Sebacinales are common mycorrhizal associates of Ericaceae

Previous reports of sequences of Sebacinales (basal Hymenomycetes) from ericoid mycorrhizas raised the question as to whether Sebacinales are common mycorrhizal associates of Ericaceae, which are usually considered to associate with ascomycetes. Here, we sampled 239 mycorrhizas from 36 ericoid mycorrhizal species across the world (Vaccinioideae and Ericoideae) and 361 mycorrhizas from four species of basal Ericaceae lineages (Arbutoideae and Monotropoideae) that do not form ericoid mycorrhizas, but ectendomycorrhizas. Sebacinales were detected using sebacinoid-specific primers for nuclear 28S ribosomal DNA, and some samples were investigated by transmission electron microscopy (TEM). Diverging Sebacinales sequences were recovered from 76 ericoid mycorrhizas, all belonging to Sebacinales clade B. Indeed, some intracellular hyphal coils had ultrastructural TEM features expected for Sebacinales, and occurred in living cells. Sebacinales belonging to clade A were found on 13 investigated roots of the basal Ericaceae, and TEM revealed typical ectendomycorrhizal structures. Basal Ericaceae lineages thus form ectendomycorrhizas with clade A Sebacinales, a clade that also harbours ectomycorrhizal fungi. This further supports the proposition that Ericaceae ectendomycorrhizas involve ectomycorrhizal fungal taxa. When ericoid mycorrhizas evolved secondarily in Ericaceae, a shift of mycobionts occurred to ascomycetes and clade B Sebacinales, hitherto not described as ericoid mycorrhizal fungi.     

On the phylogenetic positions of the Caryophyllidea, Pseudophyllidea and Proteocephalidea (Eucestoda) inferred from 18S rRNA

A phylogenetic analysis of tapeworms (Eucestoda) based on complete sequences of the 18S rRNA genes of 43 taxa (including new sequences of 12 species) was carried out, with the emphasis on the groups parasitising teleost fish and reptiles. Spathebothriidea and Trypanorhyncha (the latter group being paraphyletic) appeared as basal groups of the Eucestoda but their position was not stable. The tetrafossate orders (Litobothriidea, Lecanicephalidea, Tetraphyllidea, Proteocephalidea, Nippotaeniidea, Tetrabothriidea and Cyclophyllidea) were well separated from the remaining groups. Results supported polyphyly of the Pseudophyllidea formed by two distinct clades: one with diphyllobothriids (Diphyllobothrium, Schistocephalus, Spirometra and Duthiersia) and another including Abothrium, Probothriocephalus, Eubothrium and Bothriocephalus. The former pseudophyllidean clade formed a separate branch with the Caryophyllidea (Khawia and Hunterella) and Haplobothriidea (Haplobothrium), the latter taxon being closely related to either caryophyllideans or diphyllobothriids in different analyses. Proteocephalideans formed a monophyletic group in all analyses and constituted a clade within the Tetraphyllidea thus rendered paraphyletic. Within the Proteocephalidea, the Acanthotaeniinae (Acanthotaenia from reptiles in Africa) and Gangesiinae (Gangesia and Silurotaenia from silurid fish in the Palearctic Region) were separated from parasites of freshwater fish and mammals. The family Proteocephalidae was found to be paraphyletic due to the placement of a monticelliid species, Monticellia sp., in a clade within the former family. The genus Proteocephalus appeared as an artificial assemblage of unrelated taxa which is congruent with previous molecular analyses.     

