Argentinopora robusta, Ernst & Carrera, 2022

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 : 582

Argentinopora robusta n. gen., n. sp.

( Figs 11 F-G; 12A-F; Appendix 1)

urn:lsid:zoobank.org:act:51DCA703-84A9-4080-8A78-D507D5D6D0FC

HOLOTYPE. — CEGH-UNC 27511 a-d (one colony, four thin sections).

PARATYPES. — CEGH-UNC 27514 a-c, CEGH-UNC 27515 a, CEGH-UNC 27520 a, b.

TYPE LOCALITY. — La Pola creek section near Albardon village, San Juan Province, Argentine Precordillera, western Argentina.

TYPE HORIZON. — La Pola Formation, Upper Ordovician, Sandbian.

DIAGNOSIS. — As for genus.

ETYMOLOGY. — The species name refers to its thick walls and large mesozooecia and acanthostyles (from Latin “ robustus ” – robust, stable, strong).

DESCRIPTION

Ramose colony with multiple secondary overgrowths, 3.5- 11.0 mm in diameter, with 0.72.– 1.44 mm wide exozones. Secondary overgrowths 1.05-2.00 mm thick. Autozooecial apertures rounded-polygonal, often petaloid.Basal diaphragms abundant, straight or inclined throughout autozooecia.Cystiph - ragms common in exozones. Mesozooecia abundant, 3-7 surrounding each autozooecial aperture, originating in the early exozone, large, cystose, containing thick diaphragms. Acanthostyles large, abundant, 5-8 surrounding each autozooecial aperture, originating in endozone, having wide hyaline cores and narrow laminated sheaths, often indenting autozooecia and mesozooecia. Autozooecial walls laminated, 0.01-0.03 mm thick in endozones; thickly laminated, merged, without cingulum, 0.04-0.11 mm thick in exozones. Maculae not observed.

COMPARISON

As for genus.

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.