Miocene diversification of an open‐habitat predatorial passerine radiation,the shrikes (Aves: Passeriformes: Laniidae)

Diversification of avifaunas associated with savannah and steppes appears to correlate with open habitats becoming available, starting in the Miocene. Few comparative analyses exist for families for which all species are predominantly adapted to these habitats. One such group is Laniidae (Passeriformes), which are small‐ to medium‐sized predatory passerines known for their distinctive behaviour of impaling prey. We used multispecies coalescent‐based and concatenation methods to provide the first complete species‐level phylogeny for this group, as well as an estimate of the timing of diversification. Our analyses indicate that Laniidae as currently delimited is not monophyletic, as the genus Eurocephalus is not closely related to the remaining species. The two species currently assigned to the monotypic genera Urolestes and Corvinella are part of the same clade as the Lanius species, and we propose that they are included in the genus Lanius, making Laniidae monogeneric. The initial diversification of the clade is inferred to have occurred very rapidly, starting about 7.2–9.1 million years ago, timing depending on calibration method, but in either case coinciding with the expansion of C4 grasses. An African origin is inferred in the biogeographic analysis. In the redefined Laniidae, cooperative breeding is inferred to be restricted to a single clade, characterized by gregarious behaviour and rallying. Migratory behaviour evolved multiple times within the family.     

Molecular systematics and Holarctic phylogeography of cestodes of the genus Anoplocephaloides Baer, 1923 s. s. (Cyclophyllidea,Anoplocephalidae) in lemmings (Lemmus,Synaptomys)

The present molecular systematic and phylogeographic analysis is based on sequences of cytochrome c oxidase subunit 1 (cox1) (mtDNA) and 28S ribosomal DNA and includes 59 isolates of cestodes of the genus Anoplocephaloides Baer, 1923 s. s. (Cyclophyllidea, Anoplocephalidae) from arvicoline rodents (lemmings and voles) in the Holarctic region. The emphasis is on Anoplocephaloides lemmi (Rausch 1952) parasitizing Lemmus trimucronatus and Lemmus sibiricus in the northern parts of North America and Arctic coast of Siberia, and Anoplocephaloides kontrimavichusi (Rausch 1976) parasitizing Synaptomys borealis in Alaska and British Columbia. The cox1 data, 28S data and their concatenated data all suggest that A. lemmi and A. kontrimavichusi are both non‐monophyletic, each consisting of two separate, well‐defined clades, that is independent species. As an example, the sister group of the clade 1 of A. lemmi, evidently representing the ‘type clade’ of this species, is the clade 1 of A. kontrimavichusi. For A. kontrimavichusi, it is not known which one is the type clade. There is also fairly strong evidence for the non‐monophyly of Anoplocephaloides dentata (Galli‐Valerio, 1905)‐like species, although an earlier phylogeny suggested that this multispecies assemblage may be monophyletic. The results suggest a deep phylogenetic codivergence of Lemmus spp. and A. lemmi, primarily separating the two largely allopatric host and parasite species at the Kolyma River in east Siberia. There are also two allopatric sublineages within each main clade/species of A. lemmi and Lemmus, but the present distributions of the sublineages within the eastern L. trimucronatus and clade 1 of A. lemmi are not concordant. This discrepancy may be most parsimoniously explained by an extensive westward distributional shift of the easternmost parasite subclade. The results further suggest that the clade 1 of A. kontrimavichusi has diverged through a host shift from the precursor of L. trimucronatus to S. borealis.     

Molecular phylogeny of Enchytraeidae (Oligochaeta) indicates separate invasions of the terrestrial environment

