Morphological stasis in the first myxomycete from the Mesozoic, and the likely role of cryptobiosis

Past and Ongoing Field-Based Studies of Myxomycetes

Evidence from molecular studies indicates that myxomycetes (also called myxogastrids or plasmodial slime molds) have a long evolutionary history, and the oldest known fossil is from the mid-Cretaceous. However, they were not "discovered" until 1654, when a brief description and a woodcut depicting what is almost certainly the common species Lycogala epidendrum was published. First thought to be fungi, myxomycetes were not universally recognized as completely distinct until well into the twentieth century. Biodiversity surveys for the group being carried out over several years are relatively recent, with what is apparently the first example being carried out in the 1930s. Beginning in the 1980s, a series of such surveys yielded large bodies of data on the occurrence and distribution of myxomycetes in terrestrial ecosystems. The most notable of these were the All Taxa Biodiversity Inventory (ATBI) project carried out in the Great Smoky Mountains National Park, the Planetary Biodiversity Inventory Project (PBI) carried out in localities throughout the world, and the Myxotropic project being carried out throughout the Neotropics. The datasets available from both past and ongoing surveys now allow global and biogeographical patterns of myxomycetes to be assessed for the first time.

The largest amber-preserved flower revisited

Amber exquisitely preserves the delicate organs of fossil flowers for millions of years. However, flower inclusions can be rare and usually do not exceed 10 mm in size. Here we report an exceptionally large flower from late Eocene Baltic amber, measuring 28 mm across, which is about three times as large as most floral inclusions. This fossil was described over 150 years ago as Stewartia kowalewskii (Theaceae) and has never been revised. The analysis of pollen extracted from the anthers of the flower inclusion, however, revealed strong affinities to Asian species of Symplocos (Symplocaceae), prompting the new combination Symplocos kowalewskii comb. nov. et emend. This fossil represents the first record of Symplocaceae from Baltic amber and supports affinities of its flora to evergreen broadleaved and mixed mesophytic forests of present-day East and Southeast Asia. The rarity of such large-sized flower inclusions is likely due to the size of the resin outpouring and its properties, which might affect the embedding of plant organs.

Successful extraction of insect DNA from recent copal inclusions: limits and perspectives

Insects entombed in copal, the sub-fossilized resin precursor of amber, represent a potential source of genetic data for extinct and extant, but endangered or elusive, species. Despite several studies demonstrated that it is not possible to recover endogenous DNA from insect inclusions, the preservation of biomolecules in fossilized resins samples is still under debate. In this study, we tested the possibility of obtaining endogenous ancient DNA (aDNA) molecules from insects preserved in copal, applying experimental protocols specifically designed for aDNA recovery. We were able to extract endogenous DNA molecules from one of the two samples analyzed, and to identify the taxonomic status of the specimen. Even if the sample was found well protected from external contaminants, the recovered DNA was low concentrated and extremely degraded, compared to the sample age. We conclude that it is possible to obtain genomic data from resin-entombed organisms, although we discourage aDNA analysis because of the destructive method of extraction protocols and the non-reproducibility of the results.