Guangxidella bransoni ( Müller, 1956 )

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 : 47-49

Guangxidella bransoni ( Müller, 1956)

Figs. 15E ; 16E .

*1956 Neoprioniodus bransoni n. sp.; Müller, p. 829, pl. 95, figs. 19–21.

1956 Neoprioniodus bicuspidatus n. sp.; Müller, p. 828, pl. 95, figs. 16, 17.

1979 Neospathodus bicuspidatus (Müller) ; Solien, p. 302, pl. 3, figs. 2, 3.

1989 Ozarkodina gigantea n. sp.; Tang, p. 409, pl. 31, figs. 10, 14.

1991 Guangxidella typica n. sp.; Zhang & Yang, p. 33, pl. 1, figs. 1a, b, 2a, b.

2009 Guangxidella bransoni (Müller) ; Orchard & Zonneveld, p. 780, fig. 15, parts 26–28.

2014 Guangxidella bransoni (Müller) ; Maekawa & Igo in Shigeta et al., p. 211, figs. 152.16–152.18, 153–159, 160.1–160.4

2018 Guangxidella bransoni (Müller) ; Maekawa in Maekawa et al., p. 24, figs. 14.7–14.10.

Number of specimens:>30

Description. Te segminate P1 element has variably discrete, laterally compressed denticles whose height decreases to the anterior and a very large, variably reclined, terminal cusp. Te basal margin is up-arched and the basal cavity is flat, cordiform and asymmetrical.

Remarks. Gu. bicuspidatus was differentiated from Gu. bransoni on the basis of its closer spaced denticles, the one in front of the cusp being almost as high as the latter ( Müller, 1956). Yet, given the broad range of intraspecific variation present in large collections such as those illustrated by Shigeta et al. (2014), it is in our opinion no longer tenable to keep both species separated. Although both taxa are defined in the same paper by Müller (1956) and the definition of Gu. bicuspidatus appears before that of Gu. bransoni , we have decided to name them bransoni because the etymology of bicuspidatus refers to a 2-cusp element, which is not typical of the revised species. Furthermore, Müller’s holotype of Gu. bicuspidatus is broken, whereas his holotype of Gu. bransoni is better preserved (not broken), better illustrated (also in aboral view) and corresponds better to the revised type.

(See figure on next page.)

Occurrence. USA: Dinner Springs Canyon, Lower Triassic Meekoceras beds, Crittenden Ranch, Elko County, Nevada ( Müller, 1956); Taynes Formation ( Parachirognathus Zone , Utah, ( Solien 1979). British Columbia, Canada ( Orchard & Zonneveld, 2009). Taho Formation, Novispathodus ex. gr. waageni Zone ) Southwest Japan ( Maekawa et al., 2018). Nanpanjiang basin: Bac Tuy Formation, Owenites beds within the Novispathodus ex. gr. waageni Zone , North-eastern Vietnam ( Shigeta et al., 2014). Luolou Formation, Neospathodus waageni Zone , Guangxi, China ( Zhang & Yang, 1991).

Figures

Fig. 15 Neogondolellinae and Mullerinae from Qiakong, Laren and Shanggang. Magnification is ×80.The scale bar is 400 μm. All elements are considered to be P1 elements if not specifically identified otherwise. A, D Neospathodus bevelledi n. sp.; A SHA333,PIMUZ 39176; D, SHA332, PIMUZ 39177. B, J Discretella aff. discreta (MÜller); B SHA304, PIMUZ 39104; J SHA334,PIMUZ 39105. C, L Discretella discreta (MÜller); C SHA334, PIMUZ 39107; L SHA332, PIMUZ 39108. E Guangxidella bransoni (MÜller); SHA304, PIMUZ 39139.F, H, K, M, P Discretella pseudodieneri n. sp.; F QIA124, PIMUZ 39120; H QIA124,PIMUZ SQL54990; K QIA121, PIMUZ 39121; M QIA120, PIMUZ 39122; P LAR232, PIMUZ 39123. G Discretella cf. discreta (MÜller); QIA120, PIMUZ 39109.I sp. indet.; QIA120, PIMUZ 39294. N Discretella? n. sp. B; LAR232, PIMUZ 39112.O Discretella? n. sp. C; SHA342,PIMUZ 39114

Fig. 16 Neogondolellinae, Novispathodinae and Mullerinae from Shanggang and Youping cascade. Magnification is ×80.The scale bar is 400 μm. All elements are considered to be P1 elements if not specifically identified otherwise. A, F, M Discretella? n. sp. C; A YC16,PIMUZ 39115; F YC16, PIMUZ 39116; M SHA342C, PIMUZ 39117. B Discretella? n. sp. B;YC16, PIMUZ 39113. C Discretella aff.discreta (MÜller);YC22,PIMUZ 39106. D, S Discretella discreta (MÜller); D YC16, PIMUZ 39110; S SHA304C, PIMUZ 39111. E Novispathodus ex gr. abruptus (Orchard);YC41, PIMUZ 39225. G–I, K, L, N, O Discretella pseudodieneri n. sp.; G YC16, PIMUZ 39124; H YC25, PIMUZ 39125; I SHA304C,PIMUZ 39126; K YC22, PIMUZ 39127,L YC25, PIMUZ 39128; N SHA304C,PIMUZ 39129; O SHA343C,PIMUZ SQL54979. J Guangxidella bransoni (MÜller);YC16, PIMUZ 39140. P–R Neospathodus bevelledi n. sp.; P SHA 304C,PIMUZ 39178; Q SHA333C, PIMUZ 39179; R YC12, PIMUZ 39180

Fig. 26 (See legend on previous page.)