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Our new study of the species originally included in the genus Allolepidotus led to the taxonomic revision of the halecomorph species from the Triassic of Perledo, Italy. The morphological variation revealed by the analysis of the type material is sufficient to confirm four different taxa represented in the Perledo Formation. We correct the misunderstanding about the type species of Allolepidotus, which is A. ruppelii and not "A." bellottii as considered in the literature over the past two decades. The latter species was originally placed in the genus Semionotus. Fossils from the Kalkschieferzone of Besnasca/Ca' del Frate (Viggiù-Varese, Italy) and Meride (Ticino, Switzerland) which were referred to Allolepidotus, rather represent a species of Eoeugnathus. Therefore, we transfer the species Semionotus bellottii to that genus and propose the new combination E. bellottii. The second and only other species originally included in the genus Allolepidotus is transferred here to the new genus Perledovatus. The holotype of P. nothosomoides new comb. has been mechanically prepared, revealing additional anatomical information that allows to place this taxon in the halecomorph family Subortichthyidae. The other halecomorph species named from the Perledo Formation, Pholidophorus oblongus and Pholidophorus curionii, have been treated as junior synonyms of E. bellottii, but our analysis indicates that they represent distinct separate taxa. However, due to the loss of the type specimens, it is not possible to decide whether they might have been conspecific with other ray-finned fishes from the Middle Triassic of the Alps. [ABSTRACT FROM AUTHOR]

[Display omitted] • 1. AFM-based biophysical measurements are performed on a neural cell. • 2. Exposure to high-dose carbon dots affects cellular mechanics and morphology. • 3. Actin filaments are disorganized in the cells after exposure to high-dose carbon dots. • 4. Biological studies validate the cytotoxic effects disclosed by AFM. • 5. AFM is a powerful biophysical tool for the study of cell-nanomaterials interactions. Understanding the cytotoxicity of fluorescent carbon dots (CDs) is crucial for their applications, and various biochemical assays have been used to study the effects of CDs on cells. Knowledge on the effects of CDs from a biophysical perspective is integral to the recognition of their cytotoxicity, however the related information is very limited. Here, we report that atomic force microscopy (AFM) can be used as an effective tool for studying the effects of CDs on cells from the biophysical perspective. We achieve this by integrating AFM-based nanomechanics with AFM-based imaging. We demonstrate the performance of this method by measuring the influence of CDs on living human neuroblastoma (SH-SY5Y) cells at the single-cell level. We find that high-dose CDs can mechanically induce elevated normalized hysteresis (energy dissipation during the cell deformation) and structurally impair actin skeleton. The nanomechanical change highly correlates with the alteration of actin filaments, indicating that CDs-induced changes in SH-SY5Y cells are revealed in-depth from the AFM-based biophysical aspect. We validate the reliability of the biophysical observations using conventional biological methods including cell viability test, fluorescent microscopy, and western blot assay. Our work contributes new and significant information on the cytotoxicity of CDs from the biophysical perspective. [ABSTRACT FROM AUTHOR]

Though bioaccumulation of pharmaceuticals by aquatic organisms continues to receive scientific attention, the internal disposition of these contaminants among different tissue compartments of fish species has been infrequently investigated, particularly among fish at different trophic positions. We tested a human to fish biological read‐across hypothesis for contaminant disposition by examining tissue‐specific accumulation in three understudied species, longnose gar (Lepisosteus osseus; piscivore), gizzard shad (Dorosoma cepedianum; planktivore/detritivore), and smallmouth buffalo (Ictiobus bubalus; benthivore), from a river influenced by municipal effluent discharge. In addition to surface water, fish plasma, and brain, gill, gonad, liver, and lateral muscle fillet tissues were analyzed via isotope dilution liquid chromatography tandem mass spectrometry. Caffeine and sucralose, two common effluent tracers, were quantitated at low micrograms per liter levels in surface water, while an anticonvulsant, carbamazepine, was observed at levels up to 37 ng/L. The selective serotonin reuptake inhibitors (SSRIs) fluoxetine and sertraline and primary metabolites were detected in at least one tissue of all three species at low micrograms per kilogram concentrations. Within each species, brain and liver of select fish contained the highest levels of SSRIs compared to plasma and other tissues, which is generally consistent with human tissue disposition patterns. However, we observed differential accumulation among specific tissue types and species. For example, mean levels of sertraline in brain and liver tissues were 13.4 µg/kg and 1.5 µg/kg in gizzard shad and 1.3 µg/kg and 7.3 µg/kg in longnose gar, respectively. In contrast, smallmouth buffalo did not consistently accumulate SSRIs to detectable levels. Tissue‐specific eco‐exposome efforts are necessary to understand mechanisms associated with such marked bioaccumulation and internal dispositional differences among freshwater fish species occupying different trophic positions. Environ Toxicol Chem 2024;43:1894–1902. © 2024 The Author(s). Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]

Unlike adult mammalian cardiomyocytes, cardiomyocytes in teleosts display high proliferative capacity throughout adulthood. This study aimed to identify the immunohistochemical profiles of cardiomyocytes and immune cells in the hearts of Molly fish by assessing the immunolabelling expression of key proteins involved in cell proliferation, differentiation, and tissue protection. The cardiac anatomy of Molly fish includes the atrium, ventricle, and bulbus arteriosus. The expression of SOX9, NF-κB, myostatin, and S100 proteins in myocardial cells indicates the proliferative features of the heart in Molly fish. The bulbus arteriosus is characterized by collagenous chambers and smooth muscle cells that express Ach and iba1. The atrium of Molly fish serves as a storage unit for rodlet cells and immune cells. Rodlet cells displayed immunoreactivity to NF-κB, iba1, Olig2, Ach, and S100 proteins, suggesting their roles in the immune response within the heart. Furthermore, telocytes (TCs) have emerged as a significant component of the atrium of Molly fish, expressing Ach, CD68, S100 protein, and iba1. These expressions indicate the involvement of TCs in multiple signaling pathways that contribute to heart architecture. This study delineates the intricate relationship between cardiomyocytes and innate immune cells in Molly fish. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the occurrence of microplastic in digestive organs (esophagus to intestine) of popular marine commercial fish species: Jack (Caranx SP.), blackspot snapper (Lutjanus fulviflamma), coral grouper (Epinephelus carallicala), golden snapper (Lutjanus johnii) and pickhandle barracuda (Sphyraena jello) from Pangempang Estuary in Indonesia. To separate the microplastic particles, each sample was digested using alkaline digestion solution, filtered on Whatman paper and then dried. Microplastic particles in the processed digestive organ contents were identified and enumerated using a dissecting stereo microscope. Microplastics were observed in 94 % of fish digestive organs sampled: 100 % jacks (n = 10), 80 % blackspot snapper (n = 10), 100 % coral grouper (n = 10), 90 % golden snapper (n = 10) and 100 % pickhandle barracuda (n = 10). In these fish samples we found in average of 41 ± 6.0, 26 ± 11.0, 15 ± 2.0, 11 ± 1.0 and 14 ± 2.0 SE microplastic particles per individual and an average of 499.5 ± 94.4, 501.5 ± 198.8, 83.6 ± 18.4, 79.8 ± 11.6 and 40.2 ± 25.0 SE microplastic particles per kg fish weight, in jacks, blackspot snapper, coral grouper, golden snapper and pickhandle barracuda, respectively. Fiber was the most dominant type accounting for 78.6 % of all observed microplastics. Microplastic beads were not detected. The correlation of the average consumed microplastic and the average fish weight per species showed a negative relationship (R² = 0.36), but was not significant (p-value = 0.28). Our finding suggests that demersal fish like jacks, blackspot snapper and coral grouper may have ingested a higher quantity of microplastic particles compared to pelagic species like pickhandle barracuda. [ABSTRACT FROM AUTHOR]