Infrafamilial Phylogeny of the Aquatic Angiosperm Podostemaceae Inferred from the Nucleotide Sequences of the matK Gene

Abstract: The infrafamilial relationships of Podostemaceae were deduced from nucleotide sequences of the chloroplast matK gene. The matK phylogenetic analyses show that Podostemaceae are composed of two major clades that correspond to the subfamily Tristichoideae sensu stricto and Weddellina and the subfamily Podostemoideae. Weddellina, which has long been recognized as a member of the Tristichoideae, is sister to the Podostemoideae, supporting the classification that recognized a third subfamily Weddellinoideae. Malaccotristicha malayana and Terniopsis sessilis form a basal clade in Tristichoideae sensu stricto. Tristichoideae show a high morphological diversity and, surprisingly, a close relationship exists between Dalzellia zeylanica and Indotristicha ramosissima, which remarkably differ in their body plans. A few genera defined by particular characters, such as Synstylis and Torrenticola, merge into clades of other larger genera. The Podostemoideae taxa studied are composed of two American clades, an Asian-Australian clade and a Madagascan clade, and may suggest that the subfamily perhaps originated in America and migrated to the Old World.     

Leave it to the leaves: a molecular phylogenetic study of Malaxideae (Epidendroideae, Orchidaceae)

Nuclear ITS and plastid matK sequences were collected for 71 taxa of Malaxideae (Orchidaceae). Resulting cladograms are highly resolved and well supported by jackknife analyses. These indicate that the traditional classification system of the tribe using characters primarily related to floral morphology does not reflect the evolutionary history of these taxa. Rather, the tribe is split into two major clades: one of terrestrial species and another of epiphytes. Within the epiphytic clade, taxa with laterally compressed leaves (Oberonia) are monophyletic, whereas the remaining taxa (Liparis pro parte) have elongate conduplicate leaves and form a paraphyletic grade of at least two additional monophyletic lineages. Within the terrestrial clade, taxa with plicate leaves (Liparis p.p. and Malaxis p.p.) clearly separate from taxa with conduplicate leaves (Liparis p.p. and Malaxis p.p.). Although further taxon sampling should take place before nomenclature is changed, it seems evident that Malaxideae will need to be divided into at least seven genera. Furthermore, the transition from epiphytic to terrestrial habit is documented to have occurred only once in Malaxideae, and the value of vegetative over reproductive features in classifying some groups of orchids is again demonstrated.     

Phylogenetic analyses of "higher" Hamamelididae based on plastid sequence data

Phylogenetic relationships were examined within the "higher" Hamamelididae using 21 species representing eight families and related outgroups. Chloroplast DNA sequences encoding the matK gene (/1 kilobase) provided 258 informative nucleotide sites. Phylogenetic analysis of this variation produced one most parsimonious tree supporting three monophyletic groups. In this tree, Nothofagus was basal to a well supported clade of remaining "higher" hamamelids, in which Fagaceae, including Fagus, were sister to a clade of core "higher" hamamelids that share wind-pollination, bicarpellate flowers, granular pollen walls, and reduced pollen apertures. Within the core "higher" hamamelids three subclades were resolved, Myricaceae, (Casuarina-(Ticodendron-(Betulaceae))), and (Rhoiptelea-Juglandaceae). Each subclade was well supported but relationships among them were not. The basal position of Nothofagus within the matK tree is consistent with the fossil record of "higher" hamamelids in which Nothofagus pollen appears earlier than microfossils with affinities to other modern "higher" hamamelids. This placement supports the exclusion of Nothofagus from Fagaceae and suggests two hypotheses for the origin of the cupule. The cupule may be ancestral within "higher" hamamelids and subsequently lost in core members of the clade or there may have been two independent origins. It is suggested that the three clades (1) Nothofagaceae, (2) Fagaceae, and (3) Juglandaceae, Rhoiptelea, Myricaceae, Casuarina, Ticodendron, and Betulaceae be considered at the ordinal level and that traditional orders, such as Fagales sensu Cronquist (Fagaceae, Nothofagaceae, and Betulaceae) be abandoned. Comparative analyses of matK sequences with previously published rbcL sequences demonstrate that for the taxa considered here matK sequences produced trees with greater phylogenetic resolution and a higher consistency index.     

