Phylogeny of the cycads based on multiple single-copy nuclear genes: congruence of concatenated parsimony,likelihood and species tree inference methods

Background and aims

Despite a recent new classification, a stable phylogeny for the cycads has been elusive, particularly regarding resolution of Bowenia, Stangeria and Dioon. In this study, five single-copy nuclear genes (SCNGs) are applied to the phylogeny of the order Cycadales. The specific aim is to evaluate several gene tree–species tree reconciliation approaches for developing an accurate phylogeny of the order, to contrast them with concatenated parsimony analysis and to resolve the erstwhile problematic phylogenetic position of these three genera.

Methods

DNA sequences of five SCNGs were obtained for 20 cycad species representing all ten genera of Cycadales. These were analysed with parsimony, maximum likelihood (ML) and three Bayesian methods of gene tree–species tree reconciliation, using Cycas as the outgroup. A calibrated date estimation was developed with Bayesian methods, and biogeographic analysis was also conducted.

Key Results

Concatenated parsimony, ML and three species tree inference methods resolve exactly the same tree topology with high support at most nodes. Dioon and Bowenia are the first and second branches of Cycadales after Cycas, respectively, followed by an encephalartoid clade (Macrozamia–Lepidozamia–Encephalartos), which is sister to a zamioid clade, of which Ceratozamia is the first branch, and in which Stangeria is sister to Microcycas and Zamia.

Conclusions

A single, well-supported phylogenetic hypothesis of the generic relationships of the Cycadales is presented. However, massive extinction events inferred from the fossil record that eliminated broader ancestral distributions within Zamiaceae compromise accurate optimization of ancestral biogeographical areas for that hypothesis. While major lineages of Cycadales are ancient, crown ages of all modern genera are no older than 12 million years, supporting a recent hypothesis of mostly Miocene radiations. This phylogeny can contribute to an accurate infrafamilial classification of Zamiaceae.     

Structure and development of the style base in Abildgaardia, Bulbostylis, and Fimbristylis (Cyperaceae,Cyperoideae, Abildgaardieae)

The Abildgaardieae tribe within the family Cyperaceae comprises six or seven genera, among which Abildgaardia, Bulbostylis and Fimbristylis pose a challenge regarding their morphological delimitation. Molecular phylogenetic analyses including species of Abildgaardieae are rare, but in most of those studies, Abildgaardia and Fimbristylis appear as more closely related to each other than to the Bulbostylis genus. Duration of the style base has been one of the most widely used characters for delimiting these three genera. The style base is a persistent structure in most species of Bulbostylis and deciduous in Abildgaardia and Fimbristylis. The reasons why the style base may persist or fall off have been scarcely discussed. The assumption that abscission layers are present in the style base of all three genera and the fact that tracheids have been observed in the style base of Bulbostylis suggest that this structure might have histological complexity. In view of this, a complete ontogenetic and anatomical study of the gynoecium has been carried out for all these three genera. It turned out that the style base is histologically simple in Abildgaardia, Bulbostylis and Fimbristylis and shows similar structure and development in all three genera. The fact that the style base has a shorter duration in Abildgaardia and Fimbristylis than in Bulbostylis might be related to the lower number of sclerotised cells that make up such structures in the mature fruit of the former two genera. Abscission of the style and style base may be the result of much simpler reasons than the differentiation of an abscission layer, resulting merely from mechanical shear force effects. Differences among genera have been observed in the shape of the style base and the development of the style. The histological simplicity of the style base is consistent with the homoplastic appearance of this structure in genera that are not closely related (e.g. Rhynchospora). Because of this, while the presence of the thickened style base seems to be a synapomorphy in species of Abildgaardieae, its persistence on or detachment from the fruit might have emerged repeatedly during this clade evolution and might not be a suitable character for genera delimitation.     

