Petalosis clarus, Ernst & Fernández & Fernández-Martínez & Vera, 2012

Ernst, Andrej, Fernández, Luis Pedro, Fernández-Martínez, Esperanza & Vera, Carmen, 2012, Description of a bryozoan fauna from mud mounds of the Lebanza Formation (Lower Devonian) in the Arauz area (Pisuerga-Carrión Province, Cantabrian Zone, NW Spain), Geodiversitas 34 (4), pp. 693-738 : 708

Petalosis clarus n. gen., n. sp. ( Figs 9 C-H, 10A-C; Appendix)

ETYMOLOGY. — The species name refers to the distinct morphology of the species (derived from Latin “ clarus ” = clear, distinct).

HOLOTYPE. — SMF 21.194 .

PARATYPES. — SMF 21.194- SMF 21.206.

TYPE LOCALITY. — Arauz Sur (Arroyo section), Province of Palencia, NW-Spain (Cantabrian Mountains).

TYPE HORIZON. — Lebanza Formation, Lower Devonian (Pragian).

DIAGNOSIS. — As for genus.

DESCRIPTION

Encrusting colonies, secondary overgrowths common. Encrusting sheets 0.8 to 3.3 mm in thickness. Autozooecia growing from thick epitheca, bending sharply at their bases towards colony surface. Autozooecial apertures circular to oval. Basal diaphragms common to moderately abundant, closely spaced, thin, horizontal or inclined. Lunaria well developed, laminated, prominent, horseshoe shaped to triangular, often containing 2-3 styles. One or two pairs of spine-like indentions occurring in lateral parts of proximal ends of autozooecia. Vesicles large and high, irregularly shaped, polygonal in tangential section, box-like to hemispherical, with plane or concave roofs, 3-8 surrounding each autozooecial aperture. Bands of large and irregularly shaped vesicles present. Acanthostyles between autozooecial apertures common, 0.0.25- 0.035 mm in diameter, having distinct hyaline cores and wide laminated sheaths. Autozooecial walls granular, 0.005 -0.010 thick in endozones; thick, laminated in exozones. Maculae not observed.

Order TREPOSTOMATA Ulrich, 1882 Suborder HALLOPORINA Astrova, 1965

Figures

FIG. 9. — A, B, Eridopora sp., tangential section showing autozooecial apertures with triangular lunaria, SMF 21.193; C-H, Petalosis clarus n. gen.n.sp.; C, longitudinal section showing autozooecia and vesicles,holotype SMF 21.194;D, E, transverse section showing lunaria, paratype SMF 21.200; F, tangential section, holotype SMF 21.194; G, H, tangential section showing autozooecial apertures with styles (arrows), paratype SMF 21.200. Scale bars: A, F, 1 mm; B, C, G, 0.2 mm; D, 0.5 mm; E, 0.25 mm; H, 0.1 mm.