On the changing ecology of Venice lagoon

The amplexial morphology of representative species from all anostracan families is described. Males of the Polyartemiidae and Artemiidae amplex the female's brood pouch. Males of all other families amplex the female's body between the brood pouch and the last pair of legs: a region referred to herein as the `amplexial groove.' The amplexial groove in females of Streptocephalus, Thamnocephalus, Dendrocephalus, Branchinella, and the Branchipodidae is unornamented and females are not separable among the species. Females in the genus Parartemia and the families Chirocephalidae and Linderiellidae have morphological characters within their amplexial region that complement the ornamentation of the male's second antennae, creating a `lock and key' fit unique to each species.     

Affinities among anostracan (Crustacea: Branchiopoda) families inferred from phylogenetic analyses of multiple gene sequences

To gain insights into the relationships among anostracan families, molecular phylogenetic analyses were performed on nuclear (28S D1-D3 ribosomal DNA) and mitochondrial (16S rDNA, COI) gene regions for representatives of seven families and an outgroup. Data matrices used in the analyses included 951 base pairs (bp) of aligned sequences for 28S, 465 bp for 16S, and 658 bp (219 amino acids) for COI. Maximum-parsimony and maximum-likelihood methods were used to construct phylogenetic trees, enabling the evaluation of both previous hypotheses of taxonomic relationships among families based on morphology, and of the relative merits of independent versus simultaneous analyses of multiple data sets for phylogeny construction. Data from various combinations of the gene regions produced relatively congruent patterns of phylogenetic affinity. In most analyses, two monophyletic groups were resolved: one cluster included the families Polyartemiidae, Chirocephalidae, Branchinectidae, Streptocephalidae, and Thamnocephalidae, while the other contained the Artemiidae and Branchipodidae. Comparative analyses showed that combining gene regions in a single matrix generally resulted in increased resolution and support for each cluster relative to those obtained from single-gene analyses. Statistical tests demonstrated that morphology-based hypotheses of relationships among families had poorer support than those determined from molecular data, reflecting the homoplasy in characters used to differentiate families.     

Phylogenetic position of the adeleorinid coccidia (Myzozoa, Apicomplexa, Coccidia, Eucoccidiorida, Adeleorina) inferred using 18S rDNA sequences

Investigating the evolutionary relationships of the major groups of Apicomplexa remains an important area of study. Morphological features and host-parasite relationships continue to be important in the systematics of the adeleorinid coccidia (suborder Adeleorina), but the systematics of these parasites have not been well-supported or have been constrained by data that were lacking or difficult to interpret. Previous phylogenetic studies of the Adeleorina have been based on morphological and developmental characters of several well-described species or based on nuclear 18S ribosomal DNA (rDNA) sequences from taxa of limited taxonomic diversity. Twelve new 18S rDNA sequences from adeleorinid coccidia were combined with published sequences to study the molecular phylogeny of taxa within the Adeleorina and to investigate the evolutionary relationships of adeleorinid parasites within the Apicomplexa. Three phylogenetic methods supported strongly that the suborder Adeleorina formed a monophyletic clade within the Apicomplexa. Most widely recognized families within the Adeleorina were hypothesized to be monophyletic in all analyses, although the single Hemolivia species included in the analyses was the sister taxon to a Hepatozoon sp. within a larger clade that contained all other Hepatozoon spp. making the family Hepatozoidae paraphyletic. There was an apparent relationship between the various clades generated by the analyses and the definitive (invertebrate) host parasitized and, to lesser extent, the type of intermediate (vertebrate) host exploited by the adeleorinid parasites. We conclude that additional taxon sampling and use of other genetic markers apart from 18S rDNA will be required to better resolve relationships among these parasites.     

