• 3D virtual histology at the host/parasite interface: visualisation of the master manipulator, Dicrocoelium dendriticum, in the brain of its ant host

      Martin-Vega, D; Garbout, A; Ahmed, F; Wicklein, M; Goater, CP; Colwell, DD; Hall, MJR (Springer Science and Business Media LLC, 2018-06-05)
      Some parasites are able to manipulate the behaviour of their hosts to their own advantage. One of the most well-established textbook examples of host manipulation is that of the trematode Dicrocoelium dendriticum on ants, its second intermediate host. Infected ants harbour encysted metacercariae in the gaster and a non-encysted metacercaria in the suboesophageal ganglion (SOG); however, the mechanisms that D. dendriticum uses to manipulate the ant behaviour remain unknown, partly because of a lack of a proper and direct visualisation of the physical interface between the parasite and the ant brain tissue. Here we provide new insights into the potential mechanisms that this iconic manipulator uses to alter its host’s behaviour by characterising the interface between D. dendriticum and the ant tissues with the use of non-invasive micro-CT scanning. For the first time, we show that there is a physical contact between the parasite and the ant brain tissue at the anteriormost part of the SOG, including in a case of multiple brain infection where only the parasite lodged in the most anterior part of the SOG was in contact with the ant brain tissue. We demonstrate the potential of micro-CT to further understand other parasite/host systems in parasitological research.
    • The All-Data-Based Evolutionary Hypothesis of Ciliated Protists with a Revised Classification of the Phylum Ciliophora (Eukaryota, Alveolata)

      Gao, F; Zhang, Q; Gong, J; Miao, M; Sun, P; Xu, D; Huang, J; Yi, Z; Song, W; Warren, A (2016-07)
    • Ancient mitogenomics clarifies radiation of extinct Mascarene giant tortoises (Cylindraspis spp.)

      Kehlmaier, C; Graciá, E; Campbell, P; Hofmeyr, MD; SCHWEIGER, S; Martínez-Silvestre, A; Joyce, W; Fritz, U (Springer Science and Business Media LLC, 2019-11-25)
      The five extinct giant tortoises of the genus Cylindraspis belong to the most iconic species of the enigmatic fauna of the Mascarene Islands that went largely extinct after the discovery of the islands. To resolve the phylogeny and biogeography of Cylindraspis, we analysed a data set of 45 mitogenomes that includes all lineages of extant tortoises and eight near-complete sequences of all Mascarene species extracted from historic and subfossil material. Cylindraspis is an ancient lineage that diverged as early as the late Eocene. Diversification of Cylindraspis commenced in the mid-Oligocene, long before the formation of the Mascarene Islands. This rejects any notion suggesting that the group either arrived from nearby or distant continents over the course of the last millions of years or had even been translocated to the islands by humans. Instead, Cylindraspis likely originated on now submerged islands of the Réunion Hotspot and utilized these to island hop to reach the Mascarenes. The final diversification took place both before and after the arrival on the Mascarenes. With Cylindraspis a deeply divergent clade of tortoises became extinct that evolved long before the dodo or the Rodrigues solitaire, two other charismatic species of the lost Mascarene fauna.
    • Convergent evolution of an extreme dietary specialisation, the olfactory system of worm-eating rodents

      Martinez, Q; Lebrun, R; Achmadi, AS; Esselstyn, JA; Evans, AR; Heaney, LR; Portela Miguez, R; Rowe, KC; Fabre, P-H (Nature Research, 2018-12-13)
      Turbinal bones are key components of the mammalian rostrum that contribute to three critical functions: (1) homeothermy, (2) water conservation and (3) olfaction. With over 700 extant species, murine rodents (Murinae) are the most species-rich mammalian subfamily, with most of that diversity residing in the Indo-Australian Archipelago. Their evolutionary history includes several cases of putative, but untested ecomorphological convergence, especially with traits related to diet. Among the most spectacular rodent ecomorphs are the vermivores which independently evolved in several island systems. We used 3D CT-scans (N = 87) of murine turbinal bones to quantify olfactory capacities as well as heat or water conservation adaptations. We obtained similar results from an existing 2D complexity method and two new 3D methodologies that quantify bone complexity. Using comparative phylogenetic methods, we identified a significant convergent signal in the rostral morphology within the highly specialised vermivores. Vermivorous species have significantly larger and more complex olfactory turbinals than do carnivores and omnivores. Increased olfactory capacities may be a major adaptive feature facilitating rats’ capacity to prey on elusive earthworms. The narrow snout that characterises vermivores exhibits significantly reduced respiratory turbinals, which may reduce their heat and water conservation capacities.
    • Ecology and biogeography of megafauna and macrofauna at the first known deep-sea hydrothermal vents on the ultraslow-spreading Southwest Indian Ridge

