Swedish Museum of Natural History
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New subtribal and generic limits in the tribe Athroismeae (Asteraceae) and further disintegration of the subtribe Madagasterinae of the tribe Astereae
No full textThe Astereae subtribe Madagasterinae (Asteraceae) sensu Nesom encompassing four Malagasy genera (Apodocephala, Madagaster, Rochonia and Vernoniopsis) is polyphyletic, as Apodocephala is a member of the Malagasy subtribe Lowryanthina of the tribe Athroismeae. While Madagaster was shown to belong to Astereae, the phylogenetic positions of Rochonia and Vernoniopsis (now Jalantzia) in this tribe remained to be tested with molecular data. Lowryanthinae presently contains Apodocephala with nine species and the monospecific Lowryanthus. The monophyly of Apodocephala remained to be assessed using a comprehensive sampling. The aims were to: (1) assess the phylogenetic placements of Rochonia and Jalantzia (Vernoniopsis) and test the monophyly of Jalantzia; (2) assess phylogenetic relationships within Lowryanthinae; and (3) re-assess the subtribal and generic limits within the tribe Athroismeae. New phylogenetic analyses based on plastid sequence data confirmed the position of Rochonia in Astereae. Jalantzia (Vernoniopsis) was resolved as sister to the subtribe Lowryanthinae and therefore transferred to Athroismeae. A new subtribe, Jalantziinae, is described to accommodate Jalantzia. Apodocephala is paraphyletic with respect to Lowryanthus, which is formally merged with Apodocephala. A description of the emended subtribe Madagasterinae containing Madagaster and Rochonia is presented
Earliest evidence of granivory from China (Shanxi Formation) points to seeds as a food source and nursing habitat for insects in the earliest Permian humid tropical forests of Cathaysia
No full textThree types of plant-insect interactions are identified on seeds from the lower Permian (Asselian) Shanxi and lower Shihhotse formations of the Taiyuan district, North China. This enhances the relatively meagre fossil record of seed predation in global late Paleozoic floras, adding the earliest record of granivory from Cathaysia. The dispersed seeds cannot be attributed with confidence to any particular plant group, but associated fossil leaves belong to a broad spectrum of plants, including Medullosales, Cycadales, Noeggerathiales, Gigantopteridales, Cordaitales, and Voltziales. Among 85 analysed seeds, six showed evidence of predation, referable to three damage types: DT074 and two new damage types that will be added to the forthcoming version of the fossil damage guide (DT274, DT430). These damage features indicate novel strategies of seed exploitation in the earliest Permian of China. The causal agents of the seed herbivory are difficult to resolve with certainty, but possible culprits include representatives of Palaeodictyopteroidea, although we cannot exclude other groups, such as Dictyoptera, Odonatoptera, Archaeorthoptera, Hemipteroidea or early holometabolan insects. The presence of damage features, together with a range of probable defensive structures (hairs, spines, apical horns, and thick integuments), suggests that an active arms race involving insects and plant reproductive structures was already well established by the early PermianSM and AAS are supported by a grant from the Swedish Research Council (VR grant number 2022-03920)</p
Integrative characterisation of the Northwestern European species of Anacharis Dalman, 1823 (Hymenoptera, Cynipoidea, Figitidae) with the description of three new species
No full textThe genus Anacharis Dalman, 1823 comprises parasitoid wasps that target early instars of brown lacewing larvae (Neuroptera: Hemerobiidae). So far, five species were recognised from the Western Palaearctic region, of which four are reported from Northwestern Europe. In this study, we address the Northwestern European species diversity of the genus with an extended integrative taxonomy toolkit. A total of 700 specimens were examined for their external morphology, including the relevant type specimens. For 354 specimens, we obtained CO1 barcode sequences and ap- plied three molecular species delimitation methods. All DNA barcode data are made publicly available via the German Barcode of Life (GBOL) and Barcode of Life Data system (BOLD) database. In addition, we examined images of Wing Interference Patterns (WIPs), examined the male genitalia and performed multivariate morphometric analyses. The analyses revealed two clusters which we describe as the immunis and eucharioides species groups based on differences in DNA barcode, external morphology, WIPs and size of the male genitalia. Furthermore, we complement the diagnosis of the genus Anacharis and describe three new species, Anacharis martinae Vogel, Forshage & Peters, sp. nov., Anacharis maxima Vogel, Forshage & Peters, sp. nov. and Anacharis minima Vogel, Forshage & Peters, sp. nov. Finally, we synonymise A. fergussoni Mata-Casanova & Pujade-Villar, 2018, syn. nov. with A. eucharioides (Dalman, 1818), and we reinstate A. ensifer Walker, 1835, stat. rev., A. typica Walker, 1835, stat. rev. and A. petiolata Zetterstedt, 1838, stat. rev. as valid species. In total, we recognise nine Northwestern European species to which we provide an identification key. The species of Anacharis are morphologically very variable. Morphometric analyses alone did not provide information sufficient to delimit species, neither did analyses of WIPs and male genitalia, with few notable exceptions. Analyses of molecular sequence data proved crucially helpful to reliably delimit species and to find morphological diagnostic characters in a reverse taxonomy approach. For delimiting species groups, all included analyses proved helpful, and we show that exploring an extended integrative taxonomy toolkit can be beneficial for a comprehensive characterisation of species. We acknowledge that a complete overview of species distributions, and characterisation of ecological niches & host records is still required to deeply understand the genus as a whole, yet our results already allow broad access to and inclusion of Anacharis species in downstream biodiversity research.
