Polyphyly of Lordiphosa and its relationships in Drosophilinae (Diptera: Drosophilidae)

The phylogenetic relationships of Lordiphosa and some taxa in Drosophilinae were analysed on the basis of a total of forty‐one selected drosophilid species. These included eighteen species of five Lordiphosa species‐groups as the main target, twenty‐three species representative of the major drosophiline ingroup taxa and four species of Steganinae as outgroup. Sixty‐eight morphological characters of adults were subjected to cladistic analysis. From the results it is concluded that Lordiphosa is polyphyletic; the Lo. tenuicauda species‐group and genus Nesiodrosophila form a single monophyletic group; Lordiphosa proper (i.e. Lordiphosa spp. minus the tenuicauda group) comprises another monophyletic group; within Lordiphosa proper the fenestrarum, nigricolor and denticeps groups are all monophyletic, but monophyly of the miki group is not strongly supported; genera Hirtodrosophila and Scaptomyza and subgenus Sophophora are all monophyletic; and within Drosophilinae, genus Scaptodrosophila is the first to have split from the main lineage, but the branching order of other clades, Chymomyza, Lordiphosa proper, Sophophora, Hirtodrosophila, Nesiodrosophila+ Lo. tenuicauda group, Scaptomyza, Dorsilopha and subgenus Drosophila, remains unresolved. The topology of maximum parsimony cladograms suggests that Lordiphosa proper lies close to Sophophora as proposed previously, although its phylogenetic position could not be determined conclusively. By contrast, bootstrap values tended to contradict another hypothesis that Lordiphosa and Scaptomyza are sister groups.     

Erratic Evolution of Glycerol-3-Phosphate Dehydrogenase in Drosophila,Chymomyza, and Ceratitis

We have studied the evolution of Gpdh in 18 fruitfly species by sequencing 1,077 nucleotides per species on average. The region sequenced includes four exons coding for 277 amino acids and three variable-length introns. Phylogenies derived by a variety of methods confirm that the nominal genus Zaprionus belongs within the genus Drosophila, whereas Scaptodrosophila and Chymomyza are outside. The rate of GPDH evolution is erratic. The rate of amino acid replacements in a lineage appears to be 1.0 × 10⁻¹⁰/site/year when Drosophila species are considered (diverged up to 55 million years ago), but becomes 2.3 × 10⁻¹⁰ when they are compared to Chymomyza species (divergence around 60 My ago), and 4.6 × 10⁻¹⁰ when species of those two genera are compared with the medfly Ceratitis capitata (divergence around 100 My ago). In order to account for these observations, the rate of amino acid replacement must have been 15 or more times greater in some lineages and at some times than in others. At the nucleotide level, however, Gpdh evolves in a fairly clockwise fashion. Received: 13 June 1996 / Accepted: 16 August 1996     

Phylogenetic Position of the Subgenus Lordiphosa of the Genus Drosophila (Diptera: Drosophilidae) Inferred from Alcohol Dehydrogenase (Adh) Gene Sequences

We analyzed the phylogenetic relationship between the species of Lordiphosa and other Drosophilidae using alcohol dehydrogenase (Adh) gene sequences. The phylogenetic trees consistently show that the four species Drosophila kurokawai, D. collinella, D. stackelbergi, and D. clarofinis, which include three species groups of Lordiphosa, form a monophyletic clade. This clade is placed as a sister group to the willistoni and saltans groups of Sophophora. On the other hand, three species of Lordiphosa, D. tenuicauda, D. pseudotenuicauda, and D. acutissima, all of which belong to the tenuicauda group, are not shown to be related to the major Lordiphosa lineage. In the phylogenetic trees, these species are included into the clade comprised of Drosophila and Hirtodrosophila, although it remains uncertain whether the tenuicauda group is a monophyletic group or not. These results indicate that Lordiphosa is polyphyletic and that most of the members of the subgenus have a close relationship to the neotropical groups of Sophophora. The above conclusion is compatible with the hypothesis of Okada (Mushi [1963] 37:79–100) and Lastovka and Máca (Acta Ent Bohemoslov [1978] 75:404–420) that Lordiphosa is most closely related to Sophophora; in contrast, our results contradict the hypothesis of Grimaldi (Bull Am Mus Nat Hist [1990] 197:1–139) that Lordiphosa is a sister group to the genus Scaptomyza. Received: 12 May 1999 / Accepted: 14 April 2000     

