Received: 30 September 2005 / Accepted: 08 February 2006
Evolution of flower morphology, pollen dimorphism, and nectar composition in Arcytophyllum, a distylous genus of RubiaceaeDownload PDFAbstract
A phylogenetic study of Arcytophyllum based on ITS was conducted and compared with an earlier study based on cpDNA. The position of the widespread A. thymifolium as sister to all other species was confirmed and several well-supported clades could be retrieved. The Central American A. lavarum is well embedded between exclusively or predominantly South American species. To understand the expression of heterostyly in the genus, we analyzed inter- and intraspecific variation in floral morphology, nectar, pollen–ovule (P/O) ratio and seed set of ten species in 11 populations. Stigma and anther levels differed significantly between the morphs in the species/populations investigated, except for A. filiforme, in which anther levels did not differ significantly between the two morphs. Different expressions of heterostyly in Arcytophyllum seem independent of phylogenetic relationships. Nectar sugar composition was similar between the morphs. Nectar of most species presented a larger proportion of hexoses than of sucrose; only the most derived species, A. macbridei and A. vernicosum, have higher sucrose proportions. There is a significant positive correlation between corolla tube length and the proportion of sucrose. Pollen dimorphism, with regard to both number (long-styled>short-styled) and size (short-styled>long-styled), was observed in all taxa investigated except A. filiforme. According to the P/O ratios, the breeding systems range from facultative autogamy to facultative xenogamy. The lowest P/O ratios were found in A. filiforme, and the highest in A. rivetii. Hymenoptera, Diptera and Coleoptera were observed as flower visitors. Seed production did not differ significantly between the morphs in eight of the 11 species/populations investigated. There is, however, a tendency in all species/populations (except in A. macbridei Peru) for the short-styled morph to have a higher percentage of seeds per ovule, indicating that the short-styled morphs display higher female reproductive success.
Received: 22 June 2005 / Accepted: 25 September 2006
A PCR method for detection of plant meals from the guts of insectsDownload PDFAbstract
The feeding behaviour of insects is a difficult ecological interaction to study. To date, entomologists have used biochemical and molecular techniques to identify the meals of predatory insects. We present here a molecular approach to identifying the DNA of plant species in the insect gut using the ribulose bisphosphate carboxylase gene large subunit (rbcL). A reference collection of 23 plant species from the southern Jordan Valley, Israel, was genetically characterized and employed. Insects belonging to eight different families were collected in the field along with the plants upon which they were found. After collection and prior to analysis, these insects were isolated on the plants they were found upon in the laboratory. This was to ensure that the insects had only one plant meal in their gut, as multiple plant meals would require additional techniques like cloning. A blind study was performed, genetically confirming plant DNA to species level from the processed gut contents of the insects. All reference plant species could be differentiated using a 157bp long fragment of the rbcL gene. Plant DNA was identifiable, and the meal of the respective insect was accurately determined in each case. Analyses using experimentally fed crickets, Gryllodes hebraeus, determined that plant DNA was still detectable by PCR up to 12h post-ingestion. This research proposes the application of molecular techniques for the identification of herbivorous insect feeding behaviour to increase understanding of plant–insect interactions.
Received: 03 May 2005 / Accepted: 06 July 2006
Micropacteridae, a new family of Remipedia (Crustacea) from the Turks and Caicos IslandsDownload PDFAbstract
Recent diving explorations of anchialine caves on the Turks and Caicos Islands yielded a rather small and slender new species of Remipedia. Micropacter yagerae n. gen., n. sp. is distinguished from all other species of nectiopod remipedes by a number of autapomorphic characters, including an oval body terminus with fused segments, unequal pairs of terminal claws on maxilla and maxilliped, an almost complete reduction of sternal bars and pleurotergites, molar processes with relatively few, but strong spines, and frontal filaments with bifurcate processes. Based on the unique combination of derived and primitive characters, we propose to erect a new family, Micropacteridae, for this new species and genus of Remipedia. Taxonomic diagnoses for the class Remipedia, order Nectiopoda (emended due to discovery that the maxilliped is 9-segmented), and for the families Speleonectidae and Godzilliidae are presented and discussed.
