• Evaluation of DNA barcode libraries used in the UK and developing an action plan to fill priority gaps

      Price, BW; Briscoe, AG; Misra, Raju; Broad, G (Natural England, 2020-10)
      There are approximately 76,000 eukaryote species recognised in the UK, and while we know some of them in great detail, the majority of these species are poorly known, and hundreds of new species are discovered each year. DNA barcoding uses a short, standardised segment of an organism’s genome for identification by comparison to a reference library; however, the UK lags behind several countries in Europe and North America in that we lack trusted, reliable and openly accessible reference sequences for key UK taxa. This report is the first step in rectifying this by engaging diverse stakeholders to facilitate collaboration and coordination; providing robust stakeholder-based and independent assessment of the current state of reference libraries available for all known UK taxa; and prioritising key taxa. A survey was developed and shared with the UK research and end user community, receiving 80 responses from a wide range of stakeholders and covering the focal taxa / assemblages and habitats; the DNA reference libraries in use, their quality assurance and perceived coverage. A formal gap analysis of the public DNA data in major DNA reference libraries highlighted that an estimated 52% of UK species have publicly available DNA data of some sort; however, coverage in gene specific reference libraries varies greatly (eg 2 – 52%), as does the associated quality assurance. Priority taxa highlighted by end users had coverage in reference libraries ranging from almost complete, in the case of known invasive non-native species, to significant coverage (71%) for taxa with conservation designations. However, these data also vary by kingdom and reference library, as does the associated quality assurance. If taking a strict requirement of DNA data provided by UK specimens and held in UK repositories, for robust QC and QA, then the proportion of UK species with public DNA data in reference libraries falls to less than 4% in the largest reference library assessed (BOLD). While standard genes for DNA-based identification have essentially been established, more work is required to establish the priority taxa required for regulatory delivery in contrast to taxa that are surveyed in a non-regulatory framework. Several barriers to the development of barcode libraries were highlighted, the most relevant being sustained large scale funding, expertise, capacity, laboratory skills and equipment, quality control and assurance, collecting logistics (eg permits and access) and communication. Significant opportunities identified include a large network of interested experts, several organisations with significant delivery capabilities, current large-scale projects and funding opportunities, emerging technologies and the economy of scale for DNA sequencing. Following a stakeholder workshop, we have outlined a concise action plan to provide reliable, open access reference sequences, linked to open access vouchers, identified by known experts, to facilitate UK academic and regulatory aims.
    • Evidence of Vent-Adaptation in Sponges Living at the Periphery of Hydrothermal Vent Environments: Ecological and Evolutionary Implications

      Georgieva, MN; Taboada, Sergio; Riesgo, A; Díez-Vives, C; De Leo, FC; Jeffreys, RM; Copley, JT; Little, Crispin; Ríos, P; Cristobo, J; et al. (Frontiers Media SA, 2020-07-24)
      The peripheral areas of deep-sea hydrothermal vents are often inhabited by an assemblage of animals distinct to those living close to vent chimneys. For many such taxa, it is considered that peak abundances in the vent periphery relate to the availability of hard substrate as well as the increased concentrations of organic matter generated at vents, compared to background areas. However, the peripheries of vents are less well-studied than the assemblages of vent-endemic taxa, and the mechanisms through which peripheral fauna may benefit from vent environments are generally unknown. Understanding this is crucial for evaluating the sphere of influence of hydrothermal vents and managing the impacts of future human activity within these environments, as well as offering insights into the processes of metazoan adaptation to vents. In this study, we explored the evolutionary histories, microbiomes and nutritional sources of two distantly-related sponge types living at the periphery of active hydrothermal vents in two different geological settings (Cladorhiza from the E2 vent site on the East Scotia Ridge, Southern Ocean, and Spinularia from the Endeavour vent site on the Juan de Fuca Ridge, North-East Pacific) to examine their relationship to nearby venting. Our results uncovered a close sister relationship between the majority of our E2 Cladorhiza specimens and the species Cladorhiza methanophila, known to harbor and obtain nutrition from methanotrophic symbionts at cold seeps. Our microbiome analyses demonstrated that both E2 Cladorhiza and Endeavour Spinularia sp. are associated with putative chemosynthetic Gammaproteobacteria, including Thioglobaceae (present in both sponge types) and Methylomonaceae (present in Spinularia sp.). These bacteria are closely related to chemoautotrophic symbionts of bathymodiolin mussels. Both vent-peripheral sponges demonstrate carbon and nitrogen isotopic signatures consistent with contributions to nutrition from chemosynthesis. This study expands the number of known associations between metazoans and potentially chemosynthetic Gammaproteobacteria, indicating that they can be incredibly widespread and also occur away from the immediate vicinity of chemosynthetic environments in the vent-periphery, where these sponges may be adapted to benefit from dispersed vent fluids.
    • Evolution Is Linear: Debunking Life's Little Joke

