Lead (Pb) has progressively become ubiquitous due to widespread use. The liver represents a target of Pb toxicity due to its central role in metabolism and detoxification. The mechanisms of Pb hepatotoxicity have not yet been fully elucidated, although oxidative stress and iron dysregulation suggest the involvement of the ferroptosis pathway. It has been hypothesized that exposure to environmental Pb concentrations induces the activation of ferroptosis as a mechanism involved in Pb hepatotoxicity, an iron-mediated regulated cell death. To test this hypothesis, we exposed adult zebrafish to environmentally relevant Pb concentrations (2.5 and 5 μg/L), combining ultrastructural analysis (TEM) with the study of key markers of ferroptosis (GPX4, SLC7A11, NRF2, KEAP1 and ACSL4). The results demonstrated that Pb exposure induced dose-dependent and progressive mitochondrial damage in hepatocytes, characterized by loss of cristae and membrane rupture. At the same time, consistent with a ferroptotic molecular profile, increased expression of ACSL4, reduced levels of the protective factors NRF2, KEAP1 and SLC7A11, and altered expression of GPX4 were observed. Overall, our data collectively identify ferroptosis as a pathogenic pathway in Pb-induced hepatotoxicity.

Hippolyte inermis is a protandric hermaphroditic shrimp widespread in most Mediterranean seagrass meadows. It has a complex life cycle, because an unknown compound present in benthic diatoms (Cocconeis spp.) induces an early sex reversal in its post-larvae upon ingestion. This change occurs due to the disruption of the androgenic gland (AG) germ cells. To elucidate the molecular mechanisms behind this unique example of sexual plasticity, we isolated sex-specific genes from the transcriptomes of shrimp collected at various stages of their life cycle. Using Real-Time qPCR, we measured, in wild adults, the expression levels of the Insulin-like Androgenic Gland hormone (Hi-IAG), Vitellogenin-1 (Hi-VG1), two uncharacterized male and female genes (Hi-UCM and Hi-UCF), and two uncharacterized male and female eyestalk genes (Hi-UCMe and Hi-UCFe). Further, the expression of these genes was evaluated in shrimp cultured in the laboratory, after the ingestion of bioactive diatoms, to identify potential molecular markers. Only Hi-VG1 and Hi-UCM showed a consistent relationship with the phenotype of adults, according to their sex. Subsequently, we investigated the physiological and developmental expression patterns of Hi-VG1 and Hi-UCM, along with several Vitellogenin variants, across a range of developmental stages, to reveal the mechanisms of sex regulation. While the results revealed complex response patterns, they lay the groundwork for understanding the link between key gene expression and sexual determination and maturation in decapod crustaceans.

The northern Ionian coast of Calabria (Southern Italy) represents a largely unexplored marine region, increasingly impacted by anthropogenic pressures yet lacking a comprehensive environmental assessment. This study combines a critical review of available literature with a five-year (2015–2020) experimental dataset of environmental parameters collected in the Villapiana coastal sector, providing the first integrated characterization of the study area, and extending current knowledge on northern Ionian Calabrian coast. Water samples from three offshore stations and sediment samples from one subcoastal station were analyzed for physico-chemical parameters, nutrients, and contaminants. Results highlight a warming trend in surface waters and a notable rise in pH, contrasting with the general acidification reported across the Mediterranean Sea. Chlorophyll-a peak shifted to greater depths, suggesting a deepening of the photic zone. Nutrient levels remained constantly low across depths and stations, confirming the oligotrophic nature of the area. While most pollutants were below detection limits, lead concentrations in seawater exceeded environmental quality standards in a single time point. These findings underline the need for ongoing and standardized monitoring to support conservation strategies and assess future changes in this sensitive coastal ecosystem.

