Mitochondrial metagenomics reveal the independent colonization of the world's coasts by intertidal oribatid mites (Acari, Oribatida, Ameronothroidea).

Oribatid mites are an ancient group that already roamed terrestrial ecosystems in the early and middle Devonian. The superfamily of Ameronothroidea, a supposedly monophyletic lineage, represents the only group of oribatid mites that has successfully invaded the marine coastal environment. By using mitogenome data and nucleic ribosomal RNA genes (18S, 5.8S, 28S), we show that Ameronothroidea are a paraphyletic assemblage and that the land-to-sea transition happened three times independently. Common ancestors of the tropical Fortuyniidae and Selenoribatidae were the first to colonize the coasts and molecular calibration of our phylogeny dates this event to a period in the Triassic and Jurassic era (225-146 mya), whereas present-day distribution indicates that this event might have happened early in this period during the Triassic, when the supercontinent Pangaea still existed. The cold temperate northern hemispheric Ameronothridae colonized the marine littoral later in the late Jurassic-Early Cretaceous and had an ancient distribution on Laurasian coasts. The third and final land-to-sea transition happened in the same geological period, but approx. 30 my later when ancestors of Podacaridae invaded coastal marine environments of the Gondwanan landmasses.

Systematic position of the genus Metacanthocephalus Yamaguti, 1959 (Palaeacanthocephala: Echinorhynchida) inferred from molecular evidence, with a redescription of Metacanthocephalus ovicephalus (Zhukov, 1960).

The familial affiliation of the echinorhynchid palaeacanthocephalan genus Metacanthocephalus has been uncertain, with the three families Echinorhynchidae, Leptorhynchoididae, and Rhadinorhynchidae having been suggested as its parent taxon. In this study, adult individuals of Metacanthocephalus ovicephalus from the intestine of the cresthead flounder Pseudopleuronectes schrenki (new host) and the dark flounder Pseudopleuronectes obscurus in Hokkaido, Japan, were examined. Using three gene markers (mitochondrial cytochrome c oxidase subunit I; nuclear 18S and 28S rRNA genes) determined from two specimens of M. ovicephalus, a molecular phylogenetic analysis was performed along with relevant sequences available in public databases representing 26 species in eight families of the order Echinorhynchida, along with five species from Polymorphida and two from Eoacanthocephala. The resulting phylogram showed that M. ovicephalus was nested within a clade along with nine species in eight genera (Brentisentis yangtzensis, Dentitruncus truttae, Dollfusentis bravoae, Koronacantha mexicana, K. pectinaria, Leptorhynchoides thecatus, Neotegorhynchus cyprini, Pseudoleptorhynchoides lamothei, and Tegorhynchus [= Illiosentis] sp.). In this paper, we propose i) a set of morphological characters to circumscribe members represented by this clade as a Linnaean higher taxon, ii) to place this taxon at the rank of family, iii) to refer to it as Leptorhynchoididae, and iv) to regard Illiosentidae as a junior synonym of Leptorhynchoididae. Our morphological examination revealed a single vaginal sphincter in M. ovicephalus, a character that was not mentioned in any of the previous literature. By this character, along with geographical distribution and host fish, six congeners currently recognized in Metacanthocephalus can be divided into two groups.

Complete mitochondrial genome of a sea cucumber, Euapta godeffroyi (Echinodermata, Holothuroidea, Apodida, Synaptidae).

We determined the complete mitochondrial genome sequence of a holothurian Euapta godeffroyi belonging to the order Apodida. The complete mitogenome of E. godeffroyi was 16,410 bp in length and consisted of 13 protein-coding genes (PCGs), two ribosomal RNA genes, and 22 transfer RNA genes. The orders of PCGs and rRNAs did not match those of any recorded holothurian mitogenomes. The maximum likelihood (ML) phylogenetic tree placed E. godeffroyi as the sister group to chiridotid species and supported the monophyly of the order Apodida.

Mite secretions from three traditional mite-ripened cheese types: are ripened French cheeses flavored by the mites (Acari: Astigmata)?

