Jeletzkytes nebracensis
Fox Hills Formation Timber Lake Mbr.
Upper Cretaceous (Maastrichtian)
Dewey County, South Dakota

Here is classic specimen of a complete Jeletzkytes nebrascensis. The shell on the living chamber has excellent iridescence of red and green. The suture pattern is visible through thin shell on the inner whorls. This is the macroconch form. The specimen is prepared in its original matrix. It has been repaired. The ammonite is 5 inches across. This is a classic example from the locality.
The macroconch of this species is compressed and the last whorl is markedly higher than wide. The phragmocone is conspicuously tuberculate with strong ventrolateral tubercles and five to seven rows of weaker flank tubercles which commonly extend onto part or all of the body chamber. The microconch is variably tuberculate commonly with double row of umbilical tubercles or bullae.
The Timber Lake Member of the Fox Hills Formation represents a sandy barrier-bar complex near the top of the Fox Hills Formation. It contains a highly fossiliferous assemblage zone.