Molecular Phylogeny and Surface Morphology of Thiriotia hyperdolphinae n. sp. and Cephaloidophora oradareae n. sp. (Gregarinasina,Apicomplexa) Isolated from a Deep Sea Oradarea sp. (Amphipoda) in the West Pacific

In an effort to broaden our understanding of the biodiversity and distribution of gregarines infecting crustaceans, this study describes two new species of gregarines, Thiriotia hyperdolphinae n. sp. and Cephaloidophora oradareae n. sp., parasitizing a deep sea amphipod (Oradarea sp.). Amphipods were collected using the ROV Hyper‐Dolphin at a depth of 855 m while on a cruise in Sagami Bay, Japan. Gregarine trophozoites and gamonts were isolated from the gut of the amphipod and studied with light and scanning electron microscopy, and phylogenetic analysis of 18S rDNA. Thiriotia hyperdolphinae n. sp. was distinguished from existing species based on morphology, phylogenetic position, as well as host niche and geographic locality. Cephaloidophora oradareae n. sp. distinguished itself from existing Cephaloidophora, based on a difference in host (Oradarea sp.), geographic location, and to a certain extent morphology. We established this latter new species with the understanding that a more comprehensive examination of diversity at the molecular level is necessary within Cephaloidophora. Results from the 18S rDNA molecular phylogeny showed that T. hyperdolphinae n. sp. was positioned within a clade consisting of Thiriotia spp., while C. oradareae n. sp. grouped within the Cephaloidophoridae. Still, supplemental genetic information from gregarines infecting crustaceans will be needed to better understand relationships within this group of apicomplexans.     

Tracking the elusive history of diversification in plant–herbivorous insect–parasitoid food webs: insights from figs and fig wasps

The food webs consisting of plants, herbivorous insects and their insect parasitoids are a major component of terrestrial biodiversity. They play a central role in the functioning of all terrestrial ecosystems, and the number of species involved is mind‐blowing (Nyman et al. 2015 ). Nevertheless, our understanding of the evolutionary and ecological determinants of their diversity is still in its infancy. In this issue of Molecular Ecology, Sutton et al. ( 2016 ) open a window into the comparative analysis of spatial genetic structuring in a set of comparable multitrophic models, involving highly species‐specific interactions: figs and fig wasps. This is the first study to compare genetic structure using population genetics tools in a fig‐pollinating wasp (Pleistodontes imperialis sp1) and its main parasitoid (Sycoscapter sp.A). The fig‐pollinating wasp has a discontinuous spatial distribution that correlates with genetic differentiation, while the parasitoid bridges the discontinuity by parasitizing other pollinator species on the same host fig tree and presents basically no spatial genetic structure. The full implications of these results for our general understanding of plant–herbivorous insect–insect parasitoids diversification become apparent when envisioned within the framework of recent advances in fig and fig wasp biology.     

Morphology and phylogenetic position of two novel marine gregarines (Apicomplexa,Eugregarinorida) from the intestines of North‐eastern Pacific ascidians

Eugregarine apicomplexans parasitize marine, freshwater and terrestrial invertebrates, and have lifecycles involving trophozoites (feeding stages) with complex morphologies and behaviour. The genus Lankesteria refers to marine aseptate eugregarines that parasitize ascidians. We described the surface ultrastructure of two new gregarine species, L. chelyosomae sp. n. and L. cystodytae sp. n. that inhabit the intestines of Chelyosoma columbianum and Cystodytes lobatus, respectively, collected from the North‐eastern Pacific Ocean. Apart from inhabiting different hosts and major differences in the cell size of L. chelyosomae sp. n. (mean length 182 µm) and L. cystodytae sp. n. (mean length 70 µm), the morphology of both gregarine species was quite similar. The trophozoites ranged from elliptoid to obdeltoid in shape and were brownish in colour. The nucleus was situated at the anterior end of the cell just behind a pointed mucron. A dense array of epicytic knobs was present over the entire surface of trophozoites in both species, and longitudinal epicytical folds were only weakly developed. We also sequenced the small subunit rDNA from the gregarines collected from both hosts, which supported the establishment of two new Lankesteria species. Phylogenetic analyses of the new DNA sequences and those derived from other alveolates, demonstrated that both new species clustered in a strongly supported clade consisting of other Lankesteria species, Lecudina species, and some environmental sequences. These morphological and molecular phylogenetic data suggested that improved knowledge of gregarine diversity could lead to the recognition of more than one distinct clade (genus) of gregarines within ascidian hosts.     

