Molecular phylogeny of the subgenus Holothuria (Selenkothuria) Deichmann, 1958 (Holothuroidea: Aspidochirotida)

The subgenus Selenkothuria comprises 12 species of tropical shallow water sea cucumbers that share morphological features, such as rods in the body wall and tube feet, modified tentacles for suspension feeding, and cryptic colours. The taxonomic status of this taxon has been controversial, but currently it is accepted as a subgenus of the genus Holothuria. Phylogenetic analyses of mitochondrial genes [cytochrome c oxidase subunit 1 (COI), 16S RNA] of ten species of Selenkothuria and related subgenera showed the polyphyly of this subgenus; monophyly was rejected by a likelihood ratio test. A geographical split divides the species of this subgenus into three different groups: one Indo‐West‐Pacific (IWP) group and two American groups. The IWP group is more closely related to Holothuria (Semperothuria) cinerascens and to other subgenera such as Roweothuria, Holothuria, and Vaneyothuria, whereas the two American groups are more closely related to each other and to some species of the subgenus Halodeima. These results suggest multiple parallel originations and diversification of ossicle morphology within the subgenus Selenkothuria. The current scheme of subgenera for the genus Holothuria is not supported, suggesting the need for a new classification. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165 , 109–120.     

中国冠果蝇属一新种和二新记录种及DNA条形码信息(双翅目:果蝇科)

基于形态学和分子遗传学证据,描述了冠果蝇属1新种Stegana(Stegana)helvippecta sp.nov.和2中国新记录种:S.(S.)furta(Linnaeus,1767)和 S.(S.)taba Okada,1971;利用41 条 DNA 条形码信息,分析了18种冠果蝇的遗传距离,并提供了中国产全部1...     

Two new freshwater species of the genus Jesogammarus (Crustacea: Amphipoda: Anisogammaridae) from northern Japan

Two new anisogammarid species belonging to the genus Jesogammarus were obtained from freshwater habitats from northern Japan. They are Jesogammarus (J.) fujinoi sp. nov. and Jesogammarus (J.) shonaiensis sp. nov. The former new species is diagnosed by the pleonites without spine and the telson without distolateral spine. The other new species differs from the congeneric species in having many dorsal spines on pleonites 1-3.     

Molecular phylogeny of the snubnose darters, subgenus Ulocentra (genus Etheostoma, family Percidae)

Snubnose darters comprise one of the largest subgenera of the percid genus Etheostoma. Many species are described based on differences in male breeding coloration. Few morphological synapomorphies have been proposed for the subgenus and their relatives, making it difficult to delineate monophyletic clades. The phylogenetic relationships of the 20 snubnose darter species of the subgenus Ulocentra and 11 members of its proposed sister subgenus Etheostoma were investigated with partial mitochondrial DNA sequences including 1033 bp encompassing the entire mitochondrial control region, the tRNA-Phe gene, and part of the 12S rRNA gene. Two hypotheses on the relationship and monophyly of the two subgenera were evaluated. Both maximum-parsimony and neighbor-joining analyses supported monophyly of the subgenus Ulocentra and resolved some species-level relationships. The banded darter, E. zonale, and its sister taxon, E. lynceum, were not closely related to the snubnose darters and appear to be diverged from the other members of the subgenus Etheostoma, fitting their former distinction as the recognized subgenus Nanostoma. The sister group to Ulocentra appears to be a restricted species assemblage within the subgenus Etheostoma containing E. blennioides, E. rupestre, E. blennius, and the E. thalassinum species group. The placement of the harlequin darter, E. histrio, is problematic, and it may represent a basal member of Ulocentra or of the restricted subgenus Etheostoma. Despite recent estimates of divergence times between nominal Ulocentra taxa, each species exhibits its own unique set of mtDNA haplotypes, providing no direct evidence for current genetic exchange between species. The nominal taxa of snubnose darters thus appear to be evolving independently from each other and therefore constitute valid species under the Phylogenetic Species Concept.     

