Li Guoxiang (李国祥)

Early Cambrian eodiscoid trilobites of the Yangtze Platform and their stratigraphic implications

Analysis of the taxonomy and stratigraphic distribution of the Early Cambrian eodiscoid trilobites of the Yangtze Platform indicates that species of Tsunyidiscus and Hupeidiscus can be used for biostratigraphic correlation. T. aclis occurs only in the lower Qiongzhusian, T. armatus occurs in the lower and middle Qiongzhusian, while T. niutitangensis and T. tingi occur mainly in the middle and upper Qiongzhusian, with only T. tingi extending upward into the lower Canglangpuian. H. orientalis first appears in the upper Qiongzhusian, reaching peak abundance in the lower Canglangpuian and becoming extinct above the Drepanuroides Zone. Biostratigraphic and lithostratigraphic correlations indicate that the limestone in the lower part of the Mingxinsi Formation, the Upper Member of Jiumenchong Formation, and the upper part of the Middle Member of the Huangbailing Formation, can be correlated with each other as Hupediscus, an index fossil of the lower Canglangpuian, is abundant in all these units. The lower part of the Niutitang and Jiumenchong formations in eastern Guizhou, which mainly represent Qiongzhusian strata, can be correlated with the Lower Member of the Huangbailing Formation. The basal part of the Niutitang Formation, which may be equivalent to the Upper Meishucunian Shiyantou Formation in eastern Yunnan, is very condensed. Well-preserved sponge faunas and non-mineralized fossils in the lower part of the Niutitang and Hetang formations are not older than Qiongzhusian in age.

Early Cambrian protoconodonts and conodont-like fossils from China: Taxonomic revisions and stratigraphic implications

Abstract Protoconodonts and conodont-like microfossils are characteristic components in the early Cambrian skeletal faunas. Sincethe 1970s, these tooth-like phosphatic sclerite fossils have been widely recovered from the Lower Cambrian of China, and altogether 25 genera and 52 species of protoconodonts and conodont-like fossils have been described, although some taxa represent synonyms or invalid taxonomic names, and some assignments are apparently inappropriate. Through a brief review and discussion, the distinction between protoconodonts and conodont-like fossils is denoted here. Thereare 13 genera previously assigned to protoconodonts in the literature, but present taxonomic revisions show that 5 of them are junior synonyms of other taxa, and 2 represent unknown arthropods. The other 12 genera, of which 5 also are junior synonyms, only reveal a conodont-like morphology with various zoological affinities: most of them are enigmatic, and only Beshtashella and Parafomitchella (=Beshtashella) can be assign...

SPHENOTHALLUS FROM THE LOWER SILURIAN OF CHINA

The genus Sphenothallus was erected by Hall (1847, p. 261), who originally considered it a land plant. Sphenothallus was later classified as a marine invertebrate. Moore and Harrington (1956, p. F65) regarded Sphenothallus as a hydrozoan or scyphozoan. Van Iten et al. (1992, p. 139) supported Moore and Harringtons idea, and argued that it displays a close relationship to conularids (also see Li, 2000, p. 91). However, Mason and Yochelson (1985, p. 93–94) suggested that Sphenothallus is an annelid or “worm” (also see Fauchald et al., 1986, p. 64; Feldmann et al., 1986, p. 344–345; Choi, 1990, p. 403; Bartels et al., 1998, p. 114–117). The exact phylogenetic affinity of Sphenothallus is still debated. Sphenothallus has been recognized in Paleozoic rocks ranging from Cambrian to Permian, at numerous localities in the northern and southern hemispheres (Van Iten et al., 1992, p. 136; Neal and Hannibal, 2000, p. 369; Li, 2000, p. 88, 89; Baird and Brett, 2002, p. 208). Up until now, few reports of sphenothallids have been published from the Silurian. Murchison (1839) reported two sphenothallids from the Silurian of Scotland. Billings (1862) described one sphenothallid: Serpulites dissolutus Billings (pl. 1.1, figs. 6, 7) from the Lower Silurian; however, Bolton (1994, p. 4) considered the geological age of specimens, classified as Sphenothallus angustifolius , to be Middle Ordovician. Brood (1988, p. 83) published sphenothallid phosphatic tubes from the Ludlow rocks of Gotland under the generic name Campylites . In China, Sphenothallus has been solely reported from the Cambrian only at two localities: Taijiang, Guizhou (Zhu et al., 2000, p. 229–234) and Nanzheng, Shaanxi (Li, 2000, p. 93). The purpose of the present paper is to describe Sphenothallus angustifolius Hall based on …