Anatomy and ultrastructure of mycorrhizal associations of neotropical Ericaceae

Ericaceae are obligatory associated with symbiotic fungi forming several, distinctive categories of mycorrhizas. While ericoid, arbutoid, and monotropoid mycorrhizas are known since many years from ericads of the northern hemisphere and the ericoid mycorrhiza also from Australia, a further mycorrhizal category with hyphal sheath, Hartig net, and intracellular colonization was described by us recently and termed cavendishioid mycorrhiza because it was found on Cavendishia nobilis, a species belonging to the Andean clade (Vaccinioideae) of Ericaceae. As the previous findings indicated a correlation between the mycorrhizal category and the systematic position of Ericaceae, we tested the hypothesis that other ericads of the Andean clade might also form cavendishioid mycorrhizas, while ericads occurring in the same area but not belonging to the Andean clade might not. Mycorrhizas of 20 different ericaceous species, 15 belonging to the Andean clade and 5 to other Vaccinioideae or Ericoideae, were sampled in the tropical mountain rain forest area of South Ecuador and investigated by light and electron microscopy. All the 15 members of the Andean clade ericads displayed a hyphal sheath, as well as inter- and intracellular colonization by hyphae as was found on Cavendishia previously. The five species not belonging to the Andean clade ericads displayed only intracellular colonization by hyphae and hence were typical ericoid mycorrhizal. Ultrastructural studies revealed Sebacinales and ascomycetes as mycorrhiza formers in both associations even within one single cell. The results thus support the hypothesis that the Andean clade of Ericaceae forms mycorrhizas distinct from the arbutoid category and most likely presents an independent evolutionary line in the Ericaceae derived from the ericoid mycorrhizas, justifying the new term “cavendishioid mycorrhiza”.     

Phylogenetic relationships and divergence times among mustelids (Mammalia: Carnivora) based on nucleotide sequences of the nuclear interphotoreceptor retinoid binding protein and mitochondrial cytochrome b genes

Phylogenetic relationships among 20 species-group taxa of Mustelidae, representing Mustelinae (Mustela, Martes, Gulo), Lutrinae (Enhydra), and Melinae (Meles), were examined using nucleotide sequences of the nuclear interphotoreceptor retinoid binding protein (IRBP) and mitochondrial cytochrome b genes. Neighbor-joining and maximum-parsimony phylogenetic analyses on these genes separately and combined were conducted. While IRBP performed better than cytochrome b in recovering more-inclusive clades, cytochrome b demonstrated more resolving power in recovering less-inclusive clades. Strong support was found for a close affinity of Enhydra with Mustela to the exclusion of Martes and Gulo (causing Mustelinae to be paraphyletic); the most-basal position of Mustela vison within Mustela, followed by Mustela erminea; an association of Mustela lutreola, Mustela itatsi, Mustela sibirica, and the subgenus Putorius (including Mustela putorius and Mustela eversmanii), to the exclusion of Mustela nivalis and Mustela altaica; and a basal position of Mustela itatsi to a clade containing Mustela sibirica and Putorius. Whereas cytochrome b strongly supported Mustela lutreola as the sister species to Putorius, IRBP strongly supported its basal placement to the Mustela itatsi-Mustela sibirica-Putorius clade. The low level of sequence divergence in cytochrome b between Mustela lutreola and Putorius is therefore a result of interspecific mitochondrial introgression between these taxa, rather than a recent origin of Mustela lutreola in a close relationship to Putorius. Time estimates inferred from IRBP and cytochrome b for mustelid divergence events are mostly in agreement with the fossil record.     

