Rhynchozoon HINCKS, 1895

ZÁGORŠEK, KAMIL, 2010, BRYOZOA FROM THE LANGHIAN (MIOCENE) OF THE CZECH REPUBLIC PART II: SYSTEMATIC DESCRIPTION OF THE SUBORDER ASCOPHORA LEVINSEN, 1909 AND PALEOECOLOGICAL RECONSTRUCTION OF THE STUDIED PALEOENVIRONMENT, Acta Musei Nationalis Pragae Series B 66 (3 - 4), pp. 139-255 : 139-255

Genus Rhynchozoon HINCKS, 1895

Colony encrusting, often multilamellar (growing in superimposed layers). Frontal wall convex, centrally imperforate with marginal areolar pores only. Aperture suborbicular to cleithridiate, primary orifice with a denticulate distal margin, sinus and condyles. Peristome with an asymmetrical pseudo-sinus and a suboral avicularium. Adventitious avicularia may be present. Ovicell prominent with nonporous frontal wall.

Rhynchozoon monoceros ( REUSS, 1847) Pl. 140, Fig. 1-6 v.* 1847 Cellepora monoceros m. – Reuss p. 80, Pl. 9, Fig. 24

1974 Umbonula monoceros (REUSS) – David and Pouyet p. 145, Pl. 12, Fig. 2

1977 Umbonula monoceros (REUSS) – Vávra p. 110 (cum syn.)

v. 1989 Umbonula monoceros (REUSS) – Schmid p. 32, Pl. 8, Fig. 5, 6 (cum syn.)

v. 2001 Umbonula monoceros (REUSS) – Zágoršek p. 54, 28, Fig. 7

v. 2003 Umbonula monoceros (REUSS) – Zágoršek p. 160 (cum syn.)

? 2006 Rhynchozoon monoceros (REUSS) – Berning p. 129, Fig. 169-172

T y p e: Holotype deposited in the Natural History Museum Vienna under the number 1847.38.73 ( Vávra, 1977)

M a t e r i a l: A very common species, 59 specimens from different sections were studied in detail.

D i a g n o s i s: Autozooecia with a drop-like shape, with a convex, granular frontal wall separated by distinct grooves. Marginal areolar pores rare and small. Aperture semicircular to oval with very small condyles. Peristome long, protruding above the aperture. Suboral avicularia small, circular with a pivotal bar, situated asymmetrically relative to the aperture. Two oral spines situated on the distal margin of the aperture. Adventitious avicularia absent. Ovicell prominent, globular, recumbent on the distal part of the autozooecium.

R e m a r k s: Berning (2006) described adventitious avicularia which are not present either in the types nor in the studied material, so it remains unclear whether his material also belongs to this species .

The presence of semicircular apertures, the asymmetrical position of avicularia and the small ovicells clearly affiliate this species to the genus Rhynchozoon .