Spinofenestella, Termier & Termier, 1971

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 : 186

Spinofenestella sp. 2

( Fig. 23 D-I; Appendix)

MATERIAL. — SMF 21.911.

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

EXTERIOR DESCRIPTION

Reticulate colony formed by straight branches joined by relatively wide dissepiments. Fenestrules rectangular, elongated. Autozooecia arranged in two rows on branches. Autozooecial apertures circular, with low smooth peristome; 3 to 4 apertures spaced per fenestrule length. Keel wide, low, containing small widely spaced elliptical nodes.

INTERIOR DESCRIPTION

Autozooecia relatively long, triangular in mid tangential section; with short to moderately long vestibule in longitudinal section. Axial wall between autozooecial rows strongly undulating; aperture positioned at distal end of chamber. Superior hemisepta long, proximally curved; inferior hemisepta absent. External laminated skeleton well-developed on both obverse and reverse sides. Heterozooecia not observed.

COMPARISON

Spinofenestella sp. 2 is similar to S. tenuiseptata (Schulga- Nesterenko, 1941) from the Carboniferous of northeast Russia (as described by Morozova, 1981, p. 70) in branch width (0.26-0.30 mm vs 0.26-0.28 mm) and fenestrule dimensions (length 0.72-0.75 mm vs 0.55-0.80 mm; width 0.19-0.28 mm vs 0.27-0.45 mm). However, S. tenuiseptata lacks the distinctive superior proximally curved hemisepta developed in the French specimen.

Figures

FIG. 23. — A-C, Spinofenestella cf. simplaris (Trizna, 1961); A-B, mid-tangential section, SMF 21.908; C, tangential section showing nodes on keel (arrow), SMF 21.906; D-I, Spinofenestella sp. 2, SMF 21.911; D-G, tangential section; H, mid-tangential section showing autozooecial chambers; I, autozooecial aperture. Scalr bars: A, E-G,, 1 mm; B, H, 0.2 mm; C, 0.5 mm; D, 2 mm; I, 0.1 mm.