Molecular systematics of Malpighiaceae: evidence from plastid rbcL and matK sequences

Phylogenetic analyses of DNA nucleotide sequences from the plastid genes rbcL and matK were employed to investigate intergeneric relationships within Malpighiaceae. Cladistic relationships generated from the independent data matrices for the family are generally in agreement with those from the combined matrix. At the base of Malpighiaceae are several clades mostly representing genera from a paraphyletic subfamily Byrsonimoideae. Intergeneric relationships among these byrsonimoid malpighs are well supported by the bootstrap, and the tribe Galphimeae is monophyletic. There is also a well-supported clade of genera corresponding to tribes Banisterieae plus Gaudichaudieae present in all trees, and many of the relationships among these banisterioid malpighs are well supported by the bootstrap. However, tribes Hiraeae and Tricomarieae (the hiraeoid malpighs) are paraphyletic and largely unresolved. Species of Mascagnia are distributed throughout these hiraeoid clades, confirming the suspected polyphyly of this large genus. Optimization of selected morphological characters on these trees demonstrates clear phylogenetic trends such as the evolution of globally symmetrical from radially symmetrical pollen, increased modification and sterilization of stamens, and switch from base chromosome number n = 6 to n = 10.     

Phylogenetic relationships of Cornaceae and close relatives inferred from matK and rbcL sequences

Phylogenetic relationships were inferred using nucleotide sequences of the chloroplast gene matK for members of Cornales, a well-supported monophyletic group comprising Cornaceae and close relatives. The shortest trees resulting from this analysis were highly concordant with those based on previous phylogenetic analysis of rbcL sequences. Analysis of a combined matK and rbcL sequence data set (a total of 2652 bp [base pairs]) provided greater resolution of relationships and higher internal support for clades compared to the individual data sets. Four major clades (most inclusive monophyletic groups) of Cornales are indicated by both sets of genes: (1) Cornus-Alangium, (2) nyssoids (Nyssa-Davidia-Camptotheca)- mastixioids (Mastixia, Diplopanax), (3) Curtisia, and (4) Hydrangeaceae-Loasaceae. The combined evidence indicates that clades 2 and 3 are sisters, with clade 4 sister to the remainder of Cornales. These relationships are also supported by other lines of evidence, including synapomorphies in fruit and pollen morphology and gynoecial vasculature. Comparisons of matK and rbcL sequences based on one of the most parsimonious rbcL-matK trees indicate that matK has a much higher A-T content (66.9% in matK vs. 55.8% in rbcL) and a lower transition:transversion ratio (1.23 in matK vs. 2.21 in rbcL). The total number of nucleotide substitutions per site for matK is 2.1 times that of rbcL in Cornales. These findings are similar to recent comparisons of matK and rbcL in other dicots. Variable sites of matK are almost evenly distributed among the three codon positions (1.0:1.0:1.3), whereas variable sites of rbcL are mostly at the third position (1.8:1.0 :7.5). Among- lineages rates of nucleotide substitutions in rbcL are basically homogeneous throughout Cornales, but are more heterogeneous in matK.     

Molecular phylogenetics of Caryophyllales based on nuclear 18S rDNA and plastid rbcL, atpB, and matK DNA sequences

To study the inter- and infrafamilial phylogenetic relationships in the order Caryophyllales sensu lato (s.l.), ～930 base pairs of the matK plastid gene have been sequenced and analyzed for 127 taxa. In addition, these sequences have been combined with the rbcL plastid gene for 53 taxa and with the rbcL and atpB plastid genes as well as the nuclear 18S rDNA for 26 taxa to provide increased support for deeper branches. The red pigments of Corbichonia, Lophiocarpus, and Sarcobatus have been tested and shown to belong to the betacyanin class of compounds. Most taxa of the order are clearly grouped into two main clades (i.e., "core" and "noncore" Caryophyllales) which are, in turn, divided into well-defined subunits. Phytolaccaceae and Molluginaceae are polyphyletic, and Portulacaceae are paraphyletic, whereas Agdestidaceae, Barbeuiaceae, Petiveriaceae, and Sarcobataceae should be given familial recognition. Two additional lineages are potentially appropriate to be elevated to the family level in the future: the genera Lophiocarpus and Corbichonia form a well-supported clade on the basis of molecular and chemical evidence, and Limeum appears to be separated from other Molluginaceae based on both molecular and ultrastructural data.     

Phylogenetic relationships of North American garter snakes (Thamnophis) based on four mitochondrial genes: how much DNA sequence is enough?

