Primorella zhankurganica, Tolokonnikova & Fedorov, 2022

Tolokonnikova, Zoya A. & Fedorov, Petr V., 2022, Late Devonian-early Carboniferous bryozoans from Zhankurgan (Greater Karatau, Kazakhstan) - taxonomy and palaeobiogeographical implications, Zootaxa 5196 (2), pp. 252-264 : 259

Primorella zhankurganica sp. nov.

Figs 4A–F , Table 5

Holotype. SibGIU 12/28 (section with five colony fragments ).

Material. SibGIU 12/23.1 (micro-CT).

Description. Thin branched colonies. Autozooecial wall 0.02 mm thick in endozone. Diaphragms in the autozooecia absent. Oval autozooecial apertures arranged in diagonal rows; 2 apertures per 1 mm along colony length, 3 diagonally. Autozooecia budding from the central axis at low angles, sharply bending in the exozone and intersecting the colony surface at angles of 80–90°. Abundant aktinotostyles in the walls of the exozone, arranged in regular rows between apertures on the colony surface, displaying distinct core with radially arranged small spines, stellate in cross section.

Comparison. Primorella zhankurganica sp. nov. differs from P. variata Tolokonnikova, 2015 from the upper Tournaisian of Kurgan region of Russia (Tolokonnikova 2015) in narrower colonies (0.70–0.80 mm vs. 0.67–1.05 mm in P. variata ), abundant aktinotostyles (22–24 around each aperture vs 10–16 in P. variata ) and smaller apertures (0.07–0.08x 0.16–0.20 mm vs. 0.01–0.12x 0.17–0.22 mm in P. variata ).

Stratigraphical and geographical ranges. Orgalysay Formation, Mississippian (upper Tournaisian); Karatau, Zhankurgan outcrop, Kazakhstan.

Figures

FIGURE 4. Primorella zhankurganica sp. nov. SibGIU 12/28: A. Fragments of bryozoan colonies in the rock; B. tangential section showingabundant aktinotostyles between apertures (arrow); C,D. longitudinal sectionshowing structure ofaktinotostyles (arrow); SibGIU 12/23.1: E. Micro-CT reconstruction through zoaria; F. Micro-CT reconstruction of colony surface.