ABSTRACT The pervasive presence of microplastics in marine ecosystems poses a significant threat to apex predators such as sharks, already vulnerable due to anthropogenic pressures. This study presents the first documented evidence of microplastics within mermaid’s purses, the protective structures nurturing embryonic sharks. Microplastic concentrations were quantified in egg cases from two oviparous shark species, Hasselt’s bamboo shark, Chiloscyllium hasseltii and coral catshark, Atelomycterus marmoratus. The results reveal that all examined egg cases contained microplastics, with significantly higher levels observed in A. marmoratus egg cases (21.42 ± 0.86 particles per egg case) compared to C. hasseltii (16.35 ± 1.82 particles per egg case). Additionally, a positive correlation between microplastic abundance and yolk mass suggests potential implications for embryonic development. Physico-chemical characterization identifies predominance of fibre morphology, dark-coloured microplastics, and rayon polymer type. These findings highlight the urgent need for targeted conservation strategies to mitigate the impacts of microplastic pollution on vulnerable shark populations and marine ecosystems. This study supports informed policies and concerted efforts to safeguard ocean health and preserve the integrity of apex predator populations, emphasizing the interconnectedness of marine ecosystems and the imperative of sustainable stewardship.

Abstract Spider silks are a diverse family of protein-based fibers with exceptional strength, extensibility, and toughness. While dragline (major ampullate) silk has been studied most extensively, aciniform (AC) silk—used for prey wrapping, egg case lining, and web decoration—exhibits the highest toughness of all spider silks yet remains comparatively underexplored. This review summarizes current knowledge of AC silk across multiple length scales, from the molecular organization of AcSp1 spidroins in the gland, to conformational transitions during fiber formation, to the macroscopic mechanics of natural fibers. Insights from spectroscopy (Raman, solution- and solid-state NMR), microscopy, and computational modeling reveal a hybrid “beads-on-a-string” architecture, with α-helical “beads” connected by flexible “string” domains that partially convert to β-sheets during fibrillization. Advances in recombinant expression and spinning methods have clarified the roles of repetitive and terminal domains while enabling biomimetic fiber production. Emerging directions include the discovery of AcSp2, hydration-induced crosslinking unique to AC silk, and chimeric designs that integrate motifs from multiple silk types. Together, these findings establish AC silk as a model for adaptable, high-performance protein-based materials with broad potential in biomedical and engineering applications.

The impact of egg handling and storage temperature on shell eggs stored for 27 weeks: Egg quality

Egg cases in oviparous cartilaginous fishes (sharks, rays, and chimaeras) exhibit diverse morphologies that are closely tied to species-specific reproductive adaptations. However, the diversity and formation mechanisms of these structures remain poorly understood. In this study, we performed a quantitative morphological analysis of egg cases from three species: Okamejei kenojei, Cephaloscyllium sarawakense, and Chiloscyllium plagiosum. The results demonstrated that the egg cases of these species could be distinguished using multiple morphological indices (p < 0.05), supporting species-specificity in egg case morphology. In these species, we observed that egg jelly initially envelops the egg case during early embryonic development and later dissolves, allowing seawater entry-suggesting a conserved reproductive strategy within Elasmobranchii. Furthermore, under artificial breeding conditions, observations of female O. kenojei showed that ovulation occurs before egg case secretion. Specifically, eggs reach the oviduct above the oviducal gland when about half of the egg case has formed. Immunohistochemical staining revealed estrogen and progesterone receptors in the oviductal gland cells. Interestingly, O. kenojei can produce malformed eggs with shark egg case-like features under captive breeding conditions. These findings provide new insights into the species-specificity, timing, and hormonal regulation of egg case formation in cartilaginous fishes, and lay a foundation for future research on their reproductive strategies.

ABSTRACT Objective The channeled whelk Busycotypus canaliculatus is the primary species in the southern New England multispecies whelk fishery and is currently overfished. Here, the definition of maturity as it pertains to size-at-maturity (L50) estimates was reassessed to update the life history traits that were determined from a decade-old stock assessment. Methods Channeled whelk were sampled in Buzzards Bay during the winter of 2021 and seasonally via commercial traps in 2022 and 2023 in three regions of southeastern Massachusetts: Buzzards Bay, Vineyard Sound, and Nantucket Sound. The specimens were dissected to assess size at maturity and life history traits. Results The data showed that reproductive development and maturity were conflated in the previous definitions of maturity and was redefined based on biological principles. The definitions of female maturity that were reported in the literature resulted in an estimated L50 of ∼89 to 105 mm shell width (SW) and ∼154–175 mm shell length (SL), whereas the revised biological definition that we used here resulted in a 28% to 42% decrease in SW (61 to 66 mm) and 26% to 37% decrease in SL (109 to 117 mm) L50. In contrast, the L50 determinations for males remained similar. Throughout this study, more males than females were collected (65 ± 10% [mean ± SD]) because the fishery has removed proportionally more females due to their larger size and higher likelihood to be above the harvestable size limit. Female gonad and nidamental gland indices peaked in the summer, which suggests that the egg cases are laid in the fall. Reproductive phenology did not differ from that which was reported in prior studies on the same populations. Conclusions The results presented here highlight the need for a more precise data-based definition of maturity for channeled whelk, as maturity classifications can drastically alter size-at-maturity estimates and fishery management decisions.

