Trying to understand

cold blood said:

yep....while both males and females have this, its much wider and more pronounced on a female.

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Vanessa said:

It is not just the same characteristics across the board spanning all genera and species. That is why it is always stressed to include the species and size when asking any sexing questions. Different species have different characteristics to look for and it isn't just one size fits all when it comes to what you're looking for. What size the individual is plays a huge role as well, since most characteristics aren't obvious until they are in the large juvenile stage.
It takes practice and looking at comparison photos (which this forum has literally thousands of).
Some genera - Aphonopelma, Brachypelma, Euathlus, Grammostola, Tliltocatl - contain many species whereby the female will have a distinct 'moustache' of contrasting white hairs above the furrow. That is what your photo is illustrating, yes.

Brachypelma albopilosum - 3"

• Vanessa
• May 4, 2016
• 6
• brachypelma brachypelma albopilosum female juvenile juvenile female

Some genera - Avicularia, Caribena - contain many species whereby the female will have a very distinct 'lip' structure that sets the females apart.

Avicularia metallica 3.5" Female

• Vanessa
• Oct 8, 2017
• avicularia avicularia avicularia morphotype 6 avicularia metallica female juvenile metallica sexing sub-adult subadult female

Some genera have neither - Cyriocosmus - so you have to judge whether the epigynum looks to have a gap at the bottom of it where the males will access with their emboli.

Cyriocosmus ritae Female - ~2"

• Vanessa
• Oct 21, 2019
• adult adult female cyriocosmus cyriocosmus ritae female peruvian black and white tarantula ritae sexing ventral

Moult confirmed female.

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