Rare events of cyclopia and melanism among deep-water snailfishes (Liparidae, Scorpaeniformes)

Abstract

Natural anomalies of fish eyes are noted occasionally and were never previously reported for snailfishes (Liparidae). Among fishes melanism is occurred in the nature relatively rare and sometimes associated with intergeneric hybridization or pathologic invasion. Until now the cases of melanism among fishes were known only for some paddlefishes (Polyodontidae), gars (Lepidosteidae), herrings (Clupeidae), livebearers (Poeciliidae), carps (Cyprinidae), loaches (Cobitiidae), salmons (Salmonidae), cods (Gadidae), rockfishes (Scorpaenidae), and righteye flounders (Pleuronectidae). Melanistic specimens of snailfishes were never previously reported. The first records of single-eyed specimen of round snailfish, Careproctus roseofuscus, and melanistic specimens of dimdisc snailfish, Elassodiscus tremebundus, and undescribed species, Careproctus cf. cyclocephalus, are documented. Some external characters of single-eyed and melanistic specimens are given and their photographs are provided.