Phylogenetics of scutigeromorph centipedes (Myriapoda: Chilopoda) with implications for species delimitation and historical biogeography of the Australian and New Caledonian faunas

Phylogeny of the centipede order Scutigeromorpha has received recent attention from combined analyses of molecular and morphological data. Denser generic sampling, an additional marker (12S rRNA), and multiple specimens for selected species are used to explore phylogeny, biogeography and taxonomy of this charismatic group of centipedes. Among 55 specimens/27 species analysed for six genes are the first molecular data for the genera Dendrothereua , Pilbarascutigera , and Tachythereua , and previously unsampled species of Scutigerinae from Madagascar. Sampling density is especially increased for Thereuoneminae from Australia and New Caledonia. At the base of Scutigeromorpha, the split of Pselliodidae from Scutigerinidae + Scutigeridae is favoured by the optimal parameter set in combined analyses, but most suboptimal parameter sets instead unite pselliodids and scutigerinids. Dendrothereua is re-established for a Neotropical clade that variably resolves as sister to Tachythereua or separate from Scutigerinae, grouped with Pselliodidae and Scutigerinidae. As traditionally diagnosed, the genera that comprise most of Australian and New Caledonian diversity, Allothereua and Parascutigera , are mutually polyphyletic, though they unite as a well supported clade, sister to or including the Western Australian Pilbarascutigera . The main biogeographical signal within the Allothereua / Parascutigera clade is Western Australia as sister area to eastern Australia/New Caledonia, within which New Caledonian " Parascutigera " has a single origin under optimal parameter sets. Genetic variation within scutigeromorph species is appraised using samples of Scutigera coleoptrata throughout its native distribution plus presumed synanthropic records, and from the Allothereua/Parascutigera clade. Variation between six alleged narrow-range endemic species of Parascutigera in north Queensland is consistent with a single species.     

The peristomatic structures of Lithobiomorpha (Myriapoda, Chilopoda): comparative morphology and phylogenetic significance

A comparative survey of the epipharynx and hypopharynx of lithobiomorph centipedes by light and scanning electron microscopy examines 18 species that sample the major groups of both families, the Lithobiidae and Henicopidae. Cladistic analysis of 11 characters of the peristomatic structures together with 29 additional morphological characters serves as a basis for interpreting the evolution of the lithobiomorph peristomatic structures. Scutigeromorpha is used for outgroup comparison in the framework of a homology scheme for the basic components of the epi- and hypopharynx. Compared to other chilopods, the monophyly of Lithobiomorpha is supported by a row of distinctive bottle-shaped gland openings at the border between the labral and clypeal parts of the epipharynx, as well as by a distinctive shape of the hypopharynx. Paired rows of elongate spines on the clypeal part of the epipharynx are an apomorphic character of Lithobiidae. The transformation of these spine rows into a few groups of branching spines is characteristic for the Monotarsobius group sensu Verhoeff. Similar groups of branching clypeal spines characterize the Anopsobiinae within Henicopidae, whereas Henicopinae possess a dense cluster of short, simple spines instead. The recently described genus Dzhungaria is resolved closer to Henicopinae than to Anopsobiinae, a hypothesis supported by a field of grooves on the medial labral part of the epipharynx. Monophyly of Henicopidae does not receive unique support from the peristomatic structures although two homoplastic characters contribute to this node; among these, the reduction of a median spine field between clypeal and labral parts of the epipharynx to a narrow transverse band also supports a close relationship between the Ezembius group and Hessebius within Lithobiidae. An Ezembius+Hessebius clade is additionally supported by the absence of a transverse bulge between the clypeal and labral parts of the epipharynx, a character otherwise present in all lithobiomorph species studied so far. Lithobius is resolved as polyphyletic, with different species being most closely related to such genera as Australobius, Hessebius and Pleurolithobius.     

