Heterogeneous Clade Research Articles

A primordial Orange Carotenoid Protein: Structure, photoswitching activity and evolutionary aspects

Cyanobacteria are photosynthesizing prokaryotes responsible for the Great Oxygenation Event on Earth ~2.5 Ga years ago. They use a specific photoprotective mechanism based on the 35-kDa photoactive Orange Carotenoid Protein (OCP), a promising target for developing novel optogenetic tools and for biomass engineering. The two-domain OCP presumably stems from domain fusion, yet the primitive thylakoid-less cyanobacteria Gloeobacter encodes a complete OCP. Its photosynthesis regulation lacks the so-called Fluorescence Recovery Protein (FRP), which in Synechocystis inhibits OCP-mediated phycobilisome fluorescence quenching, and Gloeobacter OCP belongs to the recently defined, heterogeneous clade OCPX (GlOCPX), the least characterized compared to OCP2 and especially OCP1 clades. Here, we describe the first crystal structure of OCPX, which explains unique functional adaptations of Gloeobacter OCPX compared to OCP1 from Synechocystis. We show that monomeric GlOCPX exploits a remarkable intramolecular locking mechanism stabilizing its dark-adapted state and exhibits drastically accelerated, less temperature-dependent recovery after photoactivation. While GlOCPX quenches Synechocystis phycobilisomes similar to Synechocystis OCP1, it evades interaction with and regulation by FRP from other species and likely uses alternative mechanisms for fluorescence recovery. This analysis of a primordial OCPX sheds light on its evolution, rationalizing renaming and subdivision of the OCPX clade into subclades – OCP3a, OCP3b, OCP3c.

Detection of Cetacean Poxvirus in Peruvian Common Bottlenose Dolphins (Tursiops truncatus) Using a Pan-Poxvirus PCR.

Cetacean poxviruses (CePVs) cause ‘tattoo’ skin lesions in small and large cetaceans worldwide. Although the disease has been known for decades, genomic data for these poxviruses are very limited, with the exception of CePV-Tursiops aduncus, which was completely sequenced in 2020. Using a newly developed pan-pox real-time PCR system targeting a conserved nucleotide sequence located within the Monkeypox virus D6R gene, we rapidly detected the CePV genome in typical skin lesions collected from two Peruvian common bottlenose dolphins (Tursiops truncatus) by-caught off Peru in 1993. Phylogenetic analyses based on the sequencing of the DNA polymerase and DNA topoisomerase genes showed that the two viruses are very closely related to each other, although the dolphins they infected pertained to different ecotypes. The poxviruses described in this study belong to CePV-1, a heterogeneous clade that infects many species of dolphins (Delphinidae) and porpoises (Phocoenidae). Among this clade, the T. truncatus CePVs from Peru were more related to the viruses infecting Delphinidae than to those detected in Phocoenidae. This is the first time that CePVs were identified in free-ranging odontocetes from the Eastern Pacific, surprisingly in 30-year-old samples. These data further suggest a close and long-standing pathogen–host co-evolution, resulting in different lineages of CePVs.

Phylogenetic relationships amongst the snake-eyed lizards of the genus Ablepharus Fitzinger, 1823 (Sauria, Scincidae) in the Iranian Plateau based on mtDNA sequences

