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Journal of Paleontology 91(6):1199–1219
specimens that show the range of morphology, including onto- genetic changes in order to avoid potentialmisunderstanding from a form-species approach. Meanwhile, the conodont taxonomy of several Wuchia-
pingian Clarkina species, especially C. postbitteri postbitteri, which is used to define the base of the Wuchiapingian Stage, is still debated. The First Appearance Datum (FAD) of C. postbitteri postbitteri is in Bed 6k at the Penglaitan Section, based on the taxonomy in Mei et al. (1994a) and Henderson et al. (2002). However, Wang et al. (1998), Wang (2000, 2001, 2002), and Wang and Kozur (2007) had a different taxonomic view of some Clarkina species, suggesting that the first occurrence of C. dukouensis, which is the descendant of C. postbitteri postbitteri, occurs in Bed 6k at the Penglaitan Section. In addition, Wang and Dong (1991) described some C. guangyuanensis elements in the Maokou Formation, but this species was established and described from the middle part of the Wuchiaping Formation by Li et al. (1989). Thus, these arguments created issues affecting both the basal Wuchia- pingian Stage identification and the establishment of a high- resolution conodont succession in the Wuchiapingian Stage. In this paper, we review all Wuchiapingian Clarkina
species in South China and figure ontogenetic growth series from juvenile to gerontic individuals for each valid and important species. In doing so, we revise both Wuchiapingian conodont taxonomy and the biostratigraphic succession. The result is a biostratigraphic framework for an interval of stable biodiversity following both a lateGuadalupian extinction (Shen and Shi, 2009; Wang et al., 2014) and the latest Guadalupian lowstand that marked the lowest relative sea level of the Phanerozoic.
Stratigraphy
Most regions in South China have Wuchiapingian deposits, except for three lands (the Kangdian, Yunkai, and Cathaysian lands) and the sedimentary deposits have been referred to several formations. Four of them, the Xuanwei, Lungtan, Wuchiaping, and Heshan formations, are representative (Fig. 1.1). The Xuanwei Formation consists of sandstone, shale, and coal seams containing abundant plant fossils and few marine fossils. It represents terrestrial and/or marine-nonmarine transitional sediments, which are distributed mainly east to the Kangdian Land. The Lungtan Formation is dominated by siltstone, shale, and coal, as well as a few limestone beds that contain rare conodonts and abundant brachiopod and plant fossils. It represents a transitional facies between terrestrial and marginal marine. The Wuchiaping Formation is marked at the base by the Wangpo Shale and comprises siltstone, shale, coal, limonite, and ash beds that represent a deposit associated with the sequence boundary between the Wuchiaping limestone and the Kuhfeng and/or Maokou formations and the related Emeishan Large Igneous Province. The main part of the Wuchiaping Formation is composed of limestone with some cherty nodules or bands and contains abundant brachiopods, the fusulinid Codonofusiella, corals, and bivalves. The Heshan Formation consists of siliceous limestone, limestone, and many cherty nodules or bands interbedded with coal seams that indicate a shallower-water depositional environment than the Wuchiaping Formation. Therefore, the Wuchiaping and Heshan formations have the
optimal successions to establish high-resolution conodont bios- tratigraphy of the Wuchiapingian Stage.
Conodont succession
The first namedWuchiapingian conodont species, Neogondolella (=Clarkina in this paper) liangshanensis, which was established by Wang (1978) in China, was considered as the only marker of the Wuchiapingian conodont biostratigraphy. Wang and Wang (1981) established two assemblage zones, the N. liangshanensis-N. “bitteri” Assemblage Zone and the N. orientalis Assemblage Zone, in the “Wuchiapingian Stage” based on conodonts from the Wuchiaping and Lungtan formations in South China. However, Mei and Wardlaw (1996) considered that liangshanensis and bitteri did not coexist in the same stratigraphic interval so that the “N. liangshanensis-N. bitteri” Assemblage Zone could not be used. Yang et al. (1987) revised these two assemblage zones as the Gondolella (=Clar- kina in this paper) liangshanensis Zone and the Gondolella (=Clarkina in this paper) orientalis Zone, and confirmed G. liangshanensis as a marker of the lower part of the Wuchiaping Formation and G. orientalis as a marker of the upper part of the Wuchiaping Formation. Clark and Wang (1988) identified a few specimens as Mesogondolella rosenkrantzi (their Neogondolella) in the upper part of the Wuchiaping Formation. However, Mei and Henderson (2001) considered M. rosenkrantzi as a marker of the Wuchiapingian only in the North Cool Water Province. Li et al. (1989) added two marker species, Neogondolella (=Clarkina in this paper) leveni and N. guangyuanensis, into the N. liangshanensis-N. bitteri Assemblage Zone. They considered that the upper and lower relationships of the two Wuchiapingian assemblage zones were difficult to determine. Wang and Dong (1991) and Tian (1993a, b) recognized the N. leveni Assemblage Zone between the N. liangshanensis-N. bitteri Assemblage Zone and the N. orientalis Assemblage Zone. Mei et al. (1994a) determined seven Wuchiapingian zones, in ascending order: Clarkina dukouensis, C. asymmetrica, C. leveni, C. guangyuanensis, C. transcaucasica, C. orientalis, and C. inflecta zones. In addition, Mei et al. (1994b) and Mei and Wardlaw (1996) considered that specimens identified as N. “bitteri” by Wang and Wang (1981) have a very different mophology from those of North America and established the species Clarkina post- bitteri. Thus, the C. postbitteri Zone, which was considered as the first zone of the Wuchiapingian, was added below the C. dukouensis Zone by Mei et al. (1994b). Henderson et al. (2002) named a new subspecies, C. postbitteri hongshuiensis, which is considered as the topmost conodont zone of the Capitanian (Guadalupian), making theC. postbitteri postbitteri zone as the first zone of the Wuchiapingian. The Wuchiapingian cono- dont succession now includes the Clarkina postbitteri postbitteri, C. dukouensis, C. asymmetrica, C. leveni, C. guangyuanensis, C. transcaucasica, C. orientalis,and C. longicuspidata zones (Henderson, 2017) in the latest Permian timescale (Fig. 2).
Clarkina postbitteri postbitteri Zone.—This zone is definedbythe first occurrence of Clarkina postbitteri postbitteri at the base and
by the first occurrence ofC. dukouensis at the top, and is restricted to the upper part of the original C. postbitteri Zone established
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