Molecular and morphological phylogenetic analysis of an insular radiation in Pacific black flies (Simulium)

Ecological adaptation within islands may have figured prominently in the insular radiation of black flies (subgenus Inseliellum) in the Society Islands, French Polynesia. To aid in understanding the sequence of ecological shifts in this group, we have constructed a phylogeny by using morphology, the cytochrome oxidase I (COI) gene, and the small ribosomal subunit (12S) gene. The strong influence of COI on the combined analysis tree was evident from its contribution to the partitioned Bremer support (62%). The net effect of including 12S was to reduce overall tree support. Different character sets resolved different portions of the combined analysis tree, with COI resolving recent lineages, 12S resolving basal relationships, and morphology supporting the monophyly of taxa having smaller larval feeding fans (oviceps group). The Partition Homogeneity and Kashino-Hasegawa tests indicated significant incongruence between morphological and mitochondrial data. The Templeton test revealed that morphology and the combined (COI + 12S) mitochondrial data were incongruent. This conflict stems primarily from disagreement over the monophyly of taxa having much smaller larval feeding fans. Either convergence in a subset of morphological characters, low phylogenetic signal among mitochondrial sequences, or lineage-sorting causing the mitochondrial data to track an incorrect evolutionary history may be responsible for these results.     

Molecular phylogeny and stripe pattern evolution in the cardinalfish genus Apogon

Cardinalfishes of the genus Apogon (Apogonidae) are one of the most speciose (>200 species) and numerically dominant fishes in coral reefs. Although the genus is divided into 10 subgenera, more than 70% of the species are included in the subgenus Ostorhinchus, most having either horizontal or vertical lines on the body. The phylogenetic relationship among 32 species of subgenus Ostorhinchus and 11 species of four other subgenera of Apogon, based on mitochondrially encoded 12S and 16S ribosomal genes and intervening tRNA(Val) gene, were investigated, using two species of the apogonid genus Fowleria as outgroups. The analyses demonstrated that Ostorhinchus (the most speciose subgenus) was polyphyletic, comprising at least three lineages, Ostorhinchus I, II, and III. Ostorhinchus I included two species, A. (O.) amboinensis and A. (O.) sangiensis, being a sister group to subgenus Zoramia. Ostorhinchus II and III included species with horizontal and vertical lines on the body, respectively. The respective monophylies of the latter two groups, together with a molecular clock calibration, indicated that in the evolutionary history of the genus, basic stripe patterns evolved first (more than 20 million years BP), with subsequent pattern diversification and modification.     

Phylogenetic relationships within the aquatic snail genus Tryonia: implications for biogeography of the North American Southwest

We examined the phylogenetic relationships among 23 species of the North American aquatic snail genus Tryonia (Hydrobiidae), 10 additional representatives of the subfamily Cochliopinae, and two outgroups. Maximum parsimony analysis of a 601-base-pair sequence from the mitochondrial COI gene did not support monophyly of the genus nor its subgenus Paupertryonia. A clade composed of the type species of Tryonia and 16 congeners was strongly supported by the COI data and congruent with recently discovered variation in female genitalic morphology. This "true Tryonia" clade included two large western subclades having a sister-group relationship. The phylogenetic structure of one of these subclades is congruent with vicariant events associated with late Neogene history of the lower Colorado River drainage. The other subclade mirrors development of the modern Rio Grande rift and inception of modern topography in the southwestern Great Basin during the late Neogene. Both subclades are represented in the composite Tryonia fauna of the Amargosa River basin, whose assembly is attributed to the complex geological history of the Death Valley region.     

