New Data on the Morphology and Distribution of Two Rare Species of Deep-Sea Anglerfish from the Families Linophrynidae and Himantolophidae

Abstract

New information is given on the morphology and distribution of two little-known species of ceratioid anglerfish—Linophryne pennibarbata and Himantolophus appelii. The species L. pennibarbata was first found in the Indian Ocean. The new specimen differs from the fishes of the type series in the details of the structure of the escal appendages and the posterior branch of the hyoid barbel. Ontogenetic variability in the structure of the esca of L. pennibarbata is discussed; it has been shown that the length of the distal appendage of the esca and its lateral branches, as well as the number of appendages of the posterior (unpaired) branch of the hyoid barbel in this species are subject to significant individual variability, not related to growth. It was revealed that the previously noted differences in the size and pigmentation of the distal appendages of esca in H. appelii cannot be associated with ontogenetic variability, as was assumed, but indicate the combined nature of this species. The reasons are given for assigning the name H. appelii to a form with short, intensely pigmented (except for the tips) distal appendages.