Received: 19 April 2005 / Accepted: 22 June 2007
Coral-inhabiting swimming crabs (Crustacea, Decapoda, Portunidae) of the Sudanese Red SeaDownload PDFAbstract
Brachyuran crabs show high species richness and constitute one of the most diverse biotic groups in coral reef communities. The present study examines the taxonomy and ecology (occurrence in particular coral habitats) of swimming crabs from the Sanganeb Atoll (Sudan) known for its high diversity of hermatypic corals. During two expeditions in the years 1991 and 1992, eleven species were collected directly from coral colonies or in baited traps in coral habitats: Carupa tenuipes Dana, 1852; Caphyra fulva Stephenson & Campbell, 1960; Portunus aff. iranjae Crosnier, 1962; Gonioinfradens paucidentata (A. Milne-Edwards, 1861); Thalamitoides quadridens A. Milne-Edwards, 1869; Thalamitoides spinigera Nobili, 1905; Thalamita cf. iranica Stephensen, 1945; Thalamita murinae Zarenkov, 1971; Thalamita prymna (Herbst, 1803); Thalamita quadrilobata Miers, 1884; and Thalamita savignyi A. Milne-Edwards, 1861. Thalamita murinae, had been recorded only once before and incompletely described; it is redescribed from the holotype. Together with Thalamita longifrons (A. Milne-Edwards, 1869) from the Pacific, it forms a distinct group of species living in complex coral habitats. This Th. longifrons group is revised; Th. spinimera Stephenson & Rees, 1967 and Th. yoronensis Sakai, 1969 are considered as new junior synonyms of Th. longifrons. The distribution of swimming crabs across the range of sampled habitats showed a characteristic pattern that did not simply reflect the sampling effort. Thalamitoides spinigera, a species endemic to the Red Sea and the Gulf of Aden, clearly preferred dead Stylophora habitats. Several hypotheses explaining preferences of particular species for Stylophora colonies are discussed. Inhabiting various coral habitats (which for many species can be substituted by rock, rubble or mussel clumps) is characteristic for the subfamilies Carupinae and Thalamitinae, whereas Portuninae are found there occasionally only.
Received: 10 July 2007 / Accepted: 14 November 2007
Phylogenetic analysis of the Echinoderidae (Kinorhyncha: Cyclorhagida)Download PDFAbstract
The phylogeny of the kinorhynch family Echinoderidae is analyzed using morphological characters and parsimony as the optimization criterion. Thirty-six characters were coded in a matrix with eleven echinoderid terminals, representing all echinoderid genera and six non-echinoderid outgroup taxa. The ingroup includes Polacanthoderes martinezi and Cephalorhyncha liticola, newly described in a separate paper. The resulting most parsimonious trees support Polacanthoderes as the most basal echinoderid genus, followed by an unresolved clade with non-monophyletic Fissuroderes and monophyletic Cephalorhyncha and Echinoderes.
Received: 12 April 2006 / Accepted: 20 August 2006
Hansenomysis anaramosae n. sp., a new suprabenthic mysid (Crustacea: Mysidacea: Petalophthalmidae) from the Bellingshausen Sea (Southern Ocean)Download PDFAbstract
A new petalophthalmid mysid, Hansenomysis anaramosae n. sp., is described from specimens sampled with a suprabenthic sled in the Bellingshausen Sea (Southern Ocean). Hansenomysis anaramosae is clearly distinguishable from its closest congener, H. angusticauda Tattersall, by the carapace sculpturing, the rostrum produced into a spine-like process, the shape and armature of the antennal scale, eyeplate, and telson. This new species is the fourth Hansenomysis species described from the Southern Ocean. A key to these Antarctic species is presented.
Received: 28 March 2007 / Accepted: 25 February 2008
Explaining the ‘anomalous’ distribution of Echinodium (Bryopsida: Echinodiaceae): Independent evolution in Macaronesia and AustralasiaDownload PDFAbstract
The peculiar disjunction between Macaronesia and Australasia of the morphologically isolated pleurocarpous moss genus Echinodium is one of the most prominent questions in bryology. Echinodium as traditionally circumscribed comprises six extant species, four restricted to the Macaronesian archipelagos and two confined to the Australasian/Pacific regions. Molecular phylogenetic analyses based on plastid trnLUAA intron and nuclear ribosomal ITS sequences indicate that Echinodium is polyphyletic and split into three groups. Three of the four Macaronesian species (E. spinosum and the single island endemics E. renauldii and E. setigerum) are closely related to each other and treated as Echinodium s.str. (Echinodiaceae). Further clarification of the relationships of Echinodium s.str. with Orthostichella, a segregate of Lembophyllaceae, is needed. The remaining Macaronesian species, E. prolixum, is transferred to Isothecium (Lembophyllaceae); this systematic position is also strongly supported by leaf characters. The two Australasian species, E. hispidum and E. umbrosum, are molecularly unrelated to the Macaronesian species and are transferred to Thamnobryum in the Neckeraceae. While the molecular data suggest that the peculiar distribution pattern of ‘Echinodium’ is an artefact, the striking morphological similarity observed in Macaronesian and Australasian species cannot be dismissed. Possible explanations are: (i) parallel morphological evolution of the ‘Echinodium habit’ in Macaronesia and Australasia, or (ii) retention of a set of plesiomorphic characters in non-related groups in relict habitats, the Macaronesian laurel forest and the austral temperate rain forests, respectively. Of these hypotheses, the evolutionary parallelism hypothesis seems more plausible for several reasons, which are discussed.
Received: 25 July 2006 / Accepted: 16 January 2007
Symbiosis between Symbiodinium (Dinophyceae) and various taxa of Nudibranchia (Mollusca: Gastropoda), with analyses of long-term retentionDownload PDFAbstract
Long-term retention of zooxanthellae in five different species belonging to two different nudibranch groups (Aeolidoidea and Dendronotoidea) was investigated. Specimens belonging to the species Phyllodesmium briareum, Phyllodesmium colemani, Phyllodesmium longicirrum, Pteraeolidia ianthina and Melibe engeli were cultivated for 70–270 days under various feeding conditions, and photosynthetic activity was analysed by taking pulse amplitude modulated (PAM) fluorometer measurements. All five species showed stable symbiosis and long-term retention of zooxanthellae. Interspecific differences are discussed. Morphological adaptations for housing zooxanthellae in the digestive glandular system were investigated and documented by histological means.