Received: 07 September 2004 / Accepted: 21 November 2006
Protists – A textbook example for a paraphyletic taxonDownload PDFAbstract
Protists constitute a paraphyletic taxon since the latter is based on the plesiomorphic character of unicellularity and does not contain all descendants of the stem species. Multicellularity evolved several times independently in metazoans, higher fungi, heterokonts, red and green algae. Various hypotheses have been developed on the evolution and nature of the eukaryotic cell, considering the accumulating data on the chimeric nature of the eukaryote genome. Subsequent evolution of the protists was further complicated by primary, secondary, and even tertiary intertaxonic recombinations. However, multi-gene sequence comparisons and structural data point to a managable number of such events. Several putative monophyletic lineages and a gross picture of eukaryote phylogeny are emerging on the basis of those data. The Chromalveolata comprise Chromista and Alveolata (Dinoflagellata, Apicomplexa, Ciliophora, Perkinsozoa, and Haplospora). Major lineages of the former ‘amoebae’ group within the Heterolobosa, Cercozoa, and Amoebozoa. Cercozoa, including filose testate amoebae, chlorarachnids, and plasmodiophoreans seem to be affiliated with foraminiferans. Amoebozoa consistently form the sister group of the Opisthokonta (including fungi, and with choanoflagellates as sister group of metazoans). A clade of ‘plants’ comprises glaucocystophytes, red algae, green algae, and land vascular plants. The controversial debate on the root of the eukaryote tree has been accelerated by the interpretation of gene fusions as apomorphic characters. In the more traditional view, based on sequence comparisons using archaebacteria as outgroup representatives, parabasaleans and diplomonads branch off first, rendering the biflagellate eukaryotes paraphyletic. In sharp contrast, the root is placed between Bikonta and Opisthokonta plus Amoebozoa on the argument of a single enzyme gene fusion which is postulated to have occurred in the stem species of the Bikonta, and of a double enzyme gene fusion weighed as a synapomorphy of the Opisthokonta and Amoebozoa. We conclude that the paraphyletic taxon ‘protists’ may be maintained for practical reasons. However, introduction of new, clearly recognizable paraphyletic taxa should be avoided.
Received: 27 April 2005 / Accepted: 10 April 2006
A new species of Liropus (Crustacea, Amphipoda, Caprellidae) from Le Danois bank (southern Bay of Biscay)Download PDFAbstract
A new species of the genus Liropus (Crustacea, Amphipoda, Caprellidae) is described based on specimens collected from Le Danois bank (‘El Cachucho’ fishing grounds), Bay of Biscay. Liropus cachuchoensis n. sp. can be distinguished from all its congeners mainly by the absence of eyes and by the presence of a dorsal projection proximally on pereonites 3, 4 and 5 in males, on 3 and 5 in females. The new species has been found living on muddy bottoms on the southern flank of the bank and adjacent continental slope, between 619 and 1062m depth, with a maximum abundance (56.1ind./100m2) recorded at 1044–1062m. Morphological comparisons among the world's members of Liropus, a key to species, and data on their distribution are presented.
Received: 29 April 2005 / Accepted: 18 November 2005
Description of new taxa of Halenia Borkh. (Gentianaceae) from Colombia and Venezuela with significance for testing a key innovation hypothesisDownload PDFAbstract
As a result of an ongoing complete taxonomic revision of Halenia (Gentianaceae), the new taxa Halenia perijana K.B. Hagen and H. major subsp. meridensis K.B. Hagen are described from Colombia and Venezuela, respectively. Flower morphology suggests that both taxa belong to the Halenia viridis group. H. perijana is vegetatively well separated from its probable closest relatives, and the only member of Halenia from a small and rather isolated mountain range. The new subspecies meridensis has small remnants of nectary spurs, and probably links the unspurred viridis group to its prominently spurred Central American sister group. Previous molecular clock approaches showed that the viridis group arrived in South America approximately at the same time as the weddelliana group, the distantly related second major South American group, which contains species with prominent spurs. Based on the new extensive knowledge of all species, the distribution patterns of both groups in Colombia and Venezuela are compared. The existence of marked differences—weddelliana group species grow in sympatry more often than species of the viridis group—is consistent with a key innovation effect of the presence/absence of nectary spurs, i.e., the reduction of pollinator overlap mediated by the presence of nectary spurs may allow sympatric speciation or remigration after a shorter phase of allopatric differentiation. However, this new evidence is relatively weak due to lack of statistical support and several other unresolved problems.
