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Mass extinctions are major influences on both the phylogenetic structure of the modern biota and our ability to reconstruct broad-based patterns of evolutionary history. The most recent mass extinction is also the most famous—that which implicates a bolide impact in defining the Cretaceous/Palaeogene boundary (K/Pg). Although the biotic effects of this event receive intensive scrutiny, certain ecologically important and diverse groups remain woefully understudied. One such group is the freshwater ray-finned fishes (Actinopterygii). These fish represent 25% of modern vertebrate diversity, yet the isolated and fragmentary nature of their K/Pg fossil record limits our understanding of their diversity dynamics across this event. Here, we address this problem using diversification analysis of molecular-based phylogenies alongside a morphotype analysis of fossils recovered from a unique site in the Denver Basin of western North America that provides unprecedented K/Pg resolution. Our results reveal previously unrecognized signals of post-K/Pg diversification in freshwater clades and suggest that the change was driven by localized and sporadic patterns of extinction. Supported inferences regarding the effects of the K/Pg event on freshwater fish also inform our expectations of how freshwater faunas might recover from the current biodiversity crisis. [ABSTRACT FROM AUTHOR]

By comparing the morphological variability of two groups of pycnodonts, the Coccodontoidea and the Nursalliini, the author demonstrates that in the Late Cretaceous these two groups had adopted completely different blauplans. Throughout the Cretaceous and the Eocene, the Nursalliini maintained the typical shape of the pycnodonts, rounded and flattened. The Cocodontoidea expressed 21 new species that belonged to 17 new genera, across which there was extraordinary biodiversity. The typical body plan was almost abandoned, and elongated, and somewhat very tapered, forms emerged (Stenoprotome), which lived alongside very short and very high fish. Indeed, this period produced the shortest and the highest fish that have ever lived (Maraldichthys). Indeed, while the more highly variable groups (Coccodontoidea) represented a punctiform episode in the evolutionary history of pycnodonts, remaining confined to the arm of Tethys (central Lebanon) and to the time period corresponding to the lower upper Cenomanian, the morphologically more conservative groups (Nursalliini) colonised the seas of the entire planet from the Cretaceous to the Eocene, even surviving the great mass extinction period corresponding to the Mesozoic-Cenozoic passage. Thus, the enormous biodiversity of Coccodointoidea did not represent a selective advantage over the environmental crisis at the end of the Cretaceous. [ABSTRACT FROM AUTHOR]

The viviparous eelpout Zoarces viviparus is a common fish across the North Atlantic and has successfully colonized habitats across environmental gradients. Due to its wide distribution and predictable phenotypic responses to pollution, Z. viviparus is used as an ideal marine bioindicator organism and has been routinely sampled over decades by several countries to monitor marine environmental health. Additionally, this species is a promising model to study adaptive processes related to environmental change, specifically global warming. Here, we report the chromosome-level genome assembly of Z. viviparus , which has a size of 663 Mb and consists of 607 scaffolds (N50 = 26 Mb). The 24 largest represent the 24 chromosomes of the haploid Z. viviparus genome, which harbors 98% of the complete Benchmarking Universal Single-Copy Orthologues defined for ray-finned fish, indicating that the assembly is highly contiguous and complete. Comparative analyses between the Z. viviparus assembly and the chromosome-level genomes of two other eelpout species revealed a high synteny, but also an accumulation of repetitive elements in the Z. viviparus genome. Our reference genome will be an important resource enabling future in-depth genomic analyses of the effects of environmental change on this important bioindicator species. [ABSTRACT FROM AUTHOR]

The vertebral column is a characteristic structure of vertebrates. Genetic studies in mice have shown that Hox-mediated patterning plays a key role in specifying discrete anatomical regions of the vertebral column. Expression pattern analyses in several vertebrate embryos have provided correlative evidence that the anterior boundaries of Hox expression coincide with distinct anatomical vertebrae. However, because functional analyses have been limited to mice, it remains unclear which Hox genes actually function in vertebral patterning in other vertebrates. In this study, various zebrafish Hox mutants were generated for loss-of-function phenotypic analysis to functionally decipher the Hox code responsible for the zebrafish anterior vertebrae between the occipital and thoracic vertebrae. We found that Hox genes in HoxB- and HoxC-related clusters participate in regulating the morphology of the zebrafish anterior vertebrae. In addition, medaka hoxc6a was found to be responsible for anterior vertebral identity, as in zebrafish. Based on phenotypic similarities with Hoxc6 knockout mice, our results suggest that the Hox patterning system, including at least Hoxc6, may have been functionally established in the vertebral patterning of the common ancestor of ray-finned and lobe-finned fishes. [ABSTRACT FROM AUTHOR]

Aim Location Time Period Major Taxa Studied Methods Results Main Conclusions The relationship between body size and trophic position (BS–TP) typically exhibits a positive correlation in aquatic foodwebs, but the strength of this relationship is contingent on ecosystem type and climate. Different hypotheses have been proposed to elucidate climate and ecosystem type effects on the BS–TP relationship for ray‐finned fish. However, our understanding of whether such a relationship evolved in a correlated fashion, spanning various climates and ecosystem types, remains limited.Temperate and tropical marine and freshwater ecosystems.Present to millions of years ago.Ray‐finned fish.We used a phylogenetic tree and TP and BS data of more than a thousand freshwater and marine ray‐finned fishes, from distinct climates and ecosystems, to investigate patterns on macroevolutionary time scales of the evolutionary correlation of BS and TP. As part of our investigation, we also ran analyses excluding herbivores and detritivores from the dataset, then further focusing solely on carnivores.We found distinct patterns of the BS–TP evolutionary correlation for different climates and ecosystems. The evolutionary correlation between BS and TP was significant for all ecosystem type–climate combinations, except for tropical freshwater ecosystems. The results remained consistent even after accounting for phylogenetic uncertainty and when excluding herbivores and detritivores from the analysis.We found a weaker evolutionary correlation between BS and TP in tropical freshwater ecosystems. These findings are consistent with the stronger BS–TP relationship between extant taxa in temperate climates compared to the tropics, illustrating how evolutionary dynamics might have influenced the trophic structure of fish and contributed to shaping macroecological patterns of the BS–TP relationship. Our findings suggest that limitations that hinder evolutionary integration between BS and TP might be primarily attributed to energetic constraints imposed by temperature and the availability of C‐rich food resources at the base of the foodweb. [ABSTRACT FROM AUTHOR]