Historical biogeography and character evolution of Cistaceae (Malvales) based on analysis of plastid rbcL and trnL-trnF sequences

Cistaceae consist of eight genera and about 180 species. Some taxonomic limits and relationships within the family remain unresolved when relying exclusively on morphological data. In the present study, a phylogeny was reconstructed and divergence times were estimated for 47 species representing various groups in Cistaceae and using coding (rbcL) and spacer (trnL-trnF) sequences of plastid DNA. The firm set of morphological synapomorphies that indicates the monophyly of the family is supported by both Bayesian and parsimony analyses. Five major lineages can be distinguished within the Cistaceae: (1) an early-diverging lineage containing Fumana species; (2) the New World Lechea clade; (3) the Helianthemum s.l. clade, containing two sister groups, one of species from the New World (Crocanthemum, Hudsonia) and the other with species from the Old World (Helianthemum s. str.); (4) the Tuberaria clade; and (5) a cohesive complex consisting of Halimium and Cistus species. Evolutionary shifts in 12 key characters of Cistaceae are inferred based on the most plausible phylogenetic hypothesis. Reconstructing the evolution of ovule position supports anatropous ovules as the ancestral condition within the Cistaceae, which is currently found only in Fumana. The Cistus-Halimium assemblage is consistently obtained as a natural clade and further supported by a cytological synapomorphy (chromosome number n=9). Optimisation of ancestral distribution areas and estimates of divergence times reveal an early divergence (10.17-18.51 Ma) of the Mediterranean-European genera, which may be related to subtropical vegetation, as complemented by paleobotanical data. In addition, the occurrence of multiple, independent migration events from the Old World to America between the Middle Miocene (8.44-14.7 Ma; Lechea) and the Upper Miocene (5.15-9.20 Ma; Crocanthemum/Hudsonia), and to the Canary Islands in the Pleistocene is inferred. We argue that the Mediterranean basin has been the main centre of differentiation of Cistaceae.     

Distribution and phylogenetic significance of the 71-kb inversion in the plastid genome in Funariidae (Bryophyta)

BACKGROUND AND AIMS: The recent assembly of the complete sequence of the plastid genome of the model taxon Physcomitrella patens (Funariaceae, Bryophyta) revealed that a 71-kb fragment, encompassing much of the large single copy region, is inverted. This inversion of 57% of the genome is the largest rearrangement detected in the plastid genomes of plants to date. Although initially considered diagnostic of Physcomitrella patens, the inversion was recently shown to characterize the plastid genome of two species from related genera within Funariaceae, but was lacking in another member of Funariidae. The phylogenetic significance of the inversion has remained ambiguous. METHODS: Exemplars of all families included in Funariidae were surveyed. DNA sequences spanning the inversion break ends were amplified, using primers that anneal to genes on either side of the putative end points of the inversion. Primer combinations were designed to yield a product for either the inverted or the non-inverted architecture. KEY RESULTS: The survey reveals that exemplars of eight genera of Funariaceae, the sole species of Disceliaceae and three generic representatives of Encalyptales all share the 71-kb inversion in the large single copy of the plastid genome. By contrast, the plastid genome of Gigaspermaceae (Funariales) is characterized by a gene order congruent with that described for other mosses, liverworts and hornworts, and hence it does not possess this inversion. CONCLUSIONS: The phylogenetic distribution of the inversion in the gene order supports a hypothesis only weakly supported by inferences from sequence data whereby Funariales are paraphyletic, with Funariaceae and Disceliaceae sharing a common ancestor with Encalyptales, and Gigaspermaceae sister to this combined clade. To reflect these relationships, Gigaspermaceae are excluded from Funariales and accommodated in their own order, Gigaspermales order nov., within Funariideae.     

Comparative study of floral development in Onobrychis melanotricha, Hedysarum varium and Alhagi persarum (Leguminosae: Papilionoideae: Hedysareae)

