Microeciella maleckii, 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 : 274-275

Microeciella maleckii sp. nov.

Fig. 5 .

Etymology: In honour of the late Professor Jerzy Małecki, author of numerous papers on Polish fossil bryozoans.

Holotype: GIUS 8−3509−13.

Type locality: Ogrodzieniec, Polish Jura, Poland.

Type horizon: Ore−bearing Częstochowa Clay Formation, Upper Bathonian ( Procerites hodsoni Zone ), Jurassic.

Material.—One colony, the holotype.

Measurements.—FWL, 563–913 µm; FWW, 100–163 µm; LAM, 75–113 µm; TAM, 50–88 µm; LPM, 113–150 µm; TPM, 75–125 µm; GTL, 838 µm; GDL, 525–725 µm; GW, 513–700 µm; OL, 38 µm; OW, 50 µm; PL, 6.3–12.5 µm; PW, 5–6.3 µm.

Diagnosis.— Microeciella with ovoidal, bulbous brood chambers indented by autozooidal peristomes and subterminal, subcircular to slightly transverse ooeciopores; autozooids small, frontal walls less than 165 µm wide; pseudopores teardrop−shaped, pointed distally.

Description.—Colony encrusting, multiserial, unilamellar, bereniciform.

Autozooids small, elongate with slightly convex frontal walls; zooidal boundaries distinct, grooved. Peristomes tapering distally. Apertures subcircular to longitudinally elongated, some closed by terminal diaphragms. Pseudopores moderately spaced, teardrop−shaped, longer than wide, pointed distally ( Fig. 5D ).

Gonozooids partly or entirely crushed ( Fig. 5B, C ). Proximal frontal wall indistinguishable from an autozooid. Brood chamber ovoidal, only slightly longer than wide, with bulbous, convex frontal wall, outline indented by apertures of neighbouring autozooids, roof densely pseudoporous. Ooeciopore subterminal, smaller than an autozooidal aperture, subcircular or slightly transverse.

Remarks.—Cyclostomes having similar ovoidal, bulbous brood chambers with subterminal ooeciopore have been recently described by Viskova (2008) from the Middle Oxfordian of Russia under the name Hyporosopora mittai Viskova, 2008 . However, as the genus Hyporosopora is used for cyclostomes with subtriangular, boomerang−like or heart−shaped brood chambers, the species described by Viskova (2008) is better placed in Microeciella . The new species M. maleckii differs from M. mittai in having wider gonozooids, 713–700 µm compared to 370–400 µm in M. mittai . Differences between M. maleckii and other species of Microeciella described in the present study are evident from the species identification key (above).

Stratigraphic and geographic range.—Upper Bathonian of Ogrodzieniec, Polish Jura.

Figures

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.