Molecular Phylogeny and Ultrastructure of Caliculium glossobalani n. gen. et sp. (Apicomplexa) from a Pacific Glossobalanus minutus (Hemichordata) Confounds the Relationships Between Marine and Terrestrial Gregarines

Gregarines are a diverse group of apicomplexan parasites with a conspicuous extracellular feeding stage, called a “trophozoite”, that infects the intestines and other body cavities of invertebrate hosts. Although the morphology of trophozoites is very diverse in gregarines as a whole, high degrees of intraspecific variation combined with relatively low degrees of interspecific variation make the delimitation of different species based on trophozoite morphology observed with light microscopy difficult. The coupling of molecular phylogenetic data with comparative morphology has shed considerable light onto the boundaries and interrelationships of different gregarine species. In this study, we isolated a novel marine gregarine from the hepatic region of a Pacific representative of the hemichordate Glossobalanus minutus, and report the first ultrastructural and molecular data from any gregarine infecting this distinctive group of hosts. Molecular phylogenetic analyses of an SSU rDNA sequence derived from two single‐cell isolates of this marine gregarine demonstrated a strong and unexpected affiliation with a clade of terrestrial gregarines (e.g. Gregarina). This molecular phylogenetic data combined with a comparison of the morphological features in previous reports of gregarines collected from Atlantic representatives of G. minutus justified the establishment of a new binomial for the new isolate, namely Caliculium glossobalani n. gen. et sp. The molecular phylogenetic analyses demonstrated a clade of terrestrial gregarines associated with a sequence acquired from a marine species, which suggest that different groups of terrestrial/freshwater gregarines evolved independently from marine ancestors.     

Four New Members of Foliicolous Green Algae Within the Watanabea Clade (Trebouxiophyceae,Chlorophyta) from China

Members of the Watanabea clade of Trebouxiophyceae are genetically diverse and widely distributed in all kinds of habitats, especially in most terrestrial habitats. Ten new strains of terrestrial algae isolated from the tropical rainforest in China, and four published strains were investigated in this study. Morphological observation and molecular phylogenetic analyses based on the 18S, ITS, rbcL, and tufA genes were used to identify the new strains. Four previously described species were reinvestigated to supplement molecular data and autospores’ morphological photographs. The phylogenetic analyses based on 18S only, the concatenated dataset of 18S and ITS, as well as the concatenated dataset of rbcL and tufA, showed the same phylogenetic positions and relationships of these new strains. According to the phylogenetic analysis and morphological comparisons results, we described these 10 strains as four new members within the Watanabea clade, Polulichloris yunnanensis sp. nov., Polulichloris ovale sp. nov., Massjukichlorella orientale sp. nov., and Massjukichlorella minus sp. nov., and two known species, Massjukichlorella epiphytica, and Mysteriochloris nanningensis. Additionally, we provide strong evidence proving that Phyllosiphon, Mysteriochloris, Polulichloris, and Desertella all reproduce through unequal sized autospores.     

Evolution and diversity of Arsenophonus endosymbionts in aphids

Endosymbiotic bacteria are important drivers of insect evolutionary ecology, acting both as partners that contribute to host adaptation and as subtle parasites that manipulate host reproduction. Among them, the genus Arsenophonus is emerging as one of the most widespread lineages. Its biology is, however, entirely unknown in most cases, and it is therefore unclear how infections spread through insect populations. Here we examine the incidence and evolutionary history of Arsenophonus in aphid populations from 86 species, characterizing the processes that shape their diversity. We identify aphids as harbouring an important diversity of Arsenophonus strains. Present in 7% of the sampled species, incidence was especially high in the Aphis genus with more than 31% of the infected species. Phylogenetic investigations revealed that these Arseno‐phonus strains do not cluster within an aphid‐specific clade but rather exhibit distinct evolutionary origins showing that they undergo repeated horizontal transfers (HT) between distantly related host species. Their diversity pattern strongly suggests that ecological interactions, such as plant mediation and parasitism, are major drivers for Arsenophonus dispersal, dictating global incidence across insect communities. Notably, plants hosting aphids may be important ecological arenas for global exchange of Arsenophonus, serving as reservoirs for HT.     