Enchytraeidae is a family of soil inhabiting small‐ to medium‐sized oligochaete worms using degradable plant material as a food source and primarily adapted to terrestrial or semi‐terrestrial environments. The molecular phylogeny based upon both mitochondrial and nuclear genes indicates early segregations of the two genera Enchytraeus and Lumbricillus leaving the remaining genera included in this study as a later segregated major monophyletic branch. Extant members of the two former genera dominate in decaying seaweed in the littoral zone along the sea although members of in particular the genus Enchytraeus have also invaded other habitats. Historically the littoral zone of the sea is undoubtedly the first terrestrial or semi‐terrestrial habitat where dead plant material accumulates to any greater extent and Enchytraeus and Lumbricillus may represent early successful attempts to exploit this resource. Inland soils probably had to await the emergence of land plants in order to provide a similar food resource and here the major branch of enchytraeid genera diversified into a high number of species in the numerous decomposer networks of this varied environment. A subdivision into the genera Enchytraeus and Lumbricillus on the one hand and a branch of mainly inland genera on the other is supported by differences in two somewhat neglected morphological features. Firstly, in Enchytraeus and Lumbricillus the testes are enclosed in a testis sac within which the male cells mature, by one possible exception a unique feature among Oligochaeta, The other enchytraeid genera studied and Oligochaeta in general lack this sac and the male cells mature directly in the cavity of the testicular segment. Secondly, species of Enchytraeus and Lumbricillus generally have a higher reproductive output than species of the inland terrestrial branch and this may represent an adaptation to the unpredictable littoral zone compared to the more stable nature of inland habitats. In the older literature the genus Mesenchytraeus is considered to have a basic position within the entire family but our molecular data do not support this expectation. In Enchytraeidae the nephridia are elaborate organs of a characteristic and constant shape covering species from different genera in a pattern following the molecular phylogeny. Other much used morphological features such as shape of setae, anteclitellar origin of the dorsal vessel and various modifications of the intestine have arisen more than once.     

Geographical structure,narrow species ranges,and Cenozoic diversification in a pantropical clade of epiphyllous leafy liverworts

The evolutionary history and classification of epiphyllous cryptogams are still poorly known. Leptolejeunea is a largely epiphyllous pantropical liverwort genus with about 25 species characterized by deeply bilobed underleaves, elliptic to narrowly obovate leaf lobes, the presence of ocelli, and vegetative reproduction by cladia. Sequences of three chloroplast regions (rbcL, trnL‐F, psbA) and the nuclear ribosomal ITS region were obtained for 66 accessions of Leptolejeunea and six outgroup species to explore the phylogeny, divergence times, and ancestral areas of this genus. The phylogeny was estimated using maximum‐likelihood and Bayesian inference approaches, and divergence times were estimated with a Bayesian relaxed clock method. Leptolejeunea likely originated in Asia or the Neotropics within a time interval from the Early Eocene to the Late Cretaceous (67.9 Ma, 95% highest posterior density [HPD]: 47.9–93.7). Diversification of the crown group initiated in the Eocene or early Oligocene (38.4 Ma, 95% HPD: 27.2–52.6). Most species clades were established in the Miocene. Leptolejeunea epiphylla and L. schiffneri originated in Asia and colonized African islands during the Plio‐Pleistocene. Accessions of supposedly pantropical species are placed in different main clades. Several monophyletic morphospecies exhibit considerable sequence variation related to a geographical pattern. The clear geographic structure of the Leptolejeunea crown group points to evolutionary processes including rare long‐distance dispersal and subsequent speciation. Leptolejeunea may have benefitted from the large‐scale distribution of humid tropical angiosperm forests in the Eocene.     

Molecular phylogeny of Potamotrygonocotyle (Monogenea,Monocotylidae) challenges the validity of some of its species

Fehlauer‐Ale, K. H. & Littlewood, D. T. J. (2011). Molecular phylogeny of Potamotrygonocotyle (Monogenea, Monocotylidae) challenges the validity of some of its species. —Zoologica Scripta, 40, 638–658. The marine‐derived stingrays Potamotrygonidae are the only chondrichthyans landlocked to freshwaters of Central and South America. The family includes approximately 22 described species organized in four genera widely distributed across the main Atlantic and Caribbean continental drainages. Investigations into the parasite fauna of potamotrygonids have mainly focused on cestodes, with a few studies addressing the biodiversity of monogeneans. Potamotrygonocotyle (Monogenea, Monocotylidae) is composed of 12 species, exclusively found in the gills of species of Potamotrygonidae. This study presents molecular phylogenetic analyses of this group of monogeneans distributed throughout La Plata and Amazonas basins, with the purpose of readdressing the phylogeny of Monocotylidae based on 28S rDNA sequences and of unravelling the phylogeny of its species using data from mitochondrial gene cytochrome c oxidase subunit I and nuclear gene internal transcribed spacer 1. The phylogenetic status of the five tested monocotylid subfamilies and most of their internal relationships are concordant with the results of a previous study, and the monophyletic status of Potamotrygonocotyle based on molecular data is corroborated for the first time. However, the placement of the genus within Monocotylidae is not resolved, as its sister‐group relationship with Neoheterocotyle and Troglocephalus is uncertain. Investigations into the relationships within Potamotrygonocotyle support the monophyletic status of nine nominal species and suggest the existence of cryptic lineages for the remaining three. Molecular analyses reveal distinct sister‐groups relationships in comparison with a previously published phylogeny for the genus based on morphological data. Finally, the surveys of this study expand the known distribution range of some members of Potamotrygonocotyle.     

