Present study is an attempt to know the existence of colour change physiology of the cave fish Nemacheilus evezardi (Day) along a circadian time scale. Though, due to subterranean mode of life, practically this function has no survival value. The study has been conducted simultaneously in two different photoperiodic conditions (LD 00: 24 and LD 12:12 hr). The variation in different states of chromatophore has been computed with respect to different time points of the day. Results suggest that the phenomenon is lying completely disturbed in its in situ conditions. Interestingly, circadian rhythm in all the types of chromatophores were validated when the same fish was exposed under LD 12: 12 hr photoperiod.
Pradhan, Rohit K. and Jayant Biswas.
Towards regressive evolution: the periodic colour change behaviour of a troglophilic fish Nemacheilus evezardi (Day).
International Journal of Speleology,
Available at: http://scholarcommons.usf.edu/ijs/vol23/iss3/5