The present drainage network of Bulgaria is the result of a complex Neogene and Quaternary evolution. Karst, which has developed on 23% of the territory, further complicates the hydrological pattern. Fresh waters of Bulgaria drain into the Black Sea and the Aegean Sea basins and can be roughly divided into the Danube (Middle and Lower Danube), non‐Danube Black Sea, East Aegean, and West Aegean hydrological regions. Phoxinus, a small leuciscid fish, has a mosaic distribution in all four of these regions, inhabiting small mountainous and semi‐mountainous streams. Based on morphology, it was identified as three species, Phoxinus phoxinus in the Danube, Phoxinus strandjae in the non‐Danube, and Phoxinus strymonicus in West Aegean region. Later, molecular data revealed Phoxinus csikii and Phoxinus lumaireul in the Middle Danube and P. csikii in the Lower Danube. Phoxinus has been the focus of many studies, showing a high molecular and morphological diversity, which is not entirely consistent with previous morphology‐only‐based taxonomic concepts. In this study, molecular (a mitochondrial marker and a nuclear marker) and morphological data from both historical and recently sampled collections were analysed to assess the applicability of the integrative approach in Phoxinus. The results showed a significant influence of the complex paleo‐ and recent hydrology on the currently observed genetic structure of the considered populations and species. Furthermore, the study also demonstrated a strong influence of phenotypic plasticity on the morphological analysis of Phoxinus and the lack of a clear differentiation between P. csikii and P. strandjae. A barcoded specimen was designated as neotype to fix the species named P. strandjae in the current taxonomic concept. Finally, a significant discordance between genetically delimited clades and phenotypic groups did not allow a proper delineation of the species distributed in Bulgaria, demonstrating that more molecular markers are needed for further taxonomic study of the Phoxinus complex. [ABSTRACT FROM AUTHOR]

Secondary sexual dimorphism is an interesting and stupendous subject of research study due to the fact that it is a result of sexual selection, mostly attributed to either female mate choice or male-male competition. This study aims to investigate the microscopic characterization of scales and fin rays in several aphaniids (Cyprinodontiformes: Aphaniidae) to find out the possibility of using these structures as secondary sexual dimorphism traits and discuss their taxonomic and evolutionary significance. Herein, the results reveal that (i) male individuals of aphaniid species of the genera Aphanius, Aphaniops and Paraphanius present contact organs in the forms of ctenus-like structure (in posterior margin of the scales) and spicule-like structure (in anal fin rays) that show sexual dimorphism of scales and fins; (ii) number, position, size and shape of contact organs provide taxonomic signal to distinguish members of the genus Aphaniops from two other genera; (iii) females of Aphaniops ginaonis also represent contact organs in scales but fewer than males and (iv) as the sexual dimorphism results from different sexual selection pressures acting on males and females, it provides evolutionary signals. [ABSTRACT FROM AUTHOR]

The Albian Muhi Quarry of Central Mexico has produced a variety of fishes, among which the teleosts are the most diversified, including representatives of stem groups together with a variety of crown groups. A new genus and species, †Xeneichthys yanesi, is described based on a unique combination of characters, such as a dorsoventral elongation and narrowing of infraorbitals 2 and 3, preopercle, opercle, and cleithrum; absence of some bones, such as the infraorbital 5, interopercle, and pelvic plate and fin; presence of an elongated urostyle and a membranous outgrowth or stegural on the first uroneural; and cycloid and ctenoid scales on the flanks. Due to its combination of characters, †Xeneichthys yanesi is interpreted as belonging to a new extinct family, †Xeneichthyidae, which is considered as an Euteleostei or Euteleosteomorpha incertae sedis. The fish faunas of another Albian quarry, Tlayúa of Tepexi de Rodriguez, Puebla, and Muhi Quarry are compared, and although both contain taxa that can be assigned to stem teleosts (e.g., †ichthyodectiforms and †crossognathiforms), both also contain crown teleosts (e.g., elopomorphs, clupeomorphs, and euteleosts)—all of which are endemic to their respective quarries and make them important centers of diversification of fish faunas during the Early Cretaceous. [ABSTRACT FROM AUTHOR]

Ginglymodians (e.g. gars) are a group of holostean fishes with a rich fossil history in the Mesozoic. The resolution of interrelationships among extinct ginglymodians is central to the problem of understanding the origin of this clade. Here, a new fossil ginglymodian, Diandongichthys ocellatus gen. et sp. nov. is described based on 13 well-preserved specimens from the Early-Middle Triassic (Anisian) marine deposits exposed in Luoping, eastern Yunnan, China. The discovery documents one of the oldest and smallest ginglymodians hitherto known from the Middle Triassic, with a maximum standard length of 41 mm. Diandongichthys , although displaying several synapomorphies of ginglymodians, retains some primitive states with respect to other early ginglymodians (e.g. a short snout without anterior infraorbitals, a maxilla ending below the orbit, and a median gular); consequently, it is nested at the base of the Ginglymodi in this phylogenetic study. Besides body shape, some autapomorphies on the cranial bones and caudal fin easily distinguish Diandongichthys from other members of this clade. The discovery provides new insights into the origin and early diversification of ginglymodian fishes. [ABSTRACT FROM AUTHOR]

The 47 vertebrate type specimens held in the University of Otago Geology Department are catalogued in detail. A short history of the collection is followed by lists of the type specimens under the Classes Actinopterygii, Reptilia, Aves and Mammalia. A fish trace-fossil is included at the end of the Actinopterygii. Where appropriate, the name changes of the genus or species are given in chronological order. The specimens are briefly described, locality and geological age information is provided. [ABSTRACT FROM AUTHOR]

Vertebrate fossils from Aotearoa New Zealand have revealed the global significance of Zealandia on the origins of modern birds, the history of cetaceans during major climatic events of the Cenozoic and the evolution of cartilaginous and ray-finned fish. Internationally important collections of vertebrate fossils are housed in collections across Aotearoa and have attracted researchers from around the world studying evolution, biogeography and climate change. This special issue of the Journal of the Royal Society of New Zealand celebrates the vertebrate fossils of Aotearoa by showcasing taonga (treasures) that are significant to global and local vertebrate history. [ABSTRACT FROM AUTHOR]

New genus and species of eurynotoidiid actinopterygians (Eurynotoidiformes), Kluchevichthys praeclarus gen. et sp. nov., is described from the uppermost Urzhumian (Kluchevskoy Ovrag locality), Tetushi District, Republic of Tatarstan. The holotype of а new form is an almost complete, non-deformed skeleton. The diagnostic characters of K. praeclarus were obtained in the morphology of the skull roof bones, dental system, scales and fins. The morphology of the marginal dentition, combining the tricuspid pattern of tooth crowns with the conical shape of all their apices allows positioning of a new taxon at the base of most phylogenetic branches of herbivorous Eurynotoidiformes having more specialized condition of the dental system, which corresponds well to stratigraphic data.

The abundance of shark and actinopterygian fossils in the Cretaceous and Paleogene strata of the Atlantic Coastal Plain is well documented; but much remains unknown about the survivorship patterns of these major components of shallow marine faunas in the western Atlantic through the K/Pg mass extinction. To shed light on this subject, we describe an assemblage of new actinopterygian, chondrichthyan, and reptilian microfossils recently recovered from the Maastrichtian Navesink and Maastrichtian–Danian Hornerstown formations at the Jean and Ric Edelman Fossil Park at Rowan University in Mantua Township, New Jersey. The new microfossils clarify extinction patterns across the K/Pg, create temporal and geographic range extensions for several taxa, and expand the known fauna of this regionally-rare and important K/Pg-boundary locality. We report 11 new additions to the vertebrate fauna of Edelman Fossil Park, the first Paleocene record of Saurocephalus lanciformis, the first Cretaceous records of Paralbula marylandica and Palaeogaleus vincenti, and the first recovery of gar and dercetid fish remains from the Paleocene in New Jersey (the last indicating that these fish survived the K/Pg extinction in the western Atlantic). Geographic range extensions include: Notidanodon brotzeni into the Western Hemisphere, Saurocephalus into northeastern North America and Phyllodus paulkatoi to the eastern coast of North America. A dentary of a juvenile alligatorid, Bottosaurus harlani, indicate that the mandible exhibited isometric growth through ontogeny. Our findings generally agree with other studies that these groups were significantly impacted by the extinction event, that extinctions were selective, and recovery was slow. This wealth of novel insights garnered from microfossils in this study highlights their critical importance for elaborating past faunas and illuminating the character of ancient ecosystems. We therefore recommend microsieving as a fruitful method for future faunal studies of shallow-marine strata and predict that such efforts will frequently yield similar important insights.

