The diversity of Silurian microconchids is still poorly understood. Here, a new microconchid tubeworm species, Palaeoconchus wilsoni, is described from the Silurian (Ludlow) encrusting rugose corals from Estonia (Saaremaa Island) and a brachiopod shell from Sweden (Gotland). In Estonia, the microconchids are a dominant constituent of the encrusting assemblages, associated with cornulitids, Anticalyptraea, auloporids, trepostome bryozoans, hederelloids and enigmatic ascodictyids. It is notable that these Silurian encrusting assemblages are clearly dominated by tentaculitoids (microconchids, cornulitids and Anticalyptraea) which very often co-exist on the same coral host. Morphologically similar microconchids and Anticalyptraea may have exploited a more similar ecological niche than the straight-shelled cornulitids. However, the clear predominance of microconchids over Anticalyptraea in the communities may indicate that this genus was a less effective competitor for food than microconchid tubeworms.
Baird, G. C. & Brett, C. E. 1983. Regional variation and paleontology of two coral beds in the Middle Devonian Hamilton Group of western New York. Journal of Paleontology, 57, 417–446.
Balon, K. 2015. Epibionts on the Middle Devonian Corals from the Laskowa Quarry, Holy Cross Mountains. Unpublished M. Sc. Thesis, University of Silesia, Faculty of Earth Sciences, 51 pp. [in Polish].
Bickert, T., Pätzold, J., Samtleben, C. & Munnecke, A. 1997. Paleoenvironmental changes in the Silurian indicated by stable isotopes in brachiopod shells from Gotland, Sweden. Geochimica et Cosmochimica Acta, 61, 2717–2730.
http://dx.doi.org/10.1016/S0016-7037(97)00136-1
Bouček, B. 1964. The Tentaculites of Bohemia. Publication of Czechoslovakian Academy of Sciences, Prague, 125 pp.
Fraiser, M. L. 2011. Paleoecology of secondary tierers from Western Pangean tropical marine environments during the aftermath of the end-Permian mass extinction. Palaeogeography, Palaeoclimatology, Palaeoecology, 308, 181–189.
http://dx.doi.org/10.1016/j.palaeo.2010.12.002
He, L., Wang, Y., Woods, A., Li, G., Yang, H. & Liao, W. 2012. Calcareous tubeworms as disaster forms after the end-Permian mass extinction in south China. PALAIOS, 27, 878–886.
http://dx.doi.org/10.2110/palo.2012.p12-022r
Hints, O., Ainsaar, L., Männik, P. & Meidla, T. (eds). 2008. The Seventh Baltic Stratigraphical Conference: Abstracts and Field Guide. Geological Society of Estonia, Tallinn, 158 pp.
Jürgenson, E. 1988. Deposition of the Silurian Beds in the Baltic. Valgus, Tallinn, 175 pp. [in Russian, with English summary].
Kaljo, D. (ed.). 1970. The Silurian of Estonia. Valgus, Tallinn, 343 pp. [in Russian, with English summary].
Larsson, K. 1979. Silurian tentaculitids from Gotland and Scania. Fossils and Strata, 11, 1–180.
Lescinsky, H. L., Edinger, E. & Risk, M. J. 2002. Mollusc shell encrustation and bioerosion rates in a modern epeiric sea: taphonomy of experiments in the Java Sea, Indonesia. PALAIOS, 17, 171–191.
http://dx.doi.org/10.1669/0883-1351(2002)017<0171:MSEABR>2.0.CO;2
Liddell, W. D. & Brett, C. E. 1982. Skeletal overgrowths among epizoans from the Silurian (Wenlockian) Waldron Shale. Paleobiology, 8, 67–78.
Mistiaen, B., Brice, D., Zapalski, M. K. & Loones, C. 2012. Brachiopods and their auloporid epibionts in the Devonian of Boullonais (France): comparison with other associations globally. In Earth and Life, International Year of Planet Earth (Talent, J. A., ed.), pp. 159–188. Springer.
Olempska, E. & Rakowicz, Ł. 2014. Affinities of Palaeozoic encrusting ascodictyid ‘pseudobryozoans’. Journal of Systematic Palaeontology, 12, 983–999.
http://dx.doi.org/10.1080/14772019.2013.850118
Pineda, J., Riebensahm, D. & Medeiros-Bergen, D. 2002. Semibalanus balanoides in winter and spring: larval concentration, settlement, and substrate occupancy. Marine Biology, 140, 789–800.
http://dx.doi.org/10.1007/s00227-001-0751-z
Sando, W. J. 1984. Significance of epibionts on horn corals from the Chainman Shale (Upper Mississippian) of Utah. Journal of Paleontology, 58, 185–196.