Forum: Abstracts of the 9th Annual Congress of the ‘‘Gesellschaft für Biologische Systematik’’ (GfBS)Download PDF
Received: 22 February 2006 / Accepted: 04 May 2006
Proventricular structure in the bee tribe Augochlorini (Hymenoptera: Halictidae)Download PDFAbstract
Characters of the digestive tract have received little attention in modern phylogenetic analyses regarding relationships among bees, in part because studies on the internal morphology of bees generally concentrate on physiological and behavioural aspects. This paper presents a comparative study of the proventricular structure, analysed with scanning electronic microscopy, in bees of the tribe Augochlorini. Eleven species of Augochlorini were analysed as the ingroup, versus one each of Halictini and Caenohalictini, and two of Crabronidae as outgroups. The presence of a long columnar proventricular fold is an apomorphy for Augochlorini, whereas a proventricular fold with a keel-shaped structure at the moving lip level is an apomorphy for Augochlorina. Together these data corroborate the monophyly of Augochlorini and Augochlorina, respectively.
Received: 30 November 2005 / Accepted: 16 March 2006
A plywood structure in the shell of fossil and living soft-shelled turtles (Trionychidae) and its evolutionary implicationsDownload PDFAbstract
The shell of soft-shelled turtles (Cryptodira: Trionychidae) can be characterised by a flexible bridge region, the loss of peripherals and a flattened carapace that is covered not with keratinous shields but with a leathery dermis. Here, we give a detailed description of the bone histology of this natural body armour that is unique not only among turtles but also among all known vertebrates. The flat bone elements have a sandwich-like morphology, with an internal and external compact bone layer framing inner cancellous bone. The external cortex is subdivided into two separate zones. The outer zone of the external cortex, which encompasses the ornamentation pattern typical for trionychid turtle shell bones, is comprised of lamellar bone. Similarly, the whole of the internal cortex is comprised of lamellar bone. The inner zone of the external cortex, however, consists of a highly ordered, plywood-like arrangement of structural collagen fibre bundles within the bone and skin of the shell. The orientation of the collagenous fibres also prescribes the orientation of the mineral phase of the bone, the hydroxyl-apatite crystallites. Strikingly, this peculiar fibre bundle arrangement strongly resembles artificial reinforced fibre-strengthened polymeric materials that combine superior mechanical strength with low weight. We hypothesise that the evolutionary success of soft-shelled turtles is tied to this plywood-like structure of the skin and bone. It may have been the key adaptation that allowed trionychids to greatly reduce and flatten their protective shell, resulting in decreased mineral needs for hard tissues, improved camouflage and hunting performance, biomechanical stability of the shell, as well as overall increased agility and short-term swimming boosts. Significantly, it also may have enabled more efficient cutaneous breathing while still retaining effective armour in both the fossil and Recent trionychid turtles.
Received: 13 June 2006 / Accepted: 10 August 2006
Phylogeny of basal eudicots: Insights from non-coding and rapidly evolving DNADownload PDFAbstract
Sequence data of the trnL group I intron, the petD group II intron, the trnL-F and petB-D spacers, and the rapidly evolving matK gene were analysed from all families of the basal eudicot grade and from representatives of 19 core eudicot orders. The dataset comprised 5654 positions of aligned sequence plus a matrix of 1087 binary indel characters. Mutational hotspots correspond in number and extension to hotspots already known from basal angiosperms and, with respect to secondary structure, are generally located in terminal parts of stem-loop regions. Parsimony, Bayesian, and likelihood analyses depict Ranunculales as sister to all remaining eudicots with maximum support. The branching order in the basal eudicot grade is further resolved as Sabiales, Proteales, Trochodendrales, and Buxales. Nearly all of the backbone nodes gain high confidence, except for the node showing Proteales diverging before Trochodendrales, which is only moderately supported (83% JK). In Ranunculales, the woody Eupteleaceae are first-branching, with Papaveraceae plus Fumariaceae coming next. Within Proteales, Nelumbo is clearly resolved as sister to a Platanaceae–Proteaceae clade. Gunnerales are found as the first branch in core eudicots, with maximum support in the combined analysis. This node is also resolved with matK alone, but unsupported. It appears that the combined analysis of sequence data from rapidly evolving and non-coding genomic regions leads to significantly improved statistical support values in comparison to earlier studies of basal eudicots using multiple conserved genes.See also Electronic Supplement at doi:10.1016/j.ode.2006.08.001
Received: 02 June 2005 / Accepted: 19 August 2006
Rhopalophthalmus tartessicus sp. nov. (Crustacea: Mysidacea), a new mysid species from the Guadalquivir estuary (SW Spain)Download PDFAbstract
The first representative of the genus Rhopalophthalmus in European waters, Rhopalophthalmus tartessicus sp. nov., is described from specimens sampled in the Guadalquivir estuary (southwestern Spain). At first identified as the Algerian species Rhopalophthalmus mediterraneus Nouvel, 1960, the new mysid species can be distinguished from its closest relative by its higher number of articles on the carpopropodus of the third to seventh thoracic endopods, by the well hook-shaped eighth thoracic endopod of the male, by the slender eighth thoracic endopod of the female, and by the smaller antennal scale and telson. Its geographical distribution appears restricted to estuarine habitats in southwestern Spain. Its swimming behaviour, with the ventral side facing upwards, is unusual in mysids. An updated identification key for the 19 known species in the genus, including information on the respective geographical distribution and habitat, is presented.
