Centruroides bicolor?

[ArNT1]

That's a big difference!

 

[Nazgul]

Hi,

here are some more pictures.

Greetings
Alex

 

[Ythier]

Great pictures Alex, as usually
It seems that yours have molted on more time than mine.
Greetings,
Eric

 

[Nazgul]

Hi,

I examined a specimen with a binocular today using the Francke 6 Stockwell book and the Stahnke key. I´d say it´s definately no C. bicolor. Francke & Stockwell are writing in the diagnosis "...Pedipalp chela fixed finger with nine primary rows of denticles..." This species has 8. Furtheron Francke & Stockwell are giving for males 27 - 28 (mode 27) and for females 23 - 28 (mode 26) pectinal teeth. Stahnke is giving 28 - 29 for males and 26 - 28 for females. I counted pectinal teeth of nine of my ten specimens, one had molted too recently. The results are 1 x 27, 3 x 28, 1 x 29, 4 x 30. That means the pectinal tooth count is 27 - 30 (mode 29).

It´s neither C. limbatus, this species has nine rows of denticles as well. Pectinal tooth count and the number of denticle rows could mean it´s C. margaritatus but when I examined the granulation on the chela with a piece of molt the granulation was different from the drawings given for C. margaritatus in the Francke & Stockwell. Of all Centruroides spp from Costa Rica C. margaritatus fits most just because it´s the only species with a similar pectinal tooth count and because of the 8 rows of denticles.

But I don´t think we can be really sure the mother comes from Costa Rica. I will ask Giorgio once again.

My conclusion is that it´s not C. bicolor, nor C. limbatus, nor C. margaritatus nor any other Centruroides spp listed in the Francke & Stockwell. But it´s definately a Centruroides sp .

Greetings
Alex

 

[fusion121]

Hi,

I examined a specimen with a binocular today using the Francke 6 Stockwell book and the Stahnke key. I´d say it´s definately no C. bicolor. Francke & Stockwell are writing in the diagnosis "...Pedipalp chela fixed finger with nine primary rows of denticles..." This species has 8. Furtheron Francke & Stockwell are giving for males 27 - 28 (mode 27) and for females 23 - 28 (mode 26) pectinal teeth. Stahnke is giving 28 - 29 for males and 26 - 28 for females. I counted pectinal teeth of nine of my ten specimens, one had molted too recently. The results are 1 x 27, 3 x 28, 1 x 29, 4 x 30. That means the pectinal tooth count is 27 - 30 (mode 29).

It´s neither C. limbatus, this species has nine rows of denticles as well. Pectinal tooth count and the number of denticle rows could mean it´s C. margaritatus but when I examined the granulation on the chela with a piece of molt the granulation was different from the drawings given for C. margaritatus in the Francke & Stockwell. Of all Centruroides spp from Costa Rica C. margaritatus fits most just because it´s the only species with a similar pectinal tooth count and because of the 8 rows of denticles.

But I don´t think we can be really sure the mother comes from Costa Rica. I will ask Giorgio once again.

My conclusion is that it´s not C. bicolor, nor C. limbatus, nor C. margaritatus nor any other Centruroides spp listed in the Francke & Stockwell. But it´s definately a Centruroides sp .

Greetings
Alex

Hi Alex
Very interesting, I'm taking one of these to the British Natural History Museum on Wednesday to see if they can shed some light on the ID of this species as they have all the original description papers there, not to mention many many type specimens.

 

[Nazgul]

Hi,

using the Stahnke key leads to C. margaritatus which I just checked. Maybe it´s really this species. It´s the one that fits most. I´ve never seen a C. margaritatus with that kind of coloration but coloration is a poor character for id´ing scorpions.

Greetings
Alex

 

[fusion121]

I don't unfortunatley have much literature on the Centruroides, however the picture that Giorgio gave of the female adult really doesn't look like C. margaritatus, but perhaps your right and its just a very unusual colour morph.

