Orbitulipora excentrica Seguenza, 1880

Moissette, Pierre, Antonarakou, Assimina, Kontakiotis, George, Cornée, Jean-Jacques & Karakitsios, Vasileios, 2021, Bryozoan faunas at the Tortonian-Messinian transition. A palaeoenvironmental case study from Crete Island, eastern Mediterranean, Geodiversitas 43 (26), pp. 1365-1400 : 1387

Orbitulipora excentrica Seguenza, 1880

( Fig. 12 H-I)

Orbitulipora excentrica Seguenza, 1880: 130, pl. 12, figs 22-22a. — Neviani 1900: 188, pl. 17, figs 15-16. — Waters 1919: 90, text-fig. 2a-c. — Rosso & Sanfilippo 1991: 202, pl. 1, figs 1-5; pl. 2, figs 1-8. — Moissette et al. 1993: 113, figs a-c.

OCCURRENCE. — Late Eocene: Italy ( Waters 1919). Early Miocene: Sardinia ( Rosso & Sanfilippo 1991). Late Miocene: Calabria ( Rosso & Sanfilippo 1991), Crete ( Moissette et al. 1993). Orbitulipora and the orbituliporiform morphotype (fossil and Recent) are considered as deep-water markers and living representatives as typical of muddy bottoms ( Cook 1981; Rosso & Sanfilippo 1991).

DESCRIPTION

Discoidal bilaminar morphology (orbituliporiform). A short kenozooidal tube occurs at the apical part of each colony. Subcircular to subhexagonal zooids arranged in irregular concentric series and progressively increasing in size from the apex to the base. Frontal convex with relatively large pores. Very large circular aperture located in the centre of each zooid. No avicularia. A few ovicells (or their scars) are visible at the growing edge of some colonies. They are hyperstomial, spherical, as large as a zooid and perforated by pores similar to those of the zooecial frontal.

Figures

FIG. 12. — A-G, Batopora rosula (Reuss, 1847); A, colony, basal-lateral view (arrow indicates the scar of an ovicellate zooid), FAN7: AMPG(IV) 3475a; B, colony, apical view,FAN7:AMPG(IV) 3475b; C, colony,lateral-apical view, FAN7: AMPG(IV) 3475c; D-G, juvenile forms (G, basal view),FAN18: AMPG(IV)a-d; H-I, Orbitulipora excentrica Seguenza, 1880; H, whole colony, FAN22: AMPG(IV) 3580a; I, detail view of the left part of the same colony (arrows indicate ovicellate zooids), FAN22: AMPG(IV) 3580a. Scale bars: H, 500 µm; A-C, I, 200 µm; D-G, 100 µm.