Capitanian (Middle Permian) Radiolarians from the Patterson Hills Sections of the Reef Trail Member of the Bell Canyon Formation, Guadalupe Mountains, West Texas

Radiolarians recovered from several intervals in two sections of the Reef Trail Member of the Bell Canyon Formation located in the Patterson Hills of Guadalupe Mountains National Park comprise a biostratigraphically significant and diverse assemblage with at least 45 species including 21 new taxa. The Reef Trail Member is a basinal marine carbonate/clastic unit that represents latest Guadalupian deposition in the Delaware Basin. This assemblage is significant because it contains new species of Pseudoalbaillella, a biostratigraphically significant component of any Guadalupian assemblage, which may be useful in regional correlation in the Delaware Basin area. It is not known if the new species of Pseudoalbaillella, will be useful for global correlation as they have not been recognized in Guadalupian age strata elsewhere. The radiolarian assemblage also contains the oldest known appearance of Albaillella yamakitai, which is reported only above the Guadalupian-Lopingian boundary in China and Japan. Sixteen species of Latentifistularia are described including 5 new species. The biostratigraphic significance of Latentifistularia has been underestimated in Permian strata and these taxa are useful for global and regional correlation. Nineteen species of Spumellaria and Entactinaria are described, thirteen of which are new. Most radiolarian studies do not include descriptions of the spherical radiolarian component so the stratigraphic ranges of many species are not known. Describing and documenting the Entactinaria and Spumellaria in the Reef Trail Member will help establish if any of these new species may be useful in regional and/or global correlation. Many of the taxa found in the Patterson Hills sections occur in coeval strata in the Apache Mountains located in the southern part of the Delaware Basin. The cause of faunal variability between the Guadalupe and Apache mountains requires further investigation. It is hypothesized that variations within the assemblages may be a result of localized paleoenvironmental fluctuations.