Received: 30 April 2010 / Accepted: 18 June 2010 / Published online: 01 December 2010
A warning for ecologists and conservation biologists using species checklists: How the European marine fauna ‘lost’ all of its 16 Discodoris species (Mollusca: Gastropoda)Download PDFAbstract
The European marine fauna used to be considered to include 16 species of Discodoris sea slugs until a recent worldwide revision demonstrated that there is not a single Discodoris species in European waters. This exemplary case illustrates the fact that species checklists do not accurately represent biodiversity unless they are based on sound taxonomic work in which (1) the status of every available species name has been addressed, i.e. whether it is valid, synonymous, or of doubtful application, and (2) classification reflects phylogenetic relationships. It is argued that taxonomic revisions are critically needed, because the status of species names can only be addressed properly through revisions. It is discussed that fields which depend on taxonomic data, such as conservation biology and ecology, might be affected deeply if problematic species names (synonyms and nomina dubia) have not been recognized. Consequently, it is proposed that a taxon that has not been revised be red-flagged in checklists, so that non-taxonomists will know which species names should be applied with caution or not at all.
Received: 04 April 2011 / Accepted: 26 August 2011 / Published online: 22 September 2011
A novel method to calculate climatic niche similarity among species with restricted ranges—the case of terrestrial Lycian salamandersDownload PDFAbstract
Within the framework of the present study we test whether climatic niche similarity can be identified in a monophyletic group of species inhabiting remarkably restricted ranges by pooling presence data of all species into a single concatenated data set and subsequently jackknifing single species. We expect that, when the jackknifed species differs markedly in its climatic niche from all other species, this approach will result in increased niche homogeneity, allowing assessments of niche divergence patterns. To test our novel jackknife approach, we developed species distribution models for all members of Lycian salamanders (genus Lyciasalamandra), native to Turkey and the adjacent Aegean islands using Maxent. Degrees of niche similarity among species were assessed using Schoener’s index. Significance of results was tested using null-models. The degree of niche similarity was generally high among all seven species, with only L. helverseni differing significantly from the others. Carstic lime stones providing specific microhabitat features may explain the high degree of niche similarity detected, since the variables with the highest explanative power in our models (i.e. mean temperature, and precipitation of the coldest quarter) corresponded well with salamander natural history observations, supporting the biologically plausibility of the results. We conclude that the jackknife approach presented here for the first time allows testing for niche similarity in species inhabiting restricted ranges and with few species records available. Our results strongly support the view that detailed natural history information and knowledge of microhabitats is crucial when assessing possible climate change impacts on species.
Received: 21 June 2010 / Accepted: 14 December 2010 / Published online: 13 January 2011
Sympatry in Mantophasmatodea, with the description of a new species and phylogenetic considerationsDownload PDFAbstract
We describe a new genus of Mantophasmatodea, Viridiphasma gen. n. (Austrophasmatidae), represented by one new species, V. clanwilliamense sp. n. The new species differs from previously described species in features of the male and female postabdomen including the genitalia, in morphometrics and details of colouration. The new species occurs syntopically with another austrophasmatid, Karoophasma biedouwense Klass et al., 2003; this is the first well-documented case of sympatry of two mantophasmatodean species. We therefore survey the morphological differences between these two species, document the absence of any morphological evidence of hybridisation, and also report on differences in life history. While a previous molecular phylogeny using COI and 16S genes ambiguously placed V. clanwilliamense sp. n. near the base of Austrophasmatidae (but not as sister to all other Austrophasmatidae), morphological characters strongly support V. clanwilliamense sp. n. to be the sister taxon of a clade comprising all remaining Austrophasmatidae. This phylogenetic placement challenges the current hypothesis of a linear north-to-south diversification of Austrophasmatidae.
Received: 20 April 2011 / Accepted: 02 October 2011 / Published online: 20 October 2011
Allopatric divergence and secondary contacts in Euphorbia spinosa L: Influence of climatic changes on the split of the speciesDownload PDFAbstract
Euphorbia spinosa, a perennial xerophilous shrub naturally distributed across the Italian peninsula, was selected for examination of the role of the Ligurian Alps and Apennines in glacial survival. The Italian Peninsula is considered to be one of the principal glacial refugia in Europe, but few plant population genetic and phylogeography studies have been undertaken in this region. The combined analysis of chloroplast and nuclear loci (ITS, cpSSR and ISSR) enabled us to detect extensive DNA variation and proved to be a very powerful tool for the reconstruction of the phylogeography. Molecular data support the hypothesis of a long-term separation of the Northwestern (Maritime Alps, Sardinia, Corsica, Northern Apennines) and Southeastern (Southern Apennines and Balkan area) lineages in glacial refugia. The existence of allopatrically fragmented lineages is most probably the result of isolation in different glacial refugia, possibly due to the Last Glacial Maximum cooling and the topographic complexity of the Italian peninsula. The most plausible hypothesis assumes the formation of two migration paths during more recent periods: the first one starting with southward migration and the second one moving northwards. The Central Apennines should be considered the confluence of migration routes radiating from separate refugia according to this hypothesis.