Phylogeny of scolopendromorph centipedes (Chilopoda): morphological analysis featuring characters from the peristomatic area

Alternative schemes for the higher‐level systematics of the centipede order Scolopendromorpha have been established from characters of trunk segmentation, including the segmental position of spiracles, and the presence or absence of eyes. A comparative survey of the preoral chamber by light and scanning electron microscopy contributes 16 new characters of the epipharynx and hypopharynx, sampled from 26 species that represent 20 genera. These new data together with 49 additional morphological characters permit cladistic analysis of the major scolopendromorph groups. The shortest cladograms resolve blind Scolopendromorpha as a basal grade within which a clade now classified as Plutoniuminae + Scolopocryptopidae (supported by unreversed characters from the preoral chamber) is sister to the remaining scolopendromorphs. A unique row of bullet‐shaped sensilla between the labral and clypeal parts of the epipharynx provides a new autapomorphy of the Scolopendromorpha. Either 21 or 23 trunk segments optimize at the base of the Scolopendromorpha but in either case homoplasy is forced on the cladogram. New characters from the epipharynx give additional support for the monophyly of several traditional groupings, including Cryptopinae, Scolopendridae, Otostigmini, and Scolopendrini, and a basal resolution of Asanadini within Scolopendridae. Of the two competing hypotheses for the position of the enigmatic Mediterranean Plutonium zwierleini—being either sister to the cryptopid Theatops or sister to all other Scolopendromorpha—the former hypothesis is strongly supported; spiracles on all trunk segments in Plutonium are homoplastic with the state in Geophilomorpha. Observations on feeding behaviour are needed to illuminate convergence in characters of the epipharynx and mandible in Edentistoma (Otostigminae) and Campylostigmus (Scolopendrini). © The Willi Hennig Society 2008.     

Phylogenetic analysis of Geotrupidae (Coleoptera, Scarabaeoidea) based on larvae

Abstract. Thirty‐eight characters derived from the larvae of Geotrupidae (Scarabaeoidea, Coleoptera) were analysed using parsimony and Bayesian inference. Trees were rooted with two Trogidae species and one species of Pleocomidae as outgroups. The monophyly of Geotrupidae (including Bolboceratinae) is supported by four autapomorphies: abdominal segments 3–7 with two dorsal annulets, chaetoparia and acanthoparia of the epipharynx not prominent, glossa and hypopharynx fused and without sclerome, trochanter and femur without fossorial setae. Bolboceratinae showed notable differences with Pleocomidae, being more related to Geotrupinae than to other groups. Odonteus species (Bolboceratinae s.str.) appear to constitute the closest sister group to Geotrupinae. Polyphyly of Bolboceratinae is implied by the following apomorphic characters observed in the ‘Odonteus lineage’: anterior and posterior epitormae of epipharynx developed, tormae of epipharynx fused, oncyli of hypopharynx developed, tarsal claws reduced or absent, plectrum and pars stridens of legs well developed and apex of antennal segment 2 with a unique sensorium. A ‘Bolbelasmus lineage’ is supported by the autapomorphic presence of various sensoria on the apex of the antennal segment, and the subtriangular labrum (except Eucanthus). This group constituted by Bolbelasmus, Bolbocerosoma and Eucanthus is the first evidence for a close relationship among genera, but more characters should be analysed to test the support for the clade. A preliminary classification at tribe level of Geotrupinae is suggested as follows: Chromogeotrupini (type genus Chromogeotrupes), Lethrini (type genus Lethrus), Taurocerastini (type genus Taurocerastes) and Geotrupini (type genus Geotrupes). Some ecological facts of Geotrupidae evolution could also be explained by the present results, such as those related to diet and nesting behaviour. Both coprophagy and male–female co‐operation in nesting appear as derived traits.     