Received: 03 July 2006 / Accepted: 16 January 2007
Tetrablemmidae (Arachnida, Araneae), a spider family newly recorded from ChinaDownload PDFAbstract
The family Tetrablemmidae is reported for the first time from China, with five new species and one new genus. Lehtinenia gen. n., which is erected to accommodate Lehtinenia bicornis sp. n., is characterized by the modified embolus, special modifications on chelicerae, and a Tetrablemma-type vulva. The other four new species are: Ablemma prominens sp. n., Brignoliella caligiformis sp. n., Brignoliella maoganensis sp. n., and Tetrablemma brevidens sp. n., all collected from caves. A phylogenetic analysis of the subfamily Tetrablemminae based on 41 morphological characters shows that the tribe Brignoliellini is the most basal group in the subfamily, rather than the sister group to the tribe Fallablemmini. Lehtinenia gen. n. and the genera Ablemma, Sulaimania, and Maijana together form a monophyletic group.
Received: 11 April 2008 / Accepted: 19 June 2008
The gynostegium of Hoya spartioides (Apocynaceae – Asclepiadoideae): A striking case of incongruence between molecular and phenotypic evolutionDownload PDFAbstract
In molecular phylogenies Hoya spartioides, formerly regarded as the only species in a separate genus Absolmsia, is nested in the genus Hoya. It appears as sister to H. curtisii within a larger clade including H. lacunosa, H. imbricata, and H. caudata. In contrast to this close molecular relationship the floral morphology of H. spartioides differs considerably not only from that of its sister, H. curtisii, but from all other species of Hoya investigated so far. Of special interest are the differences in functional morphology of the pollinating apparatus, which in spite of its high degree of synorganization has undergone considerable evolutionary change in H. spartioides. Some of the new traits are even unique within the subfamily Asclepiadoideae as a whole. The large phenotypic distance between H. spartioides and H. curtisii is not reflected in corresponding differences in the tested marker genes, which raises the question of how the flower of H. spartioides has evolved.
Received: 30 January 2007 / Accepted: 22 April 2007
New species of grammitid ferns (Polypodiaceae, Polypodiopsida) from BoliviaDownload PDFAbstract
We describe 14 new species from the genera Ceradenia, Grammitis s.str., and Lellingeria, and provide keys to the Bolivian species of Ceradenia and Lellingeria.
Received: 20 November 2007 / Accepted: 16 June 2008
A cytogenetical study of Ischyroceridae (Amphipoda) allows the identification of a new species, Jassa cadetta sp. n., in the Lagoon of VeniceDownload PDFAbstract
Jassa cadetta sp. n. (Amphipoda: Ischyroceridae) is described from the Venice Lagoon, northern Adriatic Sea, and a key to Mediterranean members of the genus Jassa Leach is provided. The new species is separated from J. marmorata Holmes primarily by cytogenetics, differing in chromosome number (2n=10 in J. cadetta vs. 2n=12 in J. marmorata), karyotype morphology (FN=20 vs. FN=22), and chromosome location of 18S-5.8S-28S ribosomal cistrons. Cytogenetic analysis of Ischyrocerus anguipes Krøyer (2n=10, FN=18) gives a first insight into karyological diversity among Ischyroceridae. Analysis of random amplified polymorphic DNA markers confirms the distinction between J. cadetta sp. n. and J. marmorata.
Received: 03 October 2006 / Accepted: 29 November 2007
Phylogenetic position of the montane treefrog Polypedates variabilis Jerdon, 1853 (Anura: Rhacophoridae), and description of a related speciesDownload PDFAbstract
Since its original description, the Indian treefrog species Polypedates variabilis Jerdon, 1853 has been assigned variously to one of the widespread genera Polypedates Tschudi, 1832, Rhacophorus Kuhl & van Hasselt, 1822, and Philautus (Kirtixalus) Dubois, 1987. Here we present phylogenetic analyses based on 1.4kb of mitochondrial DNA showing that P. variabilis and a previously undescribed relative are not nested within any of those genera, but stem from a lineage that originated relatively early in the rhacophorid radiation. We propose the name Ghatixalus gen. n. for this lineage, whose known members are restricted to high altitudes in the Western Ghats of India. The sister species of G. variabilis (Jerdon), comb. n. is described as Ghatixalus asterops sp. n. The morphological and ecological features of both species are discussed.
Received: 13 July 2007 / Accepted: 16 May 2008
Evolutionary history of treecreeper vocalisations (Aves: Certhia)Download PDFAbstract
Since the vocalisations of passerine birds are in general a good means to separate taxa when external morphological differences are few, song and call recordings of 33 treecreeper (Certhia) taxa were sonagraphed and their parameters analysed. The vocalisations show low intra-individual and intra-population variation. Phylogenetic evolutionary units at the population level were delimited by time, frequency and syntax parameters by means of principal-component and discriminant analyses. Traits of territorial song were traced on a phylogenetic tree based on cytochrome b sequences, and a mean acoustic character difference was calculated. All presently recognised nine species could be distinguished clearly from one another by their vocalisations. Subspecies not included in the molecular phylogeny are affiliated with the correct species based on statistical analysis. The obvious subdivision of Certhia species into two groups according to the syntax of their song verses, trill and motif singers, is corroborated by different findings: a high phylogenetic signal in the characters concerned (highest homoplasy index values for trill characters), discriminant analyses for song and call measurements, and a cladistic analysis based on song characters. Innate calls turned out to be less suitable for studies at a low taxonomic level than learnt territorial songs, which require social interactions for their species-specific formation.