The opisthonotal glands of Astigmata contain monoterpenes, aromatics, aliphatics, and other volatile compounds; some of these compounds act as pheromones and have antifungal effects. This study analyzed volatile compounds secreted by mites on three traditional mite-ripened cheeses from producers (Milbenkäse from Germany, Mimolette and Artisou from France). The mites obtained from various traditional ripened French cheeses (Mimolette, Laguiole, Salers, and Cantal vieux) from stores were also investigated. The gas chromatography (GC) profiles of all their hexane extracts, except the Cantal vieux one, showed almost no differences and were identical to that of Tyrolichus casei Oudemans except for trace components. Based on the GC results, the mites of Cantal vieux were identified as Acarus siro L. For the Artisou and Cantal vieux, not studied before, the influence of the mite secretions on their characteristics was investigated by analyzing the headspace volatiles from the cheeses. According to the results, neral secreted from T. casei is the main compound responsible for the lemon-like flavor of the mite-ripened cheeses, which is, hence, due to a component of the mite secretions rather than the fermentation of the cheese itself. Moreover, the compounds secreted by the mites are not directly added to the cheese through ripening as they were not detected in the odors of the Artisou and Cantal vieux after the mites were removed. However, the consumers of the Artisou usually eat also the cheese rind, and thus, can enjoy its lemon-like flavor fully.

Do 'cheese factory-specific' mites (Acari: Astigmata) exist in the cheese-ripening cabinet?

To determine whether the mites used in the ripening process of traditional cheeses are genetically unique to cheese factories, we investigated mites from three types of traditional cheeses, that use mites in the ripening process: 'Würchwitzer Milbenkäse' from Germany and 'Mimolette' and 'Artisou' from France. In addition, traditional ripened cheeses were purchased from cheese specialty stores in France (Mimolette) and Japan ('Laguiole' from France) as well as stores in temporary markets in France ('Salers' and 'Cantal vieux') and the mites obtained from those cheeses were analyzed in this study. Partial sequences of the 28S rRNA gene (28S) were determined and used to reconstruct a phylogenetic tree. Tyrolichus casei, the dominant cheese mite species from the ripening cabinets of three traditional cheese producers and two cheese specialty stores in France and Japan, had identical partial 28S sequences. All specimens from Cantal vieux from a store in the temporary market in France had an identical sequence with Acarus siro and Acarus immobilis in the determined region of the 28S sequences. Mite individuals from Salers from a store in the temporary markets in France shared the same haplotype as Acotyledon paradoxa. For the T. casei individuals from five different localities (19 individuals in total), the nuclear loci were obtained using MIG-seq. More than several thousand genomic regions are amplified simultaneously by multiplex PCR, and targeting regions surrounded by inter-simple sequence repeats (ISSRs) in the genome were sequenced using the MiSeq system (Illumina). SNPs extracted from this genome-wide analysis showed that no genetic structure existed in the populations from any region. Among the five samples from the three regions, which were more than 500 km apart and from completely different environments, the mites had no geographic bias, but all mite individuals were genetically nearly identical. Thus, we found no evidence to support the existence of 'cheese factory-specific' T. casei mites, at least in terms of genetic analysis.

Complete mitochondrial genomes of two snail mite: Riccardoella tokyoensis and R. reaumuri (Acariformes, Prostigmata, Ereynetidae).

We determined the mitochondrial genome sequences of two snail mites, Riccardoella tokyoensis and R. reaumuri. The length of the entire mitogenome of these two species is 15,078 bp and 15,148 bp long, respectively. Both of them contain 13 proteins, two rRNAs, and 22 tRNAs for a total of 37 gene products. The gene order of Riccardoella is able to explain by a single rearrangement event from that of other Eupodina species; the whole region, including both rRNA genes and control region (CR), is inverted at the same position. The CR including a tandem repeat region in both of the mitogenomes of Riccardoella species.

Juvenile morphology of seven intertidal mite species (Acari, Oribatida, Ameronothroidea) from the East Asian region.

The present paper provides information on juvenile stages of seven intertidal oribatid mite species from the East Asian region. Larva and nymphs of the fortuyniid species Fortuynia churaumi, F. shibai, F. rotunda and Alismobates reticulatus are described and details about juvenile morphology of the selenoribatid species, Arotrobates granulatus, Indopacifica taiyo and I. tyida are given. Juveniles of the genus Arotrobates are reported for the first time and strong ventral femoral carinae are supposed to be diagnostic characters. Basically, the conservative morphology of immature stages could be confirmed in every studied taxon and its importance for phylogenetic considerations is emphasized.

Geographical parthenogenesis in the brown alga Scytosiphon lomentaria (Scytosiphonaceae): Sexuals in warm waters and parthenogens in cold waters.

