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Parachasmatopora undefined-a

Parachasmatopora undefined-a

GBIF:196202555

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Descriptions(5)

(Figs 16 G; 17 A-E)
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
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
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
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.
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
OCCURRENCE. — La Pola Formation, Upper Ordovician, Sandbian; La Pola creek section near Albardon village, San Juan Province, Argentine Precordillera, western Argentina.
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
MATERIAL EXAMINED. — CEGH-UNC 27526 a, CEGH-UNC 27529 b, CEGH-UNC 27533 a, CEGH-UNC 27545 a, b.
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

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CLASSIFICATION

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AnimaliaBryozoaStenolaemataFenestridaChasmatoporidaeParachasmatoporaParachasmatopora undefined-a

MULTIMEDIA

Media Files(2)

FIG. 16. — A-F, Chazydictya ornata n. sp., holotype CEGH-UNC 27535 a: A, B, branch transverse thin section showing autozooecial chambers and mesotheca without rods; C, branch transverse thin section showing autozooecial walls with paurostyles; D, E, tangential thin section showing autozooecial apertures and paurostyles; branch transverse thin section showing autozooecial mesotheca without rods; G, Parachasmatopora sp. A, tangential section showing reticulate colony, CEGH-UNC 27526 a. Scale bars: A, G, 0.5 mm; B, D, 0.2 mm; C, E, F, 0.1 mm.

Imageimage/png© Ernst, Andrej;Carrera, Marcelo G.Ernst, Andrej;Carrera, Marcelo G.

FIG. 17. — A-E, Parachasmatopora sp. A: A-C, tangential section showing branches with autozooecial apertures and chambers, CEGH-UNC 27526 a; D, branch transverse section showing autozooecial chambers and laminated skeleton, CEGH-UNC 27545 a; E, branch longitudinal section showing autozooecial chambers with diaphragms and laminated skeleton, CEGH-UNC 27545 b. Scale bars: A, D, E, 0.5 mm; B, C, 0.2 mm.

Imageimage/png© Ernst, Andrej;Carrera, Marcelo G.Ernst, Andrej;Carrera, Marcelo G.

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Source Information

A cool-water bryozoan association from the La Pola Formation (Sandbian, Ordovician) of Argentine Precordillera

checklist

This dataset contains the digitized treatments in Plazi based on the original journal article 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

ABSTRACT

Nineteen bryozoan species belonging to 18 genera are described from the La Pola Formation (Sandbian, Upper Ordovician) of Argentine Precordillera. Two trepostome genera each with one new species, respectively, are new: Albardonia bifoliata n. gen., n. sp. and Argentinopora robusta n. gen., n. sp. Five more species are new: a cystoporate Xenotrypa argentinensis n. sp., two trepostomes Heterotrypa enodis n. sp. and Nicholsonella spinigera n. sp., as well as two ptilodictyines Pseudostictoporella simplex n. sp. and Chazydictya ornata n. sp. The studied fauna shows some connection with Laurentia and Baltica on the species level and is similar to Siberia on the generic level. Furthermore, the generic composition of the La Pola fauna is similar to contemporary faunas of Las Aguaditas and Las Plantas formations of the Argentine Precordillera. The described fauna comes from mixed carbonate-siliciclastic deposits and represents a largely para-autochthonous association, with few autochthonous elements.The bryozoan growth forms indicate shallow shelf conditions. Bryozoans are associated with brachiopods, red algae, and echinoderms indicating heterozoan community typical for temperate to cool water environments with high primary production.

MOTS CLÉS

Ordovicien,

Sandbien,

environnement d’eau

froide,

Bryozoa,

paléogéographie,

paléoécologie,

genres nouveaux,

espèces nouvelles.

Ernst A, Carrera M G, admin (2022). A cool-water bryozoan association from the La Pola Formation (Sandbian, Ordovician) of Argentine Precordillera. Geodiversitas. Checklist dataset https://doi.org/10.15468/22hb3y accessed via GBIF.org on 2026-06-16.

CC0Published 6/16/2022View dataset
GBIF Usage Key
196202555
Dataset Key
f8f165f8-1b6b-4639-b139-c47e48485949
Origin
source
Taxon ID
865C87FDFFBFFFFF39FBFB414C2AF963.taxon
Last Crawled
6/9/2026
Last Interpreted
6/9/2026
View on GBIFSource Reference