Protowenella flemingi Runnegar and Jell, 1976

Kouchinsky, Artem, Alexander, Ruaridh, Bengtson, Stefan, Bowyer, Fred, Clausen, Sébastien, Holmer, Lars E., Kolesnikov, Kirill A., Korovnikov, Igor V., Pavlov, Vladimir, Skovsted, Christian B., Ushatinskaya, Galina, Wood, Rachel & Zhuravlev, Andrey Y., 2022, Early-middle Cambrian stratigraphy and faunas from northern Siberia, Acta Palaeontologica Polonica 67 (2), pp. 341-464 : 403

Protowenella flemingi Runnegar and Jell, 1976

Fig. 24I .

Material.—Several calcium phosphatic and glauconised internal moulds, including figured SMNH Mo194712, from sample 22/50, Sekten Formation, Lena River, Siberia, Russia. Upper Toyonian stage (correlated with the Cambrian Stage 4).

Description.—Planispiral calcium phosphatic internal mould, ca. 0.5 mm in size, coiled through half of a whorl, with rounded cross-section and globose initial part. Subapical side of the mould is delimited by a symmetrically located pair of shallow diverging grooves, termed circumbilical channels.

Remarks.— Peel (2021b) described Protowenella flemingi from the Wuliuan Stage of Greenland with an in-place operculum of a hyolith-type and suggested affinity with orthothecid hyoliths. This is corroborated by presence of planispirally coiled forms among early–middle Cambrian hyoliths (Feng et al. 2001; Kouchinsky et al. 2011; and herein).

Stratigraphic and geographic range.— Cambrian Stage 4– Drumian Stage, Siberian Platform ( Russia), Cambrian

Series 2 of North China and Miaolingian Series of Australia, Laurentia and Bornholm (Baltica) (see Li et al. 2019 for discussion).

Figures

Fig. 24. Molluscs from the lower Cambrian Erkeket Formation, Khorbusuonka River (A–F, J–N) and Sekten Formation, lower reaches of the Lena River (G–I), Siberia, Russia; samples 11/2B (E, F, J), 11/16.1 (K, M, N), 19/12.75 (A), 19/11.75 (B), 20/1B (L, O, P), 20/6B (C, D), and 22/50 (G–I). A, B. Davidonia anabarica (Parkhaev, 2005), internal moulds, SMNH Mo194701 and 194702, respectively. C. Mellopegma sp., internal mould, SMNH Mo194713. D. Stenotheca cf. drepanoida (He and Pei in He et al., 1984), silicified shell, SMNH Mo194714. D1, lateral view; D2, oblique apertural view. →