Received: 12 March 2009 / Accepted: 21 July 2009 / Published online: 12 March 2009
Labidocera boxshalli sp. nov., a new calanoid copepod (Crustacea; Pontellidae) from the Red SeaDownload PDFAbstract
A pontellid copepod, Labidocera boxshalli sp. nov., is described from the Egyptian coast of the northern Red Sea. This species is most readily distinguished from its congeners by the presence of a mid-dorsal process on the female genital double somite, the female fifth leg exopod terminating in two superimposed processes (the ventral of which is shorter), and by the elongated first exopodal segment of the male right fifth leg carrying a stout, blunt-tipped process and a small papilla laterally near the base of the thumb that bears one seta. The new species belongs to the L. detruncata species group, which is distributed mainly in the tropical/subtropical waters of the Indo-West Pacific.
Received: 31 July 2008 / Accepted: 06 May 2009 / Published online: 31 July 2008
Red- and yellow-footed tortoises, Chelonoidis carbonaria and C. denticulata (Reptilia: Testudines: Testudinidae), in South American savannahs and forests: do their phylogeographies reflect distinct habitats?Download PDFAbstract
Using sequence data of the mitochondrial cytochrome b gene, we investigated phylogeographic differentiation of the Amazonian tortoise species Chelonoidis carbonaria and C. denticulata. While C. carbonaria is generally restricted to savannah habitats and adjacent forests, C. denticulata is associated with wet tropical and subtropical forests. Our study suggests a correlation between distinct habitat preferences and phylogeography of the two species. In Maximum Parsimony, Maximum Likelihood and Bayesian analyses, haplotypes of C. carbonaria cluster in several distinct clades reflecting the species’ patchy distribution in savannah habitats. By contrast, haplotypes of C. denticulata are only weakly differentiated; a finding also confirmed by parsimony network analysis. This suggests that the contiguous Amazonian rainforest allows gene flow between populations of the forest-dwelling C. denticulata throughout the range, but significantly impedes gene flow in C. carbonaria. The phylogeographic structure and extant distribution pattern of C. carbonaria is supportive of former Amazonian rainforest fragmentation, enabling the dispersal of savannah species. Based on fossil calibration, we dated divergence times for the C. carbonaria clades using a relaxed molecular clock, resulting in average estimates ranging from 4.0–2.2 mya. This implies that the onset of rainforest fragmentation could predate the Pleistocene considerably. Furthermore, our findings call for further research on geographic and taxonomic variation in C. carbonaria and for a reassessment of the conservation status of the distinct genetic units.
Received: 09 October 2008 / Accepted: 14 May 2009 / Published online: 09 October 2008
Optimality of phylogenetic nomenclatural proceduresDownload PDFAbstract
Nomenclatures resulting from the application of various procedures are viewed as communication tools whose optimality can be compared. The traditional, node-based, branch-based, apomorphy-based, and cladotypic procedures are compared based on theoretical cases. The traditional procedure collects several major drawbacks: endings related to ranks are of low information content on taxa hierarchy; with respect to procedures using uninominal species names, in case of a partly unbalanced and/or partly unresolved phylogeny, the application of the procedure results into supernumerary names; a traditional taxon name is prone to be polysemic, depending upon someone’s opinion on the rank and composition of the taxon, and upon conflicting hypotheses on the phylogenetic position of name-bearing types. Alternative systems vary in merit. Names of apomorphy-defined taxa are prone to be polysemic due to possible ambiguity in the formulation of the defining character state. The cladotypic nomenclatural procedure is similar in that respect, but a set of rules allow ambiguity to be limited. The main issue of node- and branch-based procedures is that cases of synonymy cannot be settled if the inner phylogeny of taxa cannot be resolved. Cases of irresolvable synonymy can occur under apomorphy-based and cladotypic procedures, but the problem can be circumvented by the use of taxa whose defining character state is not subject to ambiguous mapping. Node-, branch- and apomorphy-based definitions as governed by the PhyloCode can produce nonsensical statements, but this problem can be fixed by the adjunction of falsifiable assumptions in use under the cladotypic procedure. Cladotypic definitions must involve a fourth assumption formulated as ‘cladotypes belong to different species’ (cladogenesis assumption). The present contribution suggests that the cladotypic procedure outperforms all other proposed procedures, producing an optimal formal lexicon useful for naming and communicating about species and taxa.
Received: 17 December 2009 / Accepted: 14 April 2010 / Published online: 17 December 2009
Two Pione species (Hadromerida, Clionaidae) from the Red Sea: a taxonomical challengeDownload PDFAbstract
Boring sponges of the genus Pione (Hadromerida, Clionaidae) are easily recognizable due to their spiculation. However, species identification is challenging, as the potentially diagnostic morphological character states of different species often overlap. For this reason, this group of species is frequently referred to as the ‘Pione vastifica complex’, after the most well-studied species of the genus. Boring-sponge samples were collected in the Red Sea and identified as P. cf. lampa and P. cf. vastifica, respectively. So far, these two species names have usually been considered as valid, although some authors suggested them to be synonymous. Morphological analyses were performed on spicules and micro-erosion patterns by means of both light and scanning electron microscopy. Two apparent morphotypes can be distinguished, mainly by the growth form, but statistical analysis does not support a clear separation in two species. In addition, a DNA barcoding approach using sequences of CO1 has not identified any nucleotide sequence differences. These data support the hypothesis that P. cf. lampa and P. cf. vastifica from the Red Sea are conspecific.