Mitochondrial DNA Phylogeny of the Family Cichlidae: Monophyly and Fast Molecular Evolution of the Neotropical Assemblage

A mitochondrial DNA (mtDNA) phylogeny of cichlid fish is presented for the most taxonomically inclusive data set compiled to date (64 taxa). 16S rDNA data establish with confidence relationships among major lineages of cichlids, with a general pattern congruent with previous morphological studies and less inclusive molecular phylogenies based on nuclear genes. Cichlids from Madagascar and India are the most basal groups of the family Cichlidae and sister to African–Neotropical cichlids. The cichlid phylogeny suggests drift-vicariance events, consistent with the fragmentation of Gondwana, to explain current biogeographic distributions. Important phylogenetic findings include the placement of the controversial genus Heterochromis basal among African cichlids, the South American genus Retroculus as the most basal taxon of the Neotropical cichlid assemblage, and the close relationship of the Neotropical genera Cichla with Astronotus rather than with the crenicichlines. Based on a large number of South American genera, the Neotropical cichlids are defined as a monophyletic assemblage and shown to harbor significantly higher levels of genetic variation than their African counterparts. Relative rate tests suggest that Neotropical cichlids have experienced accelerated rates of molecular evolution. But these high evolutionary rates were significantly higher among geophagine cichlids. Received: 18 September 1998 / Accepted: 16 December 1998     

Phylogeny, Genome Evolution, and Host Specificity of Single-Stranded RNA Bacteriophage (Family Leviviridae)

Bacteriophage of the family Leviviridae have played an important role in molecular biology where representative species, such as Qβ and MS2, have been studied as model systems for replication, translation, and the role of secondary structure in gene regulation. Using nucleotide sequences from the coat and replicase genes we present the first statistical estimate of phylogeny for the family Leviviridae using maximum-likelihood and Bayesian estimation. Our analyses reveal that the coliphage species are a monophyletic group consisting of two clades representing the genera Levivirus and Allolevivirus. The Pseudomonas species PP7 diverged from its common ancestor with the coliphage prior to the ancient split between these genera and their subsequent diversification. Differences in genome size, gene composition, and gene expression are shown with a high probability to have changed along the lineage leading to the Allolevivirus through gene expansion. The change in genome size of the Allolevivirus ancestor may have catalyzed subsequent changes that led to their current genome organization and gene expression. Received: 3 March 2000 / Accepted: 17 October 2000     

Selection and Methionine Accumulation in the Fat Body Protein 2 Gene (FBP2), a Duplicate of the Drosophila Alcohol Dehydrogenase (ADH) Gene

The Drosophila fat body protein 2 gene (Fbp2) is an ancient duplication of the alcohol dehydrogenase gene (Adh) which encodes a protein that differs substantially from ADH in its methionine content. In D. melanogaster, there is one methionine in ADH, while there are 51 (20% of all amino acids) in FBP2. Methionine is involved in 46% of amino acid replacements when Fbp2 DNA sequences are compared between D. melanogaster and D. pseudoobscura. Methionine accumulation does not affect conserved residues of the ADH-ADH^r-FBP2 multigene family. The multigene family has evolved by replacement of mildly hydrophobic amino acids by methionine with no apparent reversion. Its short-term evolution was compared between two Drosophila species, while its long-term evolution was compared between two genera belonging respectively to acalyptrate and calyptrate Diptera, Drosophila and Sarcophaga. The pattern of nucleotide substitution was consistent with an independent accumulation of methionines at the Fbp2 locus in each lineage. Under a steady-state model, the rate of methionine accumulation was constant in the lineage leading to Drosophila, and was twice as fast as that in the calyptrate lineage. Substitution rates were consistent with a slight positive selective advantage for each methionine change in about one-half of amino acid sites in Drosophila. This shows that selection can potentially account for a large proportion of amino acid replacements in the molecular evolution of proteins. Received: 12 December 1994 / Accepted: 15 April 1996     

