Gonolobus foetidus species from southern South America is transferred to Matelea, being characterized by its horizontal pollinia and anthers lacking dorsal appendages (Matelea foetida). A new species, Matelea calchaquina, from arid environments of northwestern Argentina is described and illustrated; data on its habitat, distribution, and phenology is provided. This is a distinctive species within Matelea due to its white flowers with narrow, tubular corollas, which suggest pollination by nocturnal moths. The difficulties in delimiting genera of Gonolobinae based on floral characters are discussed. A key to the species of Matelea from Argentina is included.