It contains one species, P. glarniensis from the Early Oligocene-aged Matt Formation of Canton Glarus, Switzerland.

It is known from a partially complete but poorly-preserved fossil skeleton knwon from the famous "Glarus Fish Slates".

[3] It was initially described as a passeriform by von Meyer (1844) due to its small size, but Olson (1976) reclassified it as an early motmot, noting several close similarities of its skeleton to extant Momotidae, including its rather flattened bill.

However, more recent studies have noted that it as some traits not present in motmots either, so it is now considered an indeterminate coraciiform.

[3] The genus name "Protornis", despite being preoccupied by this genus, was also used for an ichnogenus of animal tracks that was interpreted as representing early bird footprints, such as Protornis bavarica from the Jurassic of Germany, thought to represent Archaeopteryx footprints.