The Guluoping section and the understanding of the Stimulograptus sedgwickii graptolite Biozone on the South China Platform (Yangtze Platform)

The uppermost Aeronian (Llandovery, Lower Silurian) Stimulograptus sedgwickii Biozone, as found in the Guluoping section, Hubei Province, China, and its correlation are discussed. This interval has rarely been recognized in China. The differentiation into the Stimulograptus sedgwickii Biozone and the Stimulograptus halli Biozone, recognized in several regions, is problematic and thus is not used in South China. Stimulograptus sedgwickii , Lituigraptus urceolus , and Parapetalolithus praecedens are among the most common and indicative species for the biostratigraphic interval in the Guluoping section. The graptolite fauna can be referred to the higher part of the Stimulograptus sedgwickii Biozone, but not to the top of the interval. A moderately diverse fauna of biserial and uniserial (monograptid) axonophoran graptolites is described and illustrated. The graptolites are associated with a number of small, possibly lyssacinosidan hexactinellid sponges (?Rossellidae) and remains of indeterminate phosphatic brachiopods. The tectonic deformation makes some graptolite identifications difficult, but new taxa have not been noted.