Dyscritella leptosa, Ernst & Senowbari-Daryan & Hamedani, 2006

Ernst, Andrej, Senowbari-Daryan, Baba & Hamedani, Ali, 2006, Middle Permian Bryozoa from the Lakaftari area, northeast of Esfahan (central Iran), Geodiversitas 28 (4), pp. 543-590 : 550

Dyscritella leptosa n. sp. ( Fig. 4 A-E; Table 6)

HOLOTYPE. — SMF 2111 .

ETYMOLOGY. — The species name derives from Greek “λεπτος”: thin, and refers to the small thickness of encrusting colony.

PARATYPE. — 23-6-10.

TYPE LOCALITY. — Lakaftari, central Iran.

TYPE LEVEL. — Jamal Formation, Middle Permian.

ADDITIONAL MATERIAL EXAMINED. — 1-2-1, 1-2-2, 23-1-4.

OCCURRENCE. — Lakaftari: central Iran, Jamal Formation, Middle Permian.

DIAGNOSIS. — Thin encrusting colony with abundant exilazooecia, acanthostyles, and moderately thickened walls.

DESCRIPTION

Encrusting colonies, 0.16-0.24 mm thick (0.20 mm averagely). Autozooecia budding from a thin epitheca, on a short distance parallel to the substrate, then bending to the colony surface sharply. Autozooecial apertures polygonal, spaced 7-11 per 2 mm. Autozooecial diaphragms exceptionally rare (only one was observed), thin. Exilazooecia abundant, polygonal in cross section, often separating autozooecia. Acanthostyles abundant, 3-4 surrounding each aperture, having distinct calcite cores and dark, laminated sheaths. Walls granular, 5-10 µm thick in the endozone; distinctly laminated, 20-40 µm thick in the exozone. Maculae indistinct, consisting of larger autozooecia.

COMPARISON

Dyscritella leptosa n. sp. shows distinct characters of the genus Dyscritella : thickened walls, abundant exilazooecia and acanthostyles, as well as rare diaphragms. It differs from other species of the genus Dyscritella in having thin encrusting colony and closely spaced apertures.

Figures

FIG. 4. — A-E, Dyscritella leptosa n. sp.; A, SMF 2111, holotype, longitudinal section through the cylindrical colony; B, paratype 23- 6-10, cross section through the cylindrical colony; C, paratype 23-6-10, cross section through the encrusting colony; D, holotype 17-1-4, longitudinal section through the cylindrical colony;E, holotype 17-1-4, tangential section;F-H, J, Rectifenestella crassinodata n. sp.; F, SMF 2113,holotype,tangential section displaying apertures with apertural nodes;G, SMF 2113, holotype,tangential section displaying apertures and carinal nodes; H, 1-5-2, deep tangential section displaying autozooecia; J, 23-1-1, tangential section; I, K, L, Rectifenestella araxensis (Nikiforova,1933) n. comb.; I, 1-4-3, deep tangential section displaying autozooecia;K, 17-1-6, tangential section displaying apertures and carinal nodes; L, 1-4-1, deep tangential section. Scale bars: A, C, K, L, 0.5 mm; B, 1 mm; D, F, 0.2 mm; E, H, I, 0.1 mm; G, 0.25 mm; J, 2 mm