Analysis of Ribosomal RNA Genes Suggests That Trypanosomes Are Monophyletic

To further investigate the phylogeny of protozoa from the order Kinetoplastida we have sequenced the small subunit (SSU) and a portion of the large subunit (LSU) nuclear rRNA genes. The SSU and LSU sequences were determined from a lizard trypanosome, Trypanosoma scelopori and a bodonid, Rhynchobodo sp., and the LSU sequences were determined from an insect trypanosomatid, Crithidia oncopelti, and a bodonid, Dimastigella trypaniformis. Contrary to previous results, in which trypanosomes were found to be paraphyletic, with Trypanosoma brucei representing the earliest-diverging lineage, we have now found evidence for the monophyly of trypanosomes. Addition of new taxa which subdivide long branches (such as that of T. brucei) have helped to identify homoplasies responsible for the paraphyletic trees in previous studies. Although the monophyly of the trypanosome clade is supported in the bootstrap analyses for maximum likelihood at 97% and maximum parsimony at 92%, there is only a small difference in ln-likelihood value or tree length between the most optimal monophyletic tree and the best suboptimal paraphyletic tree. Within the trypanosomatid subtree, the clade of trypanosomes is a sister group to the monophyletic clade of the nontrypanosome genera. Different groups of trypanosomes group on the tree according to their mode of transmission. This suggests that the adaptation to invertebrate vectors plays a more important role in the trypanosome evolution than the adaptation to vertebrate hosts. Received: 5 July 1996 / Accepted: 26 September 1996     

Simultaneous Molecular and Morphological Analysis of Braconid Relationships (Insecta: Hymenoptera: Braconidae) Indicates Independent mt-tRNA Gene Inversions Within a Single Wasp Family

We investigated the phylogeny of the Braconidae (Insecta: Hymenoptera) with a much expanded data set compared with that of previous attempts, employing 16S and 28S rDNA gene fragments, together with a suite of morphological characters, from 74 ingroup taxa. Most notably, parsimony analyses under a range of models recovered the Aphidiinae as sister group to the cyclostomes and the Ichneutinae as sister group to the microgastroids. The cyclostomes were recovered as a natural group only if certain, putatively misplaced genera (Mesostoa, Aspilodemon) were excluded from them. Further, mapping of rearrangement characters onto this phylogeny of the Braconidae indicated parallel inversions of the mt-tRNA^D gene, with the two instances of inversion distinguishable by the presence or absence of an additional tRNA gene (tRNA^H). This is the first report of a parallel inversion of a mt-tRNA gene and makes the Braconidae the first metazoan family to display both parallel inversions and translocations. Received: 6 April 2001 / Accepted: 9 July 2001     

Ancient and Recent Horizontal Invasions of Drosophilids by P Elements

P elements of two different subfamilies designated as M- and O-type are thought to have invaded host species in the Drosophila obscura group via horizontal transmission from external sources. Sequence comparisons with P elements isolated from other species suggested that the horizontal invasion by the O-type must have been a rather recent event, whereas the M-type invasion should have occurred in the more distant past. To trace the phylogenetic history of O-type elements, additional taxa were screened for the presence of O- and M-type elements using type-specific PCR primers. The phylogeny deduced from the sequence data of a 927-bp section (14 taxa) indicate that O-type elements have undergone longer periods of regular vertical transmission in the lineages of the saltans and willistoni groups of Drosophila. However, starting from a species of the D. willistoni group they were transmitted horizontally into other lineages. First the lineage of the D. affinis subgroup was infected, and finally, in a more recent wave of horizontal spread, species of three different genera were invaded by O-type elements from the D. affinis lineage: Scaptomyza, Lordiphosa, and the sibling species D. bifasciata/D. imaii of the Drosophila obscura subgroup. The O-type elements isolated from these taxa are almost identical (sequence divergence <1%). In contrast, no such striking similarities are observed among M-type elements. Nevertheless, the sequence phylogeny of M-type elements is also not in accordance with the phylogeny of their host species, suggesting earlier horizontal transfer events. The results imply that P elements cross species barriers more frequently than previously thought but require a particular genomic environment and thus seem to be confined to a rather narrow spectrum of host species. Consequently, different P element types acquired by successive horizontal transmission events often coexist within the same genome. Received: 15 May 2000 / Accepted: 19 July 2000     

