Ceriocava sp.

Zatoń, Michał & Taylor, Paul D., 2009, Middle Jurassic cyclostome bryozoans from the Polish Jura, Acta Palaeontologica Polonica 54 (2), pp. 267-288 : 286

Ceriocava sp.

Fig.15 .

Measurements.—AD, 133–200 µm; IWT, 50–133 µm; GTL, 3500 µm; GW, 333 µm; PL, 15–20 µm; PW, 20–28 µm.

Material.—31 colonies: GIUS 8−3509−2, GIUS 8−3509−74– 77, NHM BZ 5612–34.

Description.—Colonies varying from dome− and cone−like with autozooids opening over entire upper surface ( Fig. 15A, B ), or flabellate (flabellotrypiform) with autozooids opening only at subvertical growing edge and frontal surface of colony comprising exterior wall, depressed centrally ( Fig. 15C 1 ).

Autozooidal apertures rounded polygonal, surrounded by thick interzooidal walls (mean thickness 64–81 µm) with ridges at zooidal boundaries giving a honeycomb−like pattern ( Fig. 15A 2 ); terminal or subterminal diaphragms visible in thin−sections. Pseudopores, best visible on frontal surfaces of flabellitrypiform colonies, densely spaced, teardrop−shaped with broad base (mean width 22 µm), pointed distally ( Fig. 15C 2 ).

Gonozooids narrow and elongate, often curved; roof pseudoporous; ooeciopore not identified ( Fig. 15A 3 ).

Remarks.—As interpreted by Walter (1970), Ceriocava corymbosa ( Lamouroux, 1821) encompasses a wide range of colony morphotypes, including the ramose erect forms normally associated with the genus as well as flabellotrypiform and dome−shaped encrusters. Material of this “species” from the Upper Bathonian–Lower Callovian of Balin exhibits a further morphotype: dendroid colonies composed of stacks of cap−like overgrowths ( Taylor 2009). It is beyond the scope of the current paper to resolve the difficult taxonomy of Jurassic Ceriocava which would demand both thin section and SEM study of a large amount of comparative material. However, topotypical Ceriocava corymbosa ( Lamouroux, 1821) from Normandy differs from the Polish material described here by its larger autozooidal apertures (mean diameter 268 µm), much smaller (mean width 10 µm) and denser pseudopores, and shorter but much wider gonozooids.

Stratigraphic and geographic range.—Upper Bajocian to Upper Bathonian of Mokrsko, Bugaj, Ogrodzieniec, and Krzyworzeka, Polish Jura.

Figures

Fig. 15. Cerioporine cyclostome bryozoan Ceriocava sp. from the Middle Bathonian of Bugaj, Polish Jura. A. NHM Bz 5612(1). A1, centre of cone−like subcolonies; A2, autozooidal apertures; A3, elongated and curved gonozooid.B. NHM BZ 5613, centre of cone−like subcolonies.C. NHM BZ 5614. C1, centre of flabellotrypiform colony; C2, pseudopores. Scale bars 300 µm (B), 200 µm (A1, A3, C1), 100 µm (A2), 20 µm (C2). BSE SEM images of uncoated specimens.

Fig. 1. A. Map of Poland with Jurassic deposits indicated (shaded areas) after removal of the Cenozoic cover. B. Geological map of the Polish Jura area with sampled localities indicated (asterisks). Adapted from Zatoń et al. 2006.

Fig. 2. Stomatoporid cyclostome bryozoans from the Middle Jurassic ore−bearing clays of the Polish Jura. A. Stomatopora bajocensis (d’Orbigny, 1850), Upper Bathonian, Ogrodzieniec, GIUS 8−3509−1. A1, autozooids showing high−angled bifurcations; A2, pseudopores. B. Stomatopora recurva Waagen, 1867, Middle Bathonian, Bugaj, GIUS 8−3509−2. B1, colony fragment showing early and later bifurcations; B2, pseudopores. C. Proboscinopora? sp., Middle Bathonian, Bugaj, GIUS 8−3509−7. C1, branching oligoserial colony, partly pyritised (white spots); C2, pseudopores. Scale bars: 300 µm (A1), 200 µm (B1, C1), 20 µm (A2, B2, C2). BSE SEM images of uncoated specimens.

Fig. 3. Oncousoeciid cyclostome bryozoan Microeciella annae sp. nov. from the Middle Jurassic ore−bearing clays of the Polish Jura. Holotype, GIUS 8−3509−8, Kawodrza Górna, Lower Bathonian. A. General colony view. B. Three gonozooids, one of which is aborted (arrow). C. Close−up of ooeciopore (arrow) and autozooids. D. Pseudopores. Scale bars 1000 µm (A), 100 µm (B), 100 µm (C), 20 µm (D). BSE SEM images of uncoated specimens.