Yeh Kuei-yu (2011) A Middle Jurassic (upper Bajocian) Radiolarian Assemblage from Snowshoe Formation, east-central Oregon // Collection and Research. Vol.24. P.1-77.
This is the second in a series of studies dealing with the whole fauna taxonomic studies of Middle Jurassic radiolarian assemblages from the Snowshoe Formation, east-central Oregon. All the studied specimens were obtained from a limestone nodule (with locality number OR549B). Totally 126 forms were identified and assigned respectively to 26 families and 46 genera. Among them 19 new species, one new genus (Barbuta Yeh) and one new family ( Barbutidae Yeh) are described. The studied assemblage is moderately high in diversity. It is characterized by the abundant occurrence of Emiluvia brevispina Yeh, n. sp., Emiluvia meganodosa Yeh, n. sp., Emiluvia parvinodosa Yeh, n. sp., Hiscocapsa minuta Yeh, n. sp., Hsuum lupherium Pessagno and Whalen, Hsuum parasolense Pessagno and Whalen, Hsuum robustum Pessagno and Whalen, Leugeo parvispina Hull, Perispyridium facetum Pessagno and Blome, Perispyridium tamarackense Pessagno and Blome, Praeparvicingula burnsensis (Pessagno and Whalen), Praeparvicingula grantensis (Pessagno and Whalen) and Praeparvicingula sodaensis (Pessagno and Whalen). The forms with large size tests and muticyrtid nassellarians with skirt-like structure at final post-abdominal chamber are found completely absent in the studied fauna. The results of this study are not only helpful to understand the Middle Jurassic radiolarian faunas from North America, but also providing useful information to establish the Middle Jurassic biostratigraphic zonal scheme and to do future studies on global faunal comparison.