New data from the Middle Jurassic of China shed light on the phylogeny and origin of the proboscis in the Mesopsychidae (Insecta: Mecoptera)

The global significance of Scleractinian corals without photoendosymbiosis

Globally tropical Scleractinian corals have been a focal point for discussions on the impact of a changing climate on marine ecosystems and biodiversity. Research into tropical Scleractinian corals, particularly the role and breakdown of photoendosymbiosis in response to warming, has been prolific in recent decades. However, research into their subtropical, temperate, cold- and deep-water counterparts, whose number is dominated by corals without photoendosymbiosis, has not been as prolific. Approximately 50% of Scleractinian corals (> 700 species) do not maintain photoendosymbiosis and as such, do not rely upon the products of photosynthesis for homeostasis. Some species also have variable partnerships with photendosymbionts depending on life history and ecological niche. Here we undertake a systematic map of literature on Scleractinian corals without, or with variable, photoendosymbiosis. In doing so we identify 482 publications spanning 5 decades. In mapping research effort, we find publications have been sporadic over time, predominately focusing on a limited number of species, with greater research effort directed towards deep-water species. We find only 141 species have been studied, with approximately 30% of the total identified research effort directed toward a single species, Desmophyllum pertusum, highlighting significant knowledge gaps into Scleractinian diversity. We find similar limitations to studied locations, with 78 identified from the global data, of which only few represent most research outputs. We also identified inconsistencies with terminology used to describe Scleractinia without photoendosymbiosis, likely contributing to difficulties in accounting for their role and contribution to marine ecosystems. We propose that the terminology requires re-evaluation to allow further systematic assessment of literature, and to ensure it's consistent with changes implemented for photoendosymbiotic corals. Finally, we find that knowledge gaps identified over 20 years ago are still present for most aphotoendosymbiotic Scleractinian species, and we show data deficiencies remain regarding their function, biodiversity and the impacts of anthropogenic stressors.

Cold-water coral energy reserves and calcification in contrasting fjord environments

The relationship between energy reserves of cold-water corals (CWCs) and their physiological performance remains largely unknown. In addition, it is poorly understood how the energy allocation to different metabolic processes might change with projected decreasing food supply to the deep sea in the future. This study explores the temporal and spatial variations of total energy reserves (proteins, carbohydrates and lipids) of the CWC Desmophyllum dianthus and their correlation with its calcification rate. We took advantage of distinct horizontal and vertical physico-chemical gradients in Comau Fjord (Chile) and examined the changes in energy reserves over one year in an in situ reciprocal transplantation experiment (20 m vs. 300 m and fjord head vs. mouth). Total energy reserves correlated positively with calcification rates. The fast-growing deep corals had higher and less variable energy reserves, while the slower-growing shallow corals showed pronounced seasonal changes in energy reserves. Novel deep corals (transplanted from shallow) were able to quickly increase both their calcification rates and energy reserves to similar levels as native deep corals. Our study shows the importance of energy reserves in sustaining CWC growth in spite of aragonite undersaturated conditions (deep corals) in the present, and potentially also future ocean.

Repeat mediated excision of gene drive elements for restoring wild-type populations

We demonstrate here that single strand annealing (SSA) repair can be co-opted for the precise autocatalytic excision of a drive element. Although SSA is not the predominant form of DNA repair in eukaryotic organisms, we increased the likelihood of its use by engineering direct repeats at sites flanking the drive allele, and then introducing a double-strand DNA break (DSB) at a second endonuclease target site encoded within the drive allele. We have termed this technology Re peat M ediated E xcision of a D rive E lement (ReMEDE). Incorporation of ReMEDE into the previously described mutagenic chain reaction (MCR) gene drive, targeting the yellow gene of Drosophila melanogaster , replaced drive alleles with wild-type alleles demonstrating proof-of-principle. Although the ReMEDE system requires further research and development, the technology has a number of attractive features as a gene drive mitigation strategy, chief among these the potential to restore a wild-type population without releasing additional transgenic organisms or large-scale environmental engineering efforts.

A new species of Notiobiella Banks, 1909 from China (Neuroptera, Hemerobiidae), with a key to Chinese species

Background

Notiobiella Banks, 1909 is a green-coloured genus of brown lacewing (Hemerobiidae) that is widely distributed in Central and South America, Africa, southeast Asia, Australia and some south-western Pacific islands. There are approximately 49 species of this genus worldwide, with 10 species recorded from China, including one new species that is described in this paper.

New information

In this paper, we describe a new species, Notiobiellamaculosa sp. n. of the genus Notiobiella Banks, 1909 from Yunnan Province. The morphological characters of the adults are described in detail and illustrated. A key for identification of adults is also provided. All specimens have been deposited in the Entomological Museum of China Agricultural University (CAU), Beijing.

