Selindeochrea ternaria

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 : 417

Selindeochrea ternaria (Missarzhevsky in Rozanov et al., 1969)

Fig. 73 .

Material.—Over ten internal moulds, including figured SMNH X5998–6001, from samples 1/29.2 (section 1, Fig. 4 ), 3/12.2, K2/25, K2/26 (section 3, Fig. 3), and 5a/18.5 (section 96-5a, Fig. 2 ), from the lower Emyaksin and Medvezhya formations, Anabar Uplift, Siberian Platform, Russia. Correlated with the upper Fortunian Stage and lower part of Cambrian Stage 2.

Description.—Tubes almost straight or somewhat curved, torted clockwise or counterclockwise, narrow, longitudinally folded in laterally elongate lobes separated by wide V-shaped grooves. Inner surface of the tubes (as replicated by internal moulds) with growth lines.

Remarks.—The narrow blade-like lobes are somewhat similar to the longitudinal keels described above in other species of Selindeochrea . Given that proposed similarity and lack of any prominent transverse sculptural elements, the fossil is tentatively attributed to Selindeochrea .

Stratigraphic and geographic range.— Upper Fortunian Stage and lower part of Cambrian Stage 2 of the Siberian Platform and South China.

Genus Anabarites Missarzhevsky in Voronova and Missarzhevsky, 1969

Type species: Anabarites trisulcatus Missarzhevsky in Voronova and Missarzhevsky, 1969; Anabarites trisulcatus Zone , lower Cambrian (lower Fortunian Stage); mouth of the Kotujkan River, Siberia, Russia.

Figures

Fig. 73.Anabaritid Selindeochrea ternaria (Missarzhevsky in Rozanov et al., 1969), calcium phosphatic internal moulds, from early Cambrian Medvezhya (A, C, D) and Emyaksin (B) formations,Anabar Uplift, Siberia, Russia; samples K2/25 (A), K2/26 (D), 3/12.2 (C), section 3; 5a/18.5 (B), section 96-5a. A. SMNH X5998. B. SMNH X6000. C. SMNH X5999. D. SMNH X6001. A1, C, D, lateral; A2, B, transverse views. 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.