Classical Morphological Approaches Research Articles

Using the Integrative Approach to Update a Gap of One Century: Redescription and New Distribution Records of the South American Tarantulas Grammostola pulchra (Araneae: Mygalomorphae: Theraphosidae).

Taxonomic researchers have used multiple sources of evidence to support species hypotheses and delimitations. Grammostola Simon (Mygalomorphae: Theraphosidae) comprises 20 valid species endemic to South America, six occurring in Brazil. The classical morphological approach based mainly on genitalia may be misleading in recognizing species in this genus. Thus, we used morphology, geographical distribution, genetic distance, and phylogeny to support the redescription of Grammostola pulchra from southern Brazil, a species described a century ago. We also diagnosed and illustrated the species. Males have a developed apical keel at the apex of the embolus; for the first time, this type of structure has been reported in a species of Grammostola. The molecular analyses using the partial sequence of Cytochrome c oxidase subunit I showed 7% of genetic distance (p-distance) between G. pulchra and Grammostola anthracina. Distance and tree-based methods (ASAP and bPTP, respectively) assigned G. pulchra as a valid species. The gene-tree under Bayesian and Maximum-Likelihood recovered a similar topology, placing G. pulchra as closely related to Grammostola burzaquensis and G. anthracina. Morphological characters which could be important in the taxonomy of the genus are further discussed.

Trematodes of Genera Gyrabascus and Parabascus from Bats in European Russia: Morphology and Molecular Phylogeny.

Simple SummaryThe ecology of bats determines their unique parasitic fauna. Most species of worms from bats are highly specialized parasites. We studied parasitic worms of bats that died of natural causes, using classical morphological and molecular phylogenetic approaches. Original drawings, descriptions, and results of molecular phylogenetic analysis for five species of trematodes were provided. We established a broad morphological variability in the studied trematode species, which means that the identification of closely related species may be problematic for researchers. We proposed a taxonomic key for the reliable identification of the studied trematode species. The results of our study contribute to the knowledge of bat helminths and host-parasite relationships in general.Morphological variability of trematodes from bats (Chiroptera) is poorly studied. Since the variability of adult digenean specimens may be rather high, morphological features are often insufficient for the identification of closely related species, and confirmation with the use of molecular data is required. The aim of our study was to combine the morphological and molecular phylogenetic analyses of several bat trematodes from the genera Gyrabascus and Parabascus (Pleurogenidae): Gyrabascus amphoraeformis, Gyrabascus oppositus, Parabascus lepidotus, Parabascus duboisi, and Parabascus semisquamosus, of which G. amphoraeformis and G. oppositus are little known in European Russia. We made detailed morphological descriptions of these trematodes from several definitive hosts, analyzed morphometric features, and generated new partial sequences of the 28S rRNA gene. A broad variability of trematodes of the genera Gyrabascus and Parabascus was revealed both from various host species and from specimens of the same host species. We propose a new taxonomic key for the identification of the studied species. Certain host specificity of these trematodes was revealed.

Toxic effect of the titanium dioxide rutile form on the morphological characteristics of the immune system organs

The aim. To study the effect of the rutile form of titanium dioxide upon its oral administration on the morphological and functional state of the organs of the immune system of rats. Materials and methods. In this work, using classical morphological approaches and specific markers: proliferation - Ki-67, PCNA, apoptosis - protein p53 and macrophages - CD68, which make it possible to adequately identify not only the cells themselves, but also their functional state, a study of the spleen and thymus of rats after oral administration (10 mg/kg animal body weight, 28 days) of a nanodispersed form of TiO2 (rutile form, 40-60 nm) obtained by diluting TiO2 powder in distilled water was carried out. Aggregation of nanoparticles was prevented by treatment of a suspension of nanodispersed TiO2 in an ultrasonic bath. Rats of the control group were orally administered with distilled water in the same volume. Results. With oral administration of the rutile form of nanodispersed TiO2, a moderate accidental involution of the thymus is observed, a reduction in the white pulp of the spleen, due to a decrease in the proliferative potential and an increase in apoptosis. The revealed morphofunctional changes in lymphoid organs can be interpreted from the standpoint of induced secondary immunodeficiency that develops against the background of exposure to rutile TiO2 NPs. Limitations. When studying the effect of titanium dioxide (rutile, 40-60 nm, 10 mg/kg of animal body weight) on the morphological characteristics of the immune defense organs, the sample size was 12 Wistar rats, the maximum duration of exposure was 28 days. Conclusion. The detected morphofunctional changes in the lymphoid organs can be interpreted from the position of induced secondary immunodeficiency, developing against the background of exposure to NPS TiO2 of the rutile modification.

