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) Author Ernst, Andrej Author Fernández, Luis Pedro Author Fernández-Martínez, Esperanza Author Vera, Carmen text Geodiversitas 2012 2012-12-31 34 4 693 738 http://dx.doi.org/10.5252/g2012n4a1 journal article 10.5252/g2012n4a1 1638-9395 5380890 Petalosis n. gen. ETYMOLOGY. — The genus name refers to the petaloid shape of autozooecial apertures due to spine-like indentions. TYPE SPECIES . — Petalosis clarus n. sp. Lebanza Formation , Lower Devonian ( Pragian ) ; Arauz Sur (Arroyo section), Province of Palencia , NW-Spain ( Cantabrian Mountains ) . DIAGNOSIS. — Encrusting colonies with secondary overgrowths; autozooecial apertures circular to oval; autozooecia growing from thick epitheca, bending sharply at their bases towards colony surface; basal diaphragms common to abundant; lunaria well developed, prominent, horseshoe shaped to triangular, containing 2-3 styles; one or two pairs of spine-like indentions 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; bands of large and irregularly shaped vesicles occurring; acanthostyles between autozooecial apertures; autozooecial walls granular in endozones and laminated in exozones; maculae not observed. 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. COMPARISON Petalosis n. gen. differs from Fistuliporella Simpson, 1895 in having spine-like indentions in autozooecial apertures.