Argentinopora, 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 : 580-582

Genus Argentinopora n. gen.

urn:lsid:zoobank.org:act:54274BD8-98CF-4779-A8CD-D5A6CA3CC4F8

TYPE SPECIES. — Argentinopora robusta n. sp., by present designation.

DIAGNOSIS. — Ramose colonies with multiple secondary overgrowths; autozooecia tubular, shape of transverse section angular in endozone and rounded-angular in exozone; basal diaphragms common both in endozone and exozone; cystiphragms common in exozone;autozooecial apertures rounded-polygonal, often petaloid; 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; exozonal walls thickly laminated, merged, without cingulum; maculae not observed.

ETYMOLOGY. — The new genus is named after finding it in Argentina.

OCCURRENCE. — La Pola Formation, Upper Ordovician, Sandbian; Argentine Precordillera, western Argentina.

COMPARISON

The new genus is characterized by large acanthostyles with narrow sheaths, cystose mesozooecia and presence of cystiphragms. It shows some similarities to the Family Ralfimartitidae Gorjunova, 2005 . Gorjunova (2005) introduced the term “aulozooecia” for structures characteristic for Ralfimartitidae . The “aulozooecia” represent indeed large acanthostyles filled out by a hyaline skeletal material (see also Tavener-Smith 1969). The most similar genus in the Family Ralfimartitidae is Rozhnovites Gorjunova, 2005 which differs from Argentinopora in annulated arrangement of autozooecia and mesozooecia, as well as in absence of cystiphragms.