Abstract Around the middle of the nineteenth century, Italian palaeontologists began to investigate fossils of fishes and reptiles from the Middle Triassic outcrops in the vicinity of Monte San Giorgio (Canton Ticino, Switzerland). In 1924, researchers from the University of Zurich started their scientific excavations on the Swiss side. The many fish fossils found since then have often stood in the shadow of the more spectacular and mostly larger fossils of various aquatic reptiles. Beginning around 1980 the fish fossils in the collection of the Palaeontological Institute and Museum of Zurich University have subsequently been brought out of this shadow. The picture presently emerging is that of a species rich fish fauna located in six different fossiliferous beds of Anisian and Ladinian age with a few chondrichthyan, some coelacanth and a wealth of different actinopterygian taxa, many of them well preserved. The ongoing work not only results in taxonomic and systematic novelties, but gives also new insights into their palaeobiology, palaeoecology and palaeobiogeography.

The new snailfish Careproctus io is described on the basis of three specimens collected from the western North Pacific, off northeastern Honshu Island, Japan. The new species can be distinguished from congeners by the following characters: vertebrae 40–42; dorsal-fin rays 36 or 37; anal-fin rays 30; pectoral fin deeply notched with 28 or 29 rays, lower lobe reaching to anal-fin origin; large pelvic disk 34.2%–34.5% HL (10.3%–10.9% SL); teeth strongly trilobed on both jaws, inner teeth weakly trilobed or shouldered; cephalic pore pattern 2-6-7-2, chin pores paired; gill slit above pectoral-fin base; body bright red, non-variegated in life. Species of Careproctus Krøyer, 1862 typically have fewer pectoral-fin rays than anal-fin rays, although some recently-described species, including the present new species, have similar ray counts in both fins. The relationships between such counts, as well as pelvic disk size, are investigated for various snailfish, genera, and the generic limits of Careproctus discussed.

Citizen-collected data are used to describe ecological patterns and to obtain information about the distribution and trends of fauna and flora to inform management and conservation actions worldwide. However, considering the logistical and financial aspects, data should be collected in a cost-effective way. In addition, informed by the spatio-temporal distribution of observations, under-, and oversampled areas can be identified to guide future sampling efforts. Here, we classify 37,161 observations of South American Actinopterygii submitted to iNaturalist, occurring in both coastal and inland water bodies. We consider the status of the fish (live/dead), the characteristics (taxonomy and habitat) of the species and the circumstances of the observation (e.g., during fishing or diving). We test whether adding opportunistic observations increases species diversity, i.e., if observations of dead fish and fishing-related data add information to traditionally collected occurrence data (i.e. those of live fish observed during diving). Our dataset contained 2,377 species of 206 families, representing 24% of all South American ray-finned fish species. Dead individuals and observations related to fishing on average contributed 37% and 33% of annual observed species richness, respectively and added 151 unique species not recorded live or under circumstances not related to fishing. We found that for dead fish the rate of validation by peers and experts on the platform had been 20% lower compared to that of live individuals. We argue that recording organisms observed under different circumstances and in different conditions improves our knowledge of biodiversity. Demonstrating the value of all observations can encourage volunteers to make their data collection more inclusive. [ABSTRACT FROM AUTHOR]

The Actinopterygian and specifically the Teleostean peroxisome proliferator-activated receptors (PPARs) present an impressive variability and complexity in their structures, both at the gene and protein levels. These structural differences may also reflect functional divergence from their mammalian homologs, or even between fish species. This review, taking advantage of the data generated from the whole-genome sequencing of several fish species, highlights the differences in the primary structure of the receptors, while discussing results from the literature pertaining to the functions of fish PPARs and their activation by natural and synthetic compounds. [ABSTRACT FROM AUTHOR]

Solute carrier family 26 (Slc26) is a family of anion exchangers with 11 members in mammals (named Slc26a1‐a11). Here, we identified a novel member of the slc26 family, slc26a12, located in tandem with slc26a2 in the genomes of several vertebrate lineages. BLAST and synteny analyses of various jawed vertebrate genome databases revealed that slc26a12 is present in coelacanths, amphibians, reptiles, and birds but not in cartilaginous fishes, lungfish, mammals, or ray‐finned fishes. In some avian and reptilian lineages such as owls, penguins, egrets, and ducks, and most turtles examined, slc26a12 was lost or pseudogenized. Phylogenetic analysis showed that Slc26a12 formed an independent branch with the other Slc26 members and Slc26a12, Slc26a1 and Slc26a2 formed a single branch, suggesting that these three members formed a subfamily in Slc26. In jawless fish, hagfish have two genes homologous to slc26a2 and slc26a12, whereas lamprey has a single gene homologous to slc26a2. African clawed frogs express slc26a12 in larval gills, skin, and fins. These results show that slc26a12 was present at least before the separation of lobe‐finned fish and tetrapods; the name slc26a12 is appropriate because the gene duplication occurred in the distant past. [ABSTRACT FROM AUTHOR]

Ray-finned fishes, which compose nearly half of living vertebrate diversity, provide an excellent system for studying the evolution of novel body forms. Lampriformes is a species-poor lineage of acanthomorph ray-finned fishes that has evolved two very different and highly specialized body plans suited to life in pelagic oceanic habitats: the deep, round-bodied bathysomes and the ribbon-like taeniosomes. Here, we present a new phylogenetic hypothesis and divergence time estimates for lampriform fishes based on an updated morphological dataset and DNA sequences from nuclear genes for all but one of the living lampriform families and 55% of recognized extant genera. Our analyses resolve two major clades in Lampriformes: the Bathysomi and the Taeniosomi. A time calibrated phylogeny shows that the origin of living lampriforms coincides with the aftermath of the Cretaceous–Palaeogene extinction and that anatomically modern pelagic morphotypes evolved 10 Myr after the start of the Palaeogene. [ABSTRACT FROM AUTHOR]

