Molecular phylogeny and character evolution in the Western Palaearctic Helicidae s.l. (Gastropoda: Stylommatophora)

In this study, we present a molecular phylogeny for the west Palaearctic Helicidae sensu lato based on sequence data from two mitochondrial (COI, 16S rDNA) and two nuclear (ITS-1, 18S rDNA) genes. Maximum likelihood analysis and Bayesian inference revealed well supported monophyletic clades partly conflicting traditional classifications. Based on these results, we propose the following system. The Western Palaearctic Helicidae s.l. consist of two families, Helicidae and Hygromiidae. Within the Helicidae, three well supported subfamilies can be recognised: the Helicinae, Ariantinae, and Helicodontinae. The Hygromiidae consist of three clades: the Hygromiinae, the Helicellinae, and a yet unnamed clade comprising the genera Sphincterochila and Cochlicella. We then used the phylogeny to study the evolution of anatomical, and ecological characters traditionally used for systematic classification. In the Helicidae s.l., two independent evolutionary transitions to life in xeric environments occurred, which allowed the occupation of new niches with a subsequent radiation of the Helicellinae-Cochlicella/Sphincterochila clade and the Helicinae. Whereas, the multiplication of the Glandulae mucosae is a synapomorphy of the Hygromiidae, the lovedart sac apparatus is present in all groups and thus, the trait cannot provide a synapomorphy for either families or subfamilies. Additionally, we evaluated the use of structural molecular genetic characters for taxonomic assessment. The presence of an unique loop region of the 16S rDNA gene and a short tandem repeat in the ITS-1 region provide independent evidence for the monophyly of these major two groups, and can be used for preliminary classification.     

Phylogeny of Orthotrichum s.l. and Ulota s.l. (Orthotrichaceae,Bryophyta): Insights into stomatal evolution

Orthotrichum Hedw. s.l. and Ulota Mohr s.l. are two of the most speciose genera of the xerophytic moss family Orthotrichaceae. We reconstructed the phylogeny of these two genera using three data matrices: (i) organellar genomes and 33 taxa; (ii) six loci from three genomes and 144 taxa; and (iii) two plastid loci and 163 taxa. The present phylogeny, based on the maximum sampling of genes or taxa to date, generally confirms the new classification of Orthotrichum and Ulota, and indicated that all Ulota species, except Ulota phyllantha Brid., form a clade and three lineages comprise the cryptoporous Orthotrichum clade. We provided new morphological characters that support the present division of the two genera. Ancestral state reconstruction of stoma indicates that superficial stomata in Orthotrichum represent a plesiomorphic character and semi-immersed stomata were derived from immersed stomata. The results also suggest that immersed stomata independently arose once in Orthotrichum, whereas semi-immersed stomata probably arose more than once. Molecular dating analysis reveals that the occurrence of immersed stomata is probably related to arid environments during the early Oligocene to late Miocene, whereas the appearance of semi-immersed stomata might be associated with the mesic–xeric or semiarid environments during the middle Miocene to Pliocene. Ancestral state reconstruction of habitat indicates that the saxicolous habitat is apomorphic and independently evolved multiple times in Orthotrichum and Ulota, which supports the former hypothesis. Considering morphological statistics, the development of the cryptopore in Orthotrichum could provide increased resilience to dry habitats, and might promote their habitat shift during evolution.     

Sexual dimorphism and sex ratios of two Australian dioecious species of alpine pineapple grass, Astelia alpina var. novaehollandiae and Astelia psychrocharis (Asteliaceae)

