The effect of bacteria on interspecific relationships between the euryhaline rotifer Brachionus rotundiformis and the harpacticoid copepod Tigriopus japonicus

Inconsistent results have been obtained on the population growth of Brachionus rotundiformis and Tigriopus japonicus, when results from single-species and two-species mixed cultures are compared. Bacteria growth was not regulated in these experiments, which could be the cause for this. In order to test this possibility, we conducted similar experiments under axenic and synxenic (with presence of one species of bacteria) conditions. The population growth of B. rotundiformis was suppressed by the presence of T. japonicus in axenic cultures. T. japonicus could not persist in axenic cultures, but its population increased when grown in synxenic cultures. T. japonicus used RT bacteria strain as a food source, while these bacteria were toxic to B. rotundiformis. These results suggest that bacteria can modify the interspecific relationship between B. rotundiformis and T. japonicus.     

A taxonomic Study of Species of Bothriocephalus Rudolphi, 1808 (Cestoda: Pseudophyllidea) from Eels in Japan: Morphological and Molecular Evidence for the Occurrence of B. claviceps (Goeze, 1782) and Confirmation of the Validity of B. Japonicus Yamaguti, 1934

A taxonomic study of specimens of Bothriocephalus from eels (Anguilla spp.) in Japan has demonstrated the occurrence of two species, B. claviceps (Goeze, 1782) and B. japonicus Yamaguti, 1934. The former species is a parasite of eels (A. anguilla and A. rostrata) in the Holarctic Region and was recently reported from A. marmorata in Japan. The conspecificity of tapeworms newly found in an eel (A. ? japonica) from Lake Biwa, central Japan, with B. claviceps has been confirmed by the great similarity of their ITS-2 gene sequences (similarity 95.3% and 95.2%). However, the sequences of worms identified as B. claviceps from A. marmorata differed considerably from those of B. claviceps from two populations of A. anguilla from Europe and the above-mentioned one from Japan (similarity 66.3%, 67.1% and 65.1 %, respectively), thus indicating that the former cestodes may have been misidentified. This assumption was confirmed by morphological evaluation of a voucher specimen from A. marmorata. The morphology of this cestode, as well as those from A. japonica from two localities in Japan (Lakes Biwa and Suwa), indicates their conspecificity with B. japonicus. The validity of this taxon has been confirmed on the basis of a re-examination of the type-specimens. The two taxa, B. japonicus and B. claviceps, differ from each other in the shape and length of the scolex (619–730 μm in B. japonicus versus 1,180–2,100 μm in B. claviceps), the relative position of the cirro-vaginal and uterine pores (opposite each other in relation to the median line of the body in B. japonicus versus tandem or slightly offset along the median line in the latter species), and the size of the eggs (41–52 × 28–35 μm in B. japonicus versus 50–70 × 31–43 μm in B. claviceps).

     

Squamatological differences between two closely related flatfish species of the genus <Emphasis Type="Italic">Pleuronichthys</Emphasis> (Pleuronectidae,Pleuronectiformes), with a proposal of unambiguous distinctive characters

Squamation and scale morphology were examined in two closely related species, Pleuronichthys cornutus and P. japonicus, in order to establish the unambiguous characters to clearly separate the two species. Scale counts on the lateral body surface were also examined, with new count definitions proposed. Both the longitudinal and vertical scale rows followed essentially regular patterns in P. cornutus, whereas the longitudinal scale rows were occasionally irregular in P. japonicus. Scales were basically fan-shaped and oval in P. cornutus and P. japonicus, respectively, although considerable variation in scale shape was apparent in both species. The blind side scales of P. cornutus had sharp posterior margins, whereas those of P. japonicus had round ones. Scale length (scales on the ocular side, area above the lateral line) in P. japonicus was relatively greater than in P. cornutus, a plot of total length versus scale length separating the species completely. Measurements of many ocular side scales from the area above the lateral line indicated high intraspecific variance in both species, being particularly prominent in P. cornutus. Nevertheless, considerable scale measurement differences were found between the two species in some body areas, supported by principal component analysis. Longitudinal and vertical row scale counts were higher in P. cornutus than in P. japonicus, with the ranges of central longitudinal scales (88–103 vs. 75–86) and scales below the lateral line counts (59–74 vs. 47–57), respectively, not overlapping between the species. The scale count difference could be caused by the difference of the scale size between the two species. The study demonstrated that the two Pleuronichthys species can be readily distinguished on the basis of scale morphology and size, in addition to scale counts.     

