Molecular phylogeny of North American Branchiobdellida (Annelida: Clitellata)

Branchiobdellidans, or crayfish worms, are ectosymbiotic clitellate annelids associated primarily with freshwater crayfishes. The main objectives of our study were to infer a molecular phylogeny for the North American Branchiobdellida, examine its congruence with morphology-based hypotheses of relationships at the subfamily and genus level, and use our dataset to assess consistency of GenBank-archived branchiobdellidan sequences. We used nucleotide sequence data from two mtDNA genes (COI and 16S rDNA) and three nuclear genes (28S rDNA, 18S rDNA, and ITS1) to estimate phylogenetic relationships among 47 described and one undescribed species of Branchiobdellida. We recovered a monophyletic branchiobdellidan clade with generally short branch lengths, suggesting that a large portion of the taxon has likely undergone a recent and rapid radiation in North America. Results from our phylogenetic analyses indicate that current taxonomic groupings are largely unsupported by the molecular data. All four subfamilies are either paraphyletic or polyphyletic, and only three of seven sampled non-monotypic genera were monophyletic. We found a high rate (49%) of inconsistency in GenBank-archived sequences, over 70% of which can be attributed to field- or laboratory-based error.     

Molecular phylogeny of lugworms (Annelida, Arenicolidae) inferred from three genes

Arenicolids comprise a group of four genera in which about 30 nominal species are described. Whereas the biology of many arenicolids is well known, the phylogenetic relationships of these worms are inadequately studied. A close relationship of Arenicolidae and Maldanidae is generally accepted. The phylogenetic relationships of arenicolid taxa were reconstructed based on sequence data of the mitochondrial 16S rRNA gene, the nuclear 18S rRNA gene, and a small fraction of the nuclear 28S rRNA gene. Members of all described arenicolid genera are included in the data set. Phylogenetic analyses were conducted using Maximum Likelihood, Bayesian inference, and Maximum Parsimony. The monophyly of the Maldanidae, as well as of the Arenicolidae is supported by all conducted analyses. Two well supported major clades are highest ranked sister taxa in the Arenicolidae: one containing all Abarenicola species and one containing Arenicola, Arenicolides, and Branchiomaldane. Evidence is given for a closer relationship between the two investigated Branchiomaldane species and Arenicolides ecaudata in the combined analysis. In the light of the molecular data the best explanation for structural and morphological observations is that Branchiomaldane evolved by progenesis.     

18S rDNA phylogeny of Clitellata (Annelida)

The phylogeny of Clitellata was analysed using 18S rDNA sequences of a selection of species representing Hirudinida, Acanthobdellida, Branchiobdellida and 10 oligochaetous families. Eleven new 18S sequences of Capilloventridae (one), Haplotaxidae (one), Propappidae (one), Enchytraeidae (two), Lumbricidae (one), Almidae (one), Megascolecidae (two), Lumbriculidae (one), and Phreodrilidae (one) are reported and aligned together with corresponding sequences of 28 previously studied clitellate taxa. Twelve polychaete species were used as an outgroup. The analysis supports an earlier hypothesis based on morphological features that Capilloventridae represents a basal clade of Clitellata; in the 18S tree it shows a sister-group relationship to all other clitellates. The remaining clitellate taxa form a basal dichotomy, one clade containing Tubificidae (including the former 'Naididae'), Phreodrilidae, Haplotaxidae, and Propappidae, the other clade with two subgroups: (1) Lumbriculidae together with all leech-like taxa (Acanthobdellida, Branchiobdellida and Hirudinida), and (2) Enchytraeidae together with a monophyletic group of all earthworms included in the study (Lumbricidae, Almidae and Megascolecidae). These earthworms are members of the taxon Crassiclitellata, the monophyly of which is thus supported by the data. The tree also shows support for the hypothesis that the first clitellates were aquatic. The position of the single species representing Haplotaxidae is not as basal as could have been expected from earlier morphology-based conclusions about the ancestral status of this family. However, if Haplotaxidae is indeed a paraphyletic assemblage of relict taxa, a higher number of representatives will be needed to resolve its exact relationships with the other clitellates.     

