Phylogenetic relationships in theSideritis leucantha group (Lamiaceae)

Six closely related taxa of the sect.Eusideritis of the genusSideritis (S. leucantha, S. pusilla, S. flavovirens, S. granatensis, S. biflora andS. osteoxylla) are analysed to elucidate their phylogenetic relationships and position within the sect.Eusideritis. Meiotic behaviour, karyotype features, size and fertility of pollen grains, DNA amounts and seed protein profiles are reviewed. A polyploid origin of the group (from x = 7) and the further diversification through dysploidy and chromosome repatterning is postulated.S. osteoxylla is apparently of hybrid origin.     

Across-population variation in sex ratio in invasive Japanese Potamopyrgus antipodarum (Caenogastropoda: Rissooidea: Hydrobiidae)

Potamopyrgus antipodarum, a well-known invasive species, has both sexual and asexual forms in its native area, and is generally asexual in exotic areas. Potamopyrgus antipodarum was sampled from ten locations in central and western Japan, and the sex distribution was analyzed. Males were found in two of the ten localities; the percentages of males in these localities were 7.2 and 7.3 %, which is within the range of that observed in asexual populations in native and introduced areas. A flow cytometry analysis showed that populations with a low percentage of males (Kanro) and populations consisting only of females (Banyu Park, Hadano and Yugawara) and perhaps the population reported as having a high male percentage in a previous study (Chiba; 29.8 %) were triploid. Males from Chiba and Kanro produced sperm. Most of the females from Chiba stored sperm in their seminal receptacle, showing that they had copulated, but no females from Kanro stored sperm. Fertilization by males, normal development of fertilized eggs, and the fecundity of juveniles should be evaluated in further studies to demonstrate the sexual reproduction of P. antipodarum in Japan. The risk of introduction of sexual P. antipodarum individuals is further discussed in the article.     

Radiation of crenobiontic gastropods on an ancient continental island: the Hemistomia-clade in New Caledonia (Gastropoda: Hydrobiidae)

A vast radiation of hydrobiid spring snails endemic to New Caledonia, a continental island in the Southwest Pacific known for its unique flora and fauna, is described. This radiation comprises a total of 54 named species of which 50 are new. The majority of the species belong to the most basal genus, Hemistomia, which happens to be the first one described from New Caledonia. The remaining species are attributed to four genera, Kanakyella, Pidaconomus, Caledoconcha, and Leiorhagium, which are all introduced in this paper. The radiation as a whole is characterized by the formation of the digestive gland, the stomach with an additional, ciliated proximal chamber, and the subdivision of the pallial oviduct. Whether or not a denticle situated behind the outer lip is a synapomorphy of the whole group cannot be stated with certainty. The genera are distinguished mainly by features of the genital system. For the cladistic analysis, which resulted in 419 equally parsimonious trees, only five characters could be used, and even those were not free of homoplasy. The genera Hemistomia and Pidaconomus are paraphyletic according to this analysis. In contrast to the widely accepted principles of phylogenetic systematics we retain these paraphyletic genera, because otherwise the diversification, i.e. the evolution, which has taken place within the clade could not be expressed in the classification. The majority of the species occur in very restricted areas. Twenty-six (48%) species were found in a single locality and only six species (11%) in ten or more places. The hydrobiid diversity of west coast drainages is much higher than that of river systems draining to the east. This is, at least partly, explained by the differing precipitation regimes and geological conditions of the regions considered. The west coast receives much less rainfall so that in continuous periods of drought the area of a species would be fragmented by drying up of springs and consequently gene flow between the remaining populations reduced, enhancing speciation. In addition, the west is geologically more heterogenous. Unfavourable, insular ultramafic mountains represent barriers for the dispersal along the west coast. Many of the taxa are highly threatened to become extinct in the closer future as a consequence of human activities, such as deforestation, agriculture, surface mining, or uncontrolled fires. The conservation of the unique New Caledonian radiation of crenobiontic gastropods requires a transformation of land management practices on privately-owned sites, and a more global reappraisal of the impact of fire and deforestation on water resources. This revised version was published online in July 2006 with corrections to the Cover Date.     