Received: 06 August 2010 / Accepted: 21 February 2011 / Published online: 05 March 2011
Hypotheses on rostral shield evolution in fossorial lizards derived from the phylogenetic position of a new species of Paracontias (Squamata, Scincidae)Download PDFAbstract
In squamate reptiles the rostral shield constitutes one of the most advanced cases of reduction in the number of scales in the rostral region, an evolutionary trend clearly associated with a burrowing lifestyle. This structure is characterized by the fusion of the rostral scale with all adjacent scales into a large, smooth and conical plate covering the snout, totally encompassing the nostrils, with a horizontal groove running posteriorly from either nostril. In lizards this structure evolved several times independently, in various lineages of limbless skinks and in the family Dibamidae. We performed a multilocus phylogenetic analysis of combined mitochondrial and nuclear DNA sequences from the fossorial genus Paracontias, including P. vermisaurus, a new species described herein under an integrative taxonomic approach. The resulting phylogeny supports monophyly of Paracontias, with the following internal topology: [P. kankana (P. vermisaurus sp. n. (((P. minimus + P. brocchii) (P. manify + P. hildebrandti)) (P. rothschildi + P. fasika)))]. The molecular data, coupled with a comparative morphological study, allows us to investigate the evolution of the snout scales into a single large rostral shield in Paracontias. We discuss the evolutionary processes through which the rostral shield may have originated (e.g. fusion of scales, number and order of steps involved), and conclude that intuitive and apparently obvious hypotheses for scale homologies based on position and size only (as usually formulated in squamate taxonomy) may be highly misleading, even in closely related species. We develop the hypothesis that the rostral shield may provide several functional advantages for fossorial species in facilitating burrowing and protecting the head from strong physical stress, e.g. smoother surface reducing friction between the tegument and the substrate, reduction in the number of flexible sutures resulting in strengthened tegument, and the rostral tip likely playing a role as a shock-absorbing buffer.
Received: 21 July 2010 / Accepted: 28 February 2011 / Published online: 13 March 2011
A new perspective on the evolution of white blister rusts: Albugo s.str. (Albuginales; Oomycota) is not restricted to Brassicales but also present on FabalesDownload PDFAbstract
For almost all groups of pathogens, unusual and rare host species have been reported. Often, such associations are based on single or few collections only, which are frequently hard to access. Many of them later prove to be due to misidentification of the host, the pathogen, or both. Therefore, such reports are often disregarded, or treated anecdotally in taxonomic and phylogenetic studies, regardless of their potential importance to unravelling the evolution of the entire group. Concerning oomycete biotrophs there are several reports of unusual and rare hosts for hardly known pathogens. In the order Fabales, for example, a single species of Albugo, A. mauginii, was described as parasitic to Onobrychis crista-galli about 80 years ago, but not recorded again. All other confirmed members of Albugo s.str. are parasitic to representatives of the families Brassicaceae, Capparaceae, Cleomaceae, and Resedaceae in the order Brassicales. In the present study, molecular phylogenetic analysis of cox2 mtDNA sequences and morphological investigations on an original specimen confirmed the occurrence of a member of Albugo on Fabaceae hosts, with the characteristic thin wall of the secondary sporangia, which is almost uniform in thickness. In phylogenetic analyses the species results as embedded within Albugo s.str. Therefore, it is concluded that the natural host range of Albugo s.str. extends from Brassicales to Fabales via host jumping. Our results underscore that unrevised reports of pathogens from unusual hosts should be reconsidered carefully to obtain a more complete picture of pathogen diversity and evolution.
Received: 25 January 2011 / Accepted: 26 May 2011 / Published online: 19 June 2011
Interactive 3D anatomy and affinities of the Hyalogyrinidae, basal Heterobranchia (Gastropoda) with a rhipidoglossate radulaDownload PDFAbstract
Whereas Hyalogyrina Marshall, 1988 was originally considered a skeneid vetigastropod, the family Hyalogyrinidae Warén & Bouchet, 1993 has later been classified as basal Heterobranchia despite their rhipidoglossate radula. In order to evaluate this placement and to shed more light on the origin of all higher Gastropoda, we investigated five representatives of all three nominal hyalogyrinid genera by means of semithin serial sectioning and computer-aided 3D reconstruction of the respective anatomy, which we present in an interactive way. In general the morphological features (shell, external morphology, anatomy) fully confirm the placement of Hyalogyrinidae in the Heterobranchia, but in particular the conditions of the genital system vary substantially within the family. The ectobranch gill of Hyalogyrinidae is shared with Valvatidae, Cornirostridae, and Xylodisculidae; consequently all these families are united in Ectobranchia Fischer, 1884. The rhipidoglossate hyalogyrinid radula suggests independent acquisition of taenioglossate radulae in the Caenogastropoda and other Ectobranchia. Therefore, the origin of the Heterobranchia—and thus of all higher gastropods—looks to have taken place already on the rhipidoglossate, i.e. the ‘archaeogastropod’, level of evolution. Ectobranchia are considered the first extant offshoot of the Heterobranchia; implications for the stem species of the latter are outlined.
