Lunaferamita virginiensis Utgaard, 1981

Ernst, Andrej & Carrera, Marcelo G., 2022, A cool-water bryozoan association from the La Pola Formation (Sandbian, Ordovician) of Argentine Precordillera, Geodiversitas 44 (20), pp. 563-601 : 568

Lunaferamita virginiensis Utgaard, 1981

( Fig. 4 A-E; Appendix 1)

Lunaferamita virginiensis Utgaard, 1981: 1068-1070 , pl. 3, figs 1-9.

MATERIAL EXAMINED.— CEGH-UNC27506 a,b, CEGH-UNC27507 c, CEGH-UNC 27513 a-d, CEGH-UNC 27516c , CEGH-UNC 27520a,b , CEGH-UNC 27524 a,b, CEGH-UNC 27533 b, CEGH-UNC 27538 b.

OCCURRENCE. — La Pola Formation, Upper Ordovician, Sandbian; La Pola creek section near Albardon village, San Juan Province, Argentine Precordillera, western Argentina.

DESCRIPTION

Massive, encrusting, partly multilayered, or subramose colonies. Massive colony up to 20 mm in height, subramose extensions 3.8-5.0 mm in diameter. Autozooecia growing from thin epitheca, bending in the early exozone to the colony surface. Epitheca 0.003 -0.005 mm thick. Basal diaphragms abundant, straight or inclined, thin. Macrozooecia surrounding maculae, 0.14-0.22 mm wide. Autozooecial apertures circular to oval. Lunaria well-developed, rounded to slightly triangular,consisting of granular material; ends of lunaria not indenting autozooecia. Vesicles small to large, not completely separating autozooecia, arranged in 1-2 rows between apertures, 4-8 surrounding each autozooecial aperture, with rounded to flat roofs, polygonal in tangential section.Autozooecial walls granular prismatic, 0.005 - 0.020 mm thick. Colony surface covered by laminated stereom. Acanthostyles in stereom present, 0.015 -0.030 mm in diameter, more abundant in maculae.Maculae consisting of vesicular skeleton with larger vesicles,surrounded by macrozooecia, 0.67-1.25 mm in diameter, spaced 1.13-1.75 mm from centre to centre.

COMPARISON

Lunaferamita virginiensis Utgaard, 1981 differs from L. bassleri ( Loeblich, 1942) by having smaller autozooecia, less abundant acanthostyles and more abundant diaphragms. Lunaferamita virginiensis differs from L. vesicularis Chang, Yang & Xigiang, 2011 by having encrusting and massive colonies instead of ramose ones in the latter species.

Figures

FIG. 4. — A-E, Lunaferamita virginiensis Utgaard, 1981: A, longitudinal thin section of a colony, CEGH-UNC 27524 a; B, C, longitudinal section of exozone showing autozooecia with diaphragms and vesicles, CEGH-UNC 27513 c; D, tangential thin section showing macula, autozooecial apertures and acanthostyles (arrows), CEGH-UNC 27513 b; F, G, Xenotrypa argentinensis n. sp., longitudinal thin section, holotype CEGH-UNC 27523 b. Scale bars: A, F, 5 mm; B, D, 0.5 mm; C, E, 0.2 mm; G, 1 mm.