The aulaceratid stromatoporoids first appeared in the late Middle Ordovician and had achieved a worldwide distribution in tropical to subtropical shallow-marine environments by the Late Ordovician; however, their presence in Baltica has not been documented. Here, we report Aulacera vohilaidia Jeon and Toom sp. nov. from the Upper Ordovician Adila Formation (Pirgu Regional Stage; late Katian stage) of Estonia, which is the first record of an aulaceratid stromatoporoid in the Ordovician of Baltica. Aulacera vohilaidia Jeon and Toom sp. nov. is characterised by three distinct skeletal zones (axial, lateral, and outer), each of which consists of cyst plates with distinctive size and convexity. The axial zone is narrow, featuring large horseshoe-shaped cyst plates with a wavy, imbricated pattern in a line. The lateral zone consists of small cyst plates punctuated by sporadically developed pillars, and the outer zone comprises flat, parallel cyst plates. Ridged structures with cusps are formed by parallel cyst plates in the outer zone, and the growth surface displays a pustular reticulated structure with a polygonal morphology. The occurrence of Aulaceravohilaidia Jeon and Toom sp. nov. in Estonia extends the palaeogeographic distribution of aulaceratid stromatoporoids from peri-Gondwana, Laurentia, and Siberia to Baltica. The arrival of aulaceratid stromatoporoids in Baltica coincided with warming of the climate on the palaeocontinent and the expansion of the range of this group during the Late Ordovician.
Billings, E. 1857. Ordovician and Silurian Rocks of North America. Report of Progress for the Years 1853–1856. Geological Survey of Canada, Toronto.
Bogoyavlenskaya, O. V., Vassiljuk, N. P. and Glebov, A. R. 1990. Characteristics of several paleozoic Labechiida (Stromatoporata). In ископаемыепроблематики СССР (Fossil Problematica of the USSR) (Sokolov, B. S. and Zhuravleva, I. Т., eds). Труды института геологии и геофизики, 783. Nauka, Moscow, 76–87.
Bolton, T. E. 1988. Stromatoporoidea from the Ordovician rocks of central and eastern Canada. Geological Survey of Canada Bulletin, 379, 17–45.
https://doi.org/10.4095/126972
Cameron, D. and Copper, P. 1994. Paleoecology of giant Late Ordovician cylindrical sponges from Anticosti, E Canada. In Sponges in Time and Space (van Soest, R. W. N., van Kempen, T. M. G. and Braekmann, J. C., eds). Balkema Press, Amsterdam, 13–21.
Copper, P., Stock, C. W. and Jin, J. 2013. Quasiaulacera, a new Hirnantian (Late Ordovician) aulaceratid stromatoporoid genus from Anticosti Island, Canada. Journal of Paleontology, 87(4), 664–676.
https://doi.org/10.1666/12-150
Delabroye, A., Vecoli, M., Hints, O. and Servais, T. 2011. Acritarchs from the Ordovician–Silurian boundary beds of the Valga-10 drill core, southern Estonia (Baltica) and their stratigraphical and palaeobiogeographical implications. Palynology, 35(1), 4–45.
https://doi.org/10.1080/01916122.2010.491639
Dong, D. Y. 1982. Lower Ordovician stromatoporoids of Northern Anhui. Acta Palaeontologica Sinica, 21, 577–583.
Dong, D. Y. and Yang, J. Z. 1978. Lower Silurian stromatoporoids from northeastern Guizhou. Acta Palaeontologica Sinica, 17, 421–436.
Dronov, A. V., Kushlina, V. B. and Harper, D. A. T. 2016. A stromatoporoid trace fossil from the Upper Ordovician of the Siberian platform. In Ichnia 2016: Abstract Book (Baucon, A., Neto De Carvalho, C. and Rodrigues, J., eds). UNESCO Geopark Naturtejo / International Ichnological Association, Castelo Branco, 166–167.
Eisenack, A. 1934. Über Bohrlöcher in Geröllen baltischer Obersilurgeschiebe. Zeitschrift für Geschiebeforschung, 10, 89–94.
Foerste, A. F. 1909. Preliminary notes on Cincinnatian and Lexington fossils. Bulletin of the Scientific Laboratories of Denison University, 14, 289–324.
Galloway, J. J. 1957. Structure and classification of the Stromatoporoidea. Bulletins of American Paleontology, 37, 345–480.
Galloway, J. J. and St. Jean, J. 1961. Ordovician Stromatoporoidea of North America. Bulletins of American Paleontology, 43, 5–119.
Hints, L. and Meidla, T. 1997. Pirgu Stage. In Geology and Mineral Resources of Estonia (Raukas, A. and Teedumäe, A., eds). Estonian Academy Publishers, Tallinn, 82–85.
Hints, O. and Toom, U. 2023. ISOS-14 Field Guide: The Ordovician of Estonia. TalTech Department of Geology, Tallinn.
