Caradocian Chitinozoa from Dalarna, Sweden

Two sections through Caradocian strata in Dalarna, Central Sweden, have been investigated as to their content of acid-resistant microfossils. The vast amount of Chitinozoa (incertae sedis) found is treated in this study. Twenty-seven species belonging to the genera Acanthochitina, Conochitina, Cyathcchitina, Desmochitina, Eremochitina, Lagenochitina, Spinachitina, and Tanuchitina are described. Eight new species are proposed, viz., Conochitinia dolosa, C. hirsuta, C. suecica, C. tigrina, Desmochitina juglandiformis, D. piriformis, Eremochitina dalbyensis, and Tanuchitina bergstroemi. The fauna as a whole displays pronounced affinities with Estonian material described earlier by Eisenack and although several species have a wide stratigraphic range, some of them, e.g., Acanthochitina barbata, Cyathochitina stentor, Desmochitina lata, D. nodosa, Lagenochitina baltica, and L. prussica must be regarded as excellent aids in stratigraphy. Treatment of samples, chitinozoan frequency and state of preservation are discussed and a survey of stratigraphic and geographic distribution is included. On account of presence of details in ornamentation interpreted as having had buoyant effect, it is concluded that the group probably had a planktonic and, possibly, pseudoplanktonic mode of life.