Floral initiation and development of Hedysarum varium, Onobrychis melanotricha and Alhagi persarum was studied using epi-illumination light-microscopy techniques. The studied species belong to the tribe Hedysareae of the inverted repeat loss clade (IRLC clade), which is characterized by missing the large inverted repeat in the chloroplast genome. The main aim of our study was to determine developmental bases for similarities and differences among the three taxa and to verify the position of Alhagi relative to other genera of the IRLC clade. According to our observations, bracteoles are missing in Onobrychis melanotricha, but are present in the other two species. All three species share unidirectional sepal initiation starting with a median abaxial sepal and bidirectional petal initiation. Stamen initiation is unidirectional in all except in the outer stamen whorl of Hedysarum varium, where it is bidirectional. An important ontogenetic feature in O. melanotricha is the existence of five common primordia, which give rise to petal and stamen primordia. Although in H. varium and O. melanotricha common primordia are observed at some stages in floral organ initiations, in Alhagi all organs are initiated separately. Moreover, overlap in time of floral organs initiation occurs in H. varium and O. melanotricha, but not in A. persarum. The carpel initiates concurrently with the petal primordia in all. It might be presumed that Alhagi is primitive in relation to the other studied Hedysareae taxa, due to the presence of bracteoles, the absence of common primordia, and the lack of overlap in time of different organ initiations.     

Molecular phylogenetic evidence supports a new family of octocorals and a new genus of Alcyoniidae (Octocorallia,Alcyonacea)

Molecular phylogenetic evidence indicates that the octocoral family Alcyoniidae is highly polyphyletic, with genera distributed across Octocorallia in more than 10 separate clades. Most alcyoniid taxa belong to the large and poorly resolved Holaxonia–Alcyoniina clade of octocorals, but members of at least four genera of Alcyoniidae fall outside of that group. As a first step towards revision of the family, we describe a new genus, Parasphaerasclera gen. n., and family, Parasphaerascleridae fam. n., of Alcyonacea to accommodate species of Eleutherobia Pütter, 1900 and Alcyonium Linnaeus, 1758 that have digitiform to digitate or lobate growth forms, completely lack sclerites in the polyps, and have radiates or spheroidal sclerites in the colony surface and interior. Parasphaerascleridae fam. n. constitutes a well-supported clade that is phylogenetically distinct from all other octocoral taxa. We also describe a new genus of Alcyoniidae, Sphaerasclera gen. n., for a species of Eleutherobia with a unique capitate growth form. Sphaerasclera gen. n. is a member of the Anthomastus–Corallium clade of octocorals, but is morphologically and genetically distinct from Anthomastus Verrill, 1878 and Paraminabea Williams & Alderslade, 1999, two similar but dimorphic genera of Alcyoniidae that are its sister taxa. In addition, we have re-assigned two species of Eleutherobia that have clavate to capitate growth forms, polyp sclerites arranged to form a collaret and points, and spindles in the colony interior to Alcyonium, a move that is supported by both morphological and molecular phylogenetic evidence.     

Distribution of exudate flavonoids in the genus Plectranthus

Thirty-four species of the genus Plectranthus (including species of the former genera Coleus and Solenostemon, fam. Lamiaceae) were surveyed for exudate flavonoids to see whether the distribution of these compounds would support a recent classification of the genus based on molecular and morphological characters. In this classification two major groups had been identified, the Coleus and Plectranthus clades. Only about 40% of the species, predominantly from the Plectranthus clade, were found to produce exudate flavonoids, which were mainly flavones. Flavanones were restricted to five species of the Plectranthus clade, whereas flavonols were only found in two species of the Coleus clade, Plectranthus montanus Benth. (synonyms Plectranthus marrubioides Hochst. ex Benth. and Plectranthus cylindraceus Hochst. ex Benth.) and Plectranthus pseudomarrubioides R.H.Willemse. Four of these flavonols were isolated from P. montanus and identified by NMR spectroscopy as the 3,7-dimethyl ether and 3,7,4′-trimethyl ether of quercetin and the 3,6,7-trimethyl ether and 3,6,7,4′-tetramethyl ether of quercetagetin. The remaining flavonols and flavones were identified by HPLC–UV and LC–MS of crude extracts on the basis of their UV and mass spectra, retention times and comparison with standards. Most flavonols were 3-methyl ethers and many of the flavones and flavonols were oxygenated at the 6-position. The most common flavones, occurring in both clades, were cirsimaritin and salvigenin, which are methoxylated at the 6- and 7-positions. 6-Hydroxylated flavones such as scutellarein and ladanein were restricted to species of the Plectranthus clade.     

