A new cave locality for Astyanax cavefsh in Sierra de El Abra, Mexico 39 A new cave locality for Astyanax cavefish in Sierra de El Abra, Mexico Luis Espinasa 1 , Laurent Legendre 2 , Julien Fumey 3 , Maryline Blin 4 , Sylvie Rétaux 4 , Monika Espinasa 5 1 School of Science, Marist College, 3399 North Rd, Poughkeepsie, New York 12601, USA 2 UMS AMAGEN, CNRS, INRA, Université Paris-Saclay, Gif-sur-Yvette, France 3 Évolution, Génomes, Comportement, Écologie. CNRS, IRD, Univ Paris-Sud. Université Paris-Saclay, 91198 Gif-sur-Yvette, France 4 Equipe Développement Evolution du Cerveau Antérieur, Paris-Saclay Institute of Neuroscience, CNRS and University Paris-Sud and Paris-Saclay, 91198 Gif-sur-Yvette, France 5 Department of Mathematics, Science, Biology, Engineering and Technology, SUNY Ulster, Stone Ridge, USA Corresponding author: Luis Espinasa (Luis.espinasa@marist.edu) Academic editor: O. Moldovan |  Received 13 May 2018  |  Accepted 14 June 2018  |  Published 4 July 2018 http://zoobank.org/29CA8372-4D22-4625-8759-990B8C273E79 Citation: Espinasa L, Legendre L, Fumey J, Blin M, Rétaux S, Espinasa M (2018) A new cave locality for Astyanax cavefsh in Sierra de El Abra, Mexico. Subterranean Biology 26: 39–53. https://doi.org/10.3897/subtbiol.26.26643 Abstract Te characiform fsh Astyanax mexicanus comes in two forms, a surface-dwelling morph which lives in the rivers of North and Central America and a blind, depigmented cave-dwelling morph which inhabits caves in Mexico. In recent years, this species has arguably become among the most infuential model system for the study of evolutionary development and genomics in cave biology. While recent articles have analysed in great detail Astyanax genetics, development, physiology, phylogeny and behaviour, there have been comparatively few recent studies concerning its ecology and in particular its biogeography. Mitchell et al. (1977) reported the species inhabiting 29 caves in the Sierra de El Abra region. Despite the elapsing of over 40 years and the latest surge of interest in the model, not a single new cave locality had been described for the species. We describe here a new and 30 th cave locality, Chiquitita Cave, inhabited by troglomorphic A. mexicanus. Teir morphology, eye histology, 16S rRNA DNA sequence, and smelling capabilities are analysed. Tis cave represents the southernmost extension for the cave morph’s habitat within the Sierra de El Abra. Its name, Chiquitita Cave (Tiny Cave), was chosen in reference to a potential hydrologic con- nection to “Chica Cave” (small cave), which is among the most studied populations of Astyanax. Keywords Astyanax, Chica Cave, Sierra de El Abra, troglomorphy, Troglobite Subterranean Biology 26: 39–53 (2018) doi: 10.3897/subtbiol.26.26643 http://subtbiol.pensoft.net Copyright Luis Espinasa et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. RESEARCH ARTICLE Subterranean Biology Published by The International Society for Subterranean Biology A peer-reviewed open-access journal