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Tourmaline as a petrogenetic indicator highlighted in a multicoloured crystal from the gem deposit of Mavuco, Alto Ligoña pegmatite district, NE Mozambique
No full textPlant-insect interactions in the mid-Cretaceous paleotropical El Chango Lagerstätte (Cintalapa Fm., Mexico)—patterns of herbivory during the Angiosperm Terrestrial Revolution
No full textPlants and insects are two of the more diverse and abundant organisms in terrestrial ecosystems. The fossil record of plant-insect interactions offers crucial insights into the coevolutionary dynamics between these groups, shedding light on the intricate relationships that have shaped terrestrial ecosystems. The study of fossil interactions is especially relevant in mid-Cretaceous ecosystems, a time of dramatic changes in the composition of floras and, consequently, in plant-insect relationships. Here, we describe the first suite of plant-insect interactions from the mid-Cretaceous of Mexico. We studied 554 plant fossils from the El Chango Lagerstätte (Cintalapa Formation, Chiapas, Mexico), including vegetative (leaves) and reproductive structures (fruits and seeds). The flora was dominated by gymnosperms (89.3%) followed by angiosperms (10.7%); other groups, such as pteridophytes and bryophytes, were absent. In total, 5.4% of the plant specimens hosted some damage. Angiosperms (all broad-leafed forms), despite being much less common than gymnosperms, expressed more evidence of damage by herbivores (35.6% of specimens damaged). In contrast, the narrow-leafed gymnosperms, the dominant group in the flora, hosted a much lower proportion of herbivory damage (1.8% of specimens damaged). The diversity of damage types (DTs) was relatively low: 14 DTs were identified, corresponding to seven FFGs, including margin feeding, hole feeding, surface feeding, piercing and sucking, oviposition, galling, and mining. Comparison with the other mid-Cretaceous plant-insect assemblages reveals a similar richness of DTs for angiosperms but a lower richness and diversity of DTs on gymnosperms from El Chango. These results indicate preferential herbivory on angiosperms (rather than on the available gymnosperms in the assemblage) by terrestrial arthropods during a period of major changes in the structure of terrestrial ecosystems. However, it is challenging to resolve whether this apparent preference is because insects particularly targeted angiosperms or if the herbivores simply targeted broad leaves in general, since most of the available gymnosperms from El Chango are scale-leafed forms.This work had the fieldworkauthorization permit number 401.1S.3-2024/137 of the Council of Paleontology of the National Archeology Coordination of the National Institute of Anthropology and History (INAH). The author(s) declare financial support was received for the research, authorship, and/or publication of this article. AS and SM are supported by a grant from the Swedish Research Council (VR grant number 2022-03920). AS was also supported by a postdoctoral fellowship from the UNAM (Mexico, ref.: UNAM-DGAPA 2023-2024). SRSCF recognizes financial support from DGAPA-UNAM project IN105522, Conacyt (Conahcyt) project CF61501, and MR-K thanks Conacyt (Conahcyt) a Graduate schoolscholarship, 762397.</p
Graphic and statistical overview of temporal trends and spatial variations within the Swedish National Monitoring Programme for Contaminants in Freshwater Biota (until 2022year’s data)
No full textNew data on the clupeoids of lakes Mai-Ndombe and Tumba, western Democratic Republic of the Congo, using an integrated approach combining morphology and barcoding
No full textMiocene and Pliocene amphibians from Hambach (Germany): new evidence for a late Neogene refuge in northwestern Europe : Fossil amphibians from Hambach
No full textThe Hambach lignite mine in northwestern Germany is a renowned fossil locality, which has yielded remains of several vertebrates dated back to the Middle Miocene and the Late Pliocene. Among these is a recently-described and peculiar proteid urodele, Euronecturus grogu, currently known only from the Middle Miocene level in Hambach. Here, we provide detailed descriptions and identifications of the remaining fossil amphibians (both urodeles and anurans) from the Hambach mine, in total identifying at least 12 Middle Miocene taxa (Cryptobranchidae indet., Palaeoproteus cf. miocenicus, E. grogu, Chelotriton sp., Lissotriton sp., Triturus sp., Latonia sp., ?Palaeobatrachidae indet., Pelobatidae indet., Hyla sp., Pelophylax sp., Rana sp.) and at least nine Late Pliocene ones (Palaeoproteus cf. miocenicus, Mioproteus cf. wezei, Lissotriton sp., Latonia sp., Palaeobatrachus eurydices, cf. Eopelobates sp., Hyla sp., Bufo gr. bufo, Ranidae indet.). The high diversity of amphibians in both Miocene and Pliocene levels at Hambach supports a very humid climate persisting in the area for most of the Neogene, possibly originating a refugium for these animals in northwestern Europe that persisted until the Late Pliocene (and possibly even the Early Pleistocene). Urodeles such as Palaeoproteus and Mioproteus and anurans such as Latonia, the palaeobatrachids, and possibly Eopelobates are all significant occurrences in such a northern latitude at the end of the Pliocene, a period when southward withdrawal of thermophilic animals as well as the first effects of a deteriorizing climate ultimately leading to the Quaternary glaciation had