Phylogeny of Drosophila and related genera inferred from the nucleotide sequence of the Cu,Zn Sod gene

The phylogeny and taxonomy of the drosophilids have been the subject of extensive investigations. Recently, Grimaldi (1990) has challenged some common conceptions, and several sets of molecular data have provided information not always compatible with other taxonomic knowledge or consistent with each other. We present the coding nucleotide sequence of the Cu,Zn superoxide dismutase gene (Sod) for 15 species, which include the medfly Ceratitis capitata (family Tephritidae), the genera Chymomyza and Zaprionus, and representatives of the subgenera Dorsilopha, Drosophila, Hirtodrosophila, Scaptodrosophila, and Sophophora. Phylogenetic analysis of the Sod sequences indicates that Scaptodrosophila and Chymomyza branched off the main lineage before the major Drosophila radiations. The presence of a second intron in Chymomyza and Scaptodrosophila (as well as in the medfly) confirms the early divergence of these two taxa. This second intron became deleted from the main lineage before the major Drosophila radiations. According to the Sod sequences, Sophophora (including the melanogaster, obscura, saltans, and willistoni species groups) is older than the subgenus Drosophila; a deep branch splits the willistoni and saltans groups from the melanogaster and obscura groups. The genus Zaprionus and the subgenera Dorsilopha and Hirtodrosophila appear as branches of a prolific “bush” that also embraces the numerous species of the subgenus Drosophila. The Sod results corroborate in many, but not all, respects Throckmorton's (King, R.C. (ed) Handbook of Genetics. Plenum Press, New York, pp. 421–469, 1975) phylogeny; are inconsistent in some important ways with Grimaldi's (Bull. Am. Museum Nat. Hist. 197:1–139, 1990) cladistic analysis; and also are inconsistent with some inferences based on mitochondrial DNA data. The Sod results manifest how, in addition to the information derived from nucleotide sequences, structural features (i.e., the deletion of an intron) can help resolve phylogenetic issues. Correspondence requests to: F. J. Ayala     

Molecular Data from the Chloroplast rpoC1 Gene Suggest a Deep and Distinct Dichotomy of Contemporary Spermatophytes into Two Monophyla: Gymnosperms (Including Gnetales) and Angiosperms

Partial sequences of the rpoC1 gene from two species of angiosperms and three species of gymnosperms (8330 base pairs) were determined and compared. The data obtained support the hypothesis that angiosperms and gymnosperms are monophyletic and none of the recent groups of the latter is sister to angiosperms. Received: 20 November 1998 / Accepted: 26 April 1999     

Phylogeny of Drosophila and related genera: conflict between molecular and anatomical analyses

Drosophila species are extensively used in biological research; yet, important phylogenetic relationships within the genus and with related genera remain unresolved. The combined data for three genes (Adh, Sod, and Gpdh) statistically resolves outstanding issues. We define the genus Drosophila inclusively so as to include Scaptomyza and Zaprionus (considered distinct genera in the taxonomy of Wheeler, 1981) but excluding Scaptodrosophila. The genus Drosophila so defined is monophyletic. The subgenus Sophophora (including the melanogaster, obscura, and willistoni groups) is monophyletic and the sister clade to all other Drosophila subgenera. The Hawaiian Drosophila (including Scaptomyza) is a monophyletic group, but the subgenus Drosophila is not monophyletic, because the immigrans group is more closely related to the subgenus Hirtodrosophila than to other species of the subgenus Drosophila, such as the virilis and repleta groups.     

