New specimens of Late Jurassic and Early Cretaceous decapods from Argentina document new species and new occurrences. Pehuenchia Rusconi, 1948, originally placed within Palinura and subsequently placed within Callianassidae or Mecochiridae, is herein referred to Mecochiridae. The type species, Pehuenchia tellecheai Rusconi, 1948, is herein illustrated photographically for the first time. A second species of Pehuenchia is herein referred to a new genus, resulting in Zapalianassa, new genus, and Zapalianassa magna (Rusconi, 1948), new combination, and additional specimens of the species are illustrated. A new species of the mecochirid genus Huhatanka, Huhatanka australis, in southern Argentina extends the geographic range from the Western Interior Seaway and the geologic range from the late Early Cretaceous to the early Early Cretaceous. A species of Huhatanka described from Iran is herein moved to Meyeria, resulting in Meyeria iranica (Yazdi et al., 2010), new combination. Additional specimens of Protaxius paucisaetosus Andrada et al., 2022, extend the range of the species southward. Late Jurassic and Early Cretaceous decapod occurrences in Argentina are currently known from Glypheidea, Astacidea, and Axiidea.