Molecular systematics of threadfin breams and relatives (Teleostei,Nemipteridae)

Threadfin breams and relatives of the family Nemipteridae comprise 69 currently recognized species in five genera. They are found in the tropical and subtropical Indo‐West Pacific and most are commercially important. Using recently developed molecule‐based approaches exploiting DNA sequence variation among species/specimens, this study reconstructed a comprehensive phylogeny of the Nemipteridae, examined the validity of species and explored the cryptic diversity of the family, and tested previous phylogenetic hypotheses. A combined data set (105 taxa from 41 morphospecies) with newly determined sequences from two nuclear genes (RAG1 and RH) and one mitochondrial gene (COI), and a data set with only COI gene sequences (329 newly obtained plus 328 from public databases from a total of 53 morphospecies) were used in the phylogenetic analysis. The latter was further used for species delimitation analyses with two different tools to explore species diversity. Our phylogenetic results showed that all the currently recognized genera were monophyletic. The monotypic genus Scaevius is the sister group of Pentapodus and they together are sister to Nemipterus. These three genera combined to form the sister group of the clade comprising Parascolopsis and Scolopsis. The validity of most of the examined species was confirmed except in some cases. The combined evidence from the results of different analyses revealed a gap in our existing knowledge of species diversity in the Nemipteridae. We found several currently recognized species contain multiple separately evolving metapopulation lineages within species; some lineages should be considered as new species for further assignment. Finally, some problematic sequences deposited in public databases (probably due to misidentification) were also revised in this study to improve the accuracy for prospective DNA barcoding work on nemipterid fishes.     

Molecular systematics of the neotropical shovelnose catfish genus Pseudoplatystoma Bleeker 1862 based on nuclear and mtDNA markers

Pseudoplatystoma is a commercially important genus of Neotropical migratory catfishes widely distributed in all major river basins of South America. Historically, only three species were recognized, but a recent revision proposed eight putative morphospecies for the genus. A molecular study based on mitochondria DNA (mtDNA) provided support for recognition of only some of the species and raised questions about species boundaries in this group. We present a more encompassing analysis based on mtDNA (cytochrome b, 818bp) and nuclear DNA-based phylogenies (Rag1 intron 1, 664bp and S7 intron 1, 635bp) for a more extensive sampling (279 individuals from 42 localities) of all putative species in all major river basins. Patterns generated by individual gene genealogies and a multispecies coalescent analysis provided evidence to suggest recognition of only four distinct species in this genus: Pseudoplatystoma magdaleniatum, Pseudoplatystoma corruscans, Pseudoplatystoma tigrimun (sensu lato) and Pseudoplatystoma fasciatum (sensu lato). The species phylogeny places P. magdaleniatum as the sister group to all the other species in the genus, but the relationships among P. fasciatum s.l, P. tigrimum s.l., and P. corruscans could not be resolved with confidence.     