Received: 16 December 2008 / Accepted: 25 June 2009 / Published online: 16 December 2008
Phylogenetic relationships in the ‘Pinnatella’ clade of the moss family Neckeraceae (Bryophyta)Download PDFAbstract
The family Neckeraceae is composed of three distinct clades, of which two, i.e. the Neckera and Thamnobryum clades, are well defined. The third clade, consisting of species belonging to Caduciella, Curvicladium, Handeliobryum, Himantocladium, Homaliodendron, Hydrocryphaea, Neckera, Neckeropsis, Pinnatella, Shevockia and Taiwanobryum, is the focus of this study. Based on sequence data from the trnS-rps4-trnT-trnL-trnF plastid cluster and the rpl16 intron as well as from nuclear ITS1&2, the phylogenetic relationships of these genera are reconstructed. The nearest relatives of this clade are resolved shedding more light on the evolution of the family. The generic composition of the clade and its individual genera are discussed; polyphyly requires redefinition of Pinnatella, Neckeropsis and Homaliodendron. The positions of Touwia and Homalia within the family are addressed in an additional analysis based on more extensive sequence data, and the corresponding new combinations are made. Several further taxonomic changes are proposed, including Circulifolium gen. nov., comprising the former Homaliodendron exiguum and H. microdendron.
Received: 04 March 2009 / Accepted: 26 November 2009 / Published online: 04 March 2009
Morphology of the pronotal compound glands in Tritoma bipustulata (Coleoptera: Erotylidae)Download PDFAbstract
Members of the cucujiform family Erotylidae possess a whole arsenal of compound integumentary glands. Structural details of the glands of the pronotum of Tritoma bipustulata and Triplax scutellaris are provided for the first time. These glands, which open in the posterior and anterior pronotal corners, bear, upon a long, usually unbranched excretory duct, numerous identical gland units, each comprising a central cuticular canal surrounded by a proximal canal cell and a distal secretory cell. The canal cell forms a lateral appendix filled with a filamentous mass probably consisting of cuticle, and the cuticle inside the secretory cell is strongly spongiose—both structural features previously not known for compound glands of beetles. Additional data are provided for compound glands of the prosternal process and for simple (dermal) glands of the pronotum. A combined defense plus anti-microbial function of the compound glands is tentatively proposed.
Received: 01 December 2009 / Accepted: 16 March 2010 / Published online: 01 December 2009
Progress in erigonine spider phylogeny—the Savignia-group is not monophyletic (Araneae: Linyphiidae)Download PDFAbstract
We present the most inclusive study on the higher-level phylogeny of erigonine spiders, including about 30% of all erigonine genera. By expanding the previously most comprehensive analysis (Miller and Hormiga Cladistics 20:385–442, 2004) we tested the robustness of its results to the addition of closely related taxa, and also the monophyly of the Savignia-group defined by Millidge (Bulletin of the British Arachnological Society 4:1–60, 1977). The character matrix was expanded by adding 18 newly scored species in 15 genera, and also includes all species scored by other authors. This adds up to 98 species in 91 erigonine genera plus 13 outgroup taxa. The parsimony analysis led to eight fully resolved most parsimonious trees (L=1084). The topology concerning the taxa basal to the ‘distal erigonines’ remained unchanged, and the latter clade still shares 67% of all nodes with the original analysis. The Savignia-group is not monophyletic at genus level with respect to Saloca diceros and Alioranus pastoralis, and the same applies at species level in Diplocephalus and Erigonella. From the Savignia-group, Glyphesis servulus, Diplocephalus cristatus, Savignia frontata, and two representatives each of Erigonella, Dicymbium and Araeoncus combine to form a monophyletic clade.
Received: 02 October 2009 / Accepted: 16 January 2010 / Published online: 02 October 2009
Nomenclatural rules in zoology as a potential threat against natural history museumsDownload PDFAbstract
Natural history museums store millions of organisms from the whole world that are of great use to understand the evolution, structure and problems of biodiversity. One of their main functions is to act as repositories of so-called type specimens or onomatophores. These allow long-term universality and stability of biological nomenclature through providing an objective and permanent link between the world of language and the world of organisms. Threats currently exist against this function, in two directions at least. (1) Recent changes to the nomenclatural rules put the emphasis on ‘usage’ of nomina and challenge ‘priority’ as the basic principle of nomenclature. This entails a shift from specimens to concepts or tradition for the establishment of the valid nomina of taxa. Beside its encouraging taxonomists to work carelessly and hastily, this attitude weakens the significance and importance of those specimens in taxonomy, undermining their important flag function for the image, funding and even the mere existence of natural history museums. To counter this tendency, any validation of junior synonyms or homonyms to protect usage should be strictly limited to nomina in well-documented very widespread use, not only in specialized systematic publications but in the general scientific and non-scientific literature and in society as a whole. (2) For the same reason, nomenclatural systems that rely not on onomatophores but on verbal definitions of nomina should not be encouraged. It is crucial that the unique value of onomatophores be highlighted, and that the institutions which care for their long-term conservation and scientific managing be recognised and permanently provided with appropriate funding and staff. Many other disciplines of biology do or will benefit from such a support to museums.
