Findings of the Silver Lightfish Phosichthys argenteus (Phosichthyidae) at the Pulkovo Ridge (South-Central Pacific)

Abstract—The findings of the silver lightfish Phosichthys argenteus at the Pulkovo Ridge (43°–45° S 155°–160° W) are documented. This is the easternmost margin of the species range in the Pacific Ocean. The morphological characteristics of Ph. argenteus are given with a more detailed description of the axial skeleton of the fish. The topography of homodynamic series of the intermuscular bones is specified, and a complex structure of the urostyle, including three autogenous ural centers, is revealed. The comparative morphological analysis did not show any significant differences between the silver lightfish from different parts of the range (New Zealand, Mill Rise, western coast of South Africa, and eastern coast of South America). It is assumed that Ph. argenteus can serve as an indicator species of the notal zone in the open waters of the South Pacific.