Hybridization in birds-of-paradise: Widespread ancestral gene flow despite strong sexual selection in a lek-mating system
No full textSexual selection can directly contribute to reproductive isolation and is an important mechanism that can lead to speciation. Lek-mating is one of the most extreme forms of sexual selection, but surprisingly does not seem to preclude occasional hybridization in nature. However, hybridization among lekking species may still be trivial if selection against offspring with intermediate phenotypes prohibits introgression. Here we investigate this further by sequencing the genomes of nearly all bird-of-paradise (Paradisaeidae) species and 10 museum specimens of putative hybrid origin. We find that intergeneric hybridization indeed still takes place despite extreme differentiation in form, plumage, and behavior. In parallel, the genomes of contemporary species contain widespread signatures of past introgression, demonstrating that hybridization has repeatedly resulted in shared genetic variation despite strong sexual isolation. Our study raises important questions about extrinsic factors that modulate hybridization probability and the evolutionary consequences of introgressive hybridization between lekking species
Evolution of Chromosomal Inversions across an Avian Radiation
No full textChromosomal inversions are structural mutations that can play a prominent role in adaptation and speciation. Inversions segregating across species boundaries (trans-species inversions) are often taken as evidence for ancient balancing selection or adaptive introgression, but can also be due to incomplete lineage sorting. Using whole-genome resequencing data from 18 populations of 11 recognized munia species in the genus Lonchura (N = 176 individuals), we identify four large para- and pericentric inversions ranging in size from 4 to 20 Mb. All four inversions cosegregate across multiple species and predate the numerous speciation events associated with the rapid radiation of this clade across the prehistoric Sahul (Australia, New Guinea) and Bismarck Archipelago. Using coalescent theory, we infer that trans-specificity is improbable for neutrally segregating variation despite substantial incomplete lineage sorting characterizing this young radiation. Instead, the maintenance of all three autosomal inversions (chr1, chr5, and chr6) is best explained by selection acting along ecogeographic clines not observed for the collinear parts of the genome. In addition, the sex chromosome inversion largely aligns with species boundaries and shows signatures of repeated positive selection for both alleles. This study provides evidence for trans-species inversion polymorphisms involved in both adaptation and speciation. It further highlights the importance of informing selection inference using a null model of neutral evolution derived from the collinear part of the genome
Bacteria from the Amycolatopsis genus associated with a toxic bird secrete protective secondary metabolites
No full textUropygial gland secretions of birds consist of host and bacteria derived compounds and play a major sanitary and feather-protective role. Here we report on ourmicrobiome studies of theNew Guinean toxic bird Pachycephala schlegelii and the isolation of a member of the Amycolatopsis genus from the uropygial gland secretions. Bioactivity studies in combination with co-cultures, MALDI imaging and HR-MS/MS-based network analyses unveil the basis of its activity against keratinolytic bacteria and fungal skin pathogens.We trace the protective antimicrobial activity of Amycolatopsis sp. PS_44_ISF1 to the production of rifamycin congeners, ciromicin A and of two yet unreported compound families.We performNMR and HR-MS/MS studies to determine the relative structures of six members belonging to a yet unreported lipopeptide family of pachycephalamides and of one representative of the demiguisins, a new hexapeptide family. We then use a combination of phylogenomic, transcriptomic and knock-out studies to identify the underlying biosynthetic gene clusters responsible for the production of pachycephalamides and demiguisins. Our metabolomics data allow us to map molecular ion features of the identified metabolites in extracts of P. schlegelii feathers, verifying their presence in the ecological settingwhere they exert their presumed active role for hosts. Our study shows thatmembers of the Actinomycetotamay play a role in avian feather protection
Greenland Norse walrus exploitation deep into the Arctic
No full textWalrus ivory was a prized commodity in medieval Europe and was supplied by Norse intermediaries who expanded across the North Atlantic, establishing settlements in Iceland and Greenland. However, the precise sources of the traded ivory have long remained unclear, raising important questions about the sustainability of commercial walrus harvesting, the extent to which Greenland Norse were able to continue mounting their own long-range hunting expeditions, and the degree to which they relied on trading ivory with the various Arctic Indigenous peoples that they were starting to encounter. We use high-resolution genomic sourcing methods to track walrus artifacts back to specific hunting grounds, demonstrating that Greenland Norse obtained ivory from High Arctic waters, especially the North Water Polynya, and possibly from the interior Canadian Arctic. These results substantially expand the assumed range of Greenland Norse ivory harvesting activities and support intriguing archaeological evidence for substantive interactions with Thule Inuit, plus possible encounters with Tuniit (Late Dorset Pre-Inuit)