Typical cyperoid reproductive structures in Lipocarpha humboldtiana and Ascolepis brasiliensis (Cypereae – Cyperoideae – Cyperaceae): New evidence from a development perspective

Ascolepis and Lipocarpha, Cyperaceae, have highly reduced reproductive structures and hypogynous scales that are controversially appreciated. Because of this, flowers and spikelets and, thus, inflorescences have been interpreted in different ways, which, in turn, has led to placing the two genera in different tribes. Some authors interpret spikelets in Ascolepis and Lipocarpha as many-flowered and the so-called hypogynous scales as homologous to the lateral scales of Hypolytrum, or consider these scales comparable to a Scirpus bristle. However, many other authors consider spikelets in Lipocarpha and Ascolepis to be a result of a reductional process from a many-flowered cyperoid spikelet to a single-flowered spikelet, where the adaxial and abaxial hypogynous scales may be seen as the respective prophyll and glume of the reduced spikelets. The latest molecular phylogenies of Cyperaceae show both genera nested in the Cyperus clade, forming, in turn, a clade together with the rest of the Cypereae genera having single-flowered spikelets and hypogynous scales. Alternatively, based on this, the scales of uncertain homology that accompany the Ascolepis and Lipocarpha flower might be seen as special reproductive formations, representing a synapomorphy of such clade, instead of relicts of an ancestor with many-flowered spikelets. In view of this, freshly collected inflorescences of Lipocarpha humboldtiana Nees and Ascolepis brasiliensis (Kunth) Benth. ex C. B. Clarke were studied using light and scanning electron microscopy, with the aim of elucidating the nature of the controversially interpreted reproductive structures of these species from a development perspective. Results show that the “hypogynous scales” simply represent vestigial structures derived from the reduction of typical cyperoid spikelets, rather than a perianth part or specialized formations emerging as evolutionary novelties. Two scales are typically generated in both species, one being abaxial and the other adaxial, homologous to a glume and a prophyll, respectively, which contrasts with the eprophyllate condition so far attributed to Ascolepis. In both cases, the inflorescence is a spike of reduced spikelets, and the floral development in L. humboldtiana and in A. brasiliensis follows the general ontogenetic pattern observed in Cyperoideae. These characteristics support the inclusion of both genera in the Cypereae tribe.     

Zygomorphy evolved from disymmetry in Fumarioideae (Papaveraceae,Ranunculales): new evidence from an expanded molecular phylogenetic framework

Background and Aims Fumarioideae (20 genera, 593 species) is a clade of Papaveraceae (Ranunculales) characterized by flowers that are either disymmetric (i.e. two perpendicular planes of bilateral symmetry) or zygomorphic (i.e. one plane of bilateral symmetry). In contrast, the other subfamily of Papaveraceae, Papaveroideae (23 genera, 230 species), has actinomorphic flowers (i.e. more than two planes of symmetry). Understanding of the evolution of floral symmetry in this clade has so far been limited by the lack of a reliable phylogenetic framework. Pteridophyllum (one species) shares similarities with Fumarioideae but has actinomorphic flowers, and the relationships among Pteridophyllum, Papaveroideae and Fumarioideae have remained unclear. This study reassesses the evolution of floral symmetry in Papaveraceae based on new molecular phylogenetic analyses of the family.Methods Maximum likelihood, Bayesian and maximum parsimony phylogenetic analyses of Papaveraceae were conducted using six plastid markers and one nuclear marker, sampling Pteridophyllum, 18 (90 %) genera and 73 species of Fumarioideae, 11 (48 %) genera and 11 species of Papaveroideae, and a wide selection of outgroup taxa. Floral characters recorded from the literature were then optimized onto phylogenetic trees to reconstruct ancestral states using parsimony, maximum likelihood and reversible-jump Bayesian approaches.Key Results Pteridophyllum is not nested in Fumarioideae. Fumarioideae are monophyletic and Hypecoum (18 species) is the sister group of the remaining genera. Relationships within the core Fumarioideae are well resolved and supported. Dactylicapnos and all zygomorphic genera form a well-supported clade nested among disymmetric taxa.Conclusions Disymmetry of the corolla is a synapomorphy of Fumarioideae and is strongly correlated with changes in the androecium and differentiation of middle and inner tepal shape (basal spurs on middle tepals). Zygomorphy subsequently evolved from disymmetry either once (with a reversal in Dactylicapnos) or twice (Capnoides, other zygomorphic Fumarioideae) and appears to be correlated with the loss of one nectar spur.     