Received: 29 July 2005 / Accepted: 01 February 2006
The morphology and independent origin of ovoviviparity in Tiphobia and Lavigeria (Caenogastropoda: Cerithioidea: Paludomidae) from Lake TanganyikaDownload PDFAbstract
To better understand the diversification of the endemic thalassoid (i.e. marine-like) cerithioidean gastropods of Lake Tanganyika, as well as the origin and significance of brooding among lake species, we here redescribe the anatomy and ontogeny of the ovoviviparous Tiphobia horei from Lake Tanganyika and compare it to that of Lavigeria sp. A, representing another ovoviviparous lake clade that has acquired a uterine brood pouch independently. Within the phylogenetic framework provided by recent molecular analyses, the distant relation of these two taxa is corroborated by many external and internal anatomical differences. Comparison of the brood pouches demonstrates that they each bear unique features consistent with their independent modification for brooding. Despite representing functionally analogous structures, they also share several similarities in organization likely representing symplesiomorphies of the Lake Tanganyika species flock. The ontogeny is characterized by the presence of a velum and by delayed calcification producing a characteristically wrinkled embryonic cap. Comparison with other brooding cerithioideans reveals that T. horei and Lavigeria sp. A retain many more embryos than other freshwater cerithioideans of comparable size with a uterine brood pouch, possibly facilitated by the presence of longitudinal lamellae. Compartmentalization of the oviduct and delayed calcification is strongly linked to the brooding of embryos.
Received: 06 January 2006 / Accepted: 20 April 2006
Molecular, biogeographical and phenological evidence for the existence of three western European sibling species in the Colletes succinctus group (Hymenoptera: Apidae)Download PDFAbstract
This paper examines a cryptic species complex comprising three nominal bee species: Colletes halophilus, Colletes hederae, and Colletes succinctus. Multiple individuals of each were sequenced for four gene fragments: mitochondrial cytochrome oxidase 1 (CO-1), internal transcribed spacer 2 (ITS-2) and flanking regions, elongation factor 1 alpha (EF-1α), and 28S. In addition, the distribution patterns and phenology of all species were examined. Fixed substitutions distinguishing the three species are present in EF-1α and ITS-2. Their distribution patterns differ clearly: Colletes halophilus is endemic to coastal habitats of the southern North Sea and the English Channel; Colletes hederae occurs from Slovenia in the southeast to southern England in the northwest; the range of Colletes succinctus covers most of Europe and reaches western Kazakhstan. Where the three species occur jointly in western Europe, their flight activities differ significantly. The genetic distinctions and the differences in distribution, phenology and flower specialisation clearly support their status as distinct species.
Received: 06 February 2006 / Accepted: 02 June 2006
Morphometrics and SEM analysis of the species pair Lithobius mutabilis L. Koch, 1862 and L. glacialis Verhoeff, 1937 (Chilopoda: Lithobiomorpha)Download PDFAbstract
The sets of morphological characters of two nominal species in the genus Lithobius Leach, 1814, Lithobius mutabilis L. Koch, 1862 and Lithobius glacialis Verhoeff, 1937, were studied in order to test specific dissimilarity. Morphometrics were examined and analysed statistically. In addition, a comparative SEM analysis of external characters was made. Morphometrically significant differences between the species were found concerning body length, the width ratio of the head to the 5th tergite, the number of antennal articles, and the length/width proportions of certain articles (e.g. the femur) of the 15th legs of males. Because of these and several additional differences, such as in tergite surface structure, modifications to the 15th legs of males, the structure of the female gonopod claws, and between the ecological profiles, L. glacialis, which is found in the high Alps at altitudes above timberline (1300m), can be distinguished clearly from L. mutabilis. This study demonstrates another example for a cryptic species pair, a common phenomenon between lowland and alpine populations of small invertebrates. The combination of morphometrics and SEM offers a powerful methodology for resolving previously uncertain questions in the species-level taxonomy of centipedes.