New probability matrices for identification of Streptomyces

The character state data obtained for clusters defined in a previous phenetic classification were used to construct two probabilistic matrices for Streptomyces species. These superseded an original published identification matrix by exclusion of other genera and the inclusion of more Streptomyces species. Separate matrices were constructed for major and minor clusters. The minimum number of diagnostic characters for each matrix was selected by computer programs for determination of character separation indices (CHARSEP) and a selection of group diagnostic properties (DIACHAR). The resulting matrices consisted of 26 phena x 50 characters (major clusters) and 28 phena x 39 characters (minor clusters). Cluster overlap (OVERMAT program) was small in both matrices. Identification scores were used to evaluate both matrices. The theoretically best scores for the most typical example of each cluster (MOSTTYP program) were all satisfactory. Input of test data for randomly selected cluster representatives resulted in correct identification with high scores. The major cluster matrix was shown to be practically sound by its application to 35 unknown soil isolates, 77% of which were clearly identified. The minor cluster matrix provides tentative probabilistic identifications as the small number of strains in each cluster reduces its ability to withstand test variation. A diagnostic table for single-membered clusters, constructed using the CHARSEP and DIACHAR programs, was also produced.     

Spermiogenesis and spermatozoal ultrastructure in Trichomycteridae (Teleostei: Ostariophysi: Siluriformes)

Spadella, M.A., Oliveira, C. and Quagio‐Grassiotto, I. 2009. Spermiogenesis and spermatozoal ultrastructure in Trichomycteridae (Teleostei: Ostariophysi: Siluriformes). —Acta Zoologica (Stockholm) 91 : 373–389. Siluriformes comprises the most diverse and widely distributed ostariophysan group, a fish assemblage that includes about three quarters of the freshwater fish of the world. In this study, the ultrastructural characterization of spermiogenesis and spermatozoa in specimens of Copionodontinae (the sister group to all other trichomycterids), Trichomycterinae (a derived trichomycterid group), and Ituglanis (a genus not assigned to any trichomycterid subfamily) is presented. The comparative analyses of the data show that trichomycterid species share six of seven analyzed spermiogenesis characters, reinforcing the monophyly of the group. Analyses of trichomycterid sperm ultrastructure showed that the species studied share the same character states for nine of seventeen characters analyzed. Copionodon orthiocarinatus and Ituglanis amazonicus each share more ultrastructural characters with species of Trichomycterus than with one another. Regarding the families of Loricarioidea, the species of Trichomycteridae share more characters of spermatogenesis, spermiogenesis, and sperm with representatives of the families Callichthyidae, Loricariidae, and Scoloplacidae than with Nematogenyidae, its hypothesized sister group. With the exception of the family Nematogenyidae, the character similarities observed reinforce the monophyly of the superfamily Loricarioidea.     

Epipharynx shape as a tool to reveal differentiation patterns between insect sister species: insights from Onthophagus taurus and O. illyricus (Insecta: Coleoptera: Scarabaeidae)

We evaluated the potential of the adult epipharynx to reveal interspecific differentiation patterns in closely related Onthophagus species. Although easy to analyse, this structure has received little attention in Scarabaeidae taxonomy, probably because a qualitative inspection of its shape often does not yield differences between congeneric species. The polyphenic sister species Onthophagus taurus Schreber, 1759 and O. illyricus Scopoli, 1763 were chosen as a case study. They are extremely similar, to the extent that in some cases they cannot be identified unambiguously without the help of biomolecular analysis. In this study, a combination of linear measurements and a landmark-based approach was employed to quantify inter- and intraspecific shape variation in the epipharynx of specimens sampled at the same study site. Our results showed that the epipharynx is a monomorphic structure: its shape does not vary as a function of sex or male phenotype. In males, epipharynx shape does not change with head shape or horn length. The close proximity of the epipharynx to the horns and the synchronous developmental patterns of these two structures suggest that a developmental trade-off may act between them. Despite these predisposing conditions, however, our results suggest that epipharynx size is not subject to costs associated with horn development, and that the trait is highly canalised. Surprisingly, when using geometric morphometrics the epipharynx appears to be a better tool than genitalia for discriminating between the two sister species.     