Received: 24 October 2006 / Accepted: 04 April 2007
Africa goes Europe: The complete phylogeography of the marbled white butterfly species complex Melanargia galathea/M. lachesis (Lepidoptera: Satyridae)Download PDFAbstract
Climatic oscillations influence the distribution of species in time. Thermophilic species survived the ice ages in refugia around the Mediterranean. Northern Africa is one of the possibly important refugia. In this study we test the genetic differentiation between northern African and European populations, using the marbled white butterfly species complex, Melanargia galathea/M. lachesis, as a model. We studied 18 allozyme loci in 876 individuals from 23 populations representing a major part of Europe (northern Spain to Romania) and the western part of northern Africa (Atlas Mountains). The African populations resemble the European ones in allelic richness; their genetic diversity is higher than in Europe. Cluster analysis discriminated five European genetic groups: M. lachesis, a western European lineage, and three eastern European lineages. However, the African samples did not form a separate cluster within this phenogram, but clustered randomly within the Balkan/southeastern European groups. The genetic differentiation among the African populations (FST 8.8%) was higher than that within any of the European lineages (FST 2.6–5.5%). The high genetic diversity and the relatively strong differentiation of the four African populations sampled in a comparatively limited area of the Atlas Mountains indicate that the most probable origin of M. galathea is northern Africa, with its sibling species, M. lachesis, evolving in parallel in Iberia. Most probably, M. galathea colonised Europe first during the Eem interglacial, some 130ky ago. Since M. lachesis must have existed on the Iberian peninsula during that period already, M. galathea should have reached Europe via Italy. The genetic differentiation to distinct groups in Europe most probably evolved during the following Würm glacial period.
Received: 08 November 2006 / Accepted: 17 March 2007
Phylogeny of the millipede genus Sphaeriodesmus Peters, 1864 (Polydesmida: Sphaeriodesmidae) based on morphological charactersDownload PDFAbstract
In order to understand the evolutionary relationships among the species encompassed within the genus Sphaeriodesmus Peters, 1864, a cladistic analysis including 63 species was conducted. Ninety-five morphological characters were used for the phylogenetic reconstruction. The results suggested that the current composition of the genus Sphaeriodesmus does not circumscribe a monophyletic group; instead, the genera Eusphaeriodesmus, Colobodesmus, and Proeilodesmus are here synonymized under Sphaeriodesmus. Although raw morphological data had suggested the genus Lophocyclus as the sister taxon of Sphaeriodesmus, the phylogenetic analysis under implied weight identified the genus Cyphodesmus as the taxon most closely related to Sphaeriodesmus. Sphaeriodesmus isolatus Chamberlin, 1940 is a subjective synonym of Sphaeriodesmus conformans Chamberlin, 1925. The putative subdivisions previously proposed within Sphaeriodesmus do not hold as monophyletic either. Low stability was observed concerning the higher-level phylogenetic relationships of Sphaeriodesmus. Sphaeriodesmus crucis (Loomis, 1974), S. mecistonyx (Hoffman, 1990), and S. triramus (Kraus, 1954) are new combinations.
Received: 07 May 2007 / Accepted: 15 November 2007
Range size variation and diversity distribution in the vascular plant flora of the Eurasian ArcticDownload PDFAbstract
The distribution ranges of Eurasian arctic vascular plants are studied to identify and characterise significant range types and their distribution along longitudinal and latitudinal gradients, and to analyse the range size distribution of arctic plants. We also address the distribution of plant diversity in the Eurasian Arctic and possible environmental reasons for the patterns observed. Cluster and correlation analyses are conducted on a distribution database established for 1690 vascular plants observed in the Eurasian Arctic. The database records occurrences of the species separately for each of 184 partial areas encompassing almost the entire Holarctic. Highest species numbers of Eurasian arctic plants were observed outside the Arctic, namely in the high mountain ranges of Europe, Siberia and the Far East. Within the Eurasian Arctic, highest species numbers were observed in the European Arctic and Chukotka. The species of the entire Eurasian Arctic could be affiliated with 15 range types. These range types revealed that the Eurasian arctic flora has three major constituents: endemics and sub-endemics, species of three southern high mountain ranges, and widespread species. A principal ‘source of origin’ contributing to the diversity of the Eurasian arctic flora was not evident. Widespread species are more abundant in the western than in the eastern Eurasian arctic flora, where endemics and sub-endemics prevail. The current climate of the northern hemisphere, not only vegetation history, is identified as an important factor in shaping these patterns.
Received: 04 April 2008 / Accepted: 25 September 2008
DNA taxonomy of Swedish Catenulida (Platyhelminthes) and a phylogenetic framework for catenulid classificationDownload PDFAbstract
Specimens of Catenulida were collected at 34 localities in Sweden. We used 18S rDNA, 28S rDNA, ITS-5.8S, and cytochrome oxidase I (COI) nucleotide sequences to infer phylogeny from parsimony jackknifing and Bayesian analysis. Our dataset contained 74 ingroup terminals and 5111 characters. The results show a basal split between a clade consisting of the marine Retronectidae+the limnic Catenulidae, and a second clade consisting of the limnic Stenostomidae. The hypothesis of the marine Retronectidae as the sister group of the limnic Catenulida is rejected. The recently introduced genus Anokkostenostomum Noreña, Damborenea & Brusa, 2005 results as non-monophyletic, and Suomina Marcus, 1945 as a group inside Catenula Dugès, 1832. Therefore, we propose to render Anokkostenostomum a new junior synonym of Stenostomum Schmidt, 1848, and Suomina a new junior synonym of Catenula. Consequently, the new combinations Catenula evelinae (Marcus, 1945), Catenula sawayai (Marcus, 1945), and Catenula turgida (Zacharias, 1902) are proposed, and 14 species are returned to their original genus, Stenostomum. The molecular phylogenetic hypothesis is used to identify and discriminate catenulid species. In our material, we found 12 species of Catenulida new to Sweden, and four species new to science, all of which are distinguishable by morphological characters.
Received: 28 March 2006 / Accepted: 08 November 2006
A new discovery of Novechiniscus armadilloides (Schuster, 1975) (Tardigrada, Echiniscidae) from Utah, USA with considerations on non-marine Heterotardigrada phylogeny and biogeographyDownload PDFAbstract
The discovery of a new population of the non-marine heterotardigrade Novechiniscus armadilloides from Utah, USA, allowed us to reanalyse the species by means of scanning electron microscopy and differential interference contrast microscopy. This analysis confirmed the presence of bar shaped, unpaired segmental plates and of a long filament E in addition to the filament A always present in the class Heterotardigrada. It also provided additional information on characters not explicitly cited in the previous descriptions of this monotypic genus, such as details of the head cirri and clavae, details of the buccal tube and pharyngeal bulb, sculpture of the dorso-lateral and leg plates, details of the claws. The population is bisexual, but no secondary sexual dimorphism was observed. The male and female gonopores were described. New characters such as red eyes and red body colour were used in analysing the phylogeny of the family Echiniscidae. The phylogeny and biogeography of non-marine heterotardigrades provide intriguing questions for further research.