Most tooth‐bearing non‐mammalian vertebrates have the capacity to replace their teeth throughout life. This capacity was lost in mammals, which replace their teeth only once at most. Not surprisingly, continuous tooth replacement has attracted much attention. Classical morphological studies (e.g. to analyse patterns of replacement) are now being complemented by molecular studies that investigate the expression of genes involved in tooth formation. This review focuses on ray‐finned fish (actinopterygians), which have teeth often distributed throughout the mouth and pharynx, and more specifically on teleost fish, the largest group of extant vertebrates. First we highlight the diversity in tooth distribution and in tooth replacement patterns. Replacement tooth formation can start from a distinct (usually discontinuous and transient) dental lamina, but also in the absence of a successional lamina, e.g. from the surface epithelium of the oropharynx or from the outer dental epithelium of a predecessor tooth. The relationship of a replacement tooth to its predecessor is closely related to whether replacement is the result of a prepattern or occurs on demand. As replacement teeth do not necessarily have the same molecular signature as first‐generation teeth, the question of the actual trigger for tooth replacement is discussed. Much emphasis has been laid in the past on the potential role of epithelial stem cells in initiating tooth replacement. The outcome of such studies has been equivocal, possibly related to the taxa investigated, and the permanent or transient nature of the dental lamina. Alternatively, replacement may result from local proliferation of undifferentiated progenitors, stimulated by hitherto unknown, perhaps mesenchymal, factors. So far, the role of the neurovascular link in continuous tooth replacement has been poorly investigated, despite the presence of a rich vascularisation surrounding actinopterygian (as well as chondrichthyan) teeth and despite a complete arrest of tooth replacement after nerve resection. Lastly, tooth replacement is possibly co‐opted as a process to expand the number of teeth in a dentition ontogenetically whilst conserving features of the primary dentition. That neither a dental lamina, nor stem cells appear to be required for tooth replacement places teleosts in an advantageous position as models for tooth regeneration in humans, where the dental lamina regresses and epithelial stem cells are considered lost. [ABSTRACT FROM AUTHOR]

Oxidative stress (OS) in aquatic organisms is associated with pressures within the marine environment by both anthropogenic and natural factors like pollution, climate change, ecological interactions, etc. These pressures can induce irreversible changes in the organism’s status and health influencing communities and ecosystems as well. Red mullet is a widely distributed and commercially important demersal fish species in the Black Sea. This makes it a promising bioindicator for the state of the marine environment and ecosystem health. This study aimed to investigate the effect of seasonal variations in the marine environment on OS in red mullet from four sites on the Bulgarian Black Sea coast – Kavarna, Kamchiya, St. Vlas and Sozopol. Most of the measured OS biomarkers displayed seasonal variations in the two studied fish organs – liver and gills. In autumn, higher lipid peroxidation levels and activities of superoxide dismutase (SOD), catalase (CAT), and glutathione-S-transferase (GST) were presented in the liver of fish from all studied sites. In gills, higher activity of SOD, CAT, GST, and acetylcholinesterase were measured in the summer. In conclusion, the significant local variability of the sea environment quality induced different levels of OS in autumn in the fish liver and in summer in the gills for all studied sites. The measured seasonal fluctuations in the red mullet’s OS biomarkers can be successfully used for biomonitoring and environmental marine risk assessment. [ABSTRACT FROM AUTHOR]

Two endemic Anatolian nemacheilids were studied cytogenetically for the first time. Diploid chromosome numbers, chromosome morphologies in the karyotypes and also C-band and Ag-NOR banding properties were recorded for the two species of Oxynoemacheilus. The diploid chromosome number is 50 and karyotypes contained 34 biarmed and 16 monoarmed chromosomes in Oxynoemacheilus axylos Yoğurtçuoğlu et al. 2022. In O. nasreddini Yoğurtçuoğlu et al. 2021, there are 30 biarmed and 20 monoarmed chromosomes. No heteromorphic sex chromosomes were determined. C-band patterns and the number of Ag-NORs were different between the two studied species. [ABSTRACT FROM AUTHOR]

Food availability influence the state of fish stocks, with effects on the demographics, composition and productivity of fish populations. In the spring seasons of 2018–2020, expeditions were carried out in order to collect data for Sprattus sprattus agglomerations, mesozooplankton community and S. sprattus stomach content analysis. Throughout the whole study period, it was shown that the fodder mesozooplankton component recorded high concentrations in the areas where fish had high catch values, promoting the best possible development of fish stocks. The analysis of S. sprattus stomach content highlighted the high consumption of copepods and meroplanktonic elements, with copepods being intensively consumed in 2019 and 2020. Fish productivity is directly associated with the presence or absence of mesozooplankton, which can have a cascading effect on fish stocks. [ABSTRACT FROM AUTHOR]

Background: Sciaenidae is one of the most important coastal fisheries in Taiwan, both in production and economic value. It is also significant as the main targetted diet of Chinese white dolphins, Sousa chinensis, especially for the genus Johnius, such as J. taiwanensis, J. belangerii and J. distinctus, which is primarily found in central-western Taiwan coastal waters. Despite an abundance of Johnius species occurrences reported in the Global Biodiversity Information Facility (GBIF) and the Taiwan Biodiversity Information Facility (TaiBIF) data portals (Mozambique, Australia, Taiwan, Korea, India, Indonesia, South Africa, Pakistan, Vietnam and China), there are no specific datasets that properly document the regional distribution of this genus, especially in Taiwanese waters. Thus, this paper describes a dataset of genus Johnius occurrences in waters on the central-western coast of Taiwan. The data collection for the present study was conducted from 2009 until 2020 and comprised 62 sampling events and 133 occurrence records. All fish specimens were collected by trawling in Miaoli, Changhwa and Yunlin Counties, Taiwan and brought back to the lab for identification, individual number count and body weight measurement. These processing data have been integrated and established in the Taiwan Fish Database and published in GBIF. This dataset contains six Johnius species and 2,566 specimens, making it comprehensive Johnius fish fauna and spatial distributional data on the coastal habitat in central-western Taiwanese waters. New information: This dataset contains 133 occurrence records of Johnius species (Sciaenidae) with 2,566 specimens, making it the most extensive public dataset of Johnius distribution records in Taiwan. The publication of this dataset through the TaiBIF and GBIF dataset platforms demonstrated that the number of Johnius spatial and temporal records in Taiwan waters is influenced by the topographical structure of the Changyun Rise (CYR) in combination with the cold current of the China Coastal currents and bound with the warm currents of the Kuroshio and the South China Sea on the central-western coast of Taiwan. The data serve as the foundation for understanding the biogeography and Johnius species ecology in Taiwan's coastal waters, which present a 2°C water temperature difference split at the CYR. [ABSTRACT FROM AUTHOR]

Subcritical water (SCW) hydrolysis was applied to valorize the low-valued ray-finned fish (Labeobarbus nedgia) into valuable protein hydrolysates, employing N2 and CO2 as pressurization agents at varying temperatures (140, 160, 180, and 200 °C). The degree of hydrolysis (DH) and total free amino acid content increased with temperature for both pressurizing agents. The highest DH (54.5 ± 0.4%) and total free amino acid content (210 ± 1 mg/gprot) were observed at 200 °C when CO2 gas was used as the pressurizing agent. Predominantly, glycine and alanine were released for both pressurizing agents. The antioxidant activity, evaluated through three different assays, increased with temperature and was found to be the highest at 200 °C. This study illustrated the advantages of the intensified SCW technology by using CO2 as a pressurization agent in valorizing low-valued ray-finned fish (Labeobarbus nedgia), as animal residue rich in proteins, for the production of valuable protein hydrolysates with a high fraction of valuable free amino acids, which could offer potential applications as a functional ingredient in the food industry. [ABSTRACT FROM AUTHOR]

