Anabaritidae Missarzhevsky, 1974

Kouchinsky, Artem, Bengtson, Stefan, Landing, Ed, Steiner, Michael, Vendrasco, Michael & Ziegler, Karen, 2017, Terreneuvian stratigraphy and faunas from the Anabar Uplift, Siberia, Acta Palaeontologica Polonica 62 (2), pp. 311-440 : 412

Family Anabaritidae Missarzhevsky, 1974

Remarks.—Anabaritids are attributed, in agreement with most other reports (see Kouchinsky et al. 2009), to diploblastic animals, and are probably cnidarians. Given the uncertainties in assignment of the Cambrian cnidariomorphs and the fact that anabaritid tubes exhibit an unusual type of tri-radial symmetry, they are placed among stem-group cnidarians in which a derived and “modern” type of radial symmetry was not yet established. It is also important to consider that an extant type of tissue differentiation present in crowngroup cnidarians may not have been achieved in lower–middle Cambrian stem-group cnidarians (Park et al. 2011). The affinities, occurrences and systematics of anabaritids are reviewed by Kouchinsky et al. (2009). Kouchinsky et al. (2009: appendix 1 in the supplementary material) list 72 species (including 10 nomina nuda) and 19 genera (including 2 nomina nuda) of anabaritids that have been formally described. In addition, two formally described species can be added to the list. These include Aculeochrea mesezhnikovi Vasil’eva, 1998, and A. trilamellosa Vasil’eva, 1998 (by original designation; see remarks in the description of Anabarites compositus Missarzhevsky in Rozanov et al., 1969, below). The majority of the anabaritid species were originally reported from the Terreneuvian Series of the Siberian Platform, where they are now also known from the younger Atdabanian Stage (lower part of Cambrian Stage 3) of the eastern Anabar Uplift (see Kouchinsky et al. 2015a). Most of the tri-radial symmetrical anabaritid tubes from our collection can be separated into two groups (genera), those with three prominent longitudinal keels and weakly expressed transverse sculpture ( Selindeochrea ) and those with variously expressed, transverse sculptural elements ( Anabarites ).