Molecular phylogeny of naidid worms (Annelida: Clitellata) based on cytochrome oxidase I

Naidids are tiny, primarily freshwater oligochaete annelids which reproduce asexually by fission. We investigated the phylogenetic relationships within this group by sequencing 1224 bp of the mitochondrial gene cytochrome oxidase I (COI) from 26 species of naidids (representing 13 of the 23 genera currently recognized), as well as from four tubificids, their closest allies. Although not completely concordant, maximum parsimony and Bayesian inference analyses agreed in several important respects, with no well-supported conflicts. Our study, the first detailed molecular investigation of naidid relationships, suggests that naidids fall into two groups, one comprised of the genus Pristina, and another comprised of all other genera sampled. The clear division of naidids into these two groups best matches an early, simple classification of the group by Lastockin (1924); the more recent classifications proposed by Sperber (1948) and Nemec and Brinkhurst (1987) are not as consistent with our results. We note that our study suggests the genus Stylaria is comprised of two distinct species, Stylaria lacustris and Stylaria fossularis, rather than merely two morphotypes of a single species. Based on our phylogenetic results, we suggest that pigmented eyes evolved only once among naidids but must have been lost multiple times, and that the elongation of the prostomium into a proboscis evolved at least twice independently. The simplest form of fission, architomy (fragmentation), occurs in two of the most basally branching naidid genera, and may represent the plesiomorphic condition for naidids.     

Molecular phylogeny of Trissolcus species (Hymenoptera: Scelionidae)

Trissolcus species (Hymenoptera: Scelionidae) are the most promising biological control agents against sunn pest. The accurate identification of natural enemies is crucial in order to develop successful biological control programs. This paper presents phylogenetic analyses of Trissolcus species based on data sets consisting of 18S, 28S, ITS1, ITS2 and cytochrome oxidase subunit I (COI) genes. The most commonly used genetic loci in Trissolcus species identification is the cytochrome oxidase I gene (COI). Also restriction fragment length polymorphism analyses of PCR amplified COI gene have been developed to discriminate closely related species. We suggest that Trissolcus grandis Thompson and Trissolcus semistriatus Nees split significantly into two different genetic groups while there is another species diverging from T. semistriatus which is decsribed as ‘Trissolcus flavotibialis Kocak & Guz, n. sp.’     

Molecular systematics of polychaetes (Annelida)

Hydrobiologia - Some progress has been made in the field of molecular systematics of polychaetes over the past couple of years. In particular, phylogenetic analyses of sequence data from the 18S...     

The Nearctic species of Orthoplema (Hymenoptera: Ichneumonidae)

Abstract. The species of the genus Orthopelma Taschenburg in North America are reviewed. Members are endoparasites of the cynipids Diastrophus on Rubus and Diplolepis on Rosa. The Nearctic species ar occidentale, califomicum and erythropa , described by Ashmead, ovale Provancher, and the Holarctic species mediator Thunberg. The names coloradense Ashmead and diastrophi Ashmead are newly placed in synonymy with occidentale Ashmead. Relationships of the species are discussed.     

Systematic revision of Nearctic species of Achalcus Loew (Diptera: Dolichopodidae) with comments on their phylogeny, ecology and zoogeography

The species of the genus Achalcus Loew from the Nearctic Region are revised and a key to males and females is provided. Achalcus utahensis (Harmston & Miller) and A. oregonensis (Harmston & Miller) are redescribed, and A. californicus sp.n., A. dytei sp.n. and A. similis sp.n. are described. Together with eight of the nine known Palaearctic species of the genus, they represent a monophyletic species group, which is characterized by the presence of five pairs of dorsocentral bristles and the incorporation of the epandrial setae onto the shaft of the epandrial lobe. Like their Palaearctic congeners, most Nearctic species occur in damp habitats, such as coastal forests and riparian vegetation. Most specimens were collected in the Pacific coastal states from British Columbia to California, but one species occurs in Utah, and one of six species which were not described because males are lacking, was discovered in Ontario.     

Morphological and molecular evidence of the phylogeny of Nereidiform polychaetes (Annelida)

The phylogeny of Nereidiformia is assessed in a parsimony analysis of combined morphological and DNA data, with special focus on previously questioned relationships between Chrysopetalidae and Hesionidae, between Pilargidae and Hesionidae, and the affinities of Hesionides and Microphthalmus. A 660 bp segment of the mtDNA cytochrome c oxidase subunit I gene was sequenced for two chrysopetalids, one nereidid, one pilargid, one pisionid, two hesionids, plus the two questionable hesionids Hesionides arenaria and Microphthalmus sp. Phylogenetic resolution was poor for the cytochrome c oxidase subunit I gene data alone, but the combined analysis yielded partially robust topologies, suggesting that nereids are the sister group to chrysopetalids, and that pilargids, Hesionides and Microphthalmus do not belong within the hesionids     

Molecular phylogeny of Arthrotardigrada (Tardigrada)