Gonad development stages (GDS) are a critical tool that can be easily applied in fisheries to visually discriminate mature from immature organisms and assess their reproductive condition. This study proposes a morphochromatic scale to define gonad development stages for razor surgeonfish (Prionurus laticlavius) based on morphological and structural assessments of the gonad, histologically validated using multivariate dummy matrices modeled through multiple linear regression analyses. Gonads of 271 specimens were photographed prior to preservation to describe their shape, size, color, and turgor for morphochromatic analysis. Later, gonads were processed using standard histological methods. An oocyte growth scale was designed based on oocyte diameter and follicular wall thickness for each stage. In addition, five morphochromatic gonad development stages were histologically validated: immature, developing, spawning capable, regressing, and regenerating. Morphochromatic variations were observed in the last three stages in both sexes. Results show that gonad morphology and structure of P. laticlavius are similar to those of other acanthurids, albeit with some asymmetric and morphological differences, as well as gonad morphochromatic in both sexes. These findings confirm that maturation is species‐specific. Also, although not a critical character, gonad colouration was found to play a major role in distinguishing between gonad development stages along with shape, size, vascularity (females), and folds (males). Therefore, gonad colouration should not be entirely overlooked because doing so may lead to errors in determining sexual maturity stages. [ABSTRACT FROM AUTHOR]

Examination of the original descriptions and available type specimens of nominal species previously regarded as synonyms of Thrissina mystax (Bloch and Schneider, 1801), and many non‐type specimens representing an extensive geographic range, confirmed the validities of T. mystax, Thrissina porava (Bleeker, 1849), and Thrissina valenciennesi (Bleeker, 1866). Additionally, Engraulis poorawah Bleeker, 1872, a nominal species previously regarded as a junior synonym of T. mystax, is recognized as a junior synonym of Thrissina malabarica (Bloch, 1795). Diagnoses and detailed color descriptions are given for all of the valid species, in addition to clarification of their taxonomic histories, and neotype designation for T. porava. The phylogenetic relationships among 15 species of Thrissina (including T. porava and T. valenciennesi but not T. mystax) were reconstructed from the mitochondrial cytochrome oxidase I (COI) gene. T. porava and T. valenciennesi were not recovered as a monophyletic group, instead being divergent from each other and the other species of Thrissina by 12.4% and >11.7% mean uncorrected distances, respectively, confirming their reciprocal validity. [ABSTRACT FROM AUTHOR]

Evolutionary stasis characterizes lineages that seldom speciate and show little phenotypic change over long stretches of geological time. Although lineages that appear to exhibit evolutionary stasis are often called living fossils, no single mechanism is thought to be responsible for their slow rates of morphological evolution and low species diversity. Some analyses of molecular evolutionary rates in a handful of living fossil lineages have indicated that these clades exhibit slow rates of genomic change. Here, we investigate mechanisms of evolutionary stasis using a dataset of 1,105 exons for 481 vertebrate species. We demonstrate that two ancient clades of ray-finned fishes classically called living fossils, gars and sturgeons, exhibit the lowest rates of molecular substitution in protein-coding genes among all jawed vertebrates. Comparably low rates of evolution are observed at fourfold degenerate sites in gars and sturgeons, implying a mechanism of stasis decoupled from selection that we speculate is linked to a highly effective DNA repair apparatus. We show that two gar species last sharing common ancestry over 100 million years ago produce morphologically intermediate and fertile hybrids in the wild. This makes gars the oldest naturally hybridizing divergence among eukaryotes and supports a theoretical prediction that slow rates of nucleotide substitution across the genome slow the accumulation of genetic incompatibilities, enabling hybridization across deeply divergent lineages and slowing the rate of speciation over geological timescales. Our results help establish molecular stasis as a barrier to speciation and phenotypic innovation and provide a mechanism to explain the low species diversity in living fossil lineages. [ABSTRACT FROM AUTHOR]

Eurynotoidiformes are a little‐known group of actinopterygian fishes from the Permian of European Russia, characterized by the possession of multicuspid marginal teeth arranged in a single row. Morphologically, the teeth resemble those of Recent Cichlidae, Acanthuridae, Siganidae or Serrasalmidae, suggesting similar trophic adaptations related to herbivory. Tooth histology is similar to the majority of basal actinopterygians (composed of dentine, acrodin and collar enamel). Teeth are ankylosed in their attachment, and labial pleurodont in implantation, strengthening the tooth. The multicuspid tooth crowns derive from conical teeth of predatory or omnivorous ancestors, analogous to the evolution of multicuspid teeth in cichlid fishes. Tooth replacement in eurynotoidiforms is most comparable to an alternating pattern, with a possible simultaneous, unilateral replacement occurring in the whole jaw, similar to characiform fishes. Replacement teeth were formed extraosseously. Teeth of the inner dental arcade were conical. Based on comparisons with the teeth of extant actinopterygians specialized for herbivory, along with functional morphological analysis and consideration of wear patterns, we hypothesize that eurynotoidiforms represent the oldest known actinopterygians specialized for herbivory. Several strategies of herbivory in Recent actinopterygians were already realized by eurynotoidiforms as early as the Late Palaeozoic (middle and late Permian): grazing/cutting filamentous algae (Lapkosubia spp., Isadia suchonensis), browsing/biting off macrophyte fragments (Isadia aristoviensis), scraping/harvesting periphyton from hard substrates (Isadia opokiensis, I. arefievi). However, notable morphological differences in the jaws (elongate) and tooth arrangement (homodont along the jaw, functional teeth separated) suggest that this Permian experiment in herbivory followed different pathways compared to extant taxa. [ABSTRACT FROM AUTHOR]

The morphology of skin armament has long been studied in some of freshwater sculpins, but has not found wide use in the taxonomy of this group. To assess the taxonomic value and determine the patterns of variability of this character, alizarin-stained skin samples of 19 diadromous and freshwater sculpins from Eurasia and one ancient North American species, Leptocottus armatus , were examined for the morphology of prickles. Three morphological types of prickles were ascertained. The largest prickles with a wide basal plate having an uneven anterior edge and a short, strong spine should be considered as the ancestral state. On a series of prickles examined a successive process of reduction was revealed from the ancestral type to the prickles that represent a thin, elongated, fusiform spine extending from a barely visible rounded basal plate with a smooth anterior edge, usually specific for younger freshwater species. The types of skin armament are not strictly consistent with the current concepts on the phylogeny of the studied freshwater Cottidae in view of the phenotypic parallelisms in this group. It is tentatively indicated insignificant intraspecific variation of the prickles shape in Mesocottus haitej , Cottus amblystomopsis , C. czerskii , and C. volki. Identification of most species studied using a single prickle is quite a challenge, although some species are easily identified this way. The species-specificity of prickles is shown to be the greatest in deeply divergent lineages, providing the opportunity to use these structures for diagnosing species and revealing hidden species richness. The skin armament morphology may also become an accessible and useful tool for testing taxonomic, biogeographical, and evolutionary hypotheses. [ABSTRACT FROM AUTHOR]

