Angochitina sp. 3

Li, Yangui, Yan, Chunbo, Wang, Chuanshang, Maletz, Jörg, Liang, Yan, Yao, Huazhou, Wu, Haizhi, Chen, Weixiong, Cheng, Jingqing, Fang, Zichen & Wang, Xiaofeng, 2025, Chitinozoans from the Telychian (Llandovery, Silurian) Shenxuanyi Member, upper Ningqiang Formation of the northwestern Yangtze Platform, China, Swiss Journal of Palaeontology (20) 144 (1), pp. 1-33 : 24-25

Angochitina sp. 3 ( Figs. 7N–S and 8A, B )

Material: Systematic study was performed based on 64 flattened specimens.

Description: It is a kind of slender chitinozoan with a total length of 128–178 μm, and a L/Dp ratio of 2.24–3.24. Te well-preserved specimens show that its chamber is ovoid, with convex flanks and rounded margin and base. Te flexure is marked. Te neck is columnar (up to 1/2 of the total length), transitions into a short membranous collar at the aperture, and some specimens with intraspecific variation show that its neck slightly expanded toward the oral pole. Te vesicle surface is covered with small, irregular, and very sparse verrucate ornaments. Te ornaments on the neck surface are significantly less than those on the chamber surface.

Measurements: Measured data based on 16 specimens.

Comparison and remarks: Tis taxon is distinguished from A. longicollis and Angochitina cf. paucispinosa Miller et al., 1997 by its small, sparse, and verrucate ornaments rather than spinous ornaments. Te morphology of its neck and chamber is consistent with that of Angochitina sp. 1 in this paper, but the membranous ornaments of Angochitina sp. 1 is inconsistent with its verrucate ornaments. Terefore, this study assigns it tentatively to Angochitina sp. 3 .

Locality and stratigraphic horizon: Herein, specimens were found from the Shenxuanyi Member.

Figures

Fig. 7 Llandovery chitinozoans from the Shenxuanyi Member.Scale bars represent 50 μm (except the scale bar of specimens D, E, G, K and M represent 10 μm). A–E Angochitina synaphacantha (Geng et al., 1997) (A N39-27. B N42-8. C N23-7. D, E close-up of N39-27 showing the ornaments). F-G Angochitina sp. 1 (F N4-21. G close-up of N4-21 showing the ornaments). H–M Angochitina sp. 2 (H N5-7. I N2-12. J N7-11. K close-up of N5-7 showing the ornaments. L N3-19. M close-up of N3-19 showing the ornaments). N–S Angochitina sp. 3 (N N3-14. O N10-3. P N8-14. Q N64-7. R N58-67. S N11-1)

Fig. 8 Llandovery chitinozoans from the Shenxuanyi Member. Scale bars represent 50 μm (except the scale bar of specimens A, B, I and M represent 10 μm). A, B Angochitina sp. 3 (A close-up of N8-14 showing the ornaments. B close-up of N11-1 showing the ornaments). C–E Angochitina sp. 4 (C N21-9. D N21-10. E N37-3). F–M Angochitina sp. 5 (F N19-3. G N31-2. H N19-13. I close-up of N19-13 showing the ornaments. J N7-19. K N4-17. L N4-6. M close-up of N7-19 showing the ornaments)