already started in the European continent.We gratefully acknowledge the continuous support of the mining company RWE POWER AG (Cologne) during fieldwork in the Hambach mine.L.M. received support from the SYNTHESYS Project (FR-TAF 2486 and HU-TAF 2724) and is funded by the Alexander von Humboldt Foundation through a Humboldt Research Fellowship.A.V. was funded by a Humboldt Research Fellowship from the Alexander von Humboldt Foundation and by the Agencia Estatal de Investigación through a Juan de la Cierva-Formación grant (FCI2019-039443-I/AEI/10.13039/501100011033) during part of the development of this work. He is now supported by the Secretaria d'Universitats i Recerca of the Departament de Recerca i Universitats, Generalitat de Catalunya, through a Beatriu de Pinós postdoctoral grant (2021 BP 00038).This paper is part of R+D+I project PID2020-117289GB-100, funded by the Agencia Estatal de Investigación of the Spanish Ministerio de Ciencia e Innovación (MCIN/AEI/10.13039/501100011033/).A.V. further acknowledges support by the CERCA Programme/Generalitat de Catalunya and the Agència de Gestió d'Ajuts Universitaris i de Recerca of the Generalitat de Catalunya (2021 SGR 00620).T.M. was funded by the Deutsche Forschungsgemeinschaft (DFG) Special Research Project SFB 350.</p
An early Eocene fish assemblage associated with a barite deposit in the lower part of the Crescent Formation, Olympic Peninsula, Washington State, USA
No full textAbundant shark and rare actinopterygian teeth are reported from a locality within the early Eocene (Ypresian) lower part of the Crescent Formation exposed in the Hamma Hamma River valley on the eastern Olympic Peninsula, Washington State, USA. This part of the Crescent Formation is predominantly submarine volcanic basalt with some sedimentary interbeds deposited in deep water. The teeth are derived from sediments that appear to directly overlay and in places interfinger with the margins of an anomalous lenticular barite deposit; one tooth was found in the barite. Genera represented include deep-water taxa (aff. Chlamydoselachus, Mitsukurina, Notorynchus, Odontaspis) and open marine, epipelagic sharks (Alopias, Brachycarcharias, Jaekelotodus, Macrorhizodus, Otodus, Striatolamia). The only other fossils found were two fragmentary shark vertebrae, numerous shark dermal ossicles, a single teleost tooth (Egertonia) and abundant, minute valves of a discinid brachiopod. This is the first report of macrofossils from the lower part of the Crescent Formation and the only early Eocene shark assemblage described from the North Pacific Basin. The shark assemblage also corroborates paleodepositional interpretations of the lower Crescent Formation as being in part ancient volcanic seamounts during early Eocene time. Fossils used in this study were collected under USFS permit (R6-OLYMPIC-MGM-FY23-001). This research was funded in part by the Austrian Science Fund (FWF) [P 33820] to JK, and in part bythe Swedish Research Council (Vetenskapsrådet; 2016-03920) to SK. Open access funding provided by Swedish Museum of Natural History. </p
Detection of in situ resinous traces in Jurassic conifers from floras lacking amber
No full textAmber deposits are rare in Jurassic successions, occurring in small quantities, whereas Lower Cretaceous strata host many substantial and commonly fossiliferous amber deposits worldwide. Minor amounts of Early Jurassic amber have been reported from Italy, and small amounts of Late Jurassic amber are known from Lebanon, Jordan and Thailand. Other Jurassic amber deposits that require reinvestigation of their age and provenance have also been reported from Denmark and France. Few of these amber deposits contain fossils, the others lack inclusions, suggesting a ‘Jurassic amber gap’ in the fossil record. Here, we surveyed fossil plant collections held at the Swedish Museum of Natural History, Stockholm, for amber and amber producing plants from Jurassic floras. We focused on the collection of plants from Shaanxi, China and the Middle Jurassic floras of Iran and Afghanistan from the H.-J. Schweitzer collection. Using a hand-held UV light microscope, we scanned the collections for resinous remains as ambers can show autofluorescence with UV light, but found no dispersed amber fragments or droplets. Some researchers refer to fossilized resin within plant tissues under that name to differentiate it from exuded resins preserved as amber, and we follow this convention. We identified a conifer fragment of Elatocladus sp. from China with in situ rods of resin preserved in the leaves and a unique conifer twig (Elatides sp.) from Afghanistan with tiny linear resin traces in leaves that were only visible via autofluorescence with UV light. These resinous traces likely define the former position of resin canals in the leaves, but the resin is not preserved as in situ rods. Instead, it has impregnated the coalified mesophyll, likely during fossilization, to form thin lines (chemical ‘ghosts’ of preserved resin) within the conifer leaf remains.The research visit of MC and LJS to the Swedish Museum of Natural History (NRM)and support for MS was funded by the Swedish ResearchCouncil (VR), grant number NT7-2016 04905 to MS. MChas further been supported by a Lise Meitner fellowshipfrom the Austrian Science Fund (FWF), grant doi: 10.55776/M3168. Funding is also acknowledged from the Knut and Alice Wallenberg Foundation, KAW-2020.0145 and from the Swedish Research Council VR grants 2019-4061 (toVV) and 2022-03920 (to SM).</p
