Margaretta sp.

Zágoršek, Kamil & Gordon, Dennis P., 2013, Late Tortonian bryozoans from Mut Basin, Central Anatolian Plateau, southern Turkey, Acta Palaeontologica Polonica 58 (3), pp. 595-607 : 602

Margaretta sp.

Fig. 1F–J .

Referred material.—Altogether eight specimens were studied

(three of them illustrated ( Fig. 1F–H ) PM2−T1130 to PM2− T1132), mainly with highly developed secondary calcification. Description.—Colony columnar with branches of circular cross−section ( Fig. 1F ). Autozooecia arranged in 4–8 longitudinal rows, of indistinct shape owing to densely perforated slightly convex frontal wall ( Fig. 1F ). Secondary orifice circular to oval, no external peristome observed. Ascopore not observable from exterior. Ovicell deeply immersed, peristomial ( Fig. 1F ). Interior view shows regular small frontal pores ( Fig. 1G ) and median, circular, slightly larger ascopore ( Fig. 1G ); peristome consisting of 5–8 longitudinal bands separated by narrow, but distinct furrows ( Fig. 1G, H ). Ovicell not observed in interior view.

Remarks.— Margaretta cereoides ( Ellis and Solander, 1786) as described from the Miocene of Moravia by Zágoršek (2010b: 154, pl. 109: 1–4) does not have furrows in the peristomial wall fabric (visible in our Fig. 1J ), which may be considered a species−specific feature. However, a revision of the Margarettidae would be needed for a definite conclusion.

Figures

Fig. 1. Late Tortonian bryozoans from the Başyayla section. A. Exidmonea sp. (PM2−T1124) with very extended frontal gonozooecium from sample BAS 2. B–E. Biflustra savartii auctt. B. PM2−T1127, frontal view of colony, sample BAS 8. C. PM2−T1126, abfrontal view showing three rows of autozooecia with characteristic angled appearance, sample BAS 8. D. PM2−T1125, lateral view of the three autozooecia showing regularly distributed lateral communication pores, sample BAS 4. E. PM2−T1129, detail of lateral communication pores showing multiporous septula, sample BAS 4. F–H. Margaretta sp. F. PM2−T1130, external view showing concealed ovicells (visible as bulges in frontal shield), sample BAS 8. G. PM2−T1131, internal view showing peristomial chamber, with an ascopore situated in the midline of the frontal shield, sample BAS 11. H. PM2−T1132, detail of the aperture of a colony showing linear structures in the peristomial wall, sample BAS 7. I. Margaretta cereoides (Ellis and Solander, 1786) (PM2−P1939) from section Hlohovec (Moravia) showing the smooth interior surface of the peristome. Scale bars A, B, F, 1 mm; C–E, G–I, 100 µm.