Hints, L., Oraspõld, A. and Nõlvak, J. 2004. Pirgu Stage in the East Baltic: lithotypes, biozonation and problems of correlation. In WOGOGOB-2004 Conference Materials. Abstracts and Field Guidebook (Hints, O. and Ainsaar, L., eds). University of Tartu Press, Tartu, 41–42.
Hints, L., Oraspõld, A. and Nõlvak, J. 2005. The Pirgu Regional Stage (Upper Ordovician) in the East Baltic: lithostratigraphy, biozonation and correlation. Proceedings of the Estonian Academy of Sciences, Geology, 54(4), 225–259.
https://doi.org/10.3176/geol.2005.4.02
Hints, L., Harper, D. A. T. and Paškevičius, J. 2018. Diversity and biostratigraphic utility of Ordovician brachiopods in the East Baltic. Estonian Journal of Earth Sciences, 67(3), 176–191.
https://doi.org/10.3176/earth.2018.14
Jeon, J., Li, Q., Chen, Z., Liang, K., Kershaw, S. and Zhang, Y. 2022a. Labechiid stromatoporoids from the Middle Ordovician Machiakou Formation of North China and their implications for the early development of stromatoporoids. Alcheringa: An Australasian Journal of Palaeontology, 46(3–4), 219–236.
https://doi.org/10.1080/03115518.2022.2130978
Jeon, J., Liang, K., Park, J., Kershaw, S. and Zhang, Y. 2022b. Diverse labechiid stromatoporoids from the Upper Ordovician Xiazhen Formation of South China and their paleobiogeographic implications. Journal of Paleontology, 96(3), 513–538.
https://doi.org/10.1017/jpa.2021.105
Jeon, J., Kershaw, S., Liang, K. and Zhang, Y. 2023. Stromatoporoids of the Katian (Upper Ordovician) Beiguoshan Formation, North China. Journal of Systematic Palaeontology, 21(1), 2234929.
https://doi.org/10.1080/14772019.2023.2234929
Kaljo, D., Klaamann, E. and Nestor, H. 1970. Paleobiogeographical review of Ordovician and Silurian corals and stromatoporoids. In Distribution and Sequence of Palaeozoic Corals of the USSR. Papers of II Allunion Symposium on fossil corals of the USSR, Vol. 3. Nauka, Moscow, 6–15.
Kaljo, D., Hints, L., Hints, O., Männik, P., Martma, T. and Nõlvak, J. 2011. Katian prelude to the Hirnantian (Late Ordovician) mass extinction: a Baltic perspective. Geological Journal, 46(5), 464–477
https://doi.org/10.1002/gj.1301
Knaust, D., Dronov, A. V. and Toom, U. 2023. Two almost‐forgotten Trypanites ichnospecies names for the most common Palaeozoic macroboring. Papers in Palaeontology, 9(3).
https://doi.org/10.1002/spp2.1491
Kröger, B., Hints, L. and Lehnert, O. 2017. Ordovician reef and mound evolution: the Baltoscandian picture. Geological Magazine, 154(4), 683–706.
https://doi.org/10.1017/S0016756816000303
Kühn, O. 1927. Zur Systematik und Nomenclatur der Stromatoporen. Zentralblatt Mineralogie, Geologie und Paläontologie B, 12, 546–551.
Nestor, H. 1964. Строматопороидеи ордовика и лландовери Эстонии (Ordovician and Llandoverian Stromatoporoidea of Estonia). Valgus, Tallinn.
Nestor, H. 1976. Раннепалеозойские строматопороидеи бассейна реки Мойеро (Север Сибирской платформы) (Early Paleozoic stromatoporoids from the Moiero River Basin (North of the Siberian Platform)), Valgus, Tallinn.
Nestor, H. 1999. Community structure and succession of Baltoscandian Early Palaeozoic stromatoporoids. Proceedings of the Estonian Academy of Sciences, Geology, 48(3), 123–139.
https://doi.org/10.3176/geol.1999.3.01
Nestor, H. and Einasto, R. 1997. Ordovician and Silurian carbonate sedimentation basin. In Geology and Mineral Resources of Estonia (Raukas, A. and Teedumäe, A., eds). Estonian Academy Publishers, Tallinn, 192–204.
Nestor, H. and Webby, B. D. 2013. Biogeography of the Ordovician and Silurian Stromatoporoidea. In Early Palaeozoic Biogeography and Palaeogeography (Harper, D. A. T. and Servais, T., eds). Geological Society of London, London, 67–79.
https://doi.org/10.1144/M38.7
Nestor, H., Copper, P. and Stock, C. 2010. Late Ordovician and Early Silurian Stromatoporoid Sponges from Anticosti Island, Eastern Canada: Crossing the O/S Mass Extinction Boundary. Canadian Science Publishing, Ottawa.
https://doi.org/10.1139/9780660199306
Nicholson, H. A. and Murie, J. 1878. The minute structure of the skeleton of Stromatopora and its allies. Zoological Journal of the Linnaean Society, 14, 187–246.
https://doi.org/10.1111/j.1096-3642.1878.tb01833.x
Ozaki, K. 1938. On some stromatoporoids from the Ordovician limestone of Shantung and south Manchuria. Journal of the Shanghai Science Institute, 2(2), 205–223.
