External and internal morphological characters of extant and fossil organisms are crucial to establishing their systematic position, ecological role and evolutionary trends. The lack of internal characters and soft-tissue preservation in many arthropod fossils, however, impedes comprehensive phylogenetic analyses and species descriptions according to taxonomic standards for Recent organisms. We found well-preserved three-dimensional anatomy in mineralized arthropods from Paleogene fissure fillings and demonstrate the value of these fossils by utilizing digitally reconstructed anatomical structure of a hister beetle. The new anatomical data facilitate a refinement of the species diagnosis and allowed us to reject a previous hypothesis of close phylogenetic relationship to an extant congeneric species. Our findings suggest that mineralized fossils, even those of macroscopically poor preservation, constitute a rich but yet largely unexploited source of anatomical data for fossil arthropods.DOI: http://dx.doi.org/10.7554/eLife.12129.001

Fossil representatives of the hydrophilid genera Hydrochara Berthold, 1827, Hydrobiomorpha Blackburn, 1888 and Hydrophilus Geoffroy, 1762 were recorded at the lower Middle Eocene locality Grube Messel in Germany. Four morphospecies were recognised, including Hydrobiomorpha eopalpalis, sp. nov. showing sexually dimorphic maxillary palpomere 2 unknown in any recent or fossil species of the genus. These fossils are the oldest known records of the mentioned genera and indicate a minimum age of 47 million years for the divergence of the Hydrobiomorpha and Hydrophilus clades. Based on these data, we assume that the diversification of the ‘greater hydrophilines’ clade predated the lower Middle Eocene. The fossil record of the subtribe Hydrophilina is briefly reviewed, the reasons of the scarcity or absence of some genera in the fossil record are discussed, and the paleoenviromental significance of the presented fossils is discussed.

Fossil water scavenger beetles (Coleoptera: Hydrophilidae) of the latest Oligocene Rott Formation are revised, based on the examination of the type specimens, as well as numerous additional material from Statz (Los Angeles) and Kastenholz (Bonn) collections. Seven hydrophilid species are recognized, five of which are reliably attributed to the following genera: Berosus morticinus (von Heyden and von Heyden, 1866), Paracymus excitatus (von Heyden and von Heyden, 1866), Paracymus sp., Hydrobiomorpha fraterna (von Heyden, 1859), and Hydrophüus rottensis (Statz, 1939). Coccinella? protogaeae Germar 1837 is attributed to the subtribe Hydrophilina, and Cymbiodyta? austera Statz 1939 to the subfamily Hydrophilinae. Hydrous ebeninus Statz 1939 and Paracymus excitatus (form 3) are excluded from the Hydrophiloidea. Berosus capitatus Statz 1939 is synonymized with Berosus morticinus, and Hydrous neptunus von Heyden and von Heyden 1866 with Hydrobiomorpha fraterna. Lectotypes of Philydrus morticinus von Heyden and von Heyden 1866 and Hydrous ebeninus Statz 1939 are designated. The significance of the hydrophilid fossils for paleoecological reconstructions of the former Rott Lake is briefly discussed.

The Sandfish (Scincidae: Scincus Scincus) Is a Lizard Capable of Moving through Desert Sand in a Swimming-Like Fashion. the Epidermis of this Lizard Shows a High Resistance against Abrasion Together with a Low Friction to Sand as an Adaption to a Subterranean Life below the Desert’s Surface, Outperforming even Steel. the Low Friction Is Mainly Caused by Chemical Composition of the Scales, which Consist of Glycosylated β-Keratins. in this Study, the Friction, the Micro-Structure, the Glycosylation of the β-Keratin Proteins and β-Keratin Coding DNA of the Sandfish in Comparison to other Reptilian Species Was Investigated, Mainly with the Closely Related Berber Skink (Scincidae: Eumeces Schneideri) and another Sand Swimming Species, the Not Closer Related Shovel-Snouted Lizard (Lacertidae: Meroles Anchietae). Glycosylated β-Keratins of the Sandfish, Visualized with Different Lectins Resulted in O-Linked Glycans through PNA Employed as Carbohydrate Marker. Furthermore, the Glycosylation of β-Keratins in Various Squamatean Species Was Investigated and All Species Tested Were Found Positive; however, it Seems Like both Sand Swimming Species Examined Have a much Stronger Glycosylation of their β-Keratins. in Order to Prove this Finding through a Genetic Foundation, DNA of a β-Keratin Coding Gene of the Sandfish Was Sequenced and Compared with a Homologue Gene of Eumeces Schneideri. by Comparison of the Protein Sequence, a Higher Abundance of O-Glycosylation Sites Was Found in the Sandfish (enabled through the Amino Acids Serine and Threonine), Giving Molecular Support for a Higher Glycosylation of the β-Keratins in this Species.

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