On account of the lack of mineralised cuticles and their mainly terrestrial habitats, scorpions are scarce in the palaeontological record. Although listed since the Palaeozoic, only a few cases are known from the Triassic, Jurassic and Cretaceous periods. Sissom [19] reports five known occurrences during the Triassic and two in the Jurassic. Only recently have some discoveries confirmed the presence of scorpion fossils for the Cretaceous period [1], [13], [14] and [15]. The Fossil-Lagerstätten of the Upper Buntsandstein of northeastern France, the ‘Grès à Voltzia’ Formation, fortunately fill a gap in the record of the palaeontological history of scorpions. Particularly favourable circumstances have preserved non-mineralised soft tissues such as the chitin of arthropod cuticles from both terrestrial and aquatic faunas [4]. The Grauvogel and Gall collection is the result of tens of years prospecting in the ‘Grès à Voltzia’ localities. It contains several hundreds scorpion specimens, including some entire individuals. In account of their Anisian age, these fossils are older than those described by Wills [23] and [24] from the Triassic of Great Britain. Accurate diagnoses are proposed for the new families, genera and species described in this paper.

The ‘Grès à Voltzia’ correlates with the upper part of the Buntsandstein. It covers the passage of time between the fluviatile Lower Triassic red beds and the transgressive marine sedimentation of the Middle Triassic [5]. Its lower unit, or ‘Grès à meules’, is about 20 m thick and exhibits the typical facies interfingering of the subaerial part of a deltaic environment. The fossiliferous horizons are located in lenses of green or red shales that were deposited in temporary pools of water formed in abandoned channels or in depressions of the flood plain. The fossils are excellently preserved. They belong to aquatic animals (medusids, annelids, lingulids, bivalves, limulids, crustaceans, insect larvae, fishes) as well as to terrestrial animals (spiders, scorpions, myriapods, insects, reptile footprints) and to an abundant flora (ferns, horsetails, conifers). The vegetation grew on the margins of the channels and in standing bodies of water [6] that were also inhabited by numerous terrestrial arthropods. The scorpions lived in company with a varied entomological fauna comprising more than 200 species of insects (cockroaches, mayflies, beetles, bugs... [16]). The climate was semi-arid. During long dry seasons, the pools became isolated and dried out. From time to time, torrential rains generated floods that suddenly dropped the coarser sandy material downstream.

Since the major revision of Kjellesvig-Waering [10], summarized by Sissom [19], only a few additions to the known Palaeozoic fossils have been made, mainly by Jeram [7], [8] and [9]. Like Selden [17], this author adopted a scheme that followed the classification of Stockwell – unpublished PhD dissertation [20]. This treats scorpions as a class Scorpionida, with three orders: Protoscorpiones, Palaeoscorpiones, and Scorpiones. In their catalogue of the scorpions of the world, Fet et al. [3] insist on the complicate task of dealing with the analysis and classification of scorpions at the class/order group levels, since the Code does not regulate names above the rank of family. They retain the system of Kjellesvig-Waering [10] – with the family-group synonymies introduced later – as the only existing comprehensive system, but realize that future reanalysis will almost certainly result in significant changes.

Superfamily Buthoidea C.L. Koch, 1837 (sensu Lourenço)

Protobuthidae new family

With the exception of some Cretaceous fossils [1], [13], [14] and [15], previously described Mesozoic scorpion fossils from Jurassic and Triassic have not been assigned to any extant superfamily [19]. Careful analysis of several characters, and in particular of the trichobothrial pattern presented by this fossil element, led us to conclude that the new material described here can actually be placed in the superfamily Buthoidea sensu Lourenço [12]. This fossil family Protobuthidae shows some affinities with the Cretaceous fossil family Archaeobuthidae Lourenço, 2001 and with modern family Buthidae C.L. Koch, 1837. Several characters are, however, divergent, and the fossil scorpions appear to be more like a proto-element (sedis mutabilis) of these two families.

Diagnosis. Scorpions of medium to small size (32.5 mm in total length). Very slender body and appendages; pedipalps 18.9 and 19.2 mm in length. Median ocular tubercle only slightly anterior to the centre of the carapace; median eyes large and separated by less than one ocular diameter (see paratype). Metasomal segments: I with 10 carinae; II–IV with 8 carinae; V with 5 carinae. Telson: vesicle with an oval shape; aculeus slender and longer than the vesicle (see Table 1); subaculear tooth absent. Trichobothrial pattern very incomplete but recalling the ‘basic’ type A [21]. The following trichobothria can be observed: 3–4 dorso-external on chela manus; 2–3 in the fixed finger; 3–4 dorsal on patella; 2 dorsal and 1–2 external on the femur. Dentate margins of fixed finger probably composed of a single linear row of granules. Legs: tibial spurs not observable.

Type of the new family: genus Protobuthus new genus.

Type species: Protobuthus elegans sp. n.

Diagnosis: the same as for the new family.

Protobuthus elegans sp. n. (Fig. 1–3 and Fig. 10–24).

Type material. Holotype: 7899 (A–B); possibly an adult or pre-adult male, in part and counterpart. Paratype: 7907 (A-B); juvenile individual in part and counterpart. From France, Vosges, Voltzia Sandstone Formation, Bust (collection Grauvogel & Gall). Depositary: ‘Laboratoire de paléontologie, université Louis-Pasteur’, Strasbourg , France.

Etymology. The specific name makes reference to the slender body and appendages of this species.

Morphology. •

Prosoma: Anterior margin weakly emarginated, almost straight. No furrows can be observed clearly. Tegument rather smooth. Median ocular tubercle only slightly anterior to the centre of the carapace (see paratype); median eyes separated by less than one ocular diameter. Three or four pairs of lateral eyes can be observed with difficulty.