Received: 11 May 2009 / Accepted: 14 October 2009 / Published online: 11 May 2009
Systematics of limbless scincid lizards from northern Madagascar: morphology, phylogenetic relationships and implications for classification (Squamata: Scincidae)Download PDFAbstract
We report on the rediscovery of two limbless scincid species, Paracontias rothschildi Mocquard, 1905 and Paracontias minimus (Mocquard, 1906), after more than a century. The two species were found in syntopy in sandy soils of Forêt d’Orangea, Antsiranana Province, northern Madagascar, which probably constitutes the respective type locality and confirms the species’ Malagasy origin. Both taxa are redescribed based on newly collected material, and compared to other Malagasy species. In addition, Paracontias fasika n. sp. is described from the same locality and habitat. We discuss the taxonomy and origin of all three species and provide preliminary data on their natural history. Molecular relationships among seven Paracontias species are compared to external morphological characters formerly used in skink systematics. Our results indicate that morphology in fossorial skinks is well suited to distinguish species, but is of rather limited value to elucidate phylogenetic relationships. Similarities between these skinks in external characters apparently are the result of convergent evolution due to parallel selective pressures.
Received: 02 February 2009 / Accepted: 19 August 2009 / Published online: 02 February 2009
Revision of Chilean bathyal chitons (Mollusca: Polyplacophora) associated with cold-seeps, including description of a new species of Leptochiton (Leptochitonidae)Download PDFAbstract
The chiton fauna of Chile comprises 41 species, most of which inhabit shallow waters. The present paper gives a summary of all 14 chiton species reported from Chilean deep (bathyal to abyssal) waters, including some records that might be considered as doubtful. Leptochiton laurae n. sp. is formally established; it was formerly misidentified as L. americanus Kaas & Van Belle, 1985, but differs in the shape of the tail valve, less coarse sculpturing, in the girdle elements and radula armature. Two additional new species, Leptochiton sp. and Placiphorella sp., are discussed. For Leptochiton medinae Plate, 1899, a lectotype is designated. Tripoplax balaenophila (Schwabe & Sellanes, 2004) n. comb. is transferred from Lepidozona Pilsbry, 1892, due to coarse sculpturing in the central areas and multi-slit insertion plates. Leptochiton belknapi Dall, 1878 and Tripoplax cowani Clark, 2008 are reported from the study region for the first time. The majority of the Chilean deep-water polyplacophorans are associated with hard substrates (authigenic carbonates) near methane seeps. The present report raises the global number of chiton species inhabiting chemosynthetic environments from 10 to 18, including some overlooked literature records from other regions.
Received: 13 December 2008 / Accepted: 21 July 2009 / Published online: 13 December 2008
Old museum samples and recent taxonomy: A taxonomic, biogeographic and conservation perspective of the Niphargus tatrensis species complex (Crustacea: Amphipoda)Download PDFAbstract
Natural history museum collections harbour valuable information on species. The usefulness of such data critically depends on the accurate identification of species, which has been challenged by introduction of molecular techniques into taxonomy. However, most collections may suffer from DNA degradation, due to age and/or improper preservation; hence the identification of specimens depends solely on morphological features. This study explores how and to what extent morphological data can help to solve ambiguous taxonomic cases based on selected species concepts and with the use of operational criteria in a species-hypothesis testing procedure. The studied taxon, the Niphargus tatrensis species complex, comprises freshwater subterranean amphipods, distributed across Central Europe, the taxonomic status of which was debated extensively between 1930 and 1960. Using the general species concept, character- and tree-based operational criteria reveal northern and southern diagnosable and exclusive lineages identified here as N. tatrensis Wrześniowski, 1888 and N. scopicauda sp. n., respectively. The remaining populations represent the non-exclusive N. aggtelekiensis Dudich, 1932, which occurs from the eastern Alps to Hungary. In the entire complex, altitudinal distribution is largely limited to areas above 400 m, where the mean annual temperature never exceeds 9°C. Seemingly well-defined distributional ranges of N. tatrensis and N. aggtelekiensis are fragmented in an ecological sense, which raises the question whether two of the three species recognised here actually consist of several unidentified taxa. Morphological similarity between the species, numerous polymorphic features, and the association with cool temperatures lead to a hypothesis in which fragmentation of the ancestral range occurred during post-Pleistocene climate warming, reducing gene flow across lowland populations due to niche conservatism of the ancestral species and/or to invasion of competitive species along the Danube and Drava rivers. The results are discussed regarding how old museum samples are conducive to more detailed molecular-taxonomic and conservation studies.
Received: 26 February 2010 / Accepted: 23 May 2010 / Published online: 26 February 2010
Wikipedia as an encyclopaedia of lifeDownload PDFAbstract
In a 2003 essay E. O. Wilson outlined his vision for an “encyclopaedia of life” comprising “an electronic page for each species of organism on Earth”, each page containing “the scientific name of the species, a pictorial or genomic presentation of the primary type specimen on which its name is based, and a summary of its diagnostic traits.” Although biodiversity informatics has generated numerous online resources, including some directly inspired by Wilson’s essay (e.g., iSpecies and EOL), we are still some way from the goal of having available online all relevant information about a species, such as its taxonomy, evolutionary history, genomics, morphology, ecology, and behaviour. While the biodiversity community has been developing a plethora of databases, some with overlapping goals and duplicated content, Wikipedia has been slowly growing to the point where it now has over 100,000 pages on biological taxa. My goal in this essay is to explore the idea that, largely independent of the aims of biodiversity informatics and well-funded international efforts, Wikipedia has emerged as potentially the best platform for fulfilling E. O. Wilson’s vision.
