MEPS 626:227-231 (2019)  -  DOI: https://doi.org/10.3354/meps13078

ABSTRACT: The Antarctic icefish subfamily Channichthyinae have evolved a range of unique physiological adaptations that permit them to exist without the oxygen-transporting haemoglobin proteins, and some species even lack the intracellular oxygen-binding protein myoglobin. These physiological adaptations have been the subject of numerous studies, but the simple problem of why this group lost such a valuable adaptation during their evolutionary history has never been addressed. Here, I hypothesise that it happened during a period of iron deficiency in the Southern Ocean after the Antarctic ecosystem acquired its recent oceanographic properties. A lower dependence on dissolved iron in this new environment probably gave some evolutionary advantages to fish species that did not require this element in essential amounts for their physiological needs.

KEY WORDS: Icefish · Channichthyinae · Haemoglobin · Antarctic · Evolution