基于18S rDNA序列的蝽次目(半翅目：异翅亚目)

利用18SrDNA分子约1 912 bp的序列对蝽次目21个科53个种进行系统发育分析。运用MP法、ML法和NJ法分析后的结果表明:蝽次目的单系性得到很高的支持;扁蝽总科成为毛点类的姐妹群;毛点类基本确定为两大分支:一支包含蝽总科和红蝽总科;另一支主要由长蝽总科、缘蝽总科和南蝽总科组成;长蝽总科和缘蝽总科都是多系;长蝽总科中,跷蝽科和皮蝽科的关系最近,构成姐妹群,位于整个毛点类的基部;与长蝽总科中另外两个科长蝽科和地长蝽科的关系很远。说明利用18SrDNA分子对研究蝽次目的系统发育关系是适合的,能够重建蝽次目;扁蝽总科和蝽总科单系性的结果与形态学的研究以及Li et al (2005)的研究一致;但较Li et al(2005)的研究更进一步把红蝽总科从广义的缘蝽总科中分出来;并建议皮蝽科作为一个独立的总科更合适。     

Phylogeny of Myrmeleontiformia based on larval morphology (Neuropterida: Neuroptera)

The suborder Myrmeleontiformia is a derived lineage of lacewings (Insecta: Neuroptera) including the families Psychopsidae, Nemopteridae, Nymphidae, Ascalaphidae and Myrmeleontidae. In particular, Myrmeleontidae (antlions) are the most diverse neuropteran family, representing a conspicuous component of the insect fauna of xeric environments. We present the first detailed quantitative phylogenetic analysis of Myrmeleontiformia, based on 107 larval morphological and behavioural characters for 36 genera whose larvae are known (including at least one representative of all the subfamilies of the suborder). Four related families were used as outgroups to polarize character states. Phylogenetic analyses were conducted using both parsimony and Bayesian methods. The reconstructions resulting from our analyses corroborate the monophyly of Myrmeleontiformia. Within this clade, Psychopsidae are recovered as the sister family to all the remaining taxa. Nemopteridae (including both subfamilies Nemopterinae and Crocinae) are recovered as monophyletic and sister to the clade comprising Nymphidae + (Myrmeleontidae + Ascalaphidae). Nymphidae consist of two well‐supported clades corresponding to the subfamilies Nymphinae and Myiodactylinae. Our results suggest that Ascalaphidae may not be monophyletic, as they collapse into an unresolved polytomy under the Bayesian analysis. In addition, the recovered phylogenetic relationships diverge from the traditional classification scheme for ascalaphids. Myrmeleontidae are reconstructed as monophyletic, with the subfamilies Stilbopteryginae, Palparinae and Myrmeleontinae. We retrieved a strongly supported clade comprising taxa with a fossorial habit of the preimaginal instars, which represents a major antlion radiation, also including the monophyletic pit‐trap building species.     

Molecular phylogenetics of the spider infraorder Mygalomorphae using nuclear rRNA genes (18S and 28S): conflict and agreement with the current system of classification

Mygalomorph spiders, which include the tarantulas, trapdoor spiders, and their kin, represent one of three main spider lineages. Mygalomorphs are currently classified into 15 families, comprising roughly 2500 species and 300 genera. The few published phylogenies of mygalomorph relationships are based exclusively on morphological data and reveal areas of both conflict and congruence, suggesting the need for additional phylogenetic research utilizing new character systems. As part of a larger combined evidence study of global mygalomorph relationships, we have gathered approximately 3.7 kb of rRNA data (18S and 28S) for a sample of 80 genera, representing all 15 mygalomorph families. Taxon sampling was particularly intensive across families that are questionable in composition-Cyrtaucheniidae and Nemesiidae. The following primary results are supported by both Bayesian and parsimony analyses of combined matrices representing multiple 28S alignments: (1) the Atypoidea, a clade that includes the families Atypidae, Antrodiaetidae, and Mecicobothriidae, is recovered as a basal lineage sister to all other mygalomorphs, (2) diplurids and hexathelids form a paraphyletic grade at the base of the non-atypoid clade, but neither family is monophyletic in any of our analyses, (3) a clade consisting of all sampled nemesiids, Microstigmata and the cyrtaucheniid genera Kiama, Acontius, and Fufius is consistently recovered, (4) other sampled cyrtaucheniids are fragmented across three separate clades, including a monophyletic North American Euctenizinae and a South African clade, (5) of the Domiothelina, only idiopids are consistently recovered as monophyletic; ctenizids are polyphyletic and migids are only weakly supported. The Domiothelina is not monophyletic. The molecular results we present are consistent with more recent hypotheses of mygalomorph relationship; however, additional work remains before mygalomorph classification can be formally reassessed with confidence-increased taxonomic sampling and the inclusion of additional character systems (more genes and morphology) are required.     