Systematics of the subgenus Oligocephalus (Teleostei: Percidae: Etheostoma) with complete subgeneric sampling of the genus Etheostoma

The genus Etheostoma is the most diverse clade of freshwater fishes in North America. While studies have been performed with complete sampling of a single subgenus, none have included representatives of all remaining subgenera. The subgenus Oligocephalus is the largest, consisting of 25-27 species in four species groups, and its monophyly has never been clearly demonstrated. The monophyly of this subgenus and its constituent groups was tested using parsimony and Bayesian analyses of ND2 (mtDNA) and the first intron of S7 (nDNA) with complete species sampling from Oligocephalus and complete subgeneric sampling from Etheostoma. Although the subgenus Oligocephalus was not recovered as a monophyletic group in any analyses, monophyletic E. whipplei, Southwestern Darter, and E. spectabile (in part) species groups were recovered in all analyses. All analyses agree that E. okaloosae and both subspecies of E. hopkinsi are not closely related to other members of the subgenus Oligocephalus. E. exile is, however, presenting the strongest evidence yet that recognition of the subgenus Boleichthys is unwarranted.     

Molecular phylogenetic analysis of the dragonfly genera Libellula, Ladona, and Plathemis (Odonata: Libellulidae) based on mitochondrial cytochrome oxidase I and 16S rRNA sequence data

Molecular phylogenetic relationships among members of the odonate genus Libellula (Odonata: Anisoptera: Libellulidae) were examined using 735 bp of mitochondrial COI and 416 bp of 16S ribosomal RNA gene sequences. Considerable debate exists over several relationships within Libellula, as well over the status of two putative genera often placed as subgenera within Libellula: Ladona and Plathemis. Parsimony and maximum-likelihood analyses of the separate and combined data sets indicate that Plathemis is basal and monophyletic and that Ladona is the sister clade to the remainder of Libellula sensu stricto (s.s.) (all species within the genus Libellula, excluding Plathemis and Ladona). Moreover, two European taxa, Libellula fulva and L. depressa, were found to occupy a sister group relationship within the Ladona clade. Relationships within Libellula s.s. are less well resolved. However, monophyletic lineages within the genus are largely consistent with morphologically based subgeneric classifications. Although tree topologies from each analysis differed in some details, the differences were in no case statistically significant. The analysis of the combined COI and 16S data yielded trees with overall stronger support than analyses of either gene alone. Several analyses failed to support the monophyly of Libellula sensu lato due to the inclusion of one or more outgroup species. However, statistical comparisons of topologies produced by unconstrained analyses and analyses in which the monophyly of Libellula was constrained indicate that any differences are nonsignificant. Based on morphological data, we therefore reject the paraphyly of Libellula and accept the outgroup status of Orthemis ferruginea and Pachydiplax longipennis.     

基于线粒体COI基因的大蚊属Tipula系统发育及长角大蚊亚属Tipula (Sivatipula)分类地位初步研究(双翅目:大蚊总科)

大蚊属Tipula Linnaeus,1758是大蚊科中种类最多的属,目前其单系性尚未得到全面验证.此外,长角大蚊亚属Tipula (Sivatipula) Alexander,1964因其极长的触角以及独有的精子泵结构,明显不同于大蚊属其他亚属,使其亚属的分类地位存在争议.本研究基于COI序列对19个大蚊属物种及5个其他属物种进行了系统发育分析,并计算了物种间的遗传距离.研究结果表明:(1)邻接树(NJ)和最大似然树(ML)均显示长角大蚊亚属与大蚊属其他亚属未形成单系,大蚊属的单系性没有得到支持;(2)基于遗传距离和系统发育分析并结合形态信息,结果显示长角大蚊亚属独立于大蚊属内其他亚属,应将其提升为属级分类单元.     

Phylogeny of the genus Aphis Linnaeus, 1758 (Homoptera: Aphididae) inferred from mitochondrial DNA sequences