A molecular phylogenetic analysis of Bulinus (Gastropoda: Planorbidae) with conserved nuclear genes

Jørgensen, A., Madsen, H., Nalugwa, A., Nyakaana, S., Rollinson, D., Stothard, J. R. & Kristensen, T. K. A molecular phylogenetic analysis of Bulinus (Gastropoda: Planorbidae) with conserved nuclear genes. —Zoologica Scripta, 40, 126–136. Mutational saturation of inspected DNA loci and topological incongruence in the phylogenetic inferences have previously confounded attempts to resolve the evolutionary relationships within the freshwater snail genus Bulinus. Traditionally, the 37 species of Bulinus are placed within the four species groups and the evolutionary divergence between groups is substantial. With an intention to shed new light on species group relationships, the present study was designed to investigate the basal divergences in the phylogeny of Bulinus using highly conserved nuclear genes. The resolved phylogeny inferred that the four species groups of Bulinus were monophyletic and Shimodaira‐Hasegawa topology tests found them to be significantly supported. The Bulinus truncatus/tropicus species complex and Bulinus wrighti (Bulinus reticulatus group) formed a well‐supported sister‐group relationship. The Bulinus africanus species group was the sister‐group to the clade (Bulinus truncatus/tropicus + B. wrighti) with the Bulinus forskalii species group as the sister‐group to these taxa. The sister‐group relationship between Indoplanorbis and Bulinus was non‐significant and the basal clade support of Bulinus improved upon exclusion of Indoplanorbis. The finding of basal long branches of Bulinus species originating from Madagascar strongly suggests the presence of additional cryptic species and an evolutionary scenario influenced by this island’s geological vicariance from the African mainland. Speciation by polyploidy was inferred to have evolved within a clade in the Bulinus truncatus/tropicus species complex. Although the monophyletic status of each species group was firmly supported, it was difficult to establish species group concepts equally across the variations and place this precisely in a specific temporal framework.     

Phylogenetic evidence for loss of sound production and a shift in sexual recognition signals in Hamadryas butterflies (Nymphalidae: Biblidinae)

The neotropical butterfly genus Hamadryas Hübner comprises 20 species that exhibit an intriguing variation in their natural history traits. Although revised in 1983, no phylogenetic hypothesis was presented: the first phylogenetic hypothesis is estimated here based on 93 characters and including species from the three other genera in the tribe Ageroniini. The phylogeny is used to test the monophyly of the genus, establish the sister group of Hamadryas and identify its apomorphies. The tree allows the inference of patterns of character change in sound production and sexual dimorphism. Implied weights show that Hamadryas is monophyletic and corroborate Ectima Doubleday as a sister genus. Previously suggested subgenera for Hamadryas were non‐monophyletic, with the exception of the laodamia clade, supported by the presence of a complete sterigma. Sound production is inferred to be a derived condition in Hamadryas that has been lost in the laodamia clade. This, plus the presence of androconial organs and sexual dimorphism in the laodamia clade, suggests a shift in sexual recognition signalling. Furthermore, the phylogeny indicates that the colour pattern of males in the laodamia clade is novel, supporting a Darwinian origin of sexual dimorphism.     

The hidden history of the snowshoe hare,Lepus americanus: extensive mitochondrial DNA introgression inferred from multilocus genetic variation

Hybridization drives the evolutionary trajectory of many species or local populations, and assessing the geographic extent and genetic impact of interspecific gene flow may provide invaluable clues to understand population divergence or the adaptive relevance of admixture. In North America, hares (Lepus spp.) are key species for ecosystem dynamics and their evolutionary history may have been affected by hybridization. Here we reconstructed the speciation history of the three most widespread hares in North America – the snowshoe hare (Lepus americanus), the white‐tailed jackrabbit (L. townsendii) and the black‐tailed jackrabbit (L. californicus) – by analysing sequence variation at eight nuclear markers and one mitochondrial DNA (mtDNA) locus (6240 bp; 94 specimens). A multilocus–multispecies coalescent‐based phylogeny suggests that L. americanus diverged ~2.7 Ma and that L. californicus and L. townsendii split more recently (~1.2 Ma). Within L. americanus, a deep history of cryptic divergence (~2.0 Ma) was inferred, which coincides with major speciation events in other North American species. While the isolation‐with‐migration model suggested that nuclear gene flow was generally rare or absent among species or major genetic groups, coalescent simulations of mtDNA divergence revealed historical mtDNA introgression from L. californicus into the Pacific Northwest populations of L. americanus. This finding marks a history of past reticulation between these species, which may have affected other parts of the genome and influence the adaptive potential of hares during climate change.     