Tardigrades are microscopic ecdysozoans with a worldwide distribution covering marine, limnic and terrestrial habitats. They are regarded as a neglected phylum with regard to studies of their phylogeny. During the last decade molecular data have been included in the investigation of tardigrades. However, the marine arthrotardigrades are still poorly sampled due to their relative rarity, difficult identification and minute size even for tardigrades. In the present study, we have sampled various arthrotardigrades and sequenced the 18S and partial 28S ribosomal subunits. The phylogenetic analyses based on Bayesian inference and maximum parsimony inferred Heterotardigrada (Arthrotardigrada + Echiniscoidea) and Eutardigrada to be monophyletic. Arthrotardigrada was inferred to be paraphyletic as the monophyletic Echiniscoidea is included within the arthrotardigrades. The phylogenetic positions of Stygarctidae and Batillipedidae are poorly resolved with low branch support. The Halechiniscidae is inferred to be polyphyletic as the currently recognized Styraconyxinae is not part of the family. Archechiniscus is the sister-group to the Halechiniscidae and Orzeliscus is placed as one of the basal halechiniscids. The phylogeny of the included eutardigrade taxa resembles the current molecular phylogenies. The genetic diversity within Arthrotardigrada is much larger (18S 15.1–26.5%, 28S 7.2–20.7%) than within Eutardigrada (18S 1.0–12.6%, 28S 1.3–8.2%). This can be explained by higher substitution rates in the arthrotardigrades or by a much younger evolutionary age of the sampled eutardigrades.     

Molecular phylogeny and adaptive radiation of the endemic Hawaiian Plantago species (Plantaginaceae)

Insular oceanic islands provide excellent opportunities for the study of evolutionary processes and adaptive radiation. The Hawaiian Plantago radiation comprises six endemic taxa showing considerable inter- and intraspecific morphological and ecological diversity. The rDNA internal (ITS) and external (ETS) transcribed spacers and two recently described chloroplast spacers, ndhF-rpl32 and rpl32-trnL, were sequenced to study phylogenetic relationships within this morphologically complex group. Phylogenetic analysis provided strong evidence for the monophyly of Hawaiian Plantago, suggesting that the lineage arose from a single long-distance dispersal event. Inconsistencies between nuclear and chloroplast phylogenies suggest a history of hybridization. The basal, unresolved dichotomy of the combined phylogeny is consistent with rapid phenotypic diversification of the major lineages early in the history of this group. Speciation has largely occurred allopatrically, with divergence a result of intraisland ecological shifts between bog and woodland habitats and interisland dispersal events. Most interisland colonizations were from older to younger islands with initial colonization of Kaua'i. In our analysis, P. pachyphylla is paraphyletic and taxonomic separation of the distinct morphotypes of this species appears justified. Furthermore, the apparent hybrid ancestry and unique morphology and habitat of the endangered P. princeps var. longibracteata support its recognition at the specific rank.     

On the phylogeny of the Phyllodocidae (Polychaeta Annelida): an alternative

The phylogeny of the Phyllodocidae (Polychaeta Annelida) is examined in an analysis which includes previously unnoticed characters of the nervous system. Concentrating on four problems of importance in understanding the phylogeny of the family, a study of the nervous system demonstrated that: 1. A median antenna, such as that present in species of Eulalia, is not homologous to the nuchal papilla of, for example, Eteone and Phyllodoce; 2. Nuchal organs, presumably found in all phyllodocids, are basically homologous, but four separate types may be recognized; 3. The anterior concentration of the first segments (particularly their tentacular cirri), which is evident in most phyllodocids, is accompanied by different alterations of the ventral nervous system. The polarities of these changes are not self-evident; 4. A study of the ventral nervous system of Eteone reveals that the first apparent segment, bearing two pairs of tentacular cirri, must be regarded as homologous to the second segment of all other phyllodocids. Furthermore, this genus descended from forms in which a segment was present anterior to the first apparent segment, the first two segments possibly bearing tightly packed tentacular cirri. In connection with other characters, this information was used to produce a cladogram, which has some surprising features. The most unexpected result is the prediction that Eteone is the sister group of a taxon containing the genera Paranaitis, Chaetoparia, and Phyllodoce. The results are discussed and compared to those of other investigators.     

Molecular phylogeny of Caloboletus (Boletaceae) and a new species in East Asia

Caloboletus has recently been erected to accommodate Boletus calopus and its allies. Our phylogenetic analyses based on four gene markers (ITS, nrLSU, tef1-α and rpb1) recognized six distinct species within the genus. Morphologically, the genus is characterized by the combination of the yellow hymenophore, smooth spores that are olive-brown in deposit, an interwoven pileipellis, a bluish color-change and a distinctly bitter taste of the context. A new species was described and a key to the six species of Caloboletus is provided. Members of Caloboletus are mainly distributed in subtropical and temperate zones in the Holarctic and are often associated with plants of Pinaceae and Fagaceae.     