Organic UV filters are widely used in personal care products and are increasingly being detected in aquatic environments, where they may pose a risk to aquatic organisms. Avobenzone (AVO) is one of the most widely used of these compounds worldwide. The European Commission has included it among substances to be systematically monitored across EU Member States due to concerns regarding its environmental fate and potential ecological risks. The available literature indicates that avobenzone can cause adverse biological effects in a wide range of aquatic species. However, research into the effects of avobenzone on fish is extremely limited, and no data on gill toxicity are currently available. In this study, we investigated the effects of two environmentally relevant concentrations of AVO (3 and 9 μg/L) on the gills of zebrafish (Danio rerio) under short-term (4 days) and long-term (21 days) exposure conditions. Morphological, ultrastructural, morphometric and molecular endpoints were evaluated to provide a comprehensive assessment of AVO-induced toxicity. Our results demonstrate that exposure to AVO induces pronounced, time- and dose-dependent alterations in gill tissue. These include chloride cell hypertrophy, epithelial lifting, macrophage proliferation and increased filament thickness and lamellar width, alongside reduced lamellar length. Furthermore, AVO exposure was found to significantly modulate the expression of genes involved in osmoregulation (atp1a1a.1 and aqp3a), the oxidative stress response (sod and cat) and apoptosis (casp3, casp8 and casp9). Overall, our findings provide novel evidence of avobenzone-induced gill toxicity in adult zebrafish and contribute to improving the environmental risk assessment of UV filters in aquatic ecosystems. Additionally, the information presented here underscores the importance of integrating morphological and molecular approaches when evaluating the toxic potential of emerging contaminants.

Karyotype diversification and chromosome mutations (or macromutations) such as inversions, fusions, and fissions represent understudied factors of biological evolution. We present in this study one of the first experimental cytogenetic analyses on the Malagasy day geckos of the genus Phelsuma. A molecular analysis was performed using a trait of the mitochondrial 12S and a comparative chromosome study with traditional Giemsa coloration, Ag-NOR staining and sequential C-banding (C-banding + Giemsa + fluorochromes) on nine individuals of Phelsuma from different localities. The molecular analysis allowed unambiguous identification of three species (P. lineata, P. laticauda, and P. standingi), while two additional samples likely belong to a still formally undescribed lineage, here named Phelsuma cf. flavigularis. The comparative cytogenetic analysis showed that three of the studied species (P. lineata, P. laticauda and P. cf. flavigularis) have a karyotype composed of 2n = 36 with all acrocentric chromosomes gradually decreasing in length. In turn, P. standingi showed a karyotype of 2n = 32 with two large metacentric pairs (probably originated from two chromosome fusions) and fourteen acrocentric pairs. NOR loci were alternately localized in the study samples on the first (in P. laticauda), the third (in P. standingi), and the 15th chromosome pair (in P. lineata). Sequential C-banding indicated a scarce amount of heterochromatin in all species analyzed, mostly on the centromeric, pericentromeric and telomeric regions of most chromosome pairs. Adding this new data to those available from the literature, we show that common evolutionary trends characterize several clades of the Malagasy Gekkoninae.

ABSTRACT The pine processionary moth Thaumetopoea pityocampa (Denis & Schiffermüller, 1755) is widely distributed in Mediterranean areas where its larval phases colonize different Pinus species, often inducing a complete defoliation. According to the most common pattern in Insects, T. pityocampa shows a size dimorphism, with males being smaller than females. Despite its great socioeconomic relevance, the morphological characteristics of this species are still not well-documented. Available studies mainly focus on general morphology, biological cycle and ecological traits, thus leaving a knowledge gap on this topic. Here, we provide for the first time a detailed morphological description of T. pityocampa adults with particular emphasis on sexual dimorphism through an in-depth analysis under both stereomicroscope and scanning electron microscope. The shape and distribution of scales in the wings of males and females have been evaluated to reveal putative differences in their morphology and/or location and the hindwings of males have a much greater number of hairy scales. Since insects rely on their antennal sensilla to accomplish vital cues, including mate selection and host plant recognition, we investigated the antennal arrangement and the distribution of sensilla in both sexes. A notable dimorphism in the length of the lateral branches of the antennae was highlighted but no differences were observed in the general distribution of the sensilla. Males possess exclusively one type of trichoid sensilla (type 1), which are longer than those observed in females.

The invasive Chlorophyta Caulerpa racemosa raises ecological problems in the Mediterranean Sea both in terms of native algal diversity and toxicity to aquatic organisms. In this paper, we determined the effects of Caulerpa on a sessile, filter-feeding animal, the mussel Mytilus galloprovincialis. By using different histological approaches, we investigated the response of mussel tissues to increasing amounts of Caulerpa. The recorded data showed a multisystem discomfort of M. galloprovincialis to C. racemosa, with structural alterations in the gills, digestive gland, and mantle. Alterations in tissue organization, such as altered thickness of the gill epithelium, appearance of lipofuscin granules in the gills, cellular disorganization of the digestive glands, and hypertrophy of mantle cells are all morphological aspects potentially attributable to the oxidative stress caused by C. racemosa. This mechanism could also underline the most worrisome damage recorded in Caulerpa-exposed specimens, i.e., degeneration of oocytes and altered differentiation of sperm cells with severe gonadal disorganization; these alterations over time could pose a major risk to the survival of adult mussels by also affecting their reproductive fitness, with potential consequences for the continuation of the species.

