Coastal sponge communities of the West Indian Ocean: taxonomic affinities, richness and diversity

Sponges assemblages were sampled in four coastal study regions (Malindi, Kenya; Quirimba Archipelago, northern Mozambique; Inhaca Island, Southern Mozambique and Anakao, Madagascar) in the west Indian Ocean. Sponge species were counted in multiple 0.5 m² quadrats at depths of between 0 and 20 m at a number of sites within localities within each region. Despite the relatively small areas sampled, sponge samples comprised a total of 130 species and 70 genera of the classes Demospongiae and Calcarea. Sponges are clearly a major taxon in these regions in terms of numbers of species, percentage cover or biomass, although their ecology in the west Indian Ocean is virtually unknown. Nearly half of the genera, e.g. Iotrochota, found were species with a so‐called Tethyan distribution. Most of the other genera were cosmopolitan, e.g. Clathria, but some were cold water (Coelosphaera), Indo‐Australian (Ianthella) or circum‐African (Crambe). Many of the species encountered in the present study occurred in at least two study regions, many in more and could occupy large areas of substratum. Some of these, e.g. Xestospongia exigua, are commonly found throughout the Indo‐west Pacific region where they also occupy much space. The endemicity of the shallow water sponge faunas in East Africa (20–25%) seem to be high within the Indo‐Pacific realm but are lower than northern Papua New Guinea. The tropical regions (Kenya and Northern Mozambique) were more speciose than subtropical regions (southern Mozambique and Madagascar) but not significantly more diverse (Shannon H′). Although latitude was not a major influence on sponge community patterns, hard substratum assemblages did form a cline from the tropics to Southern Mozambique, linked by Madagascar. Substratum nature (habitat) was most important in influencing the suite and number of species present. Sponge assemblages of soft substrata were much more dissimilar, both within and between habitats, than those on hard substrata. There was a predictable variability in species richness between hard substratum habitats: coral reefs being speciose and caves being less so. Our findings showed that both patterns and influences on species richness may be decoupled from those influencing diversity. In our data species richness, but not diversity, showed striking regional and bathymetric trends. In addition, sponge species richness mainly split at coral reef vs. non‐reef habitats, whilst diversity divided principally into assemblages on hard and soft substrata. We consider this dichotomy of findings between species richness and diversity values to be important, as these are two principal measures used for the interpretation of biodiversity.     

The song of the Seychelles Warbler Acrocephalus sechellensis, an island endemic

The Seychelles Warbler Acrocephalus sechellensis is a resident, cooperative breeder in a saturated, island environment, whose song structure diners significantly from European marshland Acrocephalus species. The song is transmitted within a more restricted frequency range, that which propagates most effectively through tropical forest. The Seychelles Warbler has developed a relatively short, simple song, used for territorial defence throughout the year, which is readily elicited by playback. Yet it also has a complex repertoire of song types, and song activity peaks before and declines during breeding, suggesting a sexual function. The demands of tropical island life are thus reflected in both the structure and function of song in the Seychelles Warbler.     

Phylogenetic affinities between eukaryotic cells and a thermophilic mycoplasma

Thermoplasma acidophilum, a thermophilic mycoplasma, has several unusual features suggesting a possible relationship to eukaryotic cells. One feature is a histone-like protein that is associated with the DNA, condensing it into subunits similar to those in eukaryotic chromatin. A second feature is an association of cytoplasmic proteins that resembles eukaryotic actin and myosin. These two components are widely distributed in different groups of eukaryotic cells, but are typically lacking in prokaryotic cells. Furthermore, T. acidophilum lacks cytochromes and respires by enzymes that apparently are not coupled to oxidative phosphorylation. This primitive type of respiration resembles that of microbodies, another feature which is represented in the cytoplasm of all groups of eukaryotic cells. Furthermore, since T. acidophilum lacks a cell wall and appears to have a primitive correlate of endocytosis, it would appear to be mechanically capable of acquiring a symbiotic mitochondrion. Thus, our observations are consistent with the symbiotic hypothesis for the origin of eukaryotic cells. We suggest that an organism similar to T. acidophilum was the host cell for the original symbiosis, becoming the nucleus and cytoplasm of modern eukaryotic cells.     