Breathing versus feeding in the Pacific hagfish.

Hagfish represent the oldest extant connection to the ancestral vertebrates, but their physiology is not well understood. Using behavioural (video), physiological (respirometry, flow measurements), classical morphological (dissection, silicone injection) and modern imaging approaches (micro-MRI, DICE micro-CT), we examined the interface between feeding and the unique breathing mechanism (nostril opening, high-frequency velum contraction, low-frequency gill pouch contraction and pharyngo-cutaneous duct contraction) in the Pacific hagfish, Eptatretus stoutii. A video tour via micro-MRI is presented through the breathing and feeding passages. We have reconciled an earlier disagreement as to the position of the velum chamber, which powers inhalation through the nostril, placing it downstream of the merging point of the food and water passage, such that the oronasal septum terminates at the anterior end of the velum chamber. When feeding occurs by engulfment of large chunks by the dental plates, food movement through the chamber may transiently interfere with breathing. Swallowing is accelerated by peristaltic body undulation involving the ventral musculature, and is complete within 5 s. After a large meal (anchovy, 20% body mass), hagfish remain motionless, defaecating bones and scales at 1.7 days and an intestinal peritrophic membrane at 5 days. O2 consumption rate approximately doubles within 1 h of feeding, remaining elevated for 12-24 h. This is achieved by combinations of elevated O2 utilization and ventilatory flow, the latter caused by varying increases in velar contraction frequency and stroke volume. Additional imaging casts light on the reasons for the trend for greater O2 utilization by more posterior pouches and the pharyngo-cutaneous duct in fasted hagfish.

Notes on the taxonomy of species of Sciomyzini with a predominantly setulose anepisternum (Diptera, Sciomyzidae)

The present paper was conceived originally as a straightforward, simple description of a new African taxon. It grew substantially as more research was conducted. It now consists of four parts. In Part I, we discuss the taxonomy of five species of Sciomyzini with a predominantly setulose anepisternum: Atrichomelina pubera, Ditaeniella grisescens, D. trivittata, Pherbellia pilosa, and Ph. shatalkini. In Parts II and III, we consider the three taxa initially included in the genus Ditaeniella sensu Rozkošný (1987) (D. grisescens, D. parallela, and D. patagonensis) and the taxon described herein, D. milleri sp. nov., analysing this group by use of both the classical morphological approach (Part II) as well as by analysis of molecular data from available DNA barcodes (Part III). In Part IV, we provide a key to the taxa of Sciomyzini worldwide that have a predominantly setulose anepisternum. We also provide a list of specimens examined, the data from which significantly supplement the information previously available regarding the distribution of several Palaearctic species.

Composition of diatom communities on travertine barriers of the Una River (Bosnia and Herzegovina) obtained by DNA metabarcoding and morphological analysis

The process of travertine formation and carbonate deposition in the rivers is unique, delicate, and depends on the activity of algae and mosses. Although diatoms have been used extensively in hydrobiological studies, the comparative analysis data on diatom communities of the travertine barriers in karstic rivers are still scarce. The study aimed to detect the diatom composition on travertine barriers in the Una River, the large karstic river in Bosnia and Herzegovina. An integrated classical morphological identification approach with metabarcoding was applied on eight samples across the river length profile. Morphological analyses were performed using both light and scanning electron microscopes. Subsequent DNA metabarcoding of the chloroplastic gene 312bp rbcL was done. The DADA2 pipeline was used for the bioinformatic treatment of the demultiplexed MiSeq reads to infer Amplicon Sequence Variants (ASVs). ASVs were taxonomically assigned using the Diat.barcode v7 reference database. A total of 126 species were identified using the morphological approach, while 133 ASVs were taxonomically assigned to 58 unique taxa with the molecular approach. Diatom community structures in terms of molecular and morphological approaches were congruent with 49 shared species. Species from genera Gomphonema, Navicula and Encyonema were less assigned in molecular analysis. The most abundant taxa in the Una River are alkaliphilous, belonging to the genera Gomphonema, Nitzshia and Navicula. Although specific for their extremely good chemical status, the travertine barriers of the Una River are largely inhabited with meso-eutraphentic taxa.

