Yuan et al.—Permian conodont taxonomy and biostratigraphy in South China
Remarks.—Clarkina postbitteri hongshuiensis is different from species of Jinogondolella by having fused anterior denticles forming a free blade and the lack of serration in the anterior part of the platform. It should be differentiated from J. granti and Clarkina postbitteri postbitteri by comparing separate popula- tions (see Henderson et al., 2002 for detail). Henderson et al. (2002) divided Clarkina postbitteri into two
subspecies, C. p. hongshuiensis and C. p. postbitteri, therefore some specimens of C. postbitteri in Mei et al. (1998a) and Wang (2000) with the same characteristics as in C. p. hongshuiensis should be identified as C. p. hongshuiensis. Sun and Xia (2006) recognized someC. p. hongshuiensis in theDachongling Section, and few specimens are similar to C. p. hongshuiensis. However, they are difficult to identify because they are broken and unclear. Zhang et al. (2008) also recognized many C. p. hongshuiensis in the Maoershan Section. However, almost all individuals have serrations so that they should be assigned to Jinogondolella. Clarkina postbitteri hongshuiensis was elevated to a
species level, Clarkina hongshuiensis, by Lambert et al. (2010) and Wardlaw and Nestell (2010). However, it has a very short interval at the Penglaitan Section and cannot be found at any other sections so far. Therefore, it is still considered to be a subspecies in this paper.
Clarkina postbitteri postbitteri Mei and Wardlaw in Mei et al., 1994b Figure 4.1–4.17
1994b Clarkina postbitteri Mei and Wardlaw in Mei et al., p. 229, pl. 1, figs. 3–6, pl. 2, figs. 7–11. Clarkina postbitteri; Kozur, pl. 5, fig. 26.
1995 1996
?2000 Clarkina longicuspidata; Wang, pl. 6, figs.1, 2. 2002
2000 2000
1998a Clarkina postbitteri; Mei et al., p. 61, pl. 4, figs. 1–3, 9–11, pl. 5, figs. 2–4, pl. 8, figs. 1–9. Clarkina postbitteri; Wang, pl. 1, figs.1–8. Clarkina dukouensis; Wang, pl. 2, figs.1–8.
Clarkina postbitteri; Mei and Wardlaw, pl. 17.1, figs. 16, 18–25.
2006a Clarkina postbitteri postbitteri; Jin et al., figs. 7.2–7.5.
Clarkina postbitteri postbitteri; Henderson et al., p. 730, pl. 2, figs. 1–7.
Holotype.—NIGP123476, from the Maokou Formation, Guangxi Province, China (Mei et al., 1994b, pl. 1, fig. 6).
Original diagnosis.—A species of Clarkina characterized by a P1 element that has a rounded posterior termination, a small brim, a relatively long and narrow platform that is widest in the anterior half just posterior to the anterior narrowing where the platform is mildly upturned (except for some large forms, which may be widest near the posterior termination), posterior sides of platform are roughly parallel with a slight indentation on the posterior inner side, a moderate cusp of circular to elongate-oval cross section, space between cusp and first posterior denticle is larger than any other on carina, first three or four denticles more widely spaced and less fused than anterior denticles, furrows narrow and well developed, platform margins mildly upturned, anterior narrowing of platform in anterior third to fourth of specimen (Mei et al., 1994b, p. 229).
1207
Emended diagnosis.—A subspecies of C. postbitteri character- ized by a P1 element with a symmetrical, relatively long and narrow platform whose widest point is in the middle part, nar- rowing gradually both anteriorly and posteriorly, or with lateral margins that are nearly parallel. Platform is abrupt, narrowing in the anterior 1/3 to 1/4 of the element. Posterior end of platform is rounded and usually has a narrow brim, except for juveniles. Moderate cusp is erect (adults) to slightly reclined (juveniles), terminal, slightly higher and larger than the posterior denticles. Denticles are more discrete in most individuals whereas in gerontic forms they are more closely spaced. Posterior 3–4 denticles usually nearly equal in height and more widely spaced than anterior denticles. Gap between the cusp and the posteriormost denticle is obvious and larger than any other gap on carina. Furrows are moderate, smooth, and well developed.
were identified as Clarkina dukouensis by Wang (2000), but were referred to C. postbitteri postbitteri by Henderson (2002), whose viewpoint is accepted in this paper because those specimens gradually narrow in the anterior 1/3 and have more discrete denticles (see Wang, 2000, pl. 2, figs. 4, 5), which are characteristics that belong to the earliest Clarkina populations. Some juveniles identified as C. longicuspidata by Wang (2000) may be referred to C. postbitteri postbitteri based on adult specimens, which coexisted with those juveniles. The three C. postbitteri postbitteri specimens that were recognized in the Dacongling Section by Sun and Xia (2006) are difficult to verify. Zhang et al. (2008) recognized a C. postbitteri postbitteri range that is from the GLB interval to the C. guangyuanensis Zone. However, the morphotypes of those specimens are variable and they should be referred to several other species.
Remarks.—Clarkina postbitteri postbitteri is usually dis- tinguished from C. postbitteri hongshuiensis by much more discrete denticles and abrupt narrowing of the platform in the anterior 1/3. Some specimens from Bed 6k at the Penglaitan Section
Clarkina dukouensis Mei and Wardlaw in Mei et al., 1994a Figure 4.18–4.31
1994a Clarkina dukouensis Mei and Wardlaw, p. 134, pl. 1, figs. 18, 19.
1994c Clarkina liangshanensis?; Mei et al., pl. 3, fig. 11. 1995
1998a Clarkina dukouensis; Mei et al., pl. 5, figs. 8, 9, pl. 8, figs. 10–19, pl. 10, figs. 1–4.
Clarkina dukouensis; Kozur, pl. 5, fig. 25.
2000 2000 2000
2002 2006 2008
2010
Clarkina dukouensis; Wang, pl. 2, figs. 9–15. Clarkina penglaitanensis Wang, pl. 4, figs. 11–13.
Clarkina niuzhuangensis; Wang, pl. 6, figs. 13, 14, 17, 18.
Clarkina dukouensis; Henderson et al., p. 729. Clarkina dukouensis; Sun and Xia, pl. 1, figs. 14–16. Clarkina dukouensis; Zhang et al., pl. 2, figs. 7, 8, 16.
?2008 Clarkina postbitteri hongshuiensis; Zhang et al., pl. 2, fig. 10.
Clarkina dukouensis; Shen and Mei, p. 153, figs. 3.1a– 3.7b.
1994b Clarkina dukouensis; Mei et al., pl. 1, figs. 1, 2, pl. 2, figs. 1–6, 12, 13.
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