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Temporal range: Upper Ordovician - Middle Jurassic (Taylor and Vinn, 2006)
|Palaeoconchus angulatus (Hall, 1861) on a brachiopod from the Middle Devonian (Givetian) of Michigan|
The Order Microconchida is a group of small, spirally-coiled, encrusting fossil "worm" tubes found from the Upper Ordovician to the Middle Jurassic (Bathonian) around the world. They have lamellar calcitic shells, usually with pseudopunctae or punctae and a bulb-like origin. Many were long misidentified as the polychaete annelid Spirorbis until studies of shell microstructure and formation showed significant differences. All pre-Cretaceous "Spirorbis" fossils are now known to be microconchids. Their classification at the phylum level is still debated. Most likely they are some form of lophophorate, a group which includes phoronids, bryozoans and brachiopods. Microconchids are phylogenetically closely related to the other encrusting tentaculitoid tubeworms, such as Anticalyptraea, trypanoporids and cornulitids.
- Weedon, M.J. 1991. "Microstructure and affinity of the enigmatic Devonian tubular fossil Trypanopora". Lethaia 24:227-234.
- Vinn, O. 2006. "Two new microconchid (Tentaculita Bouček 1964) genera from the Early Palaeozoic of Baltoscandia and England". Neues Jahrbuch für Geologie und Paläontologie 2006:89-100.
- Vinn, O. 2010. "Adaptive strategies in the evolution of encrusting tentaculitoid tubeworms". Palaeogeography, Palaeoclimatology, Palaeoecology 292:211–221.
- Vinn, O. & Mutvei, H. 2009. "Calcareous tubeworms of the Phanerozoic". Estonian Journal of Earth Sciences 58:286-296.
- Zaton, M. & Vinn, O. 2011. "Microconchids and the rise of modern encrusting communities". Lethaia 44:5-7 doi:10.1111/j.1502-3931.2010.00258.x
- 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.
- Wilson, M.A., Yancey, T.E. and Vinn, O. 2011. "A new microconchid tubeworm from the Lower Permian (Artinskian) of central Texas, USA". Acta Palaeontologica Polonica 56:785-791 doi:10.4202/app.2010.0086.
- Zaton, M., Wilson, M.A. and Vinn, O. 2012. "Redescription and neotype designation of the Middle Devonian microconchid (Tentaculita) species ‘Spirorbis’ angulatus Hall, 1861". Journal of Paleontology 86:417-424.