Argyropelecus bullockii
Upper Miocene
Monterey Formation
Santa Barbara County, California, USA

55mm hatchetfish on 143mm slab.

Here is a specimen of a Pacific Ocean species that has recently come on the market.  The article below reviews a fish fauna from a number of sites in Poland with an Atlantic deepwater hatchetfish species, A. cosmovicii, discussed in detail.

Jerzmanska, A. N. N. A. (1968).  Ichthyofaune des couches à ménilite (Flysch des Karpathes). Acta Palaeontologica Polonica, 13, 379-481.