Earliest styliolinids from the Wenlock of Saaremaa Island (Estonia): paleoecological and evolutionary implications

Tentaculitoids (class Tentaculita Bouček, 1964) are problematic tubicolous invertebrates that first appeared in the Ordovician and were most common in the Silurian and Devonian oceans (Lyashenko, 1955, Lyashenko, 1957, Wei et al., 2012, Wei, 2019). The free living tentaculitoids belong to two subclasses: Dacryoconarida Fisher, 1962 and Chonioconarida Farsan, 1994, all inhabited in normal marine environments. Most free-living tentaculitoids were benthic animals but the members of order Dacryoconarida were pelagic (Alberti, 2000). The encrusting tentaculitoids belong to orders Cornulitida Bouček, 1964 and Microconchida Weedon, 1991, the latter also colonized in fresh water environments (Zatoń et al., 2012, Zatoń and Peck, 2013, Shcherbakov et al., 2021).

The zoological affinities of tentaculitoids have long been debated. However, they exhibit the most similarities with lophophorates, such as brachiopods and bryozoans (Taylor et al., 2010, Vinn and Zatoń, 2012). In the past, they have often been affiliated with molluscs and annelids.

The free-living tentaculitoids of Baltica have generally received little attention with exception of a monograph by Larsson (1979) and a paper by Lyashenko (1958) which introduce several new taxa and provide systematic descriptions of the Baltic tentaculitoid fauna. However, pelagic tentaculilitids have never been described from the Silurian deposits of Baltica.

The aims of the paper are to: 1) describe earliest pelagic tentaculitoids from the Silurian of Estonia; 2) discuss paleoecology of pelagic tentaculitoid association; and 3) discuss evolution of pelagic tentaculitoids.

Please cite this article as: O. Vinn, A.A. Alkahtane, M.M. El Hedeny, S. Al Farraj, U. Toom, Earliest styliolinids from the Wenlock of Saaremaa Island (Estonia): paleoecological and evolutionary implications, Palaeoworld (2023), doi: https://doi.org/10.1016/j.palwor.2023.09.004