Hyolithellus sp.

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 : 411-412

Hyolithellus sp.

Fig. 68B, D–F, H, I .

Material.—25 fragmentary phosphatic tubes, including SMNH X5970, 5972, 5973, 5975–5977, from samples K2/6 and K2/60 (section 2, Fig. 1), 1/28.5 (section 1, Fig. 4 ), 5a/6, 5a/34.5, and 5a/34.75 (section 96-5a, Fig. 2 ), Medvezhya and Emyaksin formations, Anabar Uplift, Siberian Platform, Russia. Correlated with the upper Fortunian and lower part of Cambrian Stage 2.

Description.—Slightly irregularly curved tubes with circular cross-section, 150–200 μm in diameter. External surface smooth, with faint transverse folds perpendicular to the longitudinal axis of the tube.

Remarks.—The form is distinguished from Hyolithellus vladimirovae by the smaller size of its tubes and subdued transverse rugae. Deformation of some tubes ( Fig. 68D ) indicates that the original material of the tube was relatively flexible and, thus, phosphatization likely was, in part, secondary. See Kouchinsky et al. (2012: online appendix 1) for the first occurrences of hyolithelminths worldwide.

Figures

Fig. 68. Calcium phosphatic tubes of hyolithelminths Hyolithellus vladimirovae Missarzhevsky in Rozanov and Missarzhevsky, 1966 (A, C, G) and Hyolithellus sp. (B, D, E, F, H, I), from early Cambrian Emyaksin ( A–D, G, I), Medvezhya (E, F), and Kugda-Yuryakh (H) formations, Anabar Uplift, Siberia, Russia; samples 5a/34.5 (A, B), 5a/15.5 (C), 5 a/34.75 (D, I), 5a/10.5 (G), section 96-5a; K2/6 (E, F), K2/60 (H), section 3. A–E. SMNH X5969–5973, respectively. G–I. SMNH X5974–5976, respectively. F. SMNH X5977. Scale bar 500 μm.

Fig. 4. The δ13Ccurve for Kotuj River section 1and sampled horizons with fossiliferous samples (arrows with numbers). Shift in stratigraphic column carb at Nemakit-Daldyn–Medvezhya formations contact indicates position of sequence boundary. Stratigraphic ranges and first appearances of fossils (see SOM 1): 2, Oelandiella korobkovi; 3, Securiconus cf. simus; 4, Bemella jacutica?; 8, Anabarella plana; 9, Watsonella crosbyi; 10, Pseudoyangtzespira selindeica; 11, Aldanella crassa; 13, Aldanella attleborensis; 15, Philoxenella spiralis; 16, Barskovia hemisymmetrica; 18, Khairkhania cf. evoluta; 19, Ceratoconus striatus; 21, Salanyella cf. costulata; 23, Purella cristata; 25, Yunnanopleura sp.; 26, Obscurania auriculata; 29, Protoconus cf. crestatus; 32, Siphogonuchites triangularis; 34, Lopochites sp.; 37, first appearance of Halkieria sp.; 39, first appearance of Chancelloria sp.; 40, Tianzhushanella sp.; 42, Khetatheca cotuiensis; 46, Turcutheca sp.; 48, Orthothecid operculum type A; 52, Fomitchella infundibuliformis; 57, Hyolithellus sp.; 62, Selindeochrea missarzhevskyi; 63, Selindeochrea ternaria; 64, Anabarites trisulcatus; 67, Anabarites kelleri; 68, Anabarites biplicatus; 71, Anabarites hexasulcatus; 74, Tiksitheca licis; 75, Cambrotubulus decurvatus; 76, Platysolenites antiquissimus; 77, Blastulospongia sp.

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.