      Jenner, RA (Wiley, 2017-12-16)
      Linear depictions of the evolutionary process are ubiquitous in popular culture, but linear evolutionary imagery is strongly rejected by scientists who argue that evolution branches. This point is frequently illustrated by saying that we didn't evolve from monkeys, but that we are related to them as collateral relatives. Yet, we did evolve from monkeys, but our monkey ancestors are extinct, not extant. Influential voices, such as the late Stephen Jay Gould, have misled audiences for decades by falsely portraying the linear and branching aspects of evolution to be in conflict, and by failing to distinguish between the legitimate linearity of evolutionary descent, and the branching relationships among collateral relatives that result when lineages of ancestors diverge. The purpose of this article is to correct the widespread misplaced rejection of linear evolutionary imagery, and to re‐emphasize the basic truth that the evolutionary process is fundamentally linear.
    • Evolution of reproductive strategies in the species-rich land snail subfamily Phaedusinae (Stylommatophora: Clausiliidae)

      Mamos, Tomasz; Uit de Weerd, Dennis; von Oheimb, Parm Viktor; Sulikowska-Drozd, Anna (Elsevier, 2020-12-28)
      Most of the present knowledge on animal reproductive mode evolution, and possible factors driving transitions between oviparity and viviparity is based on studies on vertebrates. The species rich door snail (Clausiliidae) subfamily Phaedusinae represents a suitable and unique model for further examining parity evolution, as three different strategies, oviparity, viviparity, and the intermediate mode of embryo-retention, occur in this group. The present study reconstructs the evolution of reproductive strategies in Phaedusinae based on time-calibrated molecular phylogenetics, reproductive mode examinations and ancestral state reconstruction. Our phylogenetic analysis employing multiple mitochondrial and nuclear markers identified a well-supported clade (including the tribes Phaedusini and Serrulinini) that contains species exhibiting various reproductive strategies. This clade evolved from an oviparous most recent common ancestor according to our reconstruction. All non-oviparous taxa are confined to a highly supported subclade, coinciding with the tribe Phaedusini. Both oviparity and viviparity occur frequently in different lineages of this subclade that are not closely related. During Phaedusini diversification, multiple transitions in reproductive strategy must have taken place, which could have been promoted by a high fitness of embryo-retaining species. The evolutionary success of this group might result from the maintenance of various strategies.
    • Evolutionary Analysis of Mitogenomes from Parasitic and Free-Living Flatworms

      Solà, E; Álvarez-Presas, M; Frías-López, C; Littlewood, T; Rozas, J; Riutort, M; Escriva, H (2015-03-20)
    • Evolutionary Ecology of Fish Venom: Adaptations and Consequences of Evolving a Venom System.

      Harris, RJ; Jenner, RA (MDPI, 2019-01-22)
      Research on venomous animals has mainly focused on the molecular, biochemical, and pharmacological aspects of venom toxins. However, it is the relatively neglected broader study of evolutionary ecology that is crucial for understanding the biological relevance of venom systems. As fish have convergently evolved venom systems multiple times, it makes them ideal organisms to investigate the evolutionary ecology of venom on a broader scale. This review outlines what is known about how fish venom systems evolved as a result of natural enemy interactions and about the ecological consequences of evolving a venom system. This review will show how research on the evolutionary ecology of venom in fish can aid in understanding the evolutionary ecology of animal venoms more generally. Further, understanding these broad ecological questions can shed more light on the other areas of toxinology, with applications across multiple disciplinary fields.
    • Evolutionary history of the Galápagos Rail revealed by ancient mitogenomes and modern samples