ABSTRACTReproduction in chondrichthyan fishes (sharks, rays, skates, and chimaeras) is generally assumed to be a long-term, energetically costly process, given their slow generation times. However, metabolic costs of reproduction remain poorly understood due to a lack of direct, non-lethal measurements. To address this, we investigated metabolic and physiological changes during oviparous reproduction in five female epaulette sharks (Hemiscyllium ocellatum). We tracked oxygen uptake rates – a proxy for metabolic rate – across a 3-week cycle, capturing data before, during, and after egg case encapsulation and oviposition. We also measured reproductive hormones (testosterone, 17β-estradiol, progesterone) and hematological parameters (hematocrit, hemoglobin concentration). Results revealed a positive but non-significant relationship between metabolic rate and body mass, and contrary to expectations, metabolic rate did not significantly change throughout the 19-day cycle. Hormone levels remained stable, except for a transient testosterone peak early in the cycle, and hematological parameters showed no significant variation. These findings tentatively suggest epaulette sharks maintain reproductive effort without marked increases in metabolic or physiological costs. Continued research under seasonal environmental variation could clarify reproductive energetics in chondrichthyans further. This study provides the first direct measurement of metabolic effects of oviparous reproduction in chondrichthyans, challenging assumptions about energetic demands in this taxon.

ABSTRACT The location of shark egg nursery areas in the Mediterranean Sea is not well known. Moreover, decades of trawling have depleted flat muddy bottoms of both organic (sessile colonial organisms) and inorganic (rocks) three‐dimensional structures in the western Mediterranean Sea. Here, we present observations of 263 egg cases of small‐spotted catshark ( Scyliorhinus canicula ) that were found attached to artificial mooring structures located within a demersal no‐take MPA at 300‐ to 400‐m depth. The area is located within a previously identified suitable habitat for small‐spotted catshark egg nurseries, and where conservation measures, such as a no‐take MPAs, have been implemented to recover the heavily‐impacted ecosystem. However, the slow growth of habitat‐forming sessile organisms combined with previous extraction of rocks and other objects from the seabed is hampering the recovery of these areas and the reproduction of oviparous sharks such as the small‐spotted catshark. Our findings reveal that three‐dimensional artificial structures with ropes and other attachments placed within suitable egg nursery habitat are effectively used by small‐spotted catsharks to complete their reproductive cycle. Passive conservation tools such as no‐take MPA may be coupled with active restoration activities such as the deployment of artificial structures in order to improve the conservation and recovery of oviparous elasmobranchs and other marine fauna.

Diverse activities (predators, scavengers, etc) for acquiring food is called feeding behavior. The aforesaid food or the prey is obtain diversely by different predators with the help of special capabilities (like lion, leopard, hyena, etc) but in praying mantids it is much unique. Praying mantids (Mantodea) is a class of generally large and egregious predatory insects with versatile, unique and special capabilities. They feed upon a diverse form of animals, ranging from mosquitoes to grasshoppers, reptiles and tiny vertebrates. Observing the feeding behaviour of praying mantids under natural conditions is difficult due to their speed, camouflage, low lying in vegetation etc. That’s why this study was under taken to see feeding behavior of three diverse occurring species in Laboratory conditions. The feeding behaviour of preying mantids commonly comprises upon three stages; the search of prey, locating the prey and continuous visual focus, slow movement towards the prey of or waiting for prey to come closer and finally stream fast attack on the prey with their pair of raptorial legs. All this known from their oothecae (egg case) rearing in aerated cadges to hatching. From first nymphal instar to adult; the feeding behaviour of Tenodera attenuata, Sphrodomantis transcausica and Mantis religiosa was documented.

