Amblypygid ID?

[zyxw10]

I purchased a breeding trio of tailless whip scorpions from my local pet store. The sign said Central American Tailless whips. Unfortunately, the male had a bad molt and died. I'm still interested in breeding them, but I can't remember the scientific name and I want to make sure I'm getting the right ones. The female is in the photo. Anyone able to give a positive ID?

 

[Sarkhan42]

Are you sure this is a female? This looks like a male Phrynus cf whitei from Nicaragua to me.

 

[mantisfan101]

Looks mLe to me but we need pics of operculum or molt to be sure

 

[zyxw10]

I’ll try and get a photo of the underside tonight, but I thought females had the shorter pedipalps in relation to the legs. Unless I’m mistaken?

 

[Sarkhan42]

I’ll try and get a photo of the underside tonight, but I thought females had the shorter pedipalps in relation to the legs. Unless I’m mistaken?

This is often parroted for Damon diadema- but is not the case for most species in the hobby, including the species you have. This species does have some dimorphism in which adult males will darken to an even gray/black, be proportionally lankier, and develop a slight curve/bulge to the tibia of the palps, but it’s much less cut and dry.

Mantisfan is correct in that if you want a method that is 100% reliable for all species, the genital operculum or a molt is the way to go.

 

[zyxw10]

Good to know, thank you. I’ll get photos of their undersides later tonight.

 

[Edan bandoot]

One of the nicaragua Phrynus sp

 

[zyxw10]

This is the underside of the larger of the two.

 

[mantisfan101]

Male, and in my experience sexing via checking pedipalps is perhaps the worst way to sex any amblypygid, especially with different sp coming in being mislabelled

 

[Sarkhan42]

Agreed male with the posted ventral.

 

[zyxw10]

How can you tell? Like, what should I look for if I want to tell the difference between a male and a female?

 

[Sarkhan42]

How can you tell? Like, what should I look for if I want to tell the difference between a male and a female?

You're looking for differences in the genital operculum. Males generally have a more rounded shape, and females a more angular trapezoidal, varying species to species. (Damon, Euphrynichus, and Phrynichus also have a fringe of red setae on the posterior margin that can give females away) I'm struggling to find a clear cut side by side for Phrynus online, but have this one of two other species that should give you an idea of what I mean:


(credit Jordan Cadiot, not sure if he has an account here)

As you can see it still requires some familiarity to be able to differentiate confidently, and every species is different which makes it even more difficult. Orin McMonigle has some excellent examples in his book "Breeding the worlds largest living arachnid", including of some Phrynus species, if you're further interested in Amblypygi.