Received: 13 December 2008 / Accepted: 18 April 2009 / Published online: 13 December 2008
Molecular phylogeny of the endemic fern genera Cyrtomidictyum and Cyrtogonellum (Dryopteridaceae) from East AsiaDownload PDFAbstract
Cyrtomidictyum Ching and Cyrtogonellum Ching are two eastern Asian endemic genera whose taxonomic affinities and phylogenetic relationships have long been controversial. The main uncertainty surrounds the separation of the two genera from the species-rich genus Polystichum. Here we present a phylogenetic study focusing on the phylogenetic relationships of these polystichoid ferns. We reconstructed the relationships based on DNA sequence variation in four chloroplast genome regions, rbcL, atpB, and the intergenic spacers (IGS) rps4-trnS and trnL-trnF. Maximum likelihood and Bayesian inference analyses confirm earlier results that were based on less comprehensive taxon sampling and either only a single gene (rbcL) or two IGS (rps4-trnS and trnL-trnF). Cyrtomidictyum is the sister of the clade of polystichoid ferns that includes Cyrtogonellum, Cyrtomium subser. Balansana and three sections of Polystichum. Cyrtogonellum groups with several species of Polystichum, and constitutes the sister taxon to Polystichum sect. Sphaenopolystichum. We support the recognition of Cyrtomidictyum as circumscribed initially, rather than expansion of the genus to include either several Polystichum species or Cyrtogonellum, some Polystichum and Cyrtomium species. The monophyly of Cyrtomidictyum is supported by morphological characters such as once-pinnate leaves, free venation, prolongated leaf apices, and exindusiate sori. Two synapomorphic indels in the chloroplast genome, one 15-bp deletion in rps4-trnS, and one 3-bp insertion in trnL-trnF further differentiate Cyrtomidictyum from other polystichoid ferns. The close affinity of Cyrtogonellum to section Sphaenopolystichum of Polystichum s.s. is highly supported by molecular data. However, no shared morphological characters or molecular indels have been detected, although the distinctness of Cyrtogonellum is shown by a 13-bp insertion in the rps4-trnS alignment.
Received: 27 April 2009 / Accepted: 18 November 2009 / Published online: 27 April 2009
Two new species of Ligia Fabricius, 1798 (Crustacea: Isopoda: Ligiidae) from coasts of the Persian and Aden gulfsDownload PDFAbstract
Two new species of Ligia are described, L. persica sp. nov. from the Persian Gulf and L. yemenica sp. nov. from the Gulf of Aden. Ligia persica occurs along the northern coasts of the Persian Gulf and around some Iranian islands such as Qeshm and Kish. A comparison of SEM micrographs shows that the shape and ornamentation of distal parts of the appendix masculina are reliable characters for the identification of morphologically similar Ligia species. They are species-specific and of great importance in the taxonomy of the genus.
Received: 29 March 2010 / Accepted: 20 September 2010 / Published online: 29 March 2010
Establishing species and species boundaries in Sabellastarte Krøyer, 1856 (Annelida: Sabellidae): an integrative approachDownload PDFAbstract
Sabellastarte Krøyer, 1856 (Sabellidae), a morphologically homogeneous group distributed in warm and temperate coasts of the Indo-Pacific and Caribbean Sea, is characterized by the presence of a unique combination of features. To date, the genus comprises eight species, but morphological characters traditionally used in diagnostics have shown intra-specific variability, making species boundaries and distributions unclear. The present study constitutes the first attempt to test the monophyly of Sabellastarte and its relationships to other sabellid genera by combining molecular (COI and 16S) and morphological data. Results include placement of a clade containing Stylomma, Sabella, Branchiomma and Bispira as the sister group to Sabellastarte. Phylogenetic analyses and genetic divergence among specimens from several localities around the world indicate the presence of at least six lineages within Sabellastarte. In the context of a discussion of species boundaries and diagnostic features, the distribution of some of those lineages can be explained by the presence of cryptic species and potential introductions.
