Revision of the Ordovician acritarch genus Ampullula Righi 1991

After the initial description of Ampullula Righi 1991 and Stelomorpha Yin 1994, several researchers discussed these two acritarch genera and their relationship. A literature revision and investigation of new material from South China indicate that the genus Stelomorpha is a synonym of the genus Ampullula, but Ampullula is not the synonym of the genus Tranvikium Tynni 1982 emend. Uutela and Sarjeant 2000. The generic diagnosis of Ampullula is emended. Six species belong to the genus: Ampullula calix (Quintavalle and Playford, 2008) comb. nov., Ampullula composta (Yin et al., 1998) comb. nov., Ampullula crassula (Vavrdová, 1990) comb. et emend. nov., Ampullula erchunensis (Fang, 1986) Brocke 1997 emend. nov., Ampullula princeps Brocke 1997, and Ampullula suetica Righi 1991. Ampullula was widely distributed throughout peri-Gondwana and Baltica suggesting a global distribution during the late Early–Middle Ordovician. Biostratigraphically, Ampullula is an important genus indicating upper Lower to Middle Ordovician intervals. Ampullula was first present in the eobifidus graptolite Biozone in South China, where it possibly originated, and subsequently was also present on Baltica and other parts of the margin of Gondwana. Thus, Ampullula was an important Early–Middle Ordovician acritarch with a global distribution, which probably was both eurythermic and eurytopic.