 

[redhourglass]

Hello fusion, Alex and all.

I for one look forward to a response c/o species determination from the British Natural History Museum.

BTW, Alex...a great post earlier. I wouldn't put to much faith in the Stahnke key. It makes for more madness than clarity in my opinion and it doesn't state fixed or moveable finger with regards to primary granular row counts. I'm going from memory.

An interesting article for reading is :
Frederick Wagner in Descriptions of Centruroides Marx from the Yucatan
Peninsula I don't have the date of publication but is found the literature section of the Catalog. This paper goes into reason respectively with mis diagnoses from previous authors in Centruroides c/o granular row counts. However, it does give a good description of C. marg. and C. gracilis, etc.

It is great to see others go through the flux of Centruroides identification without locality data... :wall:

Kind Regards,

Chad Lee

Hi Alex
Very interesting, I'm taking one of these to the British Natural History Museum on Wednesday to see if they can shed some light on the ID of this species as they have all the original description papers there, not to mention many many type specimens.

 

[Nazgul]

Hi,

thanks, Chad. I found the citation in the bibliography of the Catalog. Unfortunately I´m not at home until Sunday evening so I won´t be able to order the paper before.

But when I read your post it came to my mind that I´m having another paper on the comparison of C. gracilis and C. margaitatus in my possession. As far as I remember it´s not by Wagner. I will have a look at it when I´m home again. It could be useful to see if it´s really C. margaritatus or not.

Greetings
Alex

 

[Ythier]

Very interesting Alex, good job, thanks :clap:
I've just a very little doubt about granulation. Last time, I wanted to ID a young P.villosus with a key, I'm now sure it's a villosus with some characters, but I saw that granulations (on chelae, cephalothorax...) wasn't exactly the same that on my key, there were the main features, but it was not exaclty the same granulation, so I think (I'm not sure) that granulation evolve between firsts instars and adult, I think it is more simple (or less complex) in the firsts instars, and I don't know if granulation is a good caracter to ID young instars.
But as you said, with pectinal counts and rows of denticles it's not a bicolor (btw, do you asked to Giorgio regarding localization of sampling ?)
Thanks again for you ID.
Greetings,
Eric
(PS. I apologize to english-speakers, I'm in a hurry and my english is awful, sorry :8o )

 

[Nazgul]

Hi,

I received an answer from Giorgio. He said a friend of him collected them in Costa Rica. Therefor the origin should be sure.

According to the origin it should really be C. margaritatus :? . Your answer, Eric, would lead into that direction either. Anyways I´ll check it with the gracilis - margaritatus comparison paper when I´m home again.

Greetings
Alex

 

[fusion121]

Does anyone have:

MARTIN-FRIAS, Eliézer and DE ARMAS, Luis F. Scorpions in Mexico: Comments on some species from Centruroides gracilis and C. margaritatus (SCORPIONES; BUTHIDAE) groups. J. Venom. Anim. Toxins, Dec. 2001, vol.7, no.2, p.331-331

This apprently deals with the taxonomy of the two species.

 

[Ythier]

Mmm...strange, I think also that a different colour morph of margaritatus is possible, but babies (mine at least) are very different and smaller than babies margs or gracilis...
Anyway, beautiful species

 

[Nazgul]

Hi,

today I checked this species again using this paper:
SISSOM W.D. & W. LOURENCO (1987): The genus Centruroides in South America (Scorpiones, Buthidae) - Journal of Arachnology 15: 11-28
It contains a rediscrpition of C. margaritatus with even more and more detailed figures for determination than in the Francke & Stockwell book. It also contains a table with the average number of denticle rows on the fixed and on the movable finger (of more than 120 examined specimens of C. margaritatus). The very most C. margaritatus are having 7 rows on the fixed finger and 8 rows on the movable finger. This species has 8 rows on both fingers. Unfortunately I was able to examine only 2 skins, but I will do it with further ones of course.