Received: 05 July 2010 / Accepted: 15 July 2011 / Published online: 26 July 2011
Barcoding diatoms: evaluation of the V4 subregion on the 18S rRNA gene, including new primers and protocolsDownload PDFAbstract
Diatoms are present in all types of water bodies and their species diversity is influenced greatly by environmental conditions. This means that diatom occurrence and abundances are suitable indicators of water quality. Furthermore, continuous screening of algal biodiversity can provide information about diversity changes in ecosystems. Thus, diatoms represent a desirable group for which to develop an easy to use, quick, efficient, and standardised organism identification tool to serve routine water quality assessments. Because conventional morphological identification of diatoms demands specialised in-depth knowledge, we have established standard laboratory procedures for DNA barcoding in diatoms. We (1) identified a short segment (about 400 bp) of the SSU (18S) rRNA gene which is applicable for the identification of diatom taxa, and (2) elaborated a routine protocol including standard primers for this group of microalgae. To test the universality of the primer binding sites and the discriminatory power of the proposed barcode region, 123 taxa, representing limnic diatom diversity, were included in the study and identified at species level. The effectiveness of the barcode was also scrutinised within a closely related species group, namely the Sellaphora pupula taxon complex and relatives.
Received: 22 October 2010 / Accepted: 01 March 2011 / Published online: 17 March 2011
Higher-level metazoan relationships: recent progress and remaining questionsDownload PDFAbstract
Metazoa comprises 35–40 phyla that include some 1.3 million described species. Phylogenetic analyses of metazoan interrelationships have progressed in the past two decades from those based on morphology and/or targeted-gene approaches using single and then multiple loci to the more recent phylogenomic approaches that use hundreds or thousands of genes from genome and transcriptome sequencing projects. A stable core of the tree for bilaterian animals is now at hand, and instability and conflict are becoming restricted to a key set of important but contentious relationships. Acoelomorph flatworms (Acoela + Nemertodermatida) and Xenoturbella are sister groups. The position of this clade remains controversial, with different analyses supporting either a sister-group relation to other bilaterians (=Nephrozoa, composed of Protostomia and Deuterostomia) or membership in Deuterostomia. The main clades of deuterostomes (Ambulacraria and Chordata) and protostomes (Ecdysozoa and Spiralia) are recovered in numerous analyses based on varied molecular samples, and also receive anatomical and developmental support. Outstanding issues in protostome phylogenetics are the position of Chaetognatha within the protostome clade, and the monophyly of a group of spiralians collectively named Platyzoa. In contrast to the broad consensus over key questions in bilaterian phylogeny, the relationships of the five main metazoan lineages—Porifera, Ctenophora, Placozoa, Cnidaria and Bilateria—remain subject to conflicting topologies according to different taxonomic samples and analytical approaches. Whether deep bilaterian divergences such as the split between protostome and deuterostome clades date to the Cryogenian or Ediacaran (and, thus, the extent to which the pre-Cambrian fossil record is incomplete) is sensitive to dating methodology.
Received: 14 January 2011 / Accepted: 05 May 2011 / Published online: 18 May 2011
Species delimitations – not ‘only descriptive’Download PDFAbstract
Species descriptions as well as all other kinds of species delimitations within revisionary work are not ‘only descriptive’, as is often stated, but include several genuinely scientific, i.e. potentially falsifiable hypotheses: (1) The specimens under study represent a new or so far incorrectly defined species; (2) the phylogenetic position of the newly defined species; (3) descriptive terms, which are themselves hypotheses of homology (orthology) and/or function, regardless of whether they are of phenotypic or genotypic nature. Accordingly, species delimitations are genuine scientific hypotheses and thus should be cited in the same way as regularly done with all other previous scientific hypotheses on which a paper is based.
Received: 21 May 2010 / Accepted: 23 January 2011 / Published online: 06 February 2011
Cryptic, adaptive radiation of endoparasitic snails: sibling species of Leptoconchus (Gastropoda: Coralliophilidae) in coralsDownload PDFAbstract
Coral reefs are renowned as complex ecosystems with an extremely large biodiversity. Parasite-host relationships contribute substantially to this, but are poorly known. We describe the results of a study in which approximately 60,000 corals were searched for parasitic Leptoconchus snails (Gastropoda: Coralliophilidae) in Indo-West Pacific waters of Egypt, the Maldives, Thailand, Palau and Indonesia. We discovered an adaptive radiation of 14 snail species, each of which lives in species-specific association with one or more of 24 mushroom coral species. The 14 snail species are described as new to science under the names Leptoconchus inactiniformis sp. nov., L. inalbechi sp. nov., L. incrassa sp. nov., L. incycloseris sp. nov., L. infungites sp. nov., L. ingrandifungi sp. nov., L. ingranulosa sp. nov., L. inlimax sp. nov., L. inpileus sp. nov., L. inpleuractis sp. nov., L. inscruposa sp. nov., L. inscutaria sp. nov., L. intalpina sp. nov., and L. massini sp. nov. Their separation is based on indisputable molecular differences, whereas the rudimentary shell characters or impoverished anatomical details do not allow identification. The coral hosts also serve to distinguish the snail species, as none of the former was found to contain more than one of the latter. The complexity of coral reefs is still underrated, as is shown here by the application of DNA taxonomy as an indispensable approach to unravel cryptic radiations, which must be known in order to understand the functioning of the ecosystem.