Engin, S.; Gurkan, S., and Taskavak, E., 2024. Cellular changes in liver tissue of adult common sole (Solea solea L. 1758) in the Aegean Sea, Turkey. Journal of Coastal Research, 40(4), 740–748. Charlotte (North Carolina), ISSN 0749-0208. In this study, cellular changes and biological indices in the liver tissue of the common sole, Solea solea (L. 1758), are investigated based on sex, size groups, and seasons. The specimens used in the study were obtained monthly between 2019 and 2020 from commercial trawlers and small scale–fishing operations in the fishing grounds of Izmir Bay, the Aegean Sea coast of Turkey. A total of 240 common sole fish (166 female, 66 male, 8 immature) were used in this study. In the obtained specimens, the male: female ratio was determined as 0.39:1 (χ2 = 33.19; p > 0.05), whereas the length–weight relationship was calculated as W = 0.009TL2.97 (R2 = 0.86) for females and W = 0.009TL3.27 (R2 = 0.91) for males. Four size groups (19–22, 23–26, 27–30, >30cm) were established in the study. Significant histological changes, such as macrovesicular steatosis degenerations, were observed in the liver tissue of the examined fish, especially in larger size groups. Females exhibited higher levels of condition and hepatosomatic index values compared with males, possibly because they are more susceptible to liver degeneration. During the summer months, liver degeneration is more striking due to hunger among common soles. Based on these results, 36.7% of the specimens caught from fishing grounds in Izmir Bay have normal liver tissues, whereas 11.3% have macrosteosis and 8.3% have a sinusoidal hemorrhage. [ABSTRACT FROM AUTHOR]

The validity of Scolopsis regina Whitley 1937, described from a single specimen from Australia and long treated as a junior synonym of Scolopsis monogramma (Cuvier in Cuvier and Valenciennes 1830), is confirmed in this study. The two species share the following features: 45–48 lateral-line scales; 9–11 total gill rakers on first gill arch; no anteriorly projecting suborbital spine; scaled dorsal area of head reaching anteriorly to between anterior margin of eye and posterior nostril; bony ridge of opercle and lower limb of preopercle scaled; scaled lateral area of head extending to just behind eye; and two longitudinal blue bands connecting anterior margins of eyes when fresh. However, S. regina is distinguished from S. monogramma by having 18–20 (modally 19) scale rows below the lateral line [vs. 17–20 (18) in S. monogramma], 6 or 7 (7) preopercular scale rows below eye [5 or 6 (6)], two distinct brown bands across dorsum of snout after preservation (lower band indistinct), a distinct suborbital blue band from lower margin of eye to upper-jaw lip when fresh (blue band indistinct or absent) and the blue band becoming a distinct brown band after preservation (band disappearing), caudal-fin base dark blue when fresh (yellow), a blue longitudinal band on upper caudal-fin lobe (absent), relatively long upper and lower caudal-fin lobes (relatively short), and a relatively wide marginal blue band posteriorly on caudal fin (relatively narrow). Scolopsis regina is distributed off northern Australia, whereas S. monogramma occurs in East and Southeast Asian waters. [ABSTRACT FROM AUTHOR]

ABSTRACT New technologies have resulted in a better understanding of blood and lymphatic vascular heterogeneity at the cellular and molecular levels. However, we still need to learn more about the heterogeneity of the cardiovascular and lymphatic systems among different species at the anatomical and functional levels. Even the deceptively simple question of the functions of fish lymphatic vessels has yet to be conclusively answered. The most common interpretation assumes a similar dual setup of the vasculature in zebrafish and mammals: a cardiovascular circulatory system, and a lymphatic vascular system (LVS), in which the unidirectional flow is derived from surplus interstitial fluid and returned into the cardiovascular system. A competing interpretation questions the identity of the lymphatic vessels in fish as at least some of them receive their flow from arteries via specialised anastomoses, neither requiring an interstitial source for the lymphatic flow nor stipulating unidirectionality. In this alternative view, the ‘fish lymphatics’ are a specialised subcompartment of the cardiovascular system, called the secondary vascular system (SVS). Many of the contradictions found in the literature appear to stem from the fact that the SVS develops in part or completely from an embryonic LVS by transdifferentiation. Future research needs to establish the extent of embryonic transdifferentiation of lymphatics into SVS blood vessels. Similarly, more insight is needed into the molecular regulation of vascular development in fish. Most fish possess more than the five vascular endothelial growth factor (VEGF) genes and three VEGF receptor genes that we know from mice or humans, and the relative tolerance of fish to whole‐genome and gene duplications could underlie the evolutionary diversification of the vasculature. This review discusses the key elements of the fish lymphatics versus the SVS and attempts to draw a picture coherent with the existing data, including phylogenetic knowledge. [ABSTRACT FROM AUTHOR]

Plastic pollution is one of today's most serious global issues in the aquatic environment and organisms, including entanglements, ingestion, and possible toxicity. The study was carried out to screen and identify the microplastics in some tissues of fish species from Sallari and Hauren Shanu burrow pits in Kano metropolis. A total of 60 fish samples comprising two species; Oreochromis niloticus (n = 30) and Tilapia zilli (n = 30), were collected from sampling sites (Sallari and Hauren Shanu). The fishes' gastrointestinal tract, gills and muscle tissues were collected, screenedand examined using a dissecting microscope for the presence of microplastics. Microplastics were found in all the examined fish tissue samples from both sites. In the samples from Hauren Shanu, 63% of the fish had microplastics in the gastrointestinal tract, 46% in muscle and 36% in the gills. In samples from Sallari, 33% of the fish had microplastics in theirgastrointestinal tract, 16% in muscle and 23% in the gills. Microplastics which include fibers, fragments, microbeads and tyre-dusts were observed in all the examined tissues of Oreochromis niloticus and Tilapia zilli although not significantly different (p > 0.05) between the fish species. The study demonstrates microplastics presence in the fish species and portrays to a large extent some degree of plastic contamination in Hauren shanu and Sallari burrow pits. Further assessments should be done on human food contamination by microplastics and their effects on human health. [ABSTRACT FROM AUTHOR]

Copyright of Mugla Journal of Science & Technology is the property of Mugla Journal of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Natural environments vary, and organisms cope with this variation in two general ways: local adaptation and phenotypic plasticity, although these strategies often overlap and interact. This study explored how local adaptation, phenotypic plasticity, and their interactions shaped phenotypic variation in populations of Poecilia mexicana, an extremophile fish living in adjacent but ecologically divergent habitats. By comparing populations from the wild with fish raised in a common-garden environment, we evaluated how genetic differentiation between populations and plasticity contributed to the phenotypic variation observed in nature. We quantified variation in the size of six organs (brain, eyes, gills, heart, liver, and gastrointestinal tract), routine metabolic rate, and body shape. We found evidence for genetic differences between populations impacting the expression of the majority of traits, in addition to or in interaction with phenotypic plasticity and other predictor variables. Overall, our results suggest that trait divergence between populations was at least in part driven by evolutionary change and not just merely by plasticity induced by environmental differences between habitats. Future studies will have to rigorously test whether evolutionary divergence was caused by natural selection and what traits represent adaptations to the different ecological conditions. [ABSTRACT FROM AUTHOR]

Based on a large comparative data set available from recent studies of goatfish species of the genus Upeneus (Mullidae, Mulliformes) with seven spines in the first dorsal fin, four new species from the area of the Asian Indo-Pacific are described. Initial search for and discovery of the new species was greatly assisted by the recognition of several subgroups within two rather large taxonomic species groups, the pori and the japonicus groups, each consisting of nine previously described species. Two of the new species, Upeneus aurorae n. sp. from Luzon, Philippines, and U. huan n. sp. from Central Vietnam (W Pacific), are characterized by relatively low gill-raker counts, while U. brevignathus n. sp. from off SE Yemen (NW Indian Ocean) has high gill-raker counts. All three species share the typical characteristics of the pori-species group such as height of first dorsal fin decreasing proportionally, pectoral fins shorter or of similar length as pelvic fins, oblique bars on lower caudal-fin lobe present and white, rose-whitish or pale-red barbels in fresh and live fish. The fourth new species, U. andamanensis n. sp. from the Andaman Islands (NE Indian Ocean), mostly resembles U. guttatus and two other species of the japonicus-species group, which all belong to a subgroup characterized by the first dorsal fin being relatively high with subsequent fin elements decreasing disproportionally in height. While no fresh colour information is available for U. brevignathus n. sp., and U. andamanensis n. sp., each of them can be clearly distinguished morphologically and by preserved colour from the most similar species. A list of all valid goatfish species is included, with English common names and remarks to clarify validity judgments. The results are discussed with respect to the usefulness of using taxonomic species groupings for facilitating detection of new species and other purposes in continuing studies of the species diversity of goatfishes. [ABSTRACT FROM AUTHOR]

