Pumiliornis tessellatus is an ancient bird from the Middle Eocene of Messel, Hesse, Germany. It is described as a wren-sized[1] anisodactyl bird with a long, slender bill and strong hallux. Its species name tessellatus, meaning "mosaic" in Latin, is a reference to its unusual distribution of characters and uncertain phylogenetic placement.[2][3]

In 2014, a new specimen of Pumiliornis was described that showed preserved stomach contents of pollen grains from a eudicotyledonous angiosperm, making it the earliest fossil evidence of flower-visiting behavior in birds.