The widespread and uncontrolled application of neonicotinoid pesticides represents a major threat to freshwater ecosystems, especially those near agricultural lands and farms. Here, we determined for the first time the mean lethal concentration (LC50–96 h) of acetamiprid on bleak Alburnus alburnus juveniles and investigated the effect on gills of two environmentally relevant concentrations after short-term exposure (96 h). After defining the LC50 value (34.546 mg/L), we evaluated the effects of two low concentrations (150 and 300 µg/L) through a histological examination and molecular evaluation of Na+/K+-ATPase expression in gills. No morphological alterations were observed in the control group. Severe structural modifications were observed in samples exposed to both tested concentrations, including hyperplasia and hypertrophy of chloride cells, epithelial detachment and aneurysm formation, which are recognised as a common and early response of freshwater gills to chemical insults. Exposure to the highest tested concentration induced more severe damage, with the appearance of necrotic pavement cells and degeneration of pillar cells. Na+/K+-ATPase downregulation was observed following the exposure to both tested concentrations. Our results highlight the importance of expanding the panel of ecotoxicological tests required to approve agrochemical compounds and using different diagnostic tools for an in-depth examination of xenobiotic toxicity.

Microplastic (MP) pollution has emerged as a major environmental challenge, with polyethylene (PE) being among the most frequently detected microplastics currently found in marine ecosystems. Due to their filtering behaviour and constant exposure to contaminants, bivalve molluscs are particularly susceptible to MPs uptake, also representing a potential vector for the transfer of MPs to humans through the food chain. As the primary site of respiration and feeding, the gills represent a key organ for evaluating MP toxicity. This study provides evidence of histopathological and molecular alterations induced by environmentally relevant concentrations of polyethylene (PE, 20 and 100 μg/L) in the gills of Mytilus galloprovincialis after 14 and 21 days of exposure. Here, we also investigated the potential protective role of co-exposure with Chlorella vulgaris, a nutrient-rich microalga that has recently attracted attention for its bioremediation capacity.Exposure to PE resulted in severe gill alterations, including epithelial detachment, hyperplasia, granulocyte infiltration and haemolymphatic vessel dilation, with severity increasing in a dose- and time-dependent manner. At the molecular level, PE induced the upregulation of sod, cat, and gst, and the downregulation of hsp70. Co-exposure with C. vulgaris mitigated the onset of numerous alterations, although it did not fully prevent gill damage. C. vulgaris also reduced PE-induced oxidative stress, as evidenced by lower expression levels of stress-related genes. Overall, our findings demonstrate the protective role of C. vulgaris against PE-induced toxicity, supporting its potential use as a dietary supplement and bioremediation tool in aquaculture.

Madagascar is one of the world's most prominent biodiversity hotspots and is characterized by exceptionally high amphibian diversity, with 429 currently described, mostly endemic species. However, cytogenetic research on Malagasy amphibians has been conducted only intermittently over the years. Previous studies, mostly using conventional staining and banding methods and often confined to single taxa or isolated families, have provided only partial insights into the karyotype evolution and genome organization of the major Malagasy clades. In this contribution, we present the first comprehensive synthesis of all available cytogenetic data on Malagasy anurans, including chromosome number and morphology, heterochromatin distribution, and chromosomal markers across the major endemic Malagasy families. By integrating and comparing results from decades of scattered studies, this review reveals consistent patterns of chromosomal diversification and identifies evolutionary trends associated with speciation and adaptive radiation in Malagasy amphibians. Overall, native Malagasy amphibian species can be subdivided into two main karyotype groups: the first includes karyotypes with only biarmed chromosomes (Heterixalus, Ptychadena, Boophis, Mantella, and Guibemantis), while the second comprises karyotypes with one or more uniarmed elements (Gephyromantis, Mantidactylus, and Microhylidae). The localization of NORs follows a diverse pattern, often varying even among closely related species. Heterochromatin distribution and composition also appear to be species-specific and thus taxonomically informative. Beyond summarizing existing knowledge, this work establishes a unified framework for interpreting chromosome evolution within the unique biogeography and evolutionary history of Madagascar. Our synthesis provides essential baseline data for future molecular, genomic, and conservation studies, thereby enhancing our understanding of the mechanisms that have generated and maintained the island's extraordinary amphibian diversity.

