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Contemporary intergeneric hybridization and backcrossing among birds-of-paradise
No full textDespite large differences in morphology, behavior and lek-mating strategies the birds-of-paradise are known to hybridize occasionally, even across different genera. Many of these bird-of-paradise hybrids were originally described as distinct species based on large morphological differences when compared to recognized species. Nowadays, these specimens are generally recognized as hybrids based on morphological assessments. Having fascinated naturalists for centuries, hybrid specimens of birds-of-paradise have been collected and the specimens kept in Natural History Collections. In the present study, we utilize this remarkable resource in a museomics framework and evaluate the genomic composition of most described intergeneric hybrids and some intrageneric hybrids. We show that the majority of investigated specimens are first-generation hybrids and that the parental species, in most cases, are in line with prior morphological assessments. We also identify two specimens that are the result of introgressive hybridization between different genera. Additionally, two specimens exhibit hybrid morphologies but have no identifiable signals of hybridization, which may indicate that minor levels of introgression can have large morphological effects. Our findings provide direct evidence of contemporary introgressive hybridization taking place between genera of birds-of-paradise in nature, despite markedly different morphologies and lek-mating behaviors
A depleted mantle source for Neoproterozoic continental rifting in the Seve Nappe Complex, Kebnekaise region, northern Swedish Caledonides
No full textThe Central Iapetus Magmatic Province (CIMP) is a large igneous province (LIP) emplaced in the Baltican and Laurentian paleocontinents that marks the onset of the Caledonian Wilson Cycle. Paleozoic magmatism of the CIMP is preserved in both northeastern America and northern Europe. This study investigates rocks belonging to the hyper-extended margin of Baltica currently found in the Seve Nappe Complex of the Scandinavian Caledonides. Specifically, U-Pb zircon geochronology and whole-rock geochemistry are applied to a migmatitic variety of the Vierručohkka amphibolite of the Mårma Terrane, to the Aurek gabbro, and amphibolite of the Aurek Assemblage exposed in the Seve Nappe Complex in the Kebnekaise region, northern Swedish Caledonides. U-Pb zircon geochronology yields crystallization ages of 626 ± 7 Ma for the protolith of the Vierručohkka amphibolite, and 614 ± 2 Ma and 609 ± 1 Ma for the emplacement of the Aurek gabbro and amphibolite protolith, respectively. A younger age of 599 ± 3 Ma is recorded in the Vierručohkka amphibolite and is interpreted as the age of partial melting and migmatization. The geochemical signatures of the rocks demonstrate crustal assimilation during the emplacement of their protoliths and modification due to prograde metamorphic processes during Caledonian subduction. The Vierručohkka amphibolite and the Aurek Assemblage samples display upper and lower crustal assimilation, respectively. Trace elements (Dy, Sm, Lu, and Y) record the growth of metamorphic garnet, while elevated TiO2 contents record the crystallization of metamorphic rutile. Nevertheless, high field strength elements (HSFE) and ∆Nb suggest a depleted mantle source for the magmas of the protoliths of the investigated rocks. Altogether, geochemical data indicate that the igneous activity recorded in the Vierručohkka amphibolite and the Aurek Assemblage between c. 626–609 Ma is related to continental rifting processes associated with the opening of the Iapetus Ocean
Archaean continental crust formed from mafic cumulates
No full textLarge swaths of juvenile crust with tonalite-trondhjemite-granodiorite (TTG) composition were added to the continental crust from about 3.5 billion years ago. Although TTG magmatism marked a pivotal step in early crustal growth and cratonisation, the petrogenetic processes, tectonic setting and sources of TTGs are not well known. Here, we investigate the composition and petrogenesis of Archaean TTGs using high field-strength-element systematics. The Nb concentrations and Ti anomalies of TTGs show the overwhelming effects of amphibole and plagioclase fractionation and permit constraints on the composition of primary TTG melts. These melts are relatively incompatible element-poor and characterised by variably high La/Sm, Sm/Yb and Sr/Y, and positive