Background: The larval zebrafish tail fin can completely regenerate in 3 days post amputation. mTOR, the main regulator of cell growth and metabolism, plays an essential role in regeneration. Lots of studies have documented the role of mTOR in regeneration. However, the mechanisms involved are still not fully elucidated. Materials and results: This study aimed to explore the role and mechanism of mTOR in the regeneration of larval zebrafish tail fins. Initially, the spatial and temporal expression of mTOR signaling in the larval fin was examined, revealing its activation following tail fin amputation. Subsequently, a mTOR knockout (mTOR-KO) zebrafish line was created using CRISPR/Cas9 gene editing technology. The investigation demonstrated that mTOR depletion diminished the proliferative capacity of epithelial and mesenchymal cells during fin regeneration, with no discernible impact on cell apoptosis. Insight from SMART-seq analysis uncovered alterations in the cell cycle, mitochondrial functions and metabolic pathways when mTOR signaling was suppressed during fin regeneration. Furthermore, mTOR was confirmed to enhance mitochondrial functions and Ca2 + activation following fin amputation. These findings suggest a potential role for mTOR in promoting mitochondrial fission to facilitate tail fin regeneration. Conclusion: In summary, our results demonstrated that mTOR played a key role in larval zebrafish tail fin regeneration, via promoting mitochondrial fission and proliferation of blastema cells. [ABSTRACT FROM AUTHOR]

The diversity of functional feeding anatomy is particularly impressive in fishes and correlates with various interspecific ecological specializations. Intraspecific polymorphism can manifest in divergent feeding morphology and ecology, often along a benthic–pelagic axis. Arctic charr (Salvelinus alpinus) is a freshwater salmonid known for morphological variation and sympatric polymorphism and in Lake Þingvallavatn, Iceland, four morphs of charr coexist that differ in preferred prey, behaviour, habitat use, and external feeding morphology. We studied variation in six upper and lower jaw bones in adults of these four morphs using geometric morphometrics and univariate statistics. We tested for allometric differences in bone size and shape among morphs, morph effects on bone size and shape, and divergence along the benthic-pelagic axis. We also examined the degree of integration between bone pairs. We found differences in bone size between pelagic and benthic morphs for two bones (dentary and premaxilla). There was clear bone shape divergence along a benthic–pelagic axis in four bones (dentary, articular-angular, premaxilla and maxilla), as well as allometric shape differences between morphs in the dentary. Notably for the dentary, morph explained more shape variation than bone size. Comparatively, benthic morphs possess a compact and taller dentary, with shorter dentary palate, consistent with visible (but less prominent) differences in external morphology. As these morphs emerged in the last 10,000 years, these results indicate rapid functional evolution of specific feeding structures in arctic charr. This sets the stage for studies of the genetics and development of rapid and parallel craniofacial evolution. [ABSTRACT FROM AUTHOR]

A new catfish species, Liobagrus chenhaojuni Chen, Guo & Wu, sp. nov., is described from the Tiaoxi River, a tributary of Taihu Lake, located in Zhejiang Province, China. This description is based on morphological characteristics and phylogenetic analysis. This species belongs to a group defined by the presence of a smooth posterior edge of the pectoral-fin spine and can be distinguished from other species in the group by a unique combination of characteristics, including: an upper jaw longer than the lower jaw; maxillary barbels reaching the middle of the pectoral fin; irregular blotches present on the lateral body; a rounded caudal-fin with a length ranging from 16.5% to 19.9% of the standard length; 39 to 41 post-Weberian vertebrae; and 15 to 17 anal-fin rays. The validity of this new species is further supported by the molecular phylogenetic analysis based on Cytb sequences. [ABSTRACT FROM AUTHOR]

This study investigated the prevalence of Aspergillus sp. in tilapia sold for consumption at Pasarean Village in Bogor District. A total of 50 fish were sampled for further investigation. The clinical signs of fish were eroded fins, gills, haemorrhages, and wounds. The presence of pathogenic fungi was confirmed through fungal isolation from the skin, gills, and cloaca and subsequent culturing on potato dextrose agar. Macroscopic and microscopic observations determined Aspergillus sp. The results showed that four Aspergillus species were identified i.e., A. terreus (2%), A. flavus (4%), A. fumigatus (42%), and A. niger (4%), with the occurrence of co-infection between A. fumigatus and A. flavus (2%); A. fumigatus and A. terreus (2%); and between A. fumigatus, A. flavus, and A. niger (2%) reported a total prevalence of 58%. Further study is necessary to mitigate the crucial impact of fungal diseases in aquaculture systems, leading to effective prevention and control strategies, thus ensuring the safety and sustainability of aquaculture practices in Indonesia. [ABSTRACT FROM AUTHOR]

Copyright of Animal Breeding & Feeding / Állattenyésztés és Takarmányozás is the property of Herman Otto Intezet Nonprofit Kft. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Based on material recently collected in northern Thailand, the present study provides an updated of the genus Baetiella, including Gratia. It comprises six species in Thailand, three of them being new species: Baetiella (Gratia) narumonae, Baetiella (Gratia) sororculaenadinae, Baetiella (Baetiella) bispinosa, Baetiella (Baetiella) baei sp. nov., Baetiella (Baetiella) lannaensis sp. nov. and Baetiella (Baetiella) bibranchia sp. nov. Baetiella (Baetiella) baei sp. nov. can be distinguished from other species by the reduction of the posteromedian protuberances on abdominal tergites I–III, the asymmetrical coniform terminal segment of labial palp, the distal margin of abdominal sternites VII–X each with a row of long, spatulate setae, the dorsal margin of femur with two long, robust setae distally. Baetiella (Baetiella) lannaensis sp. nov. is diagnosed by the posteromedian protuberances present on tergites I–VIII, dorsal margin of femur with a regular row of long, rounded, ciliated setae and body surface covered with numerous, dense, rounded scale-like setae. Baetiella (Baetiella) bibranchia sp. nov. can be separated from other species by coxal gills present at the base of forelegs and midlegs. The molecular study based on the mitochondrial gene COI and a larval key to species of Thai Baetiella are also provided. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) pollution is considered as a globally pervasive threat to aquatic ecosystems and many studies reported this pollution in different aquatic ecosystems. However, studies on MPs pollution in wetlands are still scarce. Therefore, the aim of present study was to investigate the presence of MPs in the surface water, sediment and different fish species of Amir˗Kalayeh wetland, Northern Ian. Surface water and sediment samples were collected from six stations during June to July 2022. Moreover, the gills and gastrointestinal tract (GIT) of 54 fish specimens belonging to four species including Cyprinus carpio, Tinca tinca, Esox lucius and Silurus glanis were analysed. MPs were detected in all samples with an average of 2.15 ± 1.98 items/m3 for surface water, 51.66 ± 32.20 items/kg dry weight for sediments, 0.17 ± 0.17 items/individual for fish GIT and 0.12 ± 0.12 items/individual for fish gills. There was no significant relationship between MPs abundance in surface waters and sediments as well as between MPs abundance in environmental matrices and fish (P > 0.0.5). In terms of feeding habit, no significant differences were observed between the number of MPs found in omnivorous and carnivorous fish species (P > 0.05). Moreover, no significant relationship was detected between the MPs abundance in fish tissues and body size (P > 0.05). MPs were mainly fibers, mostly transparent, and in a range size of 70˗5000 µm. The dominant MPs type was nylon in all samples. This study will help increase our knowledge about MPs pollution in inland freshwater systems and suggests that management policies take essential steps to reduce this insidious problem in freshwater ecosystems. [ABSTRACT FROM AUTHOR]