Salenthydrobia gen. nov. (Rissooidea: Hydrobiidae): a potential relict of the Messinian salinity crisis

The Messinian salinity crisis (MSC) occurred synchronously throughout the Mediterranean basin about 5.96 ± 0.02 Mya and represents one of the most dramatic oceanic changes since the early Miocene. It is thought that the concomitant environmental changes brought about isolation of faunas and the development of endemism. As part of the search for possible speciation events triggered by the MSC, the author studied 38 populations of hydrobiine snails from the Mediterranean and Black Sea, including three populations from the Salentina Peninsula, Italy. Partial sequences (COI, 16S) and anatomical data were used to test the taxonomic and phylogenetic status of the peninsular populations. A maximum likelihood analysis of 11 hydrobiine taxa revealed five clades and lineages, four of which corresponded to previously recognized genera: Adriohydrobia , Hydrobia , Peringia , Ventrosia . The fifth clade was formed by haplotypes of the peninsular populations, which are characterized by distinct male and female reproductive systems. Based on molecular and anatomical data, these populations are considered to represent a new species, Salenthydrobia ferrerii , belonging to a new genus, Salenthydrobia . Ecological and biogeographical data for S. ferrerii strongly support a correlation between its origin and the MSC. Based on an island age of 5.33 Myr and a population divergence of 0.0973 ± 0.0114, the COI molecular clock rate for the Salenthydrobia and Peringia clades would be 1.83 ± 0.21% population divergence per Myr. The genetic diversity of S. ferrerii , its phylogenetic relationships, and the validity of the proposed local molecular clock rate are discussed.     

Phylogenetic relationships of the enigmatic species Serratula chinensis and Serratula forrestii (Asteraceae - Cardueae)

The phylogenetic relationships of the Chinese species Serratula forrestii and S. chinensis within the subtribe Centaureinae (Asteraceae – Cardueae) were investigated based on nuclear ribosomal DNA external and internal transcribed spacer sequences. Results indicated that Serratula s. l. is clearly polyphyletic, none of the two species showing close affinities to either Serratula s. str. or Klasea, a genus traditionally included in Serratula. Serratula forrestii has a basal position within the subtribe and has retained most plesiomorphic character states. Serratula chinensis is related to the genera of the Rhaponticum group. Its chromosome number was determined as 2n = 26, and the relationship between this species and the Rhapon-ticum group is discussed from a morphological and karyological point of view.     

Phylogenetic relationships and evolution of pulmonate gastropods (Mollusca): new insights from increased taxon sampling

Phylogenetic relationships among higher clades of pulmonate gastropods are reconstructed based on a data set including one nuclear marker (complete ribosomal 18S) and two mitochondrial markers (partial ribosomal 16S and Cytochrome oxidase I) for a total of 96 species. Sequences for 66 of these species are new to science, with a special emphasis on sampling the Ellobiidae, Onchidiidae, and Veronicellidae. Important results include the monophyly of Systellommatophora (Onchidiidae and Veronicellidae) as well as the monophyly of Ellobiidae (including Trimusculus, Otina, and Smeagol). Relationships within Ellobiidae, Onchidiidae, and Veronicellidae are evaluated here for the first time using molecular data. Present results are compared with those from the recent literature, and the current knowledge of phylogenetic relationships among pulmonate gastropods is reviewed: despite many efforts, deep nodes are still uncertain. Identification uncertainties about early fossils of pulmonates are reviewed. Impacts of those phylogenetic and fossil record uncertainties on our understanding of the macro-evolutionary history of pulmonates, especially transitions between aquatic and terrestrial habitats, are discussed.     