Morphological and genome-wide evidence for natural hybridisation within the genus Stipa (Poaceae)

Hybridisation in the wild between closely related species is a common mechanism of speciation in the plant kingdom and, in particular, in the grass family. Here we explore the potential for natural hybridisation in Stipa (one of the largest genera in Poaceae) between genetically distant species at their distribution edges in Mountains of Central Asia using integrative taxonomy. Our research highlights the applicability of classical morphological and genome reduction approaches in studies on wild plant species. The obtained results revealed a new nothospecies, Stipa × lazkovii, which exhibits intermediate characters to S. krylovii and S. bungeana. A high-density DArTseq assay disclosed that S. × lazkovii is an F1 hybrid, and established that the plastid and mitochondrial DNA was inherited from S. bungeana. In addition, molecular markers detected a hybridisation event between morphologically and genetically distant species S. bungeana and probably S. glareosa. Moreover, our findings demonstrated an uncertainty on the taxonomic status of S. bungeana that currently belongs to the section Leiostipa, but it is genetically closer to S. breviflora from the section Barbatae. Finally, we noticed a discrepancy between the current molecular data with the previous findings on S. capillata and S. sareptana.

Assessing different components of diversity across a river network using eDNA

AbstractAssessing individual components of biodiversity, such as local or regional taxon richness, and differences in community composition is a long‐standing challenge in ecology. It is especially relevant in spatially structured and diverse ecosystems. Environmental DNA (eDNA) has been suggested as a novel technique to detect taxa and therefore may allow to accurately measure biodiversity. However, we do not yet fully understand the comparability of eDNA‐based assessments to classical morphological approaches. We assessed may‐, stone‐, and caddisfly genera with two contemporary methods, namely eDNA sampling followed by molecular identification and kicknet sampling followed by morphological identification. We sampled 61 sites distributed over a large river network, allowing a comparison of various diversity measures from the catchment to site levels and providing insights into how these measures relate to network properties. We extended our data with historical morphological records of total diversity at the catchment level. At the catchment scale, identification based on eDNA and kicknet samples detected similar proportions of the overall and cumulative historically documented richness (gamma diversity), 42% and 46%, respectively. We detected a good overlap (62%) between genera identified from eDNA and kicknet samples at the regional scale. At the local scale, we found highly congruent values of local taxon richness (alpha diversity) between eDNA and kicknet samples. Richness of eDNA was positively related to discharge, a descriptor of network position, while kicknet was not. Beta diversity, a measure of dissimilarity between sites, was comparable for the two contemporary methods and is driven by species replacement and not by nestedness. Although eDNA approaches are still in their infancy and optimization regarding sampling design and laboratory work is still needed, our results indicate that it can capture different components of diversity, proving its potential utility as a new tool for large sampling campaigns across hitherto understudied complete river catchments.

Composition of biological soil crusts from sand dunes of the Baltic Sea coast in the context of an integrative approach to the taxonomy of microalgae and cyanobacteria

ABSTRACT Most of the data on biodiversity, ecology and biogeography of microalgae and cyanobacteria are based on classical morphological approaches. However, morphological identification of these microorganisms is often possible only to higher taxonomic ranks such as genus, because of low morphological diversity and high variability along with the presence of cryptic taxa. This study compared the species composition of cyanobacteria, and green and streptophyte microalgae, isolated from biological soil crusts (BSCs) of maritime sand dunes (Baltic Sea, Germany) and identified through culture-dependent morphological methods combined with molecular phylogenetic data. Phylogenetic analyses (based on SSU rRNA and ITS-1,2 for microalgae, or the SSU-LSU ITS region for cyanobacteria) provided unambiguous identifications of 20 strains (37.7% of all strains investigated) to species level; the identifications had to be corrected after preliminary morphological determination of eight strains. For 27 strains (50.9%), identification with molecular markers was possible only to genus or group of closely related species, because a modern taxonomic revision of these taxa is preliminary, incomplete or non-existent. Identification to genus was problematic for six strains (11.3%). This combination of morphological and molecular methods (integrative approach) resulted in the discovery of rare, taxonomically or ecologically interesting taxa, and in the description of a new species of Tetradesmus (T. arenicola sp. nov.), a new combination for Chlamydomonas callunae (Heterochlamydomonas callunae comb. nov.), epitypification of the rare alga Actinochloris sphaerica and emendation of the recently described Eremochloris sphaerica. A microscopic culture-dependent method and an integrative approach provided similar results concerning the cyanobacterial and algal diversity of BSCs of Baltic sand dunes in general. However, this investigation using an integrative approach allowed us to precisely identify species of several important taxa (the most common and dominant species) in the community structure of BSCs, and also certain rare representatives.