Received: 10 December 2009 / Accepted: 20 April 2010 / Published online: 10 December 2009
Phylogeny, molecular ecology and taxonomy of southern Iberian lineages of Triops mauritanicus (Crustacea: Notostraca)Download PDFAbstract
We investigated the phylogeography of the main lineages in the tadpole shrimp Triops mauritanicus Ghigi in the south-western Iberian Peninsula, using mitochondrial 12S and 16S rDNA sequences. Our results indicate that a fourth, hitherto unknown main phylogenetic lineage occurs in Iberia, so that in total, the species is divided into six distinct clades, comprising T. m. mauritanicus, T. m. simplex Ghigi, and four as yet unnamed lineages that appear to be endemic to Iberia. Percentages of sequence divergence among the main clades in T. mauritanicus reach the range reported for recognized species in other notostracan lineages. A thorough morphological investigation also revealed that the differentiation among these lineages is higher than previously thought, and that populations of three of the main clades within T. mauritanicus can be reliably separated from each other and from the remaining lineages based on the morphology of adult males. The remaining clades also show a significant level of morphological differentiation, but include a certain proportion of populations for which the additional application of molecular methods is needed for a reliable determination. The geographic distributions of 12S haplotypes are indicative of frequent dispersal events and gene flow among populations belonging to the same main lineage, but give no evidence of recent migration events among different main lineages, suggesting that there is no gene flow among the latter. Our data thus suggest that the six main lineages within T. mauritanicus represent distinct species. We therefore describe the Iberian lineages as T. baeticus Korn n. sp., T. emeritensis Korn & Pérez-Bote n. sp., T. gadensis Korn & García-de-Lomas n. sp., and T. vicentinus Korn, Machado, Cristo & Cancela da Fonseca n. sp., and reinstate T. simplex Ghigi to full species status. Our data confirm the general, previously recognized pattern of a lower dispersal probability in gonochoric Triops taxa. However, we found evidence that passive dispersal in Triops may be further complicated by a strong habitat dependence of dispersal probability, mediated by prevailing dispersal vectors.
Received: 07 September 2009 / Accepted: 17 November 2009 / Published online: 07 September 2009
Evolutionary and developmental aspects of phalangeal formula variation in pig-nose and soft-shelled turtles (Carettochelyidae and Trionychidae)Download PDFAbstract
In order to examine the evolution of the phalangeal formula in a diverse clade of turtles, including hyperphalangy as a rare condition in this group, we studied 210 specimens representing all extant genera of Trionychidae and their sister taxon, Carettochelyidae. Both groups consist of highly aquatic species with elongated autopods that are either paddle-like (Trionychidae) or transformed to flippers (Carettochelyidae). Phalangeal formulae were obtained mostly by radiographs of alcohol-preserved or dry specimens, as well as by direct counts from skeletons. All trionychids and Carettochelys are pentadactylous, but their phalangeal formulae differ. Carettochelys exhibits the turtle-plesiomorphic state (manus and pes: 2-3-3-3-3), with no variation in adults. Trionychids exhibit intraspecific variation, ranging from 2-3-3-3-2 to 2-3-3-6-5 for the manus, and from 2-3-3-3-2 to 2-3-3-5-3 for the pes. The extant Carettochelys as well as the Middle Eocene Allaeochelys crassesculpta are characterized by an elongation of phalanges, whereas trionychids consistently have shorter phalanges. All trionychid genera exhibit some degree of hyperphalangy in digits IV and V, in both the manus and pes. Phalanges of the clawed digits I–III are very robust compared to phalanges of the non-clawed digits IV and V. The latter contribute significantly to the enlargement of the paddle by their additional phalanges. We hypothesize that this phalangeal pattern is coupled with prolongation of growth processes in the non-clawed digits. The differences in autopod morphology between carettochelyids and trionychids reflect different locomotor patterns related to different natural histories (elongated flippers for high-speed escape in the mainly herbivorous Carettochelys; broad paddles for rapid turns during hunting in the mainly carnivorous trionychids). The autopod of Pelodiscus sinensis is proposed as an experimental model to examine the developmental basis of adult autopod variation.
Received: 03 August 2009 / Accepted: 02 November 2009 / Published online: 03 August 2009
A new genus and species of African Phaneropterinae (Orthoptera: Tettigoniidae), with data on its ecology, bioacoustics and chromosomesDownload PDFAbstract
A new genus is proposed for a new East African Phaneropterinae species, Lunidia viridis, occurring on Mt. Kilimanjaro, Tanzania. Based on 33 records, notes on distribution and habitat are given, as well as acoustical data provided. Climate and vegetation parameters obtained along several transects on Mt. Kilimanjaro were evaluated describing the ecological niche of the new species. This interdisciplinary approach allows not only a profound characterisation of the ecological demands of the new genus but also predictions of the potential distribution area, which is tested for the first time for an African bush cricket species. Lunidia viridis n. gen. n. sp. occurs within humid and perhumid forests and Chagga home gardens, avoiding subhumid conditions on the mountain. It is found from 1,330 m upwards on the southern slopes, whereas the same ecological conditions are expressed from 1,930 m upwards on the drier northern slopes. Lunidia viridis has an unusually complex and variable song, which is described from field and laboratory recordings. The FISH technique for characterizing chromosomes is applied for the first time for an African species; L. viridis exhibits a karyotype typical for most Tettigoniidae.
Received: 19 September 2009 / Accepted: 20 January 2010 / Published online: 19 September 2009
Skeletogenesis and sequence heterochrony in rodent evolution, with particular emphasis on the African striped mouse, Rhabdomys pumilio (Mammalia)Download PDFAbstract
Data documenting skeletal development in rodents, the most species-rich ‘order’ of mammals, are at present restricted to a few model species, a shortcoming that hinders exploration of the morphological and ecological diversification of the group. In this study we provide the most comprehensive sampling of rodent ossification sequences to date, with the aim of exploring whether heterochrony is ubiquitous in rodent evolution at the onset of skeletal formation. The onset of ossification in 17 cranial elements and 24 postcranial elements was examined for eight muroid and caviomorph rodent species. New data are provided for two non-model species. For one of these, the African striped mouse, Rhabdomys pumilio, sampling was extended by studying 53 autopodial elements and examining intraspecific variation. The Parsimov method of studying sequence heterochrony was used to explore the role that changes in developmental timing play in early skeletal formation. Few heterochronies were found to diagnose the muroid and caviomorph clades, suggesting conserved patterning in skeletal development. Mechanisms leading to the generation of the wide range of morphological diversity encapsulated within Rodentia may be restricted to later periods in development than those studied in this work. Documentation of skeletogenesis in Rhabdomys indicates that intraspecifc variation in ossification sequence pattern is present, though not extensive. Our study suggests that sequence heterochrony is neither pivotal nor prevalent during early skeletal formation in rodents.
Received: 13 April 2010 / Accepted: 14 June 2010 / Published online: 13 April 2010
Alternative nomenclatural procedures as a potential benefit to natural history collectionsDownload PDFAbstract
It has been argued that adopting alternative nomenclatural procedures would jeopardize the importance of natural history collection by relegating reference specimens to a secondary role. Based on published statements and applications, the present contribution argues that reference specimens are an essential aspect of both the PhyloCode and the cladotypic procedures. Consequently, the latter procedures might actually result in a revival of interest in those collections, mostly by augmenting the number of reference specimens and, for the cladotypic approach, by necessitating appropriate curation and access to up-to-date research facilities.
Received: 11 August 2009 / Accepted: 28 October 2009 / Published online: 11 August 2009
Cryptic species of Notophyllum (Polychaeta: Phyllodocidae) in Scandinavian watersDownload PDFAbstract
The phyllodocid polychaete Notophyllum foliosum occurs in two colour morphs in Swedish and Norwegian waters, one palish yellow to grey form with black patches that is restricted to deeper waters and often associated with reefs of the deep-water coral Lophelia pertusa, and one usually yellow-orange form with black patches and white spots that is usually encountered on more shallow bottoms. We have sampled the two forms from sympatric occurrences in Norway, and the shallow form from the Swedish west coast. Phylogenetic and haplotype analyses based on the mitochondrial cytochrome c oxidase subunit I (COI) gene and the nuclear internal transcribed spacer region (ITS1-5.8SrDNA-ITS2) unequivocally indicate that the two forms represent different species. We apply the name N. foliosum (Sars, 1835) to the ‘shallow form’, and propose N. crypticum n. sp. for the ‘deep form’. A lectotype is fixed for N. foliosum.
Received: 28 September 2009 / Accepted: 22 April 2010 / Published online: 28 September 2009
Head morphology of Osmylus fulvicephalus (Osmylidae, Neuroptera) and its phylogenetic implicationsDownload PDFAbstract
External and internal head structures of Osmylus fulvicephalus were examined and described in detail. Exo- and endoskeleton, musculature, elements of the central nervous system and tracheae are compared to conditions found in other groups of Neuropterida and other endopterygote lineages. Thirty-six adult cephalic characters were compiled, combined in a datamatrix with 64 characters of the larval head, and analysed cladistically. Mainly because many data on adults remain missing, most branches in the cladogram are mostly or exclusively supported by larval features. The shortening of the mesal mandibular wall and the resulting anterior shift of the adductor tendon possibly constitute an adult groundplan apomorphy of Neuropterida. Raphidioptera and Megaloptera share distinct prognathism and the presence of a sclerotised gula. However, the orthognathous head and the absence of a gula resulted as autapomorphies of Neuroptera in our analyses. Further potential autapomorphies are the asymmetry of the mandibles as well as the respective presence of dorsolateral furrows on the head capsule, of a shovel-like extension on the ventral mandibular cutting edge, and of a row of stiff hairs on the mandible’s ventral surface. The systematic affinities of Osmylidae remain ambiguous. Osmylus is mainly characterised by plesiomorphic features of the adult head such as a complete endoskeleton, long filiform antennae, largely unmodified orthopteroid mouthparts, and particularly the nearly complete set of muscles. The placement with a clade also comprising Hemerobiidae and Chrysopidae is poorly supported. The presence of a dense vestiture of long microtrichia on the distal galeomere resulted as a synapomorphy of the three families. An apparent plesiomorphy preserved in Osmylus but absent in all other groups of Neuroptera is the presence of well developed ocelli. The present study underlines the severe shortage of detailed morphological data on the adults. Intensive study of adult structures is required for a solid reconstruction of the phylogeny of Neuropterida, especially of the hemerobiform lineage of Neuroptera.
Received: 02 September 2008 / Accepted: 15 April 2009 / Published online: 02 September 2008
Interglacial refugia and range shifts of the alpine grasshopper Stenobothrus cotticus (Orthoptera: Acrididae: Gomphocerinae)Download PDFAbstract
A warming climate leads to shifts in distribution ranges to higher latitudes and altitudes. Consequently, cold-adapted alpine species can be trapped in interglacial Holocene refugia on high mountain summits if they fail to expand their ranges to the north. One example is the alpine grasshopper Stenobothrus cotticus. This species was assumed to be endemic to the southwestern Alps (France, Italy). However, we have found a second refugium in the Rila Mountains in southwestern Bulgaria. Analyses of the mitochondrial gene co1 and of phenotypic characters from morphology and behaviour did not reveal differences between the two geographically separated populations of S. cotticus studied. We suppose that S. cotticus had a wider distribution during colder periods, when its range was expanded to lower altitudes. This hypothesis is supported by the current distribution of the closely related montane S. rubicundulus.
