Therapsids, also known as theriodonts, are a diverse group of reptile-like mammals that emerged during the Permian period, approximately 270 million years ago. They are an extinct order of synapsids, characterized by their unique anatomical features and evolutionary significance. The term "therapsid" is derived from the Greek words "thera" meaning beast, and "saimos" meaning lizard.
Therapsids are notable for being a transitional group between reptiles and mammals, representing a significant milestone in the evolution of vertebrates. They possessed many mammalian characteristics such as differentiated teeth, a secondary palate, and a more efficient respiratory system. These advancements allowed therapsids to become more efficient predators and adapt to various ecological niches.
Classified into several families, therapsids exhibited a wide range of morphological variations. From small, agile insectivores to enormous, predator-like forms, therapsids demonstrated great variation in size, locomotion, and feeding habits. Some notable representatives include the Gorgonopsians, herbivorous Dicynodonts, and the later cynodonts.
The therapsids were remarkably successful and dominated the land ecosystems for millions of years until their extinction at the end of the Triassic period, approximately 200 million years ago. Their decline and eventual extinction were likely due to the emergence and diversification of the dinosaurs.
Studying therapsids is crucial for understanding the evolutionary history of mammals, as they hold significant insights into the origins and development of many mammalian features that we recognize today.