Rovers, rubyfishes, and bonnetmouths (Emmelichthyidae) comprise a small family of fishes that can be distinguished from other perch-like fishes by their generally red, fusiform bodies, highly protrusible mouths, and large rostral cartilage. Their highly protrusible upper jaws have led ichthyologists to group morphologically similar but distantly related taxa within the Emmelichthyidae and is one of the stunning examples of morphological convergence within perchlike fishes. In 2014, the first and only emmelichthyid from the Red Sea, Emmelichthys marisrubri, was described. This species is diagnosed by 80-83 lateral-line scales, 8 dorsal-fin rays, and 4-5 isolated dorsal spines that are separated from membrane-bound dorsal-fin elements, among other features. While examining the osteology of E. marisrubri, I discovered several differences in the oral jaws, suspensorium, neurocranium, and dorsal fin when compared to other species of rovers. Based on these differences and the results of a phylogenetic analysis, I transfer this taxon to the genus Dipterygonotus within the Lutjanidae and among the fusiliers (formerly Caesionidae), an Indo-Pacific group of fishes that also have highly protrusible upper jaws. [ABSTRACT FROM AUTHOR]

This paper investigates the immersed forces on a fish surface during carangiform locomotion. Numerical simulations were conducted and validated to produce the immersed forces on the surface of the fish. The temporal dynamics of the immersed forces for the steady states of the fish swimming is analyzed with a comparative study based on different fish geometries and motion coefficients. The results demonstrated that under steady undulating, the immersed forces are periodically oscillating, whose magnitudes vary across the fish body. Large forces focus on the edges of the tail tips and the head of the fish during swimming, which are also the regions showing with large vorticities in the fluid. Based on the force distribution, it can be inferred that the source of the propulsion for carangiform is mainly from the rear part of the fish. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this article is to describe a new and unusual species of Neoechinoprhynchus Stiles & Hassall, 1905 from the Arabian Gulf coast off Iraq. Methods: Routine methods for examination of fish hosts and recovery of acanthocephalean parasites were followed. Parasites were cleaned, relaxed overnight in refrigerated water then fixed in cold 70% ethanol. Standard procedure for staining, dehydration, clearing in xylene and mounting in Canada balsam was followed. Results: Neoechinorhynchus miniovalis n. sp. is described from five whole-mounted specimens collected from the mudskipper Boleophthalmus dussumieri Valenciennes (Oxudericidae) captured in Shatt Al-Basrah Canal, Iraq in 2008. It is distinguished from other species of Neoechinorhynchus Stiles and Hassall, 1905 by a combination of the following diagnostic characters: very small ellipsoid trunk with tapering posterior end and correspondingly small size organs; body wall with similar thickness dorso-ventrally; proboscis wider than long with long anterior hooks having prominent roots; hooks in second and third circles much smaller and rootless; receptacle 5–6 times as long as proboscis with a triangular cephalic ganglion at its base; no para-receptacle structure; lemnisci relatively long and equal, not reaching anterior testis; all male reproductive structures contiguous in posterior two-thirds of trunk; testes equatorial and much wider than long; anterior testis smaller than posterior testis; large syncytial cement gland with six giant nuclei; cement reservoir adjacent to anterior end of sperm vesicle adjacent to Saefftigen's pouch. No sexual dimorphism except that the trunk is more rounded in females than in males. The female reproductive system is about one-third as long as the trunk with the selective apparatus in two positions and uterine bell angulating ventrad. Female lemnisci are longer than in males. Comparisons with worldwide and North American-related species that have partially similar features are made. Conclusions: The finding of Neoechinorhynchus miniovalis n. sp. with unusual small body and wide ellipsoid shape acanthocephalan is considered the first acanthocephalan species belonging to Neoechinorhynchus reported from Palearctic region compared to similar seven species reported only from Neotropical (three species), Nearctic regions (two species), far east (one species) and oriental (one species). [ABSTRACT FROM AUTHOR]

Purpose: Specimens of Elthusa from trashfish of the Indian SW coast were described as a new parasitic cymothoid, Elthusa nemo sp. nov., (Crustacea: Isopoda). Later, the branchial cavity of the Blotchfin dragonet Callionymus filamentosus Valenciennes, 1837 were documented as its micro- and macro-habitat (host). Methods: Fresh/live specimens of unidentified cymothoid samples were collected from the trash fishes obtained from Neendakara (08°30.0′ N 76°53.30′ E) fish landing centre, Kollam district, Kerala state, southwest coast of India. After a long search for the host species, we recovered the isopod from the branchial cavity of the deep-sea fish Callionymus filamentosus Valenciennes, 1837 (Callionymiformes: Callionymidae). The new species is described and illustrated based on ovigerous females. Results: Elthusa nemo sp. nov., has the following sets of combinations of characters: body slightly twisted, elongated, dorsal surfaces smooth, nearly twice as long as greatest width; pleon short, ~ 14% body length, 0.8 times as wide as pereon maximum width; widest at pleonite 2 and narrowest at pleonite 1; only pleonite 1, laterally overlapped by pereonite 7 posterolateral expansion and coxa 7; presence of appendix masculina on pleopod 2; uropods 0.8 times as the length of pleotelson; antenna with two plumose setae on article 4. Conclusion: Elthusa nemo sp. nov., is the sixth species of the genus known from Indian waters. [ABSTRACT FROM AUTHOR]

Vibrio vulnificus is an opportunistic pathogen in humans and exhibits pathogenic behavior in several aquaculture fish species. To date, in Brazil, there are no reports of V. vulnificus outbreaks in farmed fish. However, in 2019, sorubim (Pseudoplatystoma sp.) in the grow-out phase with clinical signs and cumulative mortality of 40% was registered. We aimed to identify and characterize the etiological agents of this outbreak. Seven moribund fish were sampled for bacteriological studies, and isolates were obtained from the brain and kidneys. Bacterial identification using matrix-assisted laser desorption ionization mass spectrometry (MALDI-TOF/MS) revealed V. vulnificus. One isolate, RP4, was used for identification via dnaJ and 16S rRNA gene sequencing and antimicrobial susceptibility evaluation. Sorubim juveniles were experimentally challenged with RP4 isolate via intracelomic injection (IC, 107 colony-forming units [CFU] fish−1) and immersion bath (IB, 106 CFU mL−1 for 30 min). Identities to V. vulnificus of dnaJ and 16S rRNA genes by BLAST analysis were higher than 92% and 98%, respectively. Susceptibility to oxytetracycline, florfenicol, and other antimicrobial molecules was also observed. In the IC-challenged group, the mortality rate was 100% with V. vulnificus recovered from fish organs (brain, liver, spleen, and kidney). Additionally, splenic endothelium alterations were observed in the IC group. On the contrary, the control and IB groups did not develop any clinical signs, mortality, or bacterial recovery after 7 days of challenge. To the best of our knowledge, this is the first report of pathogenic V. vulnificus in farmed Pseudoplatystoma sp. [ABSTRACT FROM AUTHOR]

Gut morphology frequently reflects the food organisms digest. Gizzards are organs of the gut found in archosaurs and fishes that mechanically reduce food to aid digestion. Gizzards are thought to compensate for edentulism and/or provide an advantage when consuming small, tough food items (e.g., phytoplankton and algae). It is unknown how widespread gizzards are in fishes and how similar these structures are among different lineages. Here, we investigate the distribution of gizzards across bony fishes to (1) survey different fishes for gizzard presence, (2) compare the histological structure of gizzards in three species, (3) estimate how often gizzards have evolved in fishes, and (4) explore whether anatomical and ecological traits like edentulism and microphagy predict gizzard presence. According to our analyses, gizzards are rare across bony fishes, evolving only six times in a broad taxonomic sampling of 51 species, and gizzard presence is not clearly correlated with factors like gut length or dentition. We find that gizzard morphology varies among the lineages where one is present, both macroscopically (presence of a crop) and microscopically (varying tissue types). We conclude that gizzards likely aid in the mechanical reduction of food in fishes that have lost an oral dentition in their evolutionary past; however, the relative scarcity of gizzards suggests they are just one of many possible solutions for processing tough, nutrient‐poor food items. Gizzards have long been present in the evolutionary history of fishes, can be found in a wide variety of marine and freshwater clades, and likely have been overlooked in many taxa. [ABSTRACT FROM AUTHOR]