A molecular phylogeny of the Odonata (Insecta)

Abstract. We estimated the phylogeny of the order Odonata, based on sequences of the nuclear ribosomal genes 5.8 S, 18S, and ITS1 and 2. An 18S‐only analysis resolved deep relationships well: the order Odonata, as well as suborders Zygoptera and Epiprocta (Anisoptera + Epiophlebia), emerged as monophyletic. Some other deep clades resolved well, but support for more recently diverged clades was generally weak. A second, simultaneous, analysis of the 5.8S and 18S genes with the intergenic spacers ITS1 and 2 resolved some recent branches better, but appeared less reliable for deep clades with, for example, suborder Anisoptera emerging as paraphyletic and Epiophlebia superstes recovered as an Anisopteran, embedded within aeshnoid‐like anisopterans and sister to the cordulegastrids. Most existing family levels in the Anisoptera were confirmed as monophyletic clades in both analyses. However, within the corduliids that form a major monophyletic clade with the Libellulidae, several subclades were recovered, of which at least Macromiidae and Oxygastridae are accepted at the family level. In the Zygoptera, the situation is complex. The lestid‐like family groups (here called Lestomorpha) emerged as sister taxon to all other zygopterans, with Hemiphlebia sister to all other lestomorphs. Platystictidae formed a second monophylum, subordinated to lestomorphs. At the next level, some traditional clades were confirmed, but the tropical families Megapodagrionidae and Amphipterygidae were recovered as strongly polyphyletic, and tended to nest within the clade Caloptera, rendering it polyphyletic. Platycnemididae were also non‐monophyletic, with several representatives of uncertain placement. Coenagrionids were diphyletic. True Platycnemididae and non‐American Protoneurids are closely related, but their relationship to the other zygopterans remains obscure and needs more study. New World protoneurids appeared relatively unrelated to old world + Australian protoneurids. Several recent taxonomic changes at the genus level, based on morphology, were confirmed, but other morphology‐based taxonomies have misclassified taxa considered currently as Megapodagrionidae, Platycnemididae and Amphipterygidae and have underestimated the number of family‐level clades.     

Galaziella baikalensis, a new genus and species of chirocephalid (Crustacea: Branchiopoda: Anostraca) from Russia and the zoogeography of East Asian Anostraca

Galaziella baikalensis gen. et sp. nov. is described from Olkhon Island, Lake Baikal, Russia. The genus is assigned to the family Chirocephalidae Daday, 1910, on the basis of the following features: the male has two-segmented antenna, its basal segment bearing two leaf-shaped antennal appendages, all thoracopods with two distinctly divided pre-epipodites, and genital segments containing two clearly defined seminal vesicles. Galaziella is well distinguished from other genera of the family by the apical part of the penes, armed with "two spiniform processes" at each apex, instead of a single spine or toothed plate. Such male genital processes have not yet been found in Chirocephalidae, so that the diagnosis of the family is revised and two sub-families are proposed herein. Up to the present, 10 species belonging to 7 genera, including Galaziella baikalensis, and 5 families of Anostraca – Artemiidae, Branchinectidae, Branchipodidae, Chirocephalidae, and Thamnocephalidae – have been found in East Asia and its adjacent areas, including the Russian Far East, Mongolia, China, Korea, and Japan. The list includes all synonymic taxa. A distribution map and a key to the East Asian species of the family Chirocephalidae are provided. Received: November 22, 1999 / Accepted: May 2, 2000     

A molecular phylogeny of heterodont bivalves (Mollusca: Bivalvia: Heterodonta): new analyses of 18S and 28S rRNA genes

