Key conodonts from the Tieqiao and Penglaitan Sections. All specimens are SEM photos magnified the same amount (for scale specimen 9 is exactly 1 mm in length). Letters a and b designate different views of the same specimen. 1, 6-10, 13-16, Clarkina postbitteri hongshuiensis Henderson et al., 2002 showing the specimens with closely spaced and often fused denticles, especially in adult specimens. Specimens 1, 6, 8, 13-16 are from Bed 6i-upper and 7, 9, 10 are from Bed 6j at the Penglaitan Section. 2-5, Clarkina postbitteri postbitteri Mei and Wardlaw in Mei et al., 1994a showing the specimens with more widely spaced and consistently discrete denticles and abruptly narrowing anterior (top in figure) platform. All specimens are from Bed 6k at the Penglaitan Section. 11-12, Jinogondolella granti Mei and Wardlaw in Mei et al., 1994a from Bed 6h at the Tieqiao Section.