Aphis is the largest aphid genus in the world and contains several of the most injurious aphid pests. It is also the most reluctant aphid genus to any comprehensive taxonomic treatment: while most species are easily classified into "species groups" that form well defined entities, numerous species within these groups are difficult to tell apart morphologically and identification keys remain ambiguous and mostly rely on host plant affiliation. In this paper, we used partial sequences of COI/COII and CytB genes to reconstruct the first phylogeny of Aphis and discuss the present systematics. The monophyly of the subgenus Bursaphis and of the tree major species groups, Black aphid, Black backed aphid and frangulae-like species was recovered by all phylogenetic analyses. However our data suggested that the nominal subgenus was not monophyletic. Relationships between major species groups were often ambiguous but "Black" and "Black backed" species groups appeared as sister clades. The most striking result of this study was that our molecular data met the same limits as the morphological characters used in classifications: mitochondrial DNA did not allow the differentiation of species that are difficult to identify. Further, interspecies relationships within groups of species for which taxonomic treatment is difficult stayed unresolved. This suggests that species delineation in the genus Aphis is often ambiguous and that diversification might have been a rapid process.     

Aphis (Hemiptera: Aphididae) species groups found in the Midwestern United States and their contribution to the phylogenetic knowledge of the genus

A phylogeny of the genus Aphis Linnaeus, 1 758 was built primarily from specimens collected in the Midwest of the United States. A data matrix was constructed with 68 species and 41 morphological characters with respective character states of alate and apterous viviparous females. Dendrogram topologies of analyses performed using UPGMA (Unweighted Pair Group Method with Arithmetic Mean), Maximum Parsimony and Bayesian analysis of Cytochrome Oxidase I, Elongation Factor 1‐α and primary endosymbiont Buchnera aphidicola 16S sequences were not congruent. Bayesian analysis strongly supported most terminal nodes of the phylogenetic trees. The phylogeny was strongly supported by EF1‐α, and analysis of COI and EF1‐α molecular data combined with morphological characters. It was not supported by single analysis of COI or Buchnera aphidicola 16S. Results from the Bayesian phylogeny show 4 main species groups: asclepiadis, fabae, gossypii, and middletonii. Results place Aphis and species of the genera Protaphis Börner, 1952, Toxoptera Koch, 1856 and Xerobion Nevsky, 1928 in a monophyletic clade. Morphological characters support this monophyly as well. The phylogeny shows that the monophyletic clade of the North American middletonii species group belong to the genus Protaphis: P. debilicornis (Gillette & Palmer, 1929 ), comb. nov., P. echinaceae (Lagos and Voegtlin, 2009 ), comb. nov., and P. middletonii (Thomas, 1879 ). The genus Toxoptera should be considered a subgenus of Aphis (stat. nov.). The analysis also indicates that the current genus Iowana Frison, 1954 should be considered a subgenus of Aphis (stat. nov.).     

Phylogeny of the genus Chironomus (Diptera) inferred from DNA sequences of mitochondrial cytochrome b and cytochrome oxidase I

Two mitochondrial genes, Cytochrome b (Cytb) and Cytochrome c oxidase subunit I (COI), have been used as phylogenetic markers in Chironomids. The nucleotide sequences of 685 bp from Cytb and 596 bp from COI have been determined for 36 Chironomus species from the Palearctic, or Holarctic, and Australasia. The concatenated sequence of 1281 bp from both genes was used to investigate the phylogenetic relationships among these species. The nucleotide sequence alignments were used for construction of phylogenetic trees based on maximum-parsimony and neighbor-joining methods. Both techniques produced similar phylogenies. Monophyly of the genus Chironomus is supported by a bootstrap value of 100% at the basal branch. Six clusters of species have been revealed with high bootstrap values supporting both monophyly of each cluster and the validity of the branching order within each cluster. Four species, C. circumdatus, C. nepeanensis, C. dorsalis, and C. crassiforceps, cannot be placed into any cluster. Cytological phylogenies were constructed using the same set of species, except for C. biwaprimus. These trees showed many similarities to that obtained from the mitochondrial (mt) sequence analysis, but also a number of significant differences. When compared with the tree constructed from the sequence of 23 species available for one of the globin genes, globin 2b (gb2b), there was better support for the mt tree than for the cytological trees. An intron, which varies in its occurrence and position in gb2b, was also investigated and the distribution of the introns supports the phylogenetic history of the genus Chironomus obtained with mt data. The differences observed in the cytological trees seem to be attributable more to the retention of the same chromosome banding sequence across several species, rather than convergent evolutionary events. An important question is the determination of the position of the subgenus Camptochironomus in relation to the representatives of the nominal subgenus Chironomus, since it has been suggested that this is a separate genus. The Camptochironomus species are internal to the trees and have arisen more recently than some of the species of the subgenus Chironomus, indicating that they are not sufficiently differentiated to be considered more than a subgenus.     

