Investigating magmatic processes in exhumed lower continental crust is often complicated by metamorphic and tectonic overprints postdating magma emplacement. To decrypt these requires integrated structural and petrological analyses at multiple scales. This study provides a new Virtual Outcrop Model (VOM) combined with structural and petrographic analyses of a ∼83 m long outcrop within the Mafic Complex of the Ivrea-Verbano Zone (IVZ), Italy, representing an exhumed section of the lower continental crust. The outcrop is mainly composed of hornblende gabbronorites with variabilities in garnet textures and modal abundances. The main foliation shows local changes in orientation but is generally sub-parallel to the Insubric line. We identify previously unreported olivine-hornblende garnetite and garnet hornblendite lenses, often associated with anorthosite lenses by gradual contacts. Garnet-olivine gabbro occurs in the northern and southern zones of the outcrop. A metamorphic overprint is indicated by: (i) granoblastic to polygonal textures with triple junctions, (ii) rutile exsolution in orthopyroxenes, (iii) hercynite exsolution in plagioclase and (iv) coronitic garnet formed around oxides and olivine. Previously unreported mafic pegmatites crosscut by pseudotachylytes were also identified. Alpine-related faults and shear structures crosscut all lithologies, but detailed field observations combined with analyses of the VOM facilitated the conclusion that the original, pre-alpine spatial relationships between the different magmatic units have not been significantly altered. The lithological sequence and mineralogical variability of this outcrop can, therefore, be used for future detailed studies to assess the primary magmatic processes and subsequent metamorphic pressure-temperature path that affected this portion of the lower continental crust.

Two assemblages of Floian graptolites from the Acoite Formation at a new section on the western flank of the Cordillera Oriental, Jujuy Province, referred to as El Moreno, are presented. The first assemblage includes Acrograptus spp., Baltograptus jacksoni Rushton, Baltograptus cf. jacksoni Rushton, Baltograptus sp. and poorly preserved tetragraptids. The second assemblage comprises Baltograptus deflexus? (Elles & Wood) and Baltograptus minutus (Törnquist). The presence of Baltograptus jacksoni and Baltograptus minutus allows for the identification of the eponymous biozones, indicating a middle to late Floian age for the studied strata. This contribution confirms the occurrence of Baltograptus jacksoni in Argentina. In addition, previous records of Floian graptolites from northwestern Argentina are revised, thus supporting the proposal to use the Baltograptus jacksoni and Baltograptus minutus zones in the Cordillera Oriental of Argentina. This enables regional correlations with equivalent levels throughout the Central Andean Basin, as well as more precise intercontinental correlation.

Abrupt appearance of the dikelocephalid trilobite genus Osceolia in later Cambrian strata of the upper Mississippi Valley immediately above a flooding surface is succeeded by widespread regional occurrence among approximately eight parasequences in the early part of a falling stage systems tract. All of Osceolia’s sclerite types are illustrated for the first time. The taxonomy is revised to recognize two species, of which O. tumerispina is new and known only from a dolomitic horizon at a single locality. All five of Ulrich and Resser’s (1930) Osceolia species are synonymized within O. osceola (Hall, 1863), a species widespread in regional dolomitic mudstones and feldspathic sandstones. Osceolia osceola shows notable polymorphism in the presence of an axial ledge in the anterior cranidial border. Holaspid ontogenetic variation evident within bedding-plane collections of O. osceola scales with that occurring among collections and across facies. Collection-related morphological differences among the samples beyond those related to size are subtle. The occurrence of larger individuals in more distal settings may reflect ontogenetically related habitat preference. Osceolinae Ulrich and Resser, 1930 is rejected. The closest relatives of the two Osceolia species may occur outside of the upper Mississippi Valley. Material of a local, stratigraphically older, and possibly related Ulrich and Resser 1930 nomen nudum is figured and described for the first time. Osceolia’s cranidial morphotype was converged upon several times during the evolution of Cambrian trilobites among relatives both phylogenetically close and distant.

UUID: http://zoobank.org/bdd2cf1b-331f-4204-8957-eadce195610d

Monitoring snow depth in Antarctica is essential for understanding permafrost dynamics and soil thermal regimes. This study assesses the performance of low-cost, high-resolution, autocleaning ultrasonic sensors (MB7574-SCXL-Maxsonar-WRST7), powered by lithium D-type battery Geoprecision-Box dataloggers, in the South Shetland Islands. Traditional methods for estimating snow thickness, such as air temperature sensors in snow stakes, are economical but involve high maintenance costs and various complexities. To address these issues, we deployed ultrasonic sensors across 12 stations on Livingston and Deception islands from early 2023 to early 2024. Located at altitudes from 15 to 274 m above sea level and with varying wind exposures, these devices demonstrated notable durability and reliability, with only one sensor failure occurring due to structural damage. Data processing involved using an R script to filter out noise, and this process provided accurate hourly snow-depth measurements and revealed significant spatial and altitudinal variability, with depths ranging from 20 to 110 cm. Snow accumulation began in April and peaked in August and October, with major snowfall events contributing temporarily to snow depth but not to long-term accumulation. Our findings suggest that these sensors, as low-cost alternatives, could be integrated into networks such as the Global Terrestrial Network for Permafrost (GTN-P), supporting climate and permafrost studies.