We recovered molecular phylogenetic relationships amongst species of the genusAblepharusin Iran and Iraq. Partial sequences of three mitochondrial genes (cytochrome C oxidase subunit I – COI, 12S rRNA and 16S rRNA) were analysed. In addition, phylogenetic relationships and taxonomic evaluation ofAblepharusspecies in Cyprus, India, Greece, Turkey and Syria were performed using partial sequences of the 16S rRNA gene. Phylogenetic trees and estimated genetic distances showed that theAblepharuspopulations of Iran and Iraq clustered into three distinct clades. One is found in northwest Iran (A. bivittatusin Ardabil, East and West Azerbaijan and Hamedan Provinces). The second clade, formed byA. chernovi, is found only in Uromia. The third and most heterogeneous clade is divided into two subclades, the first includes two lineages ofAblepharusin Khorasan Razavi and Semnan Provinces (A. pannonicus) and in eastern and south-eastern Iran (A. grayanus); the second subclade is distributed in the eastern part of Iraq and west and south-western Iran (Ablepharussp.). Our analyses indicated that splitting ofA. chernoviwithin the genus occurred in the early Miocene [about 22.5 million years ago (Mya)].Ablepharus bivittatusdiverged 15.2 Mya, in the middle Miocene.Ablepharus pannonicusdiverged in the late Miocene (8.4 Mya) andA. grayanusseparated in the late Miocene (6.7 Mya). The lineages of eastern Iraq and south-western Iran (Ablepharussp.) diverged also in the late Miocene (7.0 Mya).

Multidrug-Resistant Hypervirulent Klebsiella pneumoniae Found Persisting Silently in Infant Gut Microbiota.

Since the spread of multidrug-resistant Klebsiella pneumoniae (MDRKP) strains is considered as a challenge for patients with weakened or suppressed immunity, the emergence of isolates carrying determinants of hypervirulent phenotypes in addition may become a serious problem even for healthy individuals. The aim of this study is an investigation of the nonoutbreak K. pneumoniae emergence occurred in early 2017 at a maternity hospital of Kazan, Russia. Ten bacterial isolates demonstrating multiple drug resistance phenotypes were collected from eight healthy full-term breastfed neonates, observed at the maternity hospital of Kazan, Russia. All the infants and their mothers were dismissed without symptoms or complaints, in a satisfactory condition. Whole-genome shotgun (WGS) sequencing was performed with the purpose to track down a possible spread source(s) and obtain detailed information about resistance determinants and pathogenic potential of the collected isolates. Microdilution tests have confirmed production of extended-spectrum β-lactamases (ESBL) and their resistance to aminoglycoside, β-lactam, fluoroquinolone, sulfonamide, nitrofurantoin, trimethoprim, and fosfomycin antibiotics and Klebsiella phage. The WGS analysis has revealed the genes that are resistant to aminoglycosides, fluoroquinolones, macrolides, sulfonamides, chloramphenicols, tetracyclines, and trimethoprim and ESBL determinants. The pangenome analysis had split the isolates into two phylogenetic clades. The first group, a more heterogeneous clade, was represented by 5 isolates with 4 different in silico multilocus sequence types (MLSTs). The second group contained 5 isolates from infants born vaginally with the single MLST ST23, positive for genes corresponding to hypervirulent phenotypes: yersiniabactin, aerobactin, salmochelin, colibactin, hypermucoid determinants, and specific alleles of K- and O-antigens. The source of the MDRKP spread was not defined. Infected infants have shown no developed disease symptoms.

Morphological and molecular characterisation of Moshajia idiofora Siddiqi, 1982 (Dorylaimida: Qudsianematidae), with new insights into the phylogeny of the enigmatic Lordellonematinae

Summary Seven populations of Moshajia idiofora, six from India and one from Japan, are characterised, including morphological description, morphometrics, LM and SEM observations, and molecular (18S rDNA gene sequence) analysis. These populations are compared to previous records of the species as well as its closest species. Two of these species, M. cultristyla and M. qasimi, are regarded as junior synonyms of M. idiofora. SEM pictures provide new details of the lip region form. Molecular data indicate that M. idiofora belongs to a morphologically heterogeneous clade whose components share the absence of a distinctly developed pars refringens vaginae and raise a serious doubt about the traditional position of Lordellonematinae representatives in the Dorylaimina system.