Received: 08 March 2007 / Accepted: 12 December 2007
A taxonomic study of Chinese Nematogmus species (Araneae, Linyphiidae)Download PDFAbstract
Four species of Nematogmus Simon, 1884 from China were studied: N. sanguinolentus (Walckenaer, 1842; the type species), N. digitatus Fei & Zhu, 1994 (re-examined from its type material), N. longior sp. n., and N. membranifer sp. n. Descriptions of the new and redescriptions of the previously known species are provided, as well as the recorded distributions of all four species in China.
Received: 23 June 2008 / Accepted: 01 September 2008
Computer-based 3D anatomical reconstruction and systematic placement of the mesopsammic gastropod Platyhedyle denudata Salvini-Plawen, 1973 (Opisthobranchia, Sacoglossa)Download PDFAbstract
The small marine interstitial gastropod species Platyhedyle denudata Salvini-Plawen, 1973 has a dorsoventrally flattened, worm-like body without a shell and head tentacles; its systematic position was enigmatic. Wawra's [1979. Zur systematischen Stellung von Platyhedyle denudata Salvini-Plawen, 1973 (Opisthobranchia, Gastropoda). Z. Zool. Syst. Evolutionsforsch. 17, 221–225] anatomical redescriptions based on paraffin-embedded histology preparations indicated the original description of P. denudata to be erroneous in many essential features. The present study uses newly collected specimens from the Mediterranean type locality, Secche della Meloria, Italy, for serial semi-thin histological sectioning. All major organ systems of P. denudata are reconstructed three-dimensionally with AMIRA software. Platyhedyle denudata is a simultaneous hermaphrodite with an androdiaulic, complex genital system lacking a receptaculum seminis. A heart could not be detected; the nephric duct opens into the intestine. The central nervous system is postpharyngeal and the cerebropleural ganglia are completely fused. The visceral loop is short, showing three distinct ganglia which connect to an additional, presumably osphradial ganglion, and to a posteriorly situated genital ganglion. Aggregations of precerebral accessory ganglia are present. The originally described jaws could not be detected. An ascus for storage of worn radula teeth clearly indicates that P. denudata is a sacoglossan. The digestive gland of the mesopsammic P. denudata resembles that of the depressed, tentacle-less semi-terrestrial sacoglossan Gascoignella aprica Jensen, 1985 by forming two long branches that are connected at the rear end. In G. aprica, the digestive-gland rami are separated by a unique median septum, which is described here, too, as part of the muscle system in P. denudata. The shared, most likely synapomorphic presence of this septum strongly supports the monophyly of a Platyhedyle+Gascoignella clade in a sacoglossan family Platyhedylidae.
Received: 19 June 2006 / Accepted: 11 June 2007
Pseudotachidiidae (Copepoda: Harpacticoida) from the Angola Basin and the Antarctic deep sea, with the description of a new species of Paradanielssenia Soyer, 1970Download PDFAbstract
The species diversity of Copepoda Harpacticoida in the deep sea of the Angola Basin (DIVA I expedition) and in the Weddell Sea (ANDEEP II expedition) is investigated. In both areas, the Pseudotachidiidae Lang, 1936, together with Ameiridae Monard, 1927, Argestidae Por, 1986 and Ectinosomatidae Sars, 1903, are richest in species and numbers of individuals. From two DIVA stations and from ANDEEP station 138, all adult specimens have been determined at the level of ‘working species’. Pseudomesochrinae Willen, 1996, represented mainly by the single taxon Pseudomesochra T. Scott, 1902 and Paranannopinae Por, 1986 turned out to be the ‘dominant’ taxa in terms of abundance and species number. A new species of Paradanielssenia Soyer, 1970 is described, which was encountered in relatively high abundances in almost every replicate sample from the DIVA stations. A key to the known species of the taxon Paradanielssenia is given.
Received: 14 May 2008 / Accepted: 25 August 2008
Into the canyons: The phylogeography of the Malagasy frogs Mantella expectata and Scaphiophryne gottlebei in the arid Isalo Massif, and its significance for conservation (Amphibia: Mantellidae and Microhylidae)Download PDFAbstract
Scaphiophryne gottlebei and Mantella expectata are two endemic and threatened frog species that live syntopically in the arid Isalo Massif in southern Madagascar. They share large parts of their distribution areas but differ in their natural history. Scaphiophryne gottlebei is more often found in canyons, while M. expectata prefers open habitats. Using samples from their known distribution areas, we investigated the genetic variability of these species by analyzing an approximately 600 base-pair fragment of the mitochondrial cytochrome b gene. Both species include a few widespread and common haplotypes as well as a number of other, geographically restricted ones. However, M. expectata exhibits more geographic substructure than S. gottlebei, in which one main haplotype represents individuals from various localities across the largest part of the distribution range. Comparing populations inside and outside of the Parc National de l’Isalo showed that the park does not harbour the bulk of the overall genetic diversity of the two species. These results emphasize the importance of so far unprotected habitats for the conservation of genetic variation in the endemic fauna of the Isalo region and of Madagascar in general.
Received: 14 March 2008 / Accepted: 11 July 2008
Phylogeny of Catenulida and support for PlatyhelminthesDownload PDFAbstract
Molecular studies have shown that Platyhelminthes is polyphyletic, placing Rhabditophora within Lophotrochozoa, whereas Acoela and Nemertodermatida are separate early bilaterian branches. However, there has been little evidence to support the position of Catenulida, a group that was traditionally classified within Platyhelminthes. In Ehlers’ pioneering cladistic system of the Platyhelminthes they were placed as the earliest clade. Other morphologists have considered the Catenulida as an early bilaterian clade separate from Rhabditophora, a position that was supported in an early molecular study. Subsequent molecular phylogenetic studies, which placed Catenulida as the sister group of Rhabditophora with no or low branch support, included 18S rDNA data from only one or two catenulid species. The aims of the present study were (1) to test the putative sister-group relationship of Catenulida and Rhabditophora by improving the taxon sampling of molecular data spanning a larger part of catenulid taxonomic diversity and (2) to provide a phylogenetic framework for the systematization of Catenulida. Twelve catenulid species were sampled around Sweden. Both the 18S rDNA gene and the 28S rDNA gene were sequenced and analysed in a Metazoa-wide data set within parsimony and Bayesian frameworks. The results unambiguously support Catenulida as the sister group of Rhabditophora within Lophotrochozoa. Parsimony-based inferences about the common ancestor of Catenulida and Rhabditophora are presented. A definition of the name Platyhelminthes is suggested.
