Dasycladalean green algae and associated foraminifers in Middle Triassic (Lower and Middle Muschelkalk) carbonates of the south-eastern Germanic Basin (Upper Silesia, Poland)

Abstract

Middle Triassic dasycladalean algae occur in limestones and dolstones of the Diplopora Beds in Upper Silesia, a region representing the southern part of the Germanic Basin. The dasycladales assemblage of this area was studied by Kotanski at the end of the last century, mostly from dolomitized and weathered material. The relatively well-preserved specimens the authors found in thin sections from undolomitized strata allowed the description and revised taxonomical assignment of the algae. The identified microflora includes: Diplopora annulatissima Pia, 1920, Diplopora annulata (Schafhautl, 1853), alpingoporella cf. krupkaensis Kotanski, 2013, Physoporella prisca Pia, 1912, Physoporella cf. pauciforata (Gumbel, 1872), Holosporella ? sp. 1, and Holosporella ? sp. 2. Diplopora annulatissima and Favoporella annulata Sokac, 1986 are regarded here as two different species. Oligoporella elegans Assmann ex Pia, 1931, extensively illustrated and described by Kotanski (2013), is considered a junior synonym of Oligoporella prisca Pia, 1912, and transferred to the genus Physoporella emended by Grgasovic, 1995. Also, some of the dasycladalean algae ( Salpingoporella cf. krupkaensis , Holosporella ? sp. 1, and Holosporella ? sp. 2) described here could represent new species, but more well-preserved material is necessary. The algae are accompanied by foraminiferal microfauna, which collectively indicate a late Anisian (Illyrian) age of the strata studied.