In addition to their historical relevance, underwater sites of cultural heritage (e.g., shipwrecks, archeological sites) represent secondary habitats for marine life. However, despite a growing interest in their ecological role, studies focusing on these artificial environments remain limited. In this study, we performed the first systematic assessment of the marine biodiversity associated with the submerged structures of the ancient roman port of Egnazia. In particular, we conducted a seasonal (summer 2022 and winter 2023) comparative analysis of the qualitative and quantitative variations in the observed nektonic and benthic taxa between the submerged piers and two surrounding control areas. For benthopelagic and vagile benthic taxa, two seasonal samplings with four transects (of 10 m × 4 m) and three replicates per transect were conducted to analyze taxon diversity, abundance, and variability of individual size. The photo-quadrat method was employed to characterize sessile benthic taxa, using PVC frames measuring 40 cm × 40 cm, randomly placed on the study substrates with 20 replicates for each pier and the two controls. Our results highlight the occurrence of 75 taxa (67 associated with the submerged piers and 63 with the surrounding control areas), including 17 benthopelagic species, 26 vagile benthic and 32 sessile benthic taxa. Overall, our findings highlight that the submerged ancient structures of Egnazia represent a stable and functional marine habitat, promoting an increase in the local biodiversity and abundance of individuals of different species.

We present a comparative chromosome study of several taxa of the Malagasy ground geckos of the Paroedura bastardi and P. picta species groups. We employed a preliminary molecular analysis using a trait of the mitochondrial 16S rRNA gene (of about 570 bp) to assess the taxonomic status of the samples studied and a cytogenetic analysis with standard karyotyping (5% Giemsa solution), silver staining (Ag–NOR staining) and sequential C-banding (C-banding + Giemsa and + fluorochromes). Our results show that all the taxa studied of the P. bastardi group (P. ibityensis, P. rennerae and P. cf. guibeae) have a similar karyotype composed of 2n = 34 chromosomes, with two metacentric pairs (1 and 3) and all other pairs being acrocentric. Chromosome diversification in the P. bastardi group was mainly linked to the diversification of heteromorphic sex chromosome systems (ZZ/ZW) in P. ibityensis and P. rennerae, while no heteromorphic sex chromosome pair was found in P. cf. guibeae. The two taxa investigated of the P. picta species group (here named P. picta and P. cf. picta based on molecular data) showed the same chromosome number of 2n = 36, mostly acrocentric elements, but differed in the number of metacentric elements, probably as a result of an inversion at chromosome pair 2. We highlight that the genus Paroedura is characterized by the independent diversification of heterogametic sex chromosomes in different evolutionary lineages and, similarly to other phylogenetically related gecko genera, by a progressive formation of a biarmed element by means of tandem fusions and inversions of distinct pairs.

Unlike many other fungicides, strobilurins are applied several times during the growing season for prophylactic purposes, thus heightening the risk of environmental contamination. In the EU, the dimoxystrobin approval period lasted for 17 years. It has been classified as moderately toxic to birds and highly toxic to earthworms, and it is suspected to be carcinogenic to humans. However, it is still commercialized in several countries. The effects of dimoxystrobin are still largely underexplored, with only three studies reporting sublethal alterations in fish. Here, we evaluated for the first time the effects of dimoxystrobin on zebrafish liver after short-term exposure (96 h) to two sublethal and environmentally relevant concentrations (6.56 and 13.13 μg/L), providing evidence of morphological, functional, and ultrastructural modifications. We revealed severe alterations encompassing three reaction patterns: circulatory disturbance, regressive and progressive changes, which also showed a dose-dependent trend. Furthermore, we revealed that dimoxystrobin induced a significant increase in lipid content, a decrease in glycogen granules and affected the defensive response against oxidative stress through a significant downregulation of SOD and CAT. The information presented here demonstrates that the hazardous properties of dimoxystrobin may result from several pathological events involving multiple targets. Our results also emphasize the importance of the combined use of morphological, ultrastructural and functional investigation in ecotoxicological studies.