Relationships and origin of endemic Lake Baikal gastropods (Caenogastropoda: Rissooidea) based on mitochondrial DNA sequences

The phylogenetic relationships and the origin of two groups of rissooid freshwater snails endemic to Lake Baikal were investigated using partial mitochondrial COI, 12S rDNA, and 16S rDNA sequences. The Baikalian Benedictiinae proved to be closely related to the Lithoglyphinae. According to a molecular clock estimate the two groups diverged in the Paleogene. The Benedictiinae might have evolved autochthonously in precursors of Lake Baikal. The Baikalian Baicaliidae are probably most closely related to the Amnicolidae and the Bithyniidae. These groups diverged at the latest during the Cretaceous. Thus the origin of the Baicaliidae predates the origin of the Baikal rift zone. The Baicaliidae evolved probably in other Central Asian freshwater reservoirs. However, the radiation of the extant Baicaliidae only started in the Neogene and might have occurred autochthonously in Lake Baikal. The conchological similarity of the Baicaliidae and the Pyrgulidae is due to convergence. The Pyrgulidae diverged from the common stem lineage of the other hydrobiid families at the latest in the Jurassic. The Bithyniidae is derived from hydrobiids and is related to the Amnicolidae.     

Phylogenetic relationships of the enigmatic ornate shiner,Cyprinella ornata,a species endemic to Mexico (Teleostei: Cyprinidae)

The systematics and taxonomy of North Americancyprinid fishes has historically been said tobe in a chaotic state of affairs. Much of theconfusion as to relationships of species restsin the lack of explicit phylogenetic hypothesesof species and reliance upon degree ofdistinctiveness of taxa or their overallsimilarity for generic placement. Some specieshave had more turbulent or variable taxonomichistories than others. The ornate shiner, Cyprinella ornata, is one of those species,having been placed in the genera Notropis,Codoma, and Cyprinella within the last20 years and found in current texts in any ofthese three genera. Most of the confusionregarding placement of this species has beenrelated to lack of explicit phylogenetichypotheses to formulate its classification, butto a certain degree some researchers haveignored phylogenetic studies and preferred torely upon its morphological distinctiveness orreproductive behavioral traits of questionablehomology to place it in a monotypic genus andalign it with the genera Pimephales andOpsopoeodus.I present a phylogenetic analysis based oncomplete Cytochrome b sequences fromornate shiners, other species of Cyprinella, purported relatives, and severalother species of the Shiner Clade to determinethe phylogenetic affinities of this enigmaticspecies. Molecular analysis reveals the ornateshiner to be more closely related to species ofCyprinella than to a Pimephalesplus Opsopoeodus clade as previouslydiscussed in one morphological analysis, or asargued by Page and Johnston (1990), Johnstonand Page (1992) and Page and Ceas (1989) basedon observations of spawning behaviors andhypotheses of homology between crevice-spawningand egg-clumping behaviors. This molecularanalysis is more consistent with earliermorphological phylogenetic hypotheses of Mayden(1989) wherein these two clades are notconsidered to be closely related and the ornateshiner is a member of the genus Cyprinella.     

Phylogenetic relationships of the enigmatic fern families Hymenophyllopsidaceae and Lophosoriaceae: Evidence fromrbcL nucleotide sequences

Nucleotide sequences fromrbcL were used to infer relationships of Lophosoriaceae and Hymenophyllopsidaceae. The phylogenetic positions of these two monotypic fern families have been debated, and neither group had been included in recent molecular systematic studies of ferns. Maximum parsimony analysis of our data supported a sister relationship betweenLophosoria andDicksonia, and also betweenHymenophyllopsis andCyathea. Thus, both newly-examined families appear to be part of a previously characterized and well-supported clade of tree ferns. The inferred relationships ofLophosoria are consistent with most (but not all) recent treatments. However,Hymenophyllopsis includes only small delicate plants superficially similar to filmy ferns (Hymenophyllaceae), very different from the large arborescent taxa. Nevertheless, some synapomorphic characteristics are shared with the tree fern clade. Further studies on gametophytes ofHymenophyllopsis are needed to test these hypotheses of relationship.     

