Ascopora cf. sterlitamakensis Nikiforova, 1939

Nakrem, Hans Arne, Błażejowski, Błażej & Gaździcki, Andrzej, 2009, Lower Permian bryozoans from southern and central Spitsbergen, Svalbard, Acta Palaeontologica Polonica 54 (4), pp. 677-698 : 686

Ascopora cf. sterlitamakensis Nikiforova, 1939

Fig. 6L–N.

Material examined.—Five partial zoaria in the following samples: Hyrnefjellet, samples ZPAL Br. 12/G14 (thin sections PMO 170.895A−C), ZPAL Br. 12/G15 (thin section PMO 170.891), and sample and one thin section ZPAL Br. 12/G14. For measurements, see Table 5.

Ascopora cf. sterlitamakensis is distinguished in displaying multiple regenerated growth layers, with an exozone up to 3.3 mm wide, but in many other charcters similar to A. sterlitamakensis . This growth pattern is very much like the description of Tabulipora borealis ( Stuckenberg, 1895) by Nikiforova (1938: 221–222, pl. 4: 1, 2), subsequently re−assigned as Ascoporella borealis by Morozova and Kruchinina (1986). Some specimens have an unusually widened exozone, up to 5.25 mm wide with no signs of overgrowth. Circular cavities/openings, up 0.17–0.20 mm in diameter, are observed in the exozone of these colonies with extraordinary exozone. These holes are herein interpreted as being the results of bioerosion by unknown parasites drilling into the calcitic exozone of the bryozoan zoaria ( Fig. 6L). Some cavities are later filled in with sediments and skeletal debris, e.g., coral and echinoderm fragments ( Fig. 6N).