不同生境下川麦冬根围土壤丛枝菌根真菌多样性北大核心CSCD

采用高通量(Illumina Miseq)测序技术对栽培和野生2种生境下川麦冬根围的丛枝菌根(AM)真菌多样性和群落结构进行测定,并结合土壤理化因子进行相关性分析,以明确两种生境下川麦冬根围土壤AM真菌多样性和优势群落的分布特点,探讨AM真菌群落分布差异的驱动因子,为AM真菌应用于麦冬生产提供理论依据和技术支持。结果表明:(1)不同生境下川麦冬根围土壤中共鉴定出AM真菌3属10种,其中野生川麦冬根围土壤鉴定出的AM真菌3属7种,分别隶属于无梗囊霉属(Acaulospora)、多孢囊霉属(Diversispora)和球囊霉属(Glomus),而栽培环境下鉴定出AM真菌1属6种,隶属于球囊霉属。2个生境优势属均为球囊霉属。(2)不同生境下川麦冬根围AM真菌之间存在显著差异,野生生境下川麦冬根围土壤AM真菌多样性指数ACE和Shannon均显著高于人工栽培生境,而Simpson指数则相反。(3)相关性分析表明,AM真菌多样性指数及群落组成结构均与土壤理化因子存在相关性,其中全钾(TK)、全磷(TP)、全氮(TN)对AM真菌多样性指数和群落结构组成均存在显著影响。研究认为,不同生境下川麦冬根围AM真菌群落存在显著差异,球囊霉属为川麦冬互利共生的关键属,TK、TP、TN是不同生境川麦冬根围AM真菌群落差异的主要驱动因子。     

Seasonal occurrence and food habits of larvae and juveniles of two temperate basses in the Shimanto estuary,Japan

Larvae and juveniles ofLateolabrax japonicus andL. latus occurred from January to May 1986 in the shallow waters of the Shimanto estuary.L. japonicus markedly outnumberedL. latus. Distinct ecological differences were recognized in habitats and food habits between the two species:L. japonicus mainly inhabited eelgrass beds composed ofZostera nana, whileL. latus appeared evenly in both eelgrass beds and non-eelgrass habitats; the former fed on copepods and cladocerans, while the latter fed on copepods and fish larvae. From these habitat and food habit analyses, estuaries were considered to be important as a main habitat forL. japonicus, but not forL. latus. The fact that ecological differences have occurred during the early life stages was inferred to be one of the possible keys to speculate on the speciation of the two species.     

Length–weight and length–length relationships of eight fish species from Bohai Bay,China

Length–weight and length–length relationships (LWRs and LLRs) for eight fish species collected quarterly by trawl net in Bohai Bay, China, were estimated in a total of 1,395 specimens from 2012 to 2015. These were Pholis fangi, Setipinna taty, Engraulis japonicus, Larimichthys polyactis, Thryssa kammalensis, Scomberomorus niphonius, Johnius grypotus and Sardinella zunasi. The LWRs for the last two fish species are first reports for FishBase.     

Structure of ant assemblages on street trees in urban Busan,Korea

Street trees planted in urban areas are one of the smallest urban green habitats; however, their role as a valuable refuge for local biota is poorly understood. The aim of this study was to investigate urban street trees as habitat for ants. We found ants on 195 (92%) of 211 street trees studied. Seventeen ant species were collected from five tree species. The two most common ant species were Tetramorium tsushimae (on 112 trees) and Lasius japonicus (on 93 trees). The number of ant species found per tree ranged from 0 to 5, with a mean of 1.55 ± 0.92. The species composition differed significantly among tree species. Nine ant species (Camponotus vitiosus, Lasius alienus, L. japonicus, Nylanderia flavipes, Crematogaster matsumurai, Crematogaster vagula, Monomorium intrudens, T. tsushimae, and Brachyponera chinensis) nested on the trees, mostly in the root zone. Nests were found on 150 trees but were relatively rare on trees with diameter at breast height of less than 40 cm.     

