Sea slugs are always covered in a mucus layer that has various functions including chemical defense that often involves aposematism and mimicry. Therefore, it is necessary for sea slugs to exhibit their body colors and patterns exactly, and the optical properties of mucus should support this requirement. We examined body mucus from heterobranch sea slugs collected in the Okinawan coral reefs. The refractive indices of mucus from 32 species ranged from 1.3371 to 1.3854 and were similar or slightly greater than the refractive index of seawater (ca. 1.34), indicating that light reflectance on the mucus layer is generally small. Moreover, dissolution of mucus into seawater would form a gradient of refractive indices and enhance the reduction of reflectance. We also obtained relative absorption spectra of the mucus from 32 species. In the range of visible light, absorption spectra of mucus suggest that the mucus layer is almost transparent and is not likely to interfere with the body colors. The presence of absorption peaks and/or shoulders in the UV (ultraviolet) range (280-400 nm) indicates that the mucus layer potentially serves as a sunscreen that absorbs UV radiation in 23 species, whereas prominent UV absorption was not found in the other 9 species. In a kleptoplasty sacoglossan Plakobranchus ocellatus, the refractive indices and presence or absence of UV-absorption showed that the optical properties of the mucus varied to some extent but did not show seasonal fluctuation. The UV-absorption in the mucus may also protect kleptoplasts in kleptoplasty sacoglossans. The present results support the importance of mucus as a functional optical layer for the shell-less life of sea slugs.

Rhizocephala is a group of endoparasitic barnacles, the morphological characteristics of which are degenerated, and which has recently undergone active molecular identification. Despite several recent studies of Korean rhizocephalans, a comprehensive analysis of rhizocephalan fauna has not yet been conducted. In this study, we analyzed morphological and molecular characteristics of 64 rhizocephalan samples from 15 decapod hosts sampled across the Korean coast. We found 16 Rhizocephala species of six genera from four Rhizocephala families, i.e., Peltogasterellidae, Peltogastridae, Polyascidae, and Sacculinidae. Combining morphological examination and molecular analysis of mitochondrial cytochrome c oxidase I revealed three new species candidates, i.e., Peltogasterella sp., Peltogaster sp., and Parasacculina sp. 1, and three rhizocephalans that have expanded their distribution range to the Korean coast, i.e., Parasacculina oblonga, Sacculina angulata, and Sacculina gracilis, whose expanded their distribution range to Korean coast. A synthetic update of Korean Rhizocephala fauna including a species checklist and remarks regarding distribution and taxonomy is also presented.

Batellopsis paula gen. et sp. nov., a new hexactinellid-associated alpheid shrimp, is described based on a single specimen collected at a depth of 477-503 m north of Île des Pins, New Caledonia. Batellopsis gen. nov. is part of a clade of four genera all containing hexactinellid-associated species, for which a molecular phylogeny is presented. The evolution of several morphological characters, including orbital teeth, a bulgefossa system on the fingers of the first pereiopod chela, and groups of microserrulate setae on the second pereiopod chela, is discussed in light of phylogenetic results.

Widely distributed, broadcast-spawning Diadema sea urchins have been used as model invertebrate species for studying the zoogeography of the tropical Indo-Pacific. So far, the Indo-Malay archipelago, a wide and geographically complex maritime region extending from the eastern Indian Ocean to the western Pacific Ocean, has been under-sampled. This study aims to fill this sampling gap and uncover the phylogeographic structure of the long-spined sea-urchin D. setosum in the central Indo-West pacific region. D. setosum samples (total N = 718) were collected in 13 sites throughout the Indo-Malay archipelago. We sequenced over 1157 bp of COI gene. The Phylogeographic structure was derived from pairwise ФST estimates using multidimensional scaling and hierarchical clustering analysis; biogeographic hypotheses were tested by AMOVA; genetic relationships between haplotypes were summarised in the form of a minimum-spanning network; and pairwise mismatch distributions were compared to the expectations from demographic and spatial expansion models. All samples from the Indo-West Pacific were of the previously uncovered D. setosum-a lineage. Phylogeographic structure was evident: the Andaman Sea population and the northern New Guinea population were genetically distinct. Subtler but significant haplotype-frequency differences distinguished two populations within the Indonesian seas, distributed in a parapatric-like fashion. The phylogeographic partition observed was insufficiently explained by previous biogeographic hypotheses. The haplotype network showed a series of closely related star-shaped haplogroups with a high proportion of singletons. Nucleotide-pairwise mismatch patterns in the two populations from the Indonesian seas were consistent with both demographic and spatial expansion models. While geographic barriers to gene flow were inferred at the western and eastern extremities of the Indo-Malay archipelago, the subtler parapatric pattern observed within the Indonesian seas indicated restriction in gene flow, in a fashion that can hardly be explained by geographic isolation given the dynamic current systems that cross this region. Our results thus raise the hypothesis of subtle reproductive isolation between ecologically incompatible populations. While the coalescence pattern of the Andaman-Sea population suggested demographic stability over evolutionary timescales, that of the two populations from the Indonesian seas indicated recent population expansion, possibly linked to the rapid changes in available D. setosum habitat caused by sea-level oscillations in the late Pleistocene. The phylogeographic patterns observed in this study point to likely allopatric differentiation in the central Indo-West Pacific region. Genetic differences between populations were likely reinforced during interglacials by some form of reproductive isolation.