A new molecular phylogeny is presented for the highly diverse, bivalve molluscan subclass Heterodonta. The study, the most comprehensive for heterodonts to date, used new sequences of 18S and 28S rRNA genes for 103 species from 49 family groups with species of Palaeoheterodonta (Trigoniidae, Margaritiferidae and Unionidae) as outgroups. Results confirm previous analyses that the Carditidae/Astartidae/Crassatellidae clade is basal to all other heterodonts including Anomalodesmata (often classified as a separate subclass or order). Thyasiroidea occupy a near basal position between the Crassatelloidea and Anomalodesmata. Lucinidae form a well‐supported monophyletic group distinct from Thyasiridae and Ungulinidae. The Solenoidea and Hiatelloidea link as sister groups distant from the Tellinoidea and Myoidea, respectively, where they had been previously associated. The position of the Gastrochaenidae is unstable but does not group with myoidean taxa. Species of four families of Galeommatoidea form a clade that also includes Sportellidae of the Cyamioidea. The Cardioidea and Tellinoidea form highly supported, long branched, individual clades but group as sister taxa. A major clade including Veneroidea, Mactroidea, Myoidea and other families is given the unranked name Neoheterodontei. There is no support for a separate order Myoida (Myoidea and Pholadoidea). Dreissenidae group within the clade including Myidae, Corbulidae, Pholadidae and Teredinidae. The Corbiculoidea is confirmed as polyphyletic with the Sphaeriidae and Corbiculidae forming separate clades within the Neoheterodontei; Corbiculidae grouping with the Glauconomidae. Hemidonacidae are unrelated to the Cardiidae, as previously proposed, but nest within the Neoheterodontei. The Gaimardiidae group near to the Ungulinidae and not with Cyamioidea where most recently classified. The family Ungulinidae, previously classified in the Lucinoidea, forms a well‐supported clade within the Neoheterodontei and is elevated to superfamily rank — Ungulinoidea. The monophyletic status of Glossoidea, Arcticoidea and Veneroidea is unconfirmed. A brief review of the fossil record of the heterodonts indicates that the basal clades of Crassatelloidea, Anomalodesmata and Lucinoidea diverged very early in the Lower Palaeozoic. Other groups such as the Hiatelloidea, Solenoidea, Gastrochaenidae probably were of late Palaeozoic origins. The Cardioidea and Tellinoidea originated in the Triassic while major groups of Neoheterodontei radiated in the Late Mesozoic. The phylogenetic position of the Thyasiroidea and Galeommatoidea suggests a longer fossil history than has so far been recognized.     

Phylogenetic relationships among families of the Scaphopoda (Mollusca)

Phylogenetic relationships among families in the molluscan class Scaphopoda were analysed using morphological characters and cladistic parsimony methods. A maximum parsimony analysis of 34 discrete characters, treated as unordered and equally weighted, from nine ingroup terminal taxa produced a single most parsimonious tree; supplementary analyses of tree length frequency distribution and Bremer support indices indicate a strong phylogenetic signal from the data and moderate to minimally supported clades. The traditional major division of the class, the orders Dentaliida and Gadilida, is supported as both taxa are confirmed as monophyletic clades. Within the Dentaliida, two clades are recognized, the first comprised of the families Dentaliidae and Fustiariidae, the second of the Rhabdidae and Calliodentaliidae; together, these groups comprise a third clade, which has the Gadilinidae as sister. Within the Gadilida, a nested series of relationships is found among [Entalinidae, [Pulsellidae, [Wemersoniellidae, Gadilidae]]]. These results lend cladistic support to earlier hypotheses of shared common ancestry for some families, but are at variance with other previous hypotheses of evolution in the Scaphopoda. Furthermore, analysis of constituent Gadilinidae representatives provide evidence for paraphyly of this family. The relationships supported here provide a working hypothesis that the development of new characters and greater breadth of taxonomic sampling can test, with a suggested primary goal of establishing monophyly at the family level.     

Phylogeny of coral-inhabiting barnacles (Cirripedia; Thoracica; Pyrgomatidae) based on 12S, 16S and 18S rDNA analysis

The traditional phylogeny of the coral-inhabiting barnacles, the Pyrgomatidae, is based on morphological characteristics, mainly of the hard parts. It has been difficult to establish the phylogenetic relationships among Pyrgomatidae because of the apparent convergence of morphological characteristics, and due to the use of non-cladistic systematics, which emphasize ancestor-descendant relationships rather than sister-clade relationships. We used partial sequences of two mithochondrial genes, 12S rDNA and 16S rDNA, and a nuclear gene, 18S rDNA, to infer the molecular phylogeny of the pyrgomatids. Our phylogenetic results allowed us to reject previous classifications of Pyrgomatidae based on morphological characteristics. Our results also suggested the possibility of paraphyly of the Pyrgomatidae. The hydrocoral barnacle Wanella is not found on the same clade as the other pyrgomatids, but rather, with the free-living balanids. The basal position of Megatrema and Ceratoconcha is supported. The archeaobalanid Armatobalanus is grouped with Cantellius at the base of the Indo-Pacific pyrgomatines. Fusion of the shell plate and modification of the opercular valves are homoplasious features that occurred more than three times on different clades. The monophyly of the "Savignium" group, comprising four nominal genera, is also not supported, and the different taxa are placed on different clades.     