Structure Features and Sensitivity of Hippocampal Cells to the Endothelial Vascular Growth Factor Against the Background of Intranasal Administration of Titanium Dioxide Nanoparticles

The aim:to study the structural characteristics and sensitivity of rat hippocampal cells to the endothelial growth factor of vessels against intranasal administration of nanoparticles (NP) TiO2(rutile form, 40–60 nm, daily, 10 mg/kg animal body weight, 30 days).Material and methods.When studying the effect of the studied NP on the morphological characteristics of the hippocampus, animals of the experimental group were intranasally injected daily with a suspension of NP TiO2(10 mg/kg body weight, 30 days), and the rats of the control group received distilled water in the same volume. Animals were removed from the experiment after 30 days of overdose of diethyl ether and the brain was removed for histological and electron microscopic examination. We used classical morphological approaches, electron microscopy and immunohistochemical staining with antibodies to the cell sensitivity marker, the receptor for endothelial vascular growth factor VEGFR-1 / Flt-1.The classical morphological approaches, the method of electron microscopy and immunohistochemical staining with antibodies to the marker of sensitivity of the receptor cells to the endothelial vascular growth factor VEGFR-1/Flt-1 were used.Results. It has been established that against the background of intranasal administration of NP TiO2in the pyramidal layer of CA1and CA3hippocampal fields, the density of neuronal packing decreases, the area of the nucleus and the pericarion of the cells decrease in comparison with the control. Ultrastructural changes were detected, indicating a damage to the structures of the energy and protein synthesis apparatus of neurons. Immunohistochemical study revealed an increase in the sensitivity of vascular endothelial cells and the hippocampal macroglia of the experimental group of animals to the endothelial factor of vascular growth.Conclusions. Intranasal management of NP TiO2leads to negative changes in the structural characteristics of the CA1, CA3hippocampal zones, ultramicroscopic features, and also to an increase in the sensitivity of a number of cells to VEGF, which indicates their possible neurotoxic effect.

Toxic effect of titanium dioxide nanoparticles on morphological characteristics of thymus

Aim. Study of effects of titanium dioxide nanoparticles administered orally on the rodent thymus morphological and functional state. Methods. The study used classical morphological approaches and specific markers of proliferation - Ki-67, apoptosis - p53 protein and macrophages - CD68, which allow adequately identifying not only the cells themselves, but also their functional state. The rodent thymus was analyzed after oral administration (10 mg/kg of body weight of the animal, 28 days) of the TiO2 nanoparticles (rutile form, 40-60 nm) obtained by diluting the TiO2 powder in distilled water. Aggregation of the nanoparticles was prevented by processing a suspension of nanodispersed TiO2 in an ultrasonic bath. The rats of the control group were orally injected with distilled water in the same volume. Serial paraffin sections of the thymus were stained with hematoxylin-eosin, picrofuxin according to Van Gieson, immunohistochemical staining was performed with antibodies to Ki-67, CD68, p53. Results. Significant changes of the tissue of thymus gland under the influence of TiO2 nanoparticles were revealed. In the thymus of experimental animals, a decrease in the proportion of cortex was found to be 17.6 %, a significant decrease in the density of the cell population due to decrease in the number of thymocytes was demonstrated. Immunohistochemical typing revealed that under the influence of TiO2 nanoparticles, a decrease in the number of Ki-67-positive cells in the cortex of the lobule of the thymus gland was observed, which indicates the inhibition of proliferation in these conditions. Under the influence of TiO2 nanoparticles, an increase of the amount of cells entering apoptosis in the cortex of the thymus segment of the experimental group by 5.18 times was observed, as evidenced by the results of immunohistochemical study of the expression of apoptosis marker p53 protein. Perhaps, as a compensatory mechanism there is a pronounced increase in the number of macrophages, as indicated by an increase in the average number of CD68 immunopositive cells in the cortex of the thymus of the test group by 2.61, and in the brain substance by 1.35. Conclusion. The revealed morphological and functional changes of the thymus with oral administration of TiO2 nanoparticles indicate their immunosuppressive effect.

