Polypora marginata M’Coy, 1844

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 : 192

Polypora marginata M’Coy, 1844

( Fig. 26 B-E; Appendix)

Polypora marginata M’Coy, 1844: 206 , pl. 29, fig. 5. — Miller 1963: 168, pl. 24, fig. 3 (non Geinitz, 1866: 69, pl. 5, figs 11a, b, 12a, b).

Polypora marginata M’Coy in Griffith, 1842: 10 (nomen nudem).

MATERIAL. — SMF 21.921- SMF 21.922.

OCCURRENCE. — Carboniferous, Mississippian (Visean); Roque Redonde (Montagne Noire, southern France); Co. Tyrone, Ireland.

EXTERIOR DESCRIPTION

Reticulate colonies composed of moderately wide branches jointed by wide dissepiments. Autozooecia arranged in 3-4 alternating rows on branches. Autozooecial apertures rounded to oval.Low undulating longitudinal ridges/striations between autozooecia developed. Fenestrules subrectangular, long and narrow.

INTERIOR DESCRIPTION

Autozooecial chambers moderately long, generally rhombic to roughly hexagonal in the mid tangential section. Hemisepta absent.External laminated skeleton well-developed,traversed by abundant small microacanthostyles.Heterozooecia not observed.

COMPARISON

Polypora marginata M’Coy, 1844 is easily distinguished from other Polypora species of the same age on the basis of possessing elongate rounded fenestrules with short dissepiments, and wavy longitudinal striations on the obverse surface.

Figures

FIG. 26. — A, Polypora dendroides M’Coy, 1844, longitudinal section, SMF 21.919. B-E, Polypora marginata M’Coy, 1844, SMF 21.921; B-D, mid-tangential section showing autozooecial chambers and apertures; E, tangential section showing autozooecial apertures, undulatory striations and branch surface; F-H, Diploporaria tenella Wyse Jackson, 1988, mid-tangential section showing autozooecial chambers with hemisepta (arrow) and apertures, SMF 21.923. Scale bars: A, G, 0.5 mm; B, C, F, 2 mm; D, E, 1 mm; H, 0.2 mm.