Received: 19 January 2006 / Accepted: 22 December 2006
Molecular phylogeny of panorpodid scorpionflies: An enigmatic, species-poor family of Mecoptera (Insecta)Download PDFAbstract
The Panorpodidae are one of the species-poor taxa in Mecoptera, but explanation of the puzzling vicariant distribution of the two subordinated genera, Brachypanorpa in the USA and Panorpodes in East Asia and western North America, is a rewarding task. This first phylogenetic analysis of the Panorpodidae is based on 3661 aligned nucleotide positions and contains all described taxa of Panorpodidae, with the exception of two Panorpodes species inhabiting Asia. Five genes, three mitochondrial and two nuclear, were used in separate as well as in a combined analysis. Bayesian inference and parsimony analysis both led to congruent trees, but the different gene partitions were incongruent in that Panorpodes resulted as either paraphyletic or monophyletic. Based on our molecular data, the genus assignment of Panorpodes colei Byers, 2005 is probably correct despite the species’ isolated occurrence in western North America. Based on morphological and molecular data, we recommend further research on a new Brachypanorpa population, which would probably lead to the description of a new species.
Received: 28 July 2008 / Accepted: 13 October 2008
Molecular phylogeny and divergence times of ancient South American and Malagasy river turtles (Testudines: Pleurodira: Podocnemididae)Download PDFAbstract
The eight extant podocnemidid species are the last survivors of a speciose ancient group of turtles known to have existed since the Cretaceous. One species, representing the monotypic genus Erymnochelys, occurs on Madagascar; the remaining seven species are confined to South America (Peltocephalus: one species; Podocnemis: six species). Phylogenetic relationships of all extant species were reconstructed from six mitochondrial (3385bp) and six nuclear DNA fragments (4115bp) in separate and combined analyses (Bayesian inference, Maximum Likelihood, Maximum Parsimony). In a total evidence approach for all concatenated genes, all methods yielded the same well-supported phylogenetic hypothesis for the three basal lineages. The Malagasy genus Erymnochelys is sister to the South American Podocnemis, and Peltocephalus constitutes the sister taxon to Erymnochelys+Podocnemis. Within Podocnemis, P. unifilis+(P. erythrocephala+P. lewyana) constitute a well-supported crown clade; P. sextuberculata, P. vogli, and P. expansa were revealed as successive sister taxa. According to Bayesian relaxed molecular clock calculations calibrated with fossil evidence, Peltocephalus originated during a period of the Late Cretaceous (∼86mya), when a contiguous Gondwana landmass exclusive of Africa is likely to have still existed. The Late Cretaceous split between Erymnochelys and Podocnemis (∼78mya) coincides with the supposed submergence of the land bridge between Madagascar and Antarctica+South America, suggesting that the origin of those genera is linked to this vicariant event. The extant Podocnemis species evolved from the Late Eocene (∼37mya) to the Middle Miocene (∼15mya), during a phase characterized by dramatic global cooling, aridification, and massive Andean uplift.
Received: 21 September 2006 / Accepted: 01 June 2007
Can heterochrony help explain the high morphological diversity within the genus Niphargus (Crustacea: Amphipoda)?Download PDFAbstract
Postembryonic development of nine species of Niphargus (Crustacea: Amphipoda) was studied, with spine development and shifts in allometric growth being combined in developmental sequences that were compared across species. The developmental sequences show high diversity with respect to the position of individual events in the sequence, as well as a high frequency of events being inapplicable in some species. Within Niphargus, the highest degree of independence between events occurs mainly in early mid-aged instars, where the shifts in position are both the largest in magnitude and also the most frequent in occurrence. Constructive troglomorphic features of subterranean species were inferred to develop more because of accelerated growth rather than a delayed offset of growth. Shifts in both relative timing and growth rate appeared to have played a role in the evolution of sexually dimorphic elongated appendages. Growth patterns differed greatly between species for individual sexually dimorphic and troglomorphic traits, hinting at their possible independent origin. The independence between developmental events that was generally apparent might indicate the existence of an important genetic basis for the extreme intrageneric morphological variation arising from numerous highly variable body parts being combined in a ‘mosaic’ manner. Moreover, we suggest that the overall diversity of the genus might actually be underestimated in light of possible convergent features accompanied by ‘cryptic’ speciation. We conclude that both sequential and growth heterochrony appear to have played a key role in the evolution of Niphargus, the most diverse genus of freshwater amphipods. A preliminary list of heterochronic characters is provided.
Received: 22 January 2008 / Accepted: 28 May 2008
Reconstruction of the neuromuscular system of the swimming-type larva of Loxosomella atkinsae (Entoprocta) as inferred by fluorescence labelling and confocal microscopyDownload PDFAbstract
Entoprocta is one of the most enigmatic phyla of the Animal Kingdom. The morphology of their larvae has been little investigated, with details on the larval musculature lacking entirely and immunocytochemical data on the larval nervous system available for only 2 species. Here, we provide the first detailed study of the muscular bauplan and the serotonergic nervous system of an entoproct swimming-type larva. The overall muscular architecture of the larva of Loxosomella atkinsae Bobin & Prenant, 1953 is complex and includes several sets of ring, longitudinal, and diagonal muscles. The dorsal region of the larva (episphere) and the apical organ comprise an outer layer of tightly packed ring muscles. Beneath this layer lie sets of prominent longitudinal and diagonal muscles that run in dorso-ventral direction. The prototrochal musculature is composed of compact layers of outer ring and inner longitudinal muscles. The serotonergic nervous system consists of 3–4 flask-shaped serotonergic cells in the apical organ and a paired nerve passing the frontal neuropil and connecting to the serotonergic prototroch nerve ring. We show here that the entoproct larval stage, in addition to the adult stage, provides several morphological characters for evolutionary inferences. Comparative data on entoproct swimming-type larvae suggest ring and longitudinal muscles underlying the prototroch, a paired main longitudinal muscle, and an unpaired abfrontal longitudinal muscle as part of the ancestral muscular groundpattern of loxosomatid swimming-type larvae.
