Umbonula granulata, 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

Umbonula granulata sp. n.

Pl. 95, Fig. 1-6

D i a g n o s i s: Colony encrusting. Autozooecia rhomboidal with granular frontal wall. Marginal areolar pores small, about 10-15 on the border of each autozooecium. Aperture with a large lyrula. Avicularia of two types, small suboral and giant spatulate. No ovicell observed.

H o l o t y p e: The specimen illustrated in Pl. 95, Fig. 1 and 4-6, from the section Podbřežice, is deposited in the National Museum Prague under number PM2 – P 01903.

P a r a t y p e s: Altogether 4 specimens were studied from the locality Podbřežice, deposited in the National Museum Prague under numbers PM2 – P 01904-P 01907.

148

D e r i v a t i o n o m i n i s: Due to the granular frontal wall.

L o c u s t y p i c u s: section Podbřežice, sample Podbřežice village-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: (in micro meters = µm; x = = average):

length of autozooecia: 499-654; x = 614

width of autozooecia: 333-492; x = 396

length of autozooecial aperture: 152-231; x = 180

width of autozooecial aperture: 157-193; x = 176

length of suboral avicularium: 65-112; x = 85

width of suboral avicularium: 57-85; x = 72

length of spatulate avicularium: 275-299; x = 287

width of spatulate avicularium: 164-197; x = 181

diameter of areolar pore: 20-68; x = 48

D e s c r i p t i o n: Colony encrusting. Autozooecia rhomboidal with flat, granular frontal walls. Granules small, regularly arranged in quincuncial pattern. Marginal areolar pores small, there are about 10-15 pores on the bor- der of each autozooecium. Aperture large, oval with a large lyrula. Adventitious avicularia suboral or spatulate. Suboral avicularia with a pivotal bar (Pl. 95, Fig. 6); they are situat- ed on the middle of the frontal wall, proximally from the aperture, at the top of the umbo. The spatulate avicularia are giant, with an oval rostrum and a pivotal bar (Pl. 95, Fig. 3). No ovicell observed.

C o m p a r i s o n: This new species is very similar to Eschara chiragra Manzoni, 1877 in having a granular frontal wall, but it differs in having giant avicularia and encrusting colonies ( Eschara chiragra MANZONI, 1877 forms bilaminar colonies). Umbonula spinosa ( PROCHÁZKA, 1893) resembles this new species in having the “spines” similar to granules around the autozooecia. The granules are however much smaller than the tubercles on Umbonula spinosa ( PROCHÁZKA, 1893) . There are no ridges on the frontal wall as in Umbonula macrocheila ( REUSS, 1847) and the autozooecia in Umbonula granulata sp. n. are of a more rhomboidal shape.