Bryozoan fauna from the Mississippian (Visean) of Roque Redonde (Montagne Noire, southern France) Author Ernst, Andrej Author Wyse Jackson, Patrick N. Author Aretz, Markus text Geodiversitas 2015 2015-06-30 37 2 151 213 http://dx.doi.org/10.5252/g2015n2a2 journal article 10.5252/g2015n2a2 1638-9395 4534998 urn:lsid:zoobank.org:pub:BA9B2FF0-9D3B-44AF-894F-419DE5AE4C13 Dybowskiella rotunda n. sp. ( Figs 8G , 9 A-C; Appendix) ETYMOLOGY. — The species name refers to the rounded shape of apertures and lunaria (from Latin “ rotundus ” – rounded). HOLOTYPE . — SMF 21.777 . PARATYPE . — SMF 21.778- SMF 21.780. TYPE LOCALITY . — Roque Redonde (Montagne Noire, southern France ). TYPE HORIZON . — Carboniferous, Mississippian (upper Visean). DIAGNOSIS. — Moderately thick encrusting colonies; apertures large, with well developed rounded lunaria; autozooecial diaphragms common to abundant; vesicles large, separating autozooecia in 1-2 rows, 6-10 surrounding each autozooecial aperture. DESCRIPTION Encrusting colony, 0.9-2.9 mm thick. Autozooecia growing from thin epitheca, bending in the early exozone to the colony surface. Basal diaphragms straight or slightly inclined, common to abundant, 2-7 in each autozooecium. Autozooecial apertures circular to oval. Lunaria well-developed, rounded, rounded; ends of lunaria indenting deeply autozooecia. Vesicles large, irregular, separating autozooecia in 1-2 rows, 6-10 surrounding each autozooecia aperture, with rounded roofs, polygonal in tangential section. Autozooecial walls granular prismatic, 0.010 -0.015 mm thick. COMPARISON Dybowskiella rotunda n. sp. differs from Dybowskiella piriforme n. sp. in larger autozooecial apertures (average aperture width 0.34 mm vs 0.21 mm in D. piriforme ) and in presence of diaphragms. Dybowskiella rotunda n. sp. differs from D. regularis Perry & Gutschick, 1959 from the Amsden Formation (Late Mississippian) of Montana , USA , in larger apertures, larger vesicles and smaller number of vesicles around autozooecial apertures (6-10 vs 11-13 in D. regularis ).