Meiosis is a highly conserved feature of sexual reproduction that ensures germ cells have the correct number of chromosomes prior to fertilization. A subset of microtubules, known as the spindle, are essential for accurate chromosome segregation during meiosis. Building evidence in mammalian systems has recently highlighted the unexpected requirement of the actin cytoskeleton in chromosome segregation; a network of spindle actin filaments appear to regulate many aspects of this process. Here we show that Drosophila oocytes also have a spindle population of actin that appears to regulate the formation of the microtubule spindle and chromosomal movements throughout meiosis. We demonstrate that genetic and pharmacological disruption of the actin cytoskeleton has a significant impact on spindle morphology, dynamics, and chromosome alignment and segregation during maturation and the metaphase-anaphase transition. We further reveal a role for calcium in maintaining the microtubule spindle and spindle actin. Together, our data highlights potential conservation of morphology and mechanism of the spindle actin during meiosis. Author summary: The actin cytoskeleton is a fundamental component of eukaryotic cells. During meiosis, cytoplasmic actin has been shown to aid in spindle positioning in order to enable asymmetric division. One largely unexplored role of actin is its contribution during the meiotic segregation of chromosomes. Previously thought to be primarily regulated by the microtubule cytoskeleton, the discovery of a population of actin within the meiotic spindle of mouse and human oocytes has opened an entirely new avenue of investigation within the field of meiosis. Here, we reveal in Drosophila melanogaster oocytes a novel population of meiotic actin. Utilising a combination of genetic and pharmacological approaches, we demonstrate the importance of this spindle actin in the regulation of microtubule spindle morphology and chromosomal segregation during the first metaphase-anaphase transition following egg activation. We further explore the potential input from calcium signalling at the spindle. We thus demonstrate great similarity of spindle actin morphologies and mechanisms when compared with starfish, Xenopus and mammals. This suggests a level of conservation that reflects the fundamental nature of meiosis itself. [ABSTRACT FROM AUTHOR]

This article reports on a rare case of abnormal hyperpigmentation in a freshwater sardine species, Triportheus auritus, from the Amazon basin in Brazil. Hyperpigmentation, characterized by excessive pigmentation in the skin or other tissues, has been observed in various fish species. However, this is the first documented case of hypermelanosis in Amazonian freshwater fishes. The specimen was collected from the Tefé River and showed hyperpigmentation on the scales and skin of the head. The rarity of this abnormality suggests that it may be an individual abnormality rather than a common occurrence in the population. The article provides detailed morphometric data and histological analysis of the specimen. The authors speculate that the survival of the hypermelanic individual may be facilitated by the aquatic lighting conditions of the black water in the Tefé River. [Extracted from the article]

A taxonomic review of five scorpaenid nominal species included in the Neomerinthe bucephalus species group [Neomerinthe amplisquamiceps (Fowler 1938), Neomerinthe bucephalus (Alcock 1896), Neomerinthe kaufmani (Herre 1952), Neomerinthe megalepis (Fowler 1938), and Neomerinthe procurva Chen 1981], characterized by a lateral lacrimal spine, recognized four to be valid (N. amplisquamiceps, N. bucephalus, N. kaufmani, and N. megalepis), with N. procurva regarded as a junior synonym of N. bucephalus. A lectotype was designated for N. bucephalus in this study. The valid species, supported by a molecular analysis based on the mitochondrial marker Cytochrome c Oxidase subunit I, can also be identified from combinations of the following characteristics: numbers of pectoral-fin rays, scale rows in the longitudinal series, scale rows below the lateral line, and scale rows between the sixth dorsal-fin spine and lateral line, eleventh dorsal-fin spine length, caudal-peduncle length and depth, and body coloration. In addition, the new species Neomerinthe harenartis is described based on four specimens collected from Vanuatu. This species, also bearing a lateral lacrimal spine, is distinguished from other Indo-Pacific Neomerinthe by having 19 pectoral-fin rays, 47 or 48 scale rows in the longitudinal series, 6 or 7 scale rows above the lateral line, and body depth 31.0–32.8% of SL, and lacking a second preopercular spine. A key to species in the N. bucephalus species group is given. [ABSTRACT FROM AUTHOR]

A new barbeled dragonfish, Eustomias shunyo sp. nov., is described based on three specimens [219.1–256.4 mm in standard length (SL)] collected at depths of 30–180 m from the Shatsky Rise in the western North Pacific. The new species is included in the subgenus Urostomias Regan and Trewavas 1930 and distinguishable from all congeners by the following combination of characters: 30 dorsal-fin rays; 48–49 anal-fin rays; 9–10 pectoral-fin rays; 7 pelvic-fin rays; 29–31 PV (photophores in ventral series between pectoral- and pelvic-fin insertions); 26–27 AC (photophores from dorsal to anal fin to end of row); 69–72 vertebrae; preanal length 63.7–65.3% SL; head length 9.7–10.1% SL; barbel length 12.2–13.7% SL; single luminous gland on upper margin of caudal fin; stem of barbel lacking external pigmentation except for its proximal portion, and melanophores sparsely scattered around small photophores on ventral side of stem; pale yellow patches arranged in 1 or 2 rows on dorsal and ventral sides of barbel stem; single or pared filaments on dorsal side of distal portion of barbel stem just before terminal bulb; single leaf-shaped dark patch on ventral side of barbel bulb. The revised diagnosis and a key to species of the subgenus Urostomias are presented. [ABSTRACT FROM AUTHOR]

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A taxonomic revision of the genus Centrogenys (family: Centrogenyidae), having previously been regarded as monotypic (also monotypic family) represented by Centrogenys vaigiensis, resulted in the recognition of three species, including two new species from Australia, Centrogenys algrahami, new species, and Centrogenys pogonoskii, new species. The two other nominal species of the genus, Centropristes scorpenoides and Sebastes stoliczkae, were regarded as junior synonyms of C. vaigiensis. Centrogenys vaigiensis is readily distinguished from the two new species by lacking scale patches on the membranes between dorsal-fin spines (a small patch of scales present on each interspinous membrane of the third to last dorsal-fin spines in the two new species). Centrogenys algrahami, new species, is characterized by having fewer body scales, including 31–36 pored lateral-line scales (vs. 37–44 in C. vaigiensis and 39–46 in C. pogonoskii, new species) and 31–36 scale rows in longitudinal series (vs. 36–43 and 39–47), and a slightly greater number of pectoralfin rays 14–16 (modally 15; vs. 12–15 [modally 14] in C. vaigiensis and C. pogonoskii, new species). Moreover, C. pogonoskii, new species, is distinguished from the two congeners by the presence of squamation on the lateral side of the snout (in specimens .34 mm SL), whereas it is naked in the congeners. The status of the three species resulting from the morphological analysis was also strongly supported by molecular evidence of a partial sequence of the COI gene. Centrogenys vaigiensis is widely distributed in the Indo-West Pacific, ranging from Mauritius east to Indonesia and north to southern Japan. In contrast, Centrogenys algrahami, new species, and Centrogenys pogonoskii, new species, are restricted to Australia. [ABSTRACT FROM AUTHOR]

