LATE PENNSYLVANIAN FISHES FROM THE FINIS SHALE OF NORTH-CENTRAL TEXAS

The fossil-rich deposits from the Finis Shale (Graham Formation) at the "spillway section" near Jacksboro (North-Central Texas) are dated as early Virgilian (early Gzhelian; Late Pennsylvanian) in age. The Finis Shale is part of a cyclothem and represents the shallowing upwards sequence at this outcrop. The shale deposits are capped by phylloid algae and fusulinid carbonates of the Jacksboro Limestone. Various chondrichthyan macroremains such as Glikmanius, Orodus, Campyloprion, or Petalodus are known from these deposits.

A diverse assemblage of fish microremains is now discovered in and described from the Finis Shale deposits. The micro-fossil assemblage includes numerous chondrichthyan teeth and scales, while acanthodian scales and actinopterygian teeth and scales are rare. The chondrichthyan microremains are taxonomically more diverse and represented by teeth of the bransonelliform Bransonella nebraskensis Johnson, by the symmoriiform Denaea cf. williamsi Ginter et Hansen, and yet undetermined stethacanthids. The ctenacanthiforms Heslerodus divergens (Trautschold) and Glikmanius sp., sphenacanthid euselachians, the neoselachian Cooleyella amazonensis Duffin, Richter et Neis, the petalodontids Euglossodus sp. and cf. Tanaodus sp., and eugeneodontid remains are also preserved. Symmoriiform denticles and chondrichthyan scales of various types are also found. The new occurrence of fishes demonstrates the presence of chondrichthyan taxa with different food specialization in the early Virgilian faunal community.