Cystodictya Ulrich, 1882

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 : 166

Genus Cystodictya Ulrich, 1882

TYPE SPECIES. — Cystodictya ocellata Ulrich, 1882 by original designation. Lower Mississippian ; Kentucky, USA .

DIAGNOSIS. — Bifoliate colony, strap-like, branching in plane of mesotheca. Autozooecia with peristomes and lunaria. Ridges between autozooecial rows lacking. Mesotheca thin to moderately thick, indistinctly laminated to granular-prismatic, with low ridges, running parallel to ranges of autozooecia. Autozooecia teardrop-shaped at their basis, quadrate in cross-section; partly isolated by boxlike vesicles; recumbent portion short; blunt proximolateral hemisepta at zooecial bend, indenting zooecial cavity and producing slight hook-shaped appearance of autozooecia in deep tangential section. Diaphragms lacking. Walls laminated; boundary serrated, tubules in cortex. Lunarium in exozone, light colored, laminated, some with core and proximal rib. Compound range walls thin in endozone with dark boundary continuous into dark central layer of mesotheca; thick in exozone with many flexures and irregular tubuli. Vesicles small, boxlike, in endozone; low blisters in inner exozone; stereom in exozone; laminated with tubuli and flexures.

OCCURRENCE. —Middle Devonian – Upper Carboniferous;worldwide.

C OMPARISON

Cystodictya Ulrich, 1882 differs from Sulcoretepora d’Orbigny, 1849 by teardrop-shaped apertures, straight mesotheca and autozooecial walls, which are distinctly tripartite in Sulcoretepora and more homogenous in Cystodictya . Furthermore, Cystodictya possesses hemisepta which is absent in Sulcoretepora . Cystodictya differs from Dichotrypa Ulrich in Miller, 1889 by absence of acanthostyles in exterior stereom.