Gladigondolella laii Chen

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 : 19-21

Gladigondolella laii Chen morphotype B

Fig. 13E, F, H, I

2015 Neogondolella ? n. sp. B; Chen et al., figs. 9.9–9.10.

2019 Neogondolella ? n. sp. A Chen; Liu et al., p. 14, pl. 4, fig. 19 (only).

2019 Neogondolella ? n. sp. B Chen; Liu et al., p. 14, pl. 4, fig. 9.

2021 Gladigondolella laii sp. nov.; Chen et al., figs. 4.5, 4.22, 4.25, 4.26 (only).

Material. ca. 20 specimens.

Diagnosis. Segminiplanate P 1 element, narrow platform tapers towards the anterior, denticles moderately discrete. Very large, distinct, terminal, strongly reclined cusp.

Description. Te platform is narrow, subparallel, slightly upturned and tapers towards the anterior end. Te posterior margin is rounded in a narrow platform brim around the large terminal cusp. Te cusp is massive and inclined posteriorly. Te carina is moderately high with pointed denticles which are almost uniform in height.

Remarks. Te large terminal cusp differs from Borinella whose denticles are also higher and more discrete, but resembles that of Scythogondolella . Yet, Gl. laii morphotype B lacks a prominent rounded basal loop surrounding a small pit, a distinctive feature of Scythogondolella . Chen et al. (2015) suggests that their Ng. n. sp. B could be a juvenile stage of Ng. n. sp. A (reassigned here and in Chen et al. (2021) to Gladigondolella laii see above) based on size considerations and the fact that they are both found in the same interval. Yet, they were not found in the same samples and the small forms ( Gl. laii morphotype B) lack a posterior process, although the juvenile forms of ‘true’ gladigondolellids usually bear a posterior process. Hence, we tentatively keep them as separate morphotypes. Nevertheless, in Chen et al. (2021), both forms are found in the same sample (e.g. figs. 4.23 and 4.24) and can therefore be considered as different growth stages.

(See figure on next page.)

Fig. 13 Gladigondolellinae , Neogondolellinae and Cornudininae from Qiakong, Laren, Shanggang and Lilong. Magnification is ×80.The scale bar

is 400 μm. All elements are considered to be P 1 elements if not specifically identified otherwise. A Borinella buurensis (Dagis) , LAR212, PIMUZ 39103.

B, C, G Gladigondolella laii (morphotype A); B LAR231C, PIMUZ 39132; C BAN2, PIMUZ 39133; G LAR227C, PIMUZ 39134. D, sp.indet.(P 2 element?), SHA319, PIMUZ 39293. E, F, H, I Gladigondolella laii (morphotype B); E LIL510,PIMUZ 39135; F LIL512, PIMUZ 39136; H QIA140, PIMUZ 39137; I LIL510,PIMUZ 39138. J–L, O, Spathicuspus spathi (Sweet) ; J QIA141, PIMUZ 39300; K QIA144, PIMUZ 39301; L BAN1, PIMUZ 39302; O SHA322,PIMUZ 39303. M, P Spathicuspus n. sp. A; M QIA144, PIMUZ 39297; P, QIA143, PIMUZ 39298. N, R Spathicuspus spathi (juvenile) (Sweet); N, LIL515D, PIMUZ 39304; R QIA143,PIMUZ 39305. Q Spathicuspus n. sp. B; LAR226C, PIMUZ 39299

Occurrence. Ic. collinsoni and Tr. homeri zone, Luolou formation, Jiarong, Guizhou, South China ( Chen et al., 2015).

Figures

Fig. 13 (See legend on previous page.)