Michael L Yuan, Rayna C Bell, Edward A Myers

Accurate assessment of historical species ranges is important for conservation science and management. Inaccurate historical species ranges can lead to incorrect assumptions about local extinctions, population trends, and potential sites for reintroductions. Yet, historical knowledge is often lacking for many species. Here, we examine the case of the bearded anole, Anolis pogus, which has long believed to have been recently extirpated from the island of Anguilla. We addressed the evidence for the historical presence and recent local extinction of A. pogus on Anguilla using species abundance modeling, fossil and extant morphological data, and archival DNA sequencing from museum specimens. We found that although viable habitat remains on Anguilla, it is highly fragmented. We also falsified the prior characterization of two size classes of anoles in Anguilla's fossil deposits as evidence for two species (A. gingivinus and A. pogus) by comparing with the size distribution of both species on neighboring St. Martin. Instead, our data indicate that fossil deposits on Anguilla likely correspond to males and females of the larger anole species, A. gingivinus, with no fossil evidence for A. pogus. Finally, we sequenced all known museum specimens of A. pogus from Anguilla and demonstrate that these specimens were incorrectly identified. Together, our results show that there is no evidence for the historical presence, and thus no evidence for the local extinction, of A. pogus on Anguilla. These data are vital for the appropriate management of this species of conservation concern. Furthermore, our study provides a case study for the critical assessment of historical species ranges and narratives of extinction.