Diet strongly influences the gut microbiota of surgeonfishes

Intestinal tracts are among the most densely populated microbial ecosystems. Gut microbiota and their influence on the host have been well characterized in terrestrial vertebrates but much less so in fish. This is especially true for coral reef fishes, which are among the most abundant groups of vertebrates on earth. Surgeonfishes (family: Acanthuridae) are part of a large and diverse family of reef fish that display a wide range of feeding behaviours, which in turn has a strong impact on the reef ecology. Here, we studied the composition of the gut microbiota of nine surgeonfish and three nonsurgeonfish species from the Red Sea. High‐throughput pyrosequencing results showed that members of the phylum Firmicutes, especially of the genus Epulopiscium, were dominant in the gut microbiota of seven surgeonfishes. Even so, there were large inter‐ and intraspecies differences in the diversity of surgeonfish microbiota. Replicates of the same host species shared only a small number of operational taxonomic units (OTUs), although these accounted for most of the sequences. There was a statistically significant correlation between the phylogeny of the host and their gut microbiota, but the two were not completely congruent. Notably, the gut microbiota of three nonsurgeonfish species clustered with some surgeonfish species. The microbiota of the macro‐ and microalgavores was distinct, while the microbiota of the others (carnivores, omnivores and detritivores) seemed to be transient and dynamic. Despite some anomalies, both host phylogeny and diet were important drivers for the intestinal microbial community structure of surgeonfishes from the Red Sea.     

Taking insight into the gut microbiota of three spider species: No characteristic symbiont was found corresponding to the special feeding style of spiders

Microorganisms in insect guts have been recognized as having a great impact on their hosts' nutrition, health, and behavior. Spiders are important natural enemies of pests, and the composition of the gut microbiota of spiders remains unclear. Will the bacterial taxa in spiders be same as the bacterial taxa in insects, and what are the potential functions of the gut bacteria in spiders? To gain insight into the composition of the gut bacteria in spiders and their potential function, we collected three spider species, Pardosa laura, Pardosa astrigera, and Nurscia albofasciata, in the field, and high‐throughput sequencing of the 16S rRNA V3 and V4 regions was used to investigate the diversity of gut microbiota across the three spider species. A total of 23 phyla and 150 families were identified in these three spider species. The dominant bacterial phylum across all samples was Proteobacteria. Burkholderia, Ralstonia, Ochrobactrum, Providencia, Acinetobacter, Proteus, and Rhodoplanes were the dominant genera in the guts of the three spider species. The relative abundances of Wolbachia and Rickettsiella detected in N. albofasciata were significantly higher than those in the other two spider species. The relative abundance of Thermus, Amycolatopsis, Lactococcus, Acinetobacter Microbacterium, and Koribacter detected in spider gut was different among the three spider species. Biomolecular interaction networks indicated that the microbiota in the guts had complex interactions. The results of this study also suggested that at the genus level, some of the gut bacteria taxa in the three spider species were the same as the bacteria in insect guts.     

Welcome back Janolidae and Antiopella: Improving the understanding of Janolidae and Madrellidae (Cladobranchia,Heterobranchia) with description of four new species

