C. marshalii. At what size should a horn be expected?

[Tim Benzedrine]

I'm not a newbie at tarantulas, of course, but I AM a newbie at OW's, specifically Ceratogyrus.. And I'm curious as to when it can be discerned (roughly) whether the spider will sport the "button" horn or the beginnings of a full-fledged female ornament.. Mine is probably somewhere around 2-1/2 inches. Normally, I'd just plop something in the enclosure for scale, but not with this species., and I'm not that good of an estimator of size. I'd post a photo, but it would probably get zapped over to tarantula sexing or the gallery and that's not really the point of this post, as it is actually a question. I am assuming that the answer would be the same in regard to my C. darling, but it is to small to even bother asking for an opinion. But it is growing fast, as did the marshalii.

I can of course provide a photo if that helps and is permitted. I'm just hesitant to do so because this is not a matter of sexing or a "Hey! Check out my C. marshalii!" sort of post.

 

[Liquifin]

At 3''+ it becomes night and day for C. marshalli as males will almost nothing but maybe a very, very, very small bump which is almost flat, whereas as a female will start to have a larger bump on the carapace. You'll know almost instantly that it's a male once you see how flat his horn is on the carapace

Here's my freshly molted male C. marshalli at 3''+ for reference.

 

[Tim Benzedrine]

Thanks for the info.

And since I can now play the ""Hey! He posted a picture first!" card I'll provide a shot that I took tonight. As an aside, to me, it looks like the "horn" is sort of heading towards the rea if it is going anywhere at all.. I bought it as a marshalii, but if it was mislabeled and is in fact a darlingi I'm okay with that. Well, apart from the fact that at a later expo, I bought a C.darlingi in the hopes of A) Scoring at least one female of one or the other, and B) so I could have an example of both. I have a lot of faith that the darlingi I purchased is indeed as was labeled because I think the source was a reputable vendor, but the marshalii is up in the air as it was purchased from a non-arachnid oriented table. They are both horned baboons, I'm certain, so if I have two rear-horns, so be it.

The "C. marshalii"

 

[Liquifin]

Thanks for the info.

And since I can now play the ""Hey! He posted a picture first!" card I'll provide a shot that I took tonight. As an aside, to me, it looks like the "horn" is sort of heading towards the rea if it is going anywhere at all.. I bought it as a marshalii, but if it was mislabeled and is in fact a darlingi I'm okay with that. Well, apart from the fact that at a later expo, I bought a C.darlingi in the hopes of A) Scoring at least one female of one or the other, and B) so I could have an example of both. I have a lot of faith that the darlingi I purchased is indeed as was labeled because I think the source was a reputable vendor, but the marshalii is up in the air as it was purchased from a non-arachnid oriented table. They are both horned baboons, I'm certain, so if I have two rear-horns, so be it.

The "C. marshalii"

View attachment 335564

Size would help a lot if you want to sex it by just looking at current picture, but it is leaning male for me based on your picture. It's hard to mislabel darlingi and marshalli, and I can tell you that C. marshalli and C. darlingi look nothing alike if you compare the carapace design and colors side by side. C. marshalli has the black striping on the carapace heading towards the center where the horn is. Whereas the C. darlingi has the more white/silver lining carapace heading towards the center where the horn is. Also note that the C. darlingi developed their horns much quicker at smaller sizes than the C. marshalli. Even mature males between C. darlingi and C. marshalli is hard to get mixed up if you know where to look on the carapace.

Here are some comparisons between the two :

Juvenile Female C. marshalli (Note the black striping on the carapace pattern)



Juvenile Female C. darlingi (Note the white/silver carapace pattern)

 

[Tim Benzedrine]

Thanks for the info! I'll look closer at the two, particularly at the Marshalii after another moult or two. . The Darlingi is still too small to really get a definitive look at, but they grow fast.

Gonna be somewhat disappointed if you are correct on the gender, but that's part of the tarantula keeping game. Won't be the first time I was disappointed.