Eu anomalies. Differences in these parameters are not indicative of melting depth, but instead track differences in the degree of melting and fractional crystallisation. Primary TTGs formed by the melting of rutile- and garnet-bearing plagioclase-cumulate rocks that resided in proto-continental roots. The partial melting of these rocks is part of a causal chain that links TTG magmatism to the formation of sanukitoids and K-rich granites. Together, these processes explain the growth and differentiation of the continental crust during the Archaean without requiring external forcing such as meteorite impact or the start of global plate tectonics.Research funders and strategic development areas: National Science and Engineering Research Council of Canada (Discovery Grant RGPIN-2020-04692 and Accelerator Grant RGPAS-2020-00069 to M.A.S.)</p
An overview of Miocene to Pleistocene methane-seep faunas from Taiwan: Paleoecology and paleobiogeographic implications
No full textThe invertebrate macrofauna of four methane-seep deposits of Miocene to Pleistocene age from Taiwan is taxonomically evaluated. The Neogene faunas, with one example each from the early and late Miocene and the Pliocene, consist exclusively of one or two large, infaunal lucinid bivalve genera per site, namely Meganodontiaand Lucinoma. The former includes the large, charismatic Pliocene ‘Loripes’ goliath, which is here identified as belonging to the widespread, Neogene to Recent genus Meganodontia. The Pleistocene seep fauna is more diverse, includes extant species like the mytilid Gigantidas horikoshii and Meganodontia aff. acetabulum, unidentified species belonging to Lucinoma and the vesicomyid Isorropodon, and specimens resembling the enigmatic bivalve Sisonia frijellanae, described so far only from the late Miocene of the Philippines; the gastropods could not be identified below family level. The two Miocene seep faunules formed on the shelf of the Eurasian plate, the Pliocene faunule in an upper offshore setting in the Tainan foreland basin, whereas the Pleistocene site with its more diverse fauna formed closer to the shelf edge of the Tainan foreland basin. We suggest that water depth is the most likely driver of this difference in species diversity. The very negative δ13C signature of the seep carbonates of all fossil sites indicates the see page of mostly biogenic rather than thermogenic methane, analogous to the extant seep sites around Taiwan. Biogeographically, the Miocene seep faunas show, with Meganodontia, links to seep faunas from lower to mid-latitudes worldwide (Caribbean Sea, Mediterranean Sea, Philippines, and New Zealand). From the Pliocene onward, biogeographic ties are more restricted to areas in the central Indo-WestPacific Ocean
Early Oligocene kelp holdfasts and stepwise evolution of the kelp ecosystem in the North Pacific
No full textKelp forests are highly productive and economically important ecosystems worldwide, especially in the North Pacific Ocean. However, current hypotheses for their evolutionary origins are reliant on a scant fossil record. Here, we report fossil hapteral kelp holdfasts from western Washington State, USA, indicating that kelp has existed in the northeastern Pacific Ocean since the earliest Oligocene. This is consistent with the proposed North Pacific origin of kelp associated with global cooling around the Eocene–Oligocene transition. These fossils also support the hypotheses that a hapteral holdfast, rather than a discoid holdfast, is the ancestral state in complex kelps and suggest that early kelps likely had a flexible rather than a stiff stipe. Early kelps were possibly grazed upon by mammals like desmostylians, but fossil evidence of the complex ecological interactions known from extant kelp forests is lacking. The fossil record further indicates that the present-day, multi-story kelp forest had developed at latest after the mid-Miocene climate optimum. In summary, the fossils signify a stepwise evolution of the kelp ecosystem in the North Pacific, likely enabled by changes in the ocean-climate system.We acknowledge funding from the Deutsche Forschungsgemeinschaft through grant Ha1166/17-1 to BTH and S.K. This research used resources of the Advanced Light Source, which is a DOE Office of Science User Facility under contract no. DE-AC02-05CH1123. This is University of California Museum of Paleontology Contribution No. 2090.</p
Circumscription of the Ganaspis brasiliensis (Ihering, 1905) species complex (Hymenoptera, Figitidae), and the description of two new species parasitizing the spotted wing drosophila, Drosophila suzukii Matsumura, 1931 (Diptera, Drosophilidae)
