New palynomorphs from the Ordovician-Silurian boundary interval: Eastern North America and Saudi Arabia

A distinctive coenobial palynomorph, Speculaforma gen. nov., and its two new species, S. delicata and S. elongata, are described from the Llandovery Grimsby Formation, Medina Group, from New York and are part of a more diverse palynomorph assemblage. Speculaforma delicata was also recovered from the Tuscarora Formation, West Virginia, and subsurface Hirnantian sediments in southern Saudi Arabia. Speculaforma is questionably assigned to the Hydrodictyaceae within the order Chlorococcales based on its geometrically regular coenobia. It is considered to be a freshwater or brackish-water alga. Occurring with this coenobium are two new acritarchs, Lunataforma parallela gen. et sp. nov. and Pertusidisca quadripora gen. et sp. nov. These acritarchs have been recovered from near-shore marine settings, in both North America and Saudi Arabia; but in North America Lunataforma was also recovered from sediments considered to represent an open marine environment.