Revision and biostratigraphic implications of Thore Halle’s Permian plant fossils from the Falkland (Malvinas) Islands
No full textThe Permian fossil plant assemblages from the Lafonia Group on the Falkland (Malvinas) Islands collected by Thore Gustav Halle on the 1907–1909 Swedish Expedition to Patagonia and Tierra del Fuego are re-described and their systematic placement revised. Two species of sphenophytes based on foliage and one on axial remains are recognized. Eight morphotypes of Glossopteris are differentiated usingmore rigorously defined criteria than Halle’s original character sets. A single species each of cordaitaleans and conifers are recognized. The absence of ferns and lycophytes may indicate significant taphonomic filters on the composition of the plant assemblages. Re-assessment of the characters of the fossil woods and their nomenclatural and taxonomic problems suggests that only a single species is recognizable in the assemblage. Several of the wood and leaf species bear evidence of fungal degradation along with a broad array of arthropod herbivory and oviposition damage that add to the diversity of biotic interactions documented in the middle–high southern latitude Glossopterid Biome of the late Paleozoic. The ages of the various fossiliferous units on the Falkland (Malvinas) Islands remain equivocal, but similarities with chronostratigraphically constrained leaf assemblages from the Karoo Basin, South Africa, suggest that the Bay of Harbours Formation (uppermost unit of the Lafonia Group) is referable to the upper Guadalupian to lowermost Lopingian.S.M. was funded by grants from the Swedish Research Council (VR grant numbers 2018-04527 and 2022-03920). R.P was funded by Genus (DST-NRF Centre ofExcellence in Palaeosciences; Grant). B.C. was funded by CONICET Postdoctoral External Scholarship Program for Young Researchers, Resolution D.N° 4279/2016. </p
Biotite dissolution kinetics at pH 4 and 6.5 under anaerobic conditions and the release of dissolved Fe(II)
No full textDissolution of biotite, the main Fe-bearing mineral in granitic bedrock, is of particular importance for the remediation of reducing conditions after the ingress of oxygen, such as after mining activities or the construction of deep repositories for toxic waste. This study investigated the leaching of biotite of size fraction 0.053–0.075 mm under anaerobic conditions at room temperature and pH 4 and 6.5 for a maximum of 160 days. The changes in the concentrations of the major elements in the leaching solutions were monitored. In addition, Fe(II) was analysed separately. pH-independent rate coefficients kH+ were 4.8∙10−10, 6.9∙10−10, 6.3∙10−11, and 1.0∙10−12 mol1-n m−2 s-1, for Fe, Fe(II), Mn, and Si, respectively. The corresponding proton reaction orders nH+ were 0.61, 0.63, 0.33, and 0.09, respectively. The corresponding parameters for Al were not evaluated because of a suspected gibbsite precipitation at pH 6.5. The dissolution of biotite was found to be incongruent (non-stoichiometric) with respect to both the dissolving elements and the pH value. At pH 4, the dissolution was dominated by the octahedral layer element Fe, whereas at pH 6.5, the dissolution of the tetrahedral element Si dominated. There was no evidence of secondary phase formation, and the biotite leaching rates were consistent with those reported in previous studies conducted under aerobic conditions. In addition, the Fe(III)/Fetot ratio of biotite remained essentially unchanged before and after the experiment. This indicates that the anaerobic conditions alone have little effect on the rate and nature of biotite dissolution, although they may influence vermiculite formation. Therefore, biotite dissolution rates previously obtained under aerobic conditions may also be valid under anaerobic conditions
Uranium Repartitioning during Microbial Driven Reductive Transformation of U(VI)-Sorbed Schwertmannite and Jarosite
No full textThis study exposes U(VI)-sorbed schwertmannite and jarosite to biotic reductive incubations under field-relevant conditions and examines the changes in aqueous and solid-phase speciation of U, Fe, and S as well as associated microbial communities over 180 days. The chemical, X-ray absorption spectroscopy, X-ray diffraction, and microscopic data demonstrated that the U(VI)-sorbed schwertmannite underwent a rapid reductive dissolution and solid-phase transformation to goethite, during which the surface-sorbed U(VI) was partly reduced and mostly repartitioned to monomeric U(VI)/U(IV) complexes by carboxyl and phosphoryl ligands on biomass or organic substances. Furthermore, the microbial data suggest that these processes were likely driven by the consecutive developments of fermentative and sulfate- and iron- reducing microbial communities. In contrast, the U(VI)-sorbed jarosite only stimulated the growth of some fermentative communities and underwent very limited reductive dissolution and thus, remaining in its initial state with no detectable mineralogical transformation and solid-phase U reduction/repartitioning. Accordingly, these two biotic incubations did not induce increased risk of U reliberation to the aqueous phase. These findings have important implications for understanding the interactions of schwertmannite/jarosite with microbial communities and colinked behavior and fate of U following the establishment of reducing conditions in various acidic and U-rich settings