Cretaceous Mammals from Montana

Area of Science:

• Paleontology
• Vertebrate Paleontology
• Mammalian Evolution

Background:

• The Cretaceous-Paleogene boundary marks a significant transition in mammalian evolution.
• Understanding faunal changes across this boundary is crucial for reconstructing early mammalian diversification.

Purpose of the Study:

• To summarize Cretaceous mammal faunas and their transition into the Paleocene.
• To revise the classification and understanding of multituberculate mammals.
• To describe new mammalian genera and species from the Late Cretaceous.

Main Methods:

• Faunal analysis of Late Cretaceous and early Paleocene mammal assemblages.
• Comparative osteology for the description of new taxa.
• Skeletal restoration and phylogenetic analysis of multituberculates.

Main Results:

• Four Tertiary mammal families (Eucosmodontidae, Taeniolabididae, Leptictidae, Arctocyonidae) and the order Condylarthra are extended into the Cretaceous.
• New genera (Cimexomys, Stygimys, Procerberus, Protungulatum) and a species of Catopsalis are described.
• A multituberculate skeleton is restored, and their classification is revised.

Conclusions:

• The Late Cretaceous mammal fauna shows significant overlap with early Paleocene forms.
• The revision of multituberculate classification provides new insights into their evolutionary history.
• The described new taxa highlight the diversity and complexity of mammalian faunas during this transitional period.