The clade of garter snakes (Thamnophis) includes some of the most abundant and well-studied snakes in North America. However, phylogenetic relationships within this group have been little studied. We used DNA sequences of four mitochondrial genes (cytochrome b and NADH dehydrogenase subunits 1, 2, and 4) to estimate relationships among 29 of the 31 recognized species of Thamnophis plus the related species Adelophis foxi. Both maximum parsimony (MP) and maximum-likelihood (ML) analyses of all these genes combined produced well-resolved trees with moderate (70-89%) to strong (90-100%) bootstrap support for most clades. MP and ML trees were very similar, with no strongly supported conflict between the two analyses. These analyses identify a clade of 12 species largely restricted to México (the "Mexican clade"), and a clade containing 15 species that collectively range from Central America to southern Canada (the "widespread clade"). These two groups are identified as sister taxa in both MP and ML analyses. A clade consisting of the ribbon snakes (T. sauritus and T. proximus) and the common garter snake (T. sirtalis) is placed as the sister group to all other Thamnophis (i.e., the Mexican + widespread clades) in our analyses. High bootstrap proportions at several levels in the tree support the inclusion of both Thamnophis validus, which has traditionally been placed in the genus Nerodia, and the poorly known species Adelophis foxi within Thamnophis. We used randomly sampled characters (i.e., standard bootstrapping) and randomly sampled contiguous blocks of characters to examine the effect of number of characters on resolution of and support for relationships within Thamnophis using MP. In general, these analyses indicate that we have reached a point of strongly diminishing returns with respect to the effect of adding mtDNA sequence characters for the current set of taxa; our sample of 3809 mtDNA characters is apparently "enough." The next steps to improve the phylogenetic estimate may be to add nuclear DNA sequences, morphology, or behavior, or to sequence additional mtDNA lineages within species.     

Ribosomal RNA genes challenge the monophyly of the Hyalospheniidae (Amoebozoa: Arcellinida)

To date only five partial and two complete SSU rRNA gene sequences are available for the lobose testate amoebae (Arcellinida). Consequently, the phylogenetic relationships among taxa and the definition of species are still largely dependant on morphological characters of uncertain value, which causes confusion in the phylogeny, taxonomy and the debate on cosmopolitanism of free-living protists. Here we present a SSU rRNA-based phylogeny of the Hyalospheniidae including the most common species. Similar to the filose testate amoebae of the order Euglyphida the most basal clades have a terminal aperture; the ventral position of the pseudostome appears to be a derived character. Family Hyalospheniidae appears paraphyletic and is separated into three clades: (1) Heleopera sphagni, (2) Heleopera rosea and Argynnia dentistoma and (3) the rest of the species from genera Apodera, Hyalosphenia, Porosia and Nebela. Our data support the validity of morphological characters used to define species among the Hyalospheniidae and even suggest that taxa described as varieties may deserve the rank of species (e.g. N. penardiana var. minor). Finally our results suggest that the genera Hyalosphenia and Nebela are paraphyletic, and that Porosia bigibbosa branches inside the main Nebela clade.     

Phylogenetic relationships and evolution of Crassulaceae inferred from matK sequence data

