Pityostrobusmillerisp. nov., a pinaceous cone from the Lower Cretaceous (Aptian) of southwestern Russia

Abstract

A new species of permineralized Pityostrobus cone, Pityostrobus milleri Falder et al., sp. nov. has been discovered in a calcareous nodule from shallow marine sediments of Early Cretaceous (latest Aptian; Clansenian) age in the Caucasus Mountains in southwestern Russia. Nodules of this type also contain wood fragments, gastropods, bivalves, and an extremely rich assemblage of well preserved cephalopods. Russian spore and pollen analyses indicate that deposition in this region may have occurred during a temperate climate regime. The cone is cylindrical, about 2.5 cm in diameter and individual scales contain up to 17 resin canals and 18 vascular strands. Although the fossil displays many features of modern Pinus cones, including inflated scale apexes, resin canals abaxial to vascular tissue in scale base, and scale strands curved on the adaxial side, it cannot be assigned to Pinus because the bract and scale trace are not united at their origin. Tunneled borings in the cortex of the cone axis are tightly packed with frass, and resemble tunnels of modern cone boring beetles such as Conophthorus. This cone further documents the worldwide diversity of pinaceous conifers during the Cretaceous, and demonstrates a well developed syndrome of insect herbivory in the Pinaceae by the late Mesozoic.