Local-scale feedbacks influencing cold-water coral growth and subsequent reef formation

Despite cold-water coral (CWC) reefs being considered biodiversity hotspots, very little is known about the main processes driving their morphological development. Indeed, there is a considerable knowledge gap in quantitative experimental studies that help understand the interaction between reef morphology, near-bed hydrodynamics, coral growth, and (food) particle transport processes. In the present study, we performed a 2-month long flume experiment in which living coral nubbins were placed on a reef patch to determine the effect of a unidirectional flow on the growth and physiological condition of Lophelia pertusa. Measurements revealed how the presence of coral framework increased current speed and turbulence above the frontal part of the reef patch, while conditions immediately behind it were characterised by an almost stagnant flow and reduced turbulence. Owing to the higher current speeds that likely promoted a higher food encounter rate and intake of ions involved in the calcification process, the coral nubbins located on the upstream part of the reef presented a significantly enhanced average growth and a lower expression of stress-related enzymes than the downstream ones. Yet, further experiments would be needed to fully quantify how the variations in water hydrodynamics modify particle encounter and ion intake rates by coral nubbins located in different parts of a reef, and how such discrepancies may ultimately affect coral growth. Nonetheless, the results acquired here denote that a reef influenced by a unidirectional water flow would grow into the current: a pattern of reef development that coincides with that of actual coral reefs located in similar water flow settings. Ultimately, the results of this study suggest that at the local scale coral reef morphology has a direct effect on coral growth thus, indicating that the spatial patterns of living CWC colonies in reef patches are the result of spatial self-organisation.

Thermal adaptation best explains Bergmann's and Allen's Rules across ecologically diverse shorebirds

Bergmann’s and Allen’s rules state that endotherms should be larger and have shorter appendages in cooler climates. However, the drivers of these rules are not clear. Both rules could be explained by adaptation for improved thermoregulation, including plastic responses to temperature in early life. Non-thermal explanations are also plausible as climate impacts other factors that influence size and shape, including starvation risk, predation risk, and foraging ecology. We assess the potential drivers of Bergmann’s and Allen’s rules in 30 shorebird species using extensive field data (>200,000 observations). We show birds in hot, tropical northern Australia have longer bills and smaller bodies than conspecifics in temperate, southern Australia, conforming with both ecogeographical rules. This pattern is consistent across ecologically diverse species, including migratory birds that spend early life in the Arctic. Our findings best support the hypothesis that thermoregulatory adaptation to warm climates drives latitudinal patterns in shorebird size and shape.

Global patterns in animal size and shape have been long observed, but their underlying drivers are not well understood. Here the authors suggest latitudinal patterns in shorebird size and shape are best explained by thermal adaptation to warm climates.

A framework for integrating inferred movement behavior into disease risk models

Movement behavior is an important contributor to habitat selection and its incorporation in disease risk models has been somewhat neglected. The habitat preferences of host individuals affect their probability of exposure to pathogens. If preference behavior can be incorporated in ecological niche models (ENMs) when data on pathogen distributions are available, then variation in such behavior may dramatically impact exposure risk. Here we use data from the anthrax endemic system of Etosha National Park, Namibia, to demonstrate how integrating inferred movement behavior alters the construction of disease risk maps. We used a Maximum Entropy (MaxEnt) model that associated soil, bioclimatic, and vegetation variables with the best available pathogen presence data collected at anthrax carcass sites to map areas of most likely Bacillus anthracis (the causative bacterium of anthrax) persistence. We then used a hidden Markov model (HMM) to distinguish foraging and non-foraging behavioral states along the movement tracks of nine zebra (Equus quagga) during the 2009 and 2010 anthrax seasons. The resulting tracks, decomposed on the basis of the inferred behavioral state, formed the basis of step-selection functions (SSFs) that used the MaxEnt output as a potential predictor variable. Our analyses revealed different risks of exposure during different zebra behavioral states, which were obscured when the full movement tracks were analyzed without consideration of the underlying behavioral states of individuals. Pathogen (or vector) distribution models may be misleading with regard to the actual risk faced by host animal populations when specific behavioral states are not explicitly accounted for in selection analyses. To more accurately evaluate exposure risk, especially in the case of environmentally transmitted pathogens, selection functions could be built for each identified behavioral state and then used to assess the comparative exposure risk across relevant states. The scale of data collection and analysis, however, introduces complexities and limitations for consideration when interpreting results.