Received: 27 April 2007 / Accepted: 19 December 2007
Features of the first known association between Syllidae (Annelida, Polychaeta) and crustaceansDownload PDFAbstract
This paper reports on a specimen of Haplosyllides (Polychaeta: Syllidae) living attached to the pleopod of a female of the pontoniine shrimp Platycaris latirostris Holthuis, 1952, which in turn lives symbiotically with the scleractinian coral Galaxea astreata (Lamarck, 1816) on the Vietnamese coasts of the South China Sea. The worm–shrimp association is considered as ectoparasitic, thus representing the first of its kind observed between polychaetes and shrimps, but also between syllids and crustaceans in general. This mode of life strongly differs from that of the single Haplosyllides species currently accepted as valid, H. floridana Augener, 1924 from Florida and Cuba (a strict sponge endosymbiont). The discrepancy casts some doubt on the synonymy of H. floridana with Syllis (Haplosyllis) aberrans (described from Vietnam).
Received: 23 July 2007 / Accepted: 14 November 2007
A new kinorhynch genus from the Antarctic deep sea and a new species of Cephalorhyncha from Hawaii (Kinorhyncha: Cyclorhagida: Echinoderidae)Download PDFAbstract
A new species of a new kinorhynch genus with affinities to the Echinoderidae and a new species of Cephalorhyncha are described. Polacanthoderes martinezi gen. et sp. nov. was collected during the German ANDEEP-1 cruise at 2290m depth north of the South Shetland Islands in the Southern Atlantic Ocean, approximately 170km north of the Antarctic Peninsula. Polacanthoderes is characterized by the presence of a first trunk segment consisting of a complete cuticular ring, and by each of the following ten segments consisting of one tergal and two sternal plates. Cuticular hairs and perforation sites are absent, but spines are present in middorsal, subdorsal, laterodorsal, midlateral, lateral accessory, lateroventral, ventrolateral and ventromedial series on segments 4–10. The ventral side of segment 1 has a very strong and conspicuous pectinate fringe, whereas fringes are indistinct or absent on posterior segment margins of the following segments. Due to segment 1 being composed of a closed ring and the following segments of a tergal and two sternal plates, as well as to the presence of aligned middorsal spines and lateral terminal spines but absence of a midterminal spine, Polacanthoderes is assigned to the family Echinoderidae.Cephalorhyncha liticola sp. nov. was collected in the intertidal zone of a high energy beach on the northeast coast of Oahu, Hawaii. The species is characterized by the sternal plate of segment 2 being incompletely separated anteriorly by a midventral fissure. Middorsal spines are present on segments 4–8, ventrolateral spines on segment 2, lateroventral spines on segments 5–9, lateral accessory spines on segment 8, and laterodorsal spines on segment 10. In addition, there are special sensory spots with conspicuous marginal cuticular hairs on segments 1–3, and very long pectinate fringes on the sternal plates of segments 3–10. The partly subdivided sternal plates on segment 2 show the species to belong to the echinoderid genus Cephalorhyncha.
Received: 25 April 2007 / Accepted: 24 September 2007
Undersized and underestimated: 3D visualization of the Mediterranean interstitial acochlidian gastropod Pontohedyle milaschewitchii (Kowalevsky, 1901)Download PDFAbstract
Pontohedyle milaschewitchii (Kowalevsky, 1901) is one of the most common mesopsammic opisthobranchs in the Mediterranean and Black Seas and has been considered as a comparably well-described acochlidian species. However, data on its complex internal anatomy were fragmentary and little detailed due to inadequate methodology available, and contradictory between different sources. The present study redescribes all major organ systems of P. milaschewitchii in full detail by three-dimensional reconstruction from serial semithin sections using AMIRA software. The prepharyngeal central nervous system (cns) of P. milaschewitchii is highly concentrated and shows a euthyneurous and epiathroid condition. Contrary to earlier reports, the cerebral and pleural ganglia are not fused. Aggregations of precerebral accessory ganglia can be grouped into three complexes supplied by distinct cerebral nerves. Rhinophoral ganglia with thin, double cerebro-rhinophoral connectives are described for the first time in acochlidians. A Hancock's organ is present in the form of a conspicuous, curved fold in the epidermis posterior to the oral tentacles. Cerebral nervous features and sensory structures are discussed comparatively. Our study confirms P. milaschewitchii as having the male genital opening in an unusual position above the mouth. Homology of the ciliated vas deferens of the gonochoristic and aphallic P. milaschewitchii with that of hermaphroditic acochlidian species with cephalic male genitals is discussed. The radula formula of P. milaschewitchii is 41–54×1-1-1, i.e. the single lateral teeth are broad and, contrary to previous descriptions, undivided. SEM examination of the body wall of entire specimens revealed a special and constant ciliary pattern. Providing a novel additional set of characters for taxonomic and phylogenetic purposes, external SEM examination is suggested as the standard method for describing acochlidian species in the future.
Received: 01 June 2007 / Accepted: 12 September 2007
Phylogeny of South American Pogonieae (Orchidaceae, Vanilloideae) based on sequences of nuclear ribosomal (ITS) and chloroplast (psaB, rbcL, rps16, and trnL-F) DNA, with emphasis on Cleistes and discussion of biogeographic implicationsDownload PDFAbstract
Tribe Pogonieae (Orchidaceae), as currently known, comprises five genera distributed from South to North America and Eastern Asia. Phylogenetic inferences within Cleistes and among genera of tribe Pogonieae were made based on nrDNA (ITS) and cpDNA (trnL-F, rps16, rbcL, and psaB) sequence data and maximum parsimony. Eighteen species of Cleistes, members of all other genera of Pogonieae, and outgroups were sampled. Analyses based on individual DNA regions provided similar topologies. All evidence indicates that Cleistes is paraphyletic. The North American C. divaricata and C. bifaria are more closely related to the temperate genera Isotria and Pogonia than to their Central and South American congeners, the latter constituting a monophyletic group characterized by the production of nectar as reward, tuberous roots, and their distribution in Central and South America. The Amazonian Duckeella is sister to the remainder of Pogonieae. Taxonomic and biogeographic implications are discussed, and morphological synapomorphies are given for clades obtained in the inferred molecular phylogeny.