Concentrations of toxic and essential trace elements (Hg, Ni, Cu, Pb, Cr, Cd, Mn, As and Se) were determined in different tissues (muscle, skin and liver) of three commercial fish species (Diplodus sargus, Zeus faber, Pomatomus saltatrix). The concentration of the elements was measured by ICP-MS. Arsenic was the most accumulated element in fish tissues. As concentrations in tissues of all fish species, except muscle and skin of John Dory fish, were higher than the maximum limits (MLs). The highest Se concentrations in all fish tissues were in found in the liver. Mn levels were higher than the maximum limits in all tissues of Sargoz fish, skin of John Dory fish, livers of Bluefish and Big Bluefish. In addition, Cr concentrations in tissues of all fish species were found to be higher than the maximum limits of FEPA and WHO. [ABSTRACT FROM AUTHOR]

The article presents the results of morphometric and molecular genetic studies on the fish species Cottus jaxartensis collected from the Ugam River of the watershed of the Chirchik River (Uzbekistan). The material used was 6 fish samples, with 57-84mm long (average 73.5). The numbers of rays are ID 7-8 and II D 17-18 on the dorsal fins, ventral (V) 5, pectoral (P) 14-15, anal (A) 12, caudal (C) 17-18; the number of pores on lateral lines are 34-36; the coefficient of variation of plastic features is varied up to 0.4-19.2% (average 7.8 %), of which signs o, io, H, h, lca, hD, lP, io/c have high variability, and the rest of the characters had medium and low variability. A comparative study of the nucleotide sequence of the 16S gene of mtDNA of the species C. jaxartensis with the nucleotide sequence of the species C. ricei was carried out from GenBank of the National Center for Biotechnology Information. Between the nucleotides of the 16S region of mtDNA in the species C. jaxartensis and the species C. aleuticus and C. gobio, there are differences of 6 nucleotides, and the difference with the total number of nucleotides is 1.8%; with species C. asper, C. marginatus, C. perplexus, C. poecilopus, C. pollux and C. volki between 9 nucleotides (2.7%); with species C. bairdii, C. beldingii, C. gulosus and C. szanaga between 12 nucleotides (3.6%); with species C. cognatus, C. pitensis and C. reinii between 11 nucleotides (3.5%). The 16S gene of the mtDNA nucleotide sequence data was first placed in the GenBank, and the accession number OR470689 was obtained. [ABSTRACT FROM AUTHOR]

The relationship between sound complexity and the underlying morphology and physiology of the vocal organ anatomy is a fundamental component in the evolution of acoustic communication, particularly for fishes. Among vertebrates, the mammalian larynx and avian syrinx are the best-studied vocal organs, and their ability to produce complex vocalizations has been modeled. The range and complexity of the sounds in mammalian lineages have been attributed, in part, to the bilateral nature of the vocal anatomy. Similarly, we hypothesize that the bipartite swim bladder of some species of toadfish (family Batrachoididae) is responsible for complex nonlinear characters of the multiple call types that they can produce, supported by nerve transection experiments. Here, we develop a low-dimensional coupled-oscillator model of the mechanics underlying sound production by the two halves of the swim bladder of the three-spined toadfish, Batrachomoeus trispinosus. Our model was able to replicate the nonlinear structure of both courtship and agonistic sounds. The results provide essential support for the hypothesis that fishes and tetrapods have converged in an evolutionary innovation for complex acoustic signaling, namely, a relatively simple bipartite mechanism dependent on sonic muscles contracting around a gas filled structure. [ABSTRACT FROM AUTHOR]

The increasing microplastic pollution in the marine environment has raised global concern. The main risk of microplastics in aquatic ecosystem is their bioaccumulation in aquatic organisms. A few studies have reported microplastic pollution in the digestive system of Caspian Sea fish species, but there is no research on sturgeon species, nor on fish gills. We investigated the occurrence of microplastics in the gastrointestinal tract (GIT) and gills of 62 specimens belonging to four species including three teleosts (Cyprinus carpio, Rutilus kutum, and Chelon aurata) and one sturgeon (Acipenser persicus, a valuable endangered species) from the Caspian Sea between January and March 2022. Fish tissues were removed, exposed for 24 h to 10% KOH, and then dried on filter paper. Particles were observed under a stereomicroscope and analyzed by Raman microspectrometry, scanning electron microscopy, and energy‐dispersive spectroscopy. A total of 91 microplastics were detected in the GIT (average of 1.46 ± 1.17 items/individual) and 63 microplastics in the gills (average of 1.01 ± 0.62 items/individual). A significant correlation was not found between the number of microplastics found in both tissues and fish body length, body weight, GIT weight, and gill weight (p > 0.05), except between microplastics isolated from gills and gill weight in C. carpio (rs = 0.707, p = 0.022). The abundance of microplastics in fish followed the order of A. persicus > C. aurata > R. kutum > C. carpio. The microplastics were in the size range of 45 to 5000 µm, with particles of 300 to 1000 µm being the most prevalent; 74.68% of the particles were shaped like fibers, 30.53% were red, and 70.6% were composed of nylon polymer. Environ Toxicol Chem 2023;42:2453–2465. © 2023 SETAC [ABSTRACT FROM AUTHOR]

Since 2006, an ophidiiform larva with an ovoid body, elongate anterior dorsal-fin ray, and long trailing fleshy filament has been identified as Pycnocraspedum squamipinne. Similarly, the larvae of the ophidiid genus Luciobrotula have been tentatively identified since 1988, with posteriorly displaced dorsal fins and bulging or exterilium guts. However, neither of these larval forms morphologically agree with their adult counterparts. Recently, blackwater divers captured and photographed specimens of larval Luciobrotula and Pycnocraspedum off the coast of Hawaiʻi and Florida, making them available for both morphological and molecular sampling. After examining these larvae and analyzing DNA barcode sequences, as well as a newly captured and sequenced adult of Pycnocraspedum phyllosoma, we revise the previously identified "Pycnocraspedum" larvae to species of Luciobrotula. We describe the larvae of Luciobrotula bartschi and Luciobrotula corethromycter for the first time, highlighting an extraordinary loss of multiple anterior dorsal-fin elements in their ontogeny. We also generate the first DNA sequences for L. corethromycter and P. phyllosoma, adding to the depauperate number of sequences available for ophidiiforms. For the previously identified "Luciobrotula" larvae, neither morphological nor molecular characters provide definitive identification other than recovering them among the Bythitidae. We provide new morphological observations, revised descriptions, and generate a phylogeny of ophidiiform fishes based on COI to place these larvae in a phylogenetic context, prompting further investigation into the relationships of the Ophidiiformes using additional genetic markers. Our study emphasizes the importance of blackwater diving to improving our understanding of marine larval fishes and the need for additional molecular sampling of the diverse order of brotulas, cusk-eels, pearlfishes, and their allies. [ABSTRACT FROM AUTHOR]

Obliquogobius trifasciatus sp. nov. (Teleostei: Gobiidae) is described on the basis of three specimens (29.5–30.5 mm in standard length) collected in the East China Sea, northwest of the Ryukyu Islands, southern Japan, in a depth of 115–124 m. The new species is characterized by the following combination of characters: 2nd dorsal and anal fins each with I, 9 rays; head moderate in size, its length 32.8–34.1% of standard length; lateral surface of nape scaled; postorbital pore G of cephalic sensory canal present; gill opening moderate in size, extending anteriorly to level with posterior margin of eye; pelvic fins united medially, with a well-developed connecting membrane (between innermost rays) and frenum (between spines); caudal fin dorsoventrally asymmetrical, lacking a distinct obliquely pointed tip, and with three lowermost branched rays much shorter than other branched rays; three broad black (dark brown in preserved specimens) bands, superposed by yellow chromatophores, on lateral surface of body, anteriormost band located under 1st dorsal-fin base, middle band just behind a vertical line through posterior end of 2nd dorsal-fin base, and posteriormost band on caudal-fin base; a small faint, yellow-tinged dusky blotch on center of caudal peduncle (between middle and posteriormost bands on body); a large black blotch, covering almost entirety of 1st dorsal fin; 2nd dorsal and caudal fins generally pale yellow, without a barred pattern. [ABSTRACT FROM AUTHOR]

