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The Paleo-Tokyo Bay (Kanto Plateau) that persisted during the transgression periods in the Middle-Late Pleistocene is known for its rich marine fauna that accommodated both the warm and cold water taxa brought by the Kuroshio and Oyashio Currents, respectively. However, little is known on the paleoichthyofauna in this area and the processes shaping the marine ichthyofauna of modern southern Kanto. We used fossil fish otoliths and teeth discovered in the Sha’ana Tuffaceous Sand Member belonging to the Chibanian Miyata Formation, exposed at Sha’ana-dai, Miura City, Kanagawa Prefecture, Japan, to reconstruct the paleoichthyofauna and its associated paleoenvironment and explore the content of fish assemblages during this period. The Sha’ana Tuffaceous Sand Member was composed of upper sandy mud and lower muddy sand horizons at the exposure. A total of 1,675 fish remains were collected from this site, of which 1,389 were assigned to 62 distinct taxa (20 orders, 31 families). The taxonomic composition revealed taxa from various environments, including shallow continental shelf, epi- to meso-pelagic settings, and the majority were from a generally temperate climatic zone. Paleoenvironmental analyses suggested that the fish assemblages were from the continental shelf (approximate depth of 100–200 m) in a temperate sea where both warm Kuroshio and cold Oyashio Currents had an influence on the biota. The analysis also showed that two boreal fishes, namely Clupea pallasii and Theragra chalcogramma, once had a wider distribution that extended to the southwestern areas of the Paleo-Tokyo Bay. This study provides a more complete view of the related paleobiogeography of marine fishes during the Chibanian and is essential for reconstructing the evolutionary processes of the rich ichthyofauna in the southern Kanto.

Near-infrared (NIR) light-emitting devices with organic semiconductors have great potential for applications in bio-imaging, telecommunication, night-vision displays, and chemical sensing. Light-emitting electrochemical cells (LECs) have demonstrated the advantages of a simple and solution-processable device architecture, low operation bias, and compatibility with air-stable cathode metals. To obtain pure and efficient NIR EL with an emission peak close to or exceeding 800 nm, we fabricated NIR LECs based on the excimer formation of the red cationic iridium complex (NIRex). NIR LECs that employ neat films of complex NIRex exhibit NIR EL centered at 860 nm. To further improve device efficiency, complex RED is incorporated to disperse complex NIRex to reduce concentration quenching. Increasing the incorporation amount of complex RED (0 to 60 wt%) to disperse the guest complex NIRex leads to blue-shifted EL (ELmax = 860 to 744 nm), an enhanced output power (143 to 637 μW cm−2) and an improved EQE (0.26 to 0.82%). The output power and EQE obtained in this work are rather high among the reported NIR LECs exhibiting EL emission peaks exceeding 750 nm. Therefore, NIR LECs based on excimer formation in thin films of cationic iridium complexes have great potential as efficient NIR light sources.

Despite the frequent occurrence of fish fossils in the field, related studies are noticeably rare in Taiwan. The scant fossil record of fish in the literature sharply contrasts the high diversity o...

Solid-state light-emitting electrochemical cells (LECs) have several advantages, such as low-voltage operation, compatibility with inert metal electrodes, large-area flexible substrates, and simple solution-processable device architectures. However, most of the studies on saturated red LECs show low or moderate device efficiencies (external quantum efficiency (EQE)

Solid-state near-infrared (NIR) light-emitting devices have recently received considerable attention as NIR light sources that can penetrate deep into human tissue and are suitable for bioimaging and labeling. In addition, solid-state NIR light-emitting electrochemical cells (LECs) have shown several promising advantages over NIR organic light-emitting devices (OLEDs). However, among the reported NIR LECs based on ionic transition-metal complexes (iTMCs), there is currently no iridium-based LEC that displays NIR electroluminescence (EL) peaks near to or above 800 nm. In this report we demonstrate a simple method for adjusting the energy gap between the highest-occupied molecular orbital (HOMO) and the lowest-unoccupied molecular orbital (LUMO) of iridium-based iTMCs to generate NIR emission. We describe a series of novel ionic iridium complexes with very small energy gaps, namely NIR1-NIR6, in which 2,3-diphenylbenzo[g]quinoxaline moieties mainly take charge of the HOMO energy levels and 2,2'-biquinoline, 2-(quinolin-2-yl)quinazoline, and 2,2'-bibenzo[d]thiazole moieties mainly control the LUMO energy levels. All the complexes exhibited NIR phosphorescence, with emission maxima up to 850 nm, and have been applied as components in LECs, showing a maximum external quantum efficiency (EQE) of 0.05 % in the EL devices. By using a host-guest emissive system, with the iridium complex RED as the host and the complex NIR3 or NIR6 as guest, the highest EQE of the LECs can be further enhanced to above 0.1 %.