Received: 14 April 2011 / Accepted: 22 August 2011 / Published online: 09 September 2011
A phylogeographic framework for the conservation of Saharan and Arabian Dorcas gazelles (Artiodactyla: Bovidae)Download PDFAbstract
Many species of gazelles (Gazella spp.) are nowadays threatened by hunting, poaching, habitat loss and habitat deterioration. Conservation efforts for this group not only face the problem of maintaining remnant populations, but often natural populations have been extirpated from the wild. In some cases, though, captive breeding programs exist that might provide a valuable source for future reintroductions. A major problem in this context is that phylogeographic relationships among different (potentially locally adapted) populations, and even basic phylogenetic relationships between species, are poorly understood, thus hampering the assignment of management units, breeding groups or stocks for reintroduction projects. Our present study focused on Dorcas gazelles (G. dorcas and G. saudiya) from the species’ entire distribution range, with samples originating from western Saharan Africa into Saudi Arabia. In stark contrast to previous studies reporting on pronounced genetic structure in taxa such as Mountain gazelles (G. gazella), we detected low genetic diversity and no evidence for major phylogenetic lineages when analyzing two mitochondrial genetic markers. Using a coalescent approach we infer a steep population decline that started approximately 25,000 years before present and is still ongoing, which coincides with human activities in Saharan Africa. Our phylogenetic analyses, statistical parsimony network analysis and inferred colonization patterns shed doubt on the validity of various described subspecies of G. dorcas.
Received: 02 February 2011 / Accepted: 16 June 2011 / Published online: 24 June 2011
Microanatomy and evolution of the nanostructures responsible for iridescent coloration in Trogoniformes (Aves)Download PDFAbstract
One of the most outstanding features of the order Trogoniformes is the presence of iridescent plumage, which is widely distributed throughout the group except in the species of the Asian genus Harpactes. Previous studies indicated that the iridescence-producing nanostructures vary in form and array throughout the order. Thus, the present study aimed at reconstructing the evolutionary history of those nanostructures in a phylogenetic context. The results show some clear tendencies in the evolution of iridescence-producing nanostructures throughout the order.
Received: 07 July 2010 / Accepted: 09 November 2010 / Published online: 24 November 2010
Cryptic diversity of Plasmopara viticola (Oomycota, Peronosporaceae) in North AmericaDownload PDFAbstract
Plasmopara viticola is the causal agent of grapevine downy mildew and is among the most important diseases in viticulture. It originates from North America, where it coevolved with wild Vitis species. Beginning in the 1870s it turned into a global epidemic that has been causing severe yield losses. It is generally believed that a single species is causing downy mildew on a large variety of economically important cultivars. Here we report, based on one nuclear and two mitochondrial markers, that isolates from vineyards in the United States fall into three highly distinct phylogenetic lineages. One of these contains European strains and affects Vitis vinifera cultivars, while the other two lineages affect also other species of Vitis. The divergence between these lineages is high, and, judging from the genetic variation in other Plasmopara lineages, might reflect distinct species. Due to the potentially significant implications for quarantine regulations and resistance breeding, detailed studies will be necessary to clarify whether these genetically distinct lineages occur outside of North America or are still confined there.
Received: 28 January 2011 / Accepted: 28 January 2011 / Published online: 12 February 2011
Supporting species in ODE: explaining and citingDownload PDF
Received: 15 February 2011 / Accepted: 26 July 2011 / Published online: 03 September 2011
Modelling sympatric speciation by means of biologically plausible mechanistic processes as exemplified by threespine stickleback species pairsDownload PDFAbstract
We investigate the plausibility of sympatric speciation through a modelling study. We built up a series of models with increasing complexity while focussing on questioning the realism of model assumptions by checking them critically against a particular biological system, namely the sympatric benthic and limnetic species of threespine stickleback in British Columbia, Canada. These are morphologically adapted to their feeding habits: each performs better in its respective habitat than do hybrids with intermediate morphology. Ecological character displacement through disruptive selection and competition, and reinforcement through mating preferences may have caused their divergence. Our model assumptions include continuous morphological trait(s) instead of a dimorphic trait, and mating preferences based on the same trait(s) as selected for in food competition. Initially, morphology is intermediate. We apply disruptive selection against intermediates, frequency-dependent resource competition, and one of two alternative mating preference mechanisms. Firstly, preference is based on similarity where mating preference may result from “imprinting” on conspecifics encountered in their preferred foraging habitat. Here, speciation occurs easily—ecological hybrid inferiority is not necessary. Hybrid inferiority reinforces the stringency of assortative mating. Secondly, individual preferences exist for different trait values. Here, speciation occurs when linkage disequilibrium between trait and preference develops, and some hybrid inferiority is required. Finally, if the morphology subject to disruptive selection, frequency-dependent competition, and mate choice, is coded for by two loci, linkage disequilibrium between the two loci is required for speciation. Speciation and reinforcement of stringency of choosiness are possible in this case too, but rarely. Results demonstrate the contingency of speciation, with the same starting point not necessarily producing the same outcome. The study resulted in flagging issues where models often lack in biological realism and issues where more empirical studies could inform on whether assumptions are likely valid.