Sexual dimorphism and male biased sex ratios have been predicted for dioecious plants experiencing the limited conditions for growth and reproduction found in many alpine environments. To test these predictions, the reproductive ecology of two congeneric, co-occurring, dioecious, clonal, species was examined in the subalpine and alpine zones of Kosciuszko National Park, southeastern Australia. Specifically, plant size (vegetative cover of plants in quadrats), floral display (number of flowers per inflorescence, number of inflorescences per quadrat) and sex ratios (proportion of females in quadrats with flowers) were examined in ten populations of Astelia psychrocharis (Asteliaceae) and nine populations of Astelia alpina var. novae-hollandiae (Asteliaceae). Sexual dimorphism did occur, with males having more flowers per inflorescence (106% more flowers for A.alpina males and 12% more for A.psychrocharis males compared to females) and more inflorescences per quadrat than females (78% more inflorescences for A.alpina males and 46% more inflorescences for A.psychrocharis males compared to females). Plant size did not differ between male and female quadrats of either species, nor were there male biased sex ratios. However, plant size was related to flowering status in A.psychrocharis with the 65 quadrats that did not flower having lower vegetative cover than the 175 flowering quadrats indicating that there may be a minimum size/ cover required prior to flowering in this species. For A.alpina, all but two of the 185 quadrats randomly sampled flowered. There was no effect of altitude on plant size and very little effect of altitude on floral display for either species, apart from a slight increase in the number of inflorescences per quadrat with increasing altitude for A.psychrocharis, and slight decrease in number of flowers per inflorescence with increasing altitude for A.alpina females.     

Molecular phylogeny of telenomine egg parasitoids (Hymenoptera: Platygastridae s.l.: Telenominae): evolution of host shifts and implications for classification

Parasitoid wasps of the subfamily Telenominae (Hymenoptera: Platygastroidea, Platygastridae) develop as immatures within the eggs of other insects (Lepidoptera, Hemiptera, Diptera and Neuroptera). Rearing records indicate that individual species are restricted to attack hosts within only one of these four main groups. We conducted a phylogenetic analysis of the group using sequence data from multiple genes (18S, 28S, COI, EF‐1α) to assess the pattern of shifts among host groups and to test the monophyly of and relationships among genera and species‐groups. Telenominae sensu Masner—that is, including only the nominate tribe Telenomini—is not monophyletic. Representatives of the Psix group of genera (Psix Kozlov & Lê and Paratelenomus Dodd) form a monophyletic group that is sister to Gryon Haliday (Scelioninae: Gryonini) and are excluded from the subfamily. The remaining telenomines are monophyletic. The genus Phanuromyia Dodd and the crassiclava group of Telenomus Haliday, both recorded as parasitoids of planthopper eggs (Hemiptera: Auchenorrhyncha, Fulgoroidea), form a monophyletic group that is sister to all other telenomines exclusive of the Psix group. Twenty‐nine species of the crassiclava and aradi groups of Telenomus are transferred to Phanuromyia as new combinations. Basal elements of the remaining species are all in groups reared from the eggs of true bugs (Heteroptera), primarily the stink bugs (Pentatomoidea) and seed bugs (Lygaeoidea). A shift to parasitism of lepidopteran eggs evolved within a single clade, occurring either one or two times. From this clade a small group of species, the Telenomus tabanivorus group, subsequently shifted to parasitism of egg masses of true flies (Tabanidae and Stratiomyiidae). Aholcus Kieffer and Platytelenomus Dodd both belong to the clade of lepidopteran parasitoids and are considered as junior synonyms of Telenomus (new synonymy for Aholcus). The monophyletic status of the two core genera, Telenomus and Trissolcus could not be resolved using these data. The phylogenetic pattern of host shifts suggests comparisons among taxa that may be fruitful in elucidating mechanisms by which parasitoids locate their hosts, the proximate factors that determine the host range, and the changes in these factors that influence host changes.     