Catsharks are benthic elasmobranchs that share spatial niches with littoral and demersal bony fishes. The genus Schroederichthys includes five species, two of which, S. chilensis and S. bivius, occur in the waters of Chile. These species are morphologically similar and are often misidentified because of their overlapping external features and color patterns. To improve species discrimination, we analyzed the egg case morphology of both species based on 36 egg cases (12 S. chilensis, 24 S. bivius) collected from gravid females captured as bycatch in artisanal fisheries between Iquique and Puerto Montt (July–December 2021). Nine morphometric variables were measured and standardized using the total egg case length. Although the egg cases were similar in general appearance, multivariate analyses revealed significant interspecific differences, with egg case height and anterior border width emerging as the most diagnostic variables. Linear discriminant analysis achieved a 100% classification accuracy within this dataset. To confirm species identity, 24 tissue samples (12 per species) were sequenced for the mitochondrial cytochrome c oxidase subunit I (COI) gene. The haplotypes corresponded to previously published sequences from Chile (S. chilensis) and Argentina (S. bivius), with reciprocal monophyly and 100% bootstrap support. While COI barcoding provided robust confirmation, the core contribution of this study lies in the identification of species-specific egg case morphometrics. Together, these findings establish a dual-track toolkit, egg case morphology for primary discrimination and COI barcodes for confirmatory validation, that can be incorporated into bycatch monitoring and biodiversity assessments, supporting the conservation of poorly known catsharks in the Southeast Pacific.

Apristurus iterum, a new species of deepwater catshark, is described from northeastern Australia. The new species is diagnosed through examination of its unique egg case morphology based on a single whole gravid female specimen and 10 egg cases deposited in different Australian ichthyological collections. This discovery prompted a more detailed investigation of Apristurus specimens collected off Queensland, northeastern Australia. The voucher of the gravid female with two egg cases, previously identified as ‘Apristurus’, collected off southeast Queensland, was designated as the holotype and used to describe the new species. The egg cases of A. iterum n. sp. differ from other Australian congeners by possessing distinct, weakly T‐shaped, longitudinal ridges on the dorsal and ventral surfaces. A recently developed molecular approach was successfully applied to extract viable genetic material from the formalin‐fixed holotype specimen. The extracted DNA underwent high‐volume next‐generation sequencing, and the resulting data were processed using a targeted mitochondrial genome alignment approach to generate a short, 160‐nucleotide fragment of the cytochrome c oxidase subunit I (COI) gene, which was used for maximum likelihood phylogenetic analysis. The phylogenetic relationships and egg case morphology strongly support this species as being most closely related to Apristurus ovicorrugatus from northwestern Australia and Apristurus nakayai from New Caledonia and Papua New Guinea, with these three species representing a new subgroup within the Apristurus brunneus group.

The oviduct gland of cartilaginous fish (sharks, skates, and chimeras) synthesizes a highly cross-linked biomaterial that forms a protective leathery egg case, commonly known as "mermaid's purses." Understanding the tissue structure of this organ is critical for elucidating the synthesis process of this promising material. In this study, we performed a histological investigation of the oviduct gland in an oviparous skate, Okamejei kenojei, using paraffin sectioning to generate three-dimensional morphological data. A total of 654 tissue sections were collected and made open source. Our results reveal that the oviduct gland of O. kenojei exhibits a typical zonal structure. The club and papillary zones account for 7.74% ± 7.58% of the gland, while the baffle zone, the largest region, comprises 25-30 layers of glandular ducts, including serous gland ducts (64.72% ± 5.86%) and mixed-type ducts (0.95% ± 1.74%), predominantly distributed along the lateral margins. The terminal zone represents the smallest region, accounting for 2.17% ± 0.54% of the gland. These findings enhance our understanding of the secretion mechanisms involved in the formation of this natural biomedical material. They also provide a foundation for further studies on marine biological histology and the development of biomimetic materials through comparisons with the oviduct glands of other cartilaginous fish.

The genus Metaphotina Piza, 1964 is revised based on comparative morphology. Three species are recognized: Metaphotina bimaculata (Saussure, 1870), Metaphotina austri Ferraz, Souza-Dias & Rivera, 2023, and a newly described species from Bahia, Brazil, Metaphotina akaraje sp. nov. Three new synonyms of M. bimaculata are established after a detailed analysis of primary type specimens and their taxonomic and nomenclatural history: Acontista brevipennis Saussure, 1872 syn. nov., Acontista rehni Giglio-Tos, 1927 syn. nov., and Metaphotina piracicabensis Piza, 1964 syn. nov. The analysis of distributional records confirm that Metaphotina is associated with semiarid environments across the eastern South American Dry Diagonal, mainly encompassing the Cerrado, Caatinga, and Chaco biomes. Field observations enabled the identification of the egg cases, discovering the ability of females to produce parthenogenetic offspring, and the recognition and formal description of the myrmecomorphic protonymph of M. bimaculata. Notably, we report on nymphs of M. bimaculata feeding on extrafloral nectaries (EFNs), marking the first known instance of praying mantises interacting with these plant structures. A dichotomous key, extensive graphic documentation of intra- and interspecific variation, and distribution maps are provided to facilitate the identification of Metaphotina spp..