Received: 10 March 2011 / Accepted: 26 July 2011 / Published online: 13 August 2011
Multilocus population analysis of Gavia immer (Aves: Gaviidae) mtDNA reveals low genetic diversity and lack of differentiation across the species breeding rangeDownload PDFAbstract
We analyzed the patterns of nucleotide sequence variation at three mitochondrial DNA loci, the noncoding mitochondrial control region and two genes (cytochrome b and cytochrome oxidase I) of Gavia immer in the largest collection of wintering individuals from Southern Europe to date. The sample consisted of 33 birds, oiled during the 2002/2003 Prestige tanker spill and washed ashore on the Galician coast (NW Iberian Peninsula). The aims of the study were to investigate the levels of standing genetic variation in the species, and to identify the geographic origin of these wintering birds. To do this, all available sequences of these loci, mostly from North American specimens collected from both the Atlantic and Pacific coasts, were retrieved from GenBank and included in the analysis. Overall, only 14 genetic variants were detected in the nearly 2 Kb surveyed, which reflects very low levels of nucleotide site diversity in this species. Interestingly, all variants were found at very low frequencies, and there was no indication of any clear subdivision in the G. immer population. This genetic profile is consistent with G. immer being a single panmictic population of small effective population size as compared with other seabirds. These circumstances preclude identification of the breeding regions of these wintering birds relying solely on genetic data. In the light of these results, possible causes, and the genetic and ecological consequences, of this demographic scenario are discussed.
Received: 27 December 2010 / Accepted: 31 August 2011 / Published online: 25 September 2011
Another example of cryptic diversity in lichen-forming fungi: the new species Parmelia mayi (Ascomycota: Parmeliaceae)Download PDFAbstract
In the last decade, a number of cryptic species have been discovered in lichenized fungi, especially in species with a cosmopolitan or disjunctive distribution. Parmelia saxatilis is one of the most common and widely distributed species. Recent molecular studies have detected two species, P. ernstiae and P. serrana, within P. saxatilis s. lat., suggesting the existence of considerable genetic diversity that may not yet be expressed at the phenotypic level. Due to the complexity in the P. saxatilis s. lat. group, we used this as a model to study the species boundary and identify cryptic lineages. We used Phylogenetic (Bayes, ML and MP) and genetic distance approaches to analyze ITS and β-tubulin sequences. Our results confirm the existence of another cryptic lineage within P. saxatilis s. lat. This lineage is described herein as a new species, P. mayi. It forms an independent, strongly supported, monophyletic lineage, distantly related to the morphologically similar species P. ernstiae, P. saxatilis and P. serrana. Morphologically, it is indistinguishable from P. saxatilis but the new species is separated by molecular, bioclimatic, biogeographic and chemical characters. At present, P. mayi appears to have a restricted distribution in the northern Appalachian mountain territories of North America. It is found in climatic conditions ranging from hemiboreal and orotemperate to cryorotemperate ultrahyperhumid bioclimates.
Received: 14 June 2011 / Accepted: 06 September 2011 / Published online: 23 September 2011
Systematics of Cuscuta chinensis species complex (subgenus Grammica, Convolvulaceae): evidence for long-distance dispersal and one new speciesDownload PDFAbstract
Cuscuta chinensis species complex is a small clade from subgenus Grammica (Cuscuta, Convolvulaceae). Many species of this clade exhibit crest- or dome-like multicellular appendages with stomata on the midvein/carena of calyx lobes. Basic morphology, scanning electron microscopy, and DNA sequence data from the plastid trnL-F region and the nuclear internal transcribed spacer (ITS) were used to investigate the phylogenetic relationships within the group and test the species limits. Based on their morphological and molecular similarly, C. chinensis and C. applanata represent one single species, and the latter was retained as a variety of the former. While the clade is centered in the southern USA and Mexico, C. chinensis var. chinensis has a disjunct distribution in Australia and Asia, which is likely the result of relatively recent long-distance dispersal. Cuscuta alata from Mexico, previously considered synonymous to C. applanata, was found to be a distinct species based on both molecular and morphological evidence. Cuscuta potosina var. potosina and var. globifera segregate into two different subclades of the C. chinensis species complex. Because these two taxa are also different morphologically, var. globifera is described as a new species, C. azteca. Cuscuta campestris, an almost cosmopolitan weed species from another clade (“Clade B”; “C. pentagona complex”), is commonly misidentified in Asia as C. chinensis, which raises questions about the identity of the Cuscuta plants used in widely commercialized medicinal herbal mixtures. A taxonomic treatment with an identification key, descriptions, and illustrations is provided.