Phylogenetic relationships of mullets (Mugilidae) in China Seas based on partial sequences of two mitochondrial genes

Phylogenetic analyses of Mugilidae species from the China coast were carried out based on 16S and 12S rRNA mitochondrial gene sequences by maximum parsimony, maximum likelihood, Bayesian inference and neighbor joining analysis in the present study. The results suggested that Mugil cephalus is the most genetically divergent species among the Mugilidae. The four Liza species clustered together and formed a monophyletic group. The genera Osteomugil showed closer affiliation with Valamugil than with Ellochelon; these three genera then grouped together to form a monophyletic clade presenting as the sister group to Liza. Analyses of phylogenetic and genetic distance indicated that Southern and Northern lineages of Liza haematocheila may be two different species; likewise, strong genetic divergence existed between Southern and Northern M. cephalus lineages. In addition, our results supported the Southern origin of Chinese Mugilids, which is contrary to the hypothesis based on morphological characters.     

The evolution of peafowl and other taxa with ocelli (eyespots): a phylogenomic approach

The most striking feature of peafowl (Pavo) is the males'' elaborate train, which exhibits ocelli (ornamental eyespots) that are under sexual selection. Two additional genera within the Phasianidae (Polyplectron and Argusianus) exhibit ocelli, but the appearance and location of these ornamental eyespots exhibit substantial variation among these genera, raising the question of whether ocelli are homologous. Within Polyplectron, ocelli are ancestral, suggesting ocelli may have evolved even earlier, prior to the divergence among genera. However, it remains unclear whether Pavo, Polyplectron and Argusianus form a monophyletic clade in which ocelli evolved once. We estimated the phylogeny of the ocellated species using sequences from 1966 ultraconserved elements (UCEs) and three mitochondrial regions. The three ocellated genera did form a strongly supported clade, but each ocellated genus was sister to at least one genus without ocelli. Indeed, Polyplectron and Galloperdix, a genus not previously suggested to be related to any ocellated taxon, were sister genera. The close relationship between taxa with and without ocelli suggests multiple gains or losses. Independent gains, possibly reflecting a pre-existing bias for eye-like structures among females and/or the existence of a simple mutational pathway for the origin of ocelli, appears to be the most likely explanation.     

The phylogenetic placement of hypocrealean insect pathogens in the genus Polycephalomyces: An application of One Fungus One Name

Understanding the systematics and evolution of clavicipitoid fungi has been greatly aided by the application of molecular phylogenetics. They are now classified in three families, largely driven by reevaluation of the morphologically and ecologically diverse genus Cordyceps. Although reevaluation of morphological features of both sexual and asexual states were often found to reflect the structure of phylogenies based on molecular data, many species remain of uncertain placement due to a lack of reliable data or conflicting morphological characters. A rigid, darkly pigmented stipe and the production of a Hirsutella-like anamorph in culture were taken as evidence for the transfer of the species Cordyceps cuboidea, Cordyceps prolifica, and Cordyceps ryogamiensis to the genus Ophiocordyceps. Data from ribosomal DNA supported these species as a single group, but were unable to infer deeper relationships in Hypocreales. Here, molecular data for ribosomal and protein coding DNA from specimens of Ophiocordyceps cuboidea, Ophiocordyceps ryogamiensis, Ophiocordyceps paracuboidea, Ophiocordyceps prolifica, Cordyceps ramosopulvinata, Cordyceps nipponica, and isolates of Polycephalomyces were combined with a broadly sampled dataset of Hypocreales. Phylogenetic analyses of these data revealed that these species represent a clade distinct from the other clavicipitoid genera. Applying the recently adopted single system of nomenclature, new taxonomic combinations are proposed for these species in the genus Polycephalomyces, which has been historically reserved for asexual or anamorphic taxa.     