Geographical parthenogenesis, a phenomenon where parthenogens and their close sexual relatives inhabit distinct geographical areas, has been considered an interesting topic in evolutionary biology. Reports of geographical parthenogenesis from land and freshwater are numerous, but this occurrence has been rarely reported from the sea. Brown algae are mostly marine and are thought to include numerous obligate parthenogens; still, little is known about the distribution, origin and evolution of parthenogens in this group. Here we report a novel pattern of geographical parthenogenesis in the isogamous brown alga Scytosiphon lomentaria. Sex ratio investigation demonstrated that, in Japan, sexual populations grew in the coast along warm ocean currents, whereas female-dominant parthenogenetic populations grew mainly in the coast along a cold ocean current. In the two localities where sexual and parthenogenetic populations were parapatric, parthenogens grew in more wave-exposed areas than sexuals. Population genetic and phylogenetic analyses, including those based on genome-wide single nucleotide polymorphism data, indicated that parthenogens have initially evolved at least twice and subsequent hybridizations between the parthenogens and sexuals have generated multiple new parthenogenetic lineages. The origin of the initial parthenogens is not clear, except that it would not be interspecies hybridization. Interestingly, we found that the production of sex pheromones, which attract male gametes, has been independently lost in the initial two parthenogenetic lineages. This parallel loss of the sexual trait may represent the direct origin of parthenogens, or the regressive evolution of a useless trait under asexuality.

Complete mitochondrial genome of the Pacific limpet Cellana nigrolineata (Gastropoda: Patellogastropoda) determined by shotgun sequencing using the Illumina NGS platform.

The Pacific limpet Cellana nigrolineata is one of the most commonly found limpets in the intertidal shores of Japan. Here, we report the full mitogenome sequence of an individual specimen of the species, which was collected from the intertidal rocky beach in the Nada beach of Gobo City, Wakayama, Japan (33.8316 N, 135.1751 E), in 2018. The sequence was determined by the shotgun sequencing method using the NGS Illumina MiSeq platform. The genomic structure of C. nigrolineata is the same as the previously reported congener, C. radiata, which shows a representative Nacellidae and metazoan mitogenomic structures. The mitogenome has all of its 37 genes included in its 16,153 bp, with one control region located between the tRNA-Cys and tRNA-Gly genes. In order to clarify the phylogenetic position of C. nigrolineata in Gastropoda, a data set including the mitogenomes of 10 patellogastropods, 10 non-patellogastropod gastropods, and four outgroups were used in maximum likelihood inferences. Although with some exceptions, the resulting phylogeny supported the monophylies of traditionally accepted gastropod subclasses, and thus confirms the position of C. nigrolineata in Patellogastropoda.

Systematics, distribution and morphology of the newt parasitic water mites of the subgenus Lurchibates Goldschmidt amp; Fu, 2011 (Acari, Hydrachnidia, Hygrobatidae, Hygrobates Koch, 1837), including the description of four new species and a key to all so far known species.

Four new water mite species of the genus Hygrobates, subgenus Lurchibates (Acari, Hydrachnidia, Hygrobatidae) are described. Hygrobates (Lurchibates) macrochela sp. nov. Goldschmidt, Nishikawa Shimano is described in male and female; Hygrobates (Lurchibates) malosimilis sp. nov. Goldschmidt, Nishikawa Shimano is described in male, both new water mite species were collected from newts of the species Pachytriton inexpectatus Nishikawa, Jiang, Matsui Mo, 2011; Hygrobates (Lurchibates) incognitus sp. nov. Goldschmidt, Nishikawa Shimano is described in female collected from newts of the species Paramesotriton guangxiensis (Huang, Tang and Tang, 1983); Hygrobates (Lurchibates) fragmentarius sp. nov. Goldschmidt, Nishikawa Shimano is described in a single severely fragmented specimen (sex could not be determined) collected from a newt of the species Paramesotriton yunwuensis Wu, Jiang, and Hanken, 2010. Principal differences between the subgenus Lurchibates and the nominal subgenus Hygrobates s. str. are illustrated and discussed as well as the sexual dimorphism of Lurchibates. Morphometric analyses confirmed the morphological differences of ten out of the eleven so far described species (H. (L.) fragmentarius could not be included in the analysis); two morphological groups became evident mainly based upon the shape of the anterior coxae. These analyses as well provide an idea of possible phylogenetic relationships among the species. A key to all currently known species of the subgenus Lurchibates is given. So far the subgenus is restricted to SE-Asia, a map showing the distribution of all species is presented.