Speciation and rapid phenotypic differentiation in the yellow-rumped warbler Dendroica coronata complex

The relative importance of the Pleistocene glacial cycles in driving avian speciation remains controversial, partly because species limits in many groups remain poorly understood, and because current taxonomic designations are often based on phenotypic characteristics of uncertain phylogenetic significance. We use mtDNA sequence data to examine patterns of genetic variation, sequence divergence and phylogenetic relationships between phenotypically distinct groups of the yellow-rumped warbler complex. Currently classified as a single species, the complex is composed of two North American migratory forms (myrtle warbler Dendroica coronata coronata and Audubon's warbler Dendroica coronata auduboni), and two largely sedentary forms: Dendroica coronata nigrifrons of Mexico, and Dendroica coronata goldmani of Guatemala. The latter are typically considered to be races of the Audubon's warbler based on plumage characteristics. However, mtDNA sequence data reveal that sedentary Mesoamerican forms are reciprocally monophyletic to each other and to migratory forms, from which they show a long history of isolation. In contrast, migratory myrtle and Audubon's warblers form a single cluster due to high levels of shared ancestral polymorphism as evidenced by widespread sharing of mtDNA haplotypes despite marked phenotypic differentiation. Sedentary and migratory forms diverged in the early Pleistocene, whereas phenotypic differentiation between the two migratory forms has occurred in the Holocene and is likely the result of geographical isolation and subsequent range expansion since the last glaciation. Our results underscore the importance of Quaternary climatic events in driving songbird speciation and indicate that plumage traits can evolve remarkably fast, thus rendering them potentially misleading for inferring systematic relationships.     

The vocalizations of the Christmas Island Warbler Acrocephalus aequinoctialis, an island endemic

We describe the vocalizations of the Christmas Island Warbler Acrocephalus aequinoctialis , endemic to Christmas and Washington Islands, central Pacific Ocean, in the absence of other land birds and natural predators. Its vocal signals are simple when compared to most Acrocephalus. We explain this simplicity as the result of a lack of interspecific interactions, a monogamous life style, large permanent territories, open dry habitat and limited interaction among neighbouring individuals.     

Evolutionary history suggests rapid differentiation in the yellow-throated warbler Dendroica dominica

Molecular tools are reshaping many traditional paradigms concerning the timeframe of avian diversification in North America. Phylogeographic studies have become essential for guiding the emerging paradigms. However, the current pool of such studies tends not to be evenly dispersed across the landscape, which limits the generality of inferences. The southeastern United States is one region where the tempo and mode of recent avian diversification is poorly understood. One phylogeographic break in particular, the Tombigbee River discontinuity, divides eastern and western phylogroups in Alabama, and, though it is known to have influenced the phylogeographic patterns of some fish and reptiles, its role in promoting recent avian diversification is not well understood. Eastern and western morphological subspecies of the yellow-throated warbler Dendroica dominica divide along the phylogeographic break created by the Tombigbee River discontinuity suggesting that this bird was also affected by this vicariance. To determine whether the phylogeographic patterns of the yellow-throated warbler are consistent with this biogeographic barrier, I analyzed mitochondrial control region sequences of 109 yellow-throated warblers from across the species' range and, from a subset of these samples, sequences from a sex-linked nuclear gene. Considerable variation was uncovered, but most of this variation was found within rather than among populations or subspecies. A shallow phylogenetic tree, star-like haplotype network, and unimodal mismatch distribution all suggested a recent expansion. Coalescent modeling indicated that modern populations are derived from a single common ancestral population and that differences among subspecies in morphology, ecology, and migratory pathways are the result of recent and rapid evolution, possibly driven by selection.     

Phylogenetic affinities of the Flabelligeridae (Annelida, Polychaeta)

Cirratuliformia includes Acrocirridae, Cirratulidae, Ctenodrilidae, Flabelligeridae, Flotidae and Sternaspidae. The phylogenetic affinities have not been settled due to a limited availability of type or non-type material and the relationship between acrocirrids and flabelligerids have been problematical. In our study, the type material of all type species for all flabelligerid, and most acrocirrid genera have been studied and the morphological features have been used in a phylogenetic analysis. The results indicate that Acrocirridae, Ctenodrilidae, Fauveliopsidae, Flabelligeridae and Flotidae are monophyletic and that Sternaspidae falls within Cirratulidae; however, the latter conclusion might be reversed through increased taxon-sampling. The flabelligerid genera Brada, Flabelligera, Pherusa and Stylarioides each consists of several monophyletic groups and may be split. Conversely, Bradiella includes Diversibranchius, and the pelagic Buskiella includes Flota. The generic affinities of Poeobius remain uncertain, collecting better materials may resolve this issue.     