Identification and Characterization of the Cecropin Antibacterial Protein Gene Locus in Drosophila virilis

Cecropin is a type of antibacterial peptide that is synthesized in response to infection and has been characterized in many insect species and one mammal. The Cecropin locus of Drosophila melanogaster also contains the gene Andropin, which has been identified only in this species and encodes a male-specific antibacterial peptide. As a first step in studying the molecular evolution of the cecropin and andropin genes among Drosophila species, we have isolated genomic clones that cover the Cecropin locus in Drosophila virilis. The cloned region totals approximately 25 kb, within which a 9-kb fragment contains four cecropin genes and one pseudogene. All four genes have a high level of sequence homology to D. melanogaster Cecropin, about 80% identity in the coding regions, and the intron positions are conserved. As in D. melanogaster and other insects, κB-related cis-regulatory elements are found upstream of these cecropin genes. An Andropin-related sequence was not identified in D. virilis; however, genome Southern hybridizations suggest that Andropin-related sequences are present in at least the melanogaster species subgroup. Analysis of 19 insect cecropin genes identifies a common ancestral Cecropin before the divergence of Diptera and Lepidoptera. In addition, D. melanogaster and D. virilis can be identified by monophyletic clades for Cecropin. In contrast, the Lepidopteran species show polyphyletic relationships for duplicated cecropin genes. Received: 12 August 1996 / Accepted: 18 October 1996     

Evolution of the Integrin α and β Protein Families

A phylogenetic analysis of vertebrate and invertebrate α integrins supported the hypothesis that two major families of vertebrate α integrins originated prior to the divergence of deuterostomes and protostomes. These two families include, respectively, the αPS1 and αPS2 integrins of Drosophila melanogaster, and each family has duplicated repeatedly in vertebrates but not in Drosophila. In contrast, a third family (including αPS3) has duplicated in Drosophila but is absent from vertebrates. Vertebrate αPS1 and αPS2 family members are found on human chromosomes 2, 12, and 17. Linkage of these family members may have been conserved since prior to the origin of vertebrates, and the two genes duplicated simultaneously. A phylogenetic analysis of β integrins did not clearly resolve whether vertebrate β integrin genes duplicated prior to the origin of vertebrates, although it suggested that at least the gene encoding vertebrate β4 may have done so. In general, the phylogeny of neither α nor β integrins showed a close correspondence with patterns of α–β heterodimer formation or other functional characteristics. One major exception to this trend involved αL, αM, αX, and αD, a monophyletic group of immune cell-expressed α integrins, which share a number of common functional characteristics and have evolved in coordinated fashion with their β integrin partners. Received: 22 June 2000 / Accepted: 11 September 2000     

Molecular phylogenetic analysis of Arenaria (Caryophyllaceae: tribe Arenarieae) and its allies inferred from nuclear DNA internal transcribed spacer and plastid DNA rps16 sequences

The systematics and phylogeny of the genus Arenaria and allied genera are unresolved. The use of morphological data has resulted in contradictory taxonomic concepts in the past due to their homoplastic nature. We present a phylogenetic analysis based on internal transcribed spacer (ITS) and rps16 sequence data of 140 (132 taxa) and 131 (120 taxa) accessions, respectively. Maximum parsimony and Bayesian analyses of each marker produced nearly congruent trees. Monophyly of Arenaria s.s. and Eremogone is confirmed here. Our results corroborate earlier results indicating that Arenaria subgenus Odontostemma is monophyletic, but outside the core group of Arenaria. Arenaria subgenus Solitaria is sister to Odontostemma and also not closely related to the latter; both of these subgenera are excluded from Arenaria and treated as distinct genera. The molecular data indicate that the ‘Arenaria s.s. clade’ consists of a few well‐supported subgroups and that the current subgeneric classification of the genus does not reflect evolutionary history. Arenaria subgenus Leiosperma is clearly monophyletic, but we reduce it to sectional level. Our molecular data show that the monotypic Arenaria subgenera Porphyrantha and Arenariastrum are nested in A. subgenus Arenaria, whereas subgenus Eremogoneastrum is included in Eremogone. None of the species‐rich sections in subgenus Arenaria is monophyletic. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 178 , 648–669.     

