Rhynchozoon oslavanensis, ZÁGORŠEK, 2010

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

Rhynchozoon oslavanensis sp. n.

Pl. 141, Fig. 1-2

D i a g n o s i s: Autozooeciahexagonal to oval, with a flat, smooth frontal wall. Marginal areolar pores prominent.. Aperture semilunar to oval with a fine denticulate distal margin. Peristomes short. Suboral avicularia large, drop-like with prominent pivotal bar. Oral spines paired. Adventitious avicularia absent. Ovicell flat, globular, recumbent.

H o l o t y p e: The specimen illustrated in Pl. 141, Fig. 1, from the section Oslavany, deposited in the National Museum Prague under the number PM2 – P 01807

P a r a t y p e: The specimen from the section Podbřežice, deposited in the National Museum Prague under the number PM2 – P 01808.

D e r i v a t i o n o m i n i s: Due to its occurrence in the section at Oslavany.

L o c u s t y p i c u s: Oslavany, sample OsII-1.

S t r a t u m t y p i c u m: Langhian – Lower Badenian.

M e a s u r e m e n t s:(inmicrometers=µm;x=average):

length of autozooecia: 466-505; x = 487

width of autozooecia: 383-394; x = 388

length of autozooecial aperture: 49-72; x = 60

width of autozooecial aperture: 120-154; x = 132

length of avicularium: 102-110; x = 106

width of avicularium: 73-100; x = 83

diameter of avicularium chamber: 206-227; x= 217

D e s c r i p t i o n: Autozooecia hexagonal to oval, with a flat, smooth frontal wall, separated by narrow grooves. Marginal areolar pores large, 14-16 at the border of each autozooecium. Aperture semilunar to oval with a fine denticulate distal margin. Peristome short. Suboral avicularia large, drop-like with prominent pivotal bar. Oral spines rare, usually two, situated on the distal margin of the aperture. Adventitious avicularia absent. Ovicell flat, large, globular, and slightly recumbent on the proximal part of the distal autozooecium.

C o m p a r i s o n: Differs from Rhynchozoon monoceros ( REUSS, 1847) in having large and abundant areolar pores and larger apertures and shorter peristomes bearing larger avicularia. Also the size of the ovicell in Rhynchozoon oslavanensis sp. n. is much larger than in Rhynchozoon monoceros ( REUSS, 1847)