      Chaves, Jaime A; Martinez-Torres, Pedro J; Depino, Emiliano A; Espinoza-Ulloa, Sebastian; García-Loor, Jefferson; Beichman, Annabel; Stervander, Martin (MDPI, 2020-11-12)
      The biotas of the Galápagos Islands are one of the best studied island systems and have provided a broad model for insular species’ origins and evolution. Nevertheless, some locally endemic taxa, such as the Galápagos Rail Laterallus spilonota, remain poorly characterized. Owing to its elusive behavior, cryptic plumage, and restricted distribution, the Galápagos Rail is one of the least studied endemic vertebrates of the Galapagos Islands. To date, there is no genetic data for this species, leaving its origins, relationships to other taxa, and levels of genetic diversity uncharacterized. This lack of information is critical given the adverse fate of island rail species around the world in the recent past. Here, we examine the genetics of Galápagos Rails using a combination of mitogenome de novo assembly with multilocus nuclear and mitochondrial sequencing from both modern and historical samples. We show that the Galápagos Rail is part of the “American black rail clade”, sister to the Black Rail L. jamaicensis, with a colonization of Galápagos dated to 1.2 million years ago. A separate analysis of one nuclear and two mitochondrial markers in the larger population samples demonstrates a shallow population structure across the islands, possibly due to elevated island connectivity. Additionally, birds from the island Pinta possessed the lowest levels of genetic diversity, possibly reflecting past population bottlenecks associated with overgrazing of their habitat by invasive goats. The modern and historical data presented here highlight the low genetic diversity in this endemic rail species and provide useful information to guide conservation efforts.
    • Evolutionary recruitment of flexible Esrp-dependent splicing programs into diverse embryonic morphogenetic processes

      Burguera, D; Marquez, Y; Racioppi, C; Permanyer, J; Torres-Mendez, A; Esposito, R; Albuixech-Crespo, B; Fanlo, L; D'Agostino, Y; Gohr, A; et al. (2017-12)
      Epithelial-mesenchymal interactions are crucial for the development of numerous animal structures. Thus, unraveling how molecular tools are recruited in different lineages to control interplays between these tissues is key to understanding morphogenetic evolution. Here, we study Esrp genes, which regulate extensive splicing programs and are essential for mammalian organogenesis. We find that Esrp homologs have been independently recruited for the development of multiple structures across deuterostomes. Although Esrp is involved in a wide variety of ontogenetic processes, our results suggest ancient roles in non-neural ectoderm and regulating specific mesenchymal-to-epithelial transitions in deuterostome ancestors. However, consistent with the extensive rewiring of Esrp-dependent splicing programs between phyla, most developmental defects observed in vertebrate mutants are related to other types of morphogenetic processes. This is likely connected to the origin of an event in Fgfr, which was recruited as an Esrp target in stem chordates and subsequently co-opted into the development of many novel traits in vertebrates.
    • Examination of types in the Fragilaria vaucheriae–intermedia species complex

      Tuji, A; Williams, DM (National Museum of Science and Nature, 2013-02-22)
      In a previous paper, we presented the results of type examination of the Fragilaria pectinalis–capitellata species complex, species which have a unilateral central area and fine striae. Here, we present the results of type examination of the Fragilaria vaucheriae–intermedia species complex, species which have a unilateral central area and coarse striae (<13 striae per 10 µm). Synedra vaucheriae var. doformis Grunow and S. vaucheriae var. distans Grunow are synonyms of F. vauchriae (Kütz.) J.B.Petersen. F. intermedia Grunow is also a synonym of F. vauchriae. However, some of the figures for F. intermedia that were published by Van Heurck are a new taxon sometimes identified as F. intermedia. This new taxon is described here as Fragilaria neointermedia.
    • Exploration of the Mid-Cayman Rise

      German, CR; Tyler, PA; McIntyre, C; Amon, Diva; Cheadle, M; Clarke, J; John, B; McDermott, JM; Bennett, SA; Huber, JA; et al. (The Oceanography Society, 2012)
    • Exploration of the Southern California Borderland

      Cormier, M-H; Bell, KLC; Sharuga, SM; Castillo, C; Conrad, J; Amon, Diva; Legg, M; Brennan, ML; Barnhill, K; Lovell, LL; et al. (The Oceanography Society, 2017-03-01)
    • Exploring molecular variation in Schistosoma japonicum in China