This paper contains information on the records of bottom macroinvertebrates, fish, amphibians, reptiles, birds and mammals collected during a field expedition in the valley of the Shokhdara River (in the vicinity of Khorog) near its mouth and confluence with the Panj River in autumn 2019-- spring 2020. As a result of the study, 3 species of fish (Actinopterigii Cyprinidae -- 2, Nemacheilidae -- 1 were found in the Shokhdara River and 1 additional species was confirmed by local people. Five species of reptiles (Squamata, Colubridae -- 2, Viperidae -- 1, Agamidae -- 1, Gekkonidae -- 1) and 1 species of amphibians (Anura, Bufonidae -- 1) were recorded. Twenty-four taxa of aquatic macroinvertebrates were recorded (89.7 % -- Insecta): Simuliidae -- 35.8 %, Ephemeroptera -- 18.7 %, Chironomidae -- 18 %, Trichoptera -- 10.5 %, Oligochaeta -- 6.5 %, Plecoptera -- 2.8 %, Diptera -- 2.5 %, Gastropoda -- 2.5 %. Nematoda, Turbellaria, Ostracoda, Copepoda, Cyclops spp., Sphaerium spp., Araneida, Acarina, Odonata, Heteroptera, Coleoptera, Neuroptera, Lepidoptera and Megaloptera represented only 2.7 % of the collected specimens of bottom invertebrates. Ninety-nine bird species (48 % of the avifauna of the study area) were recorded during the autumn/spring surveys. Among mammals, rare and internationally protected species such as Asian otter, snow leopard and Himalayan brown bear were confirmed to inhabit the areas adjacent to the surveyed river valley. [ABSTRACT FROM AUTHOR]

The Persian Gulf is a semi-enclosed marginal sea with a subtropical climate in southern Iran. One of the most productive coastal habitats in this region is the mangrove forests which support rich biodiversity and play an essential role in sustainable fisheries. Because of the fish's dependence on this ecosystem as a nursery habitat and its vulnerability to various natural and anthropogenic stresses and disturbances, it seems critical to identify and classify the fish species in this region and screen biodiversity. A segment (593 bp) of the cytochrome oxidase subunit I (COI) gene was used to identify the fish in the largest mangrove area of the Persian Gulf. In the present study, we created a comprehensive fish barcoding database for 53 species belonging to 39 genera, 32 families, and 17 orders. For six species, novel DNA barcodes to the global gene databases of GenBank and BOLD were introduced (Ilisha megaloptera, Pseudosynanceia melanostigma, Sillago sp., Hyporhamphus sindensis, Johnius sp., Strongylura sp.). Congeneric genetic distances were 46-fold higher than conspecific distances, and a DNA barcoding gap was observed. The tree constructed using maximum likelihood clearly displayed phylogenetic signals at different taxonomic levels. Our results indicated that DNA barcodes served as a valuable tool for studying fish diversity and also for the identification and discovery of fish species in the Persian Gulf. The database developed during this study will contribute to assessing fish biodiversity, conservation, and fisheries management. [ABSTRACT FROM AUTHOR]

Around the middle of the nineteenth century, Italian palaeontologists began to investigate fossils of fishes and reptiles from the Middle Triassic outcrops in the vicinity of Monte San Giorgio (Canton Ticino, Switzerland). In 1924, researchers from the University of Zurich started their scientific excavations on the Swiss side. The many fish fossils found since then have often stood in the shadow of the more spectacular and mostly larger fossils of various aquatic reptiles. Beginning around 1980 the fish fossils in the collection of the Palaeontological Institute and Museum of Zurich University have subsequently been brought out of this shadow. The picture presently emerging is that of a species rich fish fauna located in six different fossiliferous beds of Anisian and Ladinian age with a few chondrichthyan, some coelacanth and a wealth of different actinopterygian taxa, many of them well preserved. The ongoing work not only results in taxonomic and systematic novelties, but gives also new insights into their palaeobiology, palaeoecology and palaeobiogeography. [ABSTRACT FROM AUTHOR]

Among vertebrates, sharks exhibit both large and heterogeneous genome sizes ranging from 2.86 to 17.05 pg. Aiming for a better understanding of the patterns and causalities of shark genome size evolution, we applied phylogenetic comparative methods to published genome-size estimates for 71 species representing the main phylogenetic lineages, life-histories and ecological traits. The sixfold range of genome size variation was strongly traceable throughout the phylogeny, with a major expansion preceding shark diversification during the late Paleozoic and an ancestral state (6.33 pg) close to the present-day average (6.72 pg). Subsequent deviations from this average occurred at higher rates in squalomorph than in galeomorph sharks and were unconnected to evolutionary changes in the karyotype architecture, which were dominated by descending disploidy events. Genome size was positively correlated with cell and nucleus sizes and negatively with metabolic rate. The metabolic constraints on increasing genome size also manifested at higher phenotypic scales, with large genomes associated with slow lifestyles and purely marine waters. Moreover, large genome sizes were also linked to non-placental reproductive modes, which may entail metabolically less demanding embryological developments. Contrary to ray-finned fishes, large genome size was associated neither with the taxonomic diversity of affected clades nor with low genetic diversity. [ABSTRACT FROM AUTHOR]

The article discusses a story called "The Mother of the Fish and the prankster" as told by Vicente García, a native speaker of La Laguna. The story is a version of the mermaid story and is set in the area of Carbón. The unique aspect of this version is that the man who gets caught by the Mother of the Fish is a prankster, and the moral of the story is that prankster behavior can lead to the loss of men. The article also provides transcriptions and translations of parts of the story. Additionally, there are tables with phrases in an unidentified language that seem to describe actions related to impaling or taking fish. There is also a document that appears to be a transcription of a conversation or dialogue between two individuals, discussing a person living inside a hill and a mother bringing someone to possess them. The document is likely a linguistic or anthropological study. [Extracted from the article]

The abundance of shark and actinopterygian fossils in the Cretaceous and Paleogene strata of the Atlantic Coastal Plain is well documented; but much remains unknown about the survivorship patterns of these major components of shallow marine faunas in the western Atlantic through the K/Pg mass extinction. To shed light on this subject, we describe an assemblage of new actinopterygian, chondrichthyan, and reptilian microfossils recently recovered from the Maastrichtian Navesink and Maastrichtian-Danian Hornerstown formations at the Jean and Ric Edelman Fossil Park at Rowan University in Mantua Township, New Jersey. The new microfossils clarify extinction patterns across the K/Pg, create temporal and geographic range extensions for several taxa, and expand the known fauna of this regionally-rare and important K/Pg-boundary locality. We report 11 new additions to the vertebrate fauna of Edelman Fossil Park, the first Paleocene record of Saurocephalus lanciformis, the first Cretaceous records of Paralbula marylandica and Palaeogaleus vincenti, and the first recovery of gar and dercetid fish remains from the Paleocene in New Jersey (the last indicating that these fish survived the K/Pg extinction in the western Atlantic). Geographic range extensions include: Notidanodon brotzeni into the Western Hemisphere, Saurocephalus into northeastern North America and Phyllodus paulkatoi to the eastern coast of North America. A dentary of a juvenile alligatorid, Bottosaurus harlani, indicate that the mandible exhibited isometric growth through ontogeny. Our findings generally agree with other studies that these groups were significantly impacted by the extinction event, that extinctions were selective, and recovery was slow. This wealth of novel insights garnered from microfossils in this study highlights their critical importance for elaborating past faunas and illuminating the character of ancient ecosystems. We therefore recommend microsieving as a fruitful method for future faunal studies of shallow-marine strata and predict that such efforts will frequently yield similar important insights. [ABSTRACT FROM AUTHOR]