Phylogeography of the Namib Desert dung beetles Scarabaeus (Pachysoma) MacLeay (Coleoptera: Scarabaeidae)

Aim Namib biogeography in many instances remains reliant on advanced and detailed systematic studies. This study attempts to combine molecular phylogenetic data, geology and palaeo‐climatic data to (i) resolve the relationships of the 13 morphological species of Scarabaeus (Pachysoma) and (ii) relate their evolution to past climatic and geological events. Location South Africa and Namibia. Methods Sequencing of a 1197 bp segment of the mitochondrial cytochrome oxidase I (COI) gene of the 13 species within Scarabaeus (Pachysoma) was undertaken. Analyses performed included Parsimony and Maximum Likelihood as well as imposing a molecular clock. Results The molecular phylogeny showed strong support for 11 of the 13 morphological species. The remaining two species, S. (P.) glentoni and S. (P.) hippocrates, formed a complex and could not be assigned specific status on the basis of the COI gene phylogeny. Strong support for the three species formerly classified within the genus Neopachysoma was consistently obtained. The subgenus appears to have arisen c. 2.9 Ma. Species within the subgenus arose at different times, with the common ancestor to Neopachysoma and the hippocrates complex having evolved 2.65 and 2.4 Ma, respectively. Scarabaeus (P.) denticollis, S. (P.) rotundigenus, S. (P.) rodriguesi and S. (P.) schinzi are some of the youngest species, having diverged between 2 million and 600,000 years ago. Main conclusions Scarabaeus (Pachysoma) is a derived monophyletic clade within the Scarabaeini. The subgenus appears to be young in comparison with the age of the Namib Desert, which dates back to the Miocene (c. 15 Ma). The psammophilous taxa are shown to disperse with their substratum and habitat, barchan dunes. Clear south/north evolutionary gradients can be seen within the species of this subgenus, which are consistent with the unidirectional wind regime. Species with a suite of mostly plesiomorphic characters have a southerly distribution while their derived psammophilous relatives have central to northern Namib distributions. Major rivers such as the Orange, Buffels and Holgat appear to be gene barriers to certain species as well as areas of origin of speciation events.     

Phylogenetic relationships and phylogeography of the Killifish species of the subgenus Chromaphyosemion (Radda, 1971) in West Africa, inferred from mitochondrial DNA sequences

We have analyzed the phylogenetic relationships of 160 specimens from 88 samples representing all defined species of the African Aplocheiloid subgenus Chromaphyosemion in order to examine the monophyly of this group, the species interrelationships, and to reveal trends in chromosomal evolution and formulate hypotheses about their evolutionary history. The data set comprised 1153 total nucleotides from the mitochondrial 12S rRNA, cytochrome oxidase I, and D-loop. The molecular-based topologies were analyzed by maximum parsimony, maximum likelihood, distance method and Bayesian inference support the monophyly of the subgenus Chromaphyosemion. All populations with ambiguous taxonomic status were assigned to an already described species except A. sp. Rio Muni which corresponds to a still undescribed species. Aphyosemion alpha and A. lugens were in basal position in the different trees that indicate a possible origin of the subgenus Chromaphyosemion in the South Cameroon-North Gabon region. Furthermore, the South Cameroon region (between 2 degrees and 3 degrees of North latitude) that accommodates half of the Chromaphyosemion species is considered to have been a refuge zone during the late quaternary dry events that Africa experienced. Phylogenetic relationships among the subgenus also revealed that chromosomal evolution is complex and should be studied at the intraspecific level.     