Anchored hybrid enrichment provides new insights into the phylogeny and evolution of longhorned beetles (Cerambycidae)

Cerambycidae is a species‐rich family of mostly wood‐feeding (xylophagous) beetles containing nearly 35 000 known species. The higher‐level phylogeny of C erambycidae has never been robustly reconstructed using molecular phylogenetic data or a comprehensive sample of higher taxa, and its internal relationships and evolutionary history remain the subjects of ongoing debate. We reconstructed the higher‐level phylogeny of C erambycidae using phylogenomic data from 522 single copy nuclear genes, generated via anchored hybrid enrichment. Our taxon sample (31 C hrysomeloidea, four outgroup taxa: two C urculionoidea and two C ucujoidea) included exemplars of all families and 23 of 30 subfamilies of C hrysomeloidea (18 of 19 non‐chrysomelid C hrysomeloidea), with a focus on the large family C erambycidae. Our results reveal a monophyletic C erambycidae s.s. in all but one analysis, and a polyphyletic C erambycidae s.l. When monophyletic, C erambycidae s.s. was sister to the family D isteniidae. Relationships among the subfamilies of C erambycidae s.s. were also recovered with strong statistical support except for C erambycinae being made paraphyletic by Dorcasomus A udinet‐S erville (D orcasominae) in the nucleotide (but not amino acid) trees. Most other chrysomeloid families represented by more than one terminal taxon – C hrysomelidae, D isteniidae, V esperidae and O rsodacnidae – were monophyletic, but M egalopodidae was rendered paraphyletic by Cheloderus G ray (O xypeltidae). Our study corroborates some relationships within C hrysomeloidea that were previously inferred from morphological data, while also reporting several novel relationships. The present work thus provides a robust framework for future, more deeply taxon‐sampled, phylogenetic and evolutionary studies of the families and subfamilies of C erambycidae s.l. and other C hrysomeloidea.     

Molecular cloning and characterization of a moss (Ceratodon purpureus) nonsymbiotic hemoglobin provides insight into the early evolution of plant nonsymbiotic hemoglobins

Nonsymbiotic hemoglobins (nsHbs) are widespread in plants including bryophytes. Bryophytes (such as mosses) are among the oldest land plants, thus an analysis of a bryophyte nsHb is of interest from an evolutionary perspective. However, very little is known about bryophyte nsHbs. Here, we report the cloning and characterization of an nshb gene (cerhb) from the moss Ceratodon purpureus. Sequence analysis showed that cerhb is interrupted by 3 introns in identical position as all known plant nshb genes, which suggests that the ancestral nshb gene was interrupted by 3 introns. Expression analysis showed that cerhb expresses in protonemas and gametophytes growing in normal conditions and that it overexpresses in protonemas subjected to osmotic (sucrose), heat-shock, cold-, and nitrate-stress conditions. Also, modeling of the Ceratodon nsHb (CerHb) tertiary structure suggests that CerHb is hexacoordinate and that it binds O(2) with high affinity. Comparative analysis of the predicted CerHb with native rice Hb1 and soybean leghemoglobin a structures revealed that the major evolutionary changes that probably occurred during the evolution of plant Hbs were 1) a hexacoordinate to pentacoordinate transition at the heme prosthetic group, 2) a length decrease at the CD-loop and N- and C-termini regions, and 3) the compaction of the protein into a globular structure.     

The amphioxus genome provides unique insight into the evolution of immunity

Immune systems evolve as essential strategies to maintain homeostasis with the environment, prevent microbial assault and recycle damaged host tissues. The immune system is composed of two components, innate and adaptive immunity. The former is common to all animals while the latter consists of a vertebrate-specific system that relies on somatically derived lymphocytes and is associated with near limitless genetic diversity as well as long-term memory. Deuterostome invertebrates provide a view of immune repertoires in phyla that immediately predate the origins of vertebrates. Genomic studies in amphioxus, a cephalochordate, have revealed homologs of genes encoding most innate immune receptors found in vertebrates; however, many of the gene families have undergone dramatic expansions, greatly increasing the innate immune repertoire. In addition, domain-swapping accounts for the innovation of new predicted pathways of receptor function. In both amphioxus and Ciona, a urochordate, the VCBPs (variable region containing chitin-binding proteins), which consist of immunoglobulin V (variable) and chitin binding domains, mediate recognition through the V domains. The V domains of VCBPs in amphioxus exhibit high levels of allelic complexity that presumably relate to functional specificity. Various features of the amphioxus immune repertoire reflect novel selective pressures, which likely have resulted in innovative strategies. Functional genomic studies underscore the value of amphioxus as a model for studying innate immunity and may help reveal how unique relationships between innate immune receptors and both pathogens and symbionts factored in the evolution of adaptive immune systems.     