Phylogenetic relationships of fantails (Aves: Rhipiduridae)

We explore the phylogenetic relationships of fantails (Aves: Rhipiduridae) using molecular characters derived from two nuclear introns and two mitochondrial genes. Our results indicate that Rhipidura hypoxantha is not a true fantail, but rather a member of the Stenostiridae clade that is morphologically and behaviourally convergent with fantails. Within the true Rhipiduridae, we identified six distinct clades; however, phylogenetic relationships among these groups were unresolved. The only well-supported sister relationship was between members of the grey and the rufous fantail complexes. Clades recovered through our model-based phylogenetic analyses generally correspond to previously proposed fantail complexes based on morphological characters. The phylogenetic position of R. atra and R. diluta remain unclear, as sister relationships varied between analyses for the prior whereas the latter was placed as sister to the New Guinea thicket fantails, R. leucothorax and R. threnothorax ; yet significant node support was not recovered for either taxa. Biogeographically, fantails appear to have radiated rapidly and the six clades are not geographically restricted, but instead span South-east Asia, New Guinea, Australia and Pacific Islands.     

Phylogenetic relationships of the Temnocephaloidea (Platyhelminthes)

Temnocephala novaezealandiae (family Temnocephalidae) and Troglocaridicola mrazeki and Scutariella georgica (family Scutariellidae) were studied by electron microscopy in an attempt to reveal characters that would indicate their phylogenetic relationship to other members of the Platyhelminthes. Ultrastructural features of the epidermis in these temnocephaloideans are like those of the neoophoran turbellarians. The epidermis is syncytial, is honeycombed by a multitude of gland necks whose secretions produce an epidermal surface film, and is underlaid by a thick basement membrane. Some cells in the parenchyma are compartmentalized by intrusive cell processes from neighboring parenchymal cells in a fashion similar to parenchymal structure in the Monogenea and Digenea. The spermatozoa have a pair of free 9+1 flagella and contain aligned dense bodies. The Temnocephaloidea is evidently derived from an early rhabdocoel-turbellarian-like ancestor.     

Phylogenetic relationships among calyptraeid gastropods and their implications for the biogeography of marine speciation

Although calyptraeid gastropods are not well understood taxonomically, in part because their simple plastic shells are the primary taxonomic character, they provide an ideal system to examine questions about evolution in the marine environment. I conducted a phylogenetic analysis of calyptraeid gastropods using DNA sequence data from mitochondrial cytochrome oxidase I (COI) and 16S genes and the nuclear 28S gene. The resultant phylogeny was used to examine the biogeographic patterns of speciation in the Calyptraeidae. Parsimony and Bayesian analyses of the combined data sets for 94 calyptraeid operational taxonomic units and 24 outgroups produced well-resolved phylogenies. Both approaches resulted in identical sister-species relationships, and the few differences in deeper topology did not affect biogeographic inferences. The geographic distribution of the species included here demonstrate numerous dispersal events both between the Pacific and Atlantic oceans and across the equator. When parsimony is used to reconstruct the movement from the Pacific to the Atlantic oceans on the phylogeny, there are 12 transitions between oceans, primarily from the Pacific to the Atlantic. When the latitude is coded as north versus south of the equator, the most-parsimonious reconstruction gives the origin of calyptraeids in the north followed by 15 dispersal events to regions south of the equator and no returns to the north. Many clades of the most closely related species are either sympatric or occur along a single coastline. Closely related species can, however, occur in such divergent regions as Southern California and South Africa. There is little evidence for sister-species pairs or larger clades having been split by the Isthmus of Panama or the Benguela upwelling, but the East Pacific Barrier appears to separate the most basal taxa from the rest of the family.     