No full textBased on host specificity and distribution data, it has been hypothesized that Ganaspis brasiliensis (Ihering, 1905), a natural enemy of the horticultural pest spotted-wing drosophila, Drosophila suzukii Matsumura, 1931 (SWD), was composed of multiple, cryptic species. Parasitoid wasps assigned to the species name Ganaspis brasiliensis and Ganaspis cf. brasiliensis were investigated using a molecular dataset of ultra-con- served elements (UCEs) and morphology. We report strong evidence for the presence of cryptic species based on the combination of UCE data (1,379 UCE loci), host specificity, ovipositor morphology, and distribution data. We describe these new cryptic species as: Ganaspis lupini sp. nov., and Ganaspis kimorum sp. nov. Ganaspis lupini was formerly recognized as Ganaspis brasiliensis G3, and Ganaspis kimorum as Ganaspis brasiliensis G1. These two new species appear to be restricted to the temperate climates, whereas Ganaspis brasiliensis (formerly recognized as Ganaspis brasiliensis G5) has a more pan-tropical distribution. We investigated the characterization of the ovipositor clip of these species, and hypothesize that G. kimorum, which has a reduced ovipositor clip, has an advantage in ovipositing into fresh fruit, still on the host plant, while attacking SWD; as a corollary, G. brasiliensis and G. lupini, which both have a larger ovipositor clip, are better adapted to attacking hosts in softer, rotting fruit on the ground. As Ganaspis kimorum was authorized for release as a biological control agent against SWD under the name Ganaspis brasiliensis G1, the results here have direct impact on the field of biological control.
Vavřínite (Ni2SbTe2) and gold from the Palaeoproterozoic Lainijaur Ni-Cu-Co deposit
No full textDuring the Swedish government project “Secondary Resources”, which aimed to develop classification methods for mine waste and other secondary mineral resources, vavřínite (Ni2SbTe2) and gold were discovered in a polished section made from a mineralized sample taken from the waste rock dumps at the historical Lainijaur Ni-Cu-Co mine in Malå district, northern Swede
Generic revision of the Recent Turridae (Neogastropoda: Conoidea)
No full textThe family Turridae, once considered to encompass the entire diversity of Conoidea, excluding only the cone shells (family Conidae) and the auger shells (family Terebridae), has undergone significant redefinition based on both morphological and molecular data. Prior to this study, it included 15 Recent genera, comprising 209 species. However, a recent comprehensive analysis of an extensive dataset featuring 3,159 cytochrome c oxidase subunit I sequences has unveiled numerous species complexes, new species and previously undiscovered deep lineages. The newly proposed classification of Turridae based on an exon-capture phylogeny recognizes 24 clades, each worthy of genus rank, though only 13 of them had available names. As a result, 11 new genera have been described, namely Thielesyrinx n. gen., Shutogemmula n. gen., Mcleanigemmula n. gen., Pseudogemmula n. gen., Deceptigemmula n. gen., Oliveragemmula n. gen., Powelligemmula n. gen., Kilburnigemmula n. gen., Alisigemmula n. gen., Taylorigemmula n. gen. and Anisogemmula n. gen. With the exception of Thielesyrinx n. gen., species from all of these were previously classified within Gemmula, or Lophiotoma. Notably, some new genera, such as Deceptigemmula n. gen., Kilburnigemmula n. gen., Shutogemmula n. gen. and Taylorigemmula n. gen., cannot be morphologically differentiated, as similar species are found in other genera. Therefore, their distinction relies solely on molecular data. The name Eugemmula is re-instated from the synonymy of Gemmula. Purpuraturris is synonimized with Annulaturris, while Iotyrris with Xenuroturris. In total, we recognize 312 species/primary species hypotheses (PSHs) within the family. Molecular data were obtained for 212 species (among them 15 species complexes comprising in total 45 PSHs), mostly for the first time. A characteristic feature common to the entire family is the position of the relatively narrow anal sinus on the whorl periphery or immediately above it. Radula was examined in representatives of all genera. Although in several cases the radular morphology can aid genus differentiation (e.g. distinguishing Turris from Annulaturris), it is mostly a highly homoplastic structure, with very similar radular types occurring in distantly related genera