Two new species of Itaphlebia (Insecta, Mecoptera, Nannochoristidae) from the late Middle Jurassic of China

Two new species of Itaphlebia Sukatsheva, 1985, I.procera sp. nov. and I.elegana sp. nov., are described and illustrated from the latest Middle Jurassic Jiulongshan Formation of Daohugou, Inner Mongolia, China. Based on fossil specimens with wings, these new species are established and assigned to Itaphlebia by a combination of three forewing characters: Sc with three branches ending at C, the four-branched Rs (R₂ to R₅) originating distad of M (vs. three-branched RS (R₂₊₃ undivided) in all other fossil and extant nannochoristids), and M forking with four branches; and a hind wing character of Sc simple and short, terminating at C well before the pterostigma. Furthermore, this is the first report of long and robust setae present on the anal veins of the forewing for I.elegana sp. nov. in fossil Nannochoristidae.

Multiple long-range host shifts of major Wolbachia supergroups infecting arthropods

Wolbachia is a genus of intracellular bacterial endosymbionts found in 20–66% of all insect species and a range of other invertebrates. It is classified as a single species, Wolbachia pipientis, divided into supergroups A to U, with supergroups A and B infecting arthropods exclusively. Wolbachia is transmitted mainly via vertical transmission through female oocytes, but can also be transmitted across different taxa by host shift (HS): the direct transmission of Wolbachia cells between organisms without involving vertically transmitted gametic cells. To assess the HS contribution, we recovered 50 orthologous genes from over 1000 Wolbachia genomes, reconstructed their phylogeny and calculated gene similarity. Of 15 supergroup A Wolbachia lineages, 10 have similarities ranging from 95 to 99.9%, while their hosts’ similarities are around 60 to 80%. For supergroup B, four out of eight lineages, which infect diverse and distantly-related organisms such as Acari, Hemiptera and Diptera, showed similarities from 93 to 97%. These results show that Wolbachia genomes have a much higher similarity when compared to their hosts’ genes, which is a major indicator of HS. Our comparative genomic analysis suggests that, at least for supergroups A and B, HS is more frequent than expected, occurring even between distantly-related species.

A Simulation Study of the Ecological Speciation Conditions in the Galician Marine Snail Littorina saxatilis

In the last years, the interest in evolutionary divergence at small spatial scales has increased and so did the study of speciation caused by ecologically based divergent natural selection. The evolutionary interplay between gene flow and local adaptation can lead to low-dispersal locally adapted specialists. When this occurs, the evolutionary interplay between gene flow and local adaptation could eventually lead to speciation. The L. saxatilis system consists of two ecotypes displaying a microhabitat-associated intraspecific dimorphism along the wave-exposed rocky shores of Galicia. Despite being a well-known system, the dynamics of the ecotype formation remain unclear and cannot be studied from empirical evidence alone. In this study, individual-based simulations were used to incorporate relevant ecological, spatial, and genetic information, to check different evolutionary scenarios that could evolve non-random mating preferences and finally may facilitate speciation. As main results, we observed the evolution of intermediate values of choice which matches the estimates from empirical data of L. saxatilis in Galician shores and coincides with previous theoretical outcomes. Also, the use of the mating correlation as a proxy for assortative mating led to spuriously inferring greater reproductive isolation in the middle habitat than in the others, which does not happen when directly considering the choice values from the simulations. We also corroborate the well-known fact that the occurrence of speciation is influenced by the strength of selection. Taken together, this means, also according to other L. saxatilis systems, that speciation is not an immediate consequence of local divergent selection and mating preferences, but a fine tuning among several factors including the ecological conditions in the shore levels, the selection strength, the mate choice stringency, and cost to choosiness. The L. saxatilis system could correspond to a case of incomplete reproductive isolation, where the choice intensity is intermediate and local adaptation within the habitat is strong. These results support previous interpretations of the L. saxatilis model system and indicate that further empirical studies would be interesting to test whether the mate choice mechanism functions as a similarity-like mechanism as has been shown in other littorinids.

Relationships between male secondary sexual traits, physiological state and offspring viability in the three-spined stickleback

BACKGROUND

Sexual signals produced by males play a central role in sexual selection, but the relationship between these traits and the quality of the bearer are often ambiguous. Secondary sexual traits may represent genetic quality of the bearer, resulting in positive relationships with physiological state, or may be costly to produce, showing trade-off with physiological state. A number of studies have explored the relationships between secondary sexual traits and other functional traits, but few have studied their fitness consequences. We studied the link between diverse physiological traits and both morphological and behavioural sexual traits and examined how their interplay influences offspring viability in the three-spined stickleback.

RESULTS

Male sticklebacks showing nest building and courtship behaviour were smaller than those not investing in reproductive activities. There was no evidence that the expression of red nuptial colouration and the quality of courtship behaviour of males are positively related to their metabolic rates, swim ability, oxidative damage and mtDNA copy number. However, individuals showing larger red nuptial colour areas had higher levels of oxidative DNA damage in their sperm. Male courtship behaviour and aggressiveness, but not red colour area, were good predictors of offspring hatching and survival.