Phylogenetic relationships of Rhododendroideae (Ericaceae)

The Rhododendroideae are usually recognized as a subfamily within Ericaceae. This group has been considered primitive (i.e., occupying the ancestral or basal position relative to all other Ericaceae) due to the occurrence of separate petals in several taxa, deciduous corollas, and septicidally dehiscent capsules. Previous molecular studies using rbcL and nr18s sequences have indicated that Rhododendroideae may be paraphyletic and cladistically derived (i.e., the relative position in the geneology of Ericaceae is not basal). The matK sequences of 42 taxa from traditional Rhododendroideae and potentially related clades were obtained via standard gene amplication and double-stranded dideoxy sequencing. Phylogenetic analyses of these sequences using Actinidia chinensis as the outgroup indicate that the Rhododendroideae are paraphyletic. Trees obtained in the analyses indicate an expanded rhododendroid clade that includes four major subclades - empetroid, rhodo, ericoid, and phyllodocoid. The ericoid clade is sister to the phyllodocoid clade and the empetroid clade is sister to the rhodo clade. Relationships within the clades are generally well resolved except within the rhodo clade where matK data indicate that Rhododendron is probably paraphyletic. Daboecia and Calluna are included within the ericoid clade; Erica is paraphyletic. Cassiope lies outside the rhododendroid clade. The relationships indicated by the matK data suggest that sympetalous flowers are likely plesiomorphic within rhododendroids.     

Genetic differentiation of aquatic snails (Gastropoda: Hydrobiidae) from artesian springs in arid Australia

Electrophoretic surveys of 10 species of hydrobiid snails in two indigenous genera (Fonscochlea and Trochidrobia) living in arid-zone artesian ‘mound’ springs are reported. The study is based on 96 populations of hydrobiid snails living in 32 different springs representing 18 spring groups in the Lake Eyre Supergroup, northern South Australia. The species-level taxonomy of these snails, previously based on morphological differences alone, was tested and modified. The snails were examined within five clear-cut morphological groups: the two largest, fully aquatic species (Fonscochlea accepta and F. aquatica) were treated independently, as was the amphibious F. Zfidleri The morphologically similar three smaller aquatic species were investigated as a group. Within this group one new species is described and, on the basis of the genetic evidence, two others (F. variabilis and F. conica) are considered conspecific. The four species of Trochidrobia are investigated together and T. punicea separately in more detail. Sympatry between Trochidrobia smithi and T. punicea is recorded for the first time. The springs are arranged in an essentially linear pattern and genetic differentiation largely follows an isolation by distance model, although there is a significant genetic discontinuity between two nearby spring groups, Beresford/Warburton Springs and Strangways Spring, which is presumably the result of differential historical continuity of spring habitat. The size of the spring influences the degree of genetic difference between springs within spring groups, with small springs attaining greater levels of differentiation than large springs. The findings suggest diat if genetic diversity is to be conserved, current management strategies protecting only single springs within a group are inadequate. Despite the considerable number of indigenous species found in these springs, currendy all remain on pastoral leases and some are threatened by the continuing expansion of water extraction from the Great Artesian Basin.     

Phylogenetic relationships of galeaspids (Agnatha)

We present the first parsimony analysis of the agnathan subclass Galeaspida based on the analysis of 53 morphological characters. Three most parsimonious cladograms (126 steps in length; CI = 0.508; RI = 0.801) were discovered. An amended classification of the Galeaspida is proposed corresponding to the present analysis. Our results suggest that hanyangaspids, xiushuiaspids and day on-gaspids from the Llandovery-Wenlock of Silurian are basal galeaspids. Within the remaining galeaspids, three major monophyletic groups (the Eugaleaspidiformes, the Polybranchiaspidiformes and the Huananaspidiformes) are well supported. It is shown that the dorsal fenestrae of the headshield evolved twice within the Galeaspida, one in the polybranchiaspidiform lineage, and the other in the huananaspidiform lineage (nested within the Huananaspidae). The chronological distribution of galeaspids highlights two radiations of the group, one for basal galeaspids and eugaleaspids in the Telychian (Llandovery) of Silurian, and the other for polybranchiaspidiforms and huananaspidiforms in the Lochkovian of Early Devonian. Selected from Vertebrata PalAsiatica, 2006, 44 (1): 1–27     