      Copley, JT; Marsh, L; Glover, AG; Hühnerbach, V; Nye, VE; Reid, WDK; Sweeting, CJ; Wigham, BD; Wiklund, H (2016-12)
    • 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)
    • The first global deep-sea stable isotope assessment reveals the unique trophic ecology of Vampire Squid Vampyroteuthis infernalis (Cephalopoda)

      Golikov, A; Ceia, F; Sabirov, R; Ablett, J; Gleadall, I; Gudmundsson, G; Hoving, H; Heather, J; Pálsson, J; Reid, AL; et al. (Nature Publishing Group, 2019-12-13)
      Vampyroteuthis infernalis Chun, 1903, is a widely distributed deepwater cephalopod with unique morphology and phylogenetic position. We assessed its habitat and trophic ecology on a global scale via stable isotope analyses of a unique collection of beaks from 104 specimens from the Atlantic, Pacific and Indian Oceans. Cephalopods typically are active predators occupying a high trophic level (TL) and exhibit an ontogenetic increase in δ15N and TL. Our results, presenting the first global comparison for a deep-sea invertebrate, demonstrate that V. infernalis has an ontogenetic decrease in δ15N and TL, coupled with niche broadening. Juveniles are mobile zooplanktivores, while larger Vampyroteuthis are slow-swimming opportunistic consumers and ingest particulate organic matter. Vampyroteuthis infernalis occupies the same TL (3.0–4.3) over its global range and has a unique niche in deep-sea ecosystems. These traits have enabled the success and abundance of this relict species inhabiting the largest ecological realm on the planet.
    • Insights into the abundance and diversity of abyssal megafauna in a polymetallic-nodule region in the eastern Clarion-Clipperton Zone

      Amon, Diva; Ziegler, AF; Dahlgren, TG; Glover, AG; Goineau, A; Gooday, AJ; Wiklund, H; Smith, CR (Springer, 2016-07-29)
      There is growing interest in mining polymetallic nodules in the abyssal Clarion-Clipperton Zone (CCZ) in the Pacific. Nonetheless, benthic communities in this region remain poorly known. The ABYSSLINE Project is conducting benthic biological baseline surveys for the UK Seabed Resources Ltd. exploration contract area (UK-1) in the CCZ. Using a Remotely Operated Vehicle, we surveyed megafauna at four sites within a 900 km2 stratum in the UK-1 contract area, and at a site ~250 km east of the UK-1 area, allowing us to make the first estimates of abundance and diversity. We distinguished 170 morphotypes within the UK-1 contract area but species-richness estimators suggest this could be as high as 229. Megafaunal abundance averaged 1.48 ind. m−2. Seven of 12 collected metazoan species were new to science, and four belonged to new genera. Approximately half of the morphotypes occurred only on polymetallic nodules. There were weak, but statistically significant, positive correlations between megafaunal and nodule abundance. Eastern-CCZ megafaunal diversity is high relative to two abyssal datasets from other regions, however comparisons with CCZ and DISCOL datasets are problematic given the lack of standardised methods and taxonomy. We postulate that CCZ megafaunal diversity is driven in part by habitat heterogeneity.
    • Mitogenomics of historical type specimens of Australasian turtles: clarification of taxonomic confusion and old mitochondrial introgression

      Kehlmaier, C; Zhang, X; Georges, A; Campbell, P; Thomson, S; Fritz, U (Springer Nature, 2019-04-09)
      Diagnosability is central to taxonomy as are type specimens which define taxa. New advances in technologies and the discovery of new informative traits must be matched with previous taxonomic decisions based on name-bearing type specimens. Consequently, the challenge of sequencing highly degraded DNA from historical types becomes an inevitability to resolve the very many taxonomic issues arising from, by modern standards, poor historical species descriptions leading to difficulties to assign names to genetic clusters identified from fresh material. Here we apply high-throughput parallel sequencing and sequence baiting to reconstruct the mitogenomes from 18 type specimens of Australasian side-necked turtles (Chelidae). We resolve a number of important issues that have confused the taxonomy of this family, and analyse the mitogenomes of the types and those of fresh material to improve our understanding of the phylogenetic relationships of this morphologically conservative group. Together with previously published nuclear genomic data, our study provides evidence for multiple old mitochondrial introgressions.
    • North Andean origin and diversification of the largest ithomiine butterfly genus