CONCLUSIONS

Our results suggest that, in our study population at the southern edge of the species' distribution, sexual colouration of male sticklebacks was not a good indicator of their body state, but both courtship quality and aggressiveness during the courtship are reliable cues of their gamete quality, influencing the viability of their offspring. Thus, females that choose mates based on their courtship behaviour will have high fitness. In the study population, which represents a fast pace-of-life with high reproductive rate and short lifespan, sexual ornaments of males may not honestly signal their physiological and physical state because they invest at maximum in a single reproductive season despite high costs.

Detailed morphology of tentacular apparatus and central nervous system in Owenia borealis (Annelida, Oweniidae)

The Oweniidae are marine annelids with many unusual features of organ system, development, morphology, and ultrastructure. Together with magelonids, oweniids have been placed within the Palaeoannelida, a sister group to all remaining annelids. The study of this group may increase our understanding of the early evolution of annelids (including their radiation and diversification). In the current research, the morphology and ulta-anatomy of the head region of Owenia borealis is studied by scanning electron microscopy (SEM), 3D reconstructions, transmission electron microscopy (TEM), and whole-mount immunostaining with confocal laser scanning microscopy. According to SEM, the tentacle apparatus consists of 8-14 branched arms, which are covered by monociliary cells that form a ciliary groove extending along the oral side of the arm base. Each tentacle contains a coelomic cavity with a network of blood capillaries. Monociliary myoepithelial cells of the tentacle coelomic cavity form both the longitudinal and the transverse muscles. The structure of this myoepithelium is intermediate between a simple and pseudo-stratified myoepithelium. Overall, tentacles lack prominent zonality, i.e., co-localization of ciliary zones, neurite bundles, and muscles. This organization, which indicates a non-specialized tentacle crown in O. borealis and other oweniids with tentacles, may be ancestral for annelids. TEM, light, and confocal laser scanning microscopy revealed that the head region contains the anterior nerve center comprising of outer and inner (=circumoral) nerve rings. Both nerve rings are organized as concentrated nerve plexus, which contains perikarya and neurites extending between basal projections of epithelial cells (radial glia). The outer nerve ring gives rise to several thick neurite bundles, which branch and extend along aboral side of each tentacle. Accordingly to their immunoreactivity, both rings of the anterior nerve center could be homologized with the dorsal roots of circumesophageal connectives of the typical annelids. Accordingly to its ultrastructure, the outer nerve ring of O. borealis and so-called brain of other oweniids can not be regarded as a typical brain, i.e. the most anterior ganglion, because it lacks ganglionic structure.

The integrative taxonomy of Beauveria asiatica and B. bassiana species complexes with whole-genome sequencing, morphometric and chemical analyses

Fungi are rich in complexes of cryptic species that need a combination of different approaches to be delimited, including genomic information. Beauveria (Cordycipitaceae, Hypocreales) is a well-known genus of entomopathogenic fungi, used as a biocontrol agent. In this study we present a polyphasic taxonomy regarding two widely distributed complexes of Beauveria: B. asiatica and B. bassiana s.lat. Some of the genetic groups as previously detected within both taxa were either confirmed or fused using population genomics. High levels of divergence were found between two clades in B. asiatica and among three clades in B. bassiana, supporting their subdivision as distinct species. Morphological examination focusing on the width and the length of phialides and conidia showed no difference among the clades within B. bassiana while conidial length was significantly different among clades within B. asiatica. The secondary metabolite profiles obtained by liquid chromatography-mass spectrometry (LC-MS) allowed a distinction between B. asiatica and B. bassiana, but not between the clades therein. Based on these genomic, morphological, chemical data, we proposed a clade of B. asiatica as a new species, named B. thailandica, and two clades of B. bassiana to respectively represent B. namnaoensis and B. neobassiana spp. nov. Such closely related but divergent species with different host ranges have potential to elucidate the evolution of host specificity, with potential biocontrol application. Citation: Kobmoo N, Arnamnart N, Pootakham W, et al. 2021. The integrative taxonomy of Beauveria asiatica and B. bassiana species complexes with whole-genome sequencing, morphometric and chemical analyses. Persoonia 47: 136-150. https://doi.org/10.3767/persoonia.2021.47.04.

Jurassic scorpionflies (Mecoptera) with swollen first metatarsal segments suggesting sexual dimorphism

BACKGROUND

Sexual dimorphism is widespread in insects. The certain specialized structures may be used as weapons in male-male combats or as ornaments to enhance mating opportunities.

RESULTS

We report striking swollen first tarsal segments in two families, four genera and six species of scorpionflies from the Middle Jurassic Yanliao Biota of Northeastern China. Swollen tarsal segments are restricted to male specimens and to hind leg tarsi. The geometric morphometric analyses reveal that the degree of swelling within the orthophlebiid species possessing swollen first metatarsal segments is species-specific, which can be used as a diagnostic character for taxonomic and phylogenetic studies.

