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Orbignyella multitabulata Coryell, 1921 (Fig. 6 E-G; Appendix 1) Orbignyella multitabulata Coryell, 1921: 284, pl. 5, figs 3-4. MATERIAL EXAMINED. — CEGH-UNC 27505 a-c, CEGH-UNC 27518 a-c. OCCURRENCE. — La Pola Formation, Upper Ordovician, Sandbian; La Pola creek section near Albardon village, San Juan Province, Argentine Precordillera, western Argentina. Pierce Limestone, Upper Ordovician (Sandbian); Tennessee, United States. DESCRIPTION Massive, subramose multilayered colonies. Secondary overgrowths common, 1-2 mm thick. Autozooecia bending gently from endozone, intersecting colony surface at right angles. Autozooecial apertures rounded to polygonal. Diaphragms in autozooecia common to abundant, straight to curved. Exilazooecia rare, polygonal in cross section, restricted to exozone. Acanthostyles common, moderately large, situated at junctions of autozooecial apertures. Autozooecial walls granular-prismatic, 0.005 -0.010 mm thick in endozone; irregularly thickened, finely laminated, displaying reverse V-structure in longitudinal section, 0.020 -0.033 mm thick in exozone. Maculae of macrozooecia 0.70-1.25 mm in diameter, spaced 1.9-2.0 mm from centre to centre. COMPARISON The present material is morphologically similar to Orbignyella multitabulata Coryell, 1921 from the Sandbian of United States. The only metric characteristic for O. multitabulata is the number of apertures per 2 mm given as 8-8.5 (Coryell 1921: 284). Interpolated, it gives apertural spacing of c. 0.23-0.25 mm what overlaps the range in the present species (0.13-0.22 mm). The present material differs from Orbignyella wetherbyi (Ulrich, 1890) from the Upper Ordovician of United States in smaller autozooecia (aperture width 0.11-0.19 mm vs 0.25-0.28 mm in O. wetherbyi)., Published as part of Ernst, Andrej & Carrera, Marcelo G., 2022, A cool-water bryozoan association from the La Pola Formation (Sandbian, Ordovician) of Argentine Precordillera, pp. 563-601 in Geodiversitas 44 (20) on page 572, DOI: 10.5252/geodiversitas2022v44a20, http://zenodo.org/record/6725916, {"references":["CORYELL H. N. 1921. - Bryozoan faunas of the Stone River Group of Central Tennessee. Proceedings of Indiana Academy of Sciences 1921: 261 - 340.","ULRICH E. O. 1890. - Palaeozoic Bryozoa: III. Report of the Geological Survey of Illinois 8: 283 - 688."]}

Dianulites rocklandensis Wilson, 1921 (Figs 5 F-G; 6A; Appendix 1) Dianulites rocklandensis Wilson, 1921: 47, pl. 2, figs 1-2. MATERIAL EXAMINED. — Single colony (three thin sections) CEGH-UNC 27503 a-c. OCCURRENCE. — La Pola Formation, Upper Ordovician, Sandbian; La Pola creek section near Albardon village, San Juan Province, Argentine Precordillera, western Argentina. Leray and Rockland formations, Upper Ordovician (Sandbian); Canada. DESCRIPTION Massive hemispherical colony, 8.5 mm thick in its central part and 20 mm wide at its base. Secondary overgrowth not observed. Exozone indistinct. Autozooecia long, prismatic, growing from epitheca. Autozooecial apertures polygonal. Diaphragms straight, rare to common in endozone, common in exozone. Autozooecial walls indistinctly granular, irregularly thickened, 0.015 -0.040 mm thick. Maculae not observed. COMPARISON The present material is similar to Dianulites rocklandensis Wilson, 1921 from the Ordovician (upper Sandbian) of Canada. This species, as described byWilson (1921), developed branched ramose colonies. However, Kang (2017) mentioned also hemispheric colonies of this species found at the type locality. Dianulites rocklandensis differs from D. microcellatus Astrova, 1945 from the Upper Ordovician of Urals in larger autozooecial apertures (0.24-0.36 mm vs 0.19-0.28 mm in D. microcellatus)., Published as part of Ernst, Andrej & Carrera, Marcelo G., 2022, A cool-water bryozoan association from the La Pola Formation (Sandbian, Ordovician) of Argentine Precordillera, pp. 563-601 in Geodiversitas 44 (20) on page 570, DOI: 10.5252/geodiversitas2022v44a20, http://zenodo.org/record/6725916, {"references":["WILSON A. E. 1921. - The range of certain Lower Ordovician faunas of the Ottawa Valley with descriptions of some new species. Canada Geological Survey Bulletin 33: 19 - 57. https: // doi. org / 10.4095 / 104998","KANG H. 2017. - Stratigraphy, Sedimentology, and Diagenesis of Ordovician Outliers, Northern Ottawa - Bonnechere Graben, Central Ontario. Master Thesis. Carleton University, Ottawa, Ontario, 284 p.","ASTROVA G. G. 1945. - Lower Silurian Trepostomata of the Kozhin River [in Russian]. Ezhegodnik Vsesoyuznogo Paleontologicheskogo Obshchestva 12: 81 - 92."]}

Homotrypa vacua McKinney, 1971 (Fig. 7 D-I; Appendix 1) Homotrypa vacua McKinney, 1971: 238-241, pl. 50, figs 2-7. — Pushkin 1987: 186. MATERIAL EXAMINED. — CEGH-UNC 27507 c, CEGH-UNC 27525 a, CEGH-UNC 27529 a, CEGH-UNC 27530 a, b, d-g, CEGH-UNC 27533 d, CEGH-UNC 27541 a, CEGH-UNC 27545 a. OCCURRENCE. — Lower Chickamauga Group, Upper Ordovician, Sandbian; Alabama, United States. La Pola Formation, Upper Ordovician, Sandbian; La Pola creek section near Albardon village, San Juan Province, Argentine Precordillera, western Argentina. DESCRIPTION Ramose colonies, branch diameter 1.45-2.38 mm. Endozone 0.60-1.45 mm wide, exozone 0.25-0.75 mm wide, distinct. Secondary overgrowths not observed. Autozooecia long in the endozone, having larger diameters than in exozone, bending gently and intersecting branch surface at low angles. Autozooecial apertures rounded-polygonal. Autozooecial diaphragms rare to absent in the endozone, concentrated mostly in transitional region between endo- and exozone, common to abundant in outer exozone.Cystiphragms occurring throughout the exozone, occupying about the half of autozooecial diameter. Mesozooecia locally 3-5 surrounding each autozooecial aperture, otherwise rare; small, short, restricted to the outermost part of exozone, containing densely spaced diaphragms. Acanthostyles common, 2-5 surrounding each autozooecial aperture, moderately large, restricted to exozone. Autozooecial walls straight, displaying granular microstructure, 0.003 -0.005 mm thick in endozone; finely laminated with indistinct medial line, 0.023 -0.055 mm thick in exozone. Indistinct maculae consisting of macrozooecia. COMPARISON Homotrypa vacua McKinney, 1971 differs from H. mundula (Ulrich, 1893) in having smaller colonies (branch diameter 1.45-2.38 mm vs 3.6-4.0 in H. mundula, measurements from Karklins [1984: 134]). Homotrypa vacua differs from H. subramosa Ulrich, 1886 in having thin branched colonies instead subramose and encrusting ones as well as in smaller autozooecial apertures (average aperture width 0.11 mm vs 0.16 mm in H. subramosa)., Published as part of Ernst, Andrej & Carrera, Marcelo G., 2022, A cool-water bryozoan association from the La Pola Formation (Sandbian, Ordovician) of Argentine Precordillera, pp. 563-601 in Geodiversitas 44 (20) on page 574, DOI: 10.5252/geodiversitas2022v44a20, http://zenodo.org/record/6725916, {"references":["MCKINNEY F. K. 1971. - Trepostomatous Ectoprocta (Bryozoa) from the lower Chickamauga Group (Middle Ordovician), Wills Valley, Alabama. Bulletins of American Paleontology 60: 195 - 333. https: // www. biodiversitylibrary. org / page / 28721254","PUSHKIN V. I. 1987. - Bryozoans of suborder Halloporina from Belorussia and East European Platform, in ROPOT V. P. & PUSHKIN V. I. (eds), Ordovician of Belarus. Nauka i Technika, Minsk: 145 - 232.","ULRICH E. O. 1893. - On Lower Silurian Bryozoa of Minnesota. The Geological and Natural History Survey of Minnesota, final report 3: 96 - 332. https: // doi. org / 10.5962 / bhl. title. 56338","KARKLINS O. L. 1984. - Trepostome and cystoporate bryozoans from the Lexington Limestone and the Clays Ferry Formation (Middle and Upper Ordovician) of Kentucky, in POJETA J. Jr. (ed.), Contributions to the Ordovician paleontology of Kentucky and nearby states. United States Geological Survey, Professional Paper 1066 I: I 1 - I 102. https: // doi. org / 10.3133 / pp 1066 I","ULRICH E. O. 1886. - Descriptions of new Silurian and Devonian fossils. Bryozoa. Contributions to American Palaeontology 1: 8 - 33. https: // doi. org / 10.5962 / bhl. title. 140012"]}

