Leioclema multiacanthoporum

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 : 712

Leioclema multiacanthoporum (Astrova in Astrova & Yaroshinskaya, 1968) ( Fig. 12 A-F; Appendix)

Lioclema multiacanthoporum Astrova in Astrova & Yaroshinskaya, 1968: 54, pl. 2, fig. 3. — Kopajevich 1984: 62, pl. 17, fig. 2.

MATERIAL. — SMF 21.221- SMF 21.226.

DESCRIPTION

Branched colonies, branches 1.8-3.1 mm in diameter, with 0.57-1.09 mm wide exozones and 0.66-0.92 mm wide endozones. Autozooecia budding from a thin epitheca, briefly oriented parallel to the substrate, then bending sharply and intersecting the colony surface at right angles. Autozooecial apertures rounded-polygonal to petaloid due to indenting acanthostyles. Autozooecial diaphragms rare to absent, thin, straight or slightly deflected proximally. Mesozooecia common, locally abundant, 2-5 surrounding each aperture, polygonal in cross section, slightly beaded, containing planar diaphragms. Acanthostyles moderately large, abundant, 4-9 surrounding each aperture, originating from the base of exozone, often indenting autozooecia, having distinct calcite cores and dark laminated sheaths. Walls granular, 0.010 -0.015 mm thick in endozones; distinctly laminated, 0.025 -0.065 mm thick in the exozone. Maculae not observed.

COMPARISON

Leioclema multiacanthoporum is similar to L.elegans Ernst, 2008 from the Lower Devonian of Prague Basin and NW-Spain (Ernst 2011), but differs from the latter in having more abundant acanthostyles (4-9 vs 3-6 in L. elegans ) and smaller distances between aperture centres ( 0.20 mm vs 0.26 mm in L. elegans on average).

The Spanish material described here is more similar to the original description of Astrova (Astrova & Yaroshinskaya 1968) than Mongolian material which differs in having thicker stems ( 5-10 mm vs 2-3 mm in material from Altai and Spain). Consequently, the Mongolian representatives of this species have a larger number of mesozooecia (4-9 vs 4-7 and 2-5 in Altai and Spanish material respectively).

Suborder AMPLEXOPORINA Astrova, 1965

Figures

FIG. 12. — A-F, Leioclema multiacanthoporum (Astrova in Astrova & Yaroshinskaya, 1968): A-C, branch oblique section showing autozooecia, mesozooecia and acanthostyles,SMF 21.225; D, branch transverse section, SMF 21.221; E, longitudinal section showing autozooecia and mesozooecia, SMF 21.222; F, tangential section showing autozooecial apertures, mesozooecia and acanthostyles, SMF 21.226; G-I, Eridotrypella validaeformis n. sp.: G, branch oblique section, paratype SMF 21.385; H, longitudinal section showing autozooecia with diaphragms, holotype SMF 21.227; I, tangential section showing autozooecial apertures and rare exilazooecia, holotype SMF 21.227. Scale bars: A-C, I, 1 mm; D, G, 2 mm; E, F, 0.2 mm; H, 0.5 mm.