CONCLUSIONS

The new findings indicate that swollen first metatarsal segments are relatively common in the family Orthophlebiidae during the Middle Jurassic. The tarsal swellings are considered to be sexually dimorphic, potentially associated with sexually display by males and/or camouflage of a "nuptial gift" in the mating process.

Cranial osteology of the Early Cretaceous turtle Pleurosternon bullockii (Paracryptodira: Pleurosternidae)

Pleurosternon bullockii is a turtle from the Early Cretaceous of Europe known from numerous postcranial remains. Only one skull has so far been referred to the species. Pleurosternon bullockii belongs to a group of turtles called pleurosternids, which is thought to include several poorly known taxa from the Late Jurassic and Early Cretaceous of Europe and North America. Pleurosternids and baenids, a group of North American turtles that lived from the Late Cretaceous to the Eocene, define a clade called Paracryptodira. Additionally, Paracryptodira likely includes compsemydids, and, potentially, helochelydrids. Character support for Paracryptodira is relatively weak, and many global phylogenetic studies fail to support paracryptodiran monophyly altogether. Proposed paracryptodiran synapomorphies are largely cranial, despite the poor characterization of pleurosternid cranial material. In addition to their questionable monophyly, the global position of paracryptodires is debated. Early studies suggest crown-turtle affinities, but most phylogenies find them as stem-turtles, irrespective of their monophyly. Here, we document the cranial osteology of Pleurosternon bullockii with the use of three-dimensional models derived from segmenting high-resolution X-ray micro-computed tomography (CT) scans. Pleurosternon bullockii has a primitive basipterygoid region of the skull, but a cryptodire-like acustico-jugular region. A surprising number of similarities with pleurodires exist, particularly in the laterally expanded external process of the pterygoid and in the posterior orbital wall. Our observations constitute an important step toward a phylogenetic re-evaluation of Paracryptodira.

Mouthpart homologies and life habits of Mesozoic long-proboscid scorpionflies

Mesozoic long-proboscid scorpionflies (Mesopsychoidea) provide important clues to ancient plant-pollinator interactions. Among them, the family Aneuretopsychidae is especially important because its mouthparts are vital to deciphering the early evolution of Mesopsychoidea and putatively the origin of fleas (Siphonaptera). However, the identification of mouthpart homologs among Aneuretopsychidae remains controversial because of the lack of three-dimensional anatomical data. Here, we report the first Aneuretopsychidae from Late Cretaceous Burmese amber, which have short maxillary palpi and elongate mouthpart elements consisting of one pair of galeae and one hypopharynx. Their mouthparts are identical to those of Pseudopolycentropodidae (= Dualulidae, new synonym) but are not homologous to those of Siphonaptera. Our phylogenetic analysis provides robust evidence for the debated monophyly of Mesopsychoidea. Our results suggest that the long-proboscid condition has most likely evolved once in Mesopsychoidea, independently from fleas, and further reveal the variety and complexity of mid-Cretaceous pollinating insects.

Does the frontal sensory organ in adults of the hoplonemertean Quasitetrastemma stimpsoni originate from the larval apical organ?

BACKGROUND

The apical organ is the most prominent neural structure in spiralian larvae. Although it has been thoroughly investigated in larvae of the class Pilidiophora in phylum Nemertea, studies on its structure in other nemertean larvae are limited. Most adult hoplonemertean worms have a frontal organ located in a position corresponding to that of the larval apical organ. The development and sensory function of the frontal organ has not been thoroughly characterized to date.

RESULTS

The apical organ in the early rudiment stage of Quasitetrastemma stimpsoni larvae consists of an apical plate enclosed by ducts of frontal gland cells and eight apical neurons. The apical plate is abundantly innervated by neurites of apical neurons. During the late rudiment stage, the larval apical organ has external innervation from below by two subapical-plate neurons, along with 11 apical neurons, and its plate contains serotonin-like immunoreactive (5-HT-lir) cells. In the vermicular stage (free-swimming juvenile), the number of apical neurons is reduced, and their processes are resorbed. Serotonin is detected in the apical plate with no visible connection to apical neurons. In adult worms, the frontal organ has a small apical pit with openings for the frontal gland ducts. The organ consists of 8 to 10 densely packed 5-HT-lir cells that form the roundish pit.

CONCLUSIONS

Although the ultrastructure of the Q. stimpsoni larval apical organ closely resembles that of the apical organ of Polycladida larvae, the former differs in the presence of flask-shaped neurons typical of Spiralia. Significant differences in the structure of the apical organs of hoplonemertean and pilidia larvae point to two different paths in the evolutionary transformation of the ancestral apical organ. Ultrastructural and immunoreactive analyses of the apical organ of a hoplonemertean larva in the late rudiment and vermicular stages and the frontal organ of the adult worms identified common morphological and functional features. Thus, we hypothesize that the larval apical organ is modified during morphogenesis to form the adult frontal organ, which fulfills a sensory function in the hoplonemertean worm. This unique developmental trait distinguishes the Hoplonemertea from other nemertean groups.

