Phylogenetic evidence supports Leiocephalidae being the most basal extant member of the clade Pleurodonta, with it diverging from the rest of the suborder as early as the Late Cretaceous, about 91 million years ago.

[3] Phylogenetic analysis on the genus supports some members of the now-extinct Lesser Antillean Leiocephalus radiation being the most basal of the recent Leiocephalus, with the last-surviving members of this group, L. herminieri and L. roquetus, sharing traits not present in other curlytail lizards from the Greater Antilles and other areas, such as the absence of enlarged snout scales.

[6] Curlytail lizards formerly had a much wider native range, being distributed south to Jamaica and east to Puerto Rico and several of the Lesser Antilles.

The last surviving members of the Lesser Antillean radiation, L. herminieri of Guadeloupe and L. roquetus of Martinique, went extinct during the early-mid 19th century.

[10][11] Although it has been suggested that it also functions as a territorial display,[6] studies have been unable to find support for this, as the tail curling does not vary when another member of the same species is present.

[5] Primary threats to their survival are habitat loss (for example, expanding agriculture, charcoal production and grazing goats) and introduced predators (for example, small Indian mongoose).

[7][15] Some of these are only known from fossil or subfossil remains and became extinct in the Pleistocene or pre-Columbian era, but others such as two Lesser Antillean species and one from Navassa survived until comparatively recently, during the 19th century.

This mass disappearance of Leiocephalus from the Lesser Antilles may be due to their inhabiting dry forests in littoral areas that were heavily exploited and deforested by early colonists.