Reptomultisparsa harae, Zatoń & Taylor, 2009

Zatoń, Michał & Taylor, Paul D., 2009, Middle Jurassic cyclostome bryozoans from the Polish Jura, Acta Palaeontologica Polonica 54 (2), pp. 267-288 : 278-279

Reptomultisparsa harae sp. nov.

Fig. 8 .

Etymology: In honour of Dr Urszula Hara, bryozoologist at the Polish Geological Institute, Warsaw.

Type material: Holotype: NHM D52832; paratype: GIUS 8−3509−16.

Type locality: Shipton Gorge , Dorset .

Type horizon: Inferior Oolite , Microzoa Beds (Upper Bajocian, Parkinsonia parkinsoni Zone ), Jurassic .

Material.— Holotype and one paratype listed above, the latter from the Middle Bathonian of Bugaj , Polish Jura.

Measurements.—FWL, 900–1260 µm; FWW, 240–260 µm; LAM, 160–200 µm; TAM, 120–160 µm; LPM, 220–260 µm; TPM, 180–220 µm; GTL, 2100–2400 µm; GDL, 1570–1620 µm; GW, 660–760 µm; OL, 190–215 µm; OW, 165–215 µm; PL, 12.5–17.5 µm; PW, 1.25–2.5 µm.

Diagnosis.— Reptomultisparsa with elongate ovoidal brood chamber, 2–3 × longer than wide, ooeciopore subcircular and about same diameter as an autozooidal aperture; autozooids large, about 250 µm wide; pseudopores slit−like.

Description.—Colony encrusting, sheet−like, multiserial, unilamellar, bereniciform. Early growth stages unknown.

Autozooids large, elongate with slightly convex frontal walls; zooidal boundaries well−marked, shallowly grooved. Preserved peristomes short, tapering distally. Apertures circular or longitudinally elliptical. Pseudopores slit−like, much longer than wide, densely spaced ( Fig. 8A 4, B 2 ).

Gonozooids common, well−preserved in the holotype ( Fig. 8A 1 , A 2 ) and crushed or aborted in the paratype ( Fig. 8B 1 ). Proximal frontal wall long, flat. Brood chamber convex, longitudinally elongated, ovoidal in shape, 2–3 × longer than wide, edges indented by apertures of neighbouring autozooids. Roof densely pseudoporous. Ooeciopore subterminal, circular or somewhat transversely elliptical, as large as an autozooidal aperture.

Remarks.—There are no significant differences between the holotype of this new species from the British Upper Bajocian and the paratype from the Polish Middle Bathonian. The two colonies have autozooids of similar size, the shape and size of the gonozooids is identical, and both have distinctive slit−like pseudopores. The type species of Reptomultisparsa , R. incrustans , has much larger gonozooids than R. harae and forms multilamellar colonies on gastropod shells inferred to have been occupied by hermit crabs (see Taylor 1994 and references therein). Many other Jurassic species assigned to this genus (e.g., R. walfordiana [ Canu and Bassler, 1922], R. cobra [ Pitt and Thomas, 1969], R. incrustans [d’Orbigny, 1850], and R. microstoma [Michelin, 1845]) have flatter colony surfaces, with more convex autozooidal frontal walls and brood chambers, as well as autozooidal apertures spaced widely apart relative to their diameters. The Polish Oxfordian species R. norberti Hara and Taylor, 1996 , differs from R. harae in having a gonozooid of low profile with a very wide ooeciopore.

Stratigraphic and geographic range.—Upper Bajocian of Shipton Gorge, Dorset, England, and Middle Bathonian of Bugaj, Polish Jura.

Figures

Fig. 8. Multisparsid cyclostome bryozoan Reptomultisparsa harae sp. nov. from the Middle Jurassic Inferior Oolite of England and ore−bearing clays of the Polish Jura. A. Holotype NHM D52832, Upper Bajocian, Shipton Gorge, Dorset, UK. A1, colony with gonozooids; A2, close−up of a gonozooid; A3, autozooids, some of which have terminal diaphragms; A4, pseudopores. B. Paratype, GIUS 8−3509−16, Middle Bathonian, Bugaj, Polish Jura. B1, autozooids and worn gonozooid; B2, pseudopores. Scale bars 1 mm (A1), 200 µm (A2), 100 µm (A3, B1), 20 µm (A4, B2). BSE SEM images of uncoated specimens.

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. 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.