Available online at scholarcommons.usf.edu/ijs / & www.ijs.speleo.it International Journal of Speleology

morphological adaptation and do not complete their life cycle there. 2) Troglophiles alternate between the epigean and hypogean habitats or live permanently in subterranean habitats; they show some moderate adaptation, such as partly reduced eyes and adaptations to compensate for the lack of visual orientation. Some among these do not complete their life cycle underground, while others do. 3) Troglobionts complete their life cycle in a hypogean environment, and most of them clearly show troglomorphic characteristics, like eyelessness and depigmentation. In contrast to the frequent preference for these three ecological groups, Novak et al. (2012) found that, on the one hand, trogloxenes and troglophiles together represent a group of variously adapted species, rather than two ecologically clearly separated categories, and, on the other hand, troglobionts divide into two strictly separated subgroups. Invertebrates are ectothermal and at their critical thermal minimum they enter chill-coma, where neuromuscular transmission and movement ceas