Phylogenetic, morphological, and chemotaxonomic incongruence in the North American endemic genus Echinacea

The study of recently formed species is important because it can help us to better understand organismal divergence and the speciation process. However, these species often present difficult challenges in the field of molecular phylogenetics because the processes that drive molecular divergence can lag behind phenotypic divergence. In the current study we show that species of the recently diverged North American endemic genus of purple coneflower, Echinacea, have low levels of molecular divergence. Data from three nuclear loci and two plastid loci provide neither resolved topologies nor congruent hypotheses about species-level relationships. This lack of phylogenetic resolution is likely due to the combined effects of incomplete lineage sorting, hybridization, and backcrossing following secondary contact. The poor resolution provided by molecular markers contrasts previous studies that found well-resolved and taxonomically supported relationships from metabolic and morphological data. These results suggest that phenotypic canalization, resulting in identifiable morphological species, has occurred rapidly within Echinacea. Conversely, molecular signals have been distorted by gene flow and incomplete lineage sorting. Here we explore the impact of natural history on the genetic organization and phylogenetic relationships of Echinacea.     

Migration, stopover and moult of the Great Reed Warbler Acrocephalus arundinaceus in Ghana, West Africa

We studied Great Reed Warblers Acrocephalus arundinaceus at two localities in Ghana during the winter. In the north (Tono), the birds arrived from late September and conducted a rapid moult soon after arrival. Towards the end of moult, birds accumulated fat and disappeared from the site. In the south (Tafo), birds arrived from mid-November in fresh plumage. This seemed to be the final wintering area as birds stayed there during the winter. In March-April they again accumulated fat, although only small amounts, before spring migration back to breeding areas.     

Phylogenetic position of Jaoa,a green algal genus endemic to China

Jaoa prasina, a freshwater green alga endemic to China, was collected from a stream in Hubei province, China. Unialgal cultivation, morphological observation, and phylogenetic analyses of small subunit ribosomal DNA and RuBisCO large subunit sequences were performed. When cultured on agar medium, the alga was irregularly filamentous, similar to marine species of Acrochaete. Aplanospores were observed on solid medium. A vesicular‐like thallus without rhizoids developed in liquid medium, similar to specimen development in natural habitats. Molecular phylogenetic analyses revealed that Jaoa was closely related to the marine genera Acrochaete Pringsheim and Ulvella Crouan & Crouan. The results suggested the genus Jaoa is a member of the family Ulvellaceae (Ulvophyceae), which contains mostly marine algae. The family name Jaoaceae should be abandoned. We speculate that Jaoa may have evolved from a marine Ulvellaceae ancestor.     

Phylogenetic affinities of tarsier in the context of primate Alu repeats

Related genomes tend to be colonized by the same or similar repetitive sequence elements. Analysis of these elements provides useful taxonomic information. We have sequenced Alu repeats from tarsier and compared them with those from strepsirhine prosimians (lemurs, sifaka, and galago) and the human genome. Tarsier elements cluster with Alu subfamilies from the human lineage. The oldest subfamily in tarsier and the most abundant human subfamilies share an RNA secondary structure motif which is absent both in the earliest dimeric Alu Jo and in the strepsirhine elements. These findings are consistent with the view that tarsiers form a sister clade with anthropoides rather than with other prosimians. Alu repeats in tarsier genome are relatively old, which indicates a dramatic slowdown or even an arrest of these elements' amplification about 20 Myr ago.     