Morphology agrees with molecular data: phylogenetic affinities of Euptychiina butterflies (Nymphalidae: Satyrinae)

Euptychiina is the most species‐rich subtribe of Neotropical Satyrinae, with over 450 known species in 47 genera (14 monotypic). Here, we use morphological characters to examine the phylogenetic relationships within Euptychiina. Taxonomic sampling included 105 species representing the majority of the genera, as well as five outgroups. A total of 103 characters were obtained: 45 from wing pattern, 48 from genitalia and 10 from wing venation. The data matrix was analysed using maximum parsimony under both equal and extended implied weights. Euptychiina was recovered as monophyletic with ten monophyletic genera, contrasting previous DNA sequence‐based phylogenies that did not recover the monophyly of the group. In agreement with sequence‐based hypotheses, however, three main clades were recognized: the ‘Megisto clade’ with six monophyletic and three polyphyletic genera, the ‘Taygetis clade’ with nine genera of which three were monophyletic, and the ‘Pareuptyhia clade’ with four monophyletic and two polyphyletic genera. This is the first morphology‐based phylogenetic hypothesis for Euptychiina and the results will be used to complement molecular data in a combined analysis and to provide critical synapomorphies for clades and genera in this taxonomically confused group.     

A review of the morphology and relationships of the Oligocene spikefish generaAcanthopleurus Agassiz 1844 andCryptobalistes Tyler 1968 (Tetraodontiformes: Triacanthidae)

A fish from the early Oligocene (Rupelian) of Canton Glarus, Switzerland,Cryptobalistes brevis (Rath 1859), until now placed incertae sedis among triacanthoid tetraodontiforms, is shown to be a triacanthid. It is redescribed and compared with the only other known fossil triacanthids, these being the two species ofAcanthopleurus, also from Canton Glarus, and with the seven Recent species of four genera. All of these triacanthids share five derived features. The four Recent genera are in a clade defined by five synapomorphies, andCryptobalistes andAcanthopleurus form an unresolved trichotomy with that clade. Reconstructions of the three fossil species are provided.     

Analysis of DNA sequences of six chloroplast and nuclear genes suggests incongruence, introgression, and incomplete lineage sorting in the evolution of Lespedeza (Fabaceae)

The genus Lespedeza (Fabaceae) consists of 40 species disjunctively distributed in East Asia and eastern North America. Phylogenetic relationships of all Lespedeza species and closely related genera were reconstructed using maximum parsimony, maximum likelihood, and Bayesian analyses of sequence data from five chloroplast (rpl16, rpl32-trnL, rps16-trnQ, trnL-F, and trnK/matK) and one nuclear (ITS) DNA regions. All analyses yielded consistent relationships among major lineages. Our results suggested that Campylotropis, Kummerowia, and Lespedeza are monophyletic, respectively. Lespedeza is resolved as sister to Kummerowia and these two together are further sister to Campylotropis. Neither of the two subgenera, subgen. Lespedeza and subgen. Macrolespedeza, in Lespedeza based on morphological characters, is recovered as monophyletic. Within Lespedeza, the North American clade is retrieved as sister to the Asian clade. The nuclear and chloroplast markers showed incongruent phylogenetic signals at shallow-level phylogeny, which may point to either introgression or incomplete lineage sorting in Lespedeza. The divergence times within Lespedeza and among related genera were estimated using Bayesian approach with BEAST. It is assumed that following the divergence between Kummerowia and Lespedeza in Asia in the late Miocene, the ancestor of Lespedeza diverged into the North American and the Asian lineages. The North American ancestor quickly migrated to North America through the Bering land bridge in the late Miocene. The North American and Asian lineages started to diversify almost simultaneously in the late Miocene but resulted in biased numbers of species in two continents.     

Are unusual plasmodesmata in the embryo-suspensor restricted to species from the genus Sedum among Crassulaceae?

