Sexing from underside?

Lost_Tarantula

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I have read that it is possible to sex a tarantula from the underside. However, I am horribly inexperienced at this. The following picture is the underside of my B. smithi, which was sold to me as a female. Can anyone back that? Thanks atavuss for bringing to my attention that Petco has some sketchy smithi's. ;)

Hope someone out there can help.

-LT
 

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Code Monkey

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Your picture is not the best, but if I had to guess, I'd lean towards male, but I can't tell positively from your picture. I've included the below shot to help you out though.

Where I've circled in yellow is what you want to pay attention to. On a female there will be a distinct blackened/dark brown area where the opening to the genital slit has become hardened, they look sort of like plastic lips on mature females, but the beginnings are evident on large juveniles. A male just has the epigastric furrow extending across the abdomen immediately below the anterior book lungs, the groove is of equal thickness and has no distinct sclerotized area.

Where I've circled in red is another sort of clue it's possibly a male. The anterior book lungs are spaced very closely on this specimen and that's a male trait. These aren't *that* close though.

Now, this could all be an artifact of your photo, so wait until there's some more input and take a second look yourself before you go beating up your dealer ;)

Arguing against maleness is the out of focus area on the furrow which may be lips, I just can't tell, and the book lungs also form a slight angle, which is a female trait.
 

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Botar

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Here you go CM

Try your John Madden work on this one. It's an A. geniculata (female, IMO) and the pic is a bit clearer.

Botar
 

Tangled WWWeb

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I'm certain that ( the geniculata) is a female. On the smithi I thought male at first but the photo isn't clear enough for me to be sure.

John
 

Code Monkey

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Botar, that looks like a girl, you can see the thickened, shiny area of the lips and the "dish" between the book lungs is shallow like on a female.

I've put the two shots side by side to show the contrast in the area between the book lungs. Still, I can't be sure without better focus. Once you get used to seeing the genital lips on a female, the male furrow looks completely different, but you need to actually be able to see the furrow clearly to tell
 

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Code Monkey

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Here's another shot I took of two exuviae of mine. One is my second B. smithi male who moulted for me last night (Left Side), the other is an older exuviae of my female A. bicoloratum (Right Side).

As you can hopefully see, the groove on the male is just an indentation, the only area of sclerotization is just a teeny circle dead center. On the female, the groove is actually an opening to the spermathecae and the sclerotization extends for the full epigastric furrow like plastic lips.

EDIT: My original label of which side was which was wrong, sorry if I confused anyone
 

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Code Monkey

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Much better picture.

I hope you didn't pay too much extra for a "female" because that looks very, very masculine to me. The furrow is of even thickness across the whole abdomen and there is no sign of sclerotized lips about a genital opening, and, you can just make out the little patch of epiandrous fusilae anterior of the furrow.
 

Vayu Son

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><

Looks like a male to me as well. Note the "triangle" shape of hairs anterior of furrow as noticed by c_m.


-V
 

Lost_Tarantula

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CM -

I paid $50. Worth going back to the Petco to dispute? It's under a 15 day guarantee right now.

-LT
 

Code Monkey

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Originally posted by Lost_Tarantula
CM -

I paid $50. Worth going back to the Petco to dispute? It's under a 15 day guarantee right now.

-LT
That depends on whether you think $50 is worth the gamble on a breeding loan sometime in the next 18 months. $50 could be considered a fair market value for an immature male, but if it was sold as a female and that's what you wanted, I'd go back and exchange/return it.
 

Botar

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IMO, $50 is a good price for a male of that size. There are always people looking for males for a breeding loan... myself included. Just depends on your intent for the T. If it is a "pet" that you'd hoped to have for years to come... take it back. If the thought of turning that male over into a couple hundred babies interests you (and it's a gamble), then keep it.

Botar
 

Immortal_sin

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I would say definately male as well. Unfortunately, I've had lots of experience with maturing males lately! I just looked at the underside of my A geniculata, and yup, he's a male too!
As a mature male, you'll probably have your choice of whom to send him to for breeding, but getting an eggsac out of B smithi is not the easiest thing to do either. LIke Botar said, it depends on what you would like out of him.
 