Molecular phylogeny of hybridizing species from the genus Spartina Schreb. (Poaceae)

Interspecific hybridization events have been reported in the genus Spartina Schreb. (Poaceae), involving the east American species Spartina alterniflora, and including either introgression (e.g., with the western American Spartina foliosa) or allopolyploid speciation (e.g., with the Euro-African Spartina maritima). Molecular phylogenetic analysis of the genus has been undertaken in order to understand phylogenetic relationships and genetic divergence among these hybridizing species. Twelve Spartina species have been sequenced for two nuclear DNA regions (ITS of ribosomal DNA, and part of the Waxy gene) and one chloroplast DNA spacer (trnT-trnL). Separate and conditional combined phylogenetic analyses using Cynodon dactylon as the outgroup have been conducted. Spartina is composed of two lineages. The first clade includes all hexaploid species: the Euro-African S. maritima (2n = 60), the East-American S. alterniflora (2n = 62) and the West-American S. foliosa (2n = 60). Spartina alterniflora appears as a closely related sister species to S. foliosa. Although belonging to the same lineage, Spartina maritima appears consistently more genetically differentiated from S. alterniflora than S. foliosa. The tetraploid species S. argentinensis (2n = 40) is placed at the base of this first clade according to the Waxy data, but its position is not well resolved by the other sequences. The second well-supported main lineage within genus Spartina includes the other tetraploid American species. Significant incongruence has been encountered between the waxy based tree and both the ITS and trnT-trnL trees concerning the position of S. densiflora, suggesting a possible reticulate evolution for this species. The results agree with hybridization patterns occurring in Spartina: introgression involving closely related species (S. alterniflora and S. foliosa) on one hand, and alloploid speciation involving more differentiated species (S. alterniflora and S. maritima) on the other hand.     

Molecular and morphometric analyses identify new lineages within a large Eumida (Annelida) species complex

We report on two new lineages of the Eumida sanguinea complex from Great Britain and describe one of them as a new species using a multilocus approach, including the mitochondrial DNA COI-5P and the nuclear markers ITS (ITS1, 5.8S rRNA and ITS2) and 28S rRNA. The molecular analysis placed Eumida mackiei sp. nov. in a monophyletic clade with 19.1% (COI), 10.1% (ITS) and 1.7% (28S) mean distance to its nearest neighbour. Molecular diagnoses were also applied to nine lineages within the E. sanguinea complex. This was complemented with morphometric data employing multivariate statistical analysis and the incorporation of statistical dissimilarities against three other described species from the complex. Eumida mackiei sp. nov. can be distinguished from E. notata and E. maia by the larger distance between the eyes and differences in morphometric proportions mainly in the dorsal and ventral cirri as well as in the prostomial appendages. E. sanguinea sensu stricto failed to produce a cluster of its own in the morphometric analysis, probably due to juvenile bias. Integrative taxonomy provided strong evidence to formally describe a new cryptic species that can now be used in biomonitoring or other relevant ecological research.     

Sperm ultrastructure of three Syllinae (Annelida, Phyllodocida) species with considerations on syllid phylogeny and Syllis vittata reproductive biology

Phylogeny of Syllidae is under debate due to new studies based on molecular and morphological data. The noticeable taxonomic diversity of syllids (about 700 listed species) is also mirrored in the array of reproductive strategies as well as in sperm morphology, counting a display of forms already supposed to reflect phylogenetic relationships between the species. The sperm ultrastructure of Syllis gerlachi, S. prolifera and S. vittata is herein presented and compared to the Syllinae species studied previously. Moreover, the egg structure and the gamete allocation within stolons of S. vittata are particularly investigated. Both male germinal cells at different level of maturation and oocytes were found in the same individual of S. vittata, suggesting simultaneous hermaphroditism. The ultrastructural analysis revealed that the observed spermatozoa belong to the ect-aquasperm type resembling those of the similar studied species (Syllis sp., S. pigmentata and S. krohni). Differences in the acrosome structure and nucleus shape are in accordance with a recent phylogenetic reconstruction and suggest a trend in the evolution of spermatozoa in Syllinae toward the development of the apical part. However, further molecular and ultrastructural analyses are needed to support this hypothesis. This is the first record of simultaneous hermaphroditism within Syllinae.     

Molecular phylogeny and morphology reveal a new species of Amyloporia (Basidiomycota) from China

Amyloporia pinea sp. nov. is described and illustrated on the basis of collections from southern China. Morphology and phylogenetic analysis of rDNA ITS sequences support this new species. Morphologically, it is characterized by resupinate, annual basidiocarps, cream to yellowish buff pore surface when fresh, which becomes yellowish brown to clay-buff upon drying, a dimitic hyphal system with clamped generative hyphae and inamyloid skeletal hyphae, fusoid cystidioles, and cylindrical basidiospores; moreover, it causes a brown rot. Molecular phylogeny inferred from ITS sequence data suggested a close relationship between A. pinea and Amyloporia crassa sensu lato. Antrodia subxantha has amyloid skeletal hyphae, and grouped within the Amyloporia clade, hence, it is transferred to Amyloporia, and a new combination Amyloporia subxantha is proposed.