Received: 26 October 2005 / Accepted: 30 June 2006
Taxonomic re-evaluation of the Taiwanese montane earthworm Amynthas wulinensis Tsai, Shen & Tsai, 2001 (Oligochaeta: Megascolecidae): Polytypic species or species complex?Download PDFAbstract
Body size and colouration are two characters commonly used in the taxonomy of many animal taxa. However, they are seldom used by earthworm taxonomists because they are subject to environmental influences and tend to vary intraspecifically. In the present study, DNA sequences of the mitochondrial COI gene are used to evaluate whether specimens of the megascolecid earthworm Amynthas wulinensis Tsai, Shen & Tsai, 2001 that differ in body size and/or colouration belong to different genetic lineages. Phylogenetic analyses and morphological comparisons indicate that A. wulinensis in the previous broad sense is a species complex composed of three species differing in body size, colouration, and genital markings. Consequently, two new species, Amynthas lini and Amynthas meishanensis, are described. Taxonomic affinities of the A. wulinensis species complex are discussed, as is the feasibility of using body size and colouration in earthworm taxonomy.
Received: 13 February 2006 / Accepted: 16 March 2006
High phylogenetic diversity of Flavobacterium spp. isolated from a hardwater creek, Harz Mountains, GermanyDownload PDFAbstract
Of 930 strains isolated on nutrient-poor media from water samples taken at four sites along a 370-m-long stretch of a hardwater creek, Westerhöfer Bach, Harz Mountains, Germany, more than half had swarming capacity, many of which with slimy appearance. MALDI-TOF spectroscopic analysis of 60 randomly picked isolates grouped about 45% of them in different orders of Proteobacteria, while about 55% clustered with a representative of the genus Flavobacterium. The latter affiliation was supported by positive flexirubin reaction and fatty acid profiles performed on a subset of these isolates. Partial 16S rRNA gene sequence analysis of more than 100 swarming strains also supported the protein-based analysis, and suggested high phylogenetic diversity of the flavobacterial isolates at the intrageneric level. Phylogenetic analysis of almost complete gene sequences obtained for 41 strains and type strains of Flavobacterium species refined the phylogeny, allowing the conclusions that only some isolates are members of described species, and that the phylogenetic depth of the other lineages is indicative of the presence of about 20 novel Flavobacterium species, providing support by the polyphasic approach to systematics. The phylogenetic breadth and depth of diversity of Flavobacterium spp. in this creek are very similar to those in epilithon samples from the nutrient-rich River Taff in Cardiff (O’Sullivan, L.A., Rinna, J., Humphreys, G., Weightman, A.J., Fry, J.C., 2006. Culturable phylogenetic diversity of the phylum ‘Bacteroidetes’ from river epilithon and coastal water and description of novel members of the family Flavobacteriaceae: Epilithonimonas tenax gen. nov., sp. nov. and Persicivirga xylanidelens gen. nov., sp. nov. Int. J. Syst. Evol. Microbiol. 56, 169–180.), prompting speculation about the rationale for this finding.
Received: 07 December 2005 / Accepted: 28 June 2006
Head anatomy of Xyelidae (Hexapoda: Hymenoptera) and phylogenetic implicationsDownload PDFAbstract
External and internal head structures of Macroxyela ferruginea (Say) and Xyela julii (Brébisson) were examined. A detailed description is provided for Macroxyela. The results are compared to the conditions found in other basal hymenopterans and representatives of other groups of endopterygote insects. Hitherto unnoticed autapomorphies of Hymenoptera are the concavity of the posterior head capsule, the very dense, regular vestiture of hairs, the collar-like, strongly developed posterior tentorium, and a large epipharyngopharyngeal lobe. Microphagous habits and associated features (asymmetric mandibular molae, epipharyngeal brush, infrabuccal pouch) are possibly groundplan features of Hymenoptera and Endopterygota. A switch to more or less liquefied food took place early in the evolution of Hymenoptera. The sitophore plate and a constricted, elongated prepharyngeal tube are likely synapomorphies of Hymenoptera and Mecopterida. Monophyly of Hymenoptera excluding Xyelidae is supported by the reduction of the mandibular molae and epipharyngeal brush. These changes are likely related to modified feeding habits. Widely separated mandibular bases, the loss of the median labral retractor (parallel loss in Xyelidae), and the presence of a hypostomal bridge are potential apomorphies of Hymenoptera excluding Xyelidae and Tenthredinoidea. Monophyly of Xyelinae and Macroxyelinae, respectively, is well supported by the results of our study. There is conflicting evidence as to whether Xyelidae is monophyletic. The presence of a subdivided galea is a putative autapomorphy of the family. The presence of unsclerotised paraglossae with dense fringes of thin hairs and the presence of a muscle connecting the anterior tentorial arm with the posterior edge of the sitophore plate are features shared by Xyelinae and members of non-xyelid families.
