Microeciella sp.

Hara, Urszula & Taylor, Paul D., 2009, Cyclostome bryozoans from the Kimmeridgian (Upper Jurassic) of Poland, Geodiversitas 31 (3), pp. 555-575 : 564

Microeciella sp. ( Fig. 6 )

MATERIAL EXAMINED. — Skorków Lumachelle, Małogoszcz Quarry: NHM BZ 5520(3), BZ 5521. — Deltoideum Beds, Wierzbica Quarry NHM BZ 5515(1).

MEASUREMENTS. — Longitudinal apertural diameter = 0.08-0.10 mm; transverseaperturaldiameter = 0.06-0.08 mm; longitudinalperistomediameter = 0.11-0.12 mm; transverseperistome diameter = 0.08- 0.10 mm; frontal wall length = 0.40-0.70 mm; frontal wall width = 0.13-0.18 mm; gonozooid length = 0.45-0.47 mm; gonozooid width = 0.32-0.45 mm; ooeciopore length = 0.035 mm; ooeciopore width = 0.04 mm.

OCCURRENCE. — Lower Kimmeridgian, Wierzbica and Małogoszcz quarries, Holy Cross Mts, Poland.

DESCRIPTION

Colony encrusting, small, multiserial, growing as irregular fan-shaped lobes. Ancestrula not observed, early astogenetic zooids small, oligoserial.

Autozooidsslender, varying in length, boundaries well-defined, tapering somewhat distally; frontal wall with a fine transverse ornament. Apertures slightly longitudinally elongate, relatively small, some closed by terminal diaphragms. Peristomes narrow, longitudinally elongate, slightly acute. Pseudopores circular when corroded, about 10 µm in diameter.

Gonozooids numerous, generally located close to growing edge, slightly longer than wide or subcircular, proximal undilated frontal wall about as long as distal dilated frontal wall which is densely pseudoporous. Ooecioporesubterminal, smaller than autozooidal apertures, slightly transversely elongate or approximately circular; ooeciostome worn.

REMARKS

Microeciella was introduced by Taylor & Sequeiros (1982) for multiserial, discoidal to fan-shaped bereniciform tubuliporines possessing longitudinally ovoidal gonozooids (see also Taylor & McKinney 2006). It wasintended to accommodatespecies previously assigned in error to Microecia Canu, 1918 , whose type species ( Berenicea sarniensis Norman, 1864 ) isnowadays placed in Plagioecia Canu, 1918 . Soon after, Hayward & Ryland (1985) introduced Eurystrotos , based on the Recent type species Alecto compacta Norman, 1866 , for much the same reason. Taylor & Zaton (2008) have recently shown that Eurystrotos is a subjective junior synonym of Oncousoecia and differs from Microeciella in having branching, ribbon-like colonies.

The Polish Kimmeridgian species of Microeciella resembles the Toarcian typespecies M. beliensis from Spain, but the autozooids of the latter are longer and wider and the gonozooids are also longer. The same dimensions in the Polish species match reasonably well with those of two Middle Jurassic species from the Carmel Formation of Utah (see Taylor & Wilson 1999).Taking into account these quantitative characters, the greatest resemblance is with M. pollostos Taylor & Wilson, 1999 but a more detailed comparison between various species of Microeciella for the Polish material to be identified to species level.

Figures

FIG. 6. — Microeciella sp., Lower Kimmeridgian, Holy Cross Mts, Poland: A, B, NHM BZ 5521, Skorków Lumachelle, Małogoszcz Quarry; A, lobate branches; B, gonozooid with ooeciopore arrowed; C, NHM BZ 5520(3), Skorków Lumachelle, Małogoszcz Quarry, small fertile colony with two fan-like lobes;D-F, NHM BZ 5541(1),Deltoideum beds,Wierzbica Quarry;D, corroded autozooids;E, worn pseudopores; F, gonozooid with ooeciopore arrowed. Scale bars: A, C, 1 mm; B, D, 200 μm; E, 50 μm; F, 100 μm.