The source of chilopod sensory information: External structure and distribution of antennal sensilla in Scutigera coleoptrata (chilopoda,Scutigeromorpha)

The investigation of the antennae of Scutigera coleoptrata (Linnaeus, 1758) by scanning electron microscopy (SEM) revealed the presence of five types of sensilla: sensilla trichodea, beak‐like sensilla, cone‐shaped sensilla brachyconica on the terminal article, sensory cones at the antennal nodes, and the shaft organ. Alongside the presence and absence of antennal sensillar types, three unique characters were found in the Scutigeromorpha: the presence of long antennae with nodes bearing sensory cones, the presence of a bipartite shaft including the shaft organ, and the presence of beak‐like sensilla. Neuroanatomical data showed that the animals' brains are equipped with well‐developed primary olfactory and mechanosensory centers, suggesting that the antennae must be equipped with specialized sensilla to perceive chemosensory and mechanosensory cues. With the evidence provided in this article for the Scutigeromorpha, SEM data are available at last on the antennal sensilla for all five chilopod taxa, allowing a comparative discussion of antennal morphology in Chilopoda. J. Morphol., 2011. © 2011Wiley‐Liss, Inc.     

Phylogeny of the water strider genus Rheumatobates (Heteroptera: Gerridae)

The genus Rheumatobates comprises thirty‐seven species and subspecies of New World water striders belonging to subfamily Rhagadotarsinae. Among species, males vary dramatically in the degree and nature of modifications of the antennae, three pairs of legs and abdominal and genital segments. Characters describing this modification have traditionally been used to differentiate and group species. The general assumption has been that modified species belong to one group and unmodified species to another. These two ‘species groups’ are subdivided into ‘subgroups’, but little effort has been made to resolve relationships among them. We conduct the first numerical cladistic analysis of Rheumatobates using a data set comprised of 102 characters, primarily describing modification of male external morphology. To address concerns about the inclusion of characters to be optimized on the phylogeny, characters describing modification of antennae and hind legs were included and then excluded in separate analyses. A preferred phylogeny was chosen from the four equally parsimonious cladograms found after successive reweighting of characters. There was good resolution at all levels of the phylogeny. Most of the major clades and terminal relationships were moderately to strongly supported, whereas the basal relationships were less well supported. The general assumption that unmodified and modified species form two monophyletic groups was not supported. However, traditionally recognized ‘subgroups’ within the modified species group were largely upheld. The analysis also suggested several major clades and relationships among these clades that were not previously recognized. The exclusion of characters describing modification of antennae and hind legs did not change the resolved major clades of the reconstructed phylogeny.     

SEXUAL AND GENETIC ISOLATION IN THE COSMOPOLITAN ALGAL SPECIES PANDORINA MORUM

In an effort to analyze the nature of a taxonomic species in the microalgae, the major biological characters of various isolates of Pandorina morum have been studied. Seventy heterothallic clones from 31 collecting sites on three continents were found to represent 20 reproductively isolated groups, based on their ability to form zygotes when paired in all possible combinations. Successful germination of the zygotes and demonstrated fertility of their products suggest that each reproductively isolated group represents a syngen—a group of organisms sharing a common gene pool. A further indication of the close relationship of members of the same syngen is that its representatives all share a common chromosome number, time of division, and zygote distribution pattern, characters which vary between syngens. The known range of 18 of the syngens is less than 500 km. The other two syngens may have a world-wide distribution; they both have a haploid chromosome number of 5. Crosses between geographically isolated clones in these two syngens and one other give evidence of both pre- and postzygotic partial isolation within a syngen. Analysis of collections from two revisited sites demonstrated that representatives of a syngen can be recovered after 19 years have elapsed, and that a single pond may contain as many as four syngens. The results obtained for P. morum are compared with the information available on other microalgae with a similar breeding system, and the possible causes and consequences of the species structure are discussed.     

