A new cave locality for Astyanax cavefish in Sierra de El Abra, Mexico

Luis Espinasa,Julien Fumey,Laurent Legendre,Sylvie Rétaux,Maryline Blin,Monika Espinasa

doi:10.3897/subtbiol.26.26643

Abstract

The characiform fish Astyanaxmexicanus 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 influential 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 30th cave locality, Chiquitita Cave, inhabited by troglomorphic A.mexicanus. Their morphology, eye histology, 16S rRNA DNA sequence, and smelling capabilities are analysed. This 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 connection to “Chica Cave” (small cave), which is among the most studied populations of Astyanax.

Highlights

The blind Mexican tetra Astyanax mexicanus De Filippi 1853 has become the main contributor in the understanding of the genetic and developmental controls of troglomorphic features
29 cave localities have been described for A. mexicanus (Mitchell et al 1977), all of which occur within the El Abra region, in Northern Mexico
The first cave to be described with a troglomorphic population of Astyanax mexicanus was Chica cave

Summary

Introduction

The blind Mexican tetra Astyanax mexicanus De Filippi 1853 has become the main contributor in the understanding of the genetic and developmental controls of troglomorphic features. It is ranked among the influential model systems in evolutionary developmental (EvoDevo) biology (Jeffery 2001; Jeffery 2012). The cavefish have a conspecific surface-dwelling morph which lives in nearby surface streams throughout most of México. Both the eyed, pigmented surface morph and the eyeless, depigmented cave morph remain inter-fertile, making the species well-suited for experimental manipulations (Jeffery 2012; Elipot et al 2014). Granadas and La Joya, have been described for the closely related species of Astyanax aeneus in Guerrero, Southern Mexico (Espinasa et al 2001; Kopp et al 2017)

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