[1][2] The holotype of Eurofluvioviridavis, SMNK.PAL.3835, was found in the lower middle Eocene Messel Pit, near Darmstadt, Germany, in the MP 11 Mammal Paleogene zone.

The palate is not heavily ossified, unlike in some extant birds with wide, flat beaks, and there are no basipterygoid processes.

The ulna is longer than the humerus, with eight to thirteen quill knobs indicating a relatively low number of secondary feathers.

The feet show a semi-zygodactyl arrangement, and the ungual phalanges are raptor-like, possibly indicating that Eurofluvioviridavis could grasp with the foot.

[3] Cladistic analyses support a relationship between the genera Vastanavis, Avolatavis, and Eurofluvioviridavis in the family Vastanavidae.

This is in the contrast to the long tarsometatarsi plesiomorphic to the Australaves, the clade including falcons, parrots, and songbirds, which appears to indicate that a short, stocky tarsometatarsus was plesiomorphic to Pan-Psittacopasseres, the total group including parrots, songbirds, and their stem-lineage representatives.