Diplotrypa sp. A (Fig. 9G; 10 A-D; Appendix 1) MATERIAL EXAMINED. — Single colony (two thin sections) CEGH-UNC 27543a, b. OCCURRENCE. — La Pola Formation, Upper Ordovician, Sandbian; La Pola creek section near Albardon village, San Juan Province, Argentine Precordillera, western Argentina. DESCRIPTION Massive colony, 6.2-6.4 mm in thickness, with indistinct endozone. Autozooecia growing from epitheca at high angles. Autozooecia in outer exozone often developing from mesozooecia. Autozooecial diaphragms common to rare, planar, curved proximally, irregularly spaced in autozooecia. Mesozooecia common, up to 3 surrounding each autozooecial aperture, bearing abundant straight diaphragms. Autozooecial walls fine fibrous microstructure, 0.005 -0.010 mm thick in endozone and 0.02-0.03 mm thick in exozone. COMPARISON Diplotrypa sp. A is similar to Diplotrypa catenulata Coryell, 1921 from the Sandbian of United States. Coryell [1921: 296] gave only the spacing of 4-4.5 apertures per 2 mm (distance from centre to centre 0.44-0.50 mm), which is more than double as large as the aperture spacing of the present material (average distance from centre to centre 0.22 mm). Size of apertures for Diplotrypa catenulata recorded by Astrova (1965: 185-186) from the Middle Ordovician of Arctic, was given as 0.42-0.75 mm (with macrozooecia of 0.9-1.0 mm width). Diplotrypa sp. A is similar to D. pusilla Astrova, 1965 from the Lower Ordovician of the Russian Arctic, but differs from it by less abundant diaphragms in autozooecia., Published as part of Ernst, Andrej & Carrera, Marcelo G., 2022, A cool-water bryozoan association from the La Pola Formation (Sandbian, Ordovician) of Argentine Precordillera, pp. 563-601 in Geodiversitas 44 (20) on page 578, DOI: 10.5252/geodiversitas2022v44a20, http://zenodo.org/record/6725916, {"references":["CORYELL H. N. 1921. - Bryozoan faunas of the Stone River Group of Central Tennessee. Proceedings of Indiana Academy of Sciences 1921: 261 - 340.","ASTROVA G. G. 1965. - Morphology, history of development and system of the Ordovician and Silurian Bryozoa. Trudy Paleontologicheskogo Instituta Akademii Nauk SSSR 106: 1 - 432 [in Russian]."]}

Genus Albardonia n. gen. urn:lsid:zoobank.org:act: CF51A226-FD7D-4583-B045-A26177B30FC0 TYPE SPECIES. — Albardonia bifoliata n. sp., by present designation. ETYMOLOGY. — The new genus is named after Albardon village near which this genus was found. DIAGNOSIS. — Ramose colony consisting of bifoliate fronds; encrusting sheets and secondary overgrowth common; autozooecia budding from mesotheca or epitheca, having angular shape of transverse section in endozone; autozooecial apertures angular with rounded corners; basal diaphragms common both in endozone and exozone, straight, or inclined; mesozooecia abundant, containing densely spaced diaphragms; aktinotostyles moderately large, abundant, originating in exozone, autozooecial walls laminated, integrated with dark median lining, showing reversal V-shaped lamination, without cingulum; maculae lacking. OCCURRENCE. — La Pola Formation, Upper Ordovician, Sandbian; Argentine Precordillera, western Argentina. COMPARISON The new genus is characterized by abundant mesozooecia and aktinotostyles. It is similar to the genus Leioclema Ulrich, 1882 in having abundant and large mesozooecia, but differs in the presence of aktinotostyles instead of acanthostyles in the latter genus., Published as part of Ernst, Andrej & Carrera, Marcelo G., 2022, A cool-water bryozoan association from the La Pola Formation (Sandbian, Ordovician) of Argentine Precordillera, pp. 563-601 in Geodiversitas 44 (20) on page 576, DOI: 10.5252/geodiversitas2022v44a20, http://zenodo.org/record/6725916, {"references":["ULRICH E. O. 1882. - American Palaeozoic Bryozoa. The Journal of the Cincinnati Society of Natural History 5: 121 - 175, 233 - 257."]}

Genus Parachasmatopora Morozova & Lavrentjeva, 1981 TYPE SPECIES. — Parachasmatopora maennili Morozova & Lavrentjeva, 1981 by original designation. Sandbian, Ordovician; Estonia. OCCURRENCE. — Middle-Upper Ordovician; United States, Estonia, Argentina. DIAGNOSIS. — Reticulated colonies consisting of anastomosing branches. Autozooecia long, having oblong-rectangular shape in deep tangential section, having weakly developed vestibule, arranged in two-three slightly alternating rows on branches. Nodes on low keels present. Cross-section of branches rounded; their dorsal wall thin, carrying thin longitudinal ribs and microacanthostyles. COMPARISON Parachasmatopora Morozova & Lavrentjeva, 1981 differs from Chasmatopora Eichwald, 1855 in having 2-3 rows of autozooecia on branches instead of 4 in Chasmatopora.

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.

Pseudostictoporella simplex n. sp. (Fig. 15 A-H; Appendix 1) urn:lsid:zoobank.org:act: 54CAAD81-853C-4879-BE5C-B78DCD98D7E9 HOLOTYPE. — CEGH-UNC 27508 a. PARATYPES. — CEGH-UNC 27528 b, CEGH-UNC 27530 e, f, g (three thin sections of one colony), CEGH-UNC 27533 a, b, c, d (four thin sections of one colony). 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. — Bifoliate branched colonies; mesotheca straight, median rods absent, autozooecia arranged in 10 to 20 regular alternating rows on branches; hemisepta absent; rare diaphragms occurring; metazooecia and styles absent; longitudinal ridges between autozooecial apertures. ETYMOLOGY. — The species name reflects the simple morphology defined by lacking of metazooecia and pustules (from Latin “ simplex ” – simple) DESCRIPTION Bifoliate branched colony. Branches 1.8-2.1 mm wide and 0.60-1.30 mm thick. Mesotheca straight, 0.015 to 0.045 mm thick, median rods absent. Autozooecia short, tubular, bending sharply to branch surface, rectangular at their bases, becoming oval at branch surface, arranged in 10 to 20 regular alternating rows on branches. Hemisepta absent. Rare diaphragms occurring. Metazooecia and styles absent. Autozooecial walls granular, 0.030 to 0.055 mm thick in endozone; thick, finely laminated in exozone. Extrazooecial skeleton well developed, consisting of laminated material. Longitudinal ridges between autozooecial apertures present. COMPARISON Pseudostictoporella simplex n. sp. is similar to P.typicalis Ross, 1970, but differs from it in absence of metazooecia and pustules. P. iberiensis Jiménez-Sánchez, 2009 from the Katian of Spain possesses hemisepta and may not belong to the genus Pseudostictoporella., Published as part of Ernst, Andrej & Carrera, Marcelo G., 2022, A cool-water bryozoan association from the La Pola Formation (Sandbian, Ordovician) of Argentine Precordillera, pp. 563-601 in Geodiversitas 44 (20) on pages 588-589, DOI: 10.5252/geodiversitas2022v44a20, http://zenodo.org/record/6725916, {"references":["ROSS J. R. P. 1970. - Distribution, paleoecology, and correlation of Champlainian Ectoprocta (Bryozoa), New York State, Part III. Journal of Paleontology 44: 346 - 382. https: // www. jstor. org / stable / 1302548"]}

Homotrypa subramosa Ulrich, 1886 (Fig. 7 A-C; Appendix 1) Homotrypa subramosa Ulrich, 1886: 81; 1893: 239-340, pl. 19, figs 21- 28. — Bassler 1911: 187-189, text-figs 99-100. — Bork & Perry 1968: 1053-1055, pl. 136, figs 1-3. — McKinney 1971: 234-237, pl. 49, fig. 4-8, pl. 50, fig. 1. — Marintsch 1998: 53-55, pl. 9, figs 1-5. Homotrypa insignis Ulrich, 1886: 82. MATERIAL EXAMINED. — CEGH-UNC 27516 a, d, CEGH-UNC 27519 a, b, CEGH-UNC 27530 a-g, CEGH-UNC 27531 b, CEGH-UNC 27536 a, CEGH-UNC 27537 a, b, CEGH-UNC 27542 a, c, d, e, CEGH-UNC 27545b. DESCRIPTION Irregularly branched, submassive or encrusting colony. Branches and fronds 5.6-9.4 mm thick, encrusting sheets 0.7-1.6 mm thick. Exozones indistinct. Autozooecia prismatic, growing for long distance along branch axis and bending gently to the colony surface. Autozooecial diaphragms common, thin, planar. Autozooecial apertures polygonal in tangential section. Cystiphragms abundant, densely spaced, constricting middle part of zooecia, about a half of their diameter. Mesozooecia few, polygonal. Autozooecial walls granular, 0.003 -0.005 mm thick in endozone; amalgamated, 0.02-0.03 mm thick in exozone. Acanthostyles few, small to moderate in size. Maculae consisting of macrozooecia, 0.80-0.95 mm in diameter. COMPARISON Homotrypa subramosa Ulrich, 1886 differs from H. callosa Ulrich, 1893 in larger autozooecial apertures (average aperture width 0.16 mm vs 0.14 mm in H. callosa; measurements for H.callosa from Marintsch, 1998). Homotrypa subramosa Ulrich, 1886 differs from H.tuberculata Ulrich, 1893 in less abundant and smaller acanthostyles and in smaller autozooecial apertures (average aperture width 0.16 mm vs 0.20 mm in H. tuberculata; measurements for H. tuberculata from Marintsch 1998)., Published as part of Ernst, Andrej & Carrera, Marcelo G., 2022, A cool-water bryozoan association from the La Pola Formation (Sandbian, Ordovician) of Argentine Precordillera, pp. 563-601 in Geodiversitas 44 (20) on pages 572-574, DOI: 10.5252/geodiversitas2022v44a20, http://zenodo.org/record/6725916, {"references":["ULRICH E. O. 1886. - Descriptions of new Silurian and Devonian fossils. Bryozoa. Contributions to American Palaeontology 1: 8 - 33. https: // doi. org / 10.5962 / bhl. title. 140012","ULRICH E. O. 1893. - On Lower Silurian Bryozoa of Minnesota. The Geological and Natural History Survey of Minnesota, final report 3: 96 - 332. https: // doi. org / 10.5962 / bhl. title. 56338","BASSLER R. S. 1911. - The early Paleozoic Bryozoa of the Baltic Provinces. Bulletin of the Smithsonian Institution, United States National Museum 77: 1 - 382. https: // hdl. handle. net / 10088 / 30445","BORK K. B. & PERRY T. G. 1968. - Bryozoa (Ectoprocta) of Champlainian age (Middle Ordovician) from northwestern Illinois and adjacent parts of Iowa and Wisconsin, Part III, Homotrypa, Orbignyella, Prasopora, Monticulipora and Cyphotrypa. Journal of Paleontology 42: 1042 - 1065. https: // www. jstor. org / stable / 1302188","MCKINNEY F. K. 1971. - Trepostomatous Ectoprocta (Bryozoa) from the lower Chickamauga Group (Middle Ordovician), Wills Valley, Alabama. Bulletins of American Paleontology 60: 195 - 333. https: // www. biodiversitylibrary. org / page / 28721254","MARINTSCH E. J. 1998. - Systematic paleontology, biostratigraphy, and paleoecology of Middle Ordovician Bryozoa (Trepostomata) from the Hermitage Formation of East-Central Tennessee. Bulletins of American Paleontology 112: 1 - 121. https: // www. biodiversitylibrary. org / page / 10673542","WILSON A. E. 1921. - The range of certain Lower Ordovician faunas of the Ottawa Valley with descriptions of some new species. Canada Geological Survey Bulletin 33: 19 - 57. https: // doi. org / 10.4095 / 104998","CORYELL H. N. 1921. - Bryozoan faunas of the Stone River Group of Central Tennessee. Proceedings of Indiana Academy of Sciences 1921: 261 - 340."]}