Climatic niche comparison across a cryptic species complex

According to current molecular evidence, the Chionaspis pinifoliae heterophyllae species complex has been recognized as 10 cryptic species. In this study, we construct potential distribution maps for seven cryptic species based on climatic variables. This was done to assess the main environmental factors that have contributed to the distribution map and test the degree of niche overlap across the seven cryptic species. We used MaxEnt to build the climatic niche models under climatic variables. For these models, the similarities and differences of the niches across the cryptic species were estimated. By comparing the potential distribution model of each cryptic species, our results suggested parapatric, sympatric and allopatry populations for this cryptic species complex. Our results showed high variability in niche overlap, and more often niche conservatism than niche divergence. The current species delimitation of the Chionaspis pinifoliae heterophyllae complex by molecular information and the hypothesis that the niche overlap in the sympatric population is higher than that of the allopatry population were supported based on the findings. This study will provide baseline data and a distribution range to facilitate the further control of these insects and formulate quarantine measures.

Life habits and evolutionary biology of new two-winged long-proboscid scorpionflies from mid-Cretaceous Myanmar amber

Long-proboscid scorpionflies are enigmatic, mid-Mesozoic insects associated with gymnosperm pollination. One major lineage, Aneuretopsychina, consists of four families plus two haustellate clades, Diptera and Siphonaptera. One clade, Pseudopolycentropodidae, from mid-Cretaceous Myanmar amber, contains Parapolycentropus. Here, we newly establish Dualula, assigned to Dualulidae, constituting the fifth lineage. Parapolycentropus and Dualula lineages are small, two-winged, with unique siphonate mouthparts for imbibing pollination drops. A cibarial pump provides siphonal food inflow; in Dualula, the siphon base surrounds a hypopharynx housing a small, valved pump constricted to a narrow salivary duct supplying outgoing enzymes for food fluidization. Indirect evidence links long-proboscid mouthpart structure with contemporaneous tubulate ovulate organs. Direct evidence of gymnospermous Cycadopites pollen is associated with one Parapolycentropus specimen. Parapolycentropus and Dualula exhibit hind-wing reduction that would precede haltere formation, likely caused by Ultrabithorax. Distinctive, male Aneuretopsychina genitalia are evident from specimens in copulo, supplemented by mixed-sex individuals of likely male mating swarms.

Long-proboscid scorpionflies were associated with mid-Mesozoic gymnosperm pollination. Here, Lin et al. establish a new family of long-proboscid scorpionflies from Myanmar amber, elucidate evolutionary mechanisms of hind-wing reduction, and detail feeding and reproductive habits of these insects.

"Noah's Ark" Project: Interim Results and Outlook for Classic Collection Development

The "Noah's Ark" project, afoot at M.V. Lomonosov Moscow State University since 2015 and aimed at studying biodiversity, is the largest ongoing Russian project in life sciences. During its implementation, several hundred new species have been described; a comprehensive genetic and biochemical characterization of these species, as well as that of the pre-existing specimens in Moscow University's collections, has been performed. A consolidated IT system intended to house the knowledge generated by the project has been developed. Here, we summarize the investigations around the Moscow University classical biocollections which have taken place within the framework of the project and discuss future promise and the outlook for these collections.

Genomic signature of highland adaptation in fish: a case study in Tibetan Schizothoracinae species

Background

Genome-wide studies on highland adaptation mechanism in terrestrial animal have been widely reported with few available for aquatic animals. Tibetan Schizothoracinae species are ideal model systems to study speciation and adaptation of fish. The Schizothoracine fish, Gymnocypris przewalskii ganzihonensis had underwent the ecological niche shift from salt water to freshwater, and also experienced a recent split from Gymnocypris przewalskii przewalskii. In addition, G. p. ganzihonensis inhabited harsh aquatic environment including low temperature and hypoxia as well as other Schizothoracinae species, its genetic mechanism of highland adaptation have yet to be determined.

Results

Our study used comparative genomic analysis based on the transcriptomic data of G. p. ganzihonensis and other four fish genome datasets to investigate the genetic basis of highland adaptation in Schizothoracine fish. We found that Schizothoracine fish lineage on the terminal branch had an elevated dN/dS ratio than its ancestral branch. A total of 202 gene ontology (GO) categories involved into transport, energy metabolism and immune response had accelerated evolutionary rates than zebrafish. Interestingly, we also identified 162 genes showing signature of positive selection (PSG) involved into energy metabolism, transport and immune response in G. p. ganzihonesis. While, we failed to find any PSG related to hypoxia response as previous studies.

