two bumps on either side of the split on the posterior margin.
View attachment 485279 View attachment 485280
Male on the left, female Heterometrus spinifer on the right. Operculum should look basically the same as in silenus. Heterometrus petersii was mislabeled and was widely considered a synonym of Heterometrus silenus, it's actually a cryptic species of Heterometrus spinifer and doesn't look like silenus at all. It's basically morphologically indistinguishable from Heterometrus spinifer but genetic testing preserved it as a separate species.

https://mds.marshall.edu/euscorpius/vol2023/iss373/1/

This paper has some good notes on the H. petersii misidentification as well as talks about how to distinguish Heterometrus silenus from Heterometrus laoticus. I don't really have anything concrete to tell you why I don't just say it's Heterometrus silenus for sure, just that I'm getting a little bit of a gut feeling from it. Pics can't be conclusively stated either way, would need to see the granulation on the cheeks.

View attachment 485281 View attachment 485282

If she has these distinct freckle like granules on the cheeks of the prosoma then she's a Heterometrus silenus. If not, she's a Heterometrus laoticus.

so its incredibly difficult to see them on this image because i still cant get the hang of taking clear photos, and it seems there are less of them, but they are present.

 

[MorbidArachnid]

so its incredibly difficult to see them on this image because i still cant get the hang of taking clear photos, and it seems there are less of them, but they are present.

Yea there's some differences between female and male granulation, but that's a Heterometrus silenus.