The first complete mitochondrial genome of the Northern Pacific deep-sea goniasterid sea star Ceramaster japonicus (Sladen, 1889) determined using NGS-based shotgun sequencing.

The full mitogenome of an ethanol-preserved museum specimen of Ceramaster japonicus was determined using the NGS Illumina MiSeq platform. The specimen was collected from Tosa Bay, Japan, facing the Pacific Ocean (33.0781 N 134.0601 E), at 700 m depth in 2011. The mitogenome shows a typical metazoan genomic structure, with all of the 37 genes included in its 16,370 base-long mitogenome. We conducted phylogenetic analyses using a data set including 18 publicly available asteroids rooted against five ophiuroids as outgroups. The result confirms the position of C. japonicus in the order Valvatida. The complete mitogenome of C. japonicus reported here is the first reported for the family Goniasteridae Forbes, 1841.

A new amphibious species of the genus emScolopendra/em Linnaeus, 1758 (Scolopendromorpha, Scolopendridae) from the Ryukyu Archipelago and Taiwan.

In Japan and Taiwan, five valid species of the genus Scolopendra Linnaeus, 1758 have been described: S. morsitans Linnaeus, 1758, S. subspinipes Leach, 1816, S. mutilans Koch, 1878, S. japonica Koch, 1878, and S. multidens Newport, 1844. Recently, an undetermined species was found in the Ryukyu Archipelago and Taiwan. Using molecular phylogenetic analyses with mitochondrial COI and 16S rRNA and nuclear 28S rRNA and 18S rRNA genes as well as conventional morphological examination, we successfully discriminated this sixth species as an independent lineage from S. subspinipes, S. mutilans, and other named congeners from East and Southeast Asia. Therefore, the species was described as S. alcyona Tsukamoto Shimano, sp. nov. Several situational evidences suggest that this species prefers streamside environments and exhibits amphibious behavior.

Two New Species of the Genus Eucorydia (Blattodea: Corydiidae) from the Nansei Islands in Southwest Japan.

Two new species of the cockroach genus Eucorydia Hebard, 1929 from the Nansei Islands in Southwest Japan were compared to two closely related congeners, Eucorydia yasumatsui Asahina, 1971 and Eucorydia dasytoides (Walker, 1868). Eucorydia donanensis Yanagisawa, Sakamaki, and Shimano sp. nov. from Yonaguni-jima Island was characterized by an overall length of 12.5-14.5 mm in males. The dorsal side of the male abdomen was entirely dark purple and there was an obscure orange band running down the middle of the tegmen. Eucorydia tokaraensis Yanagisawa, Sakamaki, and Shimano sp. nov. was characterized by an overall length of 12.0-13.0 mm in males and a distinct orange band running down the middle of the tegmen. Eucorydia yasumatsui, E. donanensis, E. tokaraensis and the zonata population of E. dasytoides were divided into four lineages in a maximum-likelihood tree generated from a dataset concatenated from five (two nuclear, 28S rRNA, histone H3, and three mitochondrial, COII, 12S rRNA, 16S rRNA) genes. We recognized the three Japanese lineages E. yasumatsui, E. donanensis, and E. tokaraensis as distinct species, which were also supported by the pairwise genetic distances (5.4-7.8%, K2P) of the COI sequences. Morphometric analysis was performed on the genitalia. A principal component analysis plot revealed that the sizes of the genitalia in the three Japanese species were similar to each other and smaller than that of the zonata population of E. dasytoides. The analysis also revealed that the three Japanese species were distinguished from each other by combinations of the sizes of L3 and L7 sclerites and the shape of R2 sclerite, with some overlapping exceptions.

Taxonomic amendments of Southeast Asian newt species of the genera Pachytriton, Paramesotriton and Laotriton (Amphibia, Urodela, Salamandridae) parasitized by water mites of the subgenus Lurchibates (Hydrachnidia, Hygrobatidae, Hygrobates).