Abstract The increasing demand for organic chicken eggs has led to cases of counterfeit organic eggs being sold, often produced using commercially-fed chickens. A reliable and accurate method is therefore required to verify the authenticity of organic eggs. This study aims to determine the authenticity of organic eggs by analyzing emission spectra from eggshells using Laser Induced Breakdown Spectroscopy (LIBS) combined with Artificial Neural Networks (ANN). LIBS was chosen for its modern analytical capability with minimal sample preparation, while ANN provides robust classification support. The samples consisted of organic and non-organic eggshells, collected from five groups with controlled feeding: one entirely organic-fed group (100% organic), a completely non-organic group (0% organic), and three other groups with combined feed. A neodymium-doped yttrium aluminum garnet (Nd-YAG) laser was applied to the samples at 1 ATM pressure, producing plasma in an atmospheric air environment. Emission spectra from the plasma were captured by an Optical Multichannel Analyzer (OMA) for elemental analysis. The ANN model was then built to classify the samples based on the spectral data, successfully demonstrating a good classification ability in distinguishing between sample groups. The elemental composition of eggshell samples included Ca, C, O, P, S, Mg, V, Pb, Cr, Hg, Na, Zn, Cu, N, K, and Sr, with Ca showing the highest intensity due to its abundance. These findings demonstrate the potential of LIBS integrated with ANN for organic egg authenticity verification and suggest its applicability in detecting compositional variations at different authenticity levels.

The skate fauna in the Southwest Atlantic Ocean (SWA; 34–55° S) is represented by ~32 species, many of which share external features that have led to misidentifications and deficient fishery statistics. The use of DNA barcoding to discriminate SWA skate species was explored after 20 years of surveys. COI sequences were subjected to distance-based neighbor-joining (NJ), maximum likelihood (ML), barcode index number (BIN), automatic barcode gap discovery (ABGD), and nucleotide diagnostic character (NDC) analyses. For widely distributed species, a haplotype network was built. Overall, 187 specimens and 31 egg cases from 26 skate species were barcoded. NJ and ML analyses showed that nearly all species exhibited unique barcodes or clusters of closely related haplotypes, except for Psammobatis normani/P. rudis and Dipturus trachyderma/D. argentinensis. The first pair was discriminated by NCD. BIN analysis recovered 17 groups, whereas ABGD recovered 23, better reflecting taxonomic diversity. In summary, 24 species were resolved by COI. Phylogeographic signals were observed for Amblyraja doellojuradoi and Zearaja brevicaudata. Compiling our results with data from BOLD, almost all the species occurring in the area possess barcodes, contributing to completing and curating the BOLD reference library, which constitutes an important tool for resolving taxonomic issues, tracing fishery products, and performing eDNA biomonitoring.

French Guiana (FG) is renowned as one of the most extensively studied and recognized Neotropical regions for Mantodea. Despite comprehensive historical and contemporary collections, several taxa remain known from only one sex. This is the case for the females of Microphotina Beier, 1935 (Photinaidae, Microphotinini), whose elusiveness has prevented full characterization of this little-known lineage of foliage-dwelling praying mantises. In this study, we report and describe the female of Microphotina viridescens (Chopard, 1912), discovered in FG through citizen science efforts. We detail critical diagnostic features to recognize the female of M. viridescens and distinguish it from those of Chromatophotina Rivera, 2010, while reinterpreting wing and genital traits of males to enhance its recognition. The egg case is also described for the first time and compared with those of Chromatophotina awajun Rivera, 2010 and other closely related taxa. We complement taxonomy with general observations on the life history of M. viridescens, reporting habitat preferences, cryptic strategy, parental care, and aspects of its postembryonic development. Taxonomic and systematic considerations are provided along with an updated identification key to Microphotina spp. based on males. Finally, we briefly discuss the pivotal role that citizen science can play in advancing praying mantis biodiversity research.