A new species of Corydoras is described from the rio Jutaí, Amazon basin, Brazil. The new species can be distinguished from its congeners by having the following features: (I) ventral surface of trunk entirely or almost entirely covered by smallto relatively large-sized coalescent platelets, forming a typical mosaic-like pattern; (II) large, arched dark brown or black patch extending from interopercle region to posterior process of parieto-supraoccipital, transversally crossing the orbit and forming a typical mask-like blotch; (III) absence of conspicuous dark markings on caudal fin; (IV) absence of longitudinal rows of dark blotches on flanks; (V) region of first dorsolateral body plate surrounding posterior process of parieto-supraoccipital clearly lighter than remaining portions of head, forming a V-shaped pattern in dorsal view; (VI) anterior portion of dorsal fin with a conspicuous dark patch; and (VII) anterior portion of dorsal-fin base with conspicuous concentration of dark brown or black chromatophores, forming a dark patch slightly darker than ground color of body. A discussion on the possible positive adaptive value of the color pattern is also provided. [ABSTRACT FROM AUTHOR]

Trichomycterus puna, new species, is described from a small tributary of the Corral Blanco in Catamarca Province, Argentina, as part of an ongoing systematic study of the genus Trichomycterus from the High Andean Plateau or Altiplano-Puna drainages of the southern Central Andes. The new species is distinguished from congeners by the following characters: the odontodes embedded in thick integument that covers interopercle, the premaxillary bone smaller than maxilla, the presence of sesamoid supraorbital with lateral process, the supraorbital sensory pore s3 present, the discontinuous supraorbital sensory canal, 2–3 premaxillary tooth rows, the uniformly dark pigmentation on the trunk, 15 precaudal vertebrae, the skin of trunk with minute thread-like papillae, 7–8 pectoral-fin rays, 9–12 dorsal procurrent caudal-fin rays, 10–11 ventral procurrent caudal-fin rays, the distally unbranched barbels, the wider interorbital distance, 16 pairs of ribs, the first dorsal-fin pterygiophore inserting on vertebra 18, and the first anal-fin pterygiophore inserting on vertebra 21. It closely resembles T. alterus, T. belensis, T. boylei, and T. ramosus from the Puna region. Trichomycterus belensis and T. catamarcensis are recorded from new localities over 3,400 m elevation. [ABSTRACT FROM AUTHOR]

The macroscopic and microscopic morphology of the appendicular skeleton was studied in the two species Raja asterias (order Rajiformes) and Torpedo marmorata (Order Torpediniformes), comparing the organization and structural layout of pectoral, pelvic, and tail fin systems. The shape, surface area and portance of the T. marmorata pectoral fin system (hydrodynamic lift) were conditioned by the presence of the two electric organs in the disk central part, which reduced the pectoral fin surface area, suggesting a lower efficiency of the "flapping effectors" than those of R. asterias. Otherwise, radials' rays alignment, morphology and calcification pattern showed in both species the same structural layout characterized in the fin medial zone by stiffly paired columns of calcified tiles in the perpendicular plane to the flat batoid body, then revolving and in the horizontal plane to continue as separate mono‐columnar rays in the fin lateral zone with a morphology suggesting fin stiffness variance between medial/lateral zone. Pelvic fins morphology was alike in the two species, however with different calcified tiles patterns of the 1st compound radial and pterygia in respect to the fin‐rays articulating perpendicularly to the latter, whose tile rows lay‐out was also different from that of the pectoral fins radials. The T. marmorata tail‐caudal fin showed a muscular and connective scaffold capable of a significant oscillatory forward thrust. On the contrary, the R. asterias dorsal tail fins were stiffened by a scaffold of radials‐like calcified segments. Histomorphology, heat‐deproteination technique and morphometry provided new data on the wing‐fins structural layout which can be correlated to the mechanics of the Batoid swimming behavior and suggested a cartilage‐calcification process combining interstitial cartilage growth (as that of all vertebrates anlagen) and a mineral deposition with accretion of individual centers (the tiles). The resulting layout showed scattered zones of un‐mineralized matrix within the calcified mass and a less compact texture of the matrix calcified fibers suggesting a possible way of fluid diffusion throughout the mineralized tissue. These observations could explain the survival of the embedded chondrocytes in absence of a canalicular system as that of the cortical bone. [ABSTRACT FROM AUTHOR]

The evolution of the vascular system has led to the formation of conducting and supporting elements and those that are involved in the mechanisms of storage and defense against the influence of biotic and abiotic factors. In the case of the latter, the general evolutionary trend was probably related to a change in their arrangement, i.e. from cells scattered throughout the tissue to cells organized into ducts or cavities. These cells, regardless of whether they occur alone or in a cellular structure, are an important defense element of trees, having the ability to synthesize, among others, natural resins. In the tracheid-based secondary xylem of gymnosperms, the resin ducts, which consist of secretory cells, are of two types: axial, interspersed between the tracheids, and radial, carried in some rays. They are interconnected and form a continuous system. On the other hand, in the tracheid-based secondary xylem of monocotyledons, the resin-producing secretory cells do not form specialized structures. This review summarizes knowledge on the morpho-anatomical features of various types of resin-releasing secretory cells in relation to their: (i) location, (ii) origin, (iii) mechanism of formation, (iv) and ecological significance. [ABSTRACT FROM AUTHOR]

The Van fish is an endemic carp species living in Lake Van, one of the largest soda lakes in the world. Fluvalinate is a pesticide used extensively in the Lake Van basin. In the present study, the effects of sublethally applied fluvalinate on mucous cells in Van fish gill tissue after 48, 72, and 96 h were determined histochemically. Histopathological lesions were observed in the gills of the fish exposed to fluvalinate in a time-dependent manner. The concentrations of neutral glycoconjugates, acidic glycoconjugates, sulfated acidic glycoconjugates, and strongly acidic glycoconjugates in the mucous cells increased in the gills of the Van fish during the exposure period. At the same time, the area and number of mucous cells increased during fluvalinate exposure. As a result, fluvalinate caused an increase in mucous secretion and content in Van fish gills. [ABSTRACT FROM AUTHOR]

The elucidation of mechanisms responsible for the reproductive isolation of species is a fundamental part of speciation research. South American poeciliid fishes in the genus Phalloceros represent a promising system in which to study the evolution of reproductive barriers between closely related species. Phalloceros are often found in sympatry with non-sister congeners, and most such species pairs have morphologically divergent female and male genitalia. In recent studies, it has been hypothesized that mismatched genitalia between co-occurring Phalloceros species might act as mechanical barriers to prevent hybridization and might help to explain the diversification of this group. However, this idea has not yet been evaluated empirically with genetic data. Here, we tested this hypothesis using morphological data in conjunction with mitochondrial and nuclear DNA sequence data. Our study focused on Phalloceros anisophallos and Phalloceros leptokeras , two non-sister species that have mismatched genitalia and that occur together in at least four rivers in south-eastern Brazil. Despite the prevalence of hybridization between closely related non-sister species of animals, especially fish, our phylogenetically-based results detected no evidence of mitonuclear discordance and (hence historical hybridization) between the two focal species. Our findings are therefore consistent with the hypothesis that mismatched genitalia prevent hybridization between sympatric species of Phalloceros fishes. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the relationship between lignan biosynthesis and programmed cell death (PCD) of ray parenchyma cells during the heartwood formation of Taiwania (Taiwania cryptomerioides Hayata). Since the PCD of ray parenchyma cells and the synthesis of lignans are the two main processes involved in the formation of heartwood, both of which need to be completed through gene regulation. Based on the results of genomics and bioinformatics analysis, that the PCD of tracheids are induced by genotoxic, and the PCD of ray parenchyma cells is induced by biological factors, such as fungi, bacteria, and viruses, which could induce oxidative stress. According to the results of time−of−flight secondary ion mass spectrometry (ToF−SIMS) analysis, lignans are produced in ray parenchyma cells, and the accumulation of savinin and its downstream lignans might be the cause of PCD in ray parenchyma cells. An in vitro experiment further confirmed that the accumulation of savinin could cause protoplasts of Taiwania's xylem to produce taiwanin A, which is the marker of heartwood formation in Taiwania. Resulting in an increase in reactive oxygen species (ROS) content, which could induce oxidative stress in ray parenchyma cells and potentially lead to PCD. Based on these findings, we conclude that accumulation of savinin could be induced PCD of ray parenchyma cells in heartwood formation in Taiwania. [ABSTRACT FROM AUTHOR]

