This commentary evaluates the methodological basis and palaeodietary interpretations presented by Rodríguez-Franco et al. (2026) for Ursus spelaeus from Cueva de Guantes (Palencia, Spain). Although the study provides new isotopic data from a region of the Iberian Peninsula that remains poorly represented in cave bear research, several aspects of the analytical framework raise concerns. These include incomplete assessment of collagen preservation, insufficient description of bioapatite preservation criteria, inconsistencies in isotopic terminology, unresolved chronological discrepancies with previously published dates from the same site, and limited integration of the extensive isotopic literature on cave bears. The interpretation of dietary variability, trophic position, hibernation behaviour, and ontogenetic isotopic patterns is further hindered by the absence of a faunal isotopic baseline and by reliance on hypotheses that are not adequately supported by the available evidence. We argue that the reliability of the isotopic dataset should be reassessed before robust palaeoecological conclusions can be drawn. This case highlights the importance of rigorous quality-control procedures and comprehensive contextualisation in stable isotope studies of fossil mammals.
Petrographic, palynofloral and palynofacies analyses of the samples from coal, associated shale horizons, clay and sandstone from the Permian coal deposits of the Godavari Valley Coalfield (GVC) were made to reconstruct the palaeofloristic and palaeodepositional settings during the sedimentation. The palynofacies analysis revealed the predominant occurrence of degraded organic matter (DOM) along with equidimensional phytoclasts, indicating the forested cover in the vicinity of the flooded palaeomire. The dominant occurrence of the glossopterids also suggests the contribution of gymnospermous vegetation in the swampy settings. Sedimentological analysis of the borehole sediments, coupled with petrography, reveals repeated typical cyclic deposition in a fluvial environment representing a fining upward sequence, in which coarse-grained massive sandstones were deposited at the base, followed by finer sandstone units; heteroliths; grey and carbonaceous shales; and associated coal seams towards the top. The various petrographic indices, palynofacies entities, along with the palynoflora indicate a low-energy swamp to floodplain setting, periodically influenced by fluvial sediment influx. The interpretations of the palynofacies investigation on the ternary diagram suggest that the accumulation of the organic matter occurred in three different palaeoenvironmental settings represented by the forest swamps, flooded palaeomires and oxidised swamps. Collectively, the results suggest that the deposition of the studied sediments of the Barakar Formation occurred under variable energy regimes, but predominantly within low-energy settings. Petrographic studies reflect the mixed provenance of the studied sediments of the Barakar Formation.
The family Cyrtinidae (Brachiopoda) is segregated into two subfamilies: Cyrtininae and Brachiocyrtininae nov. The latter includes Brachiocyrtina n. gen., Cyrtinaella, Hystricocyrtina, and Tecnocyrtina. These taxa differ from Cyrtina and allied genera by the presence of curved ridges and grooves in the dorsal valve, which are interpreted as supports for a sessile jugum and, partially, for the primary lamellae of the brachidium. The implications of this feature are challenging to interpret, aside from its role in alleviating the load borne by the crura to prevent fatal fractures of the brachidium. However, the significant impact on the current system provides sufficient basis for the proposed taxonomic decisions. Brachiocyrtina includes two new Spanish forms: the type species Brachiocyrtina fontebaixana and B. offenbachi, along with many other species previously assigned to Cyrtina, indicating an almost global palaeogeographic distribution for the genus. A sessile jugum was previously unknown among Cyrtinoidea, except for the aberrant Komiella and related genera, and this feature supports its ancestrality and evolutionary success throughout the Devonian to Upper Triassic histories of Cyrtinoidea, Suessoidea, and Spondylospiroidea.
The Upper Devonian terrestrial vegetation of the Iberian Peninsula remains poorly documented. Here, we report the first dispersed-spore assemblage from the Frasnian Bolloncillos Formation of the Iberian Chains, northeastern Spain. Six stratigraphic levels from the upper part of the Lower Member yielded 27 morphotaxa assigned to 19 genera. Biostratigraphically significant elements include Verrucosisporites bulliferus, Retusotriletes rugulatus, Samarisporites triangulatus, Geminospora lemurata, and Aneurospora greggsii. The assemblage is compatible with the broad ovalis–bulliferus Assemblage Zone and with the Verrucosisporites bulliferus–Cirratriradites jekhowskyi and Verrucosisporites bulliferus–Lophozonotriletes media Oppel zones of Western Europe. However, the absence of their nominal index taxa and the long stratigraphic ranges of several recorded species preclude a finer age assignment based on miospores alone. Independent conodont evidence supports a middle Frasnian age, providing the principal chronological constraint for the assemblage. The occurrence of Geminospora lemurata and Aneurospora greggsii indicates that Archaeopteris or closely related archaeopteridalean progymnosperms contributed to the regional vegetation. However, the shallow-marine depositional setting and the absence of quantitative abundance data and local plant megafossils preclude assessment of their dominance or vegetation structure. The morphological diversity of the recovered spores further indicates a heterogeneous terrestrial source flora, although individual morphotypes cannot be assigned confidently to particular habitats or ecological settings. This assemblage provides a well-constrained palaeobotanical record for Frasnian Iberia and establishes a qualitative baseline predating the Frasnian–Famennian boundary for future studies of Late Devonian vegetation change. It broadens the Upper Devonian palaeobotanical record of Iberia and provides a basis for comparison with coeval spore assemblages from Europe.