Evolution of the Neotropical ant genus Linepithema

Abstract A comprehensive species‐level phylogeny of the ant genus Linepithema Mayr, a Neotropical group best known for the invasive Argentine ant L. humile (Mayr), is inferred for the first time using fragments from three nuclear loci [wingless (WG), long‐wavelength rhodopsin (LWR) and internal transcribed spacer (ITS‐2)] and the mitochondrial cytochrome oxidase subunit I (COI) gene. Monophyly of the genus is strongly supported in parsimony, likelihood and Bayesian analyses of the concatenated data, as is the monophyly of four species groups defined previously on the basis of morphology. An Andean species, L. oblongum (Santschi), is the sister taxon of the Argentine ant. Eight of the 11 species whose monophyly was testable in the analysis were inferred to be monophyletic. Several instances of species paraphyly and one case of mitochondrial introgression suggest that complex population genetic processes underpin the patterns of diversity in Linepithema, and that simple genetic approaches to taxonomy such as DNA barcoding should be treated with caution. A maximum likelihood reconstruction of ancestral distributions suggests that Linepithema is of southern South American origin and that populations in the Greater Antilles are the result of four independent colonization events.     

Multilocus phylogeny and species delimitation within the genus Glauconycteris (Chiroptera,Vespertilionidae), with the description of a new bat species from the Tshopo Province of the Democratic Republic of the Congo

The genus Glauconycteris Dobson, 1875 currently contains 12 species of butterfly bats, all endemic to sub‐Saharan Africa. Most species are rarely recorded, with half of the species known from less than six geographic localities. The taxonomic status of several species remains problematic. Here, we studied the systematics of butterfly bats using both morphological and molecular approaches. We examined 45 adult specimens for external anatomy and skull morphology, and investigated the phylogeny of Glauconycteris using DNA sequences from three mitochondrial genes and 116 individuals, which in addition to outgroup taxa, included nine of the twelve butterfly bat species currently recognized. Four additional nuclear genes were sequenced on a reduced sample of 69 individuals, covering the outgroup and Glauconycteris species. Our molecular results show that the genus Glauconycteris is monophyletic, and that it is the sister‐group of the Asian genus Hesperoptenus. Molecular dating estimates based on either Cytb or RAG2 data sets suggest that the ancestor of Glauconycteris migrated into Africa from Asia during the Tortonian age of the Late Miocene (11.6–7.2 Mya), while the basal diversification of the crown group occurred in Africa at around 6 ± 2 Mya. The species G. superba is found to be the sister‐group of G. variegata, questioning its placement in the recently described genus Niumbaha. The small species living in tropical rainforests constitute a robust clade, which contains three divergent lineages: (i) the “poensis” group, which is composed of G. poensis, G. alboguttata, G. argentata, and G. egeria; (ii) the “beatrix” group, which contains G. beatrix and G. curryae; and (iii) the “humeralis” group, which includes G. humeralis and a new species described herein. In the “poensis” group, G. egeria is found to be monophyletic in the nuclear tree, but polyphyletic in the mitochondrial tree. The reasons for this mito‐nuclear discordance are discussed.     

Evolutionary history of mole rats (genus Nannospalax) inferred from mitochondrial cytochrome b sequence

Mole rats (genus Nannospalax) display prolific chromosomal variation with more than 50 distinct cytotypes. These cytotypes are largely indistinguishable morphologically, are mainly allopatric and their taxonomic ranking is contradictory. We established a cytochrome b phylogeny for 15 cytotypes belonging to all three species recognized on morphological grounds (morphospecies): N. leucodon, N. xanthodon and N. ehrenbergi. Phylogenetic reconstructions yielded two highly divergent groups which are in agreement with the current division into two subgenera (Nannospalax and Mesospalax). The former comprised samples from south‐eastern Turkey, Israel and Egypt (the morphospecies N. ehrenbergi). Basal dichotomy within Mesospalax remained unresolved and the putative sister position of N. leucodon against the two lineages of N. xanthodon was not supported in our analysis. Net divergences between sister cytotypes were low (< 2.0%) and two N. leucodon cytotypes were not even reciprocally monophyletic. Among the three morphospecies, the genetic diversity was lowest in N. leucodon (2.4% ± 0.3%), highest in N. xanthodon (8.8% ± 0.7%) and intermediate in N. ehrenbergi (5.0% ± 0.5%). Our results show that associations between genetic and chromosomal variation are not widespread and common in mole rats, and therefore refute the generalization of a ‘cytotype‐equals‐species’ approach. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105 , 446–455.     