      Lisa De-Silva, D; Mota, LL; Chazot, N; Mallarino, R; Silva-Brandão, KL; Piñerez, LM; Freitas, AV; Lamas, G; Joron, M; Mallet, J; et al. (2017-12)
    • Novel molecular approach to define pest species status and tritrophic interactions from historical Bemisia specimens

      Tay, WT; Elfekih, S; Polaszek, Andrew; Court, LN; Evans, GA; Gordon, KHJ; De Barro, PJ (Nature Research, 2017-03-27)
      Museum specimens represent valuable genomic resources for understanding host-endosymbiont/parasitoid evolutionary relationships, resolving species complexes and nomenclatural problems. However, museum collections suffer DNA degradation, making them challenging for molecular-based studies. Here, the mitogenomes of a single 1912 Sri Lankan Bemisia emiliae cotype puparium, and of a 1942 Japanese Bemisia puparium are characterised using a Next-Generation Sequencing approach. Whiteflies are small sap-sucking insects including B. tabaci pest species complex. Bemisia emiliae’s draft mitogenome showed a high degree of homology with published B. tabaci mitogenomes, and exhibited 98–100% partial mitochondrial DNA Cytochrome Oxidase I (mtCOI) gene identity with the B. tabaci species known as Asia II-7. The partial mtCOI gene of the Japanese specimen shared 99% sequence identity with the Bemisia ‘JpL’ genetic group. Metagenomic analysis identified bacterial sequences in both Bemisia specimens, while hymenopteran sequences were also identified in the Japanese Bemisia puparium, including complete mtCOI and rRNA genes, and various partial mtDNA genes. At 88–90% mtCOI sequence identity to Aphelinidae wasps, we concluded that the 1942 Bemisia nymph was parasitized by an Eretmocerus parasitoid wasp. Our approach enables the characterisation of genomes and associated metagenomic communities of museum specimens using 1.5 ng gDNA, and to infer historical tritrophic relationships in Bemisia whiteflies.
    • PCB pollution continues to impact populations of orcas and other dolphins in European waters

      Jepson, PD; Deaville, R; Barber, JL; Aguilar, A; Borrell, A; Murphy, S; Barry, J; Brownlow, A; Barnett, J; Berrow, S; et al. (2016-05)
    • Predicting bee community responses to land-use changes: Effects of geographic and taxonomic biases

      De Palma, A; Abrahamczyk, S; Aizen, MA; Albrecht, M; Basset, Y; Bates, A; Blake, RJ; Boutin, C; Bugter, R; Connop, S; et al. (2016-11)
    • Structural colour in Chondrus crispus

      Chandler, CJ; Wilts, BD; Vignolini, S; Brodie, J; Steiner, U; Rudall, PJ; Glover, BJ; Gregory, T; Walker, RH (2015-12)
    • The utility of micro-computed tomography for the non-destructive study of eye microstructure in snails

      Sumner-Rooney, L; Kenny, Nathan; Ahmed, F; Williams, ST (Springer Science and Business Media LLC, 2019-10-28)
      Molluscan eyes exhibit an enormous range of morphological variation, ranging from tiny pigment-cup eyes in limpets, compound eyes in ark clams and pinhole eyes in Nautilus, through to concave mirror eyes in scallops and the large camera-type eyes of the more derived cephalopods. Here we assess the potential of non-destructive micro-computed tomography (µ-CT) for investigating the anatomy of molluscan eyes in three species of the family Solariellidae, a group of small, deep-sea gastropods. We compare our results directly with those from traditional histological methods applied to the same specimens, and show not only that eye microstructure can be visualised in sufficient detail for meaningful comparison even in very small animals, but also that μ-CT can provide additional insight into gross neuroanatomy without damaging rare and precious specimens. Data from μ-CT scans also show that neurological innervation of eyes is reduced in dark-adapted snails when compared with the innervation of cephalic tentacles, which are involved in mechanoreception and possibly chemoreception. Molecular tests also show that the use of µ-CT and phosphotungstic acid stain do not prevent successful downstream DNA extraction, PCR amplification or sequencing. The use of µ-CT methods is therefore highly recommended for the investigation of difficult-to-collect or unique specimens.
    • Whole genome resequencing of the human parasite Schistosoma mansoni reveals population history and effects of selection

      Crellen, T; Allan, F; David, S; Durrant, C; Huckvale, T; Holroyd, N; Emery, AM; Rollinson, D; Aanensen, DM; Berriman, M; et al. (2016-08)