In electroreceptive jawed vertebrates, embryonic lateral line placodes give rise to electrosensory ampullary organs as well as mechanosensory neuromasts. Previous reports of shared gene expression suggest that conserved mechanisms underlie electroreceptor and mechanosensory hair cell development and that electroreceptors evolved as a transcriptionally related "sister cell type" to hair cells. We previously identified only one transcription factor gene, Neurod4, as ampullary organ-restricted in the developing lateral line system of a chondrostean ray-finned fish, the Mississippi paddlefish (Polyodon spathula). The other 16 transcription factor genes we previously validated in paddlefish were expressed in both ampullary organs and neuromasts. Here, we used our published lateral line organ-enriched gene-set (arising from differential bulk RNA-seq in late-larval paddlefish), together with a candidate gene approach, to identify 25 transcription factor genes expressed in the developing lateral line system of a more experimentally tractable chondrostean, the sterlet (Acipenser ruthenus, a small sturgeon), and/or that of paddlefish. Thirteen are expressed in both ampullary organs and neuromasts, consistent with conservation of molecular mechanisms. Seven are electrosensory-restricted on the head (Irx5, Irx3, Insm1, Sp5, Satb2, Mafa and Rorc), and five are the first-reported mechanosensoryrestricted transcription factor genes (Foxg1, Sox8, Isl1, Hmx2 and Rorb). However, as previously reported, Sox8 is expressed in ampullary organs as well as neuromasts in a catshark (Scyliorhinus canicula), suggesting the existence of lineage-specific differences between cartilaginous and ray-finned fishes. Overall, our results support the hypothesis that ampullary organs and neuromasts develop via largely conserved transcriptional mechanisms, and identify multiple transcription factors potentially involved in the formation of electrosensory versus mechanosensory lateral line organs. [ABSTRACT FROM AUTHOR]

Pseudorhombus elevatus Ogilby, 1912 and P. quinquocellatus Weber and de Beaufort, 1929 (Teleostei: Paralichthyidae) are newly recorded from Japan, based on 35 and two specimens, respectively, from Okinawa Island, Ryukyu Islands. Although both species have previously been recorded from Taiwan, no Japanese records are known to date. Pseudorhombus elevatus is characterized, and readily distinguished from Japanese congeners, by numerous minute teeth on both jaws, three dark blotches along the straight section of the ocular-side trunk lateral line, and dorsal- and anal-fin ray numbers. Pseudorhombus quinquocellatus resembles P. pentophthalmus Günther, 1862 and P. oculocirris Amaoka, 1969, all sharing five dark ocelli on the ocular-side body (two pairs of ocelli above and below the lateral line plus a single ocellus on the posterior portion of the lateral line). However, the former is characterized by strong caniniform teeth on both jaws (vs. no strong caniniform teeth in P. pentophthalmus and P. oculocirris); fewer lower gill rakers (9–11 in Japanese specimens) (vs. 15–21); and two dark skin flaps along the gill opening below the pectoral-fin base (vs. absent). The status of the type specimens of P. quinquocellatus was also considered, all three being regarded as syntypes, in the absence of a formal lectotype proposal. New standard Japanese names, “Maru-ganzō-birame” and “Niten-ganzō-birame,” are proposed for P. elevatus and P. quinquocellatus, respectively, the name “Itsutsume-ganzō” now being referred to P. megalops Fowler, 1934.

The Vaupés River stands out as one of the few within the Amazon basin due to its numerous rapids. These riverine fast-flowing sections not only provide habitat to highly specialized fishes but also function as natural barriers hindering the movement of fish along its course. During a fish-collecting expedition in the lower Vaupés River basin in Colombia, 95 species were registered belonging to 30 families and seven orders. Despite recent inventories in the region, our comprehensive sampling efforts particularly focused on the rapids and associated rheophilic fauna, allowing us to contribute the first records of four fish species in Colombia (Myloplus lucienae Andrade, Ota, Bastos & Jégu, 2016, Tometes makue Jégu, Santos & Jégu, 2002, also first record of the genus, Leptodoras praelongus (Myers & Weitzman, 1956), and Eigenmannia matintapereira Peixoto, Dutra & Wosiacki, 2015) and six presumably undescribed species (i.e., Jupiaba sp., Moenkhausia sp., Phenacogaster sp., Bunocephalus sp., Hemiancistrus sp., and Archolaemus sp.). In this study, a commented list of the ichthyofauna of these environments is presented, as well as a photographic catalog of fish species integrated into the CaVFish Project – Colombia. [ABSTRACT FROM AUTHOR]

We report for the first time three gobioid fishes: Amblygobius semicinctus (Bennett, 1833), Istigobius diadema (Steindachner, 1876), and Yongeichthys nebulosus (Forskål, 1775) from the Gujarat coast of India. We present short descriptions with species diagnostic characters, habitat and present distributions. [ABSTRACT FROM AUTHOR]

Enriching mitochondrial DNA (mtDNA) for sequencing entire mitochondrial genomes (mitogenomes) can be achieved by single long-range PCR. This avoids interference from the omnipresent nuclear mtDNA sequences (NUMTs). The approach is currently restricted to the use of samples collected from humans and ray-finned fishes. Here, we extended the use of single long-range PCR by introducing back-to-back oligonucleotides that target a sequence of extraordinary homology across vertebrates. The assay was applied to five hibernating rodents, namely alpine marmot, Arctic and European ground squirrels, and common and garden dormice, four of which have not been fully sequenced before. Analysis of the novel mitogenomes focussed on the prediction of mitochondrialderived peptides (MDPs) providing another level of information encoded by mtDNA. The comparison of MOTS-c, SHLP4 and SHLP6 sequences across vertebrate species identified segments of high homology that argue for future experimentation. In addition, we evaluated four candidate polymorphisms replacing an amino acid in mitochondrially encoded subunits of the oxidative phosphorylation (OXPHOS) system that were reported in relation to cold-adaptation. No obvious pattern was found for the diverse sets of mammalian species that either apply daily or multiday torpor or otherwise cope with cold. In summary, our single long-range PCR assay applying a pair of back-to-back primers that target a consensus sequence motif of Vertebrata has potential to amplify (intact) mitochondrial rings present in templates from a taxonomically diverse range of vertebrates. It could be promising for studying novel mitogenomes, mitotypes of a population and mitochondrial heteroplasmy in a sensitive, straightforward and flexible manner. [ABSTRACT FROM AUTHOR]