Received: 29 May 2006 / Accepted: 11 September 2006
Diversity and distributions of the submarine-cave Neritiliidae in the Indo-Pacific (Gastropoda: Neritimorpha)Download PDFAbstract
Sediment samples from approximately 100 submarine caves on tropical islands in the Indian, Pacific and Atlantic oceans were examined to elucidate the global diversity and distribution of obligate submarine-cave snails of the family Neritiliidae. Shells accumulated from the Indo-West Pacific samples comprise five genera and nine species of extant neritiliids, whereas there were none from the Atlantic. Four new genera and four new species are herewith described: Laddia lamellata, Micronerita pulchella, Teinostomops singularis and Siaesella fragilis; previously known species include Laddia traceyi comb. n., Pisulina adamsiana, Pisulina biplicata, Pisulina maxima and Pisulina tenuis. Of these nine species, seven have wide, largely overlapping distributions; species richness is highest in and around the Indonesian and Philippine region, as in countless cases of shallow-water fishes, corals, echinoderms, bivalves and other gastropods. Examination of protoconch morphology revealed five species with a fairly long, planktotrophic larval period and four species with non-planktotrophic early development. No clear relationship was found between distribution range and dispersal capability deduced from the developmental mode, whereas the non-planktotrophs had higher levels of geographic differentiation in shell morphology. Fossil assemblages from cryptic environments suggest a Tertiary origin of the submarine-cave Neritiliidae. The oldest extant genus, Laddia, appeared in the Miocene, while two other Tertiary genera, Bourdieria and Pisulinella, have become extinct. The submarine-cave Neritiliidae thus do not seem to have remained in the same cave systems or the same local regions for millions of years, but seem to be relatively young, active colonizers of both continental and oceanic islands, having repeatedly expanded their distributions over the Indo-West Pacific. Despite the fact that they are undoubtedly restricted to caves and similar cryptic habitats, transoceanic dispersal appears to have played as important a role in forming present distributions as did tectonic events, in species with or without a planktotrophic larval period.
Received: 23 October 2006 / Accepted: 31 May 2007
Molecular phylogeography of the viperine snake Natrix maura (Serpentes: Colubridae): Evidence for strong intraspecific differentiationDownload PDFAbstract
The molecular phylogeography of the viperine snake, Natrix maura (Linnaeus, 1758), was investigated using complete sequences of the mitochondrial cytochrome b gene and genomic ISSR-PCR fingerprinting. In a total of 120 samples, 44 unique cytochrome b haplotypes were found which defined three major genetic lineages associated with samples from Morocco, Tunisia and Europe, respectively. The same lineages were supported by nuclear data. A possible fourth lineage exists in southern Spain. Genetic distances of cytochrome b sequences between the three main lineages were in the range of 3.9–5.6%, suggesting independent evolution since the early Pliocene. Distinction of the three major lineages at the subspecies or species level is discussed to account taxonomically for the high intraspecific variation in the viperine snake. A more detailed analysis of the European samples based on genetic diversity indices and a network reconstruction suggests a complex Pleistocene history for the viperine snake in Europe. Clear differentiation was found between populations south and north of the central Iberian mountain ranges, suggesting Pleistocene glacial refugia both in the southern and northern Iberian peninsula. In the south, genetic diversity was associated with the main river valleys, whereas northern haplotypes were more broadly distributed, indicating gene flow or postglacial range expansions. Unexpectedly high levels of genetic variation in southeastern France and northwestern Italy would be compatible with the hypothesis of a glacial refugium north of the Pyrenees or in Italy. However, due to the dependence of N. maura on warm climates, the assumption of a northern refugium seems unwarranted. We believe that further sampling in northern Spain is likely to reveal genetically diverse populations which could have served as sources for postglacial recolonization of France and Italy.
Received: 14 February 2007 / Accepted: 16 October 2007
Taxonomy and ribosomal DNA-based phylogeny of the Electra crustulenta species group (Bryozoa: Cheilostomata) with revision of Borg's varieties and description of Electra moskvikvendi sp. nov. from the Western Baltic SeaDownload PDFAbstract
In 1931, Borg distinguished five “varieties” as morphologically differing from what he perceived as the ‘typical form’ of Electra crustulenta (Pallas, 1766). Taxonomic status has not been resolved for all of those morphotypes. One of them was recently recognized as a separate species, E. arctica; two are considered as species in other genera. In the present study the remaining three of Borg's subdivisions, “forma typica”, “var. baltica” and “var. fossaria”, were analyzed to evaluate their status and reconstruct phylogenetic relationships within the whole species group based on ribosomal 16S mtDNA and 18S nDNA. All known E. crustulenta-like species and forms with unresolved status were included: E. crustulenta (including “f. typica”, “var. baltica” and “var. fossaria”), E. arctica, E. korobokkura, and Electra moskvikvendi sp. nov. A well-supported phylogeny fully concordant for both genetic markers was obtained with maximum parsimony, neighbor-joining, maximum likelihood, and Bayesian methods. Statistical parsimony was applied to the 16S dataset. Only four species were revealed regardless of the method or gene fragment, with E. crustulenta as a single species. There was no evident correlation between the morphotypes “f. typica”, “var. baltica” and “var. fossaria” and haplogroups found in E. crustulenta populations. The E. crustulenta species group consisted of two subgroups: E. crustulenta–E. korobokkura and E. moskvikvendi–E. arctica. Divergence of the mitochondrial lineages within the group was dated using a Bayesian relaxed-clock approach. Most probably the diversification of the lineages examined started in the Early Miocene. Electra arctica and E. moskvikvendi sp. nov. are two young species, having diverged during the Pliocene–Pleistocene. The new species described here was found in the Western Baltic Sea, Kiel Bay. An identification key for the E. crustulenta species group is given, based on morphology, morphometry, and geographical and ecological ranges. Additionally, reference sequences of 16S and 18S DNA for each species, which can be used for DNA-based barcoding, have been published.