Received: 22 May 2009 / Accepted: 28 August 2009 / Published online: 22 May 2009
A hands-on overview of tissue preservation methods for molecular genetic analysesDownload PDFAbstract
DNA studies have overwhelming importance in biological science. The aim of this paper is to present a compact and hands-on summary of widely available tissue preservation methods by listing dry, fluid/buffered and freezing techniques. Thereby, practical aspects, advantages and disadvantages, safety and feasibility issues of each method are discussed and compared.
Received: 19 April 2010 / Accepted: 08 October 2010 / Published online: 19 April 2010
Females do count: Documenting Chironomidae (Diptera) species diversity using DNA barcodingDownload PDFAbstract
Because the family Chironomidae, or non-biting midges, is one of the most species-rich groups of macroinvertebrates in freshwater habitats, species-level identifications of chironomids are important for biodiversity assessments in these ecosystems. Morphology-based species identifications from adult female chironomids usually are considerably more difficult than from adult males, or even impossible; thus, the females are often neglected in community assessments. We used DNA barcoding to investigate how inclusion of the females influenced the species count from springs and spring brooks at Sølendet Nature Reserve in Central Norway. By means of the barcodes we were able to identify 77.6% of the females to species by associating them with males from the study site or from other regions, whereas the remaining, unassociated females could be identified to genus level only. The number of recorded species increased by 27% when females were included. We also found that DNA barcoding is effective for the detection of taxonomically challenging species and species groups. Using DNA barcoding in combination with traditional taxonomy, we recognised at least five species new to science and three species and one genus new to Norway.
Received: 28 September 2009 / Accepted: 27 August 2010 / Published online: 28 September 2009
Genetic and morphological divergence among Gravel Bank Grasshoppers, Chorthippus pullus (Acrididae), from contrasting environmentsDownload PDFAbstract
Gravel Bank Grasshopper (Chorthippus pullus) populations inhabit two contrasting environments, pebbly gravel banks with scarce vegetation cover in mountainous areas along the Alps and lowland grasslands dominated by Common Heather (Calluna vulgaris). Heath populations of C. pullus have been rediscovered only recently, and show a distribution scattered across Central Europe. The wings are reduced in this species; thus, it has low potential for long-distance dispersal. We used sequence data on a newly developed non-coding nuclear marker from three gravel-bank and four heath populations to test whether grasshoppers from the two environments represent distinct lineages. Gravel-bank populations were studied in southern Germany (Bavaria), heath populations in eastern Germany (Brandenburg and Saxony) and Ukraine. We compared those genetic data with an analysis of variation in a suite of morphometric traits. Finally, we combined genetic and morphometric data to reconstruct a plausible scenario for the ecological shift observed in C. pullus. Our newly developed marker did not sort populations from contrasting environments in two monophyletic lineages. Nevertheless, we found a general lack of gene flow between the gravel-bank and heath populations. There was pronounced variation among populations in morphometric traits. That variation was partially partitioned by habitat type, and populations from the same habitat tended to be more similar than those from different habitats. Our data suggest that heath populations originated through northward expansion from multiple southern European refugia, and that the gravel-bank populations represent one of these sources. Patterns of genetic and morphometric divergence suggest that gravel-bank and heath populations may be in the process of incipient speciation.
Received: 28 August 2009 / Accepted: 06 September 2010 / Published online: 28 August 2009
Does allometry account for shape variability in Ephedrus persicae Froggatt (Hymenoptera: Braconidae: Aphidiinae) parasitic wasps?Download PDFAbstract
We analysed linear measurements on various parts of the body and the configuration of 11 landmarks on the wing in a large sample of Ephedrus persicae that had emerged from 13 aphid host species, to assess whether static allometry (a measure of the scaling relationship between traits in a population of individuals at the same ontogenetic stage) accounts for variation in body shape. The analysed specimens came from several localities in Europe, Asia Minor, Japan and South America, and cover a large portion of the distribution area of E. persicae. We found that allometry accounts for variation in body shape among different biotypes within the E. persicae group. The allometric slopes for head size (HD), petiolus width (PETW), mesoscutum width (MSC), and ovipositor sheath length (OVPL) diverged significantly among biotypes, indicating biotype-specific allometries. The analysis of allometric variation in wing shape showed that the pattern and direction of allometric changes also differed among individuals that had emerged from different hosts. Our results (observed divergences in the directions of allometric slopes of particular morphometric traits and wing shape) suggest that allometric relations within E. persicae are not conserved, so that allometry itself changes, evolving differently in aphid parasitoids that emerge from different hosts.