Brakemyia metallica gen. et sp. nov. (Diptera, Milichiidae) is described and illustrated based on male and female specimens reared from carton nests of the ant Azteca aff. chartifex Forel (Formicidae: Dolichoderinae). The new genus is widely distributed in the Brazilian Amazon, and it can be readily distinguished from the other Neotropical genera by the broadened lunule, which extends well posterior of the antennae, and the hypandrial complex parallel to epandrium.

In this study, we investigated cause-specific temporal and spatial trends in sea turtle strandings in New Caledonia. Five species of sea turtles were recorded in the 406 strandings documented between January 1999 and March 2021. Green turtles represented the majority of the stranded species (68%), reflecting the importance of the resident green turtle population in New Caledonian waters. Nearly half of the individuals stranded were juveniles (48%). The great majority of strandings were recorded in the South Province, the most populous province of New Caledonia (73%). The main causes of the strandings were classified as unknown (50%), followed by poaching (17%), by-catch (15%), collision (10%), natural (8%), plastic ingestion (0.5%) and other (0.5%). This study contains the first official record of the presence and relative importance of fibropapilloma in New Caledonia, but we could not determine if it was the cause of death for the stranded individuals. Two individuals, after necropsies, were found to have ingested plastic (one in 2011 and the other in 2020). This is the first record of plastic ingestion for sea turtles in New Caledonia. Three significant trends were also found during the study: an increase in the number of individuals reported in the study since 2004; a seasonal effect, with most strandings occurring in summer (November to January); and stranding hotspots. Rehabilitation allowed for 35% of individuals found alive to be released back into the wild. This study suggests that mitigation strategies such as "go slow" zones and a robust stranding network should be put in place in New Caledonia.

The family Fulgoridae belongs to the order Hemiptera, superfamily Fulgoridea, with approximately 770 described species worldwide. Their extraordinary appearance attracts the attention of both entomologists and the public. In addition to the evolutionary issue of their special appearance, certain species are also considered notorious pests (e.g., Lycorma delicatula). Several issues widely exist in previous taxonomic studies of lanternflies: (1) application of uncertain morphological characters leads to synonymy or misidentification; (2) descriptions of male genitalia are incomplete; (3) information of nymphal morphology is insufficient. Therefore, this study aims to provide a comprehensive taxonomic study of Fulgoridae from Taiwan. In this study, eight species in six genera from Taiwan were reported, of which Limois westwoodii was recorded for the first time from Taiwan. Lycorma olivacea was proposed as a new junior synonym of L. meliae. The fifth-instar nymph of Saiva formosana was described for the first time. Detailed descriptions of these lanternflies and an identification key to adults of Fulgoridae from Taiwan were also included.