Genus Nicholsonella Ulrich, 1890 TYPE SPECIES. — Nicholsonella ponderosa Ulrich, 1890 by original designation,Trentonian, Sandbian, Upper Ordovician, North America. DIAGNOSIS. — Encrusting, frondose, ramose, less commonly massive colonies. Apertures rounded and irregularly petaloid. Walls structureless, very thin, irregularly thickened in different part of colonies. Diaphragms usually abundant in whole colony, more rarely – only in the exozone. Mesozooecia abundant, containing frequent diaphragms, sometimes beaded, irregularly closed by calcitic material on the colony surface. Acanthostyles usually small, abundant, short, restricted to the outermost exozone. OCCURRENCE. — Lower Ordovician to Lower Silurian of North America and Siberia. COMPARISON Nicholsonella Ulrich, 1890 and some other genera (e.g. Dianulites) are unique among trepostome bryozoans by their re-crystallized walls which suggest a diagenetically unstable aragonitic (McKinney 1971) or high Mg calcite composition (Taylor & Wilson 1999)., Published as part of Ernst, Andrej & Carrera, Marcelo G., 2022, A cool-water bryozoan association from the La Pola Formation (Sandbian, Ordovician) of Argentine Precordillera, pp. 563-601 in Geodiversitas 44 (20) on page 582, DOI: 10.5252/geodiversitas2022v44a20, http://zenodo.org/record/6725916, {"references":["ULRICH E. O. 1890. - Palaeozoic Bryozoa: III. Report of the Geological Survey of Illinois 8: 283 - 688.","MCKINNEY F. K. 1971. - Trepostomatous Ectoprocta (Bryozoa) from the lower Chickamauga Group (Middle Ordovician), Wills Valley, Alabama. Bulletins of American Paleontology 60: 195 - 333. https: // www. biodiversitylibrary. org / page / 28721254","TAYLOR P. D. & WILSON M. A. 1999. - Dianulites Eichwald, 1829: an unusual Ordovician bryozoan with a high- magnesium calcite skeleton. Journal of Paleontology 73: 38 - 48. https: // doi. org / 10.1017 / S 0022336000027529"]}

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., Published as part of Ernst, Andrej & Carrera, Marcelo G., 2022, A cool-water bryozoan association from the La Pola Formation (Sandbian, Ordovician) of Argentine Precordillera, pp. 563-601 in Geodiversitas 44 (20) on page 568, DOI: 10.5252/geodiversitas2022v44a20, http://zenodo.org/record/6725916, {"references":["UTGAARD J. 1981. - Lunaferamita, a new genus of Constellariidae (Bryozoa) with strong cystoporate affinities. Journal of Paleontology 55 (5): 1058 - 1070. https: // www. jstor. org / stable / 1304530","LOEBLICH A. 1942. - Bryozoa from the Ordovician Bromide Formation, Oklahoma. Journal of Paleontology 16: 413 - 436. https: // www. jstor. org / stable / 1298838","CHANG Y., YANG D. & XIGIANG W. 2011. - Bryozoans (Cystoporida, Cryptostomida and Fenestrida) from the cores of the Lianglitag Formation (Upper Ordovician) in the central and northern Tarim Basin, Xinjiang, NW China. Acta Micropalaeontologica Sinica 28 (4): 411 - 428."]}

Monticulipora aff. mammulata d’Orbigny, 1850 (Fig. 6 B-D; Appendix 1) For full synonymy of the species Monticulipora mammulata d’Orbigny, 1850, see in Brown & Daly (1985: 68). MATERIAL EXAMINED. — Single colony (three thin sections) CEGH-UNC 27516 a, b, d. OCCURRENCE. — La Pola Formation, Upper Ordovician, Sandbian; La Pola creek section near Albardon village, San Juan Province, Argentine Precordillera, western Argentina. DESCRIPTION Submassive colony, multilayered, weakly differentiated into exo- and endozone. Autozooecia prismatic, bearing abundant cystiphragms.Autozooecial diaphragms common to abundant, mainly inclined or cystoid. Autozooecial apertures polygonal. Mesozooecia common, polygonal in tangential section, bearing closely spaced diaphragms, locally beaded. Zooecial walls laminated, serrated, 0.01-0.02 mm thick. Acanthostyles rare, 0.030 -0.035 mm in diameter. Maculae not observed. COMPARISON The present material is similar to Monticulipora mammulata d’Orbigny, 1850 from the Upper Ordovician of North America. However, the typical monticules consisting of abundant mesozooecia, were not found in the present material. Monticulipora parallela McKinney, 1971 from the Middle Ordovician of United States (Alabama) differs from the present material in encrusting colony and larger autozooecial apertures (average aperture width 0.20 mm vs 0.18 mm in the present material)., Published as part of Ernst, Andrej & Carrera, Marcelo G., 2022, A cool-water bryozoan association from the La Pola Formation (Sandbian, Ordovician) of Argentine Precordillera, pp. 563-601 in Geodiversitas 44 (20) on pages 570-572, DOI: 10.5252/geodiversitas2022v44a20, http://zenodo.org/record/6725916, {"references":["BROWN G. D. JR & DALY E. J. 1985. - Trepostome Bryozoa from the Dillsboro Formation (Cincinnatian Series) of Southeastern Indiana. Indiana Geological Survey Special Report 33: 1 - 95. https: // doi. org / 10.5967 / be 7 p-p 337","WILSON A. E. 1921. - The range of certain Lower Ordovician faunas of the Ottawa Valley with descriptions of some new species. Canada Geological Survey Bulletin 33: 19 - 57. https: // doi. org / 10.4095 / 104998","MCKINNEY F. K. 1971. - Trepostomatous Ectoprocta (Bryozoa) from the lower Chickamauga Group (Middle Ordovician), Wills Valley, Alabama. Bulletins of American Paleontology 60: 195 - 333. https: // www. biodiversitylibrary. org / page / 28721254"]}

Genus Diplotrypa Nicholson, 1879 TYPE SPECIES. — Monticulipora (Diplotrypa) petropolitana Nicholson, 1879 by original designation (non Favosites petropolitanus Pander, 1830). Sweden; Middle Ordovician. DIAGNOSIS. — Massive, variably shaped colonies, exozone poorly developed. Budding pattern interzooecial. Zooecial arrangement disordered; zooecia gradually expand distally through early ontogeny and curve outward toward colony surface; zooecia characterised by ontogenetic progression of mesozooecia expanding into autozooecia. Mesozooecial stage of early zooecial ontogeny extended; after mesozooecial stage, diaphragms widely spaced in proximal ends and closely spaced in distal ends of mesozooecia; mesozooecia occasionally fuse to form autozooecia; mesozooecia commonly isolate autozooecia. Autozooecial apertures polygonal to rounded. Autozooecial walls commonly thin throughout colony and composed of finely crystalline microlaminae. Diaphragms thin, planar, concave, convex or cystoidal, variably spaced. Acanthostyles rare. Maculae usually consisting of macrozooecia. OCCURRENCE. — Lower Ordovician to Upper Silurian; North America, Asia, and Europe. COMPARISON Diplotrypa Nicholson, 1879 differs from other genera of the Family Halloporidae by its massive colony form and thin zooecial walls., Published as part of Ernst, Andrej & Carrera, Marcelo G., 2022, A cool-water bryozoan association from the La Pola Formation (Sandbian, Ordovician) of Argentine Precordillera, pp. 563-601 in Geodiversitas 44 (20) on page 578, DOI: 10.5252/geodiversitas2022v44a20, http://zenodo.org/record/6725916, {"references":["NICHOLSON H. A. 1879. - On the Structure and Affinities of the \" Tabulate Corals \" of the Paleozoic Period, with Critical Descriptions of Illustrative Species. 15 pls, 44 text-figs. William Blackwood and Sons, Edinburgh, 342 p. https: // doi. org / 10.5962 / bhl. title. 9117","PANDER C. H. 1830. - Beitrage zur Geognosie des russischen Reiches. K. Kray, St. Petersburg, 165 p. https: // doi. org / 10.3931 / e-rara- 39166"]}

