New observations and interpretations of the enigmatic poorly know Late Paleozoic Irregularina Bykova, 1955

0392566 - GLÚ 2014 RO eng J - Journal Article
Schlagintweit, F. - Hladil, Jindřich - Nose, M.
New observations and interpretations of the enigmatic poorly know Late Paleozoic Irregularina Bykova, 1955.
Acta Palaeontologica Romaniae. Roč. 9, č. 1 (2013), s. 3-22. ISSN 1842-371X
Institutional support: RVO:67985831
Keywords : Parathuramminida * incertae sedis * psammobionts * cryptoendoliths * protozoa
Subject RIV: DB - Geology ; Mineralogy

Specimens of the enigmatic poorly known taxon Irregularina Bykova, usually classified as a parathuramminid foraminifer, occur in great abundances irregularly distributed within fine-grained wacke-/packstones, partly pressing against bioclasts. The aggregation of their numerous and variously shaped sparite-filled bodies within the sediment may resemble abiogenic fenestral fabrics. It is suggested that these organisms were sediment-dwelling (psammobiontic) forms being capable of stretching into sediment interstices. In Amphipora wackestones, Irregularina settles on amphiporids skeletons and cryptoendolithically penetrates the latter by completely mimicing the labyrinthic canal system. Given the wide range of intraspecific variation by adaptation of the dynamic shape, the high species diversity of Irregularina based on differences in morphology and size is challenged. The irregular shape with finger-like extensions interpreted as moveable pseudopodia (lobopodia) and the supposed ability to change the shape requires a primarily not calcified, flexible outer body membrane. Therefore Irregularina shares some similarities with modern giant amoeboid heterotrophic protists that may also exhibit a psammobiontic way of life. Another cross-reference is given to homeomorphic representatives of Mesozoic thaumatoporellaceans. The true biogenic nature of Irregularina, however, is still unsolved.
Permanent Link: http://hdl.handle.net/11104/0221392