Superfamily Mesophonoidea Wills, 1910

Gallioscorpionidae new family

This fossil family is placed in the superfamily Mesophonoidea Wills. This decision is based mainly on the morphology of the carapace which has the median ocular tubercle placed at the anterior edge, on a prominent anterior median process. Further evidence will, however, be necessary to clarify the taxonomic position of all the elements placed in this superfamily.

Careful analysis of several characters led us to conclude that the new family described here shows some affinities with modern families, in particular the Buthidae, mainly on the basis of the position of some of the trichobothria.

Diagnosis. Scorpions of medium size (50 to 60 mm in total length). Slender body and moderately slender appendages. Carapace always wider than long; entire median ocular tubercle on the anterior edge of the carapace, situated in a protrusion or prominent anterior median process; eyes large and separated by less than one ocular diameter. Lateral eyes, apparently on an elevated protruding zone and composed of several oceles, but not compound. Sternum with a pentagonal shape, about three times longer than wide. Spiracles very small and slit-like to oval in shape. Pectines large with 31 to 38 teeth; fulcra present. Trichobothrial pattern very incomplete but recalling the ‘basic’ type A [20]. The following trichobothria can be observed: 2 dorso-external on chela manus; 2 on the fixed finger; 3 dorsal and 1 internal on patella; 2 dorsal, 1 external and 1 internal on the femur. Dentate margins of fixed finger probably composed of a single linear row of granules. Legs: pedal spurs present on legs III–IV. Tibial spurs present on leg IV, strong.

Type of the new family: genus Gallioscorpio new genus.

Type species: Gallioscorpio voltzi sp. n.

Diagnosis: the same as for the new family.

Gallioscorpio voltzi sp. n. (Figs. 3–9, 13–24).

Type material. Holotype; 7890 (A), France, Vosges, Voltzia Sandstone Formation, Bust (Collection Grauvogel & Gall), sex unknown in part only. Paratypes composed of a few almost complete specimens and several hundred fragments, all from France, Vosges, Voltzia Sandstone Formation. Depositary: ‘Laboratoire de Paléontologie, université Louis-Pasteur’, Strasbourg, France.

Etymology. The specific name is dedicated to Philippe Louis Voltz, an outstanding Alsatian geologist from the 19th century.

Coloration. In some of the best-preserved specimens, a dark reddish to almost blackish coloration can be observed, but it is uncertain whether this is original or an artefact of fossilization.

Morphology. •

Prosoma: carapace always wider than long; entire median ocular tubercle on the anterior edge of the carapace, situated on a protrusion or prominent anterior median process; eyes large and separated by less than one ocular diameter. Lateral eyes, apparently on an elevated protruding zone and composed of several oceles, but not compound. Two furrows present just behind the prominent anterior median process; a central median furrow can be observed on the posterior region of the carapace. Tegument smooth. Sternum with a pentagonal shape, about three times longer than wide.

The earliest scorpions occur in the Silurian and are contemporaneous with terrestrialization, i.e. the transition of animals from the aquatic habitat to land. They lived in the water and respired through gills. Terrestrial scorpions appear in the Carboniferous. Their respiratory organs are book lungs, opening to the outside through stigma. Aquatic genera survived until Triassic. Today, all living scorpions are terrestrial and have nocturnal activity. The Grès à Voltzia specimens undoubtedly belong to animals that lived on land. Scorpions are predators hunting on smaller animals. In the Buntsandstein landscapes, they found a large range of prey, particularly insects, at their disposal. A certain eclecticism in the choice of prey may explain the coexistence of two species, a slender beside a stockier one, in the same biotopes. Possibly, some scorpions also ate myriapods [11].

The Grès à Voltzia faunas and floras are of Anisian age and belong to an interval of time corresponding with the first million of years of the Mesozoic [2]. They give evidence for the recovery of the biosphere that followed the dramatic end-Permian mass extinction. The Palaeozoic faunal reduction affected taxonomic groups differently. The Trilobites had definitely disappeared by the end of the Permian, but Early Triassic Crustacea contain genera inherited from the Palaeozoic (Euthycarcinus, Halicyne) that persist alongside taxa announcing the arrival of modern faunas (isopods, decapods). During the Triassic, the earliest known flies (Diptera) [16] and the oldest known mygalomorph spiders [18] appear in company of ‘living fossils’, i.e. taxa with very low rates of speciation, such as lingulids, coelacanths, scorpions, cockroaches (Blattodea) and the species Triops cancriformis, which is apparently very close to recent representatives. Such an evolutionary stasis cannot fail to intrigue. The Grès à Voltzia deltaic environment, a transitional area located between land and the aquatic realm, developed many fragmented habitats that constituted not only refuges for ancestral taxa but also cradles for the emergence of new groups.

The frequent occurrence of scorpions in the fossiliferous localities of the Buntsandstein confirms the outstanding position occupied by these arthropods among the small predators of the Triassic period. Considered as ‘living fossils’ or panchronological animals, the Grès à Voltzia taxa differ nevertheless both from the former Palaeozoic families and from the Mesophonidae of the Middle Triassic of Great Britain. Most remarkable is the fact that at least one family, Protobuthidae, can, to some extent, be classified together with the Cretaceous fossil family, Archaeobuthidae and the extant family Buthidae within the Superfamily Buthoidea. Modern Buthidae are therefore presumably associated with lineages at least 240 Myr old. This is considerably older than the 125-Myr age previously established for the Archaeobuthidae [13]. On the other hand, Gallioscorpio voltzi, which still exhibits features inherited from Palaeozoic scorpions, is related to a group of organisms that became extinct during the Triassic.

Once again, Buntsandstein appears to be a post-extinction recovery time of the biosphere when Palaeozoic survivors coexisted in particular habitats with more modern groups, before being finally supplanted by them.