MULTIGENE ANALYSES OF PHOTOSYNTHETIC EUGLENOIDS AND NEW FAMILY,PHACACEAE (EUGLENALES)1

Bayesian and maximum‐likelihood (ML) analyses of the combined multigene data (nuclear SSU rDNA, and plastid SSU and LSU rDNA) were conducted to evaluate the phylogeny of photosynthetic euglenoids. The combined data set consisted of 108 strains of photosynthetic euglenoids including a colorless sister taxon. Bayesian and ML analyses recovered trees of almost identical topology. The results indicated that photosynthetic euglenoids were divided into two major clades, the Euglenaceae clade (Euglena, Euglenaria, Trachelomonas, Strombomonas, Monomorphina, Cryptoglena, Colacium) and the Phacaceae clade (Phacus, Lepocinclis, Discoplastis). The Euglenaceae clade was monophyletic with high support and subdivided into four main clades: the Colacium, the Strombomonas and Trachelomonas, the Cryptoglena and Monomorphina, and the Euglena and Euglenaria clades. The genus Colacium was positioned at the base of the Euglenaceae and was well supported as a monophyletic lineage. The loricate genera (Strombomonas and Trachelomonas) were located at the middle of the Euglenaceae clade and formed a robust monophyletic lineage. The genera Cryptoglena and Monomorphina also formed a well‐supported monophyletic clade. Euglena and the recently erected genus Euglenaria emerged as sister groups. However, Euglena proxima branched off at the base of the Euglenaceae. The Phacaceae clade was also a monophyletic group with high support values and subdivided into three clades, the Discoplastis, Phacus, and Lepocinclis clades. The genus Discoplastis branched first, and then Phacus and Lepocinclis emerged as sister groups. These genera shared a common characteristic, numerous small discoid chloroplasts without pyrenoids. These results clearly separated the Phacaceae clade from the Euglenaceae clade. Therefore, we propose to limit the family Euglenaceae to the members of the Euglena clade and erect a new family, the Phacaceae, to house the genera Phacus, Lepocinclis, and Discoplastis.     

A preliminary phylogeny of the Pentatomomorpha (Hemiptera: Heteroptera) based on nuclear 18S rDNA and mitochondrial DNA sequences

Pentatomomorpha is the second suborder in size only to Cimicomorpha in Heteroptera. However, the phylogenetic relationships among members of the suborder are not well established. Sequences from partial nuclear ribosomal 18S gene and mitochondrial COX1 gene were analyzed separately and in combination to generate a preliminary molecular phylogeny of Pentatomomorpha based on 40 species representing 17 putative families. Analyses of the combined sequence data provided a better-resolved and more robust hypothesis of Pentatomomorpha phylogeny than did separate analyses of the individual genes. The phylogenies were mostly congruent with morphological studies. Results strongly supported the monophyly of the infraorder Pentatomomorpha, and the placement of Aradoidea as sister to Trichophora. The monophyletic Trichophora was grouped into two major lineages, one being the superfamily Pentatomoidea, and the other comprising Lygaeoidea, Coreoidea, and Pyrrhocoroidea. The analysis of the ML and ME trees of combined dataset supported the monophyletic Pentatomoidea. In all analysis the Pyrrhocoroidea was polyphyletic; the monophyletic Lygaeoidea was supported only in the analysis of ME tree, and Coreoidea was polyphyletic except in the MP tree of combined dataset. The molecular and morphylogical data both indicated that the family Coreoidae should be revised subsequently. Our phylogenetic results suggested that the COX1 segment alone might not be an optimal molecular marker for the phylogeny of Pentatomomorpha.     