Historical processes and environmental factors as determinants of inter-island differences in endemic faunas: the case of the Balearic Islands

Aim We describe current interisland similarities of endemic faunas, and elucidate the significance of historical factors and environmental ones in determining the pattern found. Location The six major islands of the Balearics (Western Mediterranean). Method An extensive review of all the endemic fauna ranging from platyhelminthes to mammals is made. From 568 presumed endemic species and subspecies, 230 full species with neither taxonomic nor distributional uncertainty are chosen. Inter-island similarities are determined using such a presence-absence matrix. Finally, relationships between the matrix of faunistic similarity and a number of matrices measuring environmental and historical factors are elucidated. Results Endemic fauna similarities depend clearly on historical factors. Dependence on environmental factors is unclear. Moreover, endemic fauna reveals two clear-cut clusters of islands within the Balearics: the Gymnesic Islands, in the NE, and the Pityusic Islands in the SW. Historical factors cluster the Balearic Islands in the same way. Contrasting, environmental variables show smoothed, no significant differences among the Gymnesics and the Pityusics. Main conclusions Pre-human flora (palynology) and fauna (bird and mammal fossil record) suggest that environmental differences among the Gymnesics and the Pityusics have now been reduced in comparison to the environmental differences at the Pleistocene and Holocene boundary. This environmental homogenization is likely related with human invasion. Historical effects of prehuman differences between Gymnesic and Pityusic Islands are still recognizable on endemic fauna. In contrast, there is no historical effects on interisland similarities using currently breeding birds (as an example of organisms well-dispersed and related to vegetation type). We explain the pattern of interisland similarities of endemic fauna as the result of the independent histories among the two islands groups. Contrasting, successive colonizations and extinctions would determine interisland similarities of breeding birds.     

Phylogenetic affinities and conservation status of Telaranea murphyae Paton in Britain

The United Kingdom Biodiversity Action Plans includes protection plans for 27 liverworts and 76 mosses. One of the most complicated examples of British plant rarity concerns the leafy liverwort Telaranea. Of the three species recognized in the literature for the British Isles, two (T. tetradactyla and T. murphyae) have been considered recent introductions to the British flora, because their occurrence is restricted to in or near botanic gardens. Both species have recently been transferred to the genus Tricholepidozia. Tricholepidozia murphyae, unlike any other bryophyte on the British Red List, is regarded as non-native, of unknown origin. We selected two molecular markers from different genomic compartments to fit in with existing datasets for Lepidoziaceae, in order to elucidate the origin and affinities of this enigmatic, non-native British endemic, and thus assist prioritization of conservation efforts. We sequenced multiple accessions of all three currently recognized British Telaranea and Tricholepidozia. Based on sequence data, while Telaranea europea is genetically isolated from all other sequenced Lepidoziaceae, it seems that Tricholepidozia murphyae merely represents a separate genetic introduction from the Austral T. tetradactlya/T. lindenbergii species group into the British Isles, and as such, in the UK it should be considered of low conservation priority. We thus synonymize T. murphyae under T. tetradactyla, while acknowledging that taxonomy within the T. tetradactlya/T. lindenbergii species complex still requires revision.     

Phylogenetic affinities and taxonomy of the Oligocene Diomedeoididae,and the basal divergences amongst extant procellariiform birds

The Palaeogene Diomedeoididae are amongst the earliest representatives of procellariiform birds (albatrosses, tubenoses, and allies). Although several fossils of these birds have been reported in the past, many details of their osteology remained unknown. Here we describe a comprehensive collection of diomedeoidid fossils from the Rupelian stratotype in Belgium, which was found more than 100 years ago. The material includes all major limb elements as well as other cranial and postcranial bones, and allows the recognition of previously unknown features of phylogenetic significance. Based on these new osteological data, diomedeoidids were for the first time subjected to a phylogenetic analysis, which resulted in a position outside a clade including Hydrobatidae (northern storm‐petrels), Pelecanoididae (diving‐petrels), and Procellariidae (fulmars, petrels, shearwaters, and allies), either as the sister taxon of Diomedeidae (albatrosses) or as that of all crown group Procellariiformes. The latter placement is better supported by the osteological evidence, and diomedeoidids lack several apomorphies of crown group Procellariiformes. Previously unrecognized derived features are reported that support a monophyletic Hydrobatidae, thus contradicting recent proposals that Oceanitinae (southern storm‐petrels) are the earliest diverging crown group Procellariiformes. The new fossils also have a bearing on the convoluted taxonomy of diomedeoidids, and Diomedeoides Fischer, 1985 is synonymized with Rupelornis van Beneden, 1871. Diomedeoides lipsiensis (Fischer, 1983) is synonymous with Rupelornis definitus (van Beneden, 1871), a species that exhibits a large size range. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 166 , 854–875.     