The Crassulaceae family comprises mainly herbaceous leaf succulents, some of which have an ornamental value. During embryogenesis, they produce a suspensor with a giant polyploid basal cell. It has recently been shown that in Sedum acre and S. hispanicum this cell has compound plasmodesmata with an unusual dome of electron-dense material associated on the cell's side. These compound plasmodesmata differ from the typical ones occurring in other angiosperms. In this study, the hypothesis was tested that the unusual plasmodesmata in the embryo-suspensor are a feature not only restricted to species from the genus Sedum, but are also found in other Crassulaceae genera. Suspensors of example species from the genera Sempervivum and Jovibarba, which have vegetative morphologies quite different from Sedum and which are placed in the traditional classification into another subfamily, were first examined using an electron microscope. It was found that the unusual compound plasmodesmata in the suspensor are not only restricted to species from the genus Sedum but are also found in species from other Crassulaceae genera (Sempervivum arachnoideum and Jovibarba sobolifera). It should be noted that some ultrastructural features of compound plasmodesmata in the analyzed genera (e.g. the character of the wall with plasmodesmata, plasmodesmata diameter or occurrence of the electron-dense material) are different from the suspensor plasmodesmata recorded in species from the Sedum genus. We found that in Sempervivum arachnoideum the size of the plasmodesmata diameter varies according to the micropylar-chalazal axis of the embryo. This is the first report of variation in the diameter of the plasmodesmata within the embryo of angiosperms. Further study will be needed to show whether compound plasmodesmata occur in other Crassulaceae clades, whether they are a stable feature at the genus level in this family, and also whether they have evolved several times or only once in Crassulaceae.     

Phylogenetic status of Xylaria subgenus Pseudoxylaria among taxa of the subfamily Xylarioideae (Xylariaceae) and phylogeny of the taxa involved in the subfamily

To infer the phylogenetic relationships of Xylaria species associated with termite nests within the genus Xylaria and among genera of the subfamily Xylarioideae, β-tubulin, RPB2, and α-actin sequences of 131 cultures of 114 species from Xylaria and 11 other genera of the subfamily were analyzed. These 11 genera included Astrocystis, Amphirosellinia, Discoxylaria, Entoleuca, Euepixylon, Kretzschmaria, Nemania, Podosordaria, Poronia, Rosellinia, and Stilbohypoxylon. We showed that Xylaria species were distributed among three major clades, TE, HY, and PO, with clade TE—an equivalent of the subgenus Pseudoxylaria—encompassing exclusively those species associated with termite nests and the other two clades containing those associated with substrates other than termite nests. Xylaria appears to be a paraphyletic genus, with most of the 11 genera submerged within it. Podosordaria and Poronia, which formed a distinct clade, apparently diverged from Xylaria and the other genera early. Species of Entoleuca, Euepixylon, Nemania, and Rosellinia constituted clade NR, a major clade sister to clade PO, while those of Kretzschmaria were inserted within clade HY and those of Astrocystis, Amphirosellinia, Discoxylaria, and Stilbohypoxylon were within clade PO.     

Phylogenetic relationships of the algae scraping cyprinid genus Capoeta (Teleostei: Cyprinidae)

We reconstructed the matrilineal phylogeny of Asian algae-eating fishes of the genus Capoeta based on complete mitochondrial gene for cytochrome b sequences obtained from 20 species sampled from the majority of the range and 44 species of closely related barbs of the genera Barbus s. str. and Luciobarbus. The results of this study show that Capoeta forms a strongly supported monophyletic subclade nested within the Luciobarbus clade, suggesting that specialized scraping morphology appeared once in the evolutionary history of the genus. We detected three main groups of Capoeta: the Mesopotamian group, which includes three species from the Tigris-Euphrates system and adjacent water bodies, the Anatolian-Iranian group, which has the most diversified structure and encompasses many species distributed throughout Anatolian and Iranian inland waters, and the Aralo-Caspian group, which consists of species distributed in basins of the Caspian and Aral Seas, including many dead-end rivers in Central Asia and Northern Iran. The most probable origination pathway of the genus Capoeta is hypothesized to occur as a result of allopolyploidization. The origin of Capoeta was found around the Langhian-Serravallian boundary according to our molecular clock. The diversification within the genus occurred along Middle Miocene-Late Pliocene periods.