Proctonotidae and Madrellidae are families that belong to the suborder Cladobranchia. Historically, both have been the subjects of taxonomic confusion. Thus, Proctonotidae Gray, 1853, was subsequently named as Zephyrinidae Iredale and O'Donoghue, 1923 and Janolidae Pruvot‐Fol, 1933, but currently both are considered as synonyms of Proctonotidae. On the other hand, Alder and Hancock (1864) erected the genus Madrella in Proctonotidae. Here, we completed a detailed morphological and molecular study of four apparently undescribed species of Madrellidae and Proctonotidae from the Indo‐Pacific. We performed a maximum likelihood and Bayesian inference phylogenetic analyses using two mitochondrial and one nuclear genes to improve the understanding of the families. Prompted by our results, Janolidae is removed from synonymy with Proctonotidae. Within Janolidae, there are two well‐supported clades. One includes species with smooth cerata that are found in the Atlantic and eastern Pacific Oceans. The taxa in this clade include the type species of Antiopella and several other species. We resurrect Antiopella as the valid name for this clade. The sister clade to Antiopella includes a variety of taxa with species that have been traditionally included in Janolus Bergh, 1884 and Bonisa Gosliner, 1981. Further systematic revision requires more comprehensive taxon sampling. The new species discovered have clear morphological differences and strong molecular support. They include Madrella amphora Pola and Gosliner sp. nov. , Janolus tricellariodes Pola and Gosliner sp. nov. , Janolus flavoanulatus Pola and Gosliner sp. nov., and Janolus incrustans Pola and Gosliner sp. nov.     

Histories of host shifts and cospeciation among free‐living parasitoids of Rhagoletis flies

Host shifts by specialist insects can lead to reproductive isolation between insect populations that use different hosts, promoting diversification. When both a phytophagous insect and its ancestrally associated parasitoid shift to the same novel host plant, they may cospeciate. However, because adult parasitoids are free living, they can also colonize novel host insects and diversify independent of their ancestral host insect. Although shifts of parasitoids to new insect hosts have been documented in ecological time, the long‐term importance of such shifts to parasitoid diversity has not been evaluated. We used a genus of flies with a history of speciation via host shifting (Rhagoletis [Diptera: Tephritidae]) and three associated hymenopteran parasitoid genera (Diachasma, Coptera and Utetes) to examine cophylogenetic relationships between parasitoids and their host insects. We inferred phylogenies of Rhagoletis, Diachasma, Coptera and Utetes and used distance‐based cophylogenetic methods (ParaFit and PACo) to assess congruence between fly and parasitoid trees. We used an event‐based method with a free‐living parasitoid cost model to reconstruct cophylogenetic histories of each parasitoid genus and Rhagoletis. We found that the current species diversity and host–parasitoid associations between the Rhagoletis flies and parasitoids are the primary result of ancient cospeciation events. Parasitoid shifts to ancestrally unrelated hosts primarily occur near the branch tips, suggesting that host shifts contribute to recent parasitoid species diversity but that these lineages may not persist over longer time periods. Our analyses also stress the importance of biologically informed cost models when investigating the coevolutionary histories of hosts and free‐living parasitoids.     

Can infection by eugregarine parasites mediate species coexistence in Calopteryx damselflies?

1. Parasitism may be an important factor determining the coexistence of closely related species. Although host–parasite interactions can affect the ecology and distribution of the host species, virtually nothing is known about how other interspecific interactions affecting the host, such as competition or predation, relate to the parasite burden of the host. 2. We studied parasite‐mediated competition between two closely related Calopteryx damselflies, C. virgo L. and C. splendens Harris. We investigated a total of 31 populations, including 18 allopatric and 13 sympatric populations. We measured the occurrence of gut parasites, eugregarines. 3. We found that the prevalence of gregarines was higher in C. virgo than in C. splendens. On average, more than half of the C. virgo individuals were infected by eugregarines both in allopatric and sympatric populations. However, hardly any allopatric C. splendens populations had gregarines, but most of sympatric populations had infected individuals. 4. According to our results, co‐existence of the host species affects the likelihood of the subordinate species showing higher levels of parasitism. Interspecific aggression, lower species genetic heterozygosity, and the difference in host species immunity are proposed as possible explanations for greater parasite burdens in the inferior species at sympatric sites.     