Phylogenetic relationships of galeaspids (Agnatha)

We present the first parsimony analysis of the agnathan subclass Galeaspida based on the analysis of 53 morphological characters.Three most parsimonious cladograms (126 steps in length;CI=0.508;RI=0.801)were discovered.An amended classification of the Galeaspida is proposed corresponding to the present analysis.Our results suggest that hanyangaspids,xiushuiaspids and dayongaspids from the Llandovery-Wenlock of Silurian are basal galeaspids.Within the remaining galeaspids,three major monophyletic groups (the Eugaleaspidiformes,the Polybranchiaspidiformes and the Huananaspidiformes)are well supported.It is shown that the dorsal fenestrae of the headshield evolved twice within the Galeaspida,one in the polybranchiaspidiform lineage,and the other in the huananaspidiform lineage (nested within the Huananaspidae).The chronological distribution of galeaspids highlights two radiations of the group,one for basal galeaspids and eugaleaspids in the Telychian (Llandovery)of Silurian,and the other for polybranchiaspidiforms and huananaspidiforms in the Lochkovian of Early Devonian.     

Phylogenetic relationships of the Australian lomatiines (Diptera: Bombyliidae)

Cladistic analysis is used to isolate the monophyletic group of genera that comprise the Australian Lomatiinae and to investigate the relationships between the Australian genera. Cladograms of genera in the Australian Tomophthalmae and Lomatiinae are presented. Myonema Roberts and Neosardus Roberts are placed in the Cylleniinae, Antonia Loew remains in the Antoniinae and Petrorossia Bezzi is placed in the Anthracinae. The relationship of the Australian lomatiines to the world fauna is discussed, as are the relationships between the Australian genera. Docidomyia White is included in the Lomatiinae and is the sister group of all other genera of the subfamily: Comptosia Macquart sens.lat.; Doddosia Edwards, Oncodosia Edwards and Paramonovomyia Evenhuis. The current diagnosis of the Lomatiinae is changed to reflect the inclusion of Docidomyia. The two subgenera of Comptosia sensu Edwards, Aleucosia Edwards and Comptosia , were not each others' closest relatives in the strict consensus tree. Thus Comptosia as currently recognized is paraphyletic and the two subgenera are treated as genera, Aleucosia stat.nov. and Comptosia stat.nov.     

Phylogenetic relationships of the stromateoid fishes (Perciformes)

The phylogenetic relationships of all 16 genera (plus Psenes pellucidus) of the suborder Stromateoidei were estimated cladistically based on 43 osteological, myological, and external characters. Thirty equally parsimonious trees were obtained. Based on the strict consensus tree, Centrolophidae was nonmonophyletic, Psenopsis being placed as a sister group of a clade comprising Amarsipus, Ariomma, nomeids, Tetragonurus, and stromateids. Schedophilus formed a sister group relationship with Seriolella. The relationships among the Centrolophus, Hyperoglyphe, Icichthys, Tubbia, Schedophilus+Seriolella clade, and Psenopsis+Amarsipus+Ariomma+nomeids+Tetragonurus+stromateids clade were unresolved. Amarsipus, which is unique within the suborder in lacking a pharyngeal sac, was nested within the stromateoid clade, being a sister group of the clade including Ariomma, nomeids, Tetragonurus, and stromateids. The absence of a pharyngeal sac in Amarsipus was interpreted as a reversal, its presence in the Stromateoidei therefore being considered as a synapomorphy. Ariomma was placed as the sister group of a clade comprising nomeids, Tetragonurus, and stromateids. Monophyly of the Nomeidae and Stromateidae were supported by 2 and 11 synapomorphies, respectively.