<scp>EXPRESSION OF CONCERN</scp>: Precopulatory Sexual Cannibalism Causes Increase Egg Case Production, Hatching Success, and Female Attractiveness to Males

There are increasing concerns from scientists and policymakers regarding the potential effects of sound on aquatic life. While mobile species can move away from sound sources, slow-moving or sessile organisms are unable to escape. Many species of elasmobranchs are oviparous and deposit egg cases that remain in a fixed position on or near the seabed with development times ranging from months to over a year. The auditory sensitivity of elasmobranchs has been relatively understudied compared with that of marine mammals and teleost fish, with little known about the effect of sound on adults and almost nothing reported on how sound may impact developing embryos. Therefore, the effect of sound on the behavior of late-stage embryonic little skates (Leucoraja erinacea) and chain catsharks (Scyliorhinus retifer) in their egg case was monitored. Both species reacted to sound prior to hatching. Little skates interrupted tail movements in response to 300 and 400 Hz pure tones as well as playbacks of boat sound, while chain catsharks ceased respiratory movements during boat sound playbacks. Thus, late-stage embryos can detect and are affected by sound, and fisheries managers may need to account for the impact of anthropogenic sound near oviparous elasmobranch breeding grounds.

Brood parasitism can be costly to host fitness, which in turn may favour host strategies that decrease these costs. Duck (Anatinae) nests are often parasitized by eggs of other ducks, and one way that hosts can respond to potentially costly brood parasitism is to move parasitic eggs to the clutch periphery, where egg incubation temperatures can be suboptimal relative to the clutch centre. We explored whether red‐breasted mergansers Mergus serrator use discriminatory egg incubation against parasitic eggs laid by conspecifics in a population where conspecific brood parasitism (CBP) is common. We used isoelectric focusing electrophoresis of egg albumen from entire clutches of 12 parasitized nests to identify parasitic eggs. A randomization test pooling identified parasitic eggs (n = 50) across nests revealed that hosts did not position parasitic eggs along the periphery of clutches or out of the central region more than was expected by chance, and this was the case for parasitic eggs laid both before and after the onset of incubation. Similarly, nest‐level analyses showed that parasitic eggs were random in all but the smallest clutch, which contained one identified parasitic egg. Thus, parasitic eggs were not moved to the periphery of heavily parasitized clutches, where egg temperature gradients between central and peripheral regions of nests are expected to be greatest. Only four eggs (&lt; 0.5% of 1276 eggs) were found buried within nest bowls. Eggs that were removed from nests consisted of parasite and host eggs and were more likely along the periphery of clutches prior to their removal than was expected by chance. Our results indicate that discriminatory egg incubation of parasitic eggs is not a well‐developed tactic for defending against CBP in red‐breasted mergansers, though hosts may rely on certain cues to decide which eggs are to be removed from nests (e.g. addled eggs).

ABSTRACTTo implement effective management and conservation strategies, an understanding of the spatial ecology, habitat preferences and movement of demersal elasmobranchs is required. This study combines a photographic survey obtained from an autonomous underwater vehicle (AUV) with existing bathymetric data to help understand elasmobranch ecology within the Firth of Lorn, western Scotland. This area is within the Loch Sunart to Sound of Jura Marine Protected Area (MPA) and designated for the protection of the critically endangered flapper skate (Dipturus intermedius). Two areas of seabed were surveyed using an AUV in water depths of 110–165 m southwest of the Isle of Kerrera. Eight surveys were conducted in total, four in each area. Each area was surveyed twice over 2 days in October 2020 and twice in 2 days in May June 2021. One day used bait on the seabed (October) whilst all the others had no bait. For each survey, the AUV travelled 17 km at a height of 2 m above the seabed in a lawnmower pattern providing 0.5 km2 photographic coverage for ~2 h per survey. Five elasmobranch species, two scyliorhinids (Scyliohinus canicula and Galeus melastomus) and three rajiformes (D. intermedius, Raja clavata and Leucoraja naevus), were identified from a total of 43 k seabed photographs. In total 42 individual animals and 7 egg cases were observed. Although the AUV had short survey times and small study areas the results are encouraging for AUVs being a useful tool in understanding elasmobranch ecology.

ABSTRACTThis study provides novel data on fecundity and oviposition rate of Rioraja agassizii and complementary information on incubation period in captivity. Two females of R. agassizii were maintained in captivity over 1‐year period. Oviposition rate was 0.28 and 0.26 egg cases per day, and fecundity was 114 and 92 egg cases for each female. Incubation period was determined for two embryos resulting in 105 and 114 days with average incubation temperatures ranging from 17.5°C (± 0.81) to 22.1°C (± 1.32). Captive studies contribute to a better understanding of the reproductive biology and complement investigations carried out in the wild.