Limited data are available about the coastal ecology of the Calabria region, in the southern Italy. As well, data about the levels of biodiversity and the structure of food webs in these environments are totally missing. However, considering the wide range of physical and ecological conditions distinguishing these ecosystems, a remarkable spread of biodiversity is expected. This review represents a first attempt to describe and estimate the structure of the food webs in a range of shallow stations along the south-western coasts of southern Italy, in the Ionian Sea. They comprise a Special Area of Conservation (Amendolara shoal), an urbanized area (Sibari), a sandy area impacted by industrial installations (Corigliano) and a seagrass meadow (Calopezzati). For each of these stations, we produced ecological simulation models based on the available information in order to estimate the structure of food webs. In particular, the patterns of distribution of trophic resources resulting from literature data were statistically compared to a theoretical model based on the physical and ecological features of coastal ecosystems. The model was responsive and predicted remarkable differences in the compartmentalization of trophic resources among stations, due to the diversity of substrates and the anthropic activities impacting each area. Large availability of resources for omnivores and detritivores characterized most stations. A noteworthy richness of trophic resources for herbivores was forecasted off Amendolara and Calopezzati. In parallel, the model obtained for the urbanized area of Sibari predicted a higher abundance of trophic resources for filter feeders, especially in the deepest station.

Karyotype diversification represents an important, yet poorly understood, driver of evolution. Squamate reptiles are characterized by a high taxonomic diversity which is reflected at the karyotype level in terms of general structure, chromosome number and morphology, and insurgence of differentiated simple or multiple-sex-chromosome systems with either male or female heterogamety. The potential of squamate reptiles as unique model organisms in evolutionary cytogenetics has been recognised in recent years in several studies, which have provided novel insights into the chromosome evolutionary dynamics of different taxonomic groups. Here, we review and summarize the resulting complex, but promising, general picture from a systematic perspective, mapping some of the main squamate karyological characteristics onto their phylogenetic relationships. We highlight how all the major categories of balanced chromosome rearrangements contributed to the karyotype evolution in different taxonomic groups. We show that distinct karyotype evolutionary trends may occur, and coexist, with different frequencies in different clades. Finally, in light of the known squamate chromosome diversity and recent research advances, we discuss traditional and novel hypotheses on karyotype evolution and propose a scenario of circular karyotype evolution.

Compound eyes undoubtedly represent the widespread eye architecture in the animal kingdom. The insects' compound eye shows a wide variety of designs, and insects use their visual capacity to accomplish several tasks, including avoiding enemies, searching for food and shelter, locating a mate, and acquiring information about the environment and its surroundings. Broad literature data support the concept that visual ability lies in the way the eyes are built. Since the resolution and sensitivity of the compound eye are partly determined by the density of the ommatidia and the size of the facets. Morphological parameters of the compound eyes could influence the function of the visual organ and its capacity to process information, also representing a sensitive indicator of different habitat demands. In this study, we compared compound eyes' parameters in four closely related species of tiger beetles to disclose differences arising from different habitats. Furthermore, to investigate whether there are consistent intersexual differences, we also compared the most relevant parameters of the eye in males and females of four selected species. Our results show sex-related and interspecific differences that occur in examined species.

Strobilurins, among the most used fungicides worldwide, are considered non-toxic to mammals and birds, but there is growing evidence that these compounds are highly toxic to aquatic species. Dimoxystrobin has been included in the 3rd Watch List of the European Commission, and it has been classified as very toxic to aquatic life. However, previous studies focused on acute toxicity and only two reports are available on its impact on fish, and none on its effects during the early life stages. Here, we evaluated for the first time the effects induced on zebrafish embryos and larvae by two dimoxystrobin sublethal concentrations (6.56 and 13.13 μg/L) falling in the range of predicted environmental concentrations. We demonstrated that short-term exposure to dimoxystrobin may exert adverse effects on multiple targets, inducing severe morphological alterations. Moreover, we showed enhanced mRNA levels of genes related to the mitochondrial respiratory chain and ATP production. Impairment of the swim bladder inflation has also been recorded, which may be related to the observed swimming performance alterations.