Received: 04 June 2010 / Accepted: 10 January 2011 / Published online: 23 February 2011
Flowering phenology of co-occurring Asteraceae: a matter of climate, ecological interactions, plant attributes or of evolutionary relationships among species?Download PDFAbstract
We analyzed the flowering phenodynamics of 43 Asteraceae species co-occurring in natural populations of Chaco Serrano forests in central Argentina. We explored the potential influence of factors such as photoperiod and climate (variations in temperature, rainfall, and frost), animal-plant interactions (richness of floral visitors, frequency of visits), some plant attributes (plant growth form, seed dispersal mechanism), and evolutionary relationships among species on flowering phenodynamics. Cluster Analysis (CA) and Principal Component Analysis (PCA) were the multivariate statistical methods used to analyze emerging patterns associated with these co-occurring species. Null-model analyses were used to evaluate whether flowering times are aggregated, segregated, or random. Results showed that flowering phenology was significantly correlated with the seasonal variation in temperature, photoperiod, rainfall, and frost. The multivariate statistical methods separated all the species in three groups: 1) species with short flowering time, large plant floral display, high frequency of visits by a large number of species of floral visitors, anemochorous fruits, and shrubby growth form, with a tendency to a segregated flowering pattern; 2) species with long flowering time, small plant floral display, low frequency of visits by few insect species, anemochorous fruits, and herbaceous growth form; and 3) species with long flowering time, small plant floral display, intermediate values for frequency of visits and number of species of floral visitors, seed dispersal mechanisms other than anemochory, and herbaceous growth form. In addition, all but one species belonging to early-branching tribes (tribes phylogenetically close to the root of the Asteraceae tree) were grouped together and clustered in the same region of the two-dimensional PCA ordination. All species belonging to the late-branching tribes (Asteroideae subfamily tribes) included in group 1 were separated from the other Asteroideae species in the PCA. In conclusion, it seems that climatic factors restrict the phenological period of most species, and that plant attributes and taxonomic membership are strongly related to flowering phenodynamics in this group of Asteraceae studied.
Received: 03 January 2010 / Accepted: 05 April 2011 / Published online: 15 May 2011
Mixed colonies and hybridisation of Messor harvester ant species (Hymenoptera: Formicidae)Download PDFAbstract
The Mediterranean harvester ant species Messor minor, M. cf. wasmanni, and M. capitatus can co-occur in the same habitat. In Italian populations, we encountered colonies that contained workers from more than one species as identified via standard morphology, as well as colonies with workers that appeared to be morphologically intermediate between species. This unusual finding required further analysis. We analysed such colonies using microsatellites, mitochondrial DNA and refined morphometrics, and a simple inference key for the colony-level interpretation of data from the three sources combined. We infer that Messor minor and M. cf. wasmanni engage in bidirectional interspecific gene flow. Hybrids between these two species are inferred to produce fertile offspring, which would indicate that barriers to hybridisation do not exist or can be completely overcome. This is unexpected, given that they are non-sister species and broadly sympatric in nature. Our findings also indicate the possible occurrence of hybrid-hybrid crosses, a phenomenon rarely observed in ants. We cautiously interpret the data at hand as in support of the interspecific gene flow considerably shaping the genetic makeup of populations, raising the question about a potential adaptive value of this hybridisation. Messor capitatus mixes with hybrids of the other two species, but we found no indication of hybridisation involving this species. We discuss various hypotheses on the causations of colony mixing and hybridisation in the three Messor species at the proximate and ultimate level.
