In living organisms, color patterns, behavior, and ecology are closely linked. Thus, detection of fossil pigments may permit inferences about important aspects of ancient animal ecology and evolution. Melanin-bearing melanosomes were suggested to preserve as organic residues in exceptionally preserved fossils, retaining distinct morphology that is associated with aspects of original color patterns. Nevertheless, these oblong and spherical structures have also been identified as fossilized bacteria. To date, chemical studies have not directly considered the effects of diagenesis on melanin preservation, and how this may influence its identification. Here we use time-of-flight secondary ion mass spectrometry to identify and chemically characterize melanin in a diverse sample of previously unstudied extant and fossil taxa, including fossils with notably different diagenetic histories and geologic ages. We document signatures consistent with melanin preservation in fossils ranging from feathers, to mammals, to amphibians. Using principal component analyses, we characterize putative mixtures of eumelanin and phaeomelanin in both fossil and extant samples. Surprisingly, both extant and fossil amphibians generally exhibit melanosomes with a mixed eumelanin/phaeomelanin composition rather than pure eumelanin, as assumed previously. We argue that experimental maturation of modern melanin samples replicates diagenetic chemical alteration of melanin observed in fossils. This refutes the hypothesis that such fossil microbodies could be bacteria, and demonstrates that melanin is widely responsible for the organic soft tissue outlines in vertebrates found at exceptional fossil localities, thus allowing for the reconstruction of certain aspects of original pigment patterns.

Chitin is present in fossil insects from the Oligocene (24.7 million years ago) lacustrine shales of Enspel, Germany. This result, which was obtained by analytical pyrolysis, extends by nearly 25 million years the length of time that chemically detectable remains of this biomolecule are known to survive. The embedding sediment is dominated by diatoms, which reflect high productivity in the paleolake. The primary control on the preservation of chitin is thus not time; it may persist in older sediments where suitable paleoenvironmental conditions prevailed.

Amphisbaenia is a speciose clade of fossorial lizards characterized by a snake-like body and a strongly reinforced skull adapted for head-first burrowing. The evolutionary origins of amphisbaenians are controversial, with molecular data uniting them with lacertids, a clade of Old World terrestrial lizards, whereas morphology supports a grouping with snakes and other limbless squamates. Reports of fossil stem amphisbaenians have been falsified, and no fossils have previously tested these competing phylogenetic hypotheses or shed light on ancestral amphisbaenian ecology. Here we report the discovery of a new lacertid-like lizard from the Eocene Messel locality of Germany that provides the first morphological evidence for lacertid-amphisbaenian monophyly on the basis of a reinforced, akinetic skull roof and braincase, supporting the view that body elongation and limblessness in amphisbaenians and snakes evolved independently. Morphometric analysis of body shape and ecology in squamates indicates that the postcranial anatomy of the new taxon is most consistent with opportunistically burrowing habits, which in combination with cranial reinforcement indicates that head-first burrowing evolved before body elongation and may have been a crucial first step in the evolution of amphisbaenian fossoriality.

Post-processing by means of a cation-exchanger-based protocol is an efficient strategy for purification and concentration of generator-derived 68 Ga. It ensures the removal of 68 Ge before 68 Ga-radiopharmaceutical preparation and high labeling yields of 68 Ga-labeled radiopharmaceuticals for routine medical application. Methods: In an effort to overcome the problem associated with acetone in the currently applied method, we have investigated the feasibility of replacing it with ethanol. The purification of 68 Ga from coeluted metallic impurities ( 68 Ge 41 , Fe 31 , Zn 21 , and Ti 41 ) on various cation-exchange columns has been investigated with a variety of post-processing solutions. As a proof of principle, the post-processed 68 Ga was used to radiolabel DOTATOC in combination with high-purity water and various buffer solutions. Results: An effective protocol for the processing of generator-produced 68 Ga on the basis of cation-exchange chromatography using EtOH/HCl medium has been developed. Up to 95% of the initially eluted 68 Ga activity can be collected in a 1-mL fraction of 90% EtOH/0.9N HCl after removal of 68 Ge-breakthrough in a washing step. The post-processed eluate has been used to radiolabel DOTATOC in yields of approximately 97% ± 0.25% at 80°C in 5 min. Conclusion: The described novel protocol improves the radiolabeling efficiency and efficacy of DOTATOC, providing yields of greater than 99% (decay-corrected). As a result, further purification to separate the desired product from uncomplexed 68 Ga is not necessary. The developed post-processing and labeling protocols permit reliable and high-yield preparation of injectable 68 Ga-DOTATOC (or other 68 Ga-labeled radiopharmaceuticals) that are suitable for routine application. It is possible to incorporate this protocol into existing automated modules.

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