Lapworthella lucida Meshkova, 1969

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 : 375

Lapworthella lucida Meshkova, 1969

Fig. 23A–F, J, K .

1969 Lapworthella lucida Meshkova sp. nov.; Meshkova 1969: 167, pl. 53: 5.

1974 Lapworthella lucida ; Repina et al. 1974: 81, pl. 18: 7, 8.

Material.—Several tens of calcium phosphate sclerites, including figured SMNH X11018–11025, from samples 19/1.5, 19/3.5, 19/5.5, 20/1B, lower Botoman stage (correlated with the lower part of Cambrian Stage 4), Khorbusuonka River. Several sclerites from sample 21/112, upper Judomia –Uktaspis ( Prouktaspis ) Zone, Atdabanian stage (correlated with the Cambrian Stage 3), lower Lena River. Siberia, Russia.

Description.—Straight or irregularly curved sclerites up to 2 mm long with rounded isometrical aperture, up to 0.5 mm in diameter. Wall with transversal ribs covered with growth lines and tubercles directed towards the apex of sclerite alternating with relatively much broader intervening rings covered with tubercles of two distinctly different sizes. The apical end of sclerite is extended, tapered and tuberculated.

Remarks.—Different from other species in having broader intervening spaces (rings) between ridges and tubercles of two distinctly different sizes scattered on the surface of the rings and apical part.

Stratigraphic and geographic range.—Upper part of Cambrian Stage 3–lower Stage 4, Siberian Platform.

Figures

Fig. 23. Tommotiid Lapworthella Cobbold, 1921 from the Cambrian Erkeket Formation, Khorbusuonka River (A–D, F–L, O–Q) and Tyuser Formation, lower reaches of the Lena River (E, M, N), Siberia, Russia; samples 11/18.7 (G, L), 11/21.6 (H, I), 19/1.5 (D), 19/5.5 (F, J, K), 19/31.75 (Q), 20/1B (A–C), 20/5B (O, P), 21/22.7 (M, N), 21/112 (E). A–F, J, K. Lapworthella lucida Meshkova, 1969 sclerites, SMNH X11018–11025, respectively. G–I, L–N. Lapworthella tortuosa Missarzhevsky in Rozanov and Missarzhevsky, 1966 sclerites, SMNH X11026–11031, respectively. O–Q. Lapworthella dentata Missarzhevsky in Rozanov et al., 1969 sclerites, SMNH X11032–11034, respectively. Scale bar 250 µm.