What evidence do scientists use to classify rodent families and suborders?

To classify rodent families and suborders, scientists rely on a diverse range of evidence to form hypotheses about evolutionary relationships. Because the fossil record for rodents is incomplete prior to the Late Paleocene, researchers must synthesize data from multiple, often unrelated sources to refine these classifications.1

Key evidence used by scientists includes:

• Comparative Anatomy: Researchers analyze the structure of the jaw and associated musculature, as well as the anatomy of the head and postcranial skeletons.1
• Dental Features: The histologic structure of incisor enamel layers is a critical diagnostic tool.1
• Developmental Biology: Scientists examine the embryonic development of extraembryonic fetal membranes.1
• Molecular Data: Modern classification increasingly incorporates analyses of DNA to determine evolutionary affinities.1
• Fossil Record: Discoveries of new fossils help test and update existing hypotheses regarding the relationships between different rodent groups.1

While some historical classifications focused primarily on the conformation of the lower jaw, current formal systems integrate these various biological and historical data points to better understand the complex evolutionary history of the order Rodentia.1