Hope in the dark: discovery of a population related to the presumably extinct micro-endemic Blunt-headed Salamander (Ambystoma amblycephalum)

ABSTRACT

We report on the discovery of a population related to the Blunt-headed Salamander (Ambystoma amblycephalum), a micro-endemic axolotl from Mexico scientifically confirmed only once since its original description in 1940, and now presumably extinct. In 2018, paedomorphic and metamorphosed adults, as well as clutches and larvae, were found in a cattle pond at Nahuatzen, Michoacán state, Mexico, ~60 km away from the type locality (Tacícuaro). Morphometric comparisons suggested high similarity with the type series of A. amblycephalum, while mitochondrial DNA barcoding (16S and control region) revealed close (but imperfect) matching to a reference sequence. We gathered data on life history and ecology of this population, which could be the only extant relic of A. amblycephalum. Its highly limited distribution and presumably low population density are hallmarks for a high risk of extinction, and alarms on the critical situation of many micro-endemic salamanders of Mexico, hence calling for immediate conservation actions.

KEYWORDS:

• Axolotl
• diversity
• endemism
• extinction
• michoacán
• genetic barcoding

Acknowledgments

We are deeply grateful to David B Wake, Daniel Escoriza, Jérôme Maran, Mian Hou, AmbystoLab and OctoLab for their help and support. We also thank the Secretaria de Medio Ambiente y Recursos Naturales (SEMARNAT) of Mexico for collection permit.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author contributions

AH designed the study. AH, JR, EJ, ALS-P, VCR-E and PBN conducted fieldwork. CD and SD performed genetic analyses. AH and CD drafted the manuscript, which was critically improved by all coauthors.