FINE STRUCTURE OF MISTLETOE POLLEN. IV. EURASIAN AND AUSTRALIAN VISCUM L. (VISCACEAE)

Fifteen Eurasian and Australian species of Viscum L. were examined by light, scanning, and transmission electron microscopy. Pollen characters divide the species into two groups, each correlated with differences in habit and inflorescence structure: Group I (12 spp.) characterized by psilate or slightly sculptured exines and a non-uniform ektexine pattern and Group II (3 spp.) possessing highly sculptured (echinate, rodlet) surfaces and uniform ektexine patterns. Within each of the groups, pollen characters divide the species into several subgroups. Among Group I, species V. nepalense, V. heyneanum and V. ovalifolium are particularly close. The Group I species, V. trilobatum, is placed in its own subgroup primarily because of its uniform ektexine pattern—a unique feature among Asian and Australian Viscum. Of the three Group II species, V. album and V. alniformosanae are palynologically almost indistinguishable. Pollen of the Group II V. cruciatum, though exomorphologically similar to V. album, is closest ultrastructurally to the Indian V. trilobatum. Overall, the most common and probably basic pollen characters among the Eurasian and Australian species include: subprolate, rounded convex almost spherical shapes; tricolporate apertures, and non-uniform sculpturing and ektexine patterns. Oblate-spheroidal or prolate-spheroidal shapes, prominent sculpturing, and a uniform ektexine pattern are derived characters largely restricted to the Eurasian and Asian Group II species (V. album, V. alniformosanae, V. cruciatum).     

Population structure of arctic lamprey <Emphasis Type="Italic">Lethenteron camtschaticum</Emphasis> from the Kol River (Western Kamchatka)

Phenetic diversity is investigated and the taxonomic status of lampreys (Petromyzontidae) from the Kol basin (Western Kamchatka) is verified. Typically anadromous lamprey, anadromous lamprey forma praecox, resident lamprey, smolts, and larvae of lamprey are discovered and described. Their comparative analysis is made by standard morphometric characters. Differences between the forms by plastic characters depend on size and weight. No significant differences are found by major taxonomic characters between the forms of anadromous and resident lampreys which would indicate their taxonomic separation. Phenetic types of spawners are representatives of the population of one complexly structured species represented by life forms realizing different life history strategies (anadromous and resident), and belong to the species Arctic lamprey Lethenteron camtschaticum (Tilesius, 1811).     

Morphology of ctenostome bryozoans: 1. Arachnidium fibrosum

The morphology of ctenostome bryozoans remains little investigated with only few species having been subject to more detailed studies. From all the seven main different superfamilies, only few representatives have been studied. The superfamily Arachnidioidea has particularly been neglected concerning detailed morphological and histological details. So far, not a single analysis specifically studied a representative of the family Arachnidiidae. Arachnidium-like forms have, however, often been regarded as potential cheilostome ancestors, the most successful group of bryozoans to date. The lack of any morphological data on this family called for a detailed investigation of one of its representatives. Hence, we analysed the general morphology and histology of Arachnidium fibrosum. Most striking morphological features previously unrecognized are a cardiac constrictor, previously almost unknown in the family, a single pair of apertural muscles consisting of proximal parieto-diaphragmatic and distal parieto-vestibular muscles, six pairs of duplicature bands, a lophophoral anus and retractor muscles attaching to the foregut. Although comparative data are limited, there seem to be two distinct different clades of arachnidiid ctenostomes that are characterized by their aperture and details of gut morphology. Further analysis of additional arachnidioidean species are required to confirm this.     

绣球属(Hydrangea L.)及近缘属花粉形态的研究

为深入研究绣球属植物花粉形态的分类学价值和系统学意义,厘清绣球属与近缘属之间的系统发育关系,该文利用扫描电子显微镜(SEM,scanning electron microscope)对国产绣球属及其近缘属41种绣球花科(Hydrangeaceae)植物的花粉形态以及表面纹饰进行了观察。结果表明:绣球属及其近缘属的花粉为三孔沟;形状多数为长圆体形或近球体形;赤道面观为椭圆形或圆形;极面观多为圆形,少数为三角形或圆三角形。花粉外壁纹饰可分为网状和孔穴状。网眼内的三级纹饰可分为光滑和具颗粒状突起。根据花粉形状和外壁纹饰类型将上述物种划分为4个组,即花粉的形状为长圆体形,表面纹饰为孔穴纹饰;花粉的形状为长圆体形,表面纹饰为网状纹饰;花粉的形状为近球体形,表面纹饰为孔穴纹饰;花粉的形状为近球体形,表面纹饰为网状纹饰。以上可进一步细分为8个类型。上述表明花粉形态证据可为绣球属及其近缘属的属下分类和种间界定提供重要佐证;但结合前人的系统发育重建分析该属植物花粉形态的系统学意义相对有限,如花粉形态证据对于该属及其近缘种属系统发育树上大支的界定难以提供有力的证据。     