Paraphyly of Homoptera and Auchenorrhyncha inferred from 18S rDNA nucleotide sequences

Evolutionary affiliations of eighteen families of Hemiptera (s.l.) are inferred using molecular phylogenetic analysis of nucleotide (nt) sequences of 18S rDNAs. Exemplar taxa include: Archaeorrhyncha (=Fulgoromorpha): flatid, issid, dictyopharid, cixiid and delphacid; Prosorrhyncha (=Heteropterodea): Peloridiomorpha (=Coleorhyncha) -peloridiid, Heteroptera gerrid, lygaeid and mirid; Clypeorrhyncha [=extant (monophyletic) cicadomorphs]: cicadid, cercopoids (cercopid, aphrophorid), membracid and cicadellids (deltocephaline and cicadelline); and Sternorrhyncha: psyllid, aleyrodid, diaspidid and aphid. Analysed sequences encompass a region beginning ?550 nucleotides (nts) from the 5'-end to ?200 nts upstream from the 3'-end of the gene [?1150 base pairs (bp) in euhemipteran to >1400 bp in sternorrhynchan taxa]. Maximum parsimony and bootstrap analyses (PAUP) identify four principal hemipteran clades, Stenorrhyncha, Clypeorrhyncha, Archaeorrhyncha and Prosorrhyncha. These lineages are identified by synapomorphies distributed throughout the gene. Sternorrhyncha is a sister group to all other Hemiptera (i.e. Euhemiptera sensu Zrzavy), rendering Homoptera paraphyletic. Within Euhemiptera, clades Clypeorrhyncha, Archaeorrhyncha, Prosorrhyncha and Heteroptera are supported by one, three, two and three synapomorphic sites, respectively. There is equitable parsimonious inference for Archaeorrhyncha as the sister group to Prosorrhyncha (Neoherriiptera sensu Sorensen et al.) or Clypeorrhyncha, in either case rendering Auchenorrhyncha paraphyletic. Neohemiptera is supported by one synapomorphy. Within Clypeorrhyncha, clade cicada + cercopoids is the sister group of the clade cicadellids + membracid (Membracoidea sensu Dietrich & Deitz). Among archaeorrhynchans, clade delphacid + cixiid is the sister group of the clade dictyopharid + flatid + issid. Within Prosorrhyncha, the peloridiid is sister to the Heteroptera. Within Heteroptera, gerrid is the sister group of the clade mirid + lygaeid (Panheteroptera sensu Schuh). Based on secondary structure of synonymous 18S rRNA, two synapomorphies each of Sternorrhyncha, Prosorrhyncha and Heteroptera are compensatory substitutions on stem substructures. All other synapomorphies identifying major lineages of Hemiptera are noncompensatory substitutions on either bulges or stems. Short basal internodal distances suggest radiation of hemipteran lineages at the suborder level occurred rapidly. Morphological, palaeoentomological and eco-evolutionary factors supporting the 18S rDNA-based phylogenetic tree are discussed.     

PHYLOGENY OF THE BATRACHOSPERMALES (RHODOPHYTA) INFERRED FROM rbcL AND 18S RIBOSOMAL DNA GENE SEQUENCES

The sequence data from the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase ( rbc L) gene and 18S ribosomal DNA (small subunit) of taxa in the freshwater rhodophyte order Batrachospermales were used to construct phylogenetic hypotheses. Taxa examined in this study represent four families, eight genera, and six sections of the genus Batrachospermum . In addition, Rhododraparnaldia oregonica Sheath, Whittick et Cole, was included in the analysis because it shares particular ultrastructural, reproductive, and morphological characteristics with members of the Batrachospermales and Acrochaetiales. The trees generated from each gene, as well as a combined data set, were largely congruent. Rhododraparnaldia consistently occurs on an early branch within the Acrochaetiales – Palmariales clade and does not appear to be a member of the Batrachospermales. In addition, Thorea violacea Bory de St. Vincent was not closely related to the other taxa of the Batrachospermales in all trees and hence the family Thoreaceae does not appear to be a natural grouping within this order. All other taxa analyzed, which are presently classified within this order, formed a monophyletic clade in most analyses. Psilosiphon scoparium Entwisle was not closely allied with the taxa of the Lemaneaceae, lending support to the newly proposed family Psilosiphonaceae. Sequence data from the remaining taxa of the Lemaneaceae support the concept of a derived monophyletic clade. The genus Batrachospermum appears to comprise many morphologically similar but distantly related taxa, which will need further investigation to resolve their taxonomic status. Tuomeya, Sirodotia and Nothocladus are retained at the generic level until further data are obtained.     

