Acrothyra is an extinct genus of gregarious brachiopod that lived during the Middle Cambrian. Fossils of this genera can be found in Canada in formations such as the Burgess Shale and the Forteau Formation.
There are currently 253 specimens of Acrothyra that are known from the Greater Phyllopod bed, where they comprise 0.5% of the community.
Taxonomy
Species This genus currently contains five described species. They are listed below:https://www.gbif.org/species/search?rank=SPECIES&highertaxon_key=4864454&status=ACCEPTED&status=DOUBTFUL
Acrothyra bonnia Skovsted, Knight, Balthasar & Boyce, 2017Skovsted, Christian & Knight, I & Balthasar, Uwe & Boyce, DW. (2017). Depth related brachiopod faunas from the lower Cambrian Forteau Formation of southern Labrador and western Newfoundland, Canada. Palaeontologia Electronica. 54A. 10.26879/775. Acrothyra gregaria Walcott, 1901 Acrothyra minor Walcott, 1905 Acrotreta proavia (Matthew, 1899) (Type species) Acrothyra sera Mathew, 1902 Landing, Ed & Johnson, Susan & Geyer, Gerd. (2008). Faunas and Cambrian Volcanism on the Avalonian Marginal Platform, Southern New Brunswick. Journal of Paleontology. 82. 884-905. 10.1666/07-007.1.
Description Members of this genus have short apsacline ventral pseudointerarea with a triangular intertrough. The interior of the ventral valve is elongated with its apical process reaching about one-third of its valve length. It also has a triangular depression without apical pits.
References
Notes BABCOCK, L. E., R. A. ROBISON, M. N. REES, S. PENG, AND M. R. SALTZMAN. 2007. The global boundary stratotype section and point (GSSP) of the Drumian Stage (Cambrian) in the Drum Mountains, Utah, USA. :, 30(002):85-95. MATTHEW, G. F. 1901. Acrothyra. A new genus of Etcheminian brachiopods. Nat. Hist. Soc. New Brunswick, Bull, 4:303-304. ROWELL, A. H. 1966. Revision of some Cambrian and Ordovician inarticulate brachiopods. YOCHELSON, E. L. 1961. The operculum and mode of life of Hyolithes. Journal of Paleontology:152-161.
External links "Acrothyra gregaria" . Burgess Shale Fossil Gallery. Virtual Museum of Canada. 2011. (Burgess Shale species 17)