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In the present paper we trace the patterns of convergent evolution of encrusting calcareous polychaetes and tentaculitoids with respect to the morphology and function of their tubes. Both clades have morphologically similar tubes. Six of the eight basic morphotypes of encrusting tubeworms occur both in calcareous polychaetes and in tentaculitoids. All six encrusting tentaculitoid tubeworm morphotypes distinguished have analogues among serpulid and sabellid polychaetes. Both tentaculitoids and polychaetes with calcareous tubes have a similar plesiomorphic morphotype, which is characterized by substrate parallel, irregular growth away from the initial point of encrustation. Dominance of similarities in the order of evolution of morphotypes in the calcareous tubeworms indicates that despite genetic differences, ecological similarities (suspension feeding) and similarities in the tube material (calcareous), as well as body plan (worm-like) had a strong control over the evolution of calcareous tubeworms. The calcareous tubeworm life modes likely appeared in the order of increasing dependence on the type of substrate. In general, possible antipredatory strategies (spines, keels, cryptic and endobiotic mode of life) of calcareous tubeworms are evolutionarily old. The plesiomorphic general hard substrate encrusters are evolutionarily the most successful and have the longest stratigraphic range both in tube-dwelling polychaetes and tentaculitoids. Innovations, such as attachment of the tube by basal projections were developed in some microconchid tentaculitoids but not in calcareous polychaetes; budding tubes occur in both taxa, however, in microconchid tentaculitoids it was a brief evolutionary event, whereas in polychaetes such pseudocolonies have a long stratigraphic range. The ability to live in brackish and fresh waters by some tentaculitoids and tube-dwelling polychaetes seems not to be associated with any particular tube morphotype.

Abstract: Depositional redox conditions of the uppermost Bajocian–Bathonian (Middle Jurassic) ore-bearing clays of the Gnaszyn/Kawodrza area in the Polish Jura have been determined using an integrated geochemical (Th/U and U/Th ratios, degree of pyritisation (DOP), sulphur stable isotopes, biomarker analysis) and petrographic approach (measurements of pyrite framboid diameters, and microfacies analysis). The Th/U and U/Th ratios indicate that oxic conditions prevailed on the sea-floor during this interval, and 34S isotopes suggest open-system conditions. DOP values, however, are rather scattered, and may reflect oxic, dysoxic, or anoxic conditions. We consider that the DOP values result from reducing conditions within the sediment and the chemistry of the pore-waters, rather than true sea-floor redox conditions. Pyrite framboid populations also indicate that dysoxic conditions prevailed within the sediment, beneath an oxygenated water column. Biomarker data did not provide any evidence of water column stratification or anoxia during sedimentation of the Middle Jurassic clays.

Abstract: Biomarkers are widely known to occur in the fossil record, but the unaltered biomolecules are rarely reported from sediments older than Paleogene. Polar terpenoids, the natural products most resistant to degradation processes, were reported mainly from the Tertiary conifers, and the oldest known are Cretaceous in age. In this paper, we report the occurrence of relatively high concentrations of ferruginol derivatives and other polar diterpenoids, as well as their diagenetic products, in a conifer wood Protopodocarpoxylon from the Middle Jurassic of Poland. Thus, the natural product terpenoids reported in this paper are definitely the oldest polar biomolecules detected in geological samples. The extracted phenolic abietanes like ferruginol and its derivatives (6,7-dehydroferruginol, sugiol, 11,14-dioxopisiferic acid) are produced only by distinct conifer families (Cupressaceae s. l., Podocarpaceae and Araucariaceae), to which Protopodocarpoxylon could belong based on anatomical characteristics. Therefore, the natural product terpenoids are of great advantage in systematics of fossil plant remains older than Paleogene and lacking suitable anatomical preservation.