Polonium (210Po) is the major contributor (with approximately 90%) to the radiation dose from radionuclides contained in the human diet, and it is mostly associated with seafood. This study presents 210Po activity concentrations in the tissues of 16 fish species from the Aegean Sea and Sea of Marmara. Among all species investigated, the highest 210Po activity concentration was 4450 ± 33 Bq kg−1 dry weight (dw) in the digestive tract of anchovy (Engraulis encrasicolus), and the lowest 210Po activity concentration was 1.3 ± 0.6 Bq kg−1 (dw) in the muscle tissue of the thornback ray (Raja clavata). Significant differences in 210Po concentrations were consistently found among the tissues of fish (P < 0.05). In general, the prominent accumulation of 210Po was observed in the digestive tract and liver while the muscle tissue generally displayed the lower concentrations. Polonium concentrations in the internal organs, such as muscle and liver, were related to the feeding ecology of fish and thus are a consequence of 210Po transfer in the food chain rather than 210Po uptake from water. The average 210Po concentration in fish filet was 54.1 Bq kg−1 dw and to attain the recommended limit for the annual committed effective dose (1 mSv year−1) would require the consumption of 1024 kg of mixed fish filet in 1 year, which is unlikely to happen. The highest 210Po activity concentration in the edible part of fish (filet) was determined in the anchovy (E. encrasicolus) but to reach the 1 mSv year−1 limit would require still the consumption of 7.1 kg year−1 of anchovy filet. Similar size specimens of wild and farmed fish, Dicentrarchus labrax and Sparus aurata, were analyzed to assess the differences in 210Po concentrations. Polonium concentrations in the wild fish were several-fold higher than in farmed specimens, these ones fed with fish feed with 210Po content lower than natural food in the sea. Therefore, the current trend of increasing the consumption of seafood from aquaculture seems to be reducing the radiation exposure to 210Po in the human diet that is considered beneficial to public health. [ABSTRACT FROM AUTHOR]

Simple Summary: The study aimed to assess the effect of squalene supplied in feed on the growth performance, health status, and fatty acid profiles of the muscle and liver of Siberian sturgeon, rainbow trout, and Eurasian perch. To achieve our aim, we fed fish with three feeds containing different levels of squalene (0%, 0,5%, 1%). Then, analyses such as hematological and biochemical assays, liver histology, and fatty acid content of muscle and liver were performed. The results that we obtained indicate changes in the values of hematological, and biochemical indicators between groups. Squalene addition influences the nucleocytoplasmic index values in all fish offered feed containing 1% squalene. The PUFA and docosahexaenoic acid increased with both groups where squalene was added. Exogenous squalene increases the content of PUFAs in the liver and muscles of the examined species. Squalene is an antioxidant that plays an essential role in fat metabolism. The study aimed to assess the effect of squalene supplied in feed on the growth performance, health status, and fatty acid profiles of muscle and liver of Siberian sturgeon, rainbow trout, and Eurasian perch. The experimental feeds containing 0%, 0.5%, and 1.0% squalene were prepared for each fish species. Hematological and biochemical indices, liver histology, and fatty acid profiling of muscle and liver were analyzed. Squalene supplementation was safe for fish, and no negative influence on growth status was observed. However, changes in the values of hematological and biochemical indicators were found, including the level of triglycerides in the blood of rainbow trout, and cholesterol in the blood of Eurasian perch. The addition of squalene influences the nucleocytoplasmic index values in all fish offered feed containing 1% squalene. The retention of squalene in the liver and muscle of experimental Siberian sturgeon was observed in both 0.5% and 1.0% squalene levels of feed. The PUFA and docosahexaenoic acid increase was observed in all fish in groups with squalene addition. Dietary squalene increases the content of PUFAs in tissues of the examined species. [ABSTRACT FROM AUTHOR]

The ability to visualise the internal anatomical structures of fish provides important information on their reproductive status and body condition and has made important contributions to many areas of fish biology. Obtaining information on the internal anatomy of fish has traditionally required euthanasia and dissection. Although ultrasonography is now increasingly used to study internal fish anatomy without the need for euthanasia, traditional techniques still require restraint and contact with the animal, both of which are known to cause stress. This has prompted the development of waterproof, contactless and portable equipment to allow ultrasonographic examinations to be carried out in free‐swimming individuals, which also facilitates the application of this tool in wild populations of endangered species. This study reports the validation of this equipment using anatomical examinations of nine manta and devil ray (Mobulidae) specimens landed at fish markets in Sri Lanka. The species studied were Mobula kuhlii (n = 3), Mobula thurstoni (n = 1), Mobula mobular (n = 1), Mobula tarapacana (n = 1) and Mobula birostris (n = 3). The use of this equipment was further validated with ultrasonographic examinations in 55 free‐swimming reef manta rays Mobula alfredi, which enabled maturity status to be quantified in 32 females. Structures successfully identified in free‐swimming individuals were the liver, spleen, gallbladder, gastrointestinal tract, skeletal structures, developing follicles and uterus. The study demonstrated that ultrasonography provided a reliable method of determining both sexual maturity and gestational status in free‐swimming M. alfredi. The methodology induced no detectable signs of disturbance to the animals involved and therefore offers a viable and practical alternative to invasive techniques currently used to study anatomical changes in both captive and wild marine organisms. [ABSTRACT FROM AUTHOR]

The study of marine food web models has increased during the last years, but input data of important groups such as cephalopods are missing sometimes which restricts the quality of the model results. Cephalopods feed on a variety of preys, ranging from small crustaceans to large commercially important fish species. In turn, they are taken by larger invertebrates, fish, cephalopods, marine mammals and seabirds, which emphasizes their important role in various marine food webs. Our study presents stomach content analyses of various cephalopod species from the North Sea and describes their general feeding trends. The results further support the inclusion of cephalopods as predators into food web models to increase our knowledge of the North Sea ecosystem and to improve its management. Our data in combination with observed increasing biomasses of North Sea cephalopods suggest that the impact of cephalopods in the North Sea food web has increased and that large-sized cephalopods have become more important as predators for commercially exploited fish species during recent years. [ABSTRACT FROM AUTHOR]

Summary: In‐vitro studies on emulsifying properties of psyllium (Plantago ovata) husk (PSY) powder at various concentrations using natural actomyosin (NAM) extracted from threadfin bream (Nemipterus sp.) mince were investigated. Emulsion activity and stability indexes were increased with the addition of PSY at 1.25 g/100 mL (PSY‐E1) and 2.50 g/100 mL(PSY‐E2) (P < 0.05). Overall, PSY‐E1 and PSY‐E2 emulsions had the highest turbidity and lower particle size. Moreover, gel properties and consumer acceptability of fish tofu added without and with PSY powder at varying concentrations were also elucidated. No difference in breaking force (Br‐F) was observed between all samples, except tofu added with PSY at 5.00 g/100 g, which had the highest Br‐F (P < 0.05). However, the lowest deformation (De‐F) was also attained for PSY‐T3 (P < 0.05). Colour of fish tofu decreased with augmenting levels of PSY. Microstructure of fish tofu revealed the formation of an unordered network with thicker strands as PSY levels upsurged. Fish tofu containing PSY at 1.25–2.5 g/100 g showed a similar overall likeness score to that of control fish tofu. Therefore, PSY at the optimum level enhanced the emulsion stability. Moreover, PSY at 1.25–2.5 g/100 g could improve gel properties without a negative impact on the consumer acceptability of fish tofu. [ABSTRACT FROM AUTHOR]