Lost_Tarantula

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Well I have a need for some good debate. I'll go back, see if they can lower the price, not because the price was unfair, but that it was sold under false pretenses. They may not have a female...this guy said that they were ALL female, that he got them all together from the same place, if I remember correctly. Besides, I don't think I can pull of a sexing with my current experience, not to mention that the other smithis are smaller than this one. But slashing the price some shouldn't be too hard. I mean, he tried to show me that this smithi didn't have tibal spurs. Come on! ;P

-LT

P.S. I'll try to pull off a sexing on site, but the hardest part is to get it upside down, IMO. I'll see what I can do, and keep you updated whether you like it or not. ;)
 

Code Monkey

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She finally cooperated

This is a shot of my probably penultimate female curly hair, this is what you would want to be looking for on a B. smithi if you want a female:
 

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Lost_Tarantula

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Re: She finally cooperated

Originally posted by Code Monkey
This is a shot of my probably penultimate female curly hair, this is what you would want to be looking for on a B. smithi if you want a female:
Thanks, that will help alot. I'll see what I can do. Stir up trouble, no doubt. ;)

Thanks for everyone's help.

-LT
 

atavuss

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Re: Re: She finally cooperated

Originally posted by Lost_Tarantula
Thanks, that will help alot. I'll see what I can do. Stir up trouble, no doubt. ;)

Thanks for everyone's help.

-LT
so........what happened? did you do the right thing and just buy all the smithis they had? LOL! I have a sneaking hunch that a dealer somwhere is dumping all the smithis he can sex out as male on petco. out of the 4 I got at petco three are males.......
Ed
 

Lost_Tarantula

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Re: Re: Re: She finally cooperated

Originally posted by atavuss
so........what happened? did you do the right thing and just buy all the smithis they had? LOL! I have a sneaking hunch that a dealer somwhere is dumping all the smithis he can sex out as male on petco. out of the 4 I got at petco three are males.......
Ed
Well I made a phone call today. The woman (manager) at the other end asked how I knew that it was a male rather than female, and I gave her:
1. The epigastric furrow was a straight line between the anterior booklungs
2. The book lungs aren't angled enough, they are nearly horizontal
3. The book lungs are close together

I thought that would satisfy her enough to let me come in later with a grant to look at their other Redknees, but the conversation went like this after that:

Woman: What website did you get that off of?
(Instead of giving her that "Quick and Dirty Tarantula Sexing" website that explains underside sexing, I went with arachnopets)
Me: I am a member of a tarantula message board that is frequented by many experienced hobbyists. One of which has been keeping New World T's for 16 years. (Hats off to Code Monkey!)
Woman: Any of them professional?
(What the hell? Sixteen years of experience isn't enough for you? Just to make sure...)
Me: Define professional.
Woman: Has a degree.
Me: No. ( I am convinced that their expert, James, has a degree in herps, not T's)
Woman: Well I am not going to take the word of some guy in his apartment snapping photo's over James' word. If you go to www.herp.com, which is a PROFESSIONAL website, and any information there conflicts with what James said, I'd be happy to exchange it for you. (not surprisingly, herp.com isn't a website, and herpe.com is a website selling herpes meds..yeah...conflicting information there. :rolleyes: )
Me: (planning on blazing through the doors tomorrow) Uh-huh.
Woman: You know, cause I'm not going to just take the word of another hobbyist - blah blah blah
Me: Uh-huh. Bye.
Woman: Bye.

Tomorrow, or when I find time, I am going in there to talk to James himself. He's the one who pointed out that this immature doesn't have tibial spurs, and is therefore a female. Hear that guys? This is the holy professional, who is apparently smarter than all of you apartment living photo snapping lowly hobbyists. :rolleyes:

What a crock.

-LT
 
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Code Monkey

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If I were you I'd just return it after that b.s. run around since it's supposedly under guarantee. Unless James is just ignorant as opposed to stupid you're unlikely to get anywhere with him. Hopefully you paid with a credit card. Nothing like threatening to contest charges to get companies to change their tune :)
 
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