Small, rare and trendy: traits and biogeography of lizards described in the 21st century

The pace of new reptile species descriptions, especially of new lizard descriptions, is rapidly increasing. The number of recognized lizard species has increased by more than 30% since the turn of the century. I examined the traits of newly described lizard taxa, and compared them to those of species described earlier, to predict where new species will be found, what traits they have, and whether they are likely to be more extinction-prone than well-known species. I compiled data on the biogeography and ecology of newly described forms and examined the relationship between these traits and the date of description. As expected, new descriptions are generally of small species, predominantly with small geographic ranges. Most species have been described from the Oriental Realm, whereas few new species were described from Africa. New descriptions are disproportionally biased in favor of geckos and of nocturnal species – and, surprisingly, contain few subterranean forms. Newly described lizard species are more likely to be threatened with extinction and may be more susceptible to population decline. Although the rate of new lizard descriptions is still accelerating, this work contributes to predicting what types of species are likely to be found in the future – and where. The small ranges of such species, in regions suffering from severe habitat degradation, suggests that strong mitigation measures are needed to ensure that many of these species will not be lost shortly after being described.