Hygrobates salamandrarum Goldschmidt, Gerecke and Alberti, 2002 (Acari, Hydrachnidia, Hygrobatidae) is the first-known water mite parasitizing adult newts. After its description, three further species of newt-parasitizing mites were described and the subgenus Lurchibates Goldschmidt and Fu, 2011 was proposed for the group, now containing four newt-parasitizing mites. Until now, each water mite species parasitizes a different newt species (Table 1), suggesting possible mite-newt co-speciation. In order to test this hypothesis, we need an accurate taxonomy of both of the hosts and parasites. However, the taxonomy of those Asian newt genera known to be parasitized by Lurchibates mites has been substantially revised after the initial description of the H. salamandrarum. To account for these taxonomic changes, we here revise the host-parasite species list and amend the host species name as shown in Table 1.

Description of three new water mite species of Hygrobates Koch, 1837 (Lurchibates Goldschmidt amp; Fu, 2011) (Acari, Hydrachnidia, Hygrobatidae), parasitic in newts of the genera Paramesotriton and Pachytriton (Amphibia, Caudata, Salamandridae) from China.

Males and females of three new water mite species of the genus Hygrobates Koch, 1837, subgenus Lurchibates Goldschmidt Fu, 2011 (Acari, Hydrachnidia, Hygrobatidae) are described. The diagnosis of the subgenus is extended based upon the new material. The new species were all just found on one newt species each: Hygrobates (Lurchibates) intermedius sp. nov. Goldschmidt, Nishikawa Shimano was collected from newts of the species Paramesotriton qixilingensis Yuan, Zhao, Jiang, Hou, He, Murphy Che, 2014 from Jiangxi Province, China; H. (L.) robustipalpis sp. nov. Goldschmidt, Nishikawa Shimano on Pachytriton inexpectatus Nishikawa, Jiang, Matsui Mo, 2011 from Guizhou Province, China and H. (L.) pilosus sp. nov. Goldschmidt, Nishikawa Shimano on Paramesotriton yunwuensis Wu, Jiang Hanken, 2010 found in a pet shop.

A new deep-sea species of Flabelligena from off the South Orkney Islands, the Southern Ocean.

BACKGROUND: A new acrocirrid species, Flabelligena hakuhoae sp. nov., is described from off the South Orkney Islands, the Southern Ocean. Individuals of the new species were collected by rock dredging, 2036-2479 m in depth. NEW INFORMATION: The new species can be distinguished from its congeners by the number of branchiae, position and length of paired ventral large papillae and length of body papillae.

Author Correction: Phylogeographic patterns of intertidal arthropods (Acari, Oribatida) from southern Japanese islands reflect paleoclimatic events.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Complete mitochondrial genomes of two water mite species: Hygrobates (H.) longiporus and Hygrobates (rivobates) taniguchii (Acari, Trombidiformes, Hygrobatoidea).

We determined the complete mitochondrial genome sequences of two water mites, Hygrobates (Hygrobates) longiporus and H. (Rivobates) taniguchii. The length of the entire mitogenome of these two species is 13,721 bp and 13,770 bp long, respectively. Both of them contain 13 proteins, two rRNAs, and 22 tRNAs for a total of 37 gene products. The gene order of Hygrobates is almost identical to the two species of Unionicola we included in the analysis, with some difference in the position of transfer RNA genes. Phylogenetic analyses highly support these Hygrobates species form a clade with other species of the Hygrobatoidea.

Phylogeographic patterns of intertidal arthropods (Acari, Oribatida) from southern Japanese islands reflect paleoclimatic events.

The Japanese islands represent one of the world's biodiversity hotspots. Their geological history and present geography resulted in a high number of endemic species in nearly all major metazoan clades. We investigated the phylogeography of three different intertidal mite species from the Ryukyu islands and southern mainland by means of morphometry and molecular genetics. None of the species represents an endemic, nearly all show distributions ranging over at least the southern and central Ryukyus. Two species, Fortuynia shibai and F. churaumi sp. n. clearly represent sister species that are derived from a common Eastern ancestor. Molecular genetic results indicate that these species separated approx. 3 Ma before the opening of the Okinawa trough, whereas F. shibai most likely showed an ancestral distribution stretching from the central Ryukyus across the Tokara strait to Japanese mainland, whereas F. churaumi probably evolved somewhere south of the Tokara strait. Phylogenetic data further indicates that long periods of isolation resulted in heterogeneous genetic structure but subsequent low sea level stands during Pleistocene allowed recent expansion and gene flow between island populations. Comparing these patterns with those of other animals, these tiny wingless mites apparently show better dispersal abilities than partially volant terrestrial organism groups.