Borinella buurensis ( Dagis, 1984 )

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

Borinella buurensis ( Dagis, 1984)

Fig. 13A

1978 Neogondolella jubata Sweet ; Weitschat & Lehmann, p. 98, pl. 13, figs. 1–6.

*1984 Neogondolella buurensis n. sp.; Dagis, p. 12, pl. 2, figs. 6–15, pl. 3, fig. 1–2, pl. 11, figs. 1–4, pl. 12, figs. 1, 2, pl. 16, figs. 1–4.

1984 Neogondolella elongata Sweet ; Hatleberg & Clark, Pl. 1, fig. 14 (only).

2005 Neogondolella aff. sweeti Kozur & Mostler ; Zhao, p. 131, pl. 13, fig. 1.

2007 Borinella buurensis (Dagis) ; Orchard, p. 113, pl. 1, nr. 7, 15, 27.

2008 Borinella buurensis (Dagis) ; Nakrem et al., p. 528, fig. 4.19.

2008 Borinella aff. buurensis (Dagis) ; Nakrem et al., p. 528, fig. 4.17–4.18.

2008 Borinella buurensis (Dagis) ; Orchard, p. 400, figs. 5.9–5.13.

2012a Borinella aff. buurensis (Dagis) ; Goudemand & Orchard in Goudemand et al., p. 1032, figs. 2AA.

2015 Borinella aff. buurensis (Dagis) ; Chen et al., fig. 9.11. 2018 Borinella aff. buurensis (Dagis) ; Maekawa in Maekawa et al., p. 45, fig. 29.27.

2019 Neogondolella ex. gr. jakutensis Dagis; Chen et al., figs. 4.3, 4.5 (only).

2019 Borinella aff. buurensis (Dagis) ; Liu et al., p. 13, pl. 3, fig. 10 (only).

2021 Borinella aff. buurensis (Dagys) ; Chen et al., fig. 5.9 (only).

Number of specimens. 5

Description. Subsymmetrical segminiplanate P 1 element whose platform extends as a brim around the posterior edge, but not to the anteriormost quarter of the unit. In the posterior half, the platform margins are subparallel in oral view. Te cusp varies in height and may be conspicuous. A smaller posterior denticle may be present in some specimens, in which case, it tends to be offset from the main axis. As in any Borinella species, the denticles become gradually more discrete and taller towards the anterior end. As illustrated by the figured specimen, whose denticles at mid-length are almost as high as the anteriormost ones, this denticulation gradient may be variable.

Remarks. Orchard (2007) suggested that the cusp of theP 1 of B. buurensis is typically weak, contrary to that of B. sweeti . Our collections suggest instead it is variable, as illustrated here. In our view it is difficult to differentiate B. sweeti and B. buurensis .

Occurrence. South China; Nv. pingdingshanensis Zone, Tsoteng section ( Goudemand et al., 2012b), Jiarong section, Guizhou ( Chen et al., 2015): Southwest Japan ( Maekawa et al., 2018): Boreal region; Hedenstroemia zone , Siberia ( Dagis, 1984), Tardus zone, Canadian Arctic ( Orchard, 2008), Spitsbergen ( Nakrem et al., 2008; Weitschat & Lehmann, 1978).

Figures

Fig. 13 (See legend on previous page.)