Polyglyphanodontia

Polyglyphanodontia, also known as the Borioteiioidea, is an extinct clade of Cretaceous lizards. Polyglyphanodontians were the dominant group of lizards in North America and Asia during the Late Cretaceous.

Chronology and distribution
Most polyglyphanodontians are Late Cretaceous in age, with the highest diversity in the group being known from East Asia. The oldest polyglyphanodontian, Kuwajimalla kagaensis, is known from the Early Cretaceous Kuwajima Formation of Japan. Early Cretaceous South American taxon Tijubina, and possibly also Olindalacerta, might also fall within Polyglyphanodontia or be closely allied to the group, but if so, they would be two of only four Gondwanan examples of an otherwise Laurasian clade (the other two, and the only unambiguous ones, being Bicuspidon hogreli from the Kem Kem Beds of Morocco and Cryptobicuspidon pachysymphysealis from the Quiricó Formation of Brazil). The group became extinct during the end-Cretaceous extinction event, the only major terrestrial squamate group to do so.

Ecology
Polyglyphanodontians were morphologically diverse. Chamopsiids, including Chamops, from North America have tricuspid teeth, and were generally small in size. Members of the family Polyglyphanodontidae primarily known from Europe and North America (including Polyglyphanodon, Paraglyphanodon, Dicodon and Bicuspidon) have large teeth that are transversely orientated, and were likely herbivorous as well as possibly ominivorous. The family Gilmoreteiidae have iguana-like teeth, with some polyglyphanodontians known from Asia having conical teeth. Some gilmoreteiids developed a complete lower temporal bar similar to that found in the tuatara, but is otherwise unheard of in lizards.

Classification
The classification of Polyglyphanodontia is contentious. They have been considered to be either most closely related to Teiioidea, or to Iguania, with both positions having been supported in recent studies. Cladogram after Xida, Niu and Evans, 2023.