Ascopora Trautschold, 1876

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 : 685

Genus Ascopora Trautschold, 1876

Type species: Ceriopora nodosa Fischer von Waldheim, 1837 , Carboniferous, Russia, by subsequent designation ( ICZN 1994, Wyse Jackson 1993).

Remarks.— Kruchinina (1980) erected the genus Ascoporella with Geintzella borealis Stuckenberg, 1895 , from the Sakmarian of Belaya River, Timan, Russia as type species. Ascoporella is incorrectly described as a new genus in Morozova and Kruchinina (1986: 65), and Ascopora grandis Kruchinina, 1973 is erroneously assigned as type species. In the original description of Ascoporella by Kruchinina in 1980, and the repeated description by Morozova and Kruchinina in 1986 Ascoporella is distinguished from Ascopora in having thicker branches, a wider bundle of parallel zooecial in the endozone and often unevenly thickened or beaded exozonal zooecial walls. The number of parallel zooecial in the central bundle ranges from 15 to 30 as observed in longitudinal thin sections. It is difficult to accept these characters as being diagnostic for Ascoporella as the illustrated specimens in Kruchinina (1980) and Morozova and Kruchinina in (1986) deviate strongly from the definitions. In these publications the following can be observed from the illustrations: Ascoporella grandis ( Kruchinina, 1973) has 10–13 parallel zooecial in the central bundle and the walls are not beaded. Ascopora borealis ( Stuckenberg, 1895) has indeed beaded walls, 13–15 parallel zooecial in the central bundle, but a zoarium diameter of 13–18 mm (measured from the original material in Nikiforova 1938: pl. III, VI) instead of 30–40 mm as given by Morozova and Kruchinina (1986). Ascoporella enormis Kruchinina, 1980 is the only species that fulfills the diagnostic characters being 40–45 mm in diameter, having 20–22 parallel zooecial in the central bundle and having thickened or beaded exozonal zooecial walls.

Ascopora magniseptata Shul’ga−Nesterenko, 1955 Fig. 6G.

Material examined.—Measurements based on 5 zoaria in the following samples: Hyrnefjellet, sample ZPAL Br. 12/H10, thin section PMO 170.906; sample and two thin sections ZPAL Br. 12/H30; Gipsvika, thin sections PMO 170.911A, 170.932B, C.

Description.—Cylindrical dichotomically branching colonies averaging 2 mm in diameter. Exozone 0.52 mm wide. Axial bundle of parallel zooecia about 0.52 mm in diameter with 4 to 5 parallel zooecial tubes as observed from longitudinal sections. One distinct proximal hemiseptum is present in zooecial tubes in the transition between the exozone and the endozone. Apertures elongated oval, about 0.28 mm long and 0.12–0.13 mm wide. There are 3.5–4 apertures per 2 mm along colony and 6.3–7.1 diagonally. Distance between apertures longitudinally average 0.53 mm. Large acanthostyles 0.10–0.14 mm in diameter, stylets are present in ridges between apertural rows. Zooecial wall in exozone is about 0.10–0.12 mm in thickness; endozonal wall about 0.006 –0.010 mm.

Measurements.—See Table 3.

Stratigraphic and geographic range.—Occurrence on Svalbard: Asselian, middle part of the Tyrrellfjellet Member, and the Treskelodden Formation. Gzhelian of the Urals, Russia (Shul’ga−Nesterenko 1955).