Received: 29 September 2006 / Accepted: 13 April 2007
Questa (Annelida, Polychaeta, Orbiniidae) from Pacific regions — new species and reassessment of the genus PeriquestaDownload PDFAbstract
On the basis of new material from various Pacific regions we critically evaluate the characters for the taxonomy of the genus Questa and the former Questidae, a taxon now concluded to be a lineage within the family Orbiniidae. Two new species, Questa retrospermatica sp. n. from Hawaii (with similar forms also from New Caledonia and China), and Questa fijiensis sp. n. from Fiji, are described, and the morphological character patterns and phylogeny of the genus are revisited on the basis of a cladistic analysis. The finding of Hawaiian material of a new species, Levinsenia hawaiiensis sp. n., similar to Periquesta canariensis Brito & Nunez, 2002 (=Levinsenia canariensis comb. n.), challenges the view that Periquesta Brito & Nunez, 2002 is closely related to Questa; rather, it belongs to Paraonidae as a junior synonym of Levinsenia Mesnil, 1897.
Received: 28 September 2005 / Accepted: 06 February 2006
Mechanisms of eye development and evolution of the arthropod visual system: The lateral eyes of myriapoda are not modified insect ommatidiaDownload PDFAbstract
The lateral eyes of Crustacea and Insecta consist of many single optical units, the ommatidia, that are composed of a small, strictly determined and evolutionarily conserved set of cells. In contrast, the eyes of Myriapoda (millipedes and centipedes) are fields of optical units, the lateral ocelli, each of which is composed of up to several hundreds of cells. For many years these striking differences between the lateral eyes of Crustacea/Insecta versus Myriapoda have puzzled evolutionary biologists, as the Myriapoda are traditionally considered to be closely related to the Insecta. The prevailing hypothesis to explain this paradox has been that the myriapod fields of lateral ocelli derive from insect compound eyes by disintegration of the latter into single ommatidia and subsequent fusion of several ommatidia to form multicellular ocelli. To provide a fresh view on this problem, we counted and mapped the arrangement of ocelli during postembryonic development of a diplopod. Furthermore, the arrangement of proliferating cells in the eyes of another diplopod and two chilopods was monitored by labelling with the mitosis marker bromodeoxyuridine. Our results confirm that during eye growth in Myriapoda new elements are added to the side of the eye field, which extend the rows of earlier-generated optical units. This pattern closely resembles that in horseshoe crabs (Chelicerata) and Trilobita. We conclude that the trilobite, xiphosuran, diplopod and chilopod mechanism of eye growth represents the ancestral euarthropod mode of visual-system formation, which raises the possibility that the eyes of Diplopoda and Chilopoda may not be secondarily reconstructed insect eyes.
Received: 19 December 2005 / Accepted: 02 June 2006
Phylogenetic relationships of Serpulidae (Annelida: Polychaeta) based on 18S rDNA sequence data, and implications for opercular evolutionDownload PDFAbstract
Phylogenetic relationships of (19) serpulid taxa (including Spirorbinae) were reconstructed based on 18S rRNA gene sequence data. Maximum likelihood, Bayesian inference, and maximum parsimony methods were used in phylogenetic reconstruction. Regardless of the method used, monophyly of Serpulidae is confirmed and four monophyletic, well-supported major clades are recovered: the Spirorbinae and three groups hitherto referred to as the Protula-, Serpula-, and Pomatoceros-group. Contrary to the taxonomic literature and the hypothesis of opercular evolution, the Protula-clade contains non-operculate (Protula, Salmacina) and operculate taxa both with pinnulate and non-pinnulate peduncle (Filograna vs. Vermiliopsis), and most likely is the sister group to Spirorbinae. Operculate Serpulinae and poorly or non-operculate Filograninae are paraphyletic. It is likely that lack of opercula in some serpulid genera is not a plesiomorphic character state, but reflects a special adaptation.