According to Lourenco and Sissom this species is not C. margaritatus. But it´s quite confusing that the number of rows on the fixed given by Lourenco and Sissom is 7 and the one given by Francke & Stockwell and Stahnke is 8. Lourenco examined over 120 specimens of C. margaritatus, Francke & Stockwell examined about 350 at least for the pectinal tooth count. If they counted the denticle rows of all these specimens isn´t mentioned.

The granulation on the pedipalps fits with the figures given by Lourenco & Sissom, the trichobothrial patterns don´t.

So, after all I still don´t know which species. Would be nice to know which paper´s to follow. The book "Scorpions of Costa Rica" and the paper were both published the same year. It will take some time until I´ll receive the paper Chad cited. Maybe it´ll help to lighten it up a bit.

Greetings
Alex

 

[Ythier]

According to Lourenco and Sissom this species is not C. margaritatus. But it´s quite confusing that the number of rows on the fixed given by Lourenco and Sissom is 7 and the one given by Francke & Stockwell and Stahnke is 8.

And do you asked to Kovarik ? He probably give 9 rows , and perhaps Fet give 10 ?
Greetings,
Eric

 

[redhourglass]

Hi !

Just a quick comment. The Wagner paper I spoke of doesn't provide a redescription of C. margaritatus. My apologies.

A good read though.

Good luck,

Chad

Hi,
It will take some time until I´ll receive the paper Chad cited. Maybe it´ll help to lighten it up a bit.
Greetings
Alex

 

[fusion121]

According to Lourenco and Sissom this species is not C. margaritatus. But it´s quite confusing that the number of rows on the fixed given by Lourenco and Sissom is 7 and the one given by Francke & Stockwell and Stahnke is 8. Lourenco examined over 120 specimens of C. margaritatus, Francke & Stockwell examined about 350 at least for the pectinal tooth count. If they counted the denticle rows of all these specimens isn´t mentioned.

Hi
I counted 8 rows of denticles on the fixed and moveable finger as you did, the Lourenco and Sissom paper says that C. margaritatus can have this many rows of denticles on the moveable and fixed fingers.

though its not a common number. The paper does also say:

Preliminary evidence indicates that C. margaritatus varies considerably in cuticular granulation, morphometrics, and pectinal tooth counts . These differences do not appear great enough in light of the current understanding of C . margaritatus to warrant specific or subspecific status for the different populations .

It seems within the limits of the variation in this species that C. margaritatus could well be the case. Anyway I'm taking one into the museum tomorrow to see what they have to say,

Image copyright:
SISSOM W.D. & W. LOURENCO (1987): The genus Centruroides in South America (Scorpiones, Buthidae) - Journal of Arachnology 15: 11-28

 

[Nazgul]

Hi,

yes, C. margaritatus fits in mostly (more than any other species described for Costa Rica). The differences in my examined specimens to certain drawings weren´t major ones and could have been cause I examined non-adult specimens.

Yes, Sissom & Lourenco say that C. margaritatus can have 8 rows on the fixed finger but it´s less than 1/7 of the examined specimens. It´s very unlikely that out of three examined specimens (1 you, 2 me) all of them turn out to have 8 rows. Nevertheless I´ll count the rows of all other specimens as soon as they have molted.


I´m very curious about the results of your visit in the museum tomorrow .

Greetings
Alex

 

[fusion121]

Hmm. I went to see Paul Hillyard, one of the arachnid curators, at the NHM today, unfortunately he admitted south american scorpions are not really his area. However he had a look and agreeded the evidence seems to point to C. margaritatus, however he said he would not trust an ID based on a 3rd instar scorpling, the ID/ID characters may become clearer when the scorpion matures. So I guess the identity of these scorpions will have to remain a bit mysterious for a while longer.

 

[G. Carnell]

did he let you check the scorp specimens from costa rica??