ABSTRACT The rifted Precambrian margin of western Laurentia is hypothesized to have consisted of a series of ~330°-oriented rift segments and ~060°-oriented transform segments. One difficulty with this idea is that the 87 Sr/ 86 Sr i = 0.706 isopleth, which is inferred to coincide with the trace of this rifted margin, is oriented approximately N-S along the western edge of the Idaho batholith and E-W in northern Idaho; the transition between the N-S– and E-W–oriented segments occurs near Orofino, Idaho. We present new paleomagnetic and geochronologic evidence that indicates that the area around Orofino, Idaho, has rotated ~30° clockwise since ca. 85 Ma. Consequently, we interpret the current N-S–oriented margin as originally oriented ~330°, consistent with a Precambrian rift segment, and the E-W margin as originally oriented ~060°, consistent with a transform segment. Independent geochemical and seismic evidence corroborates this interpretation of rotation of Blue Mountains terranes and adjacent Laurentian block. Left-lateral motion along the Lewis and Clark zone during Late Cretaceous–Paleogene time likely accommodated this rotation. The clockwise rotation partially explains the presence of the Columbia embayment, as Laurentian lithosphere was located further west. Restoration of the rotation results in a reconstructed Neoproterozoic margin with a distinct promontory and embayment, and it constrains the rifting direction as SW oriented. The rigid Precambrian rift-transform corner created a transpressional syntaxis during middle Cretaceous deformation associated with the western Idaho and Ahsahka shear zones. During the late Miocene to present, the Precambrian rift-transform corner has acted as a fulcrum, with the Blue Mountains terranes as the lever arm. This motion also explains the paired fan-shaped contractional deformation of the Yakima fold-and-thrust belt and fan-shaped extensional deformation in the Hells Canyon extensional province.

Abstract Zhangsolva is the type genus of the extinct long proboscis family Zhangsolvidae, originally known as a compression fossil from the Laiyang Formation, China. Here we describe a new species Zhangsolva burmensis sp. nov in Cretaceous amber from northern Myanmar. Antennae of zhangsolvids are discussed, and a proposed antennal segmentation of Zhangsolva cupressa is given. Anatomical features of the proboscis are interpreted based on exceptional preservation of the holotype, which are identical to flower-visiting bombyliid flies. This discovery provides important characters for further phylogenetical analysis of the Zhangsolvidae and important evidence for the proboscis function in pollination.

Abstract A new female wasp from Cenomanian Burmese amber was described as Peleserphus qufuensis sp. nov. in the proctotrupoid family Peleserphidae, which emerged in the Late Jurassic–mid-Cretaceous. It provides new data on the diversity of the family in Cenomanian Burmese amber and extends the records to five species.

Abstract The genus Hirsuticyclus Neubauer, Xing and Jochum, 2019 was the first record of an exceptionally preserved land snail with dense periostracal hairs from mid-Cretaceous Kachin (Burmese) amber. Here, we document four newly-discovered shells from Kachin amber, one belonging to the type species Hirsuticyclus electrum Neubauer, Xing and Jochum, 2019 and the remaining three shells belonging to a new species, Hirsuticyclus canaliculatus sp. nov. Well-preserved morphological characteristics of these two species could be clearly demonstrated under light microscopy combined with modern micro-CT scans with computer 3D reconstructions. Our new material of the type species amends the generic diagnosis based on a better-preserved shell including the peristome and operculum. The new species shows distinctive shell characteristics such as numerous spiral keels and a flaring, folded peristome interrupted by two canals. These excellently preserved fossils contribute to our understanding of the morphological diversity and evolution of these ancient members of cyclophoroids.

Abstract A new ommatin beetle, Omma (Coronomma) axsmithi subgen. et sp. nov. (Insecta: Coleoptera: Archostemata: Ommatidae sensu stricto (Cupedidae sensu lato)) is described in mid-Cretaceous Kachin amber from northern Myanmar. The new taxon distinctly differs from nominotypical Omma in possessing a subquadrilateral v. subglobose pronotum, the latter visible in Omma lii from the same deposit. The uniquely preserved male genitalia of the latter are compared and contrasted with extant ommatins and fossil notocupedins. This new analysis suggests that the living Australian ommatin beetles (Omma , Beutelius) may not be as ancient as is sometimes supposed.