Ernst, Andrej, Carrera, Marcelo G. (2022): A cool-water bryozoan association from the La Pola Formation (Sandbian, Ordovician) of Argentine Precordillera. Geodiversitas 44 (20): 563-601, DOI: 10.5252/geodiversitas2022v44a20

Genus Pseudostictoporella Ross, 1970 TYPE SPECIES. — Pseudostictoporella typicalis Ross, 1970 by original designation. Rockland Formation, Selby Member (P. bicornis Biozone), Sandbian, Ordovician; Ontario, Canada and New York, United States. DIAGNOSIS. — Colonies bifoliate, bifurcating. Autozooecia subelliptical in cross section in the endozone; irregularly hexagonal in cross section in exozone; partly separated by exilazooecia. Autozooecial diaphragms rare to absent. Hemisepta absent. Pustules common along autozooecial boundaries, scattered in exozonal walls. Metazooecia polygonal to irregularly subcircular, arranged in groups, singly or in short rows. Monticules common, generally flat; consisting of metazooecia, few autozooecia and some skeletal material. OCCURRENCE. — Sandbian, Upper Ordovician; Canada, United States, Argentina. COMPARISON The genus Pseudostictoporella Ross, 1970 differs from the genus Stictoporella Ulrich 1882 by the absence of hemisepta, from the genera Oanduella Männil, 1958 and Stictoporellina Nekhoroshev, 1956 – by bifurcating colony shape instead of reticulate one in the latter genera., Published as part of Ernst, Andrej & Carrera, Marcelo G., 2022, A cool-water bryozoan association from the La Pola Formation (Sandbian, Ordovician) of Argentine Precordillera, pp. 563-601 in Geodiversitas 44 (20) on page 588, DOI: 10.5252/geodiversitas2022v44a20, http://zenodo.org/record/6725916, {"references":["ROSS J. R. P. 1970. - Distribution, paleoecology, and correlation of Champlainian Ectoprocta (Bryozoa), New York State, Part III. Journal of Paleontology 44: 346 - 382. https: // www. jstor. org / stable / 1302548","ULRICH E. O. 1882. - American Palaeozoic Bryozoa. The Journal of the Cincinnati Society of Natural History 5: 121 - 175, 233 - 257.","MANNIL R. M. 1958. - New bryozoans of the order Cryptostomata from Ordovician of Estonia. Eesti NSV Teaduste Akadeemia Toimetised, Tehniliste ja fuusikalis-matemaatiliste teaduste seeria 7 (4): 330 - 347 [in Russian]. https: // doi. org / 10.3176 / tech. phys. math. 1958.4.07","NEKHOROSHEV V. P. 1956. - Class Bryozoa. Trudy VSEGEI 12: 42 - 49 [in Russian]."]}

Genus Trigonodictya Ulrich, 1893 Trigonodictya Ulrich, 1893: 160. Astreptodictya Karklins, 1969: 49. Trigonodictya (Astreptodictya) – Karklins 1983b: 513. TYPE SPECIES. — Pachydictya conciliatrix Ulrich, 1886 by subsequent designation (Ulrich 1893). Decorah Shale, Middle Ordovician; United States (Minnesota). DIAGNOSIS. — Branched colonies, sometimes with lateral ridgelike expansions. Mesotheca straight to sinuous in longitudinal section, locally zigzag in transverse section, containing median rods. Autozooecia arranged in straight rows, subrectangular to subrhomboidal in transversal section of endozone, locally separated by extrazooecial vesicles in endozone, separated by extrazooecial stereom in exozone, rectangular in deep tangential section, becoming oval on the colony surface. Basal diaphragms straight to slightly curved. Extrazooecial skeletal deposits common, consisting of laminar and vesicular portions. Vesicular structures common in inner exozones, locally in endozones. Laminar stereom commonly with dark zones, longitudinally aligned, locally with indistinct mural styles. Autozooecial boundaries distinct, delineated laterally by continuous dark zones. Monticules absent. OCCURRENCE. — Middle Ordovician – Middle Silurian; Europe, North and South America. COMPARISON Trigonodictya Ulrich, 1893 differs from Pachydictya Ulrich, 1882 in regular arrangement of autozooecia in straight rows., Published as part of Ernst, Andrej & Carrera, Marcelo G., 2022, A cool-water bryozoan association from the La Pola Formation (Sandbian, Ordovician) of Argentine Precordillera, pp. 563-601 in Geodiversitas 44 (20) on page 586, DOI: 10.5252/geodiversitas2022v44a20, http://zenodo.org/record/6725916, {"references":["ULRICH E. O. 1893. - On Lower Silurian Bryozoa of Minnesota. The Geological and Natural History Survey of Minnesota, final report 3: 96 - 332. https: // doi. org / 10.5962 / bhl. title. 56338","KARKLINS O. L. 1969. - The cryptostome Bryozoa from the Middle Ordovician Decorah Shale, Minnesota. Minnesota Geological Survey Special Publication 6: 1 - 121. https: // hdl. handle. net / 11299 / 59956","KARKLINS O. L. 1983 b. - Systematic descriptions for the Suborder Ptilodictyina, in ROBISON R. A. (ed.), Treatise on Invertebrate Paleontology. Part G (1). Bryozoa (revised). Geological Society of America and University of Kansas Press, Boulder: 489 - 529.","ULRICH E. O. 1886. - Descriptions of new Silurian and Devonian fossils. Bryozoa. Contributions to American Palaeontology 1: 8 - 33. https: // doi. org / 10.5962 / bhl. title. 140012","ULRICH E. O. 1882. - American Palaeozoic Bryozoa. The Journal of the Cincinnati Society of Natural History 5: 121 - 175, 233 - 257."]}

Tarphophragma macrostoma (Loeblich, 1942) (Figs 10 E-G; 11A; Appendix 1) Hallopora macrostoma Loeblich, 1942: 430, pl. 62, figs 12-14. Tarphophragma macrostoma – Key 1991: 207-209, figs 6.1-6.6. MATERIAL EXAMINED. — CEGH-UNC 27520 c, d, CEGH-UNC 27539 c, d, g, CEGH-UNC 27537 d, CEGH-UNC 27538 d. OCCURRENCE. — Bromide Formation, Upper Ordovician, lower Sandbian; Oklahoma, United States. La Pola Formation, Upper Ordovician, Sandbian; La Pola creek section near Albardon village, San Juan Province, Argentine Precordillera, western Argentina. DESCRIPTION Ramose colonies, branch diameter 3.0- 3.6 mm. Exozone distinct, 0.5-0.6 mm wide, endozone 2.0- 2.4 mm wide. Autozooecia long, growing parallel to branch axis for a long distance in endozone and bending sharply in exozone, having rounded-polygonal shape in transverse section in endozone. Autozooecial apertures oval to polygonal. Autozooecial diaphragms thin, planar, widely spaced in endozone; common to abundant in exozone, planar, rarely inclined, developed as extension of wall cortex. Mesozooecia arising in endozone, polygonal in transverse section, 2-6 surrounding each autozooecial aperture. Mesozooecial diaphragms planar, densely spaced. Acanthostyles absent. Autozooecial walls indistinctly laminated, 0.005 -0.008 mm thick in endozone; displaying distinct reverse V-shaped structure with dark autozooecial boundary, with weakly developed wall cortex continued in diaphragms, 0.04-0.12 mm thick in exozone. Maculae indistinct, consisting of macrozooecia. COMPARISON Tarphophragma macrostoma (Loeblich, 1942) differs from T. ovata (McKinney, 1971) from the Middle Ordovician of United States in larger autozooecial apertures (average aperture width 0.21 mm vs 0.17 mm in T. ovata; measurements for T. ovata from McKinney 1971), as well as in less abundant and smaller mesozooecia. Tarphophragma macrostoma differs from T. multitabulata (Ulrich, 1886) from the Middle Ordovician of United States in larger autozooecial apertures (average aperture width 0.21 mm vs 0.19 mm in T. multitabulata; measurements for T. multitabulata from Karklins 1984)., Published as part of Ernst, Andrej & Carrera, Marcelo G., 2022, A cool-water bryozoan association from the La Pola Formation (Sandbian, Ordovician) of Argentine Precordillera, pp. 563-601 in Geodiversitas 44 (20) on page 580, DOI: 10.5252/geodiversitas2022v44a20, http://zenodo.org/record/6725916, {"references":["LOEBLICH A. 1942. - Bryozoa from the Ordovician Bromide Formation, Oklahoma. Journal of Paleontology 16: 413 - 436. https: // www. jstor. org / stable / 1298838","KEY M. M. JR 1991. - The halloporid trepostome bryozoans from the Ordovician Simpson Group of Oklahoma. Journal of Paleontology 65: 200 - 212. https: // doi. org / 10.1017 / S 0022336000020436","MCKINNEY F. K. 1971. - Trepostomatous Ectoprocta (Bryozoa) from the lower Chickamauga Group (Middle Ordovician), Wills Valley, Alabama. Bulletins of American Paleontology 60: 195 - 333. https: // www. biodiversitylibrary. org / page / 28721254","ULRICH E. O. 1886. - Descriptions of new Silurian and Devonian fossils. Bryozoa. Contributions to American Palaeontology 1: 8 - 33. https: // doi. org / 10.5962 / bhl. title. 140012","KARKLINS O. L. 1984. - Trepostome and cystoporate bryozoans from the Lexington Limestone and the Clays Ferry Formation (Middle and Upper Ordovician) of Kentucky, in POJETA J. Jr. (ed.), Contributions to the Ordovician paleontology of Kentucky and nearby states. United States Geological Survey, Professional Paper 1066 I: I 1 - I 102. https: // doi. org / 10.3133 / pp 1066 I"]}

