We describe and illustrate Aristolochia lorenae, a new species found in the state of Pará, Brazil. The new species is assigned to subseries Anthocaulicae F. González, which is characterized by the presence of extremely short cauliflorous and/or ramiflorous racemes that have shortened internodes and flowers subtended by a small bract. We provide a taxonomic description complemented with illustrations, photographs, a map of geographical distribution, and a conservation assessment based on field observations. In addition, a detailed comparison of the new species and its closely morphologically similar species as well as a key to species of Aristolochia subseries Anthocaulicae are also presented.