This work expands the knowledge on the diversity of Ordovician cephalopod assemblages of peri-Gondwana by describing 16 straight-shelled, annulated and/or reticulately ornamented specimens from the late Darriwilian and late Katian strata of the Prague Basin (Central Bohemia). Preservation facilitated the micro-CT investigation of internal shell structures in one of the specimens; in other specimens, the siphuncle and septa are not preserved, and these specimens are thus left in open nomenclature. In total, six species are recognized with one new species established: Anthoceras? sp. A, Anthoceras? sp. B, Sactorthoceras pustulatum new species, Dawsonoceras? sp. indet., Kionoceras? sp. indet., and Palaeodawsonocerina obscurum new combination. In addition, the holotype of Orthoceras evictum was examined and re-interpreted as a conulariid rather than a cephalopod. Paleogeographically, these taxa indicate mixed Baltican, Avalonian and peri-Gondwanan affinities for the late Darriwilian and late Katian cephalopod assemblages.

UUID: http://zoobank.org/fcf79203-e864-47ed-bf71-12f475fa55a9

The phylogenetic relationships among arthropods remain contentious because morphological studies face challenges in resolving certain branches. Particularly difficult are relationships within and between the stem arthropods, owing largely to too few well-preserved fossil representatives. Additional fossil evidence, particularly from exceptional deposits like the Silurian Waukesha Lagerstätte in Wisconsin, helps to bolster our views on the evolutionary history of arthropods by providing well-preserved examples of novel taxa that could fit between early diverging stem-arthropod clades and modern euarthropods, thus building possible bridges between the two. Formed in karstification-induced troughs of the Manistique Formation paleoslope, the Waukesha Lagerstätte preserves a unique biota of organisms from the Telychian Age, mostly through secondary precipitation of francolite. Perhaps most well known from this deposit are the many peculiar and enigmatic arthropod taxa that could help resolve early arthropod cladistic relationships. We add to the growing body of work on the diversity, phylogeny, and taxonomic descriptions of the Waukesha biota by detailing a previously unnamed bivalved arthropod, informally called ‘the butterfly animal’ in past literature—which we here designate as Papiliomaris kluessendorfae n. gen. n. sp. We also conducted a Bayesian phylogenetic analysis that placed several recently described Waukesha taxa as basal members of the ‘Mandibulate’ clade within the Euarthropoda.

UUID: http://zoobank.org/c1d6f1dc-d35f-420c-aa57-2c8983f9779e

Benthic gastropods are not commonly useful for biostratigraphic zonation. The gastropod genus Plocezyga is abundant throughout the marine units of the Desmoinesian through Virgilian Pennsylvanian strata in the United States. The protoconch of Plocezyga gives evidence that it had a planktonic time within its life cycle, which would give it a wider regional distribution. It has been found that Plocezyga is able to biostratigraphically zone the Pennsylvanian of the United States by use of first-occurrence range zones. The upper Atokan stage through the Virgilian Stage can be zoned using of the first occurrences of Plocezyga conica, P. excellens, P. ampla new species, P. costata, P. subquadrata, P. ornata, P. acuminata, P. obscura, and P. procera new species. The lower and upper boundary of the Desmoinesian as well as the lower boundary of the Missourian Stage are defined by these gastropod zones. Six new species are proposed: Plocezgya ampla from upper Desmoinesian units; Gamizyga lenterotunda from Missourian units; and Plocezyga pingurestis, Plocezyga procera, Cyclozyga promohumera, and Cyclozyga diversarevolvi from Virgilian units.

UUID: http://zoobank.org/d070c5ad-b65f-4ab1-842f-36058704a335

Precambrian organic-walled microfossils preserved in fine-grained sedimentary rocks constitute the earliest fossil record of eukaryotic life. The Mesoproterozoic–Neoproterozoic transition coincided with major innovations in the evolution of early eukaryotes, including the radiation of crown-group lineages, represented in these rocks by candidate red algae, green algae, and fungi. However, the diversity of these early eukaryotes is yet to be fully explored. Here, we present a systematic description of the microfossil assemblage preserved in exceptional detail within sedimentary phosphatic nodules and bands in the Diabaig Formation of the ca. 1-Ga Torridon Group of northwest Scotland. Recent work has highlighted the lacustrine or estuarine nature of its depositional environment and confirmed that these fossils may include the oldest known non-marine eukaryotes. We identified 11 morphotaxa from newly collected material, including the new genus and species Minimarmilla multicatenaria, two undoubted eukaryotes, and two probable eukaryotes. The latter include Pterospermopsimorpha sp., and a new network-forming unnamed taxon. These microfossils present an important window on eukaryotic diversification in non-marine aquatic environments during the Mesoproterozoic–Neoproterozoic.

UUID: http://zoobank.org/5829c401-04fc-4229-9136-3963275826c6

The presence of the zebrette goby (Tigrigobius zebrellus) is reported for the first time in the Canary Islands, as well as in the eastern Atlantic. A new established colony around the floating docks of the Marina Santa Cruz de Tenerife harbour has been studied. Over two hundred individuals at different developmental stages have been counted. Its restricted distribution and population characteristic show that it has an established population but with no evidence of expansion to its vicinity. Our study indicates that the population of this exotic species could be easily eradicated to avoid any possible negative impact on local benthic communities. However, if such measures are not soon implemented by the local government this study can also be used as the early invasion stage of an exotic fish species across the Canary Islands.