The strepsipteran parasite <Emphasis Type="Italic">Elenchus japonicus</Emphasis> (Strepsiptera,Elenchidae) of planthoppers consists of three genotypes

The twisted-wing parasite Elenchus japonicus is a major parasitoid of rice planthoppers (Hemiptera: Delphacidae), including the brown planthopper Nilaparvata lugens, the white-backed planthopper Sogatella furcifera, and the small brown planthopper Laodelphax striatellus. Another Elenchus species, E. yasumatsui, which is considered to be synonymous with E. japonicus, has also been described in southern Asia. However, limited biological and molecular data on this important parasitoid of rice planthoppers are available. In this study, E. japonicas-stylopized planthoppers were obtained from various regions in Asia and Japan. Sequences of the nuclear 18S ribosomal RNA gene and the mitochondrial cytochrome oxidase I gene of the strepsipterans were analyzed from 40 samples of E. japonicus: 14 from N. lugens, 6 from S. furcifera and 20 from L. striatellus. Sequence analysis of these samples revealed three genotypes of E. japonicus. Of the three types of E. japonicus, one was isolated only from L. striatellus from northern Japan. The other two types were found in all three rice planthopper species collected from a wide area in Asia. These results suggest that the three different genotypes of Elenchus can be associated with a particular geographical region and/or planthopper species. The relationship between two previously described Elenchus species and the present three genotypes needs to be elucidated.     

Aquatic thermal conditions predict the presence of native and invasive rock pool Aedes (Diptera: Culicidae) in the southern Appalachians,U.S.A.

The native rock pool mosquito, Aedes atropalpus (Coquillett), and the invasive Aedes japonicus (Theobald) have been found in many types of artificial and natural containers throughout North America. Little is known about the ecology of these two species in habitats where they co‐occur, although multiple investigators have reported the decline of the native species concurrent with the introduction and spread of the invasive species. Here we report the results of riverine rock pool collections (n=503) in the southern Appalachian Mountains between 2009‐2015. Surface water temperatures strongly predicted the presence of each species across a broad range of observed temperatures (11‐39.8° C). For every unit of increase in temperature (°C) the odds of collecting Ae. atropalpus larvae increased by 0.34 while the odds of collecting Ae. japonicus larvae decreased by 0.28. No Ae. japonicus larvae or pupae were collected at temperatures greater than 36° C; however, immature Ae. atropalpus were found in rock pools with temperatures up to 39.8° C. In contrast, Ae. japonicus were highly abundant in cooler rock pools (<17° C) where Ae. atropalpus were infrequent or absent. Our findings suggest that in spite of the successful invasion by Ae. japonicus, Ae. atropalpus remains well established in the southern Appalachian Mountains. Given the strong correlation of temperature with the presence of the two species and the contrasting absence of each species at observed temperature extremes, the role of thermal conditions should be carefully explored in the context of other ecological factors likely influencing the range and abundance of these mosquitoes.     

Insights on the history of the scorched mussel Brachidontes rodriguezii (Bivalvia: Mytilidae) in the Southwest Atlantic: a geometric morphometrics perspective

Some authors support the idea that an important part of the Miocene marine mollusc fauna is still represented in the Argentinean Province. The fossil mollusc Brachidontes lepida (Philippi) is considered a subspecies of the extant B. rodriguezii (d?Orbigny), a taxon currently present in the Argentinean Biogeographic Province. The aim of this study is to investigate the shell shape relationship between B. lepida and B. rodriguezii using geometric morphometrics. Samples of B. rodriguezii (n = 63) from four localities distributed in Uruguay and Argentina, of B. lepida from the Paraná Formation (n = 26) and of two other extant Brachidontinae present in the region were included in this study. Canonical variate analyses showed that extant species differed in shell shape, with the discriminant function properly allocating 93% of the individuals to their respective species. Using the extant discriminant function, approximate 92% of B. lepida individuals were allocated to B. rodriguezii. This result suggests that B. lepida is more similar in shell shape to B. rodriguezii than to the other extant species present in the region. Considering the material from the Pliocene of Cerro Laciar and from the Pleistocene deposits of Buenos Aires and Bustamante, the presence of B. rodriguezii from the Late Miocene in the warm temperate region is discussed.     

Systematic revision of the living species of Bullidae (Mollusca: Gastropoda: Cephalaspidea), with a molecular phylogenetic analysis

