In the last 15 years, the discovery of several new actinopterygian fish faunas from the Early and Middle Triassic of the Tethys, cast new light on the timing, speed and range of their recovery after the end-Permian crisis. In addition to several new taxa having been described, the stratigraphical and geographical record of many others have been greatly extended. In fact, most of the new fossiliferous sites are in southern China, thus at the Eastern end of the Tethys, and furthermore a few are somewhat older (Chaohu, Panxian, Luoping) than the major classical Western Tethys sites (Monte San Giorgio). Following these new finds, it is possible to have a better definition of the Triassic recovery stages. Indeed, after a quite short phase till the end of the Smithian (Olenekian, Early Triassic) in which a rather consistent fauna was present all around the Pangea coasts, a major radiation occurred in the Early-Middle Anisian after the new Middle Triassic fish fauna already appeared in the late Early Triassic, thus occuring well before what was previously supposed from the Alps localities. Furthermore, the new assemblages from southern China point to an early broader differentiation among the basal neopterygians rather than in the 'subholosteans', the group that was then dominant in the Western Tethys since the Late Anisian. It stands that during the Norian a new basal neopterygian radiation gave rise to several new branches that dominated the remaining part of the Mesozoic.

Materials with radiopacity lower than enamel might be misinterpreted as secondary enamel caries on radiographic images, especially when applied as initial increment on the proximal gingival margin.

Horseshoe crabs are an archetypal chelicerate group with a fossil record extending back to Early Ordovician time. Although extensively studied, the group generally has a low diversity across the Phanerozoic Eonothem. Here, we expand the known diversity of true horseshoe crabs (Xiphosurida) by the description of a new taxon from the Middle Triassic Strelovec Formation of the Slovenian Alps. The mostly complete fossil is preserved as an external mould and assigned to the family Limulidae Zittel, 1881 as Sloveniolimulus rudkini, n. gen., n. sp. The use of landmark and semilandmark geometric morphometrics is explored to corroborate the systematic palaeontology and suggests that the new genus and species are valid. We also provide the first quantitative evidence for the extensive diversity of Triassic horseshoe crabs. We suggest that Triassic horseshoe crabs likely filled many ecological niches left vacant after the end-Permian extinction.

Stained dental materials might affect DIAGNOdent readings and consequently result in false-positive diagnoses of secondary caries. Dental fillings should be polished prior to DIAGNOdent measurement.

Horseshoe crabs are archetypal marine chelicerates with an exceptionally long fossil record. Due to the historical nature of the genus Limulus, which extends back to Linnaeus' descriptions, many horseshoe crab fossils were traditionally placed in Limulus and the family Limulidae. Despite continued research into the accurate placement of species within Limulidae, a systematic outline of characteristics that define limulid genera, specifically using exclusively dorsal characteristics, does not yet exist. However, such an approach is essential as appendage data is rarely preserved in fossil horseshoe crabs. Here we present a systematic review of Limulidae with a focus on dorsal features, and illustrate all accepted limulid species across the 12 genera. Through this descriptive lens, we consider the validity of supposed Limulus species outlined in a recent xiphosurid review. We find evidence for only one fossil Limulus species: Limulus coffini. This revision therefore excludes Limulus from Jurassic-aged deposits. We refer 'Limulus' darwini from the Upper Jurassic (Upper Tithonian) of Poland to Crenatolimulus darwini comb. nov. and 'Limulus' woodwardi from the Middle Jurassic (Aalenian) of England to Mesolimulus woodwardi comb. nov. This highlights that the Limulus evolutionary record is highly constrained and started as recently as the Late Cretaceous. The rare Limulus fossil record emphasizes the current need for conservation of extant species and the importance of thoroughly scrutinizing the morphology of fossil specimens to uncover all facets of the limited limulid evolutionary record.