Pseudonematopora Balakin, 1974

Ernst, Andrej, Wyse Jackson, Patrick N. & Aretz, Markus, 2015, Bryozoan fauna from the Mississippian (Visean) of Roque Redonde (Montagne Noire, southern France), Geodiversitas 37 (2), pp. 151-213 : 174-176

Genus Pseudonematopora Balakin, 1974

TYPE SPECIES. — Nematopora ? turkestanica Nikiforova, 1948 by original designation. Lower Carboniferous of the Middle Asia.

OCCURRENCE. — Upper Devonian (Famennian) to Pennsylvanian (Bashkirian); Europe, Russia, Kazakhstan, China, Mongolia.

DIAGNOSIS. — Ramose colonies with occasional dichotomising branches. Branches of constant width, circular to semicircular in transverse section. Autozooecia occurring in 6 to 16 longitudinal rows, budding in an annular manner, originating from a central axis or median wall. Autozooecial apertures circular to oval in shape, with proximal peristomes. Vesicular skeleton may be present in the exozone. Diaphragms and acanthostyles absent, terminal diaphragms common.

COMPARISON

Pseudonematopora Balakin, 1974 differs from Nematotrypa Bassler, 1911 by absence of hemidiaphragms in autozooecia and nodes on the colony surface.

Pseudonematopora planatus Wyse Jackson, 1996 ( Fig. 18 A-C)

Pseudonematopora planatus Wyse Jackson, 1996: 126-127 , fig. 3c, 10-15. — Ernst 2005: 59, fig. 4c-g. — Ernst & Rodríguez 2013: 187, 8d- 8f.

MATERIAL. — SMF 21.855- SMF 21.859, TCD.60332, 60333, 60339, 60340, 60342, 60344, 60345.

OCCURRENCE. — Mississippian, Visean; Ireland ( Wyse Jackson, 1996), Germany ( Ernst 2005), Carboniferous, Mississippian (upper Visean); Roque Redonde (Montagne Noire, southern France), Spain ( Ernst & Rodríguez 2013).

DESCRIPTION

Ramose colony, circular or slightly angular in cross-section, 0.54-0.75 mm in diameter. Short autozooecia budding in spiral order from the central axis. Hemisepta absent; terminal diaphragms common. Autozooecial apertures oval to teardropshaped, 0.10-0.14 mm wide, arranged in regular diagonal rows. Autozooecia displaying two types of walls – the inner bright granular-prismatic and the outer dark laminated. The inner granular-prismatic walls building three-layered endozone walls consisting of two bright outer layers and the dark inner one. Neither heterozooecia nor styles present.

COMPARISON

Pseudonematopora planatus Wyse Jackson, 1996 differs from P. turkestanica ( Nikiforova, 1948) from the Mississippian (Visean) of Kazakhstan in having thinner branches and smaller apertures (branch width 0.54-0.75 mm vs 0.80-2.80 mm in P. turkestanica ; aperture width 0.10-0.14 mm vs 0.17- 0.22 mm in P. turkestanica ) ( Wyse Jackson 1996, appendix 6), as well as in absence of heterozooecia. Pseudonematopora planatus differs also from P. balakini Gorjunova, 1988 from the Pennsylvanian (Bashkirian) of Mongolia in having thinner branches and smaller apertures (branch width 0.54- 0.75 mm vs 0.88-1.10 mm in P. balakini ; aperture width 0.10-0.14 mm vs 0.18-0.22 mm in P. balakini ), as well as in absence of heterozooecia.

Figures

FIG. 18. — A-C, Pseudonematopora planatus Wyse Jackson, 1996; A, tangential section, SMF 21.857; B, longitudinal section, SMF 21.857; C, Transverse section, SMF 21.856; D-I, Clausotrypa ramosa (Owen, 1973); D, E, branch surface, SMF 21.871; F, tangential section, SMF 21.869; G-H, longitudinal section, SMF 21.869; I, transverse section, SMF 21.862. Scale bars: A-C, E, F, 0.5 mm; D, H, I, 1 mm; G, 2 mm.