Phylogeny of Mesoamerican freshwater mussels and a revised tribe‐level classification of the Ambleminae

Evolutionary and ecological hypotheses of the freshwater mussel subfamily Ambleminae are intensely geographically biased—a consequence of the complete exclusion of Mesoamerican taxa in phylogenetic reconstructions of the clade. We set out to integrate a portion of the Mesoamerican freshwater mussel assemblage into existing hypotheses of amblemine classification and evolution by generating a molecular phylogeny that includes four previously unsampled Mesoamerican genera and nine species endemic to that region. Given the traditionally hypothesized affinity to Nearctic mussels and the understanding that classification should reflect common ancestry, we predicted that (a) Mesoamerican genera would be recovered as members of the recognized tribes of the Ambleminae, and (b) genera would be supported as monophyletic. The mutilocus phylogeny (COI + 28S + 16S) reported herein does not fully support either of those hypotheses. Neither Cyrtonaias nor Psorula were supported as monophyletic and we predict several other Mesoamerica genera are also non‐monophyletic. The reconstructed phylogeny recovered four independent lineages of Mesoamerican freshwater mussels and these clades are distributed across the phylogeny of the Ambleminae, including the tribe Quadrulini (Megalonaias), Lampsilini (two lineages: Cyrtonaias explicata/Sphenonaias microdon, and Pachynaias), and a previously unrecognized, exclusively Mesoamerican and Rio Grande clade consisting of the genera Psoronaias, Psorula and Popenaias. The latter clade possesses several morphological characteristics that distinguish it from its sister taxon, tribe Lampsilini, and we recognize this newly identified Mesoamerican clade as a fifth tribe of the Ambleminae attributable to the Popenaiadini Heard & Guckert, 1970. This revised classification more completely recognizes the suprageneric diversity of the Ambleminae.     

Phylogenetic relationships of the New World Troidini swallowtails (Lepidoptera: Papilionidae) based on COI, COII, and EF-1α genes

A phylogeny of the Neotropical members of the Tribe Troidini (Lepidoptera: Papilionidae) was obtained with sequences of three protein-coding genes: two mitochondrial (COI and COII), and one nuclear (EF-1α). Parsimony and Bayesian analyses of 33 taxa resulted in very similar trees regardless of method used with the 27 troidines always forming a monophyletic clade. Within Troidini, the genus Battus is sister group to the remaining troidines, followed by a clade formed by the Paleotropical taxa (here represented by three exemplars). The genus Euryades is the next branch, and sister group of Parides. The genus Parides is monophyletic, and is divided into four main groups by Maximum Parsimony analysis, with the most basal group composed of tailed species restricted to SE Brazil. Character optimization of ecological and morphological traits over the phylogeny proposed for troidines indicated that the use of several species of Aristolochia is ancestral over the use of few or a single host-plant. For the other three characters, the ancestral states were the absence of long tails, forest as the primary habitat and oviposition solitary or in loose group of several eggs.     

The endemic Cladophorales (Ulvophyceae) of ancient Lake Baikal represent a monophyletic group of very closely related but morphologically diverse species