Molecular phylogeny reveals the repeated evolution of complex male genital traits in the New Zealand moth genus Izatha (Lepidoptera: Xyloryctidae)

Male genitalia are among the most rapidly evolving and divergent morphological structures and sexual selection is known to drive this phenomenon in many taxa. Because of their diversity, even within a single genus, genital characters are frequently used to infer relationships among closely‐related species. Moths within the genus Izatha (Xyloryctidae) are ideal candidates for investigating the phylogenetic patterns of genital evolution as they display great variation in male genital structure and complexity. We determined the evolutionary relationships among 31 species of Izatha by constructing a molecular phylogeny of the genus based on the mitochondrial cytochrome oxidase subunit I gene and the isocitrate dehydrogenase and carbamoylphosphate synthase domain protein nuclear genes. This allowed estimations of ancestral male genital character states and patterns of male genital diversification using maximum‐likelihood models. The genus is divided into two well‐supported clades and two poorly supported clades at the root of the phylogeny with incomplete phylogenetic resolution within two species groups, likely due to rapid speciation. Izatha display a number of apomorphic phallic traits including cornuti (sclerotized spines) which are either discharged into the female during copulation (deciduous cornuti) or fixed to the male phallus (compound and fish‐hook cornuti). Within the genus, there is a reduction of secondary genital characters – the uncus and gnathos – but an elaboration of another grasping structure, the juxta; the potential origin and functionality of these male genital traits are discussed. Overall, some male genital characters provided a good indication of species relationships; however, several parts of the complex male genitalia of Izatha show evidence of homoplasy and convergence highlighting the problems of using these traits in determining species relationships. Additionally, this convergence has highlighted that complex genital structures may evolve repeatedly and independently within a lineage.     

Molecular phylogenetic and molecular dating of the New Zealand Gleicheniaceae

The Gleicheniaceae are an ancient family of ferns, with three of the six extant genera occurring in New Zealand:Dicranopteris, Gleichenia, andSticherus. The biogeographic origins of this family in New Zeland are unknown, and the taxonomy ofGleichenia in particular is still unclear. To address aspects of these two issues, DNA sequences from thetrnL-trnF locus and therbcL gene were produced for all of the common Gleicheniaceae species in New Zealand, as well as forGleichenia alpina from Tasmania andSticherus cryptocarpus from Chile. SeveraltrnL-trnF haplotypes were found amongst New ZealandG. dicarpa. One of these haplotypes was also observed in TasmanianG. alpina, while the other New ZealandG. dicarpa trnL-trnF haplotypes were more similar to those ofG. microphylla. These results suggest the taxonomy of New ZealandGleichenia may be more complex than presently recognized. Molecular dating of therbcL sequences with the program r8s rejected vicariant explanations for the disjunct distributions between New Zealand and elsewhere for each ofDicranopteris, Gleichenia, andSticherus. However, the direction of the inferred long-distance dispersal was not resolved.     

Molecular phylogeny and evolutionary history of the tit-tyrants (Aves: Tyrannidae)

Tit-tyrants of the genus Anairetes presently consist of six species; five inhabit various regions along the Andean cordillera of South America and one is endemic to the Juan Fernandez Islands off the coast of Chile. Data from mtDNA ND2 and Cyt b sequences were used to construct a phylogeny for all Anairetes species as well as Uromyias agilis, a closely related genus, and Stigmatura as an outgroup, to determine their relationships and history of radiation in South America. Results strongly supported the following paired relationships: A. nigrocristatus-A. reguloides, A. flavirostris-A. alpinus, and A. parulus-A. fernandezianus. This dataset, however, could not resolve basal nodes; therefore relationships among these pairs remains obscure. Moreover the genus Uromyias, controversially separated on morphological criteria from Anairetes, fell within the Anairetes clade, although its exact position could not be ascertained with confidence. The molecular data indicate that this group probably radiated within the past 2 million years, concomitant with highly accentuated cycles of global climatic change. Certain high altitude areas within the Andes may have been stable during global climatic changes and may have served as refugia during the Plio-Pleistocene.     

