Acaulona or Xanthomelanopsis ??? (French Guiana & Surinam)

Acaulona or Xanthomelanopsis ??? (French Guiana & Surinam)
Acaulona & Xanthomelanopsis look very similar to Pennapoda spp. but without the leaf-like antero-dorsal bristles on the hind tibia. The only difficulty with these flies is that I just can’t make up my mind whether they have enough dorsocentrals to qualify as Xanthomelanopsis.