Scorpions trapped in amber: a remarkable window on their evolution over time from the Mesozoic period to present days

This synoptic review aims to bring some general information on fossil scorpions, namely those trapped in amber - fossilized resin - ranging from Lower Cretaceous through the Palaeocene and up to the Miocene. The question to be addressed is how the study of these fossils can be connected with possible present scorpionism problems. A precise knowledge of these ancient lineages provides information about the evolution of extant lineages, including the buthoids, which contain most known noxious species. Among the Arthropods found trapped in amber, scorpions are considered rare. A limited number of elements have been described from the Late Tertiary Dominican and Mexican amber, while the most ancient Tertiary amber from the Baltic region produced more consistent results in the last 30 years, primarily focusing on a single limited lineage. Contrarily, the Cretaceous amber from Myanmar, also called Burmite, has yielded and continues to yield a significant number of results represented by several distinct lineages, which attest to the considerable degree of diversity that existed in the Burmese amber-producing forests. As in my previous similar contributions to this journal, the content of this note is primarily addressed to non-specialists whose research embraces scorpions in various fields such as venom toxins and public health. An overview knowledge of at least some fossil lineages can eventually help to clarify why some extant elements associated with the buthoids represent dangerous species while others are not noxious.(AU)

Growth, delayed fluorescence and pigment composition of four Prorocentrum minimum strains growing at two salinities

Prorocentrum minimum is a potentially harmful and widely distributed marine dinoflagellate. Several P. minimum strains have already been studied, showing phylogenetical relations of strains isolated from the same geographical regions. Similarity among the strains was further examined on the basis of their physiology. Pigment composition and concentration, as well as delayed fluorescence (DF) decay kinetics and intensity, were measured in four P. minimum strains isolated from the Baltic and Adriatic Seas. The strains were grown at two salinities characteristic of the Baltic (8 PSU) and North Adriatic Seas (32 PSU). Strain differences in DF decay kinetics and growth did not always follow their genetic relations. While two strains showed similarities to the previously described strains from the Baltic and Adriatic Seas in DF parameters, the other two strains seemed to be specific. The differences among strains isolated from the same sea could stem from adaptations to conditions in the specific habitats. Cluster analysis based on the ratio of individual carotenoid pigments concentrations to the chlorophyll a concentration or to total carotenoids were not conclusive in showing relations among the strains. Among the measured pigments, only peridinin concentration depended on salinity in all st.