Plummer, J. T. 1843. Suburban geology, or rocks, soil and water, about Richmond, Wayne County, Indiana. American Journal of Science, 44(2), 293–294.
Raymond, P. E. 1931. Further notes on Beatricea-like organisms. Bulletin Museum of Comparative Zoology, Geological Series, 9, 177–184.
Sokolov, B. S. 1951. Табуляты палеозоя Европейской части СССР, II, Силур Прибалтики: Фавозитиды лландоверского яруса (Tabulates from the Palaeozoic of the European part of the USSR, II, Ordovician of the West Urals and East Baltic area: Favositids from Llandovery). Trudy VNIGRI, 53, Gostoptekhizdat, Leningrad, Moscow.
Stock, C. W., Nestor, H. and Webby, B. D. 2015. Paleobiogeography of the Paleozoic Stromatoporoidea. In Treatise on Invertebrate Paleontology, Part E (Revised): Porifera, Vol. 4–5 (Selden, P. A., ed.). The University of Kansas Paleontological Institute, Lawrence, Kansas, 653–689.
Toom, U., Kuva, J. and Knaust, D. 2023. Ichnogenus Trypanites in the Ordovician of Estonia (Baltica). Estonian Journal of Earth Sciences, 72(1), 106–109.
https://doi.org/10.3176/earth.2023.48
Torsvik, T. H. and Cocks, L. R. M. 2017. Earth History and Palaeogeography. Cambridge University Press, Cambridge.
https://doi.org/10.1017/9781316225523
Truuver, K., Meidla, T. and Tinn, O. 2021. End-Ordovician ostracod faunal dynamics in the Baltic Palaeobasin. Estonian Journal of Earth Sciences, 70(1), 51–69.
https://doi.org/10.3176/earth.2021.02
Webby, B. D. 1971. Alleynodictyon, a new Ordovician stromatoporoid from New South Wales. Palaeontology, 14, 10–15.
Webby, B. D. 1991. Ordovician stromatoporoids from Tasmania. Alcheringa, 15(3), 191–227.
https://doi.org/10.1080/03115519108619018
Webby, B. D. 2004. Stromatoporoids. In The Great Ordovician Biodiversification Event (Webby, B. D., Paris, F., Droser, M. L. and Percival, I. G., eds). Columbia University Press, New York, 112–118.
https://doi.org/10.7312/webb12678-014
Webby, B. D. 2015a. Labechiida: systematic descriptions. In Treatise on Invertebrate Paleontology, Part E (Revised): Porifera, Vol. 4–5 (Selden, P. A., ed.). The University of Kansas Paleontological Institute, Lawrence, Kansas, 709–754.
Webby, B. D. 2015b. Early evolution of the Paleozoic Stromatoporoidea. In Treatise on Invertebrate Paleontology, Part E (Revised): Porifera, Vol. 4–5 (Selden, P. A., ed.). The University of Kansas Paleontological Institute, Lawrence, Kansas, 575–592
Webby, B. D. and Kershaw, S. 2015. External morphology of the Paleozoic Stromatoporoidea: shapes and growth habits. In Treatise on Invertebrate Paleontology, Part E (Revised): Porifera, Vol. 4–5 (Selden, P. A., ed.). The University of Kansas Paleontological Institute, Lawrence, Kansas, 419–486.
Webby, B. D., Stearn, C. W. and Nestor, H. 2015. Biostratigraphy of the Paleozoic Stromatoporoidea. In Treatise on Invertebrate Paleontology, Part E (Revised): Porifera, Vol. 4–5 (Selden, P. A., ed.). The University of Kansas Paleontological Institute, Lawrence, Kansas, 613–630.
Yabe, H. and Sugiyama, T. 1930. On some Ordovician stromatoporoids from South Manchuria, North China and Chosen (Korea), with notes on two new European forms. Science Reports of the Tohoku Imperial University, 2nd series, Geology, 14, 47–62.
Yavorsky, V. I. 1955. Stromatoporoidea Советского Союза, I (Stromatoporoidea of the Soviet Union, I). Trudy VSEGEI, Gosudarstvennoe nauchno-tehnicheskoe izdatel’stvo literatury po geologii i ohrane nedr, Moscow.
Yavorsky, V. I. 1957. Stromatoporoidea Советского Союза, II (Stromatoporoidea of the Soviet Union, II). Trudy VSEGEI, Gosudarstvennoe nauchno-tehnicheskoe izdatel’stvo literatury po geologii i ohrane nedr, Moscow.
Yavorsky, V. I. 1963. Stromatoporoidea Советского Союзa, IV (Stromatoporoidea of the Soviet Union, IV). Trudy VSEGEI, Gosudarstvennoe nauchno-tehnicheskoe izdatel’stvo literatury po geologii i ohrane nedr, Moscow.