High Prevalence and Endemism of Trypanosomatids on a Small Caribbean Island

We describe the monoxenous trypanosomatids parasitizing true bugs and flies on the island of Curaçao. Out of 248 examined true bugs belonging to 17 species, 93 individuals were found to be infected (overall 38% prevalence) by at least one trypanosomatid species (referred to as typing units; TUs). Out of 80 flies, six were infected. All detected trypanosomatids were compared based on their 18S rRNA sequences with TUs parasitizing bugs and flies described from mainland South America, allowing us to assess their diversity and distribution. Besides Leptomonas pyrrhocoris and Leptomonas seymouri, two known species of the subfamily Leishmaniinae, our analysis revealed six new TUs falling into the groups ‘jaculum’, Blastocrithidia and Herpetomonas. Moreover, two new members of the genus Phytomonas and three new TUs belonging to the monophyletic group designated as ‘new clade II’ sensu Mol. Phylogenet. Evol, 69, 255 (2013) were isolated. The detected trypanosomatids were characterized by moderate diversity (13 TUs) species richness. Out of nine and four TUs from the heteropteran and dipteran hosts, respectively, 11 TUs have not been encountered before. Although a sampling bias may partially affect the comparison between trypanosomatid communities on Curaçao and the mainland, the high proportion of unique TUs from the former location suggests that the prominent role of islands in increasing the global diversity of macroscopic organisms may also extend to their protistan parasites.     

Similarities and spatial variations of bacterial and fungal communities in field rice planthopper (Hemiptera: Delphacidae) populations

Rice planthoppers are notorious plant sap‐feeding pests which cause serious damage. While several microbes in rice planthoppers have been broadly characterized, the abundance and diversity of bacteria and fungi in field planthoppers are largely unknown. This study investigated the bacterial and fungal community compositions of Chinese wild rice planthoppers Laodelphax striatellus and Sogatella furcifera using parallel 16S rRNA gene amplicon and internal transcribed space region sequencing. The bacteria varied significantly between the species and were partitioned significantly by sex, tissues and host environments in each species. The majority of bacteria were affiliated with the genera Wolbachia, Cardinium, Rickettsia and Pantoea. The abundance of Wolbachia was negatively correlated with that of Cardinium in both planthopper species. Compared with bacteria, the abundance and diversity of fungi did not differ between sexes but both were enriched in the gut. The bacterial community as a whole showed no significant correlation with the fungal community. The majority of fungi were related to Sarocladium, Alternaria, Malassezia, Aspergillus and Curvularia. A phylogenetic analysis revealed that these fungi were closely related to botanic symbionts or pathogens. Our results provide novel insights into the bacteria and fungi of rice planthoppers.     

Morphological and Molecular Description of Three New Species of the Cyrtophorid Genus Chlamydodon (Ciliophora,Cyrtophoria)

This study investigates the morphology and molecular characteristics of three new cyrtophorid ciliates isolated from China seas: Chlamydodon salinus n. sp., Chlamydodon caudatus n. sp., and Chlamydodon paramnemosyne n. sp. Of these, C. salinus n. sp. differs from its congeners through a combination of body size, a cross‐striated band that is not continuous, the presence of 30–34 somatic kineties, 11–15 nematodesmal rods, and 13 contractile vacuoles. Chlamydodon caudatus n. sp., meanwhile, is characterized by having a conspicuous tail, a continuous cross‐striated band, 34–40 somatic kineties, about 15 contractile vacuoles, and 20–24 nematodesmal rods. Compared with other Chlamydodon species, the third new one, C. paramnemosyne n. sp., could be identified by its continuous cross‐striated band, 16–18 somatic kineties, 5 contractile vacuoles, and 9–12 nematodesmal rods. Based on the sequence of the small subunit (SSU) rRNA gene, the phylogeny of these three new species was analyzed, indicating that they all clustered with other congeners to form a monophyletic assemblage. Based on previous studies and the present work, a brief revision of the genus Chlamydodon is supplied, and a key to aid the identification of Chlamydodon species is given.     

