Neospathodus dieneri Sweet, 1970

Leu, Marc, Bucher, Hugo, Vennemann, Torsten, Bagherpour, Borhan, Ji, Cheng, Brosse, Morgane & Goudemand, Nicolas, 2022, A Unitary Association-based conodont biozonation of the Smithian-Spathian boundary (Early Triassic) and associated biotic crisis from South China, Swiss Journal of Palaeontology (19) 141 (1), pp. 1-61 : 21-23

Neospathodus dieneri Sweet, 1970

Fig. 14H

1982 Neospathodus dieneri Sweet ; Matsuda 1982, p. 90, pl. 2, figs. 1–11.

1982 Neospathodus dieneri Sweet ; Koike, p. 37, pl. 6, figs. 15–21.

1984 Neospathodus dieneri Sweet ; Dagis, p. 27, pl. 6, figs. 4–7.

1991 Neospathodus dieneri Sweet ; Beyers & Orchard, pl. 5, fig. 4.

2007 Neospathodus dieneri Sweet ; Orchard & Krystyn, p. 33, figs. 3, 6, 7.

2007 Neospathodus dieneri Sweet ; Zhao & Orchard in Zhao et al., p. 35, pl. 1, figs. 9A–C, 12A–B.

2009 Neospathodus dieneri Sweet ; Igo in Shigeta et al., p. 186, figs. 151.6–151.16, 152.8 (only).

2009 Neospathodus dieneri Sweet ; Orchard & Zonneveld., pp. 782–784, fig. 14, parts 1–4.

2016 Neospathodus dieneri Sweet ; Maekawa et al., p. 199, figs. 4.8–4.10.

2018 Neospathodus dieneri Sweet ; Maekawa in Maekawa et al., pp. 25–28, figs. 15.8–15.9, 15.12–15.14, 15.18– 15.19, 15.21–15.28 (only).

Material. ca. 40 specimens.

Diagnosis. See Sweet (1970), pp. 249–251. Te basal cavity is symmetrically rounded with a circular outline. Te posterior margin is upturned. Te denticles are round (subcircular in cross-section) with a pointy end, discrete and slightly recurved posteriorly. Basal groove runs from the basal pit to the anterior end.

Remarks. Zhao et al. (2007) distinguished three morphotypes of Neospathodus dieneri on the basis of the length of the terminal cusp relative to the other denticles. Teir illustrated morphotype 3 ( Zhao et al., 2007, Fig. 11A–C ) however does not, in our opinion, belongs to N. ex gr. dieneri but is more closely related to N. cristagalli on the basis of its laterally flattened denticles and S-shaped posterior margin. Maekawa and Igo (2014, in Shigeta et al., 2014) assigned specimens to N. dieneri which is laterally flattened, blade-shaped denticles look very different from the holotype. Tey may instead belong to another species or even to another genus (possibly to Discretella ?).

Occurrence. Tis species has been reported worldwide from the Dienerian and early Smithian. Tis includes South China ( Zhao et al., 2007 and this study), Malaysia ( Koike, 1982), the Northern Indian margin ( Matsuda, 1982; Sweet, 1970), South Primorye in Russia ( Shigeta et al., 2009), Canada ( Beyers & Orchard, 1991) and Japan ( Maekawa et al., 2018).

Figures

Fig. 14 Neogondolellinae, Novispathodinae and uncertain from Shanggang. Magnification is × 80.The scale bar is 400 μm. All elements are considered to be P1 elements if not specifically identified otherwise.A, Eurygnathodus costatus (Staesche); SHA325, PIMUZ 39130. B Eurygnathodus hamadai (Koike); SHA326, PIMUZ 39131. C, D, F, G Novispathodus ex gr. waageni (Sweet); C SHA328,PIMUZ 39238; D SHA328, PIMUZ 39239; F SHA325, PIMUZ 39240;G SHA326, PIMUZ 39241.E Neospathodus ex gr. cristagalli (Huckriede); SHA330, PIMUZ 39182.H Neospathodus dieneri (Sweet); SHA338, PIMUZ 39181

Fig. 11 Faunal turnover rate for all the relying conodont UAZs from South China during the Smithian and Spathian interval. Calculated from the optimal solution given in Fig. 8. Note the early Smithian and early Spathian radiation and the late Smithian and middle/late Spathian extinction