More amoebae from the deep-sea: Two new marine species of Vexillifera (Amoebozoa, Dactylopodida) with notes on taxonomy of the genus

Two marine members of the genus Vexillifera Schaeffer, 1926 (Amoebozoa, Dactylopodida) are described. Vexillifera abyssalis n. sp. originates from an abyssal sample of the Western Atlantic 4.5 km deep, which is the first unambiguous record of a deep-sea Vexillifera. The second species, V. kereti n. sp. was isolated from the soft bottom sediments of the White Sea (depth 106 m). An analysis of available data on the genus Vexillifera shows that it comprises many different species, yet they are very unevenly studied. The majority of species have only been described using light microscopy, and their phylogenetic relationships with other amoebae are unclear. However, available small-subunit (SSU) rRNA gene sequences of Vexillifera spp. form a robust, yet very heterogeneous clade in the phylogenetic tree. These species demonstrate a wide range of morphological and ultrastructural characters and originate from diverse habitats, suggesting that Vexillifera may need to be subdivided into several genera in the future. In addition to the described species, we sequenced the COI gene of original CCAP strains of Vexillifera bacillipedes, V. minutissima and Pseudoparamoeba pagei, thereby performing a phylogenetic reconstruction of the Dactylopodida based on a decent taxonomic sampling.

Composition and Genetic Diversity of Mosquitoes (Diptera: Culicidae) on Islands and Mainland Shores of Kenya's Lakes Victoria and Baringo.

The Lake Baringo and Lake Victoria regions of Kenya are associated with high seroprevalence of mosquito-transmitted arboviruses. However, molecular identification of potential mosquito vector species, including morphologically identified ones, remains scarce. To estimate the diversity, abundance, and distribution of mosquito vectors on the mainland shores and adjacent inhabited islands in these regions, we collected and morphologically identified adult and immature mosquitoes and obtained the corresponding sequence variation at cytochrome c oxidase 1 (COI) and internal transcribed spacer region 2 (ITS2) gene regions. A total of 63 species (including five subspecies) were collected from both study areas, 47 of which have previously been implicated as disease vectors. Fourteen species were found only on island sites, which are rarely included in mosquito diversity surveys. We collected more mosquitoes, yet with lower species composition, at Lake Baringo (40,229 mosquitoes, 32 species) than at Lake Victoria (22,393 mosquitoes, 54 species). Phylogenetic analysis of COI gene sequences revealed Culex perexiguus and Cx. tenagius that could not be distinguished morphologically. Most Culex species clustered into a heterogeneous clade with closely related sequences, while Culex pipiens clustered into two distinct COI and ITS2 clades. These data suggest limitations in current morphological identification keys. This is the first DNA barcode report of Kenyan mosquitoes. To improve mosquito species identification, morphological identifications should be supported by their molecular data, while diversity surveys should target both adults and immatures. The diversity of native mosquito disease vectors identified in this study impacts disease transmission risks to humans and livestock.

Fairway patch - a serious emerging disease of couch (syn. bermudagrass) [Cynodon dactylon] and kikuyu (Pennisetum clandestinum) turf in Australia caused by Phialocephala bamuru P.T.W. Wong & C. Dong sp. nov.

Since 2005, a serious emerging disease called fairway patch has occurred on the fairways, tees and green surrounds of a number of golf courses in New South Wales, Queensland, Victoria and Western Australia. It occurs most commonly on couch or bermudagrass (Cynodon dactylon) but has also been found on kikuyu (Pennisetum clandestinum) fairways at one golf course in Sydney. The disease begins as small patches (5–10 cm diam.) of yellow to tan-coloured grass. The patches enlarge into tan-coloured rings up to 1 m in diameter, which often coalesce to form unsightly brown networks of dead and dying grass. The patches are present all the year round but are most pronounced from late spring to late autumn. Fungal isolation from diseased roots and pathogenicity tests have proven that a slow-growing (ca. 2 mm/day on PDA at 25 °C), dark, septate, non-sporulating fungus is the cause of fairway patch. Phylogenetic analysis of the pathogen’s rDNA ITS and partial 28S sequences has shown that it is a new taxon and is described as Phialocephala bamuru P.T.W. Wong & C. Dong sp. nov. It belongs to a heterogeneous clade that includes Phialocephala, Acephala, Vibrissea, Phaeomollisia and Mollisia spp., but, as it is phylogenetