Third species of Eusthenodon (Tetrapodomorpha, Tristichopteridae) from the Upper Devonian (Famennian) Catskill Formation of Pennsylvania, U.S.A., and an inventory of additional tristichopterid fossils from the type locality

We describe a new species of tristichopterid from a roadcut exposure of the Upper Devonian (Famennian) Catskill Formation at the Cogan House Exit Ramp locality in Lycoming County, Pennsylvania, U.S.A. Eusthenodon mesingw, sp. nov. is represented by two partial skulls, a cleithrum associated with one, and a lower jaw associated with the other. The new species belongs to a different (larger) size category than Eusthenodon bourdoni, the other tristichopterid species at the Cogan House Exit Ramp site; it also differs by the presence of a spike-shaped process of the rostral parietal margin, a notch in the dorsocaudal corner of the postorbital, and by the lack of vertical labial laminae on coronoids 1 and 2. It is the sixth tristichopterid species to be described from the Catskill Formation and the first instance of two tristichopterid species at a single Catskill Formation locality. Because there are at least two tristichopterids at the Cogan House Exit Ramp site, we hesitate to give specific taxonomic assignments to other newly collected, isolated fossils from the locality that compare favorably with the condition in Tristichopteridae but are otherwise without diagnostic anatomy. We report on those fossils here, with limited description and figuring, as a way of presenting the complete inventory of potential tristichopterid fossils that represent the recent collecting efforts at the Cogan House Exit Ramp locality.