Chloroplast gene matK sequence data were used to estimate the phylogeny of 112 species of Crassulaceae sampled from 33 genera and all six recognized subfamilies. Our analyses suggest that five of six subfamilies recognized in the most recent comprehensive classification of the family are not monophyletic. Instead, we recovered a basal split in Crassulaceae between the southern African CRASSULA: clade (Crassuloideae) and the rest of the family (Sedoideae). These results are compatible with recent studies of cpDNA restriction site analyses. Within Sedoideae, four subclades were also recovered: KALANCHOE:, Leucosedum, Acre, and AEONIUM:; evidence also exists for a TELEPHIUM: clade and SEMPERVIVUM: clade. The genus SEDUM: is highly polyphyletic with representatives spread throughout the large Sedoideae clade. Sympetaly and polymerous flowers have arisen multiple times in Crassulaceae and thus are not appropriate characters upon which to base subfamilial limits, as has been done in the past. One floral character, haplostemy, appears to be confined to the well-supported CRASSULA: clade. Our analyses suggest a southern African origin of the family, with subsequent dispersal northward into the Mediterranean region. From there, the family spread to Asia/eastern Europe and northern Europe; two separate lineages of European Crassulaceae subsequently dispersed to North America and underwent substantial diversification. Our analyses also suggest that the original base chromosome number in Crassulaceae is x = 8 and that polyploidy has played an important role in seven clades. Three of these clades are exclusively polyploid (SEMPERVIVUM: clade and two subclades within the KALANCHOE: and AEONIUM: clades), whereas four (Crassula, Telephium, Leucosedum, and ACRE: clades) comprise both diploid and polyploid taxa. Polyploidy is particularly rampant and cytological evolution especially complex in the ACRE: clade.     

Ultrastructural and phylogenetic studies on Blastocystis isolates from cockroaches

Four Blastocystis isolates from cockroaches were established and these isolates were morphologically confirmed as Blastocystis organisms by light and/or electron microscopy. As these isolates were morphologically indistinguishable from Blastocystis isolated from other animals, phylogenetic analyses were conducted using their small subunit ribosomal RNA genes. A analyses of these sequences with previously reported ones that had been classified into nine Blastocystis clades indicated the presence of a new clade that comprised only Blastocystis organisms from cockroaches (clade X). A clade comprised of amphibian and reptilian Blastocystis organisms (clade IX) was located at the basal position of the Blastocystis tree together with the common ancestor of Proteromonas and Protoopalina, clade X emerged after the divergences of these two basal clades and its branching position was clearly supported by bootstrap analysis.     

Molecular phylogeny of the Blastocladiomycota (Fungi) based on nuclear ribosomal DNA

The Blastocladiomycota is a recently described phylum of ecologically diverse zoosporic fungi whose species have not been thoroughly sampled and placed within a molecular phylogeny. In this study, we investigated the phylogeny of the Blastocladiomycota based on ribosomal DNA sequences from strains identified by traditional morphological and ultrastructural characters. Our results support the monophyly of the Coelomomycetaceae and Physodermataceae but the Blastocladiaceae and Catenariaceae are paraphyletic or polyphyletic. The data support two clades within Allomyces with strains identified as Allomyces arbusculus in both clades, suggesting that species concepts in Allomyces are in need of revision. A clade of Catenaria species isolated from midge larvae group separately from other Catenaria species, suggesting that this genus may need revision. In the Physodermataceae, Urophlyctis species cluster with a clade of Physoderma species. The algal parasite Paraphysoderma sedebokerensis nom. prov. clusters sister to other taxa in the Physodermataceae. Catenomyces persicinus, which has been classified in the Catenariaceae, groups with the Chytridiomycota rather than Blastocladiomycota. The rDNA operon seems to be suitable for classification within the Blastocladiomycota and distinguishes among genera; however, this region alone is not suitable to determine the position of the Blastocladiomycota among other basal fungal phyla with statistical support. A focused effort to find and isolate, or directly amplify DNA from additional taxa will be necessary to evaluate diversity in this phylum. We provide this rDNA phylogeny as a preliminary framework to guide further taxon and gene sampling and to facilitate future ecological, morphological, and systematic studies.     

Phylogeny reconstruction in the Caesalpinieae grade (Leguminosae) based on duplicated copies of the sucrose synthase gene and plastid markers