Received: 30 June 2006 / Accepted: 06 July 2006
Species boundaries in Malagasy snakes of the genus Madagascarophis (Serpentes: Colubridae sensu lato) assessed by nuclear and mitochondrial markersDownload PDFAbstract
We studied mitochondrial divergence in 27 individuals of colubrid snakes of the genus Madagascarophis Mertens from most of its distribution area in Madagascar. Combined analyses of 16S rRNA and cytochrome b sequences identified six major clades which only partly agreed with previously proposed classifications. Analysis of nuclear DNA sequences of the c-mos gene as well as of ISSR fingerprints revealed consistent differences only among three clades which we consider as distinct species: a widespread Madagascarophis colubrinus (Schlegel), with M. citrinus (Boettger) as a junior synonym, a southern M. meridionalis Domergue, and a presumably undescribed species from the extreme north of Madagascar. The species M. ocellatus Domergue was not available for our study. Within M. colubrinus there are two populations from the north-west, each showing two divergent haplotypes with pairwise divergences of up to 5.2% in the cytochrome b gene. Maximum divergence in this gene within M. colubrinus was 7.1%. These high values emphasise that caution needs to be applied before genetic distance values are used for species delimitation. Phylogeographically, most of the genetic variation in M. colubrinus is found in northern Madagascar, indicating that the species might have originated in this region. Later one haplotype clade colonised western and eastern Madagascar, with a putative secondary introgression into north-western populations.
Received: 12 May 2006 / Accepted: 07 August 2006
Evolution in Carex L. sect. Spirostachyae (Cyperaceae): A molecular and cytogenetic approachDownload PDFAbstract
Carex sect. Spirostachyae comprises 25 species displaying the centre of diversity in Eurasia. Phylogenetic analysis of the ITS nrDNA region of 20 species of sect. Spirostachyae, six species of sect. Ceratocystis, five species of sect. Elatae, and eight outgroup species reveals that neither sect. Spirostachyae nor sect. Elatae is monophyletic. With the exclusion of Carex cretica, the 19 species of sect. Spirostachyae studied form a clade with the five species of tropical-subtropical sect. Elatae. Taxonomy of the core Spirostachyae is not only mostly in agreement with our phylogenetic hypothesis, but also with ecological and new cytogenetic results. Two main groups with different chromosome numbers and edaphic preferences are identified in the core Spirostachyae. One includes primarily acidophilous species with high chromosome numbers (2n=(64)68–84), whereas the other one includes mainly basophilous species with lower chromosome numbers (2n=60–74(75)). Chromosome-number variation is extremely different in the core Spirostachyae, showing great stability in some widespread species (e.g. Carex extensa) but an active chromosome evolution – faster chromosomal rearrangements, fusion and fission events than ITS nucleotide substitutions – in more restricted species (e.g. Carex troodi). Biogeography of the two amphiatlantic pairs of species reveals two independent colonizations of South America from the European continent. The geographical barrier of the Strait of Gibraltar has played different roles in the course of evolution of this section, acting as an effective barrier to gene flow in one case (Carex helodes) but as a limited barrier or recent separation in two others (Carex distans, Carex punctata).
Received: 18 October 2005 / Accepted: 10 March 2006
Evolution of taxodiaceous Cupressaceae (Coniferopsida)Download PDFAbstract
The evolution of taxodiaceous Cupressaceae has been discussed controversially, because phylogenetic analyses using non-molecular data show major differences to molecular analyses. To solve this problem, we used non-molecular data with a high probability of homology. With these type of data, we could show for the first time in taxodiaceous Cupressaceae that phylogenetic trees of molecular and non-molecular data share the same topology. Investigation of female cone development also contributes to better understanding of morphology and anatomy in taxodiaceous Cupressaceae. Additional developmental, fossil and cone configuration data support the topology constructed by using the molecular and non-molecular data.