Phylogenetic classification of the Drosophilidae Rondani (Diptera): the role of morphology in the postgenomic era

Molecular sequences now overwhelm morphology in phylogenetic inference. Nonetheless, most molecular studies are conducted on a limited number of taxa, as DNA rarely can be analysed from old museum types or fossils. During the last 20 years, more than 150 molecular studies have challenged the current phylogenetic classification of the family Drosophilidae Rondani based on morphological characters. Most studies concerned a single genus, Drosophila Fallén, and included only few representative species from 17 out of the 78 genera of the family. Therefore, these molecular studies were unable to provide an alternative classification scheme. A supermatrix analysis of seven nuclear and one mitochondrial genes (8248 bp) for 33 genera was conducted using outgroups from one calyptrate and four ephydroid families. The Bayesian phylogeny was consistent with previous molecular studies including whole genome sequences and divided the Drosophilidae into four monophyletic clades. Morphological characters, mostly male genitalia, then were compared thoroughly between the four clades and homologous character states were identified. These states were then checked for 70 genera and a revised phylogenetic, family‐group classification for the Drosophilidae is proposed. Two genera –Cladochaeta Coquillett and Diathoneura Duda – of the tribe Cladochaetini Grimaldi are transferred to the family Ephydridae. The Drosophilidae is divided into two subfamilies: Steganinae Hendel (30 genera) and Drosophilinae Rondani (43 genera). A further two genera, Apacrochaeta Duda and Sphyrnoceps de Meijere, are incertae sedis, and Palmophila Grimaldi, is synonymized with Drosophila syn.n. The Drosophilinae is subdivided into two tribes: the re‐elevated Colocasiomyini Okada (nine genera) and Drosophilini Okada. The paraphyly of the genus Drosophila was not resolved to avoid affecting the binomina of important laboratory model species; however, its subgeneric classification was revised in light of molecular and morphological data. Three subgenera, namely Chusqueophila Brncic, Phloridosa Sturtevant and Psilodorha Okada, were synonymized with the subgenus Drosophila (Drosophila) Fallén syns.n. Among the 45 species groups and 5 species complexes of Drosophila (Drosophila), 22 groups and 1 complex were transferred to the subgenus Drosophila (Siphlodora) Patterson & Mainland and 6 groups, 2 species subgroups and 3 complexes are considered incertae sedis within the genus Drosophila. Different morphological characters provide different signals at different phylogenetic scales: thoracic characters (wing venation and presternal shape) discriminate families; grasping and erection‐related characters discriminate subfamilies to tribes; whereas phallic paraphyses, i.e. auxiliary intromittent organs, discriminate genera and Drosophila subgenera. The study shows the necessity of analysing morphological characters within a molecular phylogenetic framework to translate molecular phylogenies into taxonomically‐comprehensive classifications.     

Multiple Recurrent Evolution of Trophic Types in Northeastern Atlantic and Mediterranean Seabreams (Sparidae, Percoidei)

Seabreams are among the most valuable fish, not only for small-scale and semiindustrial fisheries but also for aquaculture throughout the Mediterranean. Nevertheless, their phylogenetic relationships are not at all clear. The current taxonomy is based solely on trophic morphology and rests on the assumption that each trophic type evolved only once from a less specialized ancestral condition. We analyzed a 486-bp segment of the mitochondrial 16S rDNA of all 24 seabream species described for the northeastern Atlantic and the Mediterranean to elucidate their generic and subfamily-level relationships. Three major mitochondrial lineages, each comprising species of different feeding strategy and dentition, were found that do not agree with the present taxonomic assignments. Most of the investigated genera were resolved paraphyletically, indicating that the structure and arrangement of oral teeth must have repeatedly evolved from a less specialized ancestral condition. Further, the genus Sparus was resolved as distantly related to the genus Pagrus, in that it was assigned to a different major mitochondrial lineage. Oblada melanura was consistently placed within the Diplodus radiation as sister group to Diplodus puntazzo. Our phylogenetic hypothesis thus suggests multiple independent origins of similar trophic specializations within the Sparidae and indicates that the currently recognized three or four subfamilies need to be redefined. Received: 5 October 1999 / Accepted: 9 November 1999     

Phylogenetic Relationships of Orders Within the Class Colpodea (Phylum Ciliophora) Inferred from Small Subunit rRNA Gene Sequences

