PHYLLOLEPID PLACODERMS FROM THE CATSKILL FORMATION (LATEST DEVONIAN) AT RED HILL, PENNSYLVANIA -- PRELIMINARY RESULTS

Phyllolepids were mid-Paleozoic placoderm fishes, most closely allied to arthrodires, and found at scattered locations around the world, but until now not known from Canada or the U.S. (with the exception of two isolated nondescript bone fragments).

Red Hill is a large roadcut on PA Hwy. 120 3.6-4.2 mi (5.8-6.8 km) east of the junction of PA Hwys. 120 and 144 (southbound) in Renovo. Red and green mudstones and sandstones yield a diverse freshwater fish fauna, including phyllolepid fragments, from the Duncannon Member of the Catskill Formation, of Late Famennian (Latest Devonian) age.

One nearly complete fish apparently represents a new species of Phyllolepis, and is characterized by: 1) nuchal plates having numerous pits and tubercles on the anterior portion, combined with fluted or projecting corners where the antero-lateral and postero-lateral margins join; and 2) anterior ventro-lateral plates with an exaggerated, forward-extending point on the antero-medial corner. Additionally, 2 isolated nuchals and 5 anterior ventro-laterals in our collection belong to this species.

The remaining specimens are dissociated isolated bones exhibiting subtle but consistent differences recognizable as previously described Phyllolepis species: Ph. concentrica (1 anterior ventro-lateral), Ph. nielseni (1 paranuchal; 2, possibly 4, antero-laterals; 3 anterior ventro-laterals), Ph. undulata (1 nuchal; 6 median dorsals), and Ph. woodwardi (2 nuchals). These species have been reported from Greenland, Scotland, and Belgium, all on the Devonian Old Red Sandstone Supercontinent, but separated from Gondwana (including Australia). Having several related species in the same deposit calls to mind modern lakes in which several centrarchid species regularly co-occur. Alternative interpretation as a single variable phyllolepid species would require intergrading morphologies, thus far not observed here.