Received: 08 March 2006 / Accepted: 14 August 2006
Larval and molecular characters help to solve phylogenetic puzzles in the highly diverse dragonfly family Libellulidae (Insecta: Odonata: Anisoptera): The Tetrathemistinae are a polyphyletic groupDownload PDFAbstract
The systematics of the dragonfly family Libellulidae remains an unsolved puzzle. The classification into subfamilies relies primarily on wing venational characters, as is the case for most systematic hypotheses on dragonflies. In this study, we show that the discovery of unknown libellulid larvae can change tremendously our views on phylogenetic relationships. The larvae of the genera Micromacromia Karsch, 1889 and Allorhizucha Karsch, 1889 are described and illustrated. They are briefly compared with the larva of Neodythemis Karsch, 1889. The larvae of A. klingi Karsch, 1889 and N. africana Fraser, 1954 are extremely similar. The larva of M. camerunica Karsch, 1889 displays well developed dorsal hooks on abdominal segments 4–8, which distinguishes it from other closely allied genera. Micromacromia, Allorhizucha and Neodythemis are traditionally placed within the Tetrathemistinae, but their larvae strongly resemble those in the subfamily Libellulinae. Larval morphological studies and a molecular analysis based on mitochondrial SSU, LSU and tRNA valine imply that Micromacromia, Allorhizucha and Neodythemis have to be placed in the subfamily Libellulinae. Consequently, the subfamily Tetrathemistinae becomes a polyphyletic group. Our analysis suggests that imaginal characters, and in particular wing venation, are much more often prone to homoplasious evolution than previously anticipated. Taxonomic or systematic works predominantly based on wing venation might be in need of substantial revision, at least within this dragonfly family, presumably even in the whole suborder Anisoptera, based on independent character sets like larval and molecular data.
Received: 31 January 2006 / Published online: 19 August 2006
Forum: Hierarchy and clade definitions in Phylogenetic taxonomyDownload PDF
Received: 14 February 2007 / Accepted: 18 September 2007
ITS2 secondary structure and phylogeny of cyst-forming nematodes of the genus Heterodera (Tylenchida: Heteroderidae)Download PDFAbstract
The internal transcribed spacer 2 (ITS2) of the ribosomal RNA gene is a double-edged tool for eukaryote evolutionary comparison. In this paper, we re-evaluate the putative ITS2 secondary structures proposed for 29 species of cyst-forming nematodes in the genus Heterodera and present optimized variants. The models are organized in four main helices emerging from a central core. Helix III is always the longest and has two branches exhibited as a Y-shaped structure near the apex. In most species, helices III and IV have merged to form a segment of the central core. Two conservative motifs, GAUCR and UURC, were found in helices II and III, respectively. Using the MARNA program taking into consideration both the primary sequence and the secondary structure, we generated an optimal alignment for Heterodera sequences. The alignment was analyzed by Bayesian inference under a general-time-reversible model and the complex models, and by a maximum parsimony approach using original data and sequence data converted according to secondary-structure information. The consensus ITS2 secondary structure model for Heteroderidae can serve as a useful guide for reconstruction of optimal alignment and can be used as an additional source of data incorporating structural parameters of molecules for the study of nematode phylogeny. Application of the secondary ITS2 structure data allows a more resolved and realistic picture of relationships within Heteroderidae.
Received: 27 March 2007 / Accepted: 03 June 2007
New species and new records of the fern genus Terpsichore (Polypodiopsida: Polypodiaceae) from BoliviaDownload PDFAbstract
We describe five new species, report a new record for the genus Terpsichore, and provide a key to the Bolivian species.
Received: 29 October 2007 / Accepted: 14 March 2008
Ancient or recent? Insights into the temporal evolution of the BruniaceaeDownload PDFAbstract
The Bruniaceae are a South African plant family endemic to the Cape Floristic Region with one geographic outlier (Raspalia trigyna) in the Natal Province. Recent molecular phylogenetic analyses have cast new light upon inter- and intra-generic relationships within the family. The present work uses those data to gain insights into the temporal evolution of Bruniaceae by inferring a molecular clock. For calibration, the inferred age of Berzelia cordifolia (3–5My) was used, based on its distribution restricted to the geologically young limestone area around Bredasdorp. The results are consistent with the purported Cretaceous age of the family (‘palaeoendemics’), but also suggest that most extant species are relatively young. The major diversification of the family may have happened within relatively recent times (between 18 and 3Mya), simultaneously with the establishment of the present Mediterranean climate in their environment. The disjunct distribution of Raspalia trigyna may be attributable to migration over sandstone exposed during a brief marine regression of the Indian Ocean at the Miocene–Pliocene boundary.
Received: 10 May 2006 / Accepted: 01 November 2006
Amazonian lowland, white sand areas as ancestral regions for South American biodiversity: Biogeographic and phylogenetic patterns in Potalia (Angiospermae: Gentianaceae)Download PDFAbstract
Present-day white sand areas in South America are thought to be relictual areas of earlier, widespread habitats now covered by more recent sediments mainly from the Andean orogeny. These ancient, nutrient-poor areas have been suggested to be possible ancestral regions for neotropical plant diversity. Members of the genus Potalia of the Gentianaceae grow in the New World tropics from Costa Rica in the north to southern Bolivia. Until recently, only one Potalia species was accepted, but a new revision identifies eight others. Three species are endemic to lowland, white sand areas in the Amazon and Orinoco basins and share morphological characteristics with Anthocleista, the African – Malagasy sister group to Potalia. To resolve phylogenetic and biogeographic patterns in Potalia, morphological characters and sequences of the internal transcribed spacer (ITS) and the 5S non-transcribed spacer (5S-NTS) of the ribosomal nuclear DNA were collected and used for phylogenetic reconstruction using Bayesian and parsimony-based methods. Potalia species restricted to ancient, nutrient-poor white sand areas of the Amazon Basin and Guayana Shield were placed basal to other Potalia taxa from finer, lateritic, and younger soils, further suggesting that lowland white sand areas may be ancestral seats of neotropical diversity.