Jordanopora heroensis Ross, 1963

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 : 580

Jordanopora heroensis Ross, 1963

( Fig. 11 B-E; Appendix 1)

Jordanopora heroensis Ross, 1963a: 732 , pl. 105, figs 1-8, pl. 106, figs 1-4, 6, 7.

MATERIAL EXAMINED. — Single colony (three thin sections) CEGH-UNC 27530 e, f, g.

OCCURRENCE. — Chazy Series (Darriwilian-Sandbian) of New York, United States. La Pola Formation, Upper Ordovician, Sandbian; La Pola creek section near Albardon village, San Juan Province, Argentine Precordillera, western Argentina.

DESCRIPTION

Colony form uncertain in the present material,possibly branched (bifoliate?) with secondary overgrowth. Exozone distinct, 0.45 mm wide. Autozooecia prismatic, autozooecial apertures rounded-polygonal. Diaphragms thin, planar, widely spaced in exozones.Autozooecial walls 0.010 -0.015 mm thick, laminated, irregularly undulating in endozones; thickly laminated, without cingulum, broadly and irregularly serrated, 0.045 -0.110 mm thick in exozones. Tubules in exozonal walls abundant, surrounding apertures in one row, hyaline, oriented parallel to autozooecial growth, 0.02-0.05 mm in diameter.Mesozooecia rare to common, occasionally 1-3 surrounding autozooecial apertures,originating in endozone, containing thick diaphragms. Styles absent. Maculae not observed in the present material.

COMPARISON

The present material fits to the species Jordanopora heroensis Ross, 1963 in its morphology and dimensions.

Figures

FIG. 11. — A, Tarphophragma macrostoma (Loeblich, 1942), branch transverse thin section, CEGH-UNC 27539 a; B-E, Jordanopora heroensis Ross, 1963: B, C, oblique thin section trough the colony showing autozooecial chambers, CEGH-UNC 27530 f; D, E, tangential thin section showing autozooecial apertures, rare mesozooecia, and tubules in autozooecial walls, CEGH-UNC 27530 e; F, G, Argentinopora robusta n. gen., n. sp., holotype 27511 c, longitudinal section showing autozooecial chambers, mesozooecia, and acanthostyles. Scale bars: A, B, F, G, 1 mm; C, D, 0.5 mm; E, 0.2 mm.