The bilateral asymmetry was analysed on 259 fish specimens comprising six Barbus species collected in June-August 2010 from rivers in western Anatolia. The goals of this study are: (1) to check for the levels of bilateral asymmetry amid the ten morphological features of the six Barbus species and (2) to compare the levels of this asymmetry among the ten localities in western Anatolia. The possibility of applied investigations using bilateral asymmetry and fishes as an indicator of the health of the freshwater systems was also conducted. Statistical analyses have shown that the ten morphological traits chosen for this study exhibit variable levels of bilateral asymmetry in the six Barbus species collected from the ten localities studied. The asymmetry value was highest for snout length and lowest for the prepectoral fin length observed in B. pergamonensis. An increasing tendency in asymmetry levels was exhibited for each of the ten morphological traits in the fish length groups selected for each Barbus species assessed. The result of the individuals being right-handed or left-handed has shown that specific morphological characteristics are either dextral or sinistral or showed no bilateral asymmetry in different Barbus species studied. [ABSTRACT FROM AUTHOR]

The assembly of complete and circularized mitochondrial genomes (mitogenomes) is essential for population genetics, phylogenetics and evolution studies. Recently, Song et al. developed a seed-free tool called MEANGS for de novo mitochondrial assembly from whole genome sequencing (WGS) data in animals, achieving highly accurate and intact assemblies. However, the suitability of this tool for marine fish remains unexplored. Additionally, we have concerns regarding the overlap sequences in their original results, which may impact downstream analyses. In this Letter to the Editor, the effectiveness of MEANGS in assembling mitogenomes of cartilaginous and ray-finned fish species was assessed. Moreover, we also discussed the appropriate utilization of MEANGS in mitogenome assembly, including the implementation of the data-cut function and circular detection module. Our observations indicated that with the utilization of these modules, MEANGS efficiently assembled complete and circularized mitogenomes, even when handling large WGS datasets. Therefore, we strongly recommend users employ the data-cut function and circular detection module when using MEANGS, as the former significantly reduces runtime and the latter aids in the removal of overlapped sequences for improved circularization. Furthermore, our findings suggested that approximately 2× coverage of clean WGS data was sufficient for MEANGS to assemble mitogenomes in marine fish species. Moreover, due to its seed-free nature, MEANGS can be deemed one of the most efficient software tools for assembling mitogenomes from animal WGS data, particularly in studies with limited species or genetic background information. [ABSTRACT FROM AUTHOR]

The telencephalon of ray‐finned fishes undergoes eversion, which is very different to the evagination that occurs in most other vertebrates. Ventricle morphogenesis is key to build an everted telencephalon. Thus, here we use the apical marker zona occludens 1 to understand ventricle morphology, extension of the tela choroidea and the eversion process during early telencephalon development of four teleost species: giant danio (Devario aequipinnatus), blind cavefish (Astyanax mexicanus), medaka (Oryzias latipes), and paradise fish (Macroposus opercularis). In addition, by using immunohistochemistry against tubulin and calcium‐binding proteins, we analyze the general morphology of the telencephalon, showing changes in the location and extension of the olfactory bulb and other telencephalic regions from 2 to 5 days of development. We also analyze the impact of abnormal eye and telencephalon morphogenesis on eversion, showing that cyclops mutants do undergo eversion despite very dramatic abnormal eye morphology. We discuss how the formation of the telencephalic ventricle in teleost fish, with its characteristic shape, is a crucial event during eversion. Research highlights: The developmental events that lead to an everted telencephalon in ray‐finned fishes are not well understood. Here we show that the morphology of the telencephalic ventricle is quite similar between five species of teleosts, being a key event during eversion. We also show the transformation that the telencephalon undergoes from 2 to 4/5 days of development, including growth that leads to an expansion along the rostro‐caudal axis and that results in a fully everted telencephalon. Our results support the idea that these two key events, ventricle formation and telencephalon elongation, are at the core of the formation of an everted telencephalon in teleosts. In addition, we show zebrafish cyclops mutants develop an everted telencephalon despite very abnormal neurulation that alters ventricle and eye morphology. Our results provide experimental basis for the only model of eversion based in development data. [ABSTRACT FROM AUTHOR]

Orbitacolax kyphosi sp. nov. is described based on a single specimen of the female recovered from washing fluid of the brassy chub Kyphosus vaigiensis (Quoy & Gaimard, 1825) (Centrachiformes, Kyphosidae) in Japan. K. vaigiensis is a new host and Kyphosidae is a new host group for the genus. [ABSTRACT FROM AUTHOR]

Across the Tree of Life, most studies of phenotypic disparity and diversification have been restricted to adult organisms. However, many lineages have distinct ontogenetic phases that differ from their adult forms in morphology and ecology. Focusing disproportionately on the evolution of adult forms unnecessarily hinders our understanding of the pressures shaping evolution over time. Non-adult disparity patterns are particularly important to consider for coastal ray-finned fishes, which can have juvenile phases with distinct phenotypes. These juvenile forms are often associated with sheltered nursery environments, with phenotypic shifts between adults and juvenile stages that are readily apparent in locomotor morphology. Whether this ontogenetic variation in locomotor morphology reflects a decoupling of diversification dynamics between life stages remains unknown. Here we investigate the evolutionary dynamics of locomotor morphology between adult and juvenile triggerfishes. We integrate a time-calibrated phylogenetic framework with geometric morphometric approaches and measurement data of fin aspect ratio and incidence, and reveal a mismatch between morphospace occupancy, the evolution of morphological disparity, and the tempo of trait evolution between life stages. Collectively, our results illuminate how the heterogeneity of morpho-functional adaptations can decouple the mode and tempo of morphological diversification between ontogenetic stages. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was the comparative analysis of the parasite communities of new populations of invasive pumpkinseed (Lepomis gibbosus) in western Ukraine with pumpkinseed from Czechia, where populations have rapidly expanded over the last two decades. Methods: Sampling took place at three localities in the western part of Ukraine (i.e. Dobrotvir Reservoir (Vistula basin), Burshtyn Reservoir (Dniester basin), Mynai Pond (Danube basin)) and four in Czechia (i.e. Oxbow D2, Heršpický Pond (Danube basin), and Kolín oxbow and Římov Reservoir (Elbe basin). Results: In total, 11 parasite taxa were recorded in Ukraine and 17 in Czechia. Four species were co-introduced from North America with their host, i.e. the myxosporean Myxobolus dechtiari, the monogeneans Onchocleidus dispar and Onchocleidus similis, and metacercariae of a trematode Posthodiplostomum centrarchi. High dominance indices were related to a high abundance of co-introduced parasites, i.e. O. similis in Mynai pond and P. centrarchi in Dobrotvir Reservoir. Overall abundance of acquired parasites was generally low. Conclusion: This study shows that parasite communities in recently established pumpkinseed populations in the western part of Ukraine and Czechia are less diverse than those established in Europe for decades. The generally low parasite load in these new populations may play an important role in their ability to successfully establish and create strong populations by providing a competitive advantage over local species. [ABSTRACT FROM AUTHOR]