New Ichnotaxa of Mammal and Reptile Tracks from the Upper Paleocene of Alberta

Abstract

Only two vertebrate trackways are known from the Paleocene of western Canada and are among the few Paleocene vertebrate trackways known worldwide. A natural cast trackway consisting of five prints (three pes, two manus) on a fallen block was found along the Red Deer River, near the town of Red Deer, Alberta, in 1927. The discoverers, Ralph Rutherford and Loris Russell, identified the strata the track block had fallen from as belonging to the Paskapoo Formation (upper Paleocene: middle Tiffanian). The trackway was attributed to a mammalian track-maker in two subsequent publications. However, the prints are more characteristic of a reptilian (crocodylian) track-maker. A natural cast track-bearing block was discovered on Signal Hill in the city of Calgary during the preparation of a new residential subdivision in 1990. The large track-bearing block was found in a rock pile but is suspected to have originated from strata belonging to the Porcupine Hills Formation (Upper Paleocene: late Torrejonian), which was being excavated at the time. This large slab contains twelve prints (six pes, six manus) and is associated with extensive mud cracks. The mammalian affinity of the trackmaker was recognized by researchers from the Royal Tyrrell Museum of Palaeontology.