First report of Ignotornidae (Aves) from the Lower Cretaceous Gates Formation (Albian) of western Canada, with description of a new ichnospecies of Ignotornis, Ignotornis canadensis ichnosp. nov.

Ignotornidae is an avian vertebrate ichnofamily known from the Lower to middle Cretaceous (Aptian - Cenomanian) of North America (Colorado) and South Korea. The ichnogenus Ignotornis was first described from North America; however, in the eight decades since no Ignotornidae have been described from North America, and hitherto none have been reported from Canada. Here we describe the first ichnospecies of Ignotornis, Ignotornis canadensis ichnosp. nov. (Gates Formation, Lower Cretaceous, Albian), the first new ichnospecies of Ignotornis to be described from North America since the original description of Ignotornis mcconnelli, and the first report of Ignotornidae from Canada. Ignotornis canadensis ichnosp. nov., while morphologically similar to Ignotornis mcconnelli, is larger and has a relatively longer digit I impression than Ignotornis mcconnelli, and has digit I impressions with a similar orientation to those of the ichnogenus Goseongornipes. Discriminant analyses show that Ignotornis canadensis ichnosp. nov. is most similar to the ichnogenera Goseongornipes and Hwangsanipes due to the divarication of digits I-II and II-III. The apparent sinusoidal digit III impression in Ignotornis canadensis and other Ignotornidae is due to water saturated sediment not completely preserving digital pad impressions, rather than a morphologic feature of digit III. While the majority of ichnospecies of Ignotornidae are from South Korea, and while Asia currently contains the largest diversity of avian ichnotaxa from the Cretaceous Period, the apparent lower diversity of Cretaceous avian ichnotaxa from North America may be preservationally controlled, and will be resolved with a greater focus on Early Cretaceous ichnofauna in North America.