Received: 07 September 2010 / Accepted: 26 July 2011 / Published online: 02 August 2011
Assessment of hidden diversity of crinoids and their symbionts in the Bay of Nhatrang, VietnamDownload PDFAbstract
Crinoid associates represent an abundant and diverse, but poorly explored, component of the hidden biodiversity of coral-reef ecosystems. We studied data from 5 years of collecting in the Bay of Nhatrang (BN), Vietnam, to assess the diversity of crinoids and their symbionts, to compare it with other areas of the Indo-West Pacific, and to elucidate the extent to which the observed diversity of crinoids and their symbionts corresponds to their true diversity. In total, about 2,287 specimens of symbionts belonging to 70 species were found on 203 specimens of crinoids belonging to 33 species. Among the crinoids, the most numerous species were Himerometra robustipinna (36 specimens) and Cenometra bella (29 specimens), among the symbionts the polychaete Paradyte crinoidicola (c. 850 specimens) and the galatheid crustacean Allogalathea elegans (180 specimens). Species accumulation curves suggest that we have sampled most of the crinoid diversity in the BN, whereas the diversity of their symbionts remained undersampled. Estimated species richness of crinoids was higher than previously observed richness, and varied from 39 (estimated by bootstrap) to 46 (jackknife 2). Estimated species richness of symbionts was higher than observed richness, and varied from 71 (bootstrap) to 93 (jackknife 2). We suggest a slight increase in the number of crinoid species to result from more detailed studies of nocturnal species, and an increase in the number of symbiotic species when studies of nocturnal crinoid associates and sibling species among decapods are included. Our study revealed a rather rich crinoid fauna in the bay compared to other areas of the Indo-West Pacific, and the highest species richness of crinoid associates known from anywhere in the World Ocean.
Received: 01 November 2010 / Accepted: 28 April 2011 / Published online: 19 May 2011
Distribution and diversity of the Opheliidae (Annelida, Polychaeta) on the continental shelf and slope of Iceland, with a review of the genus Ophelina in northeast Atlantic waters and description of two new speciesDownload PDFAbstract
The diversity, taxonomy and distribution of the Opheliidae (Annelida: Polychaeta) in Icelandic waters is reviewed based on material collected during the BIOICE project. Nine opheliid species are recorded from Iceland; of these, three were previously reported in the area (Ophelia limacina, Ophelina cylindricaudata and O. acuminata), four are new for Icelandic waters (Ammotrypanella cf. arctica, Ophelina abranchiata, O. helgolandica and Tachytrypane jeffreisii), and two are new to science. Ophelina basicirra sp. nov. is distinguished by having a narrow anal tube with one short proximal anal cirrus in ventral position. Ophelina bowitzi sp. nov. is characterized by the small size of its anterior branchiae, which become larger in the middle and posterior body regions, and by an upwardly bent anal tube that is wide at the base and narrowing distally. The genera Euzonus, Armandia and Polyophthalmus are not represented in the BIOICE samples. The distribution of each species off Iceland is presented; one species is restricted to shallow waters of northwestern fjords, three species are found south of the GIF Ridge, and five species are circumicelandic. Several body characters with taxonomic relevance in some species are reviewed based on SEM images. Furthermore, as a first step towards a future revision of the genus Ophelina Örsted 1843 in North Atlantic waters, the status of each species originally described or subsequently reported from the area is commented on, and a key to the currently valid species is presented. Ophelina longicephala Hartmann-Schröder, 1977, formerly a subspecies of O. delapidans (Kinberg, 1866), is raised to species status.
Received: 21 March 2011 / Accepted: 02 October 2011 / Published online: 20 October 2011
Phenotypical plasticity and homoplasy complicate species delimitation in the Cladonia gracilis group (Cladoniaceae, Ascomycota)Download PDFAbstract
Species delimitation in the Cladonia gracilis group has long been known to be difficult due to morphological variability of taxa. The present study addresses the circumscription of species within this group, examining a number of specimens of the currently accepted taxa Cladonia coniocraea, C. cornuta subsp. cornuta, C. cornuta subsp. groenlandica, C. ecmocyna subsp. ecmocyna, C. ecmocyna subsp. intermedia, C. gracilis subsp. gracilis, C. gracilis subsp. elongata, C. gracilis subsp. tenerrima, C. gracilis subsp. turbinata, C. gracilis subsp. vulnerata, C. macroceras, C. maxima, and C. ochrochlora using genealogical concordance phylogenetic species recognition. We employed maximum parsimony, maximum likelihood and Bayesian methods of phylogenetic reconstructions based on DNA sequences of ITS rDNA, IGS rDNA, RPB2 and partially EF1-α regions. Our results indicate that the C. gracilis group is monophyletic but that most currently accepted taxa do not form monophyletic groups, with the exception of C. ecmocyna and C. cornuta subsp. cornuta. Different tests suggest that incomplete lineage sorting and sporadic recombination events are responsible for a phylogeny that largely lacks support. Our data also strongly suggest that C. coniocraea, C. cornuta subsp. groenlandica, and C. ochrochlora are conspecific, with C. coniocraea being the oldest available name. The morphological characters in the group are shown to be highly homoplasious, causing, in tandem with phenotypical plasticity of the taxa, the difficulties in delimiting species in the C. gracilis group.
