Protopanderodus gradatus Serpagli, 1974

Zhen, Yong Yi & Nicoll, Robert S., 2009, Biogeographic and Biostratigraphic Implications of the Serratognathus bilobatus Fauna (Conodonta) from the Emanuel Formation (Early Ordovician) of the Canning Basin, Western Australia, Records of the Australian Museum 61 (1), pp. 1-30 : 16

Protopanderodus gradatus Serpagli, 1974

Fig. 9A–P

Protopanderodus gradatus Serpagli, 1974: 75 , pl. 15, figs 5a–8b, pl. 26, figs 11–15, pl. 30, figs 1a–b; text-fig. 17; Zhen et al., 2004: 56–57, pl. 5, figs 1–10 (cum syn.); Zhen & Percival, 2006: fig. 9A–C; Zhen et al., in press a: fig. 8A–Q.

Material. 126 specimens from two samples ( Table 1).

Remarks. Protopanderodus gradatus is common in one (WCB705/243) of the samples studied from the Emanuel Formation. This material is identical with the types described from the San Juan Formation (Early Ordovician) of Argentine Precordillera ( Serpagli, 1974), and those recently documented from the Honghuayuan Formation of Guizhou, South China (Zhen et al., in press a, fig. 8A–Q). An additional element ( Fig. 9J–P ) bearing a more compressed cusp and a less extended base with a rounded basal margin has also been recognized in the Emanuel material. It also shows rather prominent striation in the area immediately anterior to the lateral costa, and a weakly developed chevron-shaped pattern of striae adjacent to the anterior margin ( Fig. 9K, O ). As these distinctive characters are not observed in the other elements of P. gradatus , it is tentatively assigned herein to the M position of P. gradatus . Some specimens bear rounded holes of about 3–4.5 µm in diameter, presumably representing the boring structure made by an unknown organism ( Fig. 9O, P ).

Figures

Fig. 9. Protopanderodus gradatus Serpagli, 1974. All from sample WCB705/243. A–C, Sa element; (A), CPC39869, lateral view (IY128-010); (B), CPC39870, lateral view (IY128-011); (C), CPC39871, basal view (IY128-008). D–G, Sc element; (D), CPC39872, inner lateral view (IY128-001); (E), CPC39873, inner lateral view (IY128-002); (F), CPC39874, basal-inner lateral view (IY128-005); (G), CPC39875, upper-inner lateral view (IY128-009). H,I, P element, CPC39876, (H), inner lateral view (IY128-019); (I), basal-outer lateral view (IY128-020).J–P,?M element; J–K, CPC39877, (J), inner lateral view (IY129-037); (K), close-up inner lateral view, showing striae near the furrow and chevron-shaped pattern of striae adjacent to anterior margin (IY129-038); L,M, CPC39878, (L), outer lateral view (IY129-041); (M), anterior view (IY129-039); N–P, CPC39879, (N), inner lateral view (IY129-042); (O), close-up inner lateral view, showing striae near the furrow and chevron-shaped pattern of striae adjacent to anterior margin (IY129-043); (P), close up showing rounded boring hole on the surface (IY129-044). Scale bars 100 µm unless otherwise indicated.