Anabarites trisulcatus Missarzhevsky

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 : 499

Anabarites trisulcatus Missarzhevsky in Voronova and Missarzhevsky, 1969

Fig. 69A, E .

Material.—Two calcium phosphatic internal moulds, SMNH X 4818 and 4819, from sample 7/25.6. Emyaksin Formation,

Bol’shaya Kuonamka River; correlated with the Profallotaspis jakutensis Zone , lower Atdabanian Stage.

Description.—Irregularly curved, slowly expanding internal moulds with tri-fold transverse profiles. Three rounded lobes are separated by narrow and shallow but distinct, grooves. The smaller mould (presumably a younger growth stage) carries transverse growth lines ( Fig. 69E ).

Remarks.— Anabarites spp. described herein are the first occurrences of anabaritids from Stage 3 in Siberia. These forms often occur within the Terreneuvian Medvezhya and lower Emyaksin Formations of the Anabar Uplift (see Kouchinsky et al. 2009). Anabarites trisulcatus is indicated from the low- er part of the section by Val’kov (1975: 12; see also Val’kov 1987: fig. 3). Outside the Siberian Platform anabaritids are reported to range into the Cambrian Series 2, Atdabanian– Botoman equivalent strata, in Mongolia ( Esakova and Zhegallo 1996), South and North China ( Feng 2005; Li et al. 2007; Steiner et al. 2007), Australia ( Bengtson et al. 1990), Baltica ( Kouchinsky et al. 2009) , and possibly in the Mediterranean region ( Elicki 1994).

Stratigraphic and geographic range.—Lower Cambrian worldwide (see Kouchinsky et al. 2009).

Figures

Fig. 69. Anabaritids from lower Cambrian Emyaksin Formation, Bol’shaya Kuonamka River and Malaya Kuonamka River, Anabar Uplift, Siberia. A, E. Anabarites trisulcatus Missarzhevsky in Voronova and Missarzhevsky, 1969; sample 7/25.6. A. SMNH X 4818; transversal (A 1) and longitudinal (A 2, A 3) views. E. SMNH X 4819; transversal (E 1) and longitudinal (E 2, E 3) views. B, C. Anabarites cf. A. kelleri Missarzhevsky, 1989. B. SMNH X 4820, sample 3/53.5; longitudinal (B 1, B 2) and oblique transversal (B 3) views. C. SMNH X 4821, sample 6/59.3; transversal (C 1) and longitudinal (C 2) views. D. Anabarites cf. Kotuithes biplicatus Missarzhevsky, 1989; SMNH X 4822, sample 3/59; longitudinal (D 1) and transversal (D ) views. Scale bar 600 μm.