Studies on sexual compatibility betweenEctocarpus siliculosus (Phaeophyceae) from Chile and the Mediterranean Sea

Clonal isolates of the brown algaEctocarpus siliculosus (Ectocarpales) originating from Naples (Mediterranean Sea) and southern Chile were compared in laboratory culture studies. The two isolates showed distinctly different morphological characters, but very similar details of life history and sexual reproduction. Gametes are sexually compatible; hybrid zygotes are formed and sporophytes develop, which are fertile on the basis of mitotic spores. However, unilocular sporangia were abortive, indicating segregational sterility caused by chromosomal mismatch during meiosis. Although the biological species concept in a strict sense does not apply, and appreciable morphological variability exists in this cosmopolitan taxon, local populations are considered as representatives of the same species. Dedicated to Dr. Dr. h. c. Peter Kornmann on the occasion of his eightieth birthday.     

Micromorphological studies of the leaf epidermis of Iranian Cotoneaster Medik

In this study, micromorphological features of the leaf epidermal cells of 17 species of Iranian Cotoneaster were determined. The studied species were compared with each other and with phylogenetic relationships established by previous studies. Three populations of C. integerrimus and C. multiflorus were studied as representatives of C. subgen. Cotoneaster and Chaenopetalum, respectively. To evaluate quantitative and qualitative characters, multiple correspondence analysis (MCA) and factor analysis of mixed data (FAMD) were performed. Finally, relationships among the taxa were illustrated by hierarchical clustering analysis. Three stomatal types were identified, i.e. anomocytic, stephanocytic and actino‐stephanocytic. The wax and cuticle density was higher in species from semi‐moist habitats than in those from dry and semi‐dry habitats. The patterns formed by the anticlinal walls of the epidermal cells were sinuous, repand and straight‐curved. Interestingly, there was a significant relationship between the length of leaves, the density of the indumentum and the pattern formed by the anticlinal cell walls. The leaves of species with large leaves also have lower hair density and more curved anticlinal cell walls. It appears probable that climatic conditions affected the evolution of leaf micro‐morphological characters during the early diversification of the genus, but that these characters have subsequently been permanently fixed by phylogenetic constraints and thus appear diagnostic for extant species.     

Regional genetic variation in the major sperm protein genes of Onchocerca volvulus and Mansonella ozzardi (Nematoda: Filarioidea)

Onchocerca volvulus and Mansonella ozzardi are two human filarial parasites present in South and Central America. In the Brazilian Amazonia they are found in sympatry, and the lack of clear morphological diagnostic characters in the microfilariae hinders their identification. The major sperm protein (MSP) gene of both species has been sequenced and characterised to determine its potential as a molecular diagnostic character. The length of the MSP gene is different in each species, and this could be used to detect and differentiate them by running the polymerase chain reaction (PCR) product in an agarose gel. Two major gene groups were identified in O. volvulus with a genetic distance of 6% between them. In M. ozzardi only one major group of genes was observed. The high similarity between the protein amino acid sequence of both filarial species confirms that the MSP has been highly conserved through nematode evolution.     

On the evolutionary pathways of speciation in the genus Notholca

An attempt is undertaken to determine criteria and limits of taxonomic rank in the genus Notholca proceeding from the standpoint of level-values of the characters evolution. Level-values of characters were established using Vavilov's principle of homologic series of hereditary variability. As a result of taxonomic revision such terms as group of species, species and subspecies are recommended. Analysis of the scheme of relations between representatives of the genus and data on their ranges gives a clue to relations between phylogeny and geographic distribution of the group over the vast territory of the Asian continent which may have been its centre of speciation.