      Young, ND; Chan, K-G; Korhonen, PK; Chong, TM; Ee, R; Mohandas, N; Koehler, AV; Lim, Y-L; Hofmann, A; Jex, AR; et al. (2015-12)
    • Extended Pelagic Life in a Bathybenthic Octopus

      Villanueva, Roger; Laptikhovsky, Vladimir V; Piertney, Stuart B; Fernández-Álvarez, Fernando Ángel; Collins, Martin A; Ablett, J; Escánez, Alejandro (Frontiers Media SA, 2020-11-20)
      Planktonic stages of benthic octopuses can reach relatively large sizes in some species, usually in oceanic, epipelagic waters while living as part of the macroplankton. These young octopuses appear to delay settlement on the seabed for an undetermined period of time that is probably longer than for those octopus paralarvae living in coastal, neritic waters. The reason for this delay is unknown and existing information about their biology is very scarce. Here we report on the presence of juvenile and subadult forms of the bathybenthic octopus Pteroctopus tetracirrhus in oceanic waters of the South and North Atlantic and its association with the pyrosomid species Pyrosoma atlanticum, apparently used by the octopus as a refuge or shelter. The relatively large size of the P. tetracirrhus living in oceanic waters as the individuals reported here, together with the morphological characteristics of this bathybenthic species including its gelatinous body, minute suckers embedded in swollen skin and the deep interbrachial web, indicates that P. tetracirrhus may be considered a model of a transitional octopus species that is colonizing the pelagic environment by avoiding descending to the bathyal benthos. This process seems to occur in the same way as in the supposed origin of the ctenoglossan holopelagic octopods of the families Amphitretidae, Bolitaenidae, and Vitreledonellidae, which have arisen via neoteny from the planktonic paralarval stages of benthic octopuses.
    • Extensive sampling and thorough taxonomic assessment of Afrotropical Rhyssinae (Hymenoptera, Ichneumonidae) reveals two new species and demonstrates the limitations of previous sampling efforts

      Hopkins, T; Roininen, H; van Noort, S; Broad, G; Kaunisto, K; Sääksjärvi, IE (Pensoft Publishers, 2019-10-07)
      Tropical forest invertebrates, such as the parasitoid wasp family Ichneumonidae, are poorly known. This work reports some of the first results of an extensive survey implemented in Kibale National Park, Uganda. A total of 456 individuals was caught of the subfamily Rhyssinae Morley, 1913, which in the Afrotropical region was previously known from only 30 specimens. Here, the six species found at the site are described and the Afrotropical Rhyssinae are reviewed. Two new species, Epirhyssa johanna Hopkins, sp. nov. and E. quagga sp. nov., are described and a key, diagnostic characters, and descriptions for all 13 known Afrotropical species are provided, including the first description of the male of Epirhyssa overlaeti Seyrig, 1937. Epirhyssa gavinbroadi Rousse & van Noort, 2014, syn. nov. is proposed to be a synonym of E. uelensis Benoit, 1951. Extensive sampling with Malaise traps gave an unprecedented sample size, and the method is recommended for other poorly known tropical areas.
    • Extensive Uncharted Biodiversity: The Parasite Dimension

      Okamura, B; Hartigan, A; Naldoni, J (Oxford University Press, 2018-09-18)
      Parasites are often hidden in their hosts and exhibit patchy spatial distributions. This makes them relatively difficult to detect and sample. Consequently we have poor knowledge of parasite diversities, distributions, and extinction. We evaluate our general understanding of parasite diversity and highlight the enormous bias in research on parasites such as helminths and arthropods that infect vertebrate hosts. We then focus on Myxozoa as an exemplary case for demonstrating uncharted parasite diversity. Myxozoans are a poorly recognized but speciose clade of endoparasitic cnidarians with complex life cycles that have radiated to exploit freshwater, marine, and terrestrial hosts by adopting strategies convergent to those of parasitic protists. Myxozoans are estimated to represent some 20% of described cnidarian species—greatly outnumbering the combined species richness of scyphozoans, cubozoans, and staurozoans. We summarize limited understanding of myxozoan diversification and geographical distributions, and highlight gaps in knowledge and approaches for measuring myxozoan diversity. We close by reviewing methods and problems in estimating parasite extinction and concerns about extinction risks in view of the fundamental roles parasites play in ecosystem dynamics and in driving host evolutionary trajectories.