Hundreds of genetic barcodes of the species-rich hydroid superfamily Plumularioidea (Cnidaria, Medusozoa) provide a guide toward more reliable taxonomy

Marine hydroids are important benthic components of shallow and deep waters worldwide, but their taxonomy is controversial because diagnostic morphological characters to categorize taxa are limited. Their genetic relationships are also little investigated. We tested taxonomic hypotheses within the highly speciose superfamily Plumularioidea by integrating a classical morphological approach with DNA barcoding of the 16S and COI mitochondrial markers for 659 and 196 specimens of Plumularioidea, respectively. Adding Genbank sequences, we inferred systematic relationships among 1,114 plumularioids, corresponding to 123 nominal species and 17 novel morphospecies in five families of Plumularioidea. We found considerable inconsistencies in the systematics of nominal families, genera and species. The families Kirchenpaueriidae and Plumulariidae were polyphyletic and the Halopterididae paraphyletic. Most genera of Plumularioidea are not monophyletic. Species diversity is considerably underestimated. Within our study, at least 10% of the morphologically-distinctive morphospecies are undescribed, and about 40% of the overall species richness is represented by cryptic species. Convergent evolution and morphological plasticity therefore blur systematic relationships. Additionally, cryptic taxa occur frequently in sympatry or parapatry, complicating correspondence with type material of described species. Sometimes conspecificity of different morphotypes was found. The taxonomy of hydroids requires continued comprehensive revision.

Bionomic aspects of Lutzomyia evansi and Lutzomyia longipalpis, proven vectors of Leishmania infantum in an endemic area of non-ulcerative cutaneous leishmaniasis in Honduras

BackgroundSome Lutzomyia species are the vectors of human leishmaniasis in the Americas. Visceral and cutaneous leishmaniasis are both endemic in the Pacific region of Honduras, but the non-ulcerative form is the more frequent clinical manifestation in this region, where Lutzomyia longipalpis is the most abundant and the only incriminated vector. Taxonomic identification and distribution studies of sand flies are important to understand the epidemiology and to control these neglected tropical diseases.ResultsHere, we identified more than 13,000 Lutzomyia specimens captured in Isla del Tigre, Honduras, through a classical morphological approach. The two most common species were Lutzomyia evansi and Lu. longipalpis, and this is the first report of three Lutzomyia species on this island. The blood meal source was successfully identified for five sand fly species. A barcode analysis using the cox1 mitochondrial marker proved to be effective in discriminating between species and seems to be a valuable tool for future epidemiological studies including a wider geographical area.ConclusionThis study updates the diversity and blood meal sources of Lutzomyia species in an island endemic for non-ulcerative cutaneous leishmaniasis in the Pacific region of Honduras, and determines the effectiveness of the barcoding approach to discriminate species, as a complementary tool to classical morphology.

On the chromatin of the immature oocyte: from morphology to function and regulatory mechanisms mediated by follicular cells

In her comment entitled ‘Nuclear histochemistry: its history in fifty volumes’ (Eur J Histochem 2006; 50:79-81) Maria Gabriella Manfredi Romanini referred to “nuclear histochemistry” as a “real molecular biology in situ, applied to research on dynamic processes in the nucleus, which makes the microscopic and histochemical approach absolutely irreplaceable for the progress of our understanding of cell biology”. These words perfectly exemplify the research path that is elucidating the process of remodeling of chromatin configuration within the nucleus of the mammalian oocyte. This process, which occurs towards the end of the oocyte differentiation phase before meiotic resumption, has received much attention in the last decade since it has a tremendous impact on the capability of the oocyte to generate an embryo after fertilization. The study of the oocyte chromatin by means of classical morphological and histochemical approaches has given a fundamental contribution to our understanding of oocyte biology and has paved the way to functional and mechanistic studies. Several research groups worldwide, including ours, are indeed dedicating a large amount of studies to find the relationship between morphological and functional aspects of the oocyte chromatin remodeling process, to reveal the molecular mechanisms involved, as well as to clarify the contribution of the follicular compartment. Here, we summarize some studies intended to give insight into the mechanism( s) regulating this complex process, including recent findings indicating that ovarian granulosa cells and their coupling with the oocyte through gap junctions are implicated in such a process.

DNA barcoding the genus Chara: molecular evidence recovers fewer taxa than the classical morphological approach.

