Published online by Cambridge University Press: 20 May 2016
The fossil record of the volutid gastropod Arctomelon is represented by three species from the Koryak Upland and the Kamchatka Peninsula (Russian northeast), ranging in age from late middle Eocene to early Miocene. Although Recent Arctomelon stearnsii (Dall, 1872) from the northeastern Pacific is a cold-water species, paleontological data point to the origin of the genus in shallow, warm-water conditions that existed in high latitudes of the northwestern Pacific during Paleogene time. The fossil record also indicates survival of the genus during the climatic coolings through the Cenozoic. It is apparent that Arctomelon successfully adapted to the new cooler and deeper-water conditions. Despite this major change of life habit, shell morphology has remained fairly unchanged since the Eocene. Two new species of the genus Arctomelon, A. harasewychi sp. nov. and A. rateginense sp. nov., are described.