Orthopora spinosa, 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 : 716

Orthopora spinosa n. sp. ( Figs 14 G-I; 15A-C; Appendix)

HOLOTYPE. — SMF 21.254 .

PARATYPES. — SMF 21.255- SMF 21.293.

ETYMOLOGY. — The species name refers to the presence of abundant acanthostyles (derived from Latin “ spinosus ” – spiny).

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

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

DIAGNOSIS. — Branched colonies; bifurcations common; both superior and inferior hemisepta well developed; paurostyles absent; acanthostyles abundant, arranged in single row between autozooecia, varying in size.

DESCRIPTION

Branches 0.48-0.75 mm in diameter, with 0.19- 0.35 mm wide endozones and 0.14-0.22 mm wide exozones. Branch bifurcations common. Transverse sections of branches circular.Autozooecia short, growing in spiral pattern from the distinct median axis at angles of 35-51° in endozones, abruptly bending in exozones and intersecting colony surface at angles of 51-71°; having polygonal,tear-drop shape in transverse sections of endozone. Autozooecial diaphragms rare to absent. Long superior hemisepta present, curved proximally; inferior hemisepta long, positioned beneath superior hemisepta, curved distally.Autozooecial apertures oval, arranged regularly in alternating rows on the colony surface. Walls in the endozone granular, 0.005 -0.010 mm thick; in exozone laminated. Acanthostyles abundant, arranged in longitudinal rows between apertures, slightly varying in size, having narrow hyaline cores and wide laminated sheaths. Heterozooecia absent.

COMPARISON

Orthopora spinosa n. sp. is similar to O. sincera Ernst, 2011 from the Lower to Middle Devonian of NW Spain but differs in having thinner branches (average branch width 0.62 mm vs 0.74 mm in O. sincera ), and in the smaller and more widely spaced apertures (average aperture spacing along branch 0.28mm vs 0.36 mm in O. sincera ). Orthopora spinosa n. sp. differs from O. tenuis Ernst, 2008 in having smaller autozooecial apertures (average aperture width 0.050 mm vs 0.076 mm in O. tenuis ).

Figures

FIG.14.— A-F, Leptotrypella armata n.sp.: A, B, tangential section showing autozooecial apertures and acanthostyles,holotype SMF 21.238; C, tangential section showing autozooecial walls with abundant mural spines,paratype SMF 21.239;D, E, transverse section showing autozooecia with abundant diaphragms and autozooecial wall with mural spines,paratype SMF 21.239;F, longitudinal section,paratype SMF 21.252; G-I, Orthopora spinosa n. sp.; G, H, longitudinal section showing autozooecia with hemisepta, holotype SMF 21.254; I, tangential section showing autozooecial apertures and acanthostyles,holotype SMF 21.254.Scale bars:A-C,E, F,0.2 mm; D, G, H, 0.5 mm;I, 1 mm.