Tianzhushania longa Qian, Chen, and Chen, 1979

Kouchinsky, Artem, Bengtson, Stefan, Landing, Ed, Steiner, Michael, Vendrasco, Michael & Ziegler, Karen, 2017, Terreneuvian stratigraphy and faunas from the Anabar Uplift, Siberia, Acta Palaeontologica Polonica 62 (2), pp. 311-440 : 379-380

Tianzhushania longa Qian, Chen, and Chen, 1979

Fig. 44H–J .

Material.—Eight fragments of internal moulds from sample K1a/47 (section 2, Fig. 1) and a single internal mould from 4/27.5 (section 96-4, Fig. 2 ), including figured SMNH X5798–5800, from the upper Nemakit-Daldyn and basal Emyaksin formations, respectively, Anabar Uplift, Siberian Platform, Russia. Correlated with the upper Fortunian Stage.

Description.—Horn-shaped sclerites, gently curved in one plane, with a broadly oval cross-section. Upper/convex surface of sclerite with two to four distinct longitudinal ridges, tranverse folds trend laterally at an angle to the axis of sclerite ( Fig. 44J ). Lower/concave surface flattened, convex in cross-section with faint longitudinal sculpture (as replicated on internal moulds). Intersection of longitudinal and transverse sculpture produces regularly distributed low bumps ( Fig. 44I ).

Remarks.—The material includes internal moulds similar to sclerites and internal moulds referred to Lomasulcachites macrus by Devaere et al. (2013: fig. 9). The proximal and distal portions of the sclerites are broken off, but cross-section, regular curvature, and sculpture are similar to the latter species’ sclerites. The Siberian material is also similar to phosphatized sclerites of Tianzhushania tetramera Esakova (in Esakova and Zhegallo 1996: pl. 12: 1‒3) from western Mongolia. Because of their morphological similarity, we consider herein Lomasulcachites Qian and Jiang in Luo et al., 1982 to be a junior synonym of Tianzhushania . Tianzhushania has not been previously reported from the Siberian Platform.

Stratigraphic and geographic range.— Upper Fortunian Stage of Siberian Platform, upper Fortunian ( Paragloborilus subglobosus – Purella squamulosa Assemblage Zone ) and Fortunian–Cambrian Stage 2 transitional interval ( Watsonella crosbyi Assemblage Zone ) of South China (Qian and Bengtson 1989; Parkhaev and Demidenko 2010; Devaere et al. 2013; Yang et al. 2014), upper Fortunian of Iran (upper part of Upper Shale Member, Soltanieh Formation, Elborz Mountains; Latouchella – Obtusoconus Assemblage Zone Zone IV ]; Hamdi 1995), upper Fortunian–lower part of

Cambrian Stage 2 of western Mongolia ( Esakova and Zhegallo 1996) and France (Kerber 1988; Devaere et al. 2013).

Figures

Fig. 44. Siphogonuchitid sclerites from early Cambrian Nemakit-Daldyn Formation of western Anabar Uplift, Siberia, Russia; samples K1a/43 (A), 1282 (B), K1a/36A (C), 2/A (D, E, G), and K1a/47 (F, H–J) from section 2. A, D–G. Siphogonuchites subremualis (Bokova, 1985), calcium phosphatic internal moulds, SMNH X5791 (A), SMNH X5794–5797 (D–G, respectively). A1, oblique lateral view of basal part of articulated sclerite group; A2, lateral view of sclerites; D1, view of lower surface of sclerite; D2, lateral view; E1, view of upper surface at distal end; E2, transversal view; G1, G2, views of lower side of basal part of sclerite. B. Dabashanites mirus Chen, 1979, group of articulated phosphatized sclerites, SMNH X5792; B1, B2, oblique lateral views. C. Siphogonuchites triangularis Qian, 1977; pyritised internal mould in lateral view, SMNH X5793. H–J. Tianzhushania longa Qian, Chen, and Chen, 1979; calcium phosphatic internal moulds, SMNH X5798–5800, respectively; H, J, lateral; I, transverse views. Scale bar 250 μm (A), 500 μm (B, D1, E–J), 1 mm (C, D2).

Fig. 2. Composite δ13Ccurve for the Bol’shaya Kuonamka River sections 96-4, 5, and 5a and sampled horizons with fossiliferous samples (arrows with carb numbers). Arrow 4/4 indicates “marker bed with angustiochreids” (Val’kov 1975; Kouchinsky et al. 1999). For section 96-6 see Kouchinsky et al. (2001, 2015a). Shift in stratigraphic column at Manykay–Emyaksin formations contact indicates position of sequence boundary. Stratigraphic ranges and first appearances of fossils (see SOM 1): 1, first appearance of helcionellid molluscs; 2, Oelandiella korobkovi; 3, Securiconus cf. simus; 6, Obtusoconus vostokovae; 7, Obtusoconus cf. mirabilis; 8, Anabarella plana; 13, Aldanella attleborensis; 14, Aldanella cf. sibirica; 22, Purella antiqua; 24, Yunnanopleura accurata; 34, Lopochites sp.; 35, Tianzhushania longa; 37, first appearance of Halkieria sp.; 38, Chancelloria symmetrica; 42, Khetatheca cotuiensis; 44, Conotheca cf. mammilata; 46, Turcutheca sp.; 47, Cupitheca sp.; 50, Orthothecid operculum type C; 51, Protohertzina anabarica; 52, Fomitchella infundibuliformis; 53, Fomitchella aff. infundibuliformis; 54, Fomitchella acinaciformis; 55, Fomitchella aff. acinaciformis; 56, Hyolithellus vladimirovae; 57, Hyolithellus sp.; 60, Selindeochrea cf. tecta; 61, Selindeochrea tripartita; 62, Selindeochrea missarzhevskyi; 63, Selindeochrea ternaria; 64, Anabarites trisulcatus; 65, Anabarites latus; 66, Anabarites natellus; 67, Anabarites kelleri; 68, Anabarites biplicatus; 69, Anabarites tristichus; 70, Anabarites compositus; 71, Anabarites hexasulcatus; 72, Anabarites hariolus; 73, Aculeochrea rugosa; 74, Tiksitheca licis; 75, Cambrotubulus decurvatus; 76, Platysolenites antiquissimus.