Albardonia bifoliata n. gen., n. sp. (Figs 8G, H; 9 A-F; Appendix 1) urn:lsid:zoobank.org:act: 8C45367C-9280-4982-A6C2-9E757EFFD061 HOLOTYPE. — CEGH-UNC 27538 c. PARATYPES. — CEGH-UNC 27507 a, b, CEGH-UNC 27520 a, b, d, CEGH-UNC 27528 a, CEGH-UNC 27529 a, CEGH-UNC 27530 a, b, e, f, g, CEGH-UNC 27532 a, CEGH-UNC 27533 a, b, CEGH-UNC 27537 b, CEGH-UNC 27538 a, b, CEGH-UNC 27539 b, CEGH-UNC 27541 a (in total, 19 thin sections of 10 colonies). 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 the bifoliate colony shape of the new species. DESCRIPTION Bifoliate (frondose) colony starting from encrusting sheets. Fronds 0.70-1.30 mm in thickness. Encrusting sheets 0.66- 1.31 mm thick. Secondary overgrowths occurring. Autozooecia budding from mesotheca, having angular shape of transverse section in endozone. Autozooecial apertures angular with rounded corners. Mesotheca 0.01-0.02 mm in thickness. Basal diaphragms common both in endozone and exozone, straight, or inclined. Mesozooecia abundant, 3-8 surrounding each autozooecial aperture, containing densely spaced diaphragms. Aktinotostyles moderately large, abundant, 5-7 surrounding each autozooecial aperture, originating in the outer exozone. Autozooecial walls granular, 0.010 -0.015 mm thick, irregularly undulating in endozones; laminated, integrated with dark median lining, showing reversal V-shaped lamination, without cingulum, 0.02-0.05 mm thick in exozones. Maculae not observed. COMPARISON As for genus., Published as part of Ernst, Andrej & Carrera, Marcelo G., 2022, A cool-water bryozoan association from the La Pola Formation (Sandbian, Ordovician) of Argentine Precordillera, pp. 563-601 in Geodiversitas 44 (20) on pages 576-578, DOI: 10.5252/geodiversitas2022v44a20, http://zenodo.org/record/6725916

Parachasmatopora sp. A (Figs 16G; 17 A-E) MATERIAL EXAMINED. — CEGH-UNC 27526 a, CEGH-UNC 27529 b, CEGH-UNC 27533 a, CEGH-UNC 27545 a, b. OCCURRENCE. — La Pola Formation, Upper Ordovician, Sandbian; La Pola creek section near Albardon village, San Juan Province, Argentine Precordillera, western Argentina. DESCRIPTION Exterior Reticulate colonies consisting of regularly anastomosing branches. Branches rounded in cross section, 0.25-0.47 mm wide and 0.30-0.50 mm thick. Fenestrules elliptical, 0.22- 0.30 mm wide and 0.43-0.91 mm long. Autozooecial apertures rounded to oval, arranged in two alternating rows on branches, 3-4 in each fenestrule length, 0.05-0.09 mm in width.Low keel between autozooecial aperture rows carrying small elliptical nodes. Heterozooecia absent. Microstylets occurring both on reverse and obverse sides of colony, 0.02-0.03 mm in diameter. Interior Autozooecia long, rectangular in deep tangential section, occasionally having abundant diaphragms. Vestibule short. Hemisepta absent.Inner granular skeleton hyaline, 0.005 -0.008 mm thick. Outer lamellar skeleton usually well-developed on both obverse and reverse sides of colony, 0.075 - 0.040 mm thick. COMPARISON Parachasmatopora sp. A species differs from Parachasmatopora maennili Morozova & Lavrentjeva, 1981 in smaller autozooecial apertures (0.05-0.09 mm vs 0.10-0.12 mm in P. maennili). Superficially, Parachasmatopora sp. Ais similar to Parachasmatopora typicalis (Bassler, 1952). However, the latter species was only externally figured (Bassler 1952: figs 8-9). Therefore, a detailed comparison is impossible., Published as part of Ernst, Andrej & Carrera, Marcelo G., 2022, A cool-water bryozoan association from the La Pola Formation (Sandbian, Ordovician) of Argentine Precordillera, pp. 563-601 in Geodiversitas 44 (20) on pages 590-592, DOI: 10.5252/geodiversitas2022v44a20, http://zenodo.org/record/6725916, {"references":["MOROZOVA I. P. & LAVRENTJEVA V. D. 1981. - On the origin of the suborder Fenestellida. Paleontologicheskiy Zhurnal 2: 55 - 63 [in Russian].","BASSLER R. S. 1952. - Taxonomic notes on genera of fossil and Recent Bryozoa. Journal of the Washington Academy of Sciences 42: 381 - 385. https: // www. jstor. org / stable / 24531385"]}

Nicholsonella spinigera n. sp. (Figs 12G, H; 13 A-F; Appendix 1) urn:lsid:zoobank.org:act: 29ECE5F7-47D8-4DF3-8375-4BFEF20F02DF HOLOTYPE. — CEGH-UNC 27528 b, c. PARATYPES. — CEGH-UNC 27507 a, b, CEGH-UNC 27512 a, b, CEGH-UNC 27522 a, b, CEGH-UNC 27530 e, CEGH-UNC 27533 d, CEGH-UNC 27538 a, c, CEGH-UNC 27539 g. 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. — Ramose colonies with distinct exozones; secondary overgrowths occurring; autozooecial apertures angular with rounded corners; basal diaphragms abundant both in endozone and exozone, straight, or inclined; mesozooecia few, containing densely spaced thick diaphragms; acanthostyles large, 4-8 surrounding each autozooecial aperture, originating in endozone, having wide hyaline cores and narrow laminated sheaths; exozonal autozooecial walls thickly laminated, merged, showing reversal U-shaped lamination, without cingulum; maculae lacking. ETYMOLOGY. — The species name refers to large and abundant acanthostyles of the new species (from Latin “ spiniger ” – spinose). DESCRIPTION Branched colony with secondary overgrowths, 3.5-11.0 mm in diameter, with 0.45-1.30 mm wide exozones. Secondary overgrowths 1.05-2.00 mm thick.Autozooecial apertures angular with rounded corners. Basal diaphragms abundant both in endozone and exozone, straight, or inclined. Mesozooecia few, containing densely spaced thick diaphragms. Acanthostyles large, abundant, 4-8 surrounding each autozooecial aperture, originating in endozone, having wide hyaline cores and narrow laminated sheaths, often indenting autozooecia and mesozooecia. Autozooecial walls granular, 0.005 -0.010 mm thick, irregularly undulating in endozones; thickly laminated, merged, showing reversal U-shaped lamination, without cingulum, 0.05-0.09 mm thick in exozones. Maculae not observed. COMPARISON Nicholsonella spinigera n. sp. is similar to N. irregularis Loeblich, 1942 from the Bromide Formation (Sandbian) of Oklahoma (United States), but differs from it in more abundant acanthostyles (4-8 acanthostyles per autozooecial aperture vs 5-6 in N. irregularis) and in more abundant autozooecial diaphragms. Nicholsonella spinigera n. sp. differs from N. pulchra Ulrich, 1893 from the Upper Ordovician of United States in less abundant mesozooecia., Published as part of Ernst, Andrej & Carrera, Marcelo G., 2022, A cool-water bryozoan association from the La Pola Formation (Sandbian, Ordovician) of Argentine Precordillera, pp. 563-601 in Geodiversitas 44 (20) on pages 582-586, DOI: 10.5252/geodiversitas2022v44a20, http://zenodo.org/record/6725916, {"references":["LOEBLICH A. 1942. - Bryozoa from the Ordovician Bromide Formation, Oklahoma. Journal of Paleontology 16: 413 - 436. https: // www. jstor. org / stable / 1298838","ROSS J. R. P. 1963 a. - Chazyan (Ordovician) leptotrypellid and atactotoechid Bryozoa. Palaeontology 5: 727 - 739.","ULRICH E. O. 1893. - On Lower Silurian Bryozoa of Minnesota. The Geological and Natural History Survey of Minnesota, final report 3: 96 - 332. https: // doi. org / 10.5962 / bhl. title. 56338"]}