The Caesalpinieae grade (Leguminosae) forms a morphologically and ecologically diverse group of mostly tropical tree species with a complex evolutionary history. This grade comprises several distinct lineages, but the exact delimitation of the group relative to subfamily Mimosoideae and other members of subfamily Caesalpinioideae, as well as phylogenetic relationships among the lineages are uncertain. With the aim of better resolving phylogenetic relationships within the Caesalpinieae grade, we investigated the utility of several nuclear markers developed from genomic studies in the Papilionoideae. We cloned and sequenced the low copy nuclear gene sucrose synthase (SUSY) and combined the data with plastid trnL and matK sequences. SUSY has two paralogs in the Caesalpinieae grade and in the Mimosoideae, but occurs as a single copy in all other legumes tested. Bayesian and maximum likelihood phylogenetic analyses suggest the two nuclear markers are congruent with plastid DNA data. The Caesalpinieae grade is divided into four well-supported clades (Cassia, Caesalpinia, Tachigali and Peltophorum clades), a poorly supported clade of Dimorphandra Group genera, and two paraphyletic groups, one with other Dimorphandra Group genera and the other comprising genera previously recognized as the Umtiza clade. A selection analysis of the paralogs, using selection models from PAML, suggests that SUSY genes are subjected to a purifying selection. One of the SUSY paralogs, under slightly stronger positive selection, may be undergoing subfunctionalization. The low copy SUSY gene is useful for phylogeny reconstruction in the Caesalpinieae despite the presence of duplicate copies. This study confirms that the Caesalpinieae grade is an artificial group, and highlights the need for further analyses of lineages at the base of the Mimosoideae.     

Phylogenetic relationships of russuloid basidiomycetes with emphasis on aphyllophoralean taxa

Many homobasidiomycetes are characterized by a combination of gloeocystidia and amyloid basidiospores. They display a great variation in basidioma morphology, including erect and effused forms and gilled and nongilled forms. Earlier studies have shown these taxa to be related, and the group has been named the russuloid clade. Phylogenetic relationships among russuloid basidiomycetes were investigated using sequence data from the nuclear 5.8S, ITS2 and large-subunit rDNA genes. A dataset including 127 ingroup sequences representing 43 genera and ca 120 species were analyzed by maximum-parsimony and neighbor-joining methods. The sampling of taxa had an emphasis on nongilled taxa and two-thirds of the species possessed corticioid basidiomata. Thirteen major well-supported clades were identified within the russuloid clade. All clades except one include corticioid species. Ten characters from basidioma morphology and cultured mycelium were observed and evaluated. Results suggest that gloeocystidia are a synapomorphy for taxa within the russuloid clade while the amyloidity of spores is inconsistent. The ornamentation of spores and type of nuclear behavior seems to be informative characters at genus level. The agaricoid genera Lactarius and Russula are nested in a clade with corticioid species at the basal position. The new combinations Boidinia aculeata, Gloeodontia subasperispora, Gloeocystidiopsis cryptacantha and Megalocystidium wakullum are proposed.     

Evolutionary relationships of euthyneuran gastropods (Mollusca): a cladistic re-evaluation of morphological characters

Morphological characters of the Euthyneura available from the literature were re-evaluated in terms of terminology and primary homology. A total of 77 characters and 75 taxa were retained in a data matrix. Several assumptions on character weights and types were tested. In the cladistic analyses, it appeared that the data matrix was highly homoplastic, and only robust nodes (those which were little modified by variations in weight and coding of characters) were retained in a concensus tree. The evolutionary histories of all characters and monophylies of higher euthyneuran taxa were discussed. The following interrelationships of the taxa were obtained in a consensus tree: the clade Heterobranchia includes paraphyletic allogastropod taxa which emerge basally, and the clade Euthyneura. The latter includes the clade Pulmonata and at least 10 opisthobranch clades of unresolved relationship (Thecosomata, Gymnosomata, Acochlidioidea, Pyramidelloidea, Runcinoidea, Cephalaspidea, Sacoglossa, Umbraculoidea, Pleurobranchoidea, Nudibranchia). The Pulmonata include basommatophoran paraphyletic taxa and the clade Geophila (Onchidiidae, Soleolifera, Stylommatophora). The position of the Sacoglossa and the monophyly of the Notaspidea are also discussed.  © 2002 The Linnean Society of London, Zoological Journal of the Linnean Society , 2002, 135 , 403–470.