Bullidae are a worldwide family of marine shelled cephalaspidean gastropods with a mainly tropical distribution, but also with some representatives in temperate waters. The taxonomy of the group has in the past been based only on shell characters, and the few anatomical accounts available have not addressed more than one to three species, so there has been no agreement about the number of valid species. Seventy‐two specific names and 16 varietal names have been proposed worldwide. The systematics of the family Bullidae are revised, based not only on shells but also on anatomy of all extant species and on DNA sequence data. Twelve species are recognized worldwide, including one new species here described, and all are assigned to the genus Bulla. Two species occur in the eastern Atlantic, B. striata and B. mabillei; two in the western Atlantic, B. occidentalis and B. solida; two in the eastern Pacific, B. gouldiana and B. punctulata; and six in the Indo‐West Pacific, B. ampulla, B. arabica sp. nov. , B. orientalis, B. peasiana, B. quoyii and B. vernicosa. Full synonymies and taxonomic histories are provided for each species. In order to promote taxonomic stability, neotypes are designated for B. striata, B. solida, B. nebulosa (valid name B. gouldiana) and B. vernicosa, and lectotypes for B. occidentalis, B. mabillei, B. punctulata, B. ampulla and B. quoyii. The type locality of B. ampulla is restricted to Mauritius. Bullidae show a general morphological stasis, with anatomy being very similar between species. However, there are high levels of intraspecific variability in the shell, radula and male genital system. In some cases species could only be separated based on molecular data . After defining the characters and geographical range of each species it became clear that sympatric species (a maximum of three) show distinctive shells and reproductive structures, which makes identification straightforward. This study employs an integrative approach, combining information on shells, anatomy, DNA and geographical distribution, in order to resolve the systematics of a difficult taxonomic group. © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 153 , 453–543.     

New trace fossils of termites (Insecta: Isoptera) from the late Eocene‐early Miocene of Egypt,and the reconstruction of ancient isopteran social behavior

Three new ichnogenera and five new ichnospecies are described for new trace fossils of termitaria (including associated gallery systems) of subterranean termites from upper Eocene through lower Miocene rocks of northern Egypt. All but two ichnospecies (Krausichnus trompitus, ichnogen, and ichnosp. nov., and A’, altus, ichnosp. nov.) show varying degrees of affinity to nests of the extant subterranean termite species Sphaerotermes sphaerothorax (Termitidae, Macro‐termitinae).

Termitichnus qatranii (Bown, 1982) is divided into two ichnospecies, the previously named T. qatranii, and a more generalized form, T. simplicidens, ichnosp. nov. Vondrichnus obovatus, ichnogen. and ichnosp. nov., is named for simple, possibly macrotermitine nests with oblate form, and Fleaglellius pagodus, ichnogen. and ichnosp. nov., records a nest form similar to V. obovatus, but one in which successive vertical growth by chamber apposition has produced a subterranean, tower‐like structure, reminiscent of that built by extant, epigeous Cubitermes. Krausichnus trompitus, ichnogen. and ichnosp. nov., and A’, altus, ichnosp. nov., record two unique nest architectures probably produced by unknown but related species of humivorous termites. The nest architecture expressed by Krausichnus is of wholly unknown affinity and is only distantly related in form to the ichnofossils of other termite nests known from the Tertiary of Egypt.

Study of the architecture of the nests of these ancient termites reveals details important in reconstructing the phylogeny of termite nests and documents two novel blueprints for chamber expansion and society budding in what were probably primitive Macrotermi‐tinae. It also indicates that at least two constructed edifices, earlier known only as epigeous manifestations of extant termite species, were almost certainly first developed by species living underground.

The extant Macrotermitinae are a subfamily of termites originally believed to have evolved in the post‐Eocene of the Ethiopian biogeo‐graphic region. We offer fossil evidence of four distinct, possibly macrotermitine structures from upper Eocene rocks. This evidence suggests that this termite subfamily (or at least their peculiar mode of nest construction) might have evolved considerably earlier, as it is already well established and exhibits several variants by the late Eocene in Egypt.     

Distribution of cephalopods in the upper epipelagic northwestern Bering Sea in autumn

In the northwestern Bering Sea in autumn, the epipelagic cephalopod community was represented by the boreal fauna, and was found to be composed of three families and nine species of the order Teuthida: Gonatidae (Berryteuthis magister, Boreoteuthis borealis, Gonatopsis japonicus, Gonatus madokai, Gonatus kamtschaticus, Gonatus onyx, and Gonatus pyros), Chiroteuthidae (Chiroteuthis calyx) and Onychoteuthidae (Onychoteuthis borealijaponica). Two pelagic gonatid species (B. borealis and G. kamtschaticus) dominated the cephalopod community in the upper 50 m. The distribution patterns of B. borealis and G. onyx were associated with diel vertical migrations of these squid. The distribution of two distinct size groups of G. kamtschaticus suggested ontogenetic migration of larger squid to deeper layers, and adds to previous data suggesting that this species may be a heterogeneous assemblage. Demersal B. magister rarely occurred in the surface waters. The occurrence of maturing O. borealijaponica in the southern marine area indicated that these were occasional seasonal migrants from the ocean. The occurrence of juvenile C. calyx suggested that these squid may conduct vertical forage migrations from deep waters to the surface layers.     