Monophyly of the family Desmoscolecidae (Nematoda,Demoscolecida) and Its Phylogenetic position inferred from 18S rDNA sequences

To infer the monophyletic origin and phylogenetic relationships of the order Desmoscolecida, a unique and puzzling group of mainly free-living marine nematodes, we newly determined nearly complete 18S rDNA sequences for six marine desmoscolecid nematodes belonging to four genera (Desmoscolex, Greeffiella, Tricoma and Paratricoma). Based on the present data and those of 72 nematode species previously reported, the first molecular phylogenetic analysis focusing on Desmoscolecida was done by using neighbor joining (NJ), maximum parsimony (MP), maximum likelihood (ML) and Bayesian inference (BI) methods. All four resultant trees consistently and strongly supported that the family Desmoscolecidae forms a monophyletic group with very high node confidence values. The monophyletic clade of desmocolecid nematodes was placed as a sister group of the clade including some members of Monhysterida and Araeolaimida, Cyartonema elegans (Cyartonematidae) and Terschellingia longicaudata (Linhomoeidae) in all the analyses. However, the present phylogenetic trees do not show any direct attraction between the families Desmoscolecidae and Cyartonematidae. Within the monophyletic clade of the family Desmoscolecidae in all of the present phylogenetic trees, there were consistently observed two distinct sub-groups which correspond to the subfamilies Desmoscolecinae [Greeffiella sp. + Desmoscolex sp.] and Tricominae [Paratricoma sp. + Tricoma sp].     

Molecular phylogeny of Laetiporus and other brown rot polypore genera in North America

Phylogenetic relationships were investigated among North American species of Laetiporus, Leptoporus, Phaeolus, Pycnoporellus and Wolfiporia using ITS, nuclear large subunit and mitochondrial small subunit rDNA sequences. Members of these genera have poroid hymenophores, simple septate hyphae and cause brown rots in a variety of substrates. Analyses indicate that Laetiporus and Wolfiporia are not monophyletic. All North American Laetiporus species formed a well supported monophyletic group (the "core Laetiporus clade" or Laetiporus s.s.) with the exception of L. persicinus, which showed little affinity for any genus for which sequence data are available. Based on data from GenBank, the southern hemisphere species L. portentosus also fell well outside the core Laetiporus clade. Wolfiporia dilatohypha was found to represent a sister group to the core Laetiporus clade. Isolates of Phaeolus, Pycnoporellus and members of the core Laetiporus clade all fell within the Antrodia clade of polypores, while Leptoporus mollis and Laetiporus portentosus fell within the phlebioid clade of polypores. Wolfiporia cocos isolates also fell in the Antrodia clade, in contrast to previous studies that placed W. cocos in the core polyporoid clade. ITS analyses resolved eight clades within Laetiporus s.s., three of which might represent undescribed species. A combined analysis using the three DNA regions resolved five major clades within Laetiporus s.s.: a clade containing conifer-inhabiting species ("Conifericola clade"), a clade containing L. cincinnatus ("Cincinnatus clade"), a clade containing L. sulphureus s.s. isolates with yellow pores ("Sulphureus clade I"), a clade containing L. sulphureus s.s. isolates with white pores ("Sulphureus clade II") and a clade containing L. gilbertsonii and unidentified isolates from the Caribbean ("Gilbertsonii clade"). Although there is strong support for groups within the core Laetiporus clade, relationships among these groups remain poorly resolved.     

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.     

Dumontia oregonensis n. fam., n. gen., n. sp., a cladoceran representing a new family of `Water-fleas' (Crustacea,Anomopoda) from U.S.A., with notes on the classification of the Order Anomopoda

Dumontia oregonensis, a cladoceran representing a new family in the Order Anomopoda is described from rain pools in the Agate Desert, Oregon, U.S.A. The proposed family, Dumontiidae, is the newest family within Anomopoda that is not just a reshuffling of already-known species. The general appearance of this novel cladoceran is similar to that of members of the family Macrothricidae. However, a detailed examination of the trunk limbs, particularly of the second pair of limbs, showed that the new species lacks the scraper-setae typically observed in all members of the recently erected suborder Radopoda, to which macrothricids belong. Instead, limb morphology suggests a closer relation of Dumontiidae to the family Daphniidae. Dumontiidae appears to be a `missing' link between the suborder Radopoda and the `non-radopodid' anomopods. The families Daphniidae, Ilyocryptidae, Bosminidae, Moinidae and the new Dumontiidae are similar in that they lack of typical radopodid setae on the second pair of trunk limbs. Further studies on the limb morphology of non-radopodid cladocerans are required to solve the phylogenetic relationships among the members of the order Anomopoda.