how to dinstinct Cambarellus shufeldtii and texanus

[bluedd]

Cambarellus(Dirigicamberus) shufeldtii
Cambarellus(Pandicambarus) texanus

This two Crayfish under different sub-genus, but their out-look are very similiar.

especially,when they are both in brown in colour.

I searched a lot of arictles, pictures and videoes.

But I still have no idea how to distinct them.

I hope someone can tell me what are the differences between them.