Molecular phylogeny and biogeographic history of the piculets (Piciformes: Picumninae)

The subfamily Picumninae (piculets) includes 3 genera and 30 species of tiny and short-tailed woodpeckers with a pantropical distribution. Within the Picumninae, two cases of intercontinentally disrupted distributions at the genus level occur. The first one concerns the genus Sasia (one species in Africa and two in southeast Asia) while the second concerns Picumnus (one species in southeast Asia and 25 in South America). These disrupted distributions, as well as several morphological differences, have lead some authors to place the African representative of Sasia and the southeast Asian representative of Picumnus in their own monotypic genera ( Verreauxia and Vivia , respectively). To address the taxonomic status and biogeographic history of the piculets, we sequenced 2676 bp of DNA from one mitochondrial (ND2) and two nuclear markers (myoglobin intron 2 and β-fibrinogen intron 7). Monophyly of Picumninae could not be recovered with confidence, while monophyly of Sasia and Picumnus were always strongly supported. Molecular dating analyses revealed that the splits both between the African and Indo-Malayan Sasia and between the New World and Old World Picumnus occurred at ca 7.9 Myr BP. This time corresponds to the beginning of the formation of the northern Hemisphere ice sheets and the accompanying expansion of grasslands throughout the world. The spread of open areas in the northern parts of Eurasia and America prevented gene flow between tropical forest birds, such as the piculets, in Africa, southeast Asia and South America, respectively.     

Molecular phylogeny and diversification history of Prosopis (Fabaceae: Mimosoideae)

The genus Prosopis is an important member of arid and semiarid environments around the world. To study Prosopis diversification and evolution, a combined approach including molecular phylogeny, molecular dating, and character optimization analysis was applied. Phylogenetic relationships were inferred from five different molecular markers ( mat K- trn K, trn L- trn F, trn S- psb C, G3pdh, NIA). Taxon sampling involved a total of 30 Prosopis species that represented all Sections and Series and the complete geographical range of the genus. The results suggest that Prosopis is not a natural group. Molecular dating analysis indicates that the divergence between Section Strombocarpa and Section Algarobia plus Section Monilicarpa occurred in the Oligocene, contrasting with a much recent diversification (Late Miocene) within each of these groups. The diversification of the group formed by species of Series Chilenses, Pallidae, and Ruscifoliae is inferred to have started in the Pliocene, showing a high diversification rate. The moment of diversification within the major lineages of American species of Prosopis is coincident with the spreading of arid areas in the Americas, suggesting a climatic control for diversification of the group. Optimization of habitat parameters suggests an ancient occupation of arid environments by Prosopis species.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 93 , 621–640.     

Molecular phylogeny and evolution of the AsianAconitum subgenusAconitum (Ranunculaceae)

Classification of the genusAconitum (Ranunculaceae) has long been considered quite difficult because its species show high levels of morphological and ecological variability. The molecular phylogeny of Asian aconites,Aconitum subgenusAconitum was, therefore, studied based on RFLP and sequences of the intergenic spacer between thetrnL (UAA) 3′ exon andtrnF (GAA), and of thetrnL intron, of the chloroplast DNA. UsingAconitum subgenusLycoctonum as an outgroup, we obtained a statistically reliable molecular tree composed of six clades branched radiatively at the very base. There are three clades of Japanese aconites, a single clade of the species of Yunnan and Himalayas, and two clades of Siberian plants. All the tetraploid taxa of Japan we studied did not show any difference based on the molecular characters analyzed, though they have been classified into many taxa. Evolution and phytogeography of the Asian aconites as well as the phylogeny are discussed.     