This study analyzed the piscivorous diet of bigeye tuna (Thunnus obesus) through species identification of both fish and otolith remains in stomachs of 183 bigeye tuna collected in the western Indian Ocean. A total of 642 fish remains and 1,021 fish otoliths were examined. Prey items identified in the fish and otolith remains were not completely consistent. Although 12 items out of the 53 identified taxa were found in both remains, 20 items of fish remains were not found in otolith remains, and 21 items were added only from the otoliths. The main fish remains were Alepisauridae, which accounted for 13.9%. Most of the otoliths belonged to Myctophidae (49.5%) and Scopelarchidae (21.4%). Three prey items, namely Valenciennellus tripunctulatus, Evermannella sp., and Zenion sp., were recorded for the first time in the diet of bigeye tuna from the region. The otolith remains substantially enhanced the taxonomic resolution of the diet. Bigeye tuna stomach contents were independent of location, depth, and time of catch but varied with tuna size. The proportion of dominant Myctophidae prey items decreased markedly as the tuna size increased, whereas the proportion of Macrouridae increased with size. In addition, larger bigeye tuna were found feeding on larger prey (Electrona risso and Scopelarchus analis), demonstrating that diet changes in both prey composition and size are related to the ontogeny of the fish.

Light-emitting electrochemical cells (LECs) show high technical potential for display and lighting utilizations owing to the superior properties of solution processability, low operation voltage, and employing inert cathodes. For maximizing the device efficiency, three approaches including development of efficient emissive materials, optimizing the carrier balance, and maximizing the light extraction have been reported. However, most reported works focused on only one of the three optimization approaches. In this work, a combinational approach is demonstrated to optimize the device efficiency of LECs. A sophisticatedly designed yellow complex exhibiting a superior steric hindrance and a good carrier balance is proposed as the emissive material of light-emitting electrochemical cells and thus the external quantum efficiency (EQE) is up to 13.6%. With an improved carrier balance and reduced self-quenching by employing the host-guest strategy, the device EQE can be enhanced to 16.9%. Finally, a diffusive layer embedded between the glass substrate and the indium-tin-oxide layer is utilized to scatter the light trapped in the layered device structure, and consequently, a high EQE of 23.7% can be obtained. Such an EQE is impressive and consequently proves that the proposed combinational approach including adopting efficient emissive materials, optimizing the carrier balance, and maximizing the light extraction is effective in realizing highly efficient LECs.

24 pages, 16 figures, 3 tables, supplementary data https://doi.org/10.1016/j.geobios.2018.06.002, Despite extensive studies on the taxonomy of fossil otoliths, the diversity of late Quaternary to Recent sea bottom otolith assemblages remains largely unexplored. Otolith assemblages from bottom sediments of the North-eastern Atlantic (NE Atlantic), central Mediterranean, and Red Sea were described based on a dataset of 9696 identifiable otoliths. Diversity estimators were computed and taxonomic compositions were compared against geographical site and depth gradient. Several species from the Red Sea show previously unnoticed range extensions or ancient occurrences, suggesting that the otolith assemblage requires further exploration in this region. The diversity is high in the NE Atlantic and central Mediterranean, whereas Red Sea assemblages are dominated by few taxa. We find that, departing from Modern fish communities, the richness of otolith taxa peaks at mid-water depths (500–1500 m) and decreases at depths > 2000 m. The lower diversity at shallow water suggests environments not favorable for otolith preservation. The assemblages are geographically distinct, due to unique combinations of mesopelagic taxa specific to each sample area, though areas in the central Mediterranean and middle-latitude NE Atlantic share many taxa. Depth does not seem to structure otolith assemblages in the central Mediterranean because the otolith composition in this region is highly variable at depths < 500 m but poorly variable at greater depths. The discrepancies between otolith thanatocoenoses and fossil assemblages and the potential application for reconstructing ancient fish communities are discussed. Illustrating otoliths that are rarely found in the literature, this study is the first descriptive and comparative diversity analysis on Recent otolith assemblages for the regions of interest, Chien-Hsiang Lin was financially supported by the Ministry of Education, Taiwan, under the title “Government scholarship for overseas study” during his Ph.D. studies. The microscope laboratory at the Dipartimento di Scienze della Terra and Geoambientali, University of Bari Aldo Moro was funded by Potenziamento Strutturale PONa3_00369 “Laboratorio per lo Sviluppo Integrato delle Scienze e delle Tecnologie dei Materiali Avanzati e per dispositivi innovativi (SISTEMA)”

Little is known about long-term changes in coral reef fish communities. Here we present a new technique that leverages fish otoliths in reef sediments to reconstruct coral reef fish communities. We found over 5,400 otoliths in 169 modern and mid-Holocene bulk samples from Caribbean Panama and Dominican Republic mid-Holocene and modern reefs, demonstrating otoliths are abundant in reef sediments. With a specially-built reference collection, we were able to assign over 4,400 otoliths to one of 56 taxa (35 families) though mostly at genus and family level. Many otoliths were from juvenile fishes for which identification is challenging. Richness (by rarefaction) of otolith assemblages was slightly higher in modern than mid-Holocene reefs, but further analyses are required to elucidate the underlying causes. We compared the living fish communities, sampled using icthyocide, with the sediment otolith assemblages on four reefs finding the otolith assemblages faithfully capture the general composition of the living fish communities. Radiocarbon dating performed directly on the otoliths suggests that relatively little mixing of sediment layers particularly on actively accreting branching coral reefs. All otolith assemblages were strongly dominated by small, fast-turnover fish taxa and juvenile individuals, and our exploration on taxonomy, functional ecology and taphonomy lead us to the conclusion that intense predation is likely the most important process for otolith accumulation in reef sediments. We conclude that otolith assemblages in modern and fossil reef sediments can provide a powerful tool to explore ecological changes in reef fish communities over time and space.

