Lower and Middle Ordovician conodont diversity of the Yichang Region, Hubei Province, Central China

Abstract

A survey on the (palaeo-) diversity of the Lower and Middle Ordovician conodont faunas from the Yichang Region, Hubei Province, Central China is presented. Analysis of the number of species through time shows the species richness is cyclical developed in the succession -varying from low to high. One major conodont diversity peak is recorded in the mid to late Floian Stage (Oepikodus evae Zone, stage slice Fl 2, Lower Ordovician), where 33 species are recorded in the lower unit of the Dawan Formation. A smaller but second high diversity is found in the Darriwilian Stage (Lenodus variabilis Zone; stage slice Da 2, Middle Ordovician) with a maximum of 23 species. Secondary, smaller diversification maxima are present in the early Tremadocian, late Tremadocian, early Dapingian and late Darriwilian stages. Current information on acritarchs, brachiopods, and trilobites shows that the highest diversity maximum of conodonts corresponds to a similar high in brachiopod diversity, whereas acritarch and trilobite maximum diversity appear after the conodonts/brachiopods in the region.•

A New Middle Ordovician Conodont Fauna from the Thong Pha Phum Area of Western Thailand

“…E. suecicus is associated with Periodon cf. aculeatus Hadding, 1913 and Baltoniodus prevariabilis (Fåhraeus, 1966;Wu et al, 2010). Although P. lunnensis has not previously been reported in China, the existence of E. suecicus suggests that the study section is comparable to the E. suecicus Zone in South China.…”

“…An, 1987;Wang et al, 1996;Zhang, 1998b;Wu et al, 2010). Wu et al (2010) proposed the Lenodus antivariabilis, Lenodus variabilis, Yangtzeplacognathus crassus, Dzikodus tablepointensis, E. suecicus, and Y. foliaceus zones, in ascending order ( Figure 3). The base and top of the E. suecicus Zone correspond to the first appearances of E. suecicus and Y. foliaceus, respectively.…”

“…Bergström, 1971Bergström, , 1983Lindström, 1971;Dzik, 1976Dzik, , 1994Löfgren, 1978Löfgren, , 1994Löfgren, , 2000Bagnoli and Stouge, 1997;Zhang, 1998b;Rasmussen, 2001;Viira et al, 2001) and the Darriwilian strata in South China (e.g. An, 1987;Zhang, 1998b;Wu et al, 2010). Bergström (1971) suggested that the E. suecicus …”

An Early Ordovician clonal organism from China with a zig-zagged suture on branches

“…It consists mainly of dark grey to grey skeletal and peloidal limestone interstratified with greenish grey shale. The age of the Fenxiang Formation originally was interpreted as late Tremadocian (e.g., Wu et al 2010). However, the occurrence of the conodont Acodus triangularis in Bed 13 at Tianjialing indicates that at least the upper part of the formation is early Floian (Arenig) in age (Zhen et al 2009, Baliński et al 2012.…”

Early Ordovician black corals from China

“…The formation is about 20 m thick in the west side of the anticline and can reach over 50 m in the east side. Although until recently the Fenxiang Formation was regarded as Tremadocian in age (e.g., Zhan & Jin 2007, Wu et al 2010, Adachi et al 2011, latest data on conodont fauna from the formation indicate that at least its upper part represents early Floian (Arenig in British terms; Serratognathus diversus Zone; about 477 Ma) (Baliński et al 2012).…”