Preliminary study on differences characterizes the populations of olm (Proteus anguinus) in cave and those found in epigean environment

The olm ( Proteus anguinus ) is considered the most representative example of all stygobiont fauna. Nevertheless, it also reported in some spring habitats Friuli Venezia Giulia (North-eastern Italy). Springs are intriguing that border two strongly distinct environments: surface and underground. They may provide environmental pressures to animals promoting new adaptations. aim this study verify if there differences structural morphology head presence melanin skin between olms found caves compared individuals external environment. During 2021, 28 olms, 18 from underground 10 sites, were photographed standard conditions with a metric reference. For each individual, only cephalic region has been considered. pictures processed using TPSdig software . picture we placed 2 landmark homologues, matching emergence gills branches, 48 semi-landmark define contour head. With regard mm removed tail analyzed through spectrophotometer. results indicate significant effect environment on shape olm’s head, fact appears more elongated front narrower parietal coming hypogean In addition, use epigean show higher levels their skin. These findings first evidence occurring populations/sub-populations living those exploiting habitats.