The complete mitochondrial genome sequence of the cutlassfish Trichiurus japonicus (Perciformes: Trichiuridae): Genome characterization and phylogenetic considerations

Mitochondrial genome sequence and structure analysis has become a powerful tool for studying molecular evolution and phylogenetic relationships. To understand the systematic status of Trichiurus japonicus in suborder Scombroidei, we determined the complete mitochondrial genome (mitogenome) sequence using the long-polymerase chain reaction (long-PCR) and shotgun sequencing method. The entire mitogenome is 16,796 bp in length and has three unusual features, including (1) the absence of tRNA^Pro gene, (2) the possibly nonfunctional light-strand replication origin (O_L) showing a shorter loop in secondary structure and no conserved motif (5'-GCCGG-3'), (3) two sets of the tandem repeats at the 5' and 3' ends of the control region. The three features seem common for Trichiurus mitogenomes, as we have confirmed them in other three T. japonicus individuals and in T. nanhaiensis. Phylogenetic analysis does not support the monophyly of Trichiuridae, which is against the morphological result. T. japonicus is most closely related to those species of family Scombridae; they in turn have a sister relationship with Perciformes members including suborders Acanthuroidei, Caproidei, Notothenioidei, Zoarcoidei, Trachinoidei, and some species of Labroidei, based on the current dataset of complete mitogenome. T. japonicus together with T. brevis, T. lepturus and Aphanopus carbo form a clade distinct from Lepidopus caudatus in terms of the complete Cyt b sequences. T. japonicus mitogenome, as the first discovered complete mitogenome of Trichiuridae, should provide important information on both genomics and phylogenetics of Trichiuridae.     

A chromosome-specific sequence common to the B genome of polyploid wheat and Aegilops searsii

A low-copy, non-coding chromosome-specific DNA sequence, isolated from common wheat, was physically mapped to the distal 19% region of the long arm of chromosome 3B (3BL) of common wheat. This sequence, designated WPG118, was then characterized by Southern hybridization, PCR amplification and sequence comparison using a large collection of polyploid wheats and diploid Triticum and Aegilops species. The data show that the sequence exists in all polyploid wheats containing the B genome and absent from those containing the G genome. At the diploid level, it exists only in Ae. searsii, a diploid species of section Sitopsis, and not in other diploids including Ae. speltoides, the closest extant relative to the donor of the B genome of polyploid wheat. This finding may support the hypothesis that the B-genome of polyploid wheat is of a polyphyletic origin, i.e. it is a recombined genome derived from two or more diploid Aegilops species.     

Within-plant vertical distributions of the scale insect Nipponaclerda biwakoensis and its five parasitoids that exhibit frequent successful multiparasitism on the common reed

Within‐shoot vertical distributions of the scale insect Nipponaclerda biwakoensis, five species of gregarious parasitoid wasps attacking the scale, and successful multiparasitism (emergence of multiple parasitoid species from a single host) by the parasitoids on the common reed were investigated. Each reed shoot collected was longer than 2.0 m, and was divided into pieces of 0.5 m each from the base of the shoot. The mean number of adult female scales per 0.5 m of shoot increased with height, but the mean rate of overall parasitism of the female scales decreased with height. The five parasitoids showed species‐specific within‐shoot distribution patterns, with respect to the rate of parasitism: Astymachus japonicus, Boucekiella depressa and Encyrtidae sp. 2 showed the greatest rates of parasitism at heights of 0–0.5, 0.5–1.0 and 1.0–1.5 m, respectively. The parasitism rate by Aprostocetus sp. was higher at the lower half of the shoots, whereas that by Encyrtidae sp. 1 was higher at the central positions. The distribution of the five parasitoids largely overlapped with each other at the level of scale aggregations. Nevertheless, successful multiparasitism occurred frequently only in several types of species combinations that involved two parasitoid species showing similar within‐shoot distribution patterns. The rate of successful multiparasitism by B. depressa with A. japonicus or Aprostocetus sp., and that by Encyrtidae sp. 2 with Encyrtidae sp. 1 was constantly high at different vertical positions on the shoots. This may be because B. depressa and Encyrtidae sp. 2 preferentially oviposit into scales previously parasitized by these other species.