In this work, we performed a preliminary molecular analysis and a comparative cytogenetic study on 5 different species of Malagasy chameleons of the genus Brookesia (B. superciliaris) and Furcifer (F. balteautus, F. petteri, F. major and F. minor). A DNA barcoding analysis was first carried out on the study samples using a fragment of the mitochondrial gene coding for the cytochrome oxidase subunit 1 (COI) in order to assess the taxonomic identity of the available biological material. Subsequently, we performed on the studied individuals a chromosome analysis with standard karyotyping (5% Giemsa solution at pH 7) and sequential C-banding + Giemsa, + CMA3, and + DAPI. The results obtained indicate that the studied species are characterized by a different chromosome number and a variable heterochromatin content and distribution, with or without differentiated sex chromosomes. In particular, B. superciliaris (2n = 36) and F. balteatus (2n = 34) showed a similar karyotype with 6 macro- and 12–11 microchromosome pairs, without differentiated sex chromosomes. In turn, F. petteri, F. major, and F. minor showed a karyotype with a reduced chromosome number (2n = 22–24) and a differentiated sex chromosome system with female heterogamety (ZZ/ZW). Adding our newly generated data to those available from the literature, we highlight that the remarkable chromosomal diversification of the genus Furcifer was likely driven by non-homologous chromosome fusions, including autosome–autosome, Z–autosome, and W–autosome fusions. The results of this process resulted in a progressive reduction in the chromosome number and partially homologous sex chromosomes of different shapes and sizes.

BACKGROUND:The receptor for advanced glycation-end products (RAGE) and its ligands have been implicated in obesity and associated inflammatory processes as well as in metabolic alterations like diabetes. In addition, RAGE-mediated signaling has been reported to contribute to the metastatic progression of breast cancer (BC), although mechanistic insights are still required. Here, we provide novel findings regarding the transcriptomic landscape and the molecular events through which RAGE may prompt aggressive features in estrogen receptor (ER)-positive BC.METHODS:MCF7 and T47D BC cells stably overexpressing human RAGE were used as a model system to evaluate important changes like cell protrusions, migration, invasion and colony formation both in vitro through scanning electron microscopy, clonogenic, migration and invasion assays and in vivo through zebrafish xenografts experiments. The whole transcriptome of RAGE-overexpressing BC cells was screened by high-throughput RNA sequencing. Thereafter, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses allowed the prediction of potential functions of differentially expressed genes (DEGs). Flow cytometry, real time-PCR, chromatin immunoprecipitation, immunofluorescence and western blot assays were performed to investigate the molecular network involved in the regulation of a novel RAGE target gene namely EphA3. The clinical significance of EphA3 was explored in the TCGA cohort of patients through the survivALL package, whereas the pro-migratory role of EphA3 signaling was ascertained in both BC cells and cancer-associated fibroblasts (CAFs). Statistical analysis was performed by t-tests.RESULTS:RNA-seq findings and GSEA analysis revealed that RAGE overexpression leads to a motility-related gene signature in ER-positive BC cells. Accordingly, we found that RAGE-overexpressing BC cells exhibit long filopodia-like membrane protrusions as well as an enhanced dissemination potential, as determined by the diverse experimental assays. Mechanistically, we established for the first time that EphA3 signaling may act as a physical mediator of BC cells and CAFs motility through both homotypic and heterotypic interactions.CONCLUSIONS:Our data demonstrate that RAGE up-regulation leads to migratory ability in ER-positive BC cells. Noteworthy, our findings suggest that EphA3 may be considered as a novel RAGE target gene facilitating BC invasion and scattering from the primary tumor mass. Overall, the current results may provide useful insights for more comprehensive therapeutic approaches in BC, particularly in obese and diabetic patients that are characterized by high RAGE levels.

Strobilurins represent the most widely used class of fungicides nowadays andare considered relatively non-toxic to mammals and birds but highly toxic to aquatic biota. Dimoxystrobin is one of the novel strobilurins, recently included in the 3rd Watch List of the European Commission as available data indicate that it could pose a significant risk to aquatic species. As yet, the number of studies explicitly assessing the impact of this fungicide on terrestrial and aquatic species is extremely low, and the toxic effects of dimoxystrobin on fish have not been reported. Here we investigate for the first time the alterations induced by two environmentally relevant and very low concentrations of dimoxystrobin (6.56 and 13.13 μg/L) in the fish gills. morphological, morphometric, ultrastructural, and functional alterations have been evaluated using zebrafish as a model species. We demonstrated that even short-term exposure (96 h) to dimoxystrobin alters fish gills reducing the surface available for gas exchange and inducing severe alterations encompassing three reaction patterns: circulatory disturbance and both regressive and progressive changes. Furthermore, we revealed that this fungicide impairs the expression of key enzymes involved in osmotic and acid-base regulation (Na+/K+-ATPase and AQP3) and the defensive response against oxidative stress (SOD and CAT). The information presented here highlights the importance of combining data from different analytical methods for evaluating the toxic potential of currently used and new agrochemical compounds. Our results will also contribute to the discussion on the suitability of mandatory ecotoxicological tests on vertebrates before the introduction on the market of new compounds.