Conclusions

Comparative genomic analysis based on G. p. ganzihonensis transcriptome data revealed significant genomic signature of accelerated evolution ongoing within Tibetan Schizothoracinae species lineage. Molecular evolution analysis suggested that genes involved in energy metabolism, transport and immune response functions in Schizothoracine fish underwent positive selection, especially in innate immunity including toll-like receptor signaling pathway genes. Taken together, our result as a case study in Schizothoracinae species provides novel insights in understanding the aquatic animal adaptation to extreme environment on the Tibetan Plateau, and also provides valuable genomic resource for further functional verification studies.

Electronic supplementary material

The online version of this article (10.1186/s12864-017-4352-8) contains supplementary material, which is available to authorized users.

Expression of G Proteins in the Eyes and Parietovisceral Ganglion of the Bay Scallop Argopecten irradians

A multitude of image-forming eyes are spread across the bodies of certain invertebrates. Recent efforts have characterized how these eyes function, but less progress has been made toward describing the neural structures associated with them. Scallops, for example, have a distributed visual system that includes dozens of eyes whose optic nerves project to the lateral lobes of the parietovisceral ganglion (PVG). To identify sensory receptors and chemical synapses associated with the scallop visual system, we studied the expression of four G protein α subunits (Gα_i, Gα_o, Gα_q, and Gα_s) in the eyes and PVG of the bay scallop Argopecten irradians (Lamarck, 1819). In the eyes of A. irradians, we noted expression of Gα_o by the ciliary photoreceptors of the distal retina, expression of Gα_q by the rhabdomeric photoreceptors of the proximal retina, and the expression of Gα_o and Gα_q by the cells of the cornea; we did not, however, detect expression of Gα_i or Gα_s in the eyes. In the PVG of A. irradians, we noted widespread expression of Gα_i, Gα_o, and Gα_q. The expression of Gα_s was limited to fine neurites in the lateral and ventral central lobes, as well as large unipolar neurons in the dorsal central lobes. Our findings suggest that light detection by the eyes of A. irradians is conferred primarily by photoreceptors that express Gα_o or Gα_q, that the corneal cells of scallops may contain sensory receptors and/or receive neural input, and that G protein labeling is useful for visualizing substructures and identifying specific populations of cells within the nervous systems of invertebrates.

Regulation of sub-compartmental targeting and folding properties of the Prion-like protein Shadoo

Shadoo (Sho), a member of prion protein family, has been shown to prevent embryonic lethality in Prnp^0/0 mice and to be reduced in the brains of rodents with terminal prion diseases. Sho can also affect PrP structural dynamics and can increase the prion conversion into its misfolded isoform (PrP^Sc), which is amyloidogenic and strictly related to expression, intracellular localization and association of PrP^C to lipid rafts. We reasoned that if Sho possesses a natural tendency to convert to amyloid-like forms in vitro, it should be able to exhibit “prion-like” properties, such as PK-resistance and aggregation state, also in live cells. We tested this hypothesis, by different approaches in neuronal cells, finding that Sho shows folding properties partially dependent on lipid rafts integrity whose alteration, as well as proteasomal block, regulated generation of intermediate Sho isoforms and exacerbated its misfolding. Moreover, a 18 kDa isoform of Sho, likely bearing the signal peptide, was targeted to mitochondria by interacting with the molecular chaperone TRAP1 which, in turn controlled Sho dual targeting to ER or mitochondria. Our studies contribute to understand the role of molecular chaperones and of PrP-related folding intermediates in “prion-like” conversion.

Comparative analysis of the mitochondrial genomes of Colletotrichum gloeosporioides sensu lato: insights into the evolution of a fungal species complex interacting with diverse plants

BACKGROUND

The fungal species complex Colletotrichum gloeosporioides sensu lato contains over 20 plant-interacting species. These species exhibit different life styles (e.g., endophytes, foliar and fruit pathogens) and show considerable variation in host and tissue adaptation strategies. Accurate species delimitation in C. gloeosporioides s.l. is very challenging due to nascent lineage boundaries and phenotypic plasticity, which strongly impedes studies of the complex's host-interaction biology. In this study, we first sequenced and compared nine mitogenomes belonging to four C. gloeosporioides s.l. species lineages (C. gloeosporioides, C. fructicola, C. aenigma, and C. siamense s.l.), and evaluated the usefulness of mitogenome sequence in complementing prevailing nuclear markers for species delimitation.

