BackgroundThe Mesopsychidae is an extinct family of Mecoptera, comprising eleven described genera from Upper Permian to Lower Cretaceous deposits. In 2009, several well-preserved mesopsychids with long proboscides were reported from the mid Mesozoic of Northeastern China, suggesting the presence of pollination mutualisms with gymnosperm plants and highlighting their elevated genus-level diversity. Since that time, additional mesopsychid taxa have been described. However, the phylogeny of genera within Mesopsychidae has not been studied formally, attributable to the limited number of well-preserved fossils.ResultsHere, we describe two new species, Lichnomesopsyche prochorista sp. nov. and Vitimopsyche pristina sp. nov. and revise the diagnosis of Lichnomesopsyche daohugouensis Ren, Labandeira and Shih, 2010, based on ten specimens from the latest Middle Jurassic Jiulongshan Formation of Inner Mongolia, China. After compiling data from these new fossil species and previously reported representative taxa, we conducted phylogenetic analyses and geometric morphometric studies that now shed light on the taxonomy and phylogeny of Mesopsychidae. We also evaluate the recurring origin of the siphonate proboscis in the Mecoptera and propose an evolutionary developmental model for its multiple origins.ConclusionsPhylogenetic and geometric morphometric results confirm the establishment of two new species, each to Lichnomesopsyche and Vitimopsyche. Vitimopsyche pristina sp. nov. extends the existence of the genus Vitimopsyche Novokshonov and Sukacheva, 2001, from the mid Lower Cretaceous to the latest Middle Jurassic. Two methods of analyses indicate an affiliation of Mesopsyche dobrokhotovae Novokshonov, 1997 with Permopsyche Bashkuev, 2011. A phylogenetic analysis of the Mesopsychidae supports: 1), Mesopsychidae as a monophyletic group; 2), Mesopsyche as a paraphyletic group, to be revised pending future examination of additional material; and 3), the independent origin of the proboscis in the Pseudopolycentropodidae, its subsequent loss in earliest Mesopsychidae such as Epicharmesopsyche, its re-origination in the common ancestor (or perhaps independently) in the Vitimopsyche and Lichnomesopsyche clades of the Mesopsychidae. The third conclusion indicates that the proboscis originated four or five times within early Mecoptera, whose origin is explained by an evolutionary developmental model.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-015-0575-y) contains supplementary material, which is available to authorized users.

The head and mouthpart structures of 11 species of Eurasian scorpionflies represent three extinct and closely related families during a 62-million-year interval from the late Middle Jurassic to the late Early Cretaceous. These taxa had elongate, siphonate (tubular) proboscides and fed on ovular secretions of extinct gymnosperms. Five potential ovulate host-plant taxa co-occur with these insects: a seed fern, conifer, ginkgoopsid, pentoxylalean, and gnetalean. The presence of scorpionfly taxa suggests that siphonate proboscides fed on gymnosperm pollination drops and likely engaged in pollination mutualisms with gymnosperms during the mid-Mesozoic, long before the similar and independent coevolution of nectar-feeding flies, moths, and beetles on angiosperms. All three scorpionfly families became extinct during the later Early Cretaceous, coincident with global gymnosperm-to-angiosperm turnover.Animal pollination, most frequently accomplished by insects (1), benefits seed plants by ensuring efficient fertilization without relying on costlier, abiotic modes such as wind and water

Pollinating insects played a decisive role in the origin and early evolution of the angiosperms. Pollinating orthorrhaphous Brachycera fossils (short-horned flies) collected from Late Jurassic rocks in Liaoning Province of northeast China provide evidence for a pre-Cretaceous origin of angiosperms. Functional morphology and comparison with modern confamilial taxa show that the orthorrhaphous Brachycera were some of the most ancient pollinators. These data thus imply that angiosperms originated during the Late Jurassic and were represented by at least two floral types.

Description of the Early Cretaceous (Yixian Formation, China) fauna of Staphylininae and Paederinae rove beetles, and a rigorous (maximum parsimony, maximum likelihood and Bayesian inference) phylogenetic analysis of both extinct and extant taxa resulted in the following discoveries: a stem lineage sister to Staphylininae + Paederinae; a new tribe for Staphylininae, Thayeralinini trib. n.; several extinct species of the extant tribe Arrowinini; extinct basal lineages of the extant tribe Staphylinini; two stem genera of the “Xantholinine‐lineage” (Staphylininae); and recovery of Mesostaphylinus in Paederinae with several new species. It is demonstrated that by the Early Cretaceous, Paederinae and Staphylininae were already diversified into groups, some of which now represent extant tribes but not the branches dominating in the modern biota. While the study of the Early Cretaceous rove beetle fauna pushes the estimated divergence time between Paederinae and Staphylininae down into the Jurassic, it also suggests that presently hyperdiverse groups of Staphylininae originated some time later than the Early Cretaceous. In addition to one new tribe, five new genera (Paleothius, Cretoprosopus, Thayeralinus, Paleowinus and Durothorax) and 17 new species are described in Staphylininae, and three new species of Mesostaphylinus are described in Paederinae. Mesostaphylinus fraternus (incertae sedis) is moved to the genus Thayeralinus (Staphylininae).

Non-avian theropod dinosaurs with preserved integumentary coverings are becoming more common; but apart from the multiple specimens of Caudipteryx, which have true feathers, animals that are reasonably complete and entirely articulated that show these structures in relation to the body have not been reported. Here we report on an enigmatic small theropod dinosaur that is covered with filamentous feather-like structures over its entire body.