Charophytes (Charales) are benthic algae with a complex morphology. They are vulnerable to ecosystem changes, such as eutrophication, and are red-listed in many countries. Accurate identification of Chara species is critical for understanding their diversity and for documenting changes in species distribution. Species delineation is, however, complicated, because of high phenotypic plasticity. We used barcodes of the ITS2, matK and rbcL regions to test if the distribution of barcode haplotypes among individuals is consistent with species boundaries as they are currently understood. The study included freshly collected and herbarium material of 91 specimens from 10 European countries, Canada and Argentina. Results showed that herbarium specimens are useful as a source of material for genetic analyses for aquatic plants like Chara. rbcL and matK had highest sequence recoverability, but rbcL had a somewhat lower discriminatory power than ITS2 and matK. The tree resulting from the concatenated data matrix grouped the samples into six main groups contrary to a traditional morphological approach that consisted of 14 different taxa. A large unresolved group consisted of C.intermedia, C.hispida, C.horrida, C.baltica, C.polyacantha, C.rudis, C.aculeolata, and C.corfuensis. A second unresolved group consisted of C.virgata and C.strigosa. The taxa within each of the unresolved groups shared identical barcode sequences on the 977 positions of the concatenated data matrix. The morphological differences of taxa within both unresolved groups include the number and length of spine cells, stipulodes, and bract cells. We suggest that these morphological traits have less taxonomic relevance than hitherto assumed.

Metabolomics as a potential chemotaxonomical tool: application in the genus Vernonia schreb.

The taxonomic classification of the genus Vernonia Schreb is complex and, as yet, unclear. We here report the use of untargeted metabolomics approaches, followed by multivariate analyses methods and a phytochemical characterization of ten Vernonia species. Metabolic fingerprints were obtained by accurate mass measurements and used to determine the phytochemical similarities and differences between species through multivariate analyses approaches. Principal component analysis based on the relative levels of 528 metabolites, indicated that the ten species could be clustered into four groups. Thereby, V. polyanthes was the only species with presence of flavones chrysoeriol-7-O-glycuronyl, acacetin-7-O-glycuronyl and sesquiterpenes lactones piptocarphin A and piptocarphin B, while glaucolide A was detected in both V. brasiliana and V. polyanthes, separating these species from the two other species of the Vernonanthura group. Species from the Lessingianthus group were unique in showing a positive response in the foam test, suggesting the presence of saponins, which could be confirmed by metabolite annotation. V. rufogrisea showed a great variety of sesquiterpene lactones, placing this species into a separate group. Species within the Chrysolaena group were unique in accumulating clovamide. Our results of LC-MS-based profiling combined with multivariate analyses suggest that metabolomics approaches, such as untargeted LC-MS, may be potentially used as a large-scale chemotaxonomical tool, in addition to classical morphological and cytotaxonomical approaches, in order to facilitate taxonomical classifications.

Polystichum montevidenseDemystified: Molecular and Morphological Data Reveal a Cohesive, Widespread South American Species

The genus Polystichum presents striking variation in morphology and habitat preference in the Central Andes, the Serra do Mar, and adjacent regions. Among these taxa, Polystichum montevidense is a name long applied to an array of twice-pinnate species with dark petiole scales, broad leaves, and no vegetative propagules. Using a classical morphological approach combined with inferences gleaned from molecular data, we analyzed P. montevidense and its widespread and ecologically prominent array of allies. Results from our combined molecular and morphological analysis suggest the name P. montevidense should be applied to collections from the Central Andes south to Argentina, and east to Uruguay and the southernmost portion of Brazil. Most Brazilian plants determined as P. montevidense in herbaria are P. platylepis.

Evolutionary geographic relationships among orthocladine chironomid midges from maritime Antarctic and sub-Antarctic islands