Molecular analyses have been used recently to refine our knowledge of phylogenetic relationships within the ciliated protozoa (phylum Ciliophora). A current Hennigian phylogeny of the orders in the class Colpodea, based on light and electron microscopic analyses, makes three important assumptions with regard to apomorphic character states, namely, (1) that the kreyellid silver line evolved early in colpodean phylogeny, separating bryometopids, such as Bryometopus, from all other colpodeans; (2) that the macro–micronuclear complex is an autapomorphy of the cyrtolophosidids, such as Platyophrya; and (3) that merotelokinetal stomatogenesis is an apomorphic character of colpodids, such as Colpoda, Bresslaua, and Pseudoplatyophrya. These predictions of relationships within the class Colpodea were investigated by determining the complete small subunit rRNA gene sequences for the colpodid Bresslaua vorax, the grossglockneriid Pseudoplatyophrya nana, and the cyrtolophosidid Platyophrya vorax and a partial sequence for the bryometopid Bryometopus sphagni. These sequences were combined with the previously published complete SSrRNA sequences for the colpodid Colpoda inflata and the bursariomorphid Bursaria truncatella. The affiliations were assessed using both distance matrix and maximum-parsimony analyses. The tree topologies for the class Colpodea were identical in all analyses, with bootstrap support for bifurcations always exceeding 60%. The results suggest the following. (1) Since the clade including Bryometopus and its sister taxon, Bursaria, is never basal, the kreyellid silver-line system evolved later in colpodean phylogeny and does not separate bryometopids from all other colpodeans. (2) Since Platyophrya is always the sister taxon to the other five genera, there is a fundamental phylogenetic significance for its macro–micronuclear complex. (3) Since the colpodids, Colpoda, Bresslaua, and Pseudoplatyophrya, always group in one clade, merotelokinetal stomatogenesis appears to be a derived character state. Received: 30 June 1998 / Accepted: 3 December 1998     

Towards a phylogeny of the flesh flies (Diptera: Sarcophagidae): morphology and phylogenetic implications of the acrophallus in the subfamily Sarcophaginae

The morphology of the acrophallus, the distal portion of the male phallus carrying the phallotreme, was studied in 72 exemplar species representing 56 genera and subgenera of the flesh fly subfamily Sarcophaginae. For 42 of those species, scanning electron microscopy was used to clarify the phallic morphology. Terms used to describe the male genitalia were updated based on new interpretations of homology. Male genitalic characters, combined with other morphological characters of adult males and females and of larvae, were used to construct a phylogeny. The monophyly of the subfamily was supported, and some generic‐level sister‐group relationships proposed in the literature, but without previous cladistic analyses, were also supported. The genus Blaesoxipha Loew, as currently recognized, was not monophyletic in our analysis. The genus Helicobia Coquillett is synonymized with Sarcophaga Meigen syn. nov. and treated as a subgenus of the latter. The Sarcophaga subgenera Neobellieria Blanchard and Mehria Enderlein were not monophyletic. Many of the clades in the analysis were supported primarily or exclusively by male genitalic character states, highlighting the importance of the male genitalia as a source of morphological characters for sarcophagine phylogeny. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 158 , 740–778.     

Molecular Evolution of P Transposable Elements in the Genus Drosophila. II. The obscura Species Group

A phylogenetic analysis of P transposable elements in the Drosophila obscura species group is described. Multiple P sequences from each of 10 species were obtained using PCR primers that flank a conserved region of exon 2 of the transposase gene. In general, the P element phylogeny is congruent with the species phylogeny, indicating that the dominant mode of transmission has been vertical, from generation to generation. One manifestation of this is the distinction of P elements from the Old World obscura and subobscura subgroups from those of the New World affinis subgroup. However, the overall distribution of elements within the obscura species group is not congruent with the phylogenetic relationships of the species themselves. There are at least four distinct subfamilies of P elements, which differ in sequence from each other by as much as 34%, and some individual species carry sequences belonging to different subfamilies. P sequences from D. bifasciata are particularly interesting. These sequences belong to two subfamilies and both are distinct from all other P elements identified in this survey. Several mechanisms are postulated to be involved in determining phylogenetic relationships among P elements in the obscura group. In addition to vertical transmission, these include retention of ancestral polymorphisms and horizontal transfer by an unknown mating-independent mechanism.