A new genus and species in the South American sun-spider family Mummuciidae, Vempironiella aguilari gen. nov., sp. nov., is herein described from a series of specimens from the coastal desert of Punta Hermosa, Peru. Vempironiella can be readily distinguished from all other known mummuciid genera, by the absence of the cheliceral movable finger MM tooth and the presence of a diastema between the RFA and RFP teeth on the fixed finger. With this description, the number of valid species of mummuciids is 19, three of which have been described from Peru. Males of V. aguilari measure 3.90–5.85 mm in total body length making it the smallest solifuge species known to date. The cheliceral morphology of V. aguilari is discussed and some hypotheses on the function of morphology are provided.