Molecular phylogeny and morphological evolution of the Acantharia (Radiolaria)

Acantharia are ubiquitous and abundant rhizarian protists in the world ocean. The skeleton made of strontium sulphate and the fact that certain harbour microalgal endosymbionts make them key planktonic players for the ecology of marine ecosystems. Based on morphological criteria, the current taxonomy of Acantharia was established by W.T. Schewiakoff in 1926, since when no major revision has been undertaken. Here, we established the first comprehensive molecular phylogeny from single morphologically-identified acantharian cells, isolated from various oceans. Our phylogenetic analyses based on 78 18S rDNA and 107 partial 28S rDNA revealed the existence of 6 main clades, sub-divided into 13 sub-clades. The polyphyletic nature of acantharian families and genera demonstrates the need for revision of the current taxonomy. This molecular phylogeny, which highlights the taxonomic relevance of specific morphological criteria, such as the presence of a shell and the organisation of the central junction, provides a robust phylogenetic framework for future taxonomic emendation. Finally, mapping all the existing environmental sequences available to date from different marine ecosystems onto our reference phylogeny unveiled another 3 clades and improved the understanding of the biogeography and ecology of Acantharia.     

A total-evidence phylogeny of ticks provides insights into the evolution of life cycles and biogeography.

We inferred the phylogeny of 33 species of ticks from the subfamilies Rhipicephalinae and Hyalomminae from analyses of nuclear and mitochondrial DNA and morphology. We used nucleotide sequences from 12S rRNA, cytochrome c oxidase I, internal transcribed spacer 2 of the nuclear rRNA, and 18S rRNA. Nucleotide sequences and morphology were analyzed separately and together in a total-evidence analysis. Analyses of the five partitions together (3303 characters) gave the best-resolved and the best-supported hypothesis so far for the phylogeny of ticks in the Rhipicephalinae and Hyalomminae, despite the fact that some partitions did not have data for some taxa. However, most of the hidden conflict (lower support in the total-evidence analyses compared to that in the individual analyses) was found in those partitions that had taxa without data. The partitions with complete taxonomic sampling had more hidden support (higher support in the total-evidence analyses compared to that in the separate-partition analyses) than hidden conflict. Mapping of geographic origins of ticks onto our phylogeny indicates an African origin for the Rhipicephalinae sensu lato (i.e., including Hyalomma spp.), the Rhipicephalus-Boophilus lineage, the Dermacentor-Anocentor lineage, and the Rhipicephalus-Booophilus-Nosomma-Hyalomma-Rhipicentor lineage. The Nosomma-Hyalomma lineage appears to have evolved in Asia. Our total-evidence phylogeny indicates that (i) the genus Rhipicephalus is paraphyletic with respect to the genus Boophilus, (ii) the genus Dermacentor is paraphyletic with respect to the genus Anocentor, and (iii) some subgenera of the genera Hyalomma and Rhipicephalus are paraphyletic with respect to other subgenera in these genera. Study of the Rhipicephalinae and Hyalomminae over the last 7 years has shown that analyses of individual datasets (e.g., one gene or morphology) seldom resolve many phylogenetic relationships, but analyses of more than one dataset can generate well-resolved phylogenies for these ticks.     

Increased taxon sampling provides new insights into the phylogeny and evolution of the subclass Calcaronea (Porifera,Calcarea)

