Discretella, Orchard, 2005

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 : 46

Discretella ? n. sp. B

Figs. 15N ; 16B

Number of specimens:>10

Diagnosis. Segminate P 1 element with subsymmetrical, posteriorly rounded and anteriorly tapered basal cavity. Large terminal, subtriangular, recurved cusp. Anterior process bearing a few denticles only.

Description. Te element shows a large cusp at the posterior end. In lateral view, the large, recurved, subtriangular cusp is about as high as the whole unit is long. An anterior process with two or three small upright to reclined denticles is present. Te lower margin is straight to concave. In aboral view, the subsymmetrical basal cavity is sub-rounded at the posterior margin and tapers towards the anterior end.

Remarks. Tese P 1 elements most closely resemble Discretella aff. discreta , but differ in having a much shorter anterior process and recurved denticles. Tey also bear some superficial resemblance with the P 1 elements of the Spathian–Anisian genus Cornudina , but differ in their conformation of the basal cavity. Urdyella unicorna n. gen. n. sp. usually has a much thinner and larger, sickleshaped cusp and a rounded basal cavity.

Because of the absence of a posterior process, some elements, especially arched ones, resemble homologous elements of Guangxidella and could possibly be assigned to that genus, but their basal cavity do not match those of Guangxidella and resemble instead that of Discretella aff. discreta , hence we tentatively retain them within Discretella .

Occurrence. South China: Luolou, Smithian age, Laren, Guangxi.

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.)