Discretella aff. discreta ( 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 : 45

Discretella aff. discreta ( Müller, 1956)

Figs. 15B, J ; 16C ?.

1989 Neospathodus bransoni (Müller) ; Tang, p. 417, pl. 29, fig. 10.

2009 Guangxidella ? sp. A; Orchard & Zonneveld, p. 780, fig. 14, parts 33, 34.

2013 Discretella discreta (Müller) ; Yan et al., p. 516, fig. 6W.

Number of specimens:>15

Diagnosis. Segminate P 1 element with rounded, upturned basal cavity at the posteriormost part. Large conspicuous cusp above basal cavity. Discrete, smaller upright denticles in the anterior part.

Description. Tese P 1 elements have markedly discrete denticles and a large cusp. Te lower margin is straight in the anterior and upturned at the posterior part. Te basal cavity is drop-shaped, being rounded at the posterior edge and tapered at the anterior end. Te cusp is relatively large and reclined. A small, accessory, posterior denticle is occasionally present.

Remarks. In comparison to Discretella discreta , this species has a rounded posterior margin of the basal cavity, more discrete denticles and the cusp is relatively larger and often recurved. In lateral view, the lower margin is upturned as in morphotype B of Discretella discreta (Maekawa & Igo, in Shigeta et al., 2014).

Occurrence. Luolou formation, Owenites beds Smithian age, Shanggang road cut, Guangxi, South China.

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 (See legend on previous page.)