Dictyocyathidae Taylor, 1910

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 : 452

Family Dictyocyathidae Taylor, 1910 Genus Dictyocyathus Bornemann, 1891

Type species: Dictyocyathus tenerrimus Bornemann, 1891 ; Matoppa Formation , Cambrian Stage 4; Cuccuru Contu, Sardinia, Italy .

Dictyocyathus sp.

Fig. 79C .

Material. —A single phosphatised fragment SMNH Sp11541 from sample 21/21, Tyuser Formation, Lena River, Siberia, Russia. Dokodocyathus regularis Zone, Tommotian stage correlated with the upper part of Cambrian Stage 2).

Remarks. —Phosphatic crust replicating fragment of intervallum built of relatively regular dictyonal network. The latter consists of evenly spaced vertical and radial interpore lintels connected by synapticulae (rod-like horizontal elements of the same size). Such a structure within the entire intervallar space is typical of a number of forms within the Archaeocyathina , but of them, Dictyocyathus is the only one genus known on the Siberian Platform from the Tommotian and Atdabanian strata (Debrenne et al. 2015).

Figures

Fig. 79. Archaeocyatha, phosphatized fragments from the lower Cambrian Erkeket (A, D, H, I) and Chuskuna (E) formations, Khorbusuonka River and Tyuser Formation, lower reaches of the Lena River (B, C, F, G), Siberia, Russia; samples 15/23 (E), 20/1B (A, D, H, I), and 21/21 (B, C, F, G). A, H, I. Ajacicyathina family, gen. and sp. indet., fragments of cups with simple rounded pores, SMNH Sp11535–11537, respectively. A1, H1, lateral view; A2, basal view; H2, oblique lateral view showing inner part of the cup. B, E. Cryptoporocyathus junicanensis Zhuravleva, 1960. B. Wall fragments, SMNH Sp11538–11539, respectively. B1, inner surface of the wall. B2, outer surface of the wall. E. Wall fragment, SMNH Sp11540. C. Dictyocyathus sp., fragment of an intervallar dictyonal network, SMNH Sp11541. D. Carinacyathus sp., fragment of a cup wall with geniculate tubular canals, SMNH Sp11542. F. Cambrocyathellus sp., fragment of a cup, SMNH Sp11543. G. Possible archaeocyath pelta (upper covering structure of the cup), SMNH Sp11544. Scale bar: 1.25 mm (C), 500 µm (B, F–I), and 250 µm (A, D, E).