Received: 25 January 2006 / Accepted: 06 July 2006
Phylogenetic analysis of Remipedia (Crustacea)Download PDFAbstract
We present a cladistic analysis of the crustacean class Remipedia, including all 17 extant species currently assigned to the order Nectiopoda, with the Carboniferous fossil Tesnusocaris serving as an outgroup. We applied different methodological approaches and coding options to a basic matrix composed of 26 morphological characters. Our analyses strongly support monophyly of the Godzilliidae and affirm justification of the family Micropacteridae. However, the present taxonomic structure within the Speleonectidae is partly incompatible with our results, and we cannot exclude that the family is paraphyletic.
Received: 03 November 2005 / Accepted: 02 June 2006
Redescription of Petrolisthes edwardsii (de Saussure) and description of a new, sibling species from the eastern Pacific based on different colour, morphology and genetic identity (Crustacea: Anomura: Porcellanidae)Download PDFAbstract
Petrolisthes edwardsii (de Saussure, 1853) has been viewed as a morphologically variable species with a wide distribution in the tropical and subtropical eastern Pacific. The original description of this species is rather inaccurate, and for more than a century there has been confusion regarding the final repository of type specimens. Material recently collected in the tropical eastern Pacific revealed two different colour morphs, also distinguishable through subtle discrete and continuous differences. Detailed examination of the adult morphology of these two morphotypes and phylogenetic analysis of DNA sequences of a fragment of the mitochondrial COI gene were consistent in the separation of the two forms, irrespective of the geographic origin of the specimens. Therefore, we treat these forms as different species. One form is newly described as Petrolisthes donadio n. sp., the other redescribed as P. edwardsii. The two species live in sympatry across most of their geographic range, and occupy similar habitats. A possible geographical mode of speciation is discussed.
Received: 31 October 2005 / Accepted: 25 January 2006
Speciation of two sympatric coastal fish species, Girella punctata and Girella leonina (Perciformes, Kyphosidae)Download PDFAbstract
Girella punctata and Girella leonina are sympatric sister species showing extensive distributional overlap in shallow rocky reefs in the Pacific Ocean south of the Japanese Islands. Differences between the two species in external morphological characters, such as number of pored lateral line scales, colour of opercular flap and shape of caudal fin, are congruent with genetic divergence. Nucleotide identity between the two species in the 3.3kbp region of partial mitochondrial DNA containing the D-loop region, in 12S and 16S ribosomal RNA (rRNA) and transfer RNA genes is 95%. To estimate divergence time, Bayesian analysis was conducted using a dataset comprising concatenated nucleotide sequences from the two rRNA genes of three girellid and nine other fish species. Using the Elopomorpha – Clupeocephala split (265 million years ago (mya)) as a calibration point, divergence between G. punctata and G. leonina is estimated as having occurred 6.0±1.4mya. Speciation is suggested to have been caused by geographical isolation associated with formation of the Japanese Islands, which resulted in disjunction of Girella habitat.
Received: 14 October 2005 / Accepted: 17 May 2006
A genus-level supertree of Adephaga (Coleoptera)Download PDFAbstract
A supertree for Adephaga was reconstructed based on 43 independent source trees – including cladograms based on Hennigian and numerical cladistic analyses of morphological and molecular data – and on a backbone taxonomy. To overcome problems associated with both the size of the group and the comparative paucity of available information, our analysis was made at the genus level (requiring synonymizing taxa at different levels across the trees) and used Safe Taxonomic Reduction to remove especially poorly known species. The final supertree contained 401 genera, making it the most comprehensive phylogenetic estimate yet published for the group. Interrelationships among the families are well resolved. Gyrinidae constitute the basal sister group, Haliplidae appear as the sister taxon of Geadephaga+Dytiscoidea, Noteridae are the sister group of the remaining Dytiscoidea, Amphizoidae and Aspidytidae are sister groups, and Hygrobiidae forms a clade with Dytiscidae. Resolution within the species-rich Dytiscidae is generally high, but some relations remain unclear. Trachypachidae are the sister group of Carabidae (including Rhysodidae), in contrast to a proposed sister-group relationship between Trachypachidae and Dytiscoidea. Carabidae are only monophyletic with the inclusion of a non-monophyletic Rhysodidae, but resolution within this megadiverse group is generally low. Non-monophyly of Rhysodidae is extremely unlikely from a morphological point of view, and this group remains the greatest enigma in adephagan systematics. Despite the insights gained, our findings highlight that a combined and coordinated effort of morphologists and molecular systematists is still required to expand the phylogenetic database to enable a solid and comprehensive reconstruction of adephagan phylogeny. See also Supplementary material in the online edition at doi:10.1016/j.ode.2006.05.003