Vidronovella elegantula, 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 : 718

Vidronovella elegantula n. sp. ( Figs 15 D-I; 16A, B; Appendix)

ETYMOLOGY. — The species name “ elegantula ” refers to the small size and general delicate appearance of the new species (derived from Latin “elegans” = elegant).

HOLOTYPE. — SMF 21.294 .

PARATYPES. — SMF 21.295- SMF 21.412.

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

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

DIAGNOSIS. — Branched colonies; bifurcation common; single superior and single inferior hemisepta well developed; paurostyles absent; 4-6 acanthostyles surrounding each autozooecial aperture; heterozooecia absent; mural spines absent.

DESCRIPTION

Branches 0.59-0.96 mm in diameter, with 0.23- 0.49 mm wide endozones and 0.16-0.26 mm wide exozones. Branch bifurcation common. Transverse sections of branches circular. Autozooecia short, budding from distinct medial axis in spiral order at angles of 45-60°. Autozooecial diaphragms absent. Superior hemiseptum moderately long, hook-shaped, curved proximally; inferior hemiseptum long, slender, occupying two-thirds of body cavity of autozooecia, positioned beneath superior hemisepta, inclined distally, widened laterally. Autozooecial apertures oval, arranged regularly in alternating rows on the colony surface. Walls in the endozone granular, 0.005 -0.010 mm thick; laminated in exozone. Acanthostyles having distinct hyaline cores and wide laminated sheaths, regularly sized, single or two positioned between two longitudinally successive autozooecial apertures, 4-6 surrounding each aperture. Acanthostyles often sealed by a thick layer of laminated skeleton on the colony surface. Mural spines absent.

COMPARISON

Vidronovella elegantula n. sp. differs from V. fastigiata Gorjunova, 2006 in having of 4-6 instead of 4 acanthostyles surrounding each autozooecial aperture, and from V. intricata Ernst, 2011 in the absence of mural spines and in the presence of single hemisepta instead of the double hemisepta found in V. intricata .

Figures

FIG. 15. — A-C, Orthopora spinosa n.sp.; A, branch transverse section showing autozooecia growing from distinct median axis,paratype SMF 21.258; B, C, tangential section showing apertures and acanthostyles, paratype SMF 21.268; D-I, Vidronovella elegantula n. sp.: D, branch oblique section, holotype SMF 21.294; E, F, tangential section showing autozooecial apertures and distribution of acanthostyles,holotype SMF 21.294;G, H, longitudinal section showing autozooecia with hemisepta, holotype SMF 21.294;I, branch transverse section showing autozooecia growing from distinct median axis, paratype SMF 21.312.Scale bars: A, C, E-G, 0.2 mm; B, H, I, 0.5 mm.