A polyphasic approach to the study of the genus Nitzschia (Bacillariophyta): three new planktonic species from the Adriatic Sea

The paraphyletic diatom genus Nitzschia comprises over 1000 morphologically distinct pennate taxa, known from the benthos and plankton of freshwater, brackish, and marine environments. The principal diagnostic characters for delimitation of Nitzschia species include valve shape, the position and structure of the raphe, presence/absence and shape of the proximal raphe endings and terminal raphe fissures, areola structure, and specific morphometric features such as cell size, and stria and fibula density. In this study, we isolated 12 diatom strains into culture from samples collected at the surface or greater depths of the southeastern Adriatic Sea. Morphological analyses included LM, SEM, and TEM observations, which, along with specific morphometric features, allowed us to distinguish three new Nitzschia species. These findings were congruent with the results of phylogenetic analyses performed on nuclear‐encoded SSU (18S) rDNA and chloroplast‐encoded rbcL and psbC genes. One of the new species (Nitzschia dalmatica sp. nov.) formed a lineage within a clade of Bacillariaceae containing members of the Nitzschia sect. Dubiae, which was sister to Psammodictyon. A second lineage was part of a novel clade that is significantly distinct from other Nitzschia species sequenced so far and includes Nitzschia adhaerens sp. nov. and N. cf. adhaerens. A further new species was found, Nitzschia inordinata sp. nov., which appeared as the sister group to the N. adhaerens clade and the conopeoid Nitzschia species in our phylogenetic trees. Our findings contribute to the overall diversity of genus Nitzschia, especially in identifying some deep branches within the Bacillariaceae, and highlight under‐scoring of this genus in marine plankton.     

Cochliopodium arabianum n. sp. (Amorphea,Amoebozoa)

A new species of Cochliopodium isolated from freshwater at Arabia Lake in Lithonia, GA, USA is described based on light microscopic morphology, fine structure, and molecular genetic evidence. Cochliopodium arabianum n. sp., previously labeled as “isolate Con1” in prior publications, has been shown to group within the genus Cochliopodium in our molecular phylogenetic analysis. Light microscopy and fine structure evidence indicates the new isolate not only shares characters of the genus but also unique distinctive features. Cochliopodium arabianum n. sp. is typically round when stationary; or oval to sometimes broadly flabellate or triangular in shape during locomotion, with average length of 35 μm and breadth of 51 μm. Fine structure evidence indicates C. arabianum n. sp. has tower‐like scales, lacking a terminal spine, sharing high similarity with its closest relative C. actinophorum. However, the scales of C. arabianum n. sp. are unique in height and the breadth of the base plate. Both morphological and molecular data, including SSU‐rDNA and COI, indicate that this new species falls in a clade sufficiently different from other species to suggest that it is a valid new species.     

Snake evolution in Melanesia: origin of the Hydrophiinae (Serpentes,Elapidae), and the evolutionary history of the enigmatic New Guinean elapid Toxicocalamus

The venomous snake subfamily Hydrophiinae includes more than 40 genera and approximately 200 species. Most members of this clade inhabit Australia, and have been well studied. But, because of poor taxon sampling of Melanesian taxa, basal evolutionary relationships have remained poorly resolved. The Melanesian genera Ogmodon, Loveridgelaps, and Salomonelaps have not been included in recent phylogenetic studies, and the New Guinean endemic, Toxicocalamus, has been poorly sampled and sometimes recovered as polyphyletic. We generated a multilocus phylogeny for the subfamily using three mitochondrial and four nuclear loci so as to investigate relationships among the basal hydrophiine genera and to determine the status of Toxicocalamus. We sequenced these loci for eight of the 12 described species within Toxicocalamus, representing the largest molecular data set for this genus. We found that a system of offshore island arcs in Melanesia was the centre of origin for terrestrial species of Hydrophiinae, and we recovered Toxicocalamus as monophyletic. Toxicocalamus demonstrates high genetic and morphological diversity, but some of the molecular diversity is not accompanied by diagnostic morphological change. We document at least five undescribed species that all key morphologically to Toxicocalamus loriae (Boulenger, 1898), rendering this species polyphyletic. Continued work on Toxicocalamus is needed to document the diversity of this genus, and is likely to result in the discovery of additional species. Our increased taxon sampling allowed us to better understand the evolution and biogeography of Hydrophiinae; however, several unsampled lineages remain, the later study of which may be used to test our biogeographic hypothesis.