Phytoparasitic mites of the superfamily Eriophyoidea Nalepa live and feed on mature leaf surfaces, between leaf bud scales, and (though less commonly) on flowers or fruits. In this study, we focused on the seasonal associations of two eriophyoid species, Shevtchenkella serrata (Nalepa 1892) with the Norway maple tree (Acer platanoides L.), and Brevulacus reticulatus Manson 1984 with the common oak (Quercus robur L.). These species have complex life cycles with two morphologically different, seasonal female forms, the protogyne and deutogyne. In B. reticulatus, both forms retain all the major generic characteristics but in S. serrata only the protogynes conform to the diagnosis of Shevtchenkella, whereas the deutogynes have the typical traits of Anthocoptes. We confirmed the conspecificity of the protogynes and deutogynes of both eriophyoid species by sequencing a barcode fragment of the Cox1 gene from which we obtained four pairwise identical sequences: ON920305/ON920306 (S. serrata) and ON920307/ON920308 (B. reticulatus). In addition, taxonomical studies on Shevtchenkella and Brevulacus resulted in new synonymies and combinations: (1) Oxypleurites obtusus Roivainen 1947 is considered a deutogyne of S. serrata and treated as a junior synonym of S. serrata; (2) two rhyncaphytoptine species from North America are transferred from the genus Rhyncaphytoptus to Brevulacus: B. albus (Keifer 1959) comb. nov. and B. atlanticus (Keifer 1959) comb. nov.; and (3) one species, B. salicinus Soika et al. 2017, is excluded from Brevulacus and transferred to Rhyncaphytoptus: Rhyncaphytoptus salicinus (Soika et al. 2017) comb. nov. Apart from distinct morphological deuterogyny in S. serrata and B. reticulatus, we observed the persistent association of S. serrata with the generative organs of the maple tree, A. platanoides, leading to transmission to the next host generation via the seed-containing winged fruits (samaras) and subsequent colonization of seedlings. In B. reticulatus, similar synchronization with host-plant dispersal was not detected; however, in mid-summer, temporary colonization of immature acorns and feeding was observed. Additional studies conducted in various ecosystems and including different ecological groups of plants, especially anemochorous plants, are needed to estimate the frequency of the association of eriophyoids with plant generative organs, seeds and seedlings to better understand what role in mite ecology such associations may play.

Decma fissa is the most widely distributed species of the genus Decma occuring in southern China. This study presents the first phylogeographic work of D. fissa based on COI, Cytb and ITS sequence. We examined genetic diversity with ITS and mitochondrial sequence respectively, and phylogenetic work was based on the mitochondrial data. A high-level genetic diversity was revealed based on mitochondrial data but a low-level diversity was shown with ITS sequence. For the mitochondrial data, divergence time analysis displayed five lineages. Based on the Mantel test, geographic and genetic distances among D. fissa populations revealed a significant positive correlation. Bayesian skyline plot (BSP) analyses implied that none of three major lineages of D. fissa was seemingly affected by the last glacial maximum (LGM, 0.015-0.025 Mya). Ecological niche modeling was used to predict the distribution of D. fissa in four periods (LGM, Mid-Holocene, current and 2070) in China. Analysis of the ancestral area reconstruction indicated that D. fissa occurred in the South China area.

The hydrozoan family Eirenidae is known scientifically for its morphological plasticity and challenges in species identification. We used an integrative taxonomic approach based on morphological, molecular and life history evidence to systematically assess field-collected medusae of Eirene menoni Kramp 1953 and captive raised polyps of both E. menoni and E. lacteoides Kubota and Horita 1992. Following morphological review, we updated the genus description to include the presence of rudimentary bulbs (warts) on the ring canal in at least eight of the 24 valid Eirene species. We propose the potential for the mature E. menoni hydrotheca to develop into a gonotheca. However, this proposal will require additional study for verification. We provide validated distribution records from the Indo-Pacific Ocean for E. menoni,and updated collection records for E. lacteoides from the Yellow and East China Seas, and public aquaria-cultured specimens from Japan and Hawaii, using cytochrome c oxidase I (COI) sequences that we generated and compared with those from GenBank. The COI gene reliably separated four species, each forming a monophyletic clade with strong bootstrap support and low mean intraspecific molecular divergences (≤ 1%) within clades. However, some of the deeper nodes of the tree remained poorly resolved, and our analysis failed to demonstrate monophyly among eirenid genera Eirene and Tima. Our integrative taxonomic approach is essential in confirming species identity within the family Eirenidae and genus Eirene,and we have also identified a likely range expansion of E. lacteoides to Hawaii.