Hyporosopora aff. sauvagei ( Gregory, 1896 )

Zatoń, Michał & Taylor, Paul D., 2009, Middle Jurassic cyclostome bryozoans from the Polish Jura, Acta Palaeontologica Polonica 54 (2), pp. 267-288 : 283-284

Hyporosopora aff. sauvagei ( Gregory, 1896)

Fig. 13 .

Material.—Two colonies: GIUS 8−3509−22 and NHM BZ

5612(2). Measurements.—FWL, 716–816 µm; FWW, 266–283 µm;

LAM, 133–200 µm; TAM, 133–150 µm; LPM, 200–283 µm; TPM, 166–233 µm; GDL, 760–783 µm; GW, 1300–1450 µm; OL, 100–130 µm; OW, 100–116 µm; PL, 12.5–15 µm; PW, 10 µm.

Description.—Colony encrusting, sheet−like, multiserial, bereniciform, unilamellar, surface covered by transverse growth checks ( Fig. 13A 1 ).

Autozooids large, elongate, gently convex, zooidal boundaries distinct. Preserved peristomes short, tapering distally. Apertures circular to longitudinally elliptical, some closed by terminal diaphragms. Pseudopores densely spaced, teardrop−shaped, wide, pointed distally ( Fig. 13A 5 ).

Gonozooids present but crushed, one preserved in specimen NHM BZ 5612(2) and two in specimen GIUS 8−3509− 22. Proximal part flat. Brood chamber shape variable within same colony (GIUS 8−3509−22): much broader than long, boomerang−like ( Fig. 13A 3 ) or nearly equidimensional and heart−shaped with prominent distal lobes ( Fig. 13A 4). Roofs densely pseudoporous. Margins indented by neighbouring autozooidal apertures. Ooeciopore terminal, subcircular, much smaller than autozooidal aperture. Ooeciostome short, upright.

Remarks.—The material described here resembles the holotype (NHM B194) of Hyporosopora sauvagei from the Upper Bathonian Bradford Clay of Bradford on Avon, Wiltshire, England. However, the Polish material has teardrop−shaped pseudopores in contrast to those of the holotype which are transversely elongate and broadly U−shaped. Colonies of putative H. sauvagei from Balin also possess teardrop−shaped pseudopores ( Taylor 2009). However, in view of the importance for taxonomy of pseudopores shown by the current study, it is best to assign both the Balin and Bugaj material to H. aff. sauvagei .

Stratigraphic and geographic range.—Middle Bathonian of Bugaj, Polish Jura.

Figures

Fig. 13. Plagioeciid cyclostome bryozoan Hyporosopora aff. sauvagei (Gregory, 1896) from the Middle Jurassic ore−bearing clays of the Polish Jura. A. Middle Bathonian, Bugaj, GIUS 8−3509−22. A1, colony view; A2, autozooids; A3, boomerang−like gonozooid, ooeciopore arrowed; A4, heart−shaped gonozooid, ooeciopore arrowed; A5, pseudopores. B. Middle Bathonian, Bugaj, NHM BZ 5612(2), subtriangular gonozooid, ooeciopore arrowed. Scale bars: 1 mm (A1), 100 µm (A2–A4, B), 20 µm (A5). 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. 5. Oncousoeciid cyclostome bryozoan Microeciella maleckii sp. nov. from the Middle Jurassic ore−bearing clays of the Polish Jura. Holotype, GIUS 8−3509−13, Ogrodzieniec, Upper Bathonian. A. General colony view. B. Close−up of a gonozooid and autozooids.C. Close−up of a crushed gonozooid wit an ooeciopore preserved (arrowed). D. Pseudopores. Scale bars 200 µm (A), 100 µm (B, C), 20 µm (D). 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.