Understanding the diversity and spatial distribution of benthic species is fundamental to properly assess the impact of deep sea mining. Tanaidacea provide an exceptional opportunity for assessing ...spatial patterns in the deep-sea, given their low mobility and limited dispersal potential. The diversity and distribution of pseudotanaid species is characterized here for the Clarion and Clipperton Fractures Zone (CCZ), which is the most extensive deposit field of metallic nodules. Samples were taken from the Belgian, German and French license areas, but also from the APEI 3 (Area of Particular Environmental Interest 3) of the Interoceanmetal consortium associates. The combination of morphological and genetic data uncovered one new pseudotanaid genus (Beksitanais n. gen.) and 14 new species of Pseudotanais (2 of them virtual taxa). Moreover, our results suggest that spatial structuring of pseudotanaid diversity is correlated with deep-sea features, particularly the presence of fractures and seamount chains crossing the CCZ. The presence of geographical barriers delimiting species distributions has important implications for the establishment of protected areas, and the APEI3 protected area contains only one third of the total pseudotanaid species in CCZ. The specimen collection studied here is extremely valuable and represents an important first step in characterizing the diversity and distribution of pseudotanaids within the Tropical Eastern Pacific.
Recombination is a pervasive process generating diversity in most viruses. It joins variants that arise independently within the same molecule, creating new opportunities for viruses to overcome ...selective pressures and to adapt to new environments and hosts. Consequently, the analysis of viral recombination attracts the interest of clinicians, epidemiologists, molecular biologists and evolutionary biologists. In this review we present an overview of three major areas related to viral recombination: (i) the molecular mechanisms that underlie recombination in model viruses, including DNA-viruses (Herpesvirus) and RNA-viruses (Human Influenza Virus and Human Immunodeficiency Virus), (ii) the analytical procedures to detect recombination in viral sequences and to determine the recombination breakpoints, along with the conceptual and methodological tools currently used and a brief overview of the impact of new sequencing technologies on the detection of recombination, and (iii) the major areas in the evolutionary analysis of viral populations on which recombination has an impact. These include the evaluation of selective pressures acting on viral populations, the application of evolutionary reconstructions in the characterization of centralized genes for vaccine design, and the evaluation of linkage disequilibrium and population structure.
The reed bunting, Emberiza schoeniclus (Linnaeus 1758), is the only member of the genus adapted to Mediterranean wetlands, where some subspecies are critically endangered. The first complete ...mitogenome of the eastern Iberian reed bunting (E. s. witherbyi) is presented here and compared with an unpublished mitogenome obtained in northeast Asia (most likely E. s. pyrrhulina). Genetic distance analyses are consistent with the new reed bunting data corresponding to two distinct lineages of E. schoeniclus. A new fossil‐calibrated phylogeny suggests that open forest buntings have suffered two rapid speciation events from Late Miocene to Pleistocene, that seem to be correlated with major climatic changes and habitat shifts. Adaptation to a new ecological niche (i.e. wetlands) could have favoured the reed bunting expansion across the Palearctic. The high intraspecific variation observed today could result from the establishment of resident populations within small areas, potentially acting as a climatic refuge.
Re-examination of historical collections allowed us to resolve the taxonomic status of
Kudinova-Pasternak, 1985, originally described based on a single specimen from Great-Meteor Seamount. The ...holotype of this species was considered lost and the species redescribed based on a second specimen from the type locality by Błażewicz-Paszkowycz (2007a), who placed
on a newly established genus
. Thorough morphological analysis of
and
species and recently obtained genetic data of typhlotanaids from N Atlantic and NW Pacific waters allow us to conclude that the redescription of
by Błażewicz-Paszkowycz (2007a) was based on a wrongly labelled specimen that, rather than a type of
, represents in fact a new species of
. The morphological comparison of the type species of
(
) with all 'long-bodied' typhlotanaid taxa with rounded pereonites margins (
.,
), and the use of genetic evidence, support the establishment of a new genus to accommodate:
,
Kudinova-Pasternak, 1989, and a third species from N Atlantic waters, that is described here for the first time. Current knowledge on 'long-bodied' typhlotanaids with rounded pereonites is summarised and a taxonomical key for their identification provided.