Lake Baikal, the oldest lake in the world, is home to spectacular biodiversity and extraordinary levels of endemism. While many of the animal species flocks from Lake Baikal are famous examples of evolutionary radiations, the lake also includes a wide diversity of endemic algae that are not well investigated with regards to molecular‐biological taxonomy and phylogeny. The endemic taxa of the green algal order Cladophorales show a range of divergent morphologies that led to their classification in four genera in two families. We sequenced partial large‐ and small‐subunit rDNA as well as the internal transcribed spacer region of 14 of the 16 described endemic taxa to clarify their phylogenetic relationships. One endemic morphospecies, Cladophora kusnetzowii, was shown to be conspecific with the widespread Aegagropila linnaei. All other endemic morphospecies formed a monophyletic group nested within the genus Rhizoclonium (Cladophoraceae), a very surprising result, in stark contrast to their morphological affinities. The Baikal clade represents a species flock of closely related taxa with very low genetic differentiation. Some of the morphospecies were congruent with lineages recovered in the phylogenies, but due to the low phylogenetic signal in the rDNA sequences the relationships within the Baikal clade were not all well resolved. The Baikal clade appears to represent a recent radiation, based on the low molecular divergence within the group, and it is hypothesized that the large morphological variation results from diversification in sympatry from a common ancestor in Lake Baikal.     

Phylogenetic relationships within Luzula DC. and Juncus L. (Juncaceae): A comparison of phylogenetic signals of trnL-trnF intergenic spacer, trnL intron and rbcL plastome sequence data

Juncus and Luzula are the largest, almost cosmopolitan, genera in the Juncaceae. Relationships within Juncus and Luzula and among other genera of Juncaceae (Distichia, Marsippospermum, Oxychloë, Patosia and Rostkovia) remain incompletely resolved. RbcL sequence data resolved a part of the supraspecific phylogeny, but many clades remain polytomic. For this reason, the non‐coding cpDNA regions, trnL intron and trnL‐trnF intergenic spacer, were sequenced. We intended to create hypotheses of relationships within Juncaceae and to test the classification of the sections, but a primary goal to this study was to assess the relationships within Juncus and Luzula and to test for monophyly of groups recognized from rbcL data (especially the monophyly of genus Luzula and the Southern Hemisphere Clade (SHC)). Furthermore, we tested the influence of different rooting and ingroup composition on the tree topology. The parsimony analyses revealed several well‐supported lineages. The traditionally distinguished genus Luzula is monophyletic and Juncus is non‐monophyletic. Two subgenera of Luzula (Pterodes and Luzula) are non‐monophyletic, while subg. Marlenia forms a sister group to the whole Luzula clade (trnL‐F data set). Within Juncus, both subgenus Juncus and subgenus Agathryon are non‐monophyletic. SHC is clustered not only with the South African J. lomatophylus and J. capensis, but also together with members of the section Juncus, Caespitosi and Graminifolii. These sections form a well‐separated sister group to the SHC. Within the genera Juncus and Luzula, monophyly is demonstrated for a number of groups (e.g., Juncus section Stygiopsis, Luzula section Luzula) but questioned for others (e.g., Juncus section Graminifolii). The unusual, separate positioning of Juncus trifidus and J. monanthos were clarified by trnL‐trnF sequence data, but vary within the tree topology depending on outgroup selection and also due to LBA phenomenon. © The Willi Hennig Society 2006.     

Conserved shell disguises diversity in Mesodontrachia land snails from the Australian Monsoon Tropics (Gastropoda: Camaenidae)

We comprehensively revise the taxonomy of the camaenid genus Mesodontrachia Solem, 1985, which is endemic to the Victoria River District and East Kimberley in the north‐western Australian Monsoon Tropics based on comparative analyses of key morphological features and mitochondrial DNA sequences. We examined newly collected samples from several collection sites spread over nearly 20 000 km² of mostly inaccessible land, which represented all three currently known and three previously undescribed species. All species were initially identified as members of Mesodontrachia based on their similar, putatively typical shell. However, Mesodontrachia as so delimited was polyphyletic in a mitochondrial phylogeny with respect to several other camaenid genera from NW Australia. Contrary to the shell, we found considerable variation in the penial anatomy that was consistent with the mtDNA differentiation. To retain monophyletic taxa, we propose a revised taxonomy whereby Mesodontrachia is maintained as a monotypic taxon. In addition, four genera (Nodulabium, Ototrachia, Pseudomesodontrachia and Vincentrachia) and three species (P. gregoriana, O. compressa and N. solidum) are newly described. The shell of all these taxa is highly conserved and of little taxonomic utility. Shell similarity is attributed to a similar life style in a similar and harsh environment.