中国长柄茧蜂属亚长柄茧蜂亚属记述(膜翅目:茧蜂科)

对长柄茧蜂属Ｓｔｒｅｂｌｏｃｅｒａ亚长柄茧蜂亚属Ａｓｉａｓｔｒｅｂｌｏｃｅｒａ Ｂｅｌｏｋｏｂｙｌｓｋｉｊ（膜翅目：茧蜂科）的种类进行了研究。亚长柄茧蜂亚属仅分布于我国和俄罗斯远东地区。以前仅知２种：具角长柄茧蜂Ｓ．（Ａ．）ｃｏｒｎｕｔａＣｈａｏ,１９６４和大峪长柄茧峰Ｓ．（Ａ．）ｄａｙｕｅｎｓｉｓ Ｗａｎｇ,１９８３。本文记述了该亚属的一新种：扁角长柄茧蜂,新种Ｓ．（Ａ．）Ｐｌａｎｉｃｏｒｎｉ     

Systematics of Chimarrita, a new subgenus of Chimarra (Trichoptera: Philopotamidae)

The subgenus Chimarrita of the genus Chimarra is erected to include three described species, formerly placed in the subgenus Chimarra , and fifteen new species, all with distributions in the Greater Antilles or South America. A phylogeny for the species in the subgenus, and characters supporting monophyly of the subgenus Chimarrita , are proposed, as well as evidence for the monophyly of the subgenera Chimarra and Curgia . Keys are provided for the males and known females of the subgenus. Described species transferred to this subgenus are Chimarra simpliciforma Flint, Chimarra rosalesi Flint, and Chimarra maldonadoi Flint. Chimarra simpliciforma is designated the type species for the subgenus. New species in Chimarra ( Chimarrita ) described in this paper include: Chimarra akantha (Brazil), C . camella (Brazil), C . camura (Brazil), C . chela (Venezuela), C . forcipata (Venezuela), C . heligma (Brazil), C . heppneri (Peru), C . kontilos (Brazil), C . majuscula (Brazil), C . merengue (Dominican Republic), C . neblina (Venezuela), C . prolata (Ecuador), C . pusilla (Venezuela), C . tortuosa (Brazil), and C . xingu (Brazil).     

Phylogenetic and biogeographic diversification of Rhus (Anacardiaceae) in the Northern Hemisphere

Sequences of internal transcribed spacers (ITS) of nuclear ribosomal DNA, the chloroplast ndhF gene, and chloroplast trnL-F regions (trnL intron, and trnL [UAA] 3' exon-trnF [GAA] intergenic spacer) were used for phylogenetic analyses of Rhus, a genus disjunctly distributed in Asia, Europe, Hawaii, North America, and Northern Central America. Both ITS and cpDNA data sets support the monophyly of Rhus. The monophyly of subgenus Rhus was suggested by the combined cpDNA and ITS data, and largely supported in the cpDNA data except that Rhus microphylla of subgenus Lobadium was nested within it. The monophyly of subgenus Lobadium was strongly supported in the ITS data, whereas the cpDNA data revealed two main clades within the subgenus, which formed a trichotomy with the clade of subgenus Rhus plus R. microphylla. The ITS and cpDNA trees differ in the positions of Rhus michauxii, R. microphylla, and Rhus rubifolia, and hybridization may have caused this discordance. Fossil evidence indicates that Rhus dates back to the early Eocene. The penalized likelihood method was used to estimate divergence times, with fossils of Rhus subgenus Lobadium, Pistacia and Toxicodendron used for age constraints. Rhus diverged from its closest relative at 49.1+/-2.1 million years ago (Ma), the split of subgenus Lobadium and subgenus Rhus was at 38.1+/-3.0 Ma. Rhus most likely migrated from North America into Asia via the Bering Land Bridge during the Late Eocene (33.8+/-3.1 Ma). Rhus coriaria from southern Europe and western Asia diverged from its relatives in eastern Asia at 24.4+/-3.2 Ma. The Hawaiian Rhus sandwicensis diverged from the Asian Rhus chinensis at 13.5+/-3.0 Ma. Subgenus Lobadium was inferred to be of North American origin. Taxa of subgenus Lobadium then migrated southward to Central America. Furthermore, we herein make the following three nomenclatural combinations: (1) Searsia leptodictya (Diels) T. S. Yi, A. J. Miller and J. Wen, comb. nov., (2) Searsia pyroides (A. Rich.) T. S. Yi, A. J. Miller and J. Wen, comb. nov., and (3) Searsia undulata (Jacq.) T. S. Yi, A. J. Miller and J. Wen, because our analyses support the segregation of Searsia from Rhus.     

