Large Mesozoic mammals fed on young dinosaurs

Area of Science:

• Paleontology
• Vertebrate Zoology

Background:

• Mesozoic mammals are often depicted as small, insectivorous creatures overshadowed by dinosaurs.
• The largest known Mesozoic mammal with substantial remains is Repenomamus robustus.

Observation:

• A new, larger species of Repenomamus was discovered with well-preserved skeletal remains.
• Stomach contents of R. robustus revealed the fossilized remains of a juvenile Psittacosaurus.

Findings:

• This study provides the first direct evidence of carnivorous triconodont mammals consuming small vertebrates, including young dinosaurs.
• Mesozoic mammals exhibited a wider range of body sizes than previously understood.
• The newly discovered Repenomamus species is 50% larger in skull length than R. robustus.

Implications:

• Some large Mesozoic mammals occupied diverse ecological niches, potentially competing with dinosaurs for resources.
• This discovery reshapes our understanding of mammalian evolution and ecological roles during the Mesozoic Era.