GUADALUPIAN (MIDDLE PERMIAN) AMMONOIDS FROM THE APACHE MOUNTAINS, CULBERSON COUNTY, WEST TEXAS

This is the first comprehensive report of Guadalupian (Middle Permian Series) ammonoids from the Apache Mountains, in Culberson County, Texas. More than 175 specimens from several different localities were studied. These specimens represent forms well known from the Guadalupe and Glass mountains, including Altudoceras altudense, Roadoceras roadense, Paraceltites hoeferi, Cibolites africanus, and Mexicoceras guadalupense. A single involute steinkern was recovered that most likely represents a species of Thalassoceras. Several poorly preserved globular to subspherical fragments may also represent additional cyclolobids.

Prior to this report, only Early Guadalupian (Roadian Stage) ammonoids have been recorded from the Apache Mountains, and none have been figured. Approximately thirty specimens of Paraceltites elegans were mentioned by Spinosa et al. (1975), and specimens of P. elegans, Stenolobulities aff. S. stenoloubulus, and a specimen of Texoceras texanum, were mentioned by Lambert et al. (2000) from the same general locality. This report adds specimens known from the latest Middle Guadalupian (Wordian Stage) and early Late Guadalupian (Capitanian Stage). Both the Roadian and Wordian occurrences of Paraceltites include abundant, nearly monospecific localities from thin beds, which may represent mass mortality after spawning. The other ammonoid localities are in more typical strata that contain a mixed diversity of taxa.