Two species of chironomid midges are currently described in the genus Belgica Jacobs, 1900. Belgica antarctica Jacobs, 1900 is endemic to parts of the maritime Antarctic, and Belgica albipes (Seguy, 1965) is endemic to Iles Crozet, a sub-Antarctic archipelago in the southern Indian Ocean. The relationships between these species, and their closest known relative (Eretmoptera murphyi Schaeffer, 1914, endemic to sub-Antarctic South Georgia), were examined by sequencing DNA fragments for domains 1 and 3–5 of 28S ribosomal DNA and the mitochondrial gene cytochrome c oxidase 1 (cox1). The resulting molecular relationships between the three species were unclear, although their position within the subfamily Orthocladiinae of the Chironomidae, as generated by classical taxonomy, was confirmed. Our data reinforce earlier doubts, based on classical morphological approaches, that the generic placement of E. murphyi may be incorrect. Further analyses may indeed confirm that the species represents a third member of the genus Belgica. Genetic distance analysis, limited to the barcode region of cox1, indicated high differentiation between the two populations of B. albipes sampled (one obtained from the type location), suggesting the likely presence of cryptic species within this taxon, and that the taxonomic status of this species should be revised. Analysis of cox1 sequences in B. antarctica highlighted a strong genetic structure between populations obtained from 12 locations along the Antarctic Peninsula and the South Shetland Islands archipelago, with a number of distinctive mtDNA lineages inhabiting geographically distinct areas. In particular, we found four different haplogroups constituting geographically close but genetically distinct populations, a pattern likely to have been encouraged by the brachyptery of the members of this genus. We suggest that the different genetic patterns shown by each haplogroup have probably been determined by historical dispersal and colonization events during the Pleistocene, and are consistent with their survival in refuges in situ during successive glacial maxima over this period.

Nematode community populations in the rhizosphere of cultivated olive differs according to the plant genotype

Classical and molecular methods were used to study the nematode communities associated with rhizosphere soil and roots of a collection of 16 olive cultivars from a world olive germplasm bank in Mengibar (Jaen province, southern Spain). Classical nematological analysis, including soil nematode extraction, species counting and morphological identification showed that 24 taxa belonging to 9 genera (including Aphelenchoides, Criconemoides, Ditylenchus, Filenchus, Helicotylenchus, Merlinius, Paratylenchus, Tylenchus, and Xiphinema) and 8 families (including Anguinidae, Aphelenchidae, Belonolaimidae, Criconematidae, Hoplolaimidae, Longidoridae, Tylenchidae and Tylenchulidae) of plant-parasitic nematodes were present, with one species (Helicotylenchus digonicus) being prevalent in all samples. The low values of the plant-parasitic nematode index (PPI) indicated a high disturbance of the field soil probably due to application of herbicides and fertilizers. Cluster analysis of population densities of the various nematode species, nematode trophic groups, and ecological indices grouped most olive cultivars into three main clusters indicating that olive genotypes differ in the nematode communities in their rhizosphere soil. The use of T-RFLP analysis discriminated to a higher extent the nematode communities present in the rhizosphere soil from the different olive cultivars as compared to the morphological-based analysis. This study provides the first evidence of an effect of the olive genotype on nematode community composition by combining classical morphological and molecular approaches.

Systematic revision of the genus Cerocoma Geoffroy, 1762 (Coleoptera: Meloidae: Cerocomini)

The taxonomy of the Palaearctic genus Cerocoma is revised using a classical morphological approach. A catalogue to species with current synonyms, type information and repositories is provided as well as diagnostic keys to species (male and female) and subspecies (only male), illustrations of male dimorphic and diagnostic characters and detailed distribution data, including literature and collection records. The biology of Cerocoma is summarised, based on available literature and original field observations. Three new species are described and figured: Cerocoma confusa sp.n. (= C. syriaca Auctorum), C. longiseta sp.n. and C. martae sp.n. New status is assessed for two taxa: C. latreillei sterbai stat.n. and C. marginiventris stat.n. New synonymies are proposed as follows: C. syriaca Abeille de Perrin, 1880 = C. barthelemyi Baudi, 1878 syn. nov.; C. latreillei schah Kaszab, 1968 = C. latreillei sterbai Mařan, 1944 syn. nov.; C. scovitzi mirabilis Dvořák, 1993 = C. scovitzi intermedia Mařan, 1944 syn. nov. Adult morphological characters and molecular datasets (nuclear ITS2 and mitochondrial 16S) are used, separately and combined, to carry out the first attempt to elucidate the Cerocoma phylogeny, using Maximum Parsimony and Bayesian Inference. The resulted phylogeny supports the arrangement of Cerocoma into five subgenera: Cerocomina, Mesocerocoma and Metacerocoma as previously defined; the nominate subgenus, restricted to the species group of C. schaefferi Linnaeus, 1758; and Meloides Piller & Mitterpacher, 1783, recently resurrected on morphological data only.