•High diversity was recorded on the shelf in an area characterized by high habitat heterogeneity.•A highly patchy distribution of decapods was recorded.•Low abundance and diversity were observed on ...the slope, an area dominated by silt clay deposits and elevated concentrations of barium and hydrocarbons.
Sixty morphospecies of Decapoda (Malacostraca: Crustacea) representing 34 families were recorded in the material collected in 2012 from 265 van Veen grab (0.1 m2) samples, from the nine transects distributed along the coast of Ghana in the 25–1000 m depth range. The examined material was dominated by the Diogenidae, Panopeidae, Leucosiidae, Pilumnidae and Xanthidae families. Species accumulation curves showed undersampling of the studied area and a large number of the morphospecies comprised singletons and doubletons. Panopeus africanus was the most frequent morphospecies in the analysed material (9.1% of all samples). We observed a substantial decrease of diversity (Shannon Index) and abundance along a depth gradient. Species richness also decreased with depth, starting from the highest number of morphospecies ‒ 38 at 25 m depth, then 33 at 50 m, 17 at 100 m, 11 at 250 m, 8 at 500 m and ending with 1 morphospecies at 1000 m bottom depth. Higher diversity was observed on the continental shelf (25–250 m – 57 morphospecies), while on the slope (500–1000 m) only eight morphospecies were recorded. Numerous factors of natural and anthropogenic origin may affect decapod communities on the coast of Ghana. Since our material was collected using a sampler collecting material at a very small scale, the observed patterns might be affected by the sampling method.
The two widespread ostracod genera Cypria Zenker, 1854 and Physocypria Vávra, 1897 are traditionally distinguished based on the presence or absence of tubercles on the right valve margin. However, ...recent research based on soft body parts has uncovered new cryptic genera within Cypria and Physocypria. Following this line of research, a new Cyclocyprididae genus and species, Vizcainocypria viator gen. nov. sp. nov., is here described from individuals collected in rice fields and wetlands of the Iberian Peninsula. Vizcainocypria is compared with Cypria, Physocypria, Dentocypria Savatenalinton, 2017, Keysercypria Karanovic, 2011, Brasilocypria Almeida et al., 2023, and Claudecypria Almeida et al., 2023 based on morphological evidence. Besides the presence or absence of tubercles on the right valve, these genera can be distinguished according to their mandibular palp, second thoracopod, caudal ramus, and male hemipenis. Molecular analyses using mitochondrial (COX1), and nuclear (28S rDNA) genes provide further support for the differentiation of Cypria, Dentocypria, Physocypria and Vizcainocypria gen. nov. The present study highlights the importance of using an integrative taxonomy approach, combining shell and soft-body parts morphology and molecular data, to characterize the rich diversity of freshwater ostracods.
Typhlotanaidae Sieg, 1984, is one of the most diverse Tanaidacea families from deep-sea waters. Its diversity is underestimated, and evolutionary relationships within the family remain mostly ...unknown. Deep-sea typhlotanaids collected from 23 sites across the Kuril-Kamchatka Trench and nearby waters were studied using an integrative taxonomy approach, combining morphological and genetic data (i.e., the mitochondrial subunit I of the cytochrome oxidase (COI) and the 18S rDNA nuclear gene). One new species of
Typhlamia
and two new species belonging to two new genera are described, significantly increasing the known diversity of typhlotanaids from the NW Pacific. The molecular phylogeny obtained, despite being preliminary results, was congruent with morphological data and supports the monophyly of different groups such as the ‘short-bodied’ forms (represented by
Ty. cornutus
and
Ty. eximius
) or the ‘collar’ forms (e.g.,
Ty. variabilis
and
Torquella
). Molecular data confirm the non-monophyly of
Typhlotanais
species. Finally, the new typhlotanaid taxa seem to have distinct bathymetric distribution and ecological requirements, but further data on environmental factors and species abundances are still needed.
