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.

A specimen of the genus Pandeopsis Kramp, 1959 was found in surface waters off the northeast Brazilian coast at 10.93°S, 36.48°W. The specimen was assigned to the family Pandeidae on the basis of the presence of more than four hollow marginal tentacles and the absence of divided radial canals, marginal tentacles with terminal cnidocyst cluster, and oral tentacles. Among Pandeidae, the specimen was assigned to Pandeopsis due to the absence of lateral diverticula, centripetal canals, and marginal cirri as well as the presence of more than two marginal tentacles, mesenteries, smooth gonads, and manubrium with a quadrangular base. To the moment, the unique morphological trait that is likely to distinguish the two species of the genus is the presence of medusa buds in the gonads of Pandeopsis prolifera, which was not present in the specimen we found. However, as this is not a strong trait to distinguish species, we consider the present specimen to be Pandeopsis cf. ikarii. This study represents the first record of the genus in the South Atlantic Ocean.

Using ICESat-2 and ArcticDEM strips we track height change in a glacial basin in northern Ellesmere Island Canada. The surface topography dips towards the middle of the basin and ArcticDEM differences show a 1–3 m increase in 2020 summer surface height over an area of 8–10 km2. ICESat-2 heights confirm that each melt season (2019–2024), the height change of melt water at the basin edge matches that over ice in the basin middle. The summer height increase happens at the same time as an upstream drop in surface elevation suggesting yearly episodic subglacial water movement from upstream to a downstream subglacial lake. Melt water drainage occurs in the fall to a particular elevation and apparently follows a path at the northern edge of the basin. These data illustrate subglacial melt water movement both spatially and temporally in rarely obtained detail and are consistent with data from two NASA IceBridge passes.

New, well-preserved specimens of the paracrinoids Wellerocystis and Implicaticystis provide new morphological data. All specimens originate from reef facies in the Kimmswick Limestone (Upper Ordovician, Sandbian–Katian) at a single locality near St Louis, Missouri, USA. Wellerocystis is characterized by an ovoid theca largely composed of imperforate plates arranged in vertical columns lacking pore-structures but with fine granular sculpture; four recumbent branched uniserial ambulacra with up to seven branches in total; a mouth frame of four plates, one of which also contributes to the periproct frame; a sinuous hydropore; and circular gonopore. The stem is unknown; its facet is small and circular, similar to that of Platycystites. Implicaticystis is characterized by a circular, heteromorphic stem, ovoid theca composed of externally concave, perforate plates with foerstepores, internal pararhombs, and a mouth frame of three plates plus two lateral plates each bearing two facets for erect, uniserial, hemipinnate pseudoarms. Foerstepores connect to tubes that pass through the theca near plate sutures. Internal lamellae of pararhombs support thecal plates much as A-frames support ridged rooves. Erect versus recumbent and branched ambulacra evolved repeatedly in pelmatozoans so both are less useful in classifying paracrinoids than presence or absence of unique pore-structures. The sister group of paracrinoids could have included Columbocystis, rhipidocystids, and cryptocrinitids. Columbocystis is commonly mentioned in discussions in this context, but its asymmetrical facets suggest it had biserial feeding appendages, unlike uniserial paracrinoid appendages.

The climatic conditions, particularly the sources of precipitation that enabled extensive glacial growth during the Last Glacial Maximum (LGM) in the European Alps, remain poorly constrained. Here, we apply an inversion method to reconstruct equilibrium line altitude (ELA) fields using glacier footprints, such as the moraines deposited by Alpine glaciers during the LGM. By employing a machine-learning emulator trained on outputs from a glacier-evolution model, we predict glacier maximal thickness. The emulator is integrated into a gradient-based inversion scheme to derive ELA fields consistent with LGM footprints. The results show that the reconstructed ELA fields align with those from previous studies, validating the robustness of our approach. Unlike existing inversion methods, our approach is more general and avoids restrictive assumptions. Notably, by incorporating the transient response of glaciers to climate variability (we do not assume steady state), we show that the cold spell period is crucial for interpreting the reconstructed climate patterns—an aspect previously overlooked. Our findings provide new insights into climatic variability during the LGM, particularly concerning the interaction between precipitation patterns and the cold spell period. Furthermore, the computational efficiency of our method makes it applicable to large-scale paleoclimate reconstructions based on glacier footprints.

A highly diversified fauna of brachyurans is described from the lower Eocene Serraduy Formation of Huesca, northeastern Spain. Fifteen new and first-reported taxa of brachyurans are described including three new genera, ten new species, and five taxa in open nomenclature. New taxa include: Carpilius feldmanni n. sp., Ceronnectes rugosus n. sp., Eohexapus simplex n. sp., Galenopsis ossoi n. sp., Matutsalen rotundus n. gen. n. sp., Microboschettia elegans n. gen. n. sp., Parhalimede antiqua n. sp., Locomius parthenopimimus n. gen. n. sp., Liocarcinus tridentatus n. sp., and Xanthilites robustus n. sp. Five additional genera have been recognized from fragmented material only including Alponella sp., Lovaroides sp., Paromola sp., ?Rhinolambrus sp., and ?Spinirostrimaia sp. Moreover, based on new specimens, we provide new data on Ilerdapatiscus guardiae and Aragolambrus collinsi. New information supports previous considerations about reef settings that are comparable to modern reef ecosystems as environments of diversified decapod crustaceans in the early Eocene.

UUID: http://zoobank.org/a5426acb-1d14-4e37-a843-922c940ac5b2

Lake-terminating glaciers retreat and thin faster than land-terminating glaciers, yet their long-term dynamics remain underexplored. Using multi source–remote sensing data combined with glacier velocity and elevation change datasets, we investigated their distribution and evolution in the Himalaya and Southeastern Tibet from 1990 to 2020. By 2020, 577 lake-terminating glaciers (2561.5 ± 11.8 km2) had been identified, representing ∼2% of all glaciers by number and ∼10% by area. Of these, 246 glaciers maintained contact with proglacial lakes (Type 1 change), while 331 developed new lakes (Type 2 change). Additionally, 173 glaciers detached from lakes (Type 3 change). Variations in glacier–lake contact strongly modulate glacier dynamics. Type 1 change glaciers experienced the largest area loss (73.8 ± 13.1 km2), whereas Type 2 change glaciers showed the greatest average retreat distance (1.06 ± 0.05 km). Among Type 1 change glaciers (>5 km2) with significant velocity trends, 22% accelerated and 78% decelerated, while all Type 3 change glaciers with significant velocity trends consistently decelerated. These findings underscore the pivotal influence of proglacial lake evolution on glacier dynamics, advancing our understanding of glacier–lake interactions on the Tibetan Plateau and beyond.