Laser-stimulated fluorescence reveals unseen details in fossils from the Upper Jurassic Solnhofen Limestones

Laser-stimulated fluorescence (LSF) has seen increased use in palaeontological investigations in recent years. The method uses the high flux of laser light of visible wavelengths to reveal details sometimes missed by traditional long-wave ultraviolet (UV) methods using a lamp. In this study, we compare the results of LSF with UV-A-generated fluorescence on a range of fossils from the Upper Jurassic Solnhofen Limestone Konservat-Lagerstätte of Bavaria, Germany. The methodology follows previous protocols of LSF with modifications made to enhance laser beam intensity, namely keeping the laser at a constant distance from the specimen, using a camera track. Our experiments show that along with making surface details more vivid than UV-A or revealing them for the first time, LSF has the additional value of revealing shallow subsurface specimen detail. Fossil decapods from the Solnhofen Limestone reveal full body outlines, even under the matrix, along with details of segmentation within the appendages such as limbs and antennae. The results indicate that LSF can be used on invertebrate fossils along with vertebrates and may often surpass the information provided by traditional UV methods.

Laser-stimulated fluorescence reveals unseen details in fossils from the Solnhofen Limestone (Upper Jurassic, Bavaria, Germany)

Laser-Stimulated Fluorescence (LSF) has seen increased use in palaeontological investigations in recent years. The method uses the high flux of laser light to reveal details sometimes missed by ultraviolet (UV) and optical wavelengths. In this study, we compare the results of LSF with UV on a range of fossils from the Upper Jurassic Solnhofen Limestone Konservat-Lagerstätte of Bavaria, Germany. The methodology follows previous protocols with modifications made to enhance laser beam intensity. Our experiments show the value of LSF in revealing shallow subsurface detail of specimens, previously not widely applied to Solnhofen fossils. In particular, fossil decapods from the Solnhofen Limestone reveal full body outlines, even under the matrix, along with details of segmentation within the appendages such as limbs and antennae. The results indicate that LSF can be used on both vertebrate and invertebrate fossils and may surpass the information provided by traditional UV methods in some specimens.

New fossil Odonata from the Upper Jurassic of Bavaria with a new fossil calibration point for Zygoptera

Three new taxa of odonates are described from the Upper Jurassic Solnhofen limestone from Eichstätt and Painten in Bavaria (Germany), including the first two genuine Zygoptera (Andrephlebia buergeri gen. et sp. nov. in fam. inc. sed. and Jurahemiphlebia haeckeli gen. et sp. nov. in Hemiphlebiidae) and a new taxon of Stenophlebioptera (Reschiostenophlebia koschnyi gen. et sp. nov. in Stenophlebiidae). With an age of about 152 million years, the holotype of Jurahemiphlebia from the Painten locality represents the oldest fossil record and thus a new calibration point for crown group Zygoptera, Lestoidea, and Hemiphlebiidae, and the oldest record for any living odonate family. Furthermore, the first relatively complete specimen of the dragonfly Prohemeroscopus kuehnapfeli (Prohemeroscopidae) is described, which was previously known only from a pair of isolated hind wings. A revised diagnosis is provided for the species and genus.

Solnhofener Plattenkalk: a heritage stone of international significance from Germany

In Bavaria (Germany), between Solnhofen and Kelheim, numerous quarries allow utilization of a thinly plated Upper Jurassic limestone known in German as the Solnhofener Plattenkalk and in English as Solnhofen Limestone. Here limestone slabs have been quarried for centuries and it is not necessary to cut the limestone with a saw as it can be split conveniently into thin and even slabs or sheets which are used for floor tiles and wall cladding. Thick slabs of especially fine quality have been used for lithography. This later utilization began in the late eighteenth century with lithographic Solnhofen Limestone soon being marketed worldwide. The industry continues on a smaller scale today. Slabs are quarried by hand so as not to break them, accounting for their high price. Because of this ‘gentle’ quarrying method, fossils have also been found. Although rare, over time many Solnhofen fossil specimens have found their way into natural history museums throughout the world. Most noteworthy is the early bird Archaeopteryx. Given its utilitarian usage worldwide as a lithographic stone, and its sale for centuries as floor tiles, coupled with its being a source of unique fossils, Solnhofener Plattenkalk is recommended here as a Global Heritage Stone Resource.

A cautionary tail: Cyrtura temnospondyla Jaekel, 1904, an enigmatic vertebrate specimen from the Late Jurassic Solnhofen Limestone

The enigmatic vertebrate taxon Cyrtura temnospondyla is reassessed following the location and reuniting of both counterparts. The specimen, comprising a series of caudal vertebrae from the Tithonian Solnhofen Limestone, has variously been interpreted as derived either from a temnospondyl amphibian, or a turtle, or to be indeterminate. The redescription of this caudal series reveals that the vertebrae have a single centrum, in contrast to previous descriptions. This specimen is here interpreted to be the tail of a turtle more derived than Proganochelys and Meiolania, but is otherwise indeterminate and cannot be associated with any of the diagnosed taxa from the Solnhofen Limestone. Cyrtura temnospondyla lacks any diagnostic character and must therefore be considered a nomen dubium.