Mackinneyella, MOROZOVA & LISITSYN, 1996

Ernst, Andrej, Tolokonnikova, Zoya & Yarahmadzahi, Hamed, 2012, Upper Devonian (Frasnian) Bryozoa from the Shishtu 1 Formation of Niaz area (eastern Tabas, central Iran), Revue de Paléobiologie 31 (1), pp. 1-14 : 5-6

Mackinneyella sibirica (YANISHEVSKY, 1915)

Pl. III, figs 1-5; Table 4

1915. Polypora sibirica YANISHEVSKY, p. 37, fig. 3.

1933. Polypora sibirica YANISHEVSKY. – NIKIFOROVA, p. 28, pl. 10. figs 1-3.

1948b. Polypora sibirica YANISHEVSKY. – NEKHOROSHEV, p. 38, pl. 10, fig. 8.

1956. Polypora sibirica YANISHEVSKY. – NEKHOROSHEV, p. 215-218, pl. 33, figs 1-2, text-fig. 57.

Table 3: Table 4: Material: Single colony SMF 21.106.

Exterior Description: Reticulate colony with straight branches joined by dissepiments. Bifurcation common. Autozooecia arranged in 4-6 alternating rows on branches, becoming 6-8 in the place of bifurcation and 3 after the bifurcation. Apertures circular, arranged in regular alternating rows, 10-11 spaced per fenestrule length. Fenestrules large, elongate, sub-rectangular. Dissepiments long and narrow. Keels and nodes absent. Internal granular skeleton thick, well developed, continuous in microstyles. Outer lamellar skeleton moderately thick, containing abundant microstyles 0.02- 0.03 mm in diameter.

Interior Description: Autozooecia rhombic in mid tangential section, irregularly shaped at branch bifurcations; with well developed vestibule protruding highly above the colony surface; elongate to branch length; aperture positioned at distal end of chamber. Hemisepta absent. Heterozooecia are secondary nanozooecia, represented by zooecia, sealed by centrally perforated operculum; central opening 0.03-0.05 mm in diameter.

Remarks: Mackinneyella sibirica (YANISHEVSKY, 1915) differs from M. maccoyna (ULRICH, 1890) in absence of massive nodes on the obverse colony surface as well as more autozooecial apertures per fenestrule length: 10-11 vs. 7-9 in M. maccoyna.

Occurrence: Lower Carboniferous (Lower Viséan); River Tom near Tomsk, Siberia, Russia. Ulbin Suit, Lower Carboniferous (Viséan); Altai, Russia. Shishtu 1 Formation, Upper Devonian (Frasnian); Niaz section, eastern Tabas, central Iran.