Interactions between pathogenic oomycetes and microbiota residing on the surface of the host plant root are unknown, despite being critical to inoculum constitution. The nature of these interactions ...was explored for the polyphagous and telluric species Phytophthora parasitica.
Composition of the rhizospheric microbiota of Solanum lycopersicum was characterized using deep re-sequencing of 16S rRNA gene to analyze tomato roots either free of or partly covered with P. parasitica biofilm. Colonization of the host root surface by the oomycete was associated with a shift in microbial community involving a Bacteroidetes/Proteobacteria transition and Flavobacteriaceae as the most abundant family. Identification of members of the P. parasitica-associated microbiota interfering with biology and oomycete infection was carried out by screening for bacteria able to (i) grow on a P. parasitica extract-based medium (ii), exhibit in vitro probiotic or antibiotic activity towards the oomycete (iii), have an impact on the oomycete infection cycle in a tripartite interaction S. lycopersicum-P. parasitica-bacteria. One Pseudomonas phylotype was found to exacerbate disease symptoms in tomato plants. The lack of significant gene expression response of P. parasitica effectors to Pseudomonas suggested that the increase in plant susceptibility was not associated with an increase in virulence. Our results reveal that Pseudomonas spp. establishes commensal interactions with the oomycete. Bacteria preferentially colonize the surface of the biofilm rather than the roots, so that they can infect plant cells without any apparent infection of P. parasitica.
The presence of the pathogenic oomycete P. parasitica in the tomato rhizosphere leads to a shift in the rhizospheric microbiota composition. It contributes to the habitat extension of Pseudomonas species mediated through a physical association between the oomycete and the bacteria.
The accurate assignment of cryptic larvae to species-level is a key aspect of marine ecological research and can be achieved through integrated molecular and morphological studies. A combination of ...two mitochondrial markers (COI and 16S) and a detailed morphological analysis was used to identify phyllosoma larvae of slipper lobster (Scyllaridae) species collected during a survey in the SW Indian Ocean. Two morphotypes were tentatively assigned to Acantharctus ornatus and Biarctus pumilus, both genera for which the larval morphology was unknown. Morphological revision of an adult specimen used to generate the putative A. ornatus sequences in GenBank revealed that it was misidentified and corresponds to B. dubius. The final phyllosoma stage of B. pumilus and subfinal and final stages of A. ornatus were described, clarifying prior misidentifications in the literature. Scyllarid biodiversity in the SW Indian Ocean is underestimated and sampling of deeper water layers is recommended to complete current knowledge of species and larval stages present in the region.
Delottococcus aberiae De Lotto (Hemiptera: Pseudococcidae) is a mealybug of Southern African origin that has recently been introduced into Eastern Spain. It causes severe distortions on young citrus ...fruits and represents a growing threat to Mediterranean citrus production. So far, biological control has proven unsatisfactory due to the absence of efficient natural enemies in Spain. Hence, the management of this pest currently relies only on chemical control. The introduction of natural enemies of D. aberiae from the native area of the pest represents a sustainable and economically viable alternative to reduce the risks linked to pesticide applications. Since biological control of mealybugs has been traditionally challenged by taxonomic misidentification, an intensive survey of Delottococcus spp. and their associated parasitoids in South Africa was required as a first step towards a classical biological control programme. Combining morphological and molecular characterization (integrative taxonomy) a total of nine mealybug species were identified in this study, including three species of Delottococcus. Different populations of D. aberiae were found on wild olive trees, in citrus orchards and on plants of Chrysanthemoides monilifera, showing intra-specific divergences according to their host plants. Interestingly, the invasive mealybug populations from Spanish orchards clustered together with the population on citrus from Limpopo Province (South Africa), sharing COI haplotypes. This result pointed to an optimum location to collect natural enemies against the invasive mealybug. A total of 14 parasitoid species were recovered from Delottococcus spp. and identified to genus and species level, by integrating morphological and molecular data. A parasitoid belonging to the genus Anagyrus, collected from D. aberiae in citrus orchards in Limpopo, is proposed here as a good biological control agent to be introduced into Spain.
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