Tabulipora howsii ( Nicholson, 1881 )

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 : 170

Tabulipora howsii ( Nicholson, 1881)

( Fig. 16 D-H; Appendix)

For synonymy see Wyse Jackson (1996: 151, 152).

MATERIAL. — SMF 21.849- SMF 21.854,TCD.60339, 60340, 60343.

OCCURRENCE. — Carboniferous, Mississippian (Visean); Britain, Ireland, Germany (Velbert Anticline, Rhenish Massif ( Wyse Jackson & Weber, 2005)), Roque Redonde (Montagne Noire, southern France).

DESCRIPTION

Encrusting to submassive colony, 2.7 mm thick. Autozooecia prismatic,having polygonal shape in transverse section,containing rare diaphragms and abundant ring septa. Ring septa concentrated in exozones, occupying about a half of the autozooecial chamber space. Acanthostyles moderately large, concentrated predominantly in maculae, having narrow hyaline cores and wide laminated sheaths. Exilazooecia rare, small, polygonal in transverse section, occurring predominantly in maculae. Endozonal walls granular, 0.015 -0.020 mm thick; exozonal walls monilae-shaped thickened, laminated, serrated, with distinct autozooecial boundaries, 0.05-0.07 mm thick. Maculae consisting of larger autozooecia present, 2.2-2.4 mm in diameter.

COMPARISON

Tabulipora howsii ( Nicholson, 1881) differs from T. urii ( Fleming, 1828) in larger autozooecial apertures (average aperture width 0.28 mm vs 0.19 mm in T. urii ). Tabulipora howsii differs from T. stragula Karklins, 1986 from the Mississippian of Utah, USA in smaller autozooecial apertures (average aperture width 0.28 mm vs 0.39 mm in T. stragula ).

Figures

FIG. 16. — A-C, Ramiporalia robusta Delvolve & McKinney, 1983; A, shallow tangential section showing autozooecial aperture, SMF 21.839; B, C, branch midtangential section, SMF 21.841; D-H, Tabulipora howsii (Nicholson, 1881); D, E, tangential section showing autozooecial apertures and acanthostyles (arrow), SMF 21.852; F, H, longitudinal section showing ring septa, SMF 21.851. Scale bars: A, H, 0.2 mm; B, C, F, G, 1 mm; D, E, 0.5 mm.