Received: 26 February 2009 / Accepted: 02 July 2009 / Published online: 26 February 2009
The world’s economically most important chelonians represent a diverse species complex (Testudines: Trionychidae: Pelodiscus)Download PDFAbstract
Pelodiscus is one of the most widely distributed genera of softshell turtles, ranging from south-eastern Siberia and Korea over central and southern China to Vietnam. Economically, Pelodiscus are the most important chelonians of the world and have been bred and traded in high numbers for centuries, resulting in many populations established outside their native range. Currently, more than 300 million turtles per year are sold in China alone, and the bulk of this figure comprises farmed Pelodiscus. Due to easy availability, Pelodiscus also constitutes a model organism for physiological and embryological investigations. Yet, diversity and taxonomy of Pelodiscus are poorly understood and a comprehensive investigation using molecular tools has never been published. Traditionally, all populations were assigned to the species P. sinensis (Wiegmann, 1834); in recent years up to three additional species have been recognized by a few authors, while others have continued to accept only P. sinensis. In the present study, we use trade specimens and known-locality samples from Siberia, China, and Vietnam, analyze 2,419 bp of mtDNA and a 565-bp-long fragment of the nuclear C-mos gene to elucidate genetic diversity, and compare our data with sequences available from GenBank. Our findings provide evidence for the existence of at least seven distinct genetic lineages and suggest interbreeding in commercial turtle farms. GenBank sequences assigned to P. axenaria (Zhou, Zhang & Fang, 1991) are highly distinct. The validity of P. maackii (Brandt, 1857) from the northernmost part of the genus’ range is confirmed, whereas it is unclear which names should be applied to several taxa occurring in the central and southern parts of the range. The diversity of Pelodiscus calls for caution when such turtles are used as model organisms, because the respective involvement of more than a single taxon could lead to irreproducible and contradictory results. Moreover, our findings reveal the need for a new assessment of the conservation status of Pelodiscus. While currently all taxa are subsumed under ‘P. sinensis’ and listed as ‘vulnerable’ by the IUCN Red List of Threatened Species, some could actually be endangered or even critically endangered.
Received: 26 August 2009 / Accepted: 26 March 2010 / Published online: 26 August 2009
Using compensatory base change analysis of internal transcribed spacer 2 secondary structures to identify three new species in Paramacrobiotus (Tardigrada)Download PDFAbstract
Species within the tardigrade genus Paramacrobiotus could be distinguished via an analysis of internal transcribed spacer 2 (ITS2) secondary structures. Sequences of P. richtersi and four populations previously treated under provisional names (Paramacrobiotus ‘richtersi group’ 1 to 4) from different continents were determined and annotated, and their secondary structures were predicted. A tree based on a combined sequence-structure alignment was reconstructed by Neighbor-Joining. The topology obtained is consistent with a tree based on a distance matrix of compensatory base changes (CBCs) between all ITS2 sequence-structure pairs in the global multiple alignment. The CBC analysis, together with 18S rDNA sequences, physiological, biochemical and biophysical data identified three species new to science that are morphologically indistinguishable from P. richtersi. These are formally described under the names Paramacrobiotus fairbanksi sp. nov., P. kenianus sp. nov., and P. palaui sp. nov.
Received: 15 July 2009 / Accepted: 30 March 2010 / Published online: 15 July 2009
On the phylogenetic position of the palaeopteran Syntonopteroidea (Insecta: Ephemeroptera), with a new species from the Upper Carboniferous of EnglandDownload PDFAbstract
A new syntonopterid, Anglolithoneura magnifica gen. et sp. n., is described from a siderite concretion (nodule) from the Late Carboniferous (Langsettian) of Lancashire County (UK). The new genus is diagnosed on hind wing venation and compared with other syntonopterid genera. The new species is the first syntonopterid formally described from the Late Carboniferous of Europe. The systematic positions of other potential Syntonopteroidea (Miracopteron mirabile, Bojophlebia prokopi, and specimens described in 1985 by J. Kukalová-Peck from Obora in the Czech Republic) are reconsidered. Wing venation synapomorphies are proposed for the Syntonopteroidea (sensu novo), and for a potential clade ((Ephemeroptera+Syntonopteroidea)+Odonatoptera) separated from the Palaeodictyopterida. The close relations of the new species with Lithoneura lameerei Carpenter, 1938 from Mazon Creek (Illinois, USA) provide additional support for a Euramerican connection during the Late Carboniferous.
Received: 30 July 2009 / Accepted: 16 January 2010 / Published online: 30 July 2009
Zoological nomenclature in the century of extinctions: priority vs. ‘usage’Download PDFAbstract
Our epoch is a crucial one for scientific knowledge of the organisms that live on our planet. The combination of the biodiversity crisis and the taxonomic gap results in taxonomic urgency. In this context, great attention should be paid to the nomenclatural rules helping taxonomists in their urgent task, rather than diverting their time and energy to secondary questions or debates. In zoology, the new criterion of ‘prevailing usage’, introduced in the 1999 edition of the Code of nomenclature to ‘protect’ some nomina, raises four kinds of problems: (1) it weakens the binding value and strength of the Code, thus indirectly bringing support to the development of alternative nomenclatural systems; (2) it encourages personal debates among taxonomists, giving undue importance to the ‘argument of authority’ in nomenclatural decisions; (3) it sends a wrong message to non-taxonomists as regards completion of the taxonomic work; (4) it acts as a threat against natural history museums, in devaluing onomatophores (type specimens), the conservation of which is one of their major ‘visible’ functions. In conclusion, it is suggested that ‘protection’ of some nomina ‘threatened’ by rules of the Code should be limited strictly to nomina well-known outside the small world of systematics. This would require new rules for the Code to clearly define categories of usage on the basis of objective criteria.
Received: 12 January 2010 / Accepted: 12 January 2010 / Published online: 12 January 2010
A decade of ODE: looking back and looking forwardDownload PDF