Genus Xenotrypa Bassler, 1952 TYPE SPECIES. — Fistulipora primaeva Bassler, 1911 by subsequent designation (Bassler 1952). Lower Ordovician (?Arenig); Russia. DIAGNOSIS. — Massive or encrusting colonies. Autozooecia slightly indented by acanthostyles. Diaphragms in autozooecia few to absent. Vesicles irregular, isolating autozooecia. Acanthostyles large, generally in autozooecial walls, some in vesicle walls; centres light to dark in colour. Autozooecial walls indistinctly laminated. OCCURRENCE. — Lower to Middle Ordovician of Russia and Argentina. COMPARISON Xenotrypa Bassler, 1952 differs from Hennigopora Bassler, 1952 in acanthostyles which do not significantly indent into the autozooecia, whereas acanthostyles in Hennigopora strongly indent autozooecia. Furthermore, vesicles usually completely isolate autozooecia in Xenotrypa, whereas the autozooecia in Hennigopora often share a common wall., Published as part of Ernst, Andrej & Carrera, Marcelo G., 2022, A cool-water bryozoan association from the La Pola Formation (Sandbian, Ordovician) of Argentine Precordillera, pp. 563-601 in Geodiversitas 44 (20) on page 568, DOI: 10.5252/geodiversitas2022v44a20, http://zenodo.org/record/6725916, {"references":["BASSLER R. S. 1952. - Taxonomic notes on genera of fossil and Recent Bryozoa. Journal of the Washington Academy of Sciences 42: 381 - 385. https: // www. jstor. org / stable / 24531385","BASSLER R. S. 1911. - The early Paleozoic Bryozoa of the Baltic Provinces. Bulletin of the Smithsonian Institution, United States National Museum 77: 1 - 382. https: // hdl. handle. net / 10088 / 30445"]}

Heterotrypa enodis n. sp. (Fig. 8 A-F; Appendix 1) urn:lsid:zoobank.org:act: C5482952-9218-4600-BDBE-C77CE258D9DD HOLOTYPE. — CEGH-UNC 27504 a-c (one colony, three thin sections). PARATYPES. — CEGH-UNC 27519 a, b (two thin sections of one colony), 27542 a, c-e (four thin sections of one colony). TYPE LOCALITY. — La Pola creek section near Albardon village, San Juan Province, Argentine Precordillera, western Argentina. TYPE HORIZON. — La Pola Formation, Upper Ordovician, Sandbian. ETYMOLOGY. — The species name refers to small acanthostyles of the new species (from Latin “ enodis ” – smooth). DIAGNOSIS. — Ramose colonies with distinct exozones; autozooecia with rounded-polygonal apertures; autozooecial diaphragms rare in endozone, common to abundant in exozone, developed as extension of wall cortex; mesozooecia moderately large, 1-4 surrounding each autozooecial aperture; acanthostyles small, 1-3 surrounding each autozooecial aperture; endozonal styles absent; autozooecial walls with distinct reverse V-shaped lamination with dark autozooecial border and weakly developed wall cortex continued in diaphragms; maculae consisting of macrozooecia. DESCRIPTION Ramose colonies, branch diameter 3.6 to 3.9 mm. Exozone distinct, 0.68 to 0.78 mm wide, endozone 2.24 to 2.34 mm wide. Autozooecia long, growing parallel to branch axis for a long distance in endozone, in exozone bending sharply and intersecting branch surface at angles of 66 to 74°, having rounded-polygonal shape in transverse section in endozone. Autozooecial apertures oval to polygonal. Autozooecial diaphragms thin, planar, widely spaced in endozone; common to abundant in exozone, planar, rarely inclined, developed as extension of wall cortex. Mesozooecia arising in endozone, polygonal in transverse section, few to common, 1-4 surrounding each autozooecial aperture. Mesozooecial diaphragms planar, densely spaced. Acanthostyles small, having laminated sheaths and indistinct hyaline cores, relatively abundant, 1-3 surrounding each autozooecial aperture. Endozonal styles absent. Autozooecial walls indistinctly laminated, 0.005 to 0.010 mm thick in endozone; displaying distinct reverse V-shaped structure with dark autozooecial border, with weakly developed wall cortex continued in diaphragms, 0.033 to 0.075 mm thick in exozone. Maculae consisting of macrozooecia, 1.25- 1.35 mm in diameter. COMPARISON The present species shows similarities to the genus Heterotrypa Nicholson, 1879 in the wall microstructure, abundant diaphragms arising from the wall cortex, presence of mesozooecia and acanthostyles. Heterotrypa enodis n. sp. differs from H. trentonensis (Ulrich, 1883) from the Upper Ordovician of North America in absence of endozonal styles, smaller exozonal acanthostyles (average acanthostyle diameter 0.03 mm vs 0.05 mm in H. trentonensis; measurements from Karklins 1984), and more abundant mesozooecia. Heterotrypa enodis differs from H. subtrentonensis Marintsch, 1998 from the Upper Ordovician of North America in absence of endozonal styles, less abundant exozonal acanthostyles (1-3 per aperture vs 3-5 in H. subtrentonensis), and more abundant mesozooecia., Published as part of Ernst, Andrej & Carrera, Marcelo G., 2022, A cool-water bryozoan association from the La Pola Formation (Sandbian, Ordovician) of Argentine Precordillera, pp. 563-601 in Geodiversitas 44 (20) on pages 574-576, DOI: 10.5252/geodiversitas2022v44a20, http://zenodo.org/record/6725916, {"references":["ULRICH E. O. 1886. - Descriptions of new Silurian and Devonian fossils. Bryozoa. Contributions to American Palaeontology 1: 8 - 33. https: // doi. org / 10.5962 / bhl. title. 140012","MCKINNEY F. K. 1971. - Trepostomatous Ectoprocta (Bryozoa) from the lower Chickamauga Group (Middle Ordovician), Wills Valley, Alabama. Bulletins of American Paleontology 60: 195 - 333. https: // www. biodiversitylibrary. org / page / 28721254","NICHOLSON H. A. 1879. - On the Structure and Affinities of the \" Tabulate Corals \" of the Paleozoic Period, with Critical Descriptions of Illustrative Species. 15 pls, 44 text-figs. William Blackwood and Sons, Edinburgh, 342 p. https: // doi. org / 10.5962 / bhl. title. 9117","ULRICH E. O. 1883. - American Palaeozoic Bryozoa. The Journal of the Cincinnati Society of Natural History 6: 245 - 279.","KARKLINS O. L. 1984. - Trepostome and cystoporate bryozoans from the Lexington Limestone and the Clays Ferry Formation (Middle and Upper Ordovician) of Kentucky, in POJETA J. Jr. (ed.), Contributions to the Ordovician paleontology of Kentucky and nearby states. United States Geological Survey, Professional Paper 1066 I: I 1 - I 102. https: // doi. org / 10.3133 / pp 1066 I","MARINTSCH E. J. 1998. - Systematic paleontology, biostratigraphy, and paleoecology of Middle Ordovician Bryozoa (Trepostomata) from the Hermitage Formation of East-Central Tennessee. Bulletins of American Paleontology 112: 1 - 121. https: // www. biodiversitylibrary. org / page / 10673542"]}

Chazydictya ornata n. sp. (Fig. 16 A-F; Appendix 1) urn:lsid:zoobank.org:act: 7D79E434-3513-4C96-8424-3A17DF9BB46A HOLOTYPE. — CEGH-UNC 27535 a. PARATYPES. — CEGH-UNC 27538 a, CEGH-UNC 27539 h. 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. — Bifoliate lenticular, branched colony; autozooecia short, arranged in 12-15 rows on branches; few basal diaphragms occurring; paurostyles abundant, large. ETYMOLOGY. — The species is named because of the ornamentation by abundant paurostyles (from Latin “ ornatus ” – adorned, decorated) DESCRIPTION Bifoliate lenticular, branched colony. Branches 1.4-2.0 mm wide and 0.6-1.0 mm thick. Mesotheca straight, 0.015 to 0.020 mm thick, without median rods. Autozooecia short, tubular, bending sharply to branch surface, rectangular to subrhomboidal at their bases, becoming oval at branch surface, arranged in 12 to 15 regular alternating rows on branches. Rare diaphragms occurring. Autozooecial walls granular, 0.01 to 0.02 mm thick in endozone; thick, finely laminated in exozone. Laminated skeleton well developed. Paurostyles abundant, 0.015 -0.035 mm in diameter. COMPARISON Chazydictya ornata n. sp. differs from C. chazyensis Ross, 1963 in presence of 12-15 rows of autozooecia on branches vs 8-12 in C.chazyensis,and in smaller autozooecial apertures(aperture width 0.06-0.08 mm vs 0.09-0.10 mm in C. chazyensis). Furthermore, Chazydictya ornata n. sp. has fewer diaphragms in autozooecia (none to one vs two-three in C. chazyensis) as well as larger paurostyles (0.015 -0.035 mm vs 0.010 mm in C. chazyensis).

