On this cover from Paraguay (my very first) you can see a stamp which is part of the 2012 UPAEP issue from Paraguay. The topic was Myths and Legends and the nice sheet from Paraguay shows different stamps of "Los Hijos de Tau y Kerana". The stamp on this cover shows "Teju Jagua", the first son of Tau and Kerana and one of the seven legendary monsters of Guaraní mythology. The Tupi-Guarani mythology is the set of narratives about the gods and spirits of the different Tupi-Guarani peoples, who are living in the south-central part of South America, especially in Paraguay and parts of the surrounding areas of Argentina, Brazil, and Bolivia.
Stamp:
America UPAEP 2012 - "Myths and Legends" (from a set of 7) - Issued: 07-06-2012
Many thanks to Gabriel!