Megacanthopora enodata, Ernst & Wyse Jackson & Aretz, 2015

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 : 180

Megacanthopora enodata n. sp.

( Figs 20 E-I; 21A; Appendix)

ETYMOLOGY. — The species name refers to being it distinct among other Megacanthopora species (from Latin “enodatus”, distinct).

HOLOTYPE. — SMF 21.891 .

PARATYPES. — SMF 21.892- SMF 21.896.

TYPE LOCALITY. — Roque Redonde (Montagne Noire, southern France).

TYPE HORIZON. — Carboniferous, Mississippian (upper Visean).

DIAGNOSIS. — Branched colonies of intermediate diameter; exozones wide; large acanthostyles and abundant aktinotostyles; metazooecia common; rare basal diaphragms; autozooecial walls laminated with numerous mural spines.

DESCRIPTION

Branched colonies, 1.50-1.90 mm in diameter, with 0.66- 0.82 mm wide endozones and 0.42-0.54 mm wide exozones. Autozooecia tubular, growing for short distance parallel to branch axis, abruptly bending in exozones and intersecting colony surface at nearly right angle; having polygonal shape in transverse section of endozone. Autozooecial apertures oval to slightly polygonal, arranged irregularly on branches. Basal diaphragms rare, thin, planar. Aktinotostyles abundant, arranged irregularly between autozooecia. Acanthostyles large, with narrow hyaline cores and wide laminated sheaths, arranged irregularly on the colony surface. Metazooecia small and short, arranged irregularly on the colony surface. Autozooecial walls finely laminated, with dark dividing layer, 0.01-0.02 mm thick in endozone; laminated, without distinct boundaries, protruded by abundant mural spines, 0.18-0.19 mm thick in exozones. Mural spines irregularly arranged in exozonal wall, opening into autozooecial cavities and on colony surface, 0.005 -0.010 mm in diameter.

COMPARISON

Megacanthopora enodata n. sp. differs from M. fallacis Moore, 1929 in thinner branches (branch diameter 1.50-1.90 mm vs 2.0- 3.5 mm in M. fallacis ) and in smaller distances be- tween aperture centres (0.30-0.44 mm vs 0.33-0.60 mm in M. fallacis ). Megacanthopora enodata differs from M. gracilis Dunaeva, 1973 from the Lower Carboniferous (Namurian) of Ukraine in larger apertures (aperture width 0.13-0.19 mm vs 0.10-0.18 mm in M. gracilis ).

Order FENESTRATA Suborder FENESTELLINA Astrova & Morozova, 1956 Family FENESTELLIDAE King, 1849

Figures

FIG. 20. — A-D, Saffordotaxis incrassata (Ulrich, 1888); A, longitudinal section showing aktinotostyles in the autozooecial wall (arrow),SMF 21.889; B, longitudinal section, SMF 21.890; C, tangential section, SMF 21.890; D, branch transverse section, SMF 21.886; E-I, Megacanthopora enodata n. sp.; E, branch transverse section,paratype SMF 21.893; F, branch transverse section,paratype SMF 21.895; G, longitudinal section, paratype SMF 21.894. H, tangential section, holotype SMF 21.891; I, tangential section showing autozooecial apertures, acanthostyles, aktinotostyles and mural styles (arrows), paratype SMF 21.896. Scale bars: A, E, I, 0.2 mm; B-E, H, 1 mm; G, 2 mm.