Angochitina sp. 4

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 : 25

Angochitina sp. 4 ( Fig. 8C, D, E )

Material: Systematic study was performed based on four photomicrographs.

Description: Tis chitinozoan has a total length of 151– 161 μm and a chamber diameter of 64–81 μm. Te chamber (with inconspicuous shoulders) is cone-spheroidal, with a broad rounded flexure, flanks, margin, and base. Te long columnar neck usually transitions into a short membranous collar that expands at the aperture. Te vesicle surface (except at the collar) is sparsely covered with thick (width up to 1 μm), long (length up to 10 μm), and simple spinous ornaments (solid spines).

Measurements: Measured data based on three specimens.

Comparison and remarks: Its morphological features are consistent with Angochitina ( Eisenack, 1931) . A. longicollis , Angochitina caspiensis Ghavidel-syooki, 2006, Angochitina cf. echinata Eisenack, 1931 , Angochitina elongate Eisenack, 1931 , Angochitina fentouensis Li & Geng, 1985 , Angochitina rarispinosa Geng , et al., 1997, and Angochitina sinica Cramer, 1970 have smaller spines than this taxon. Furthermore, although this taxon has similar spines to Angochitina heterotricha Geng et al., 1997 , Angochitina cf. paucispinosa Miller et al., 1997 , and Angochitina cf. lebaica Eisenack, 1972b , the vesicle morphology of this taxon is significantly different from theirs. At present, no similar specimens have been reported. Terefore, in this study, it is assigned to Angochitina sp. 4 tentatively.

Locality and stratigraphic horizon: Specimens assigned to this species were recognised in the lower Shenxuanyi Member.

Figures

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)