RESULTS

The C. gloeosporioides s.l. mitogenomes ranged between 52,671 and 58,666 bp in size, and each contained an identical set of genes transcribed in the same direction. Compared with previously reported Colletotrichum mitogenomes, these mitogenomes were uniquely featured by: (1) significantly larger genome size due to richer intron content and longer intergenic region; (2) striking GC content elevation at the intergenic region; and (3) considerable intron content variation among different species lineages. Compared with nuclear DNA markers commonly used in phylogeny, the mitogenome nucleotide diversity was extremely low, yet the mitogenome alignment contained the highest number of parsimony informative sites, which allowed the generation of a high-resolution phylogeny recognizing all taxonomic lineages, including ones belonging to the very nascent C. siamense s.l. complex. The tree topology was highly congruent with the phylogeny based on nuclear marker concatenation except for lineages within C. siamense s.l. Further comparative phylogenetic analysis indicated that lineage-specific rapid divergence of GS and SOD2 markers confounded concatenation-based species relationship inference.

CONCLUSIONS

This study sheds light on the evolution of C. gloeosporioides s.l. mitogenomes and demonstrates that mitogenome sequence can complement prevailing nuclear markers in improving species delimitation accuracy. The mitogenome sequences reported will be valuable resources for further genetic studies with C. gloeosporioides s.l. and other Colletotrichum species.

The evolution of genital complexity and mating rates in sexually size dimorphic spiders

Background

Genital diversity may arise through sexual conflict over polyandry, where male genital features function to manipulate female mating frequency against her interest. Correlated genital evolution across animal groups is consistent with this view, but a link between genital complexity and mating rates remains to be established. In sexually size dimorphic spiders, golden orbweaving spiders (Nephilidae) males mutilate their genitals to form genital plugs, but these plugs do not always prevent female polyandry. In a comparative framework, we test whether male and female genital complexity coevolve, and how these morphologies, as well as sexual cannibalism, relate to the evolution of mating systems.

Results

Using a combination of comparative tests, we show that male genital complexity negatively correlates with female mating rates, and that levels of sexual cannibalism negatively correlate with male mating rates. We also confirm a positive correlation between male and female genital complexity. The macroevolutionary trajectory is consistent with a repeated evolution from polyandry to monandry coinciding with the evolution towards more complex male genitals.

Conclusions

These results are consistent with the predictions from sexual conflict theory, although sexual conflict may not be the only mechanism responsible for the evolution of genital complexity and mating systems. Nevertheless, our comparative evidence suggests that in golden orbweavers, male genital complexity limits female mating rates, and sexual cannibalism by females coincides with monogyny.

Electronic supplementary material

The online version of this article (doi:10.1186/s12862-016-0821-y) contains supplementary material, which is available to authorized users.

Convergent evolution of ramified antennae in insect lineages from the Early Cretaceous of Northeastern China

Antennae are important, insect sensory organs that are used principally for communication with other insects and the detection of environmental cues. Some insects independently evolved ramified (branched) antennae, which house several types of sensilla for motion detection, sensing olfactory and chemical cues, and determining humidity and temperature levels. Though ramified antennae are common in living insects, occasionally they are present in the Mesozoic fossil record. Here, we present the first caddisflies with ramified antennae, the earliest known fossil sawfly, and a scorpionfly also with ramified antennae from the mid-Lower Cretaceous Yixian Formation of Northeastern China, dated at 125 million years ago (Ma). These three insect taxa with ramified antennae consist of three unrelated lineages and provide evidence for broad structural convergence that historically has been best demonstrated by features such as convergent mouthparts. In addition, ramified antennae in these Mid-Mesozoic lineages likely do not constitute a key innovation, as they are not associated with significantly increased diversification compared with closely related lineages lacking this trait, and nor are they ecologically isolated from numerous, co-occurring insect species with unmodified antennae.

Preservation and phylogeny of Cambrian ecdysozoans tested by experimental decay of Priapulus

The exceptionally preserved Cambrian fossil record provides unique insight into the early evolutionary history of animals. Understanding of the mechanisms of exceptional soft tissue preservation frames all interpretations of the fauna and its evolutionary significance. This is especially true for recent interpretations of preserved nervous tissues in fossil ecdysozoans. However, models of soft tissue preservation lack empirical support from actualistic studies. Here experimental decay of the priapulid Priapulus reveal consistent bias towards rapid loss of internal non-cuticular anatomy compared with recalcitrant cuticular anatomy. This is consistent with models of Burgess Shale-type preservation and indicates that internal tissues are unlikely to be preserved with fidelity if organically preserved. This pattern, along with extreme body margin distortion, is consistent with onychophoran decay, and is therefore resolved as general for early ecdysozoans. Application of these patterns to phylogenetic data finds scalidophoran taxa to be very sensitive to taphonomically informed character coding, but not panarthropodan taxa. Priapulid decay also have unexpected relevance for interpretation of myomeres in fossil chordates. The decay data presented serve not only as a test of models of preservation but also a framework with which to interpret ecdysozoan fossil anatomies, and the subsequent evolutionary inferences drawn from them.