Genus Heterotrypa Nicholson, 1879 TYPE SPECIES. — Monticulipora frondosa d’Orbigny, 1850 by subsequent designation (Utgaard & Boardman 1965). Cincinnatian, Upper Ordovician; North America. DIAGNOSIS. — Colonies frondose, ramose or less commonly encrusting. Autozooecial walls can be extremely variable in thickness. Zooecial boundary is a conspicuous dark line in inner exozones and in a broad zone of abutting laminae or completely obscured in outer exozones. Walls generally are amalgamate in appearance. Diaphragms are generally few in endozones, but are moderately abundant in some species. In exozones, diaphragms are closely and regularly spaced, thin, planar and perpendicular to the zooecial walls. Intermonticular mesozooecia range from abundant and regularly arranged to scattered or absent. Mesozooecia develop commonly moniliform chambers at proximal ends and tend to become smaller or are terminated distally within exozones. Diaphragms in mesozooecia noticeably thicker and more closely spaced than zooecial diaphragms. Acanthostyles are at least two kinds within the genus, regular acanthostyles limited to exozone, and the endacanthostyles originating in both endozone and exozone. Endacanthostyles occur in all species. Monticules generally have a central cluster of a few mesozooecia than those in the intermonticular area. OCCURRENCE. — Middle Ordovician-?Devonian; worldwide. COMPARISON The genus Heterotrypa Nicholson, 1879 differs from the genus Leioclema Ulrich, 1882 by abundant diaphragms in autozooecia, more angular apertural shape and two kinds of acanthostyles., Published as part of Ernst, Andrej & Carrera, Marcelo G., 2022, A cool-water bryozoan association from the La Pola Formation (Sandbian, Ordovician) of Argentine Precordillera, pp. 563-601 in Geodiversitas 44 (20) on page 574, DOI: 10.5252/geodiversitas2022v44a20, http://zenodo.org/record/6725916, {"references":["NICHOLSON H. A. 1879. - On the Structure and Affinities of the \" Tabulate Corals \" of the Paleozoic Period, with Critical Descriptions of Illustrative Species. 15 pls, 44 text-figs. William Blackwood and Sons, Edinburgh, 342 p. https: // doi. org / 10.5962 / bhl. title. 9117","UTGAARD J. & BOARDMAN R. S. 1965. - Heterotrypa Nicholson, 1879, and Peronopora Nicholson, 1881 (Bryozoa, Trepostomata): proposed designation of a type species in conformity with generally accepted usage. Bulletin of Zoological Nomenclature 22: 112 - 118. https: // www. biodiversitylibrary. org / page / 12223512","ULRICH E. O. 1882. - American Palaeozoic Bryozoa. The Journal of the Cincinnati Society of Natural History 5: 121 - 175, 233 - 257."]}

Trigonodictya elegans (Ulrich, 1893) (Fig. 14 D-H; Appendix 1) Pachidictya elegans Ulrich, 1893: 154, pl. 8, figs 18-19, pl. 9, figs 8-9. — Bassler 1911: 138, figs 62a-c. — Toots 1952: 130, pl. 8, fig. 4. ? Pachidictya elegans – Kiepura 1962: 408, pl. 7, fig. 3. Astreptodictya elegans – Karklins 1969: 57-58, pl. 11, figs 1-4. Trigonodictya elegans – Gorjunova & Lavretjeva 1993: 51. MATERIAL EXAMINED. — CEGH-UNC 27507 b, c, CEGH-UNC 27527 b, c, CEGH-UNC 27528 a-c, CEGH-UNC 27529 b, CEGH-UNC 27530 c, e, CEGH-UNC 27539 e, CEGH-UNC 27541 a, CEGH-UNC 27542 b, CEGH-UNC 27544 b. OCCURRENCE. — Upper Ordovician of United States and Europe. La Pola Formation, Upper Ordovician, Sandbian; La Pola creek section near Albardon village, San Juan Province, Argentine Precordillera, western Argentina. DESCRIPTION Branched bifoliate, dichotomous colonies. Branches flattened, with sharp edges, 2.40-3.25 mm wide and 0.9- 1.4 mm thick. Mesotheca three-layered, straight both in longitudinal and transverse sections, containing abundant median rods, 0.03-0.05 mm thick. Median rods densely spaced, 0.015 -0.038 mm in diameter, continuous in dark zones separating longitudinal rows of autozooecia. Autozooecia regularly arranged in 10-14 alternating longitudinal rows, semicircular to trapezoid in transverse section in endozone, rectangular in deep tangential section, becoming oval on the colony surface. Autozooecial diaphragms common, straight. Autozooecial walls laminated, 0.015 - 0.025 mm thick in endozones. Autozooecial boundaries distinct, delineated laterally by continuous dark zones. Extrazooecial skeletal deposits well developed, consisting of laminar and vesicular portions. Laminar stereom with dark zones, longitudinally aligned, separating autozooecia in exozones, containing abundant mural styles. Mural styles 0.02-0.04 mm in diameter. Vesicular structures small and sparse, having flat to rounded roofs, rare to common on branch edges. COMPARISON Trigonodictya elegans (Ulrich, 1893) is similar to T. cirrita Karklins, 1983 from the Upper Ordovician of United States and from the Las Plantas and Las Aguaditas formations (Sandbian) of Argentina, but differs from it in smaller autozooecial apertures (average aperture width 0.11 mm vs 0.14 mm in T. cirrita), and in larger distances between aperture centres (at average 0.36 mm vs 0.42 mm in T. cirrita). Trigonodictya elegans is similar to T. acuta (Hall, 1847) from the Middle Ordovician of New York, United States, but differs from it in smaller autozooecial apertures (aperture width 0.08-0.15 mm vs 0.10-0.16 mm in T. acuta)., Published as part of Ernst, Andrej & Carrera, Marcelo G., 2022, A cool-water bryozoan association from the La Pola Formation (Sandbian, Ordovician) of Argentine Precordillera, pp. 563-601 in Geodiversitas 44 (20) on page 588, DOI: 10.5252/geodiversitas2022v44a20, http://zenodo.org/record/6725916, {"references":["ULRICH E. O. 1893. - On Lower Silurian Bryozoa of Minnesota. The Geological and Natural History Survey of Minnesota, final report 3: 96 - 332. https: // doi. org / 10.5962 / bhl. title. 56338","BASSLER R. S. 1911. - The early Paleozoic Bryozoa of the Baltic Provinces. Bulletin of the Smithsonian Institution, United States National Museum 77: 1 - 382. https: // hdl. handle. net / 10088 / 30445","TOOTS H. 1952. - Bryozoen des estnischen Kuckersits. Mitteilungen aus dem Geologischen Staatsinstitut in Hamburg 21: 113 - 135.","KIEPURA M. 1962. - Bryozoa from the Ordovician erratic boulders of Poland. Acta Palaeontologica Polonica 7: 347 - 428.","KARKLINS O. L. 1969. - The cryptostome Bryozoa from the Middle Ordovician Decorah Shale, Minnesota. Minnesota Geological Survey Special Publication 6: 1 - 121. https: // hdl. handle. net / 11299 / 59956","KARKLINS O. L. 1983 a. - Ptilodictyoid cryptostomate Bryozoa from the Middle and Upper Ordovician rocks of Central Kentucky. Memoirs of the Paleontological Society 14: 1 - 31. https: // www. jstor. org / stable / 1315533","HALL J. 1847. - Graptolites of the Inferior strata of the New York system. Palaeontology of New York. Volume 1. Van Benthuysen, Albany, New York, 338 p. https: // doi. org / 10.5962 / bhl. title. 66970"]}

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., Published as part of Ernst, Andrej & Carrera, Marcelo G., 2022, A cool-water bryozoan association from the La Pola Formation (Sandbian, Ordovician) of Argentine Precordillera, pp. 563-601 in Geodiversitas 44 (20) on page 580, DOI: 10.5252/geodiversitas2022v44a20, http://zenodo.org/record/6725916, {"references":["ROSS J. R. P. 1963 a. - Chazyan (Ordovician) leptotrypellid and atactotoechid Bryozoa. Palaeontology 5: 727 - 739."]}

Genus Homotrypa Ulrich, 1882 TYPE SPECIES. — Homotrypa curvata Ulrich, 1882 by original designation. Cincinnatian, Upper Ordovician; North America. DIAGNOSIS. — Ramose and frondose colonies, often flattened, sometimes encrusting and irregularly massive in initial stages. Autozooecia with polygonal, rounded or oval apertures. Walls slightly thickened in exozone, integrate, diagonally and longitudinally laminated. Cystiphragms only in exozone, diaphragms commonly in exozone. Mesozooecia from rare to abundant, sometimes clustering in maculae. Acanthostyles abundant, commonly small. OCCURRENCE. — Middle Ordovician to Lower Silurian; North America, Europe, Australia, Siberia. COMPARISON The genus Homotrypa Ulrich, 1882 differs from the genus Monticulipora d’Orbigny, 1850 by its branched erect colony instead of the encrusting or massive one in Monticulipora. Furthermore, cystiphragms in Homotrypa are usually concentrated in the inner exozone, whereas cystiphragms in Monticulipora occur throughout autozooecial chambers., Published as part of Ernst, Andrej & Carrera, Marcelo G., 2022, A cool-water bryozoan association from the La Pola Formation (Sandbian, Ordovician) of Argentine Precordillera, pp. 563-601 in Geodiversitas 44 (20) on page 572, DOI: 10.5252/geodiversitas2022v44a20, http://zenodo.org/record/6725916, {"references":["ULRICH E. O. 1882. - American Palaeozoic Bryozoa. The Journal of the Cincinnati Society of Natural History 5: 121 - 175, 233 - 257."]}

