Triplicatella sinuosa Skovsted, Peel, and Atkins, 2004

Kouchinsky, Artem, Bengtson, Stefan, Clausen, Sébastien & Vendrasco, Michael J., 2015, An early Cambrian fauna of skeletal fossils from the Emyaksin Formation, northern Siberia, Acta Palaeontologica Polonica 60 (2), pp. 421-512 : 453

Triplicatella sinuosa Skovsted, Peel, and Atkins, 2004

Fig. 29C .

Material.—Single phosphatised operculum, SMNH X 4648, from sample B-247 and a single fragment from sample 7/70; uppermost Emyaksin Formation, Bol’shaya Kuonamka Riv- er; Calodiscus -Erbiella Zone, lower Botoman Stage.

Remarks.—The fossil is very similar to Triplicatella sinuosa from Cambrian Stage 4 of Laurentia ( Skovsted et al. 2004) in having three strongly developed inner folds of the dorsal margin. Two weak ventral folds are recognizable. The lateral margins of the operculum are not completely preserved, but the operculum was presumably elliptical in outline.

Stratigraphic and geographic range.— Bonnia -Olenellus Zone, Dyeran Stage of Greenland and lower Botoman Stage of the Siberian Platform.

Figures

Fig. 29. Hyolith opercula Triplicatella spp. from lower Cambrian Emyaksin Formation, Malaya Kuonamka River and Bol’shaya Kuonamka River, Anabar Uplift, Siberia. A, B. Triplicatella papilio sp. nov. A. SMNH X 4646, holotype, sample K1-3B; dorsal (A1), lateral (A2, A4), inner (A3), and ventral A5, note flattened rounded polygons at the base of the dorsal folds) views. B. SMNH X 4647, paratype, sample 7/70; dorsal (B1) and inner (B2) views. C. Triplicatella sinuosa Skovsted, Peel, and Atkins, 2004; SMNH X 4648, sample B-247; outer (C1), oblique ventral (C2), lateral (C3), and dorsal (C4) views. D. Triplicatella cf. T. peltata Skovsted, Peel, and Atkins, 2004; SMNH X 4649, sample 7/70; dorsal (D1), inner (D2), oblique inner (D3), and lateral D4) views. Scale bar 600 μm, except A1, A5, 300 μm.