Taylor, P. D. & Vinn, O. 2006. Convergent morphology in small spiral worm tubes (‘Spirorbis’) and its palaeoenvironmental implications. Journal of the Geological Society, London, 163, 225–228.
http://dx.doi.org/10.1144/0016-764905-145
Vinn, O. 2006. Two new microconchid (Tentaculita Bouček 1964) genera from the Early Palaeozoic of Baltoscandia and England. Neues Jahrbuch für Geologie und Paläontologie, Monatshefte, 2006/2, 89–100.
Vinn, O. & Isakar, M. 2007. The tentaculitid affinities of Anticalyptraea from the Silurian of Baltoscandia. Palaeontology, 50, 1385–1390.
http://dx.doi.org/10.1111/j.1475-4983.2007.00715.x
Vinn, O. & Mutvei, H. 2005. Observations on the morphology and affinities of cornulitids from the Ordovician of Anticosti Island and the Silurian of Gotland. Journal of Paleontology, 79, 726–737.
http://dx.doi.org/10.1666/0022-3360(2005)079[0726:OOTMAA]2.0.CO;2
Vinn, O. & Wilson, M. A. 2012. Epi- and endobionts on the Late Silurian (Early Pridoli) stromatoporoids from Saaremaa Island, Estonia. Annales Societatis Geologorum Poloniae, 82, 195–200.
Weedon, M. J. 1991. Microstructure and affinity of the enigmatic Devonian tubular fossils Trypanopora. Lethaia, 24, 223–227.
http://dx.doi.org/10.1111/j.1502-3931.1991.tb01471.x
Wilson, M. A. & Taylor, P. D. 2006. Predatory drillholes and partial mortality in Devonian colonial metazoans. Geology, 34, 565–568.
http://dx.doi.org/10.1130/G22468.1
Wilson, M. A. & Taylor, P. D. 2014. The morphology and affinities of Allonema and Ascodictyon, two abundant Palaeozoic encrusters commonly misattributed to the ctenostome bryozoans. Studi Trentini di Scienze Naturali, 94, 259–266.
Yang, H., Chen, Z.-Q., Wang, Y., Ou, W., Liao, W. & Mei, X. 2015. Palaeoecology of microconchids from microbialites near the Permian–Triassic boundary in South China. Lethaia, 48, 497–508.
http://dx.doi.org/10.1111/let.12122
Zatoń, M. & Krawczyński, W. 2011a. Microconchid tubeworms across the upper Frasnian–lower Famennian interval in the Central Devonian Field, Russia. Palaeontology, 54, 1455–1473.
http://dx.doi.org/10.1111/j.1475-4983.2011.01110.x
Zatoń, M. & Krawczyński, W. 2011b. New Devonian microconchids (Tentaculita) from the Holy Cross Mountains, Poland. Journal of Paleontology, 85, 757–769.
http://dx.doi.org/10.1666/11-005.1
Zatoń, M. & Vinn, O. 2011. Microconchids and the rise of modern encrusting communities. Lethaia, 44, 5–7.
http://dx.doi.org/10.1111/j.1502-3931.2010.00258.x
Zatoń, M., Vinn, O. & Tomescu, A. M. F. 2012a. Invasion of freshwater and variable marginal marine habitats by microconchid tubeworms – an evolutionary perspective. Geobios, 45, 603–610.
http://dx.doi.org/10.1016/j.geobios.2011.12.003
Zatoń, M., Wilson, M. A. & Vinn, O. 2012b. Redescription and neotype designation of the Middle Devonian microconchid (Tentaculita) species ‘Spirorbis’ angulatus Hall, 1861. Journal of Paleontology, 86, 417–424.
http://dx.doi.org/10.1666/11-115.1
Zatoń, M., Taylor, P. D. & Vinn, O. 2013. Early Triassic (Spathian) post-extinction microconchids from western Pangea. Journal of Paleontology, 87, 159–165.
http://dx.doi.org/10.1666/12-060R.1
Zatoń, M., Zhuravlev, A. V., Rakociński, M., Filipiak, P., Borszcz, T., Krawczyński, W., Wilson, M. A. & Sokiran, E. 2014a. Microconchid-dominated cobbles from the Upper Devonian of Russia: opportunism and dominance in a restricted environment following the Frasnian–Famennian biotic crisis. Palaeogeography, Palaeoclimatology, Palaeoecology, 401, 142–153.
http://dx.doi.org/10.1016/j.palaeo.2014.02.029
Zatoń, M., Hagdorn, H. & Borszcz, T. 2014b. Microconchids of the species Microconchus valvatus (Münster in Goldfuss, 1831) from the Upper Muschelkalk (Middle Triassic) of Germany. Palaeobiodiversity & Palaeoenvironments, 94, 453–461.
http://dx.doi.org/10.1007/s12549-013-0128-6
http://dx.doi.org/10.1016/j.palaeo.2015.02.021