Genus Chazydictya Ross, 1963 TYPE SPECIES. — Chazydictya chazyensis Ross, 1963 by original designation. Darriwilian, Ordovician; New York, United States. DIAGNOSIS. — Bifoliate lenticular, branched colonies. Branch transverse section lens-shaped. Autozooecia short, tubular, recumbent at their bases in endozone, bending sharply to colony surface, rectangular to subrhomboidal at their bases, becoming oval at branch surface, arranged in 8 to 15 regular alternating rows on branches. Hemisepta absent. Basal diaphragms rare to common. Mesotheca straight to weakly undulating, two-layered, without median rods. Autozooecial walls granular, in endozone; thick, finely laminated in exozone. Paurostyles in the laminated skeleton abundant, arranged in up to 5 rows between autozooecial apertures, rounded to weakly stellate in tangential section. Maculae absent. OCCURRENCE. — Darriwilian, Ordovician; United States, Canada. Sandbian, Ordovician; Argentina. COMPARISON Chazydictya Ross, 1963 differs from Ptilodictya Lonsdale, 1839 in absence of hemisepta and presence of abundant paurostyles., Published as part of Ernst, Andrej & Carrera, Marcelo G., 2022, A cool-water bryozoan association from the La Pola Formation (Sandbian, Ordovician) of Argentine Precordillera, pp. 563-601 in Geodiversitas 44 (20) on page 590, DOI: 10.5252/geodiversitas2022v44a20, http://zenodo.org/record/6725916, {"references":["ROSS J. R. P. 1963 a. - Chazyan (Ordovician) leptotrypellid and atactotoechid Bryozoa. Palaeontology 5: 727 - 739.","LONSDALE W. 1839. - Corals, in MURCHISON R. I. (ed.), The Silurian System. Part 2. Organic remains. John Murray, London: 675 - 694."]}

Arthroclema sp. A (Fig. 14 A-C; Appendix 1) MATERIAL EXAMINED. — CEGH-UNC 27525 a, CEGH-UNC 27528 b, CEGH-UNC 27529 b, CEGH-UNC 27530 e, f, CEGH-UNC 27533 c, CEGH-UNC 27538 c, CEGH-UNC 27539 a, e, f. OCCURRENCE. — La Pola Formation, Upper Ordovician, Sandbian; La Pola creek section near Albardon village, San Juan Province, Argentine Precordillera, western Argentina. DESCRIPTION Ramose colonies with well defined median axis, articulated and consisting of cylindrical segments. Segments apparently flexibly connected, 0.47-1.03 mm in diameter, with 0.10- 0.26 mm wide exozones and 0.27-0.54 mm wide endozones. Autozooecia moderate in size, budding from the median axis at angles of 45-56°, bending gently to branch surface, triangular in cross-section in endozone, becoming oval in exozone. Diaphragms in autozooecia few to absent. Autozooecial apertures narrow, oval, arranged regularly in alternating rows on branch surface. Walls in endozone hyaline, 0.01-0.02 mm thick, continuing in exozone into the peristomes. Fine longitudinal striation between apertures present. Extrazooecial skeleton finely laminated, having well defined zooecial boundaries. Paurostyles abundant, irregularly arranged between autozooecial apertures, arising in the outermost exozone. COMPARISON Arthroclema sp. A is similar to Arthroclema striatum Ulrich, 1890 from the Middle Ordovician of United States, and to A. pulchellum Billings, 1865 the Middle Ordovician of Canada. It differs from the latter in larger autozooecial apertures (0.07- 0.10 mm vs 0.06-0.07 mm in A. pulchellum; aperture width for A. pulchellum measured from Blake [1983: fig. 272g])., Published as part of Ernst, Andrej & Carrera, Marcelo G., 2022, A cool-water bryozoan association from the La Pola Formation (Sandbian, Ordovician) of Argentine Precordillera, pp. 563-601 in Geodiversitas 44 (20) on page 586, DOI: 10.5252/geodiversitas2022v44a20, http://zenodo.org/record/6725916, {"references":["ULRICH E. O. 1890. - Palaeozoic Bryozoa: III. Report of the Geological Survey of Illinois 8: 283 - 688.","BILLINGS E. 1865. - Paleozoic Fossils. Vol. 1. Containing Descriptions and Figures of New or Little Known Species of Organic Remains from the Silurian Rocks, 1861 - 1865. Geological Survey of Canada, Ottawa, 426 p.","BLAKE D. B. 1983. - Introduction to the Suborder Rhabdomesina. Systematic descriptions for the Suborder Rhabdomesina, in ROBI- SON R. A. (ed.), Treatise on Invertebrate Paleontology. Pt. G (1). Bryozoa (revised). Geological Society of America and University of Kansas Press, Lawrence: G 530 - G 592."]}

Genus Jordanopora Ross, 1963 TYPE SPECIES. — Jordanopora heroensis Ross, 1963 by original designation. Ordovician, Llanvirn-Llandeilo; United States. DIAGNOSIS. — Colonies ramose or encrusting, with distinct exozones. Autozooecia prismatic, autozooecial apertures rounded-polygonal. Diaphragms generally lacking in endozones; thin, planar, closely to widely spaced or lacking in exozones. Autozooecial walls thin, laminated, irregularly undulating in endozones; thickly laminated, without cingulum, broadly and irregularly serrated in exozones. Tubules in exozonal walls abundant, thick, hyaline, generally oriented parallel to autozooecial growth. Mesozooecia rare to common, originating in endozone, containing thick diaphragms. Styles absent. Maculae low to flush, consisting of macrozooecia surround cluster of mesozooecia and massive extrazooidal skeleton near centres. OCCURRENCE. — Chazy Series (Darriwilian-Sandbian) of New York, United States, and Sandbian of Argentina. COMPARISON Jordanopora Ross, 1963 differs from other genera of the Family Trematoporidae in absence of acanthostyles and presence of tubules in zooecial walls., Published as part of Ernst, Andrej & Carrera, Marcelo G., 2022, A cool-water bryozoan association from the La Pola Formation (Sandbian, Ordovician) of Argentine Precordillera, pp. 563-601 in Geodiversitas 44 (20) on page 580, DOI: 10.5252/geodiversitas2022v44a20, http://zenodo.org/record/6725916, {"references":["ROSS J. R. P. 1963 a. - Chazyan (Ordovician) leptotrypellid and atactotoechid Bryozoa. Palaeontology 5: 727 - 739."]}

Genus Arthroclema Billings, 1865 TYPE SPECIES. — Arthroclema pulchellum Billings, 1865 by original designation. Middle Ordovician, Trenton Limestone; Ottawa, Ontario, Canada. DIAGNOSIS. — Colonies branched, with well defined axial stem and alternate secondary and tertiary branches. Sinuous or straight longitudinal ridges separating apertural rows often present. Axial region formed by well defined linear axis. Autozooecia attenuated to weakly inflated at their bases, having subtriangular cross-section in endozone, becoming elliptical in exozone, orientated at angles of 30-90° to colony surface. Diaphragms rare to absent. Exozonal wall material well developed, with narrow zooecial boundaries. Metazooecia absent.Paurostyles scattered to common, usually developed on ridges. OCCURRENCE. — Middle to Upper Ordovician; North America, Europe. COMPARISON Arthroclema Billings, 1865 is similar to Helopora Hall in Silliman, Silliman & Dana, 1851, but differs from it in lacking metazooecia with diaphragms and acanthostyles. Arthroclema differs from Ulrichostylus Bassler, 1952 in wall structure with distinct zooecial boundaries., Published as part of Ernst, Andrej & Carrera, Marcelo G., 2022, A cool-water bryozoan association from the La Pola Formation (Sandbian, Ordovician) of Argentine Precordillera, pp. 563-601 in Geodiversitas 44 (20) on page 586, DOI: 10.5252/geodiversitas2022v44a20, http://zenodo.org/record/6725916, {"references":["BILLINGS E. 1865. - Paleozoic Fossils. Vol. 1. Containing Descriptions and Figures of New or Little Known Species of Organic Remains from the Silurian Rocks, 1861 - 1865. Geological Survey of Canada, Ottawa, 426 p.","SILLIMAN B., SILLIMAN B. JR & DANA J. D. 1851. - New genera of fossil corals from the report of James Hall, on the palaeontology of New York. American Journal of Sciences and Arts 2: 398 - 401.","BASSLER R. S. 1952. - Taxonomic notes on genera of fossil and Recent Bryozoa. Journal of the Washington Academy of Sciences 42: 381 - 385. https: // www. jstor. org / stable / 24531385"]}

Entre los temas de divulgación científica relacionados con la naturaleza o con acontecimientos biológicos, las catástrofes suelen atraer la mayor atención, entre ellas las extinciones masivas del tipo de la que eliminó a los dinosau- rios. No es tan frecuente que se recalquen sucesos más promisorios para el devenir de la vida, por ejemplo, la grandes radiaciones o diversificaciones. No obstante, extinciones y radiaciones han marcado la vida en el planeta y están ín- timamente relacionadas entre sí, ya que luego de las pri- meras sobrevienen las segundas y abren caminos para que se generan cambios profundos en la biota. La edad de la Tierra se suele estimar en unos 4600 mi- llones de años (Ma). En ese marco temporal, se calcula que los primeros registros de seres vivos, en forma de rastros de bacterias, datan de hace aproximadamente 3500Ma. El progreso de la vida en sus tiempos iniciales fue sumamen- te lento, pues solo a partir de hace unos 541Ma, cuando comenzó el Cámbrico, el primer período de la era paleo- zoica, se produjo un importante incremento de su ritmo de avance. Nos referimos a la radiación o explosión cámbrica –también tratada en el artículo ‘Los trilobites y el Paleo- zoico temprano’ en la página 17 de este número–, que causó la mayor diversificación de la que se tiene noticias y dio lugar a la aparición de los grandes tipos o phyla de animales. Luego de ese episodio ocurrió otra radiación, de menor escala, considerada por algunos una continuación de la anterior, que abarcó los taxones de menor rango de cada phylum. Se la conoce como la gran radiación ordovícica y acaeció a lo largo de casi todo el período geológico de ese nombre (485-444Ma), el segundo del Paleozoico. Fil: Carrera, Marcelo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; Argentina Fil: Balseiro, Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; Argentina