Dental material attributed to Palaeoloxodon huaihoensis from the Middle to Late Pleistocene were recovered over decades from the Penghu Channel during commercial fisheries activities. The National Museum of Nature Science (NMNS) has a collection of such dental material, which differs in size and morphology and likely represents ontogenetic variation and growth trajectory of various age groups of P. huaihoensis. However, little is known regarding age determination. By using length of dental material, enamel thickness (ET), and plate counts, we established the method to distinguish the age of the species, which is directly derived from the extant African forest elephant Loxodonta africana. When measuring signs of allometric growth, we found that in both the upper and lower jaws, tooth width was correlated negatively with lamellar frequency but positively with ET. In the same age group, the number of lamellae was higher in P. huaihoensis than in L. africana. The reconstructed age distribution indicated no difference in the upper or lower jaw. Notably, within our sample, P. huaihoensis is skewed towards adult and older individuals with median age between 33–34.5 years and differed significantly from that of Mammuthus primigenius in the European Kraków Spadzista site. This age distribution pattern is speculated to be related to the harsh environmental conditions and intense intraspecific competition among P. huaihoensis during the last ice age.

Reconstruction of the paleoenvironment, using fish otolith assemblages and depending on the modern analogue to provide precise reference information, has been applied on many marine Cenozoic sediments, although the composition of such assemblages on Recent sea bottoms in various environmental settings is still poorly known. This study aims at better understanding the characteristics of otolith thanatocoenoses from Recent sea bottoms. Otolith assemblages taken by box corers or Van Veen grabs on Recent sea bottoms of the Northeastern Atlantic and the North Sea, at various depths and at various latitudes, were analysed. The results reveal that the pelagic and benthic–benthopelagic taxa in the sea bottoms differ markedly in quantity and diversity. The composition of an otolith assemblage differs from location to location, reflecting its biogeographic characteristic, which is mainly determined by pelagic taxa in the oceanic assemblages. The bathymetry, on the contrary, can be better explained from the benthic–benthopelagic taxa, especially in the shallow water assemblages. In addition, otolith size-related distribution along the isobaths is discovered in Lampanyctus crocodilus , in which the proportion of larger specimens in deeper waters increases markedly, confirming the observations of its population stratification in the actual assemblages. The biogeography and bathymetry obtained from the otolith assemblages could therefore, in some cases, be used as an indicator of the present ecology.

The Tortonian fish otoliths of northern Italy have been studied for more than a century and represent one of the best known otolith-based teleost faunas in the Miocene of the Mediterranean Basin. Yet with the growing knowledge on Recent otoliths, an updated taxonomic overview of this fauna is needed. Moreover, new material from hemipelagic Tortonian marls sampled at nine localities is described herein, revealing 109 taxa of which 88 are recognised at species level. Four of these are new: Coryphaenoides biobtusus sp. nov., “Merluccius” rattazzii sp. nov., Neobythites auriculatus sp.nov. and Lesueurigobius stironensis sp. nov. The compilation of previously studied and newly acquired material revealed a total of 118 nominal Tortonian species. At generic level, the fauna is characterised by many modern forms; more than 90% can be assigned to present day genera. At species level, however, more than half of the represented taxa are extinct. Based on the fossil otolith record, the Tortonian fauna of the Mediterranean is most similar to that of the Langhian (Badenian) of the Central Paratethys by sharing many extinct Miocene species, but it is also very close to that of the Pliocene Mediterranean, by sharing many modern Atlantic-Mediterranean forms. The Tortonian fauna is further characterised by many species that are apparently confined to the upper Miocene, resulting in a unique combination of its taxonomic composition.

Otoliths represent a significant biogenic carbonate component in marine sediments that may provide valuable information for paleoenvironmental and biogeographic reconstructions. In spite of their importance, relatively little is still known about the taxonomic composition, abundance and early taphonomic characteristics of recent otolith death-assemblages, which would add to their value to interpret situations in the geological record. Here we present data on the distribution of fish otoliths from bottom sediments collected in the central Mediterranean Sea ranging in depth from 51 to 3300 m. The preservation of otoliths ranges from fresh semi-translucent (white) specimens to dull-coloured (dark) ones, although whitish specimens are predominant across all the samples. This diversity in lustre and colour and at times texture reflects the degree of early taphonomic processes undergone by these aragonitic bodies post-mortem under submarine conditions, never being exposed to diagenetic processes on-land. In general, a correlation with depth is observed, with best preservation observed in otoliths sampled at depths