Molecular phylogeny and systematic in the genus Brachycaudus (Homoptera: Aphididae): insights from a combined analysis of nuclear and mitochondrial genes

Phylogenetic relationships among members of the Aphid genus Brachycaudus (Homoptera: Aphididae) were inferred from partial sequences of mitochondrial cytochrome B oxidase (CytB), two partial fragments of mitochondrial cytochrome C oxidase subunit I (COI) and the internal transcribed spacer II (ITS2) of ribosomal DNA. Twenty-nine species, with several specimens per species, were included, representing all the historically recognized species-groups and subgenera used in the genus except the monospecific subgenus Mordvilkomemor. Results indicate that the genus Brachycaudus is a well-supported monophyletic group. While our results validate the monophyly of subgenera Thuleaphis , Appelia and Brachycaudus s. str. , they reveal two discrepancies in the classical taxonomy. First, the monotypic subgenus Nevskyaphis does not appear valid. Second, the traditionally defined Acaudus subgenus is not monophyletic. On the other hand, our phylogenetic trees corroborate Andreev's recent definition of Acaudus and Brachycaudina. However, they clearly show that the subgenera Prunaphis , Nevskyaphis and Scrophulaphis as defined by this author do not form monophyletic groups. Our results also highlight a highly supported clade that has not been discussed by previous authors; this clade could form a new subgenus, the subgenus Nevskyaphis . Finally, our study shows that molecular data and morphology meet the same limits in delimiting species groups and species themselves. Species groups in which taxonomic treatment is difficult are polytomous. Furthermore, except for one node clustering Brachycaudus s. str . and Appelia, intersubgeneric relationships remain poorly resolved even when several genes are added to the phylogenetic analysis. These results, together with previous studies in other aphid groups suggest that diversification might have been a rapid process in aphids.     

Phylogenetic relationships of African killifishes in the genera Aphyosemion and Fundulopanchax inferred from mitochondrial DNA sequences

We have analyzed the phylogenetic relationships of 52 species representing all defined species groups (J. J. Scheel, 1990, Atlas of Killifishes of the Old World, 448 pp.) of the African aplocheiloid fish genera Aphyosemion and Fundulopanchax in order to examine their interrelationships and to reveal trends of karyotypic evolution. The data set comprised 785 total nucleotides from the mitochondrial 12S rRNA and cytochrome b genes. The molecular-based topologies analyzed by both maximum parsimony and neighbor-joining support the monophyly of most previously defined species groups within these two killifish genera. The genus Aphyosemion is monophyletic except for the nested position of Fundulopanchax kunzi (batesi group; subgenus Raddaella) within this clade, suggesting that this taxon was improperly assigned to Fundulopanchax. The remaining Fundulopanchax species sampled were supported as being monophyletic in most analyses. Relationships among the species groups in both genera were not as strongly supported, suggesting that further data will be required to resolve these relationships. Additional sampling from the 16S rRNA gene allowed further resolution of relationships within Fundulopanchax, more specifically identifying the nonannual scheeli group as the basal lineage of this otherwise annual genus. Chromosomal evolution within Aphyosemion has been episodic, with the evolution of a reduced n = 9-10 metacentric complement having occurred in multiple, independent lineages. Polarity of chromosomal reductions within the elegans species group appears to support previous hypotheses concerning mechanisms of karyotypic change within the genus Aphyosemion.