Calcaronean sponges are acknowledged to be taxonomically difficult, and generally, molecular data does not support the current morphology-based classification. In addition, molecular markers that have been successfully employed in other sponge taxa (e.g., COI mtDNA) have proven challenging to amplify due to the characteristics of calcarean mitochondrial genomes. A short fragment of the 28S rRNA gene (C-region) was recently proposed as the most phylogenetically informative marker to be used as a DNA barcode for calcareous sponges. In this study, the C-region and a fragment of the 18S rRNA gene were sequenced for a wide range of calcareous taxa, mainly from the subclass Calcaronea. The resulting dataset includes the most comprehensive taxon sampling of Calcaronea to date, and the inclusion of multiple specimens per species allowed us to evaluate the performance of both markers, as barcoding markers. 18S proved to be highly conserved within Calcaronea and does not have sufficient signal to resolve phylogenetic relationships within the subclass. Although the C-region does not exhibit a “proper” barcoding gap, it provides good phylogenetic resolution for calcaronean sponges. The resulting phylogeny supports previous findings that the current classification of the subclass Calcaronea is highly artificial, and with high levels of homoplasy. Furthermore, the close relationship between the order Baerida and the genus Achramorpha suggest that the order Baerida should be abandoned. Although the C-region currently represents the best available marker for phylogenetic and barcoding studies in Calcaronea, it is necessary to develop additional molecular markers to improve the classification within this subclass.     

Molecular phylogeny,pigment composition,toxicology and life history of Pseudochattonella cf. verruculosa (Class Dictyochophyceae) from Wellington Harbour,New Zealand

Pseudochattonella verruculosa is a heterokont flagellate and has frequently been found associated with multi-species harmful algal blooms in Wellington Harbour. In this study the partial sequences of the nuclear encoded LSU rDNA and the large subunit of ribulose bisphosphate carboxylase (rbcL) of Pseudochattonella isolated from Wellington Harbour indicate that it is similar to P. verruculosa, while sequences of mitochondrial encoded COI, are similar to those of Pseudochattonella farcimen. As with P. farcimen, the Wellington Pseudochattonella lacked violaxanthin, lutein and anteroxanthin, three pigments detected only in P. verruculosa. The Wellington isolate also contains zeaxanthin which is absent in P. farcimen. Among all Pseudochattonella, cells of the Wellington isolate are the most variable in terms of both size and shape. Mucocysts of the Wellington Pseudochattonella also have the greatest degree of variation – from small, ‘bullet’-shape to large oval, oblong or ‘sausage’-like. In the sexual reproduction phase two gametes of the Wellington isolate fuse to form a zygote which gives rise to a large multi-nucleate cell. At times two or more of these large multi-nucleate cells fuse further to form a ‘massive’, plasmodium-like aggregate (up to 200 μm long). Positive feeding and toxicity tests on rotifers confirmed that the Wellington Pseudochattonella is cytotoxic and probably also contributed to the May 2010 fish kills. As molecular phylogenies do not conclusively support the separation of the Wellington Harbour Pseudochattonella from P. verruculosa or P. farcimen, it is tentatively named as Pseudochattonella cf. verruculosa.     

African Y chromosome and mtDNA divergence provides insight into the history of click languages

BACKGROUND: About 30 languages of southern Africa, spoken by Khwe and San, are characterized by a repertoire of click consonants and phonetic accompaniments. The Jumid R:'hoansi (!Kung) San carry multiple deeply coalescing gene lineages. The deep genetic diversity of the San parallels the diversity among the languages they speak. Intriguingly, the language of the Hadzabe of eastern Africa, although not closely related to any other language, shares click consonants and accompaniments with languages of Khwe and San. RESULTS: We present original Y chromosome and mtDNA variation of Hadzabe and other ethnic groups of Tanzania and Y chromosome variation of San and peoples of the central African forests: Biaka, Mbuti, and Lisongo. In the context of comparable published data for other African populations, analyses of each of these independently inherited DNA segments indicate that click-speaking Hadzabe and Jumid R:'hoansi are separated by genetic distance as great or greater than that between any other pair of African populations. Phylogenetic tree topology indicates a basal separation of the ancient ancestors of these click-speaking peoples. That genetic divergence does not appear to be the result of recent gene flow from neighboring groups. CONCLUSIONS: The deep genetic divergence among click-speaking peoples of Africa and mounting linguistic evidence suggest that click consonants date to early in the history of modern humans. At least two explanations remain viable. Clicks may have persisted for tens of thousands of years, independently in multiple populations, as a neutral trait. Alternatively, clicks may have been retained, because they confer an advantage during hunting in certain environments.