Microvertebrates from the Silurian–Devonian boundary beds of the Eastport Formation, Maine, eastern USA

Abstract

Agnathan and gnathostome remains, associated with lingulid brachiopod fragments and distinctive ostracods, have been extracted from a small calcareous mudstone sample collected from the type section of the Eastport Formation on the northern shore of Moose Island, Maine. The vertebrate assemblage includes osteostracan, anaspid, and thelodont scales, and acanthodian scales, spines and teeth, which support a late Pridoli, or possibly earliest Lochkovian, age for the stratum. The thelodont Paralogania denisoni n. sp. is described, associated with a single thelodont scale referred tentatively to Talivalia? sp. indet., and acanthodians Nostolepis striata, Gomphonchus sandelensis, and Poracanthodes punctatus in a fauna that shows similarities to late Pridoli assemblages in Britain, parts of Europe, Russia, Greenland, and arctic Canada.

Keywords:

• Thelodonti,
• Acanthodii,
• paleobiogeography,
• Avalonia,
• biostratigraphy