Received: 20 December 2010 / Accepted: 22 August 2011 / Published online: 04 September 2011
Interspecific shape divergence in Aphodiini dung beetles: the case of Amidorus obscurus and A. immaturus (Coleoptera: Scarabaeoidea)Download PDFAbstract
The dung beetles Amidorus obscurus and A. immaturus are nearly indistinguishable, being characterized by a marked constancy in external morphological traits and little sexual dimorphism in adults. We studied two syntopic populations from the Italian Alps by means of geometric morphometric analyses. To identify possible undetected shape differences between species, we focused on the head, pronotum and scutellum (three external traits) and the epipharynx. Results indicate that the external traits are rather similar in the two species, whereas the epipharynx is clearly different. Interspecific differences in the aedeagus were also taken into account; these are noteworthy because parameres of A. immaturus differ in shape and are at least three times longer than those of A. obscurus. If it is assumed that the diversification of the two species took place during the quaternary ice age, A. immaturus would have evolved these marked differences rather quickly, in keeping with the hypothesis of rapid genital evolution. In an ontogenetic trajectory framework, we also considered the morphology of larvae. Interspecific divergence in the shape of the epipharynx is already evident at the preimaginal stage, whereas that of the genital disc is not. Accordingly, we hypothesise that the feeding and reproductive traits of these two species diverged morphologically when they become functional. Finally, by considering recent advances in ecological and evolutionary knowledge of dung beetles, the pattern of relative constancy in external morphology exhibited by the tribe Aphodiini, and that of great morphological diversification displayed by Onthophagini, were compared, and hypotheses about the origins of these differences discussed.
Received: 15 September 2010 / Accepted: 10 February 2011 / Published online: 24 February 2011
Comparative phylogeography of the centipedes Cryptops pictus and C. niuensis (Chilopoda) in New Caledonia, Fiji and VanuatuDownload PDFAbstract
The South Pacific is a biodiverse region of extreme evolutionary importance because it harbors ancient lineages and recent radiations. However, few population-level studies of genetic variation have been conducted in the land masses of this region. Likewise, the number of population-level studies using myriapods as models is extremely small. In this article, we compare the genetic structure of two species of centipedes in the genus Cryptops endemic to the South Pacific, one from a continental island, the other from oceanic islands. The level of genetic diversity and structure in C. pictus, a species endemic to New Caledonia, is much higher than in C. niuensis in Fiji and Vanuatu, despite the fact that C. niuensis is spread across two different archipelagos and several islands. The most likely explanation is the relatively young age of the remnants of the Vitiaz Arc (Fiji and Vanuatu) compared to New Caledonia. Using the emergence of Fiji-Vanuatu as a calibration point, C. pictus is estimated to have diverged by 23.4 Mya (upper 95% confidence interval) with a mean estimate of 11.7 Mya versus the 9.7 Mya of C. niuensis. Considering the absence of shared sequences between specimens from different sampling sites and the high genetic structuring within populations, C. pictus appears to be an ideal candidate to assess historical processes at a micro-evolutionary scale in New Caledonia.
Received: 24 December 2010 / Accepted: 26 July 2011 / Published online: 13 August 2011
New information on the evolution of mating behaviour in Sepsidae (Diptera) and the cost of male copulations in Saltella sphondylii
Here we describe the hitherto unknown details of the highly unusual mating behaviour of Saltella sphondylii—a widely cited model for male longevity costs caused by multiple copulations. When compared to the known mating behaviour of 28 sepsid species, we find five unique behavioural elements based on frame-by-frame analyses of video-recordings. These new behaviours are documented with video clips. We suggest that the male longevity costs could be due to copulation bouts that involve multiple insertions of a comparatively membranous phallus into the female. We compare the phallus of the Saltella sphondylii to those from three other species (Themira putris, Parapaleosepsis plebeia, Sepsis punctum).
Received: 05 January 2011 / Accepted: 31 August 2011 / Published online: 21 September 2011
New insights into the phylogeny and taxonomy of Chinese species of Gagea (Liliaceae)—speciation through hybridizationDownload PDFAbstract
A new region of speciation for the genus Gagea (Liliaceae) was investigated (Bogda-Shan and Urumqi; northwestern Xinjiang, China). Two species were recorded as new for the region (G. rufidula, G. davlianidzeae); three species are described as new to science (G. angelae, G. jensii and G. huochengensis). The description of G. nigra is emendated. Sequence data (cpDNA: trnL-trnF IGS+psbA-trnH IGS, nrDNA: ITS), including representatives of all Gagea sections, were used to compare the new species with closely related taxa. A nuclear single copy gene region (pCOS At103) was analysed for representatives of the Sects. Minimae and Gagea. Network analysis of cpDNA and nDNA indicates hybridization and recent speciation in Xinjiang. ITS and pCOS At103 sequences reveal gene flow between G. davlianidzeae and G. nigra. A cpDNA haplotype network constructed from representatives of Sect. Gagea was highly informative phylogenetically. Gagea angelae and G. huochengensis, sharing gene flow, are related closely to a basal clade represented by G. ancestralis, G. xiphoidea and G. capusii, which may include the putative progenitor of all other taxa of the large Eurasian Sect. Gagea. Whereas speciation in Sect. Minimae seems to be driven mainly by hybridization, speciation in the Sect. Gagea may be influenced by both hybridization and geographical separation. We confirm the monophyly of Sects. Bulbiferae and Minimae.