Zonation of the invertebrate fauna in a West Indian stream

Samples of the invertebrate fauna collected at ten points on a mountain stream in Trinidad reveal that the fauna is altitudinally zoned and that the apparent boundary between rhithron and potamon is below 30 m. This is very much lower than has previously been reported in the tropics.Summary General collections of the benthos and water striders were made at 10 points from 550-17 m altitude on the Arima River, Trinidad, a swift mountain stream. It was possible to conclude that 38 of the taxa that occurred commonly in some of the samples were probably single species. These displayed marked vertical zonation of the fauna and a change in the community that can be interpreted as the rhithron-potamon boundary at less than 30 m. This markedly lower than has previously been reported from the tropics.     

Genetic-geographic dispersion among North Indian populations and affinities of the Jats

Variation in 13 loci across North India has been mapped using principal components and generalized distance analysis. Significant clinal variation is documented for most systems, and genetic difference bears a relation to geographic distance especially along a north-west-to-southeast inclination. Both caste and geography exert influence over the historically contentious affinities of the Jats. Author order is alphabetical     

Phylogenetic affinities and taphonomy of Brooksella from the Cambrian of Georgia and Alabama, USA

Siliceous “star cobbles”, referred to the enigmatic genus Brooksella, are abundant in the Conasauga Formation of the Coosa River Valley of Alabama and Georgia, USA. Explaining the phylogenetic affinities and taphonomic history of Brooksella has been difficult and contentious. Brooksella has, at times, been referred to: 1, the cnidarian order Scyphomedusae; 2, the cnidarian class Protomedusae (order Brooksellida); 3, as algae; 4, as a trace fossil; and 5, as a feature of inorganic origin.Macroscopic, microscopic, and computer-assisted tomographic analysis of Brooksella from the Conasauga Formation suggests that the “star cobbles” represent exceptionally preserved body fossils of simple construction. Morphology of star cobbles is most consistent with a siliceous (hexactinellid) sponge interpretation. Specimens show wide morphologic variation, including gradational patterns, suggesting that a single species name (Brooksella alternata) should be used to embrace all forms described from the Coosa Valley. B. alternata includes specimens having a variable number of radially disposed lobes divided by radial grooves, and often a central opening inferred to be an osculum on one side. Lobes in many specimens terminate in small openings. Small craterlike structures, inferred to be ostia, are present on the external surface. Radial internal cavities occupy the lobes. Specimens from the Conasauga Formation have siliceous spicules preserved surficially and internally.The three-dimensional nature of most “star cobbles” suggests rapid fossil diagenesis, perhaps mediated by the activities of microbial consortia that quickly formed biofilms around the dead hosts.     

Phylogenetic affinities of Plagiocirrus Van Cleave and Mueller, 1932 with the description of a new species from the Pascagoula River, Mississippi

Plagiocirrus loboides n. sp. (Digenea: Opecoelidae) is described from Fundulus nottii, F. dispar blairae, F. chrysotus, and Notemigonus crysoleucas from the Pascagoula River in Mississippi. Plagiocirrus loboides differs from P. primus Van Cleave and Mueller, 1932, by having a longer postcecal space (14-25% of body length vs. about 7%); a more anterior vitellarium (extending at least to the middle of the ventral sucker vs. to its posterior margin); and larger eggs (51-71 microm long by 23-34 microm wide vs. 40-55 microm long by 30-35 microm wide). Plagiocirrus loboides differs from P. testeus Fritts, 1959, by having a long postcecal space (vs. < 5% of body length); irregular, oblique, contiguous testes (vs. strongly lobed, well separated, tandem testes); and a more extensive vitellarium. Plagiocirrus loboides differs from both congeners by having an ovary comprised of 3 or 4 distinct lobes rather than having an entire ovary. Plagiocirrus wuyienensis Wang, 1981, from Hemimyzon zebroidus in Fujian Province, China, is herein considered a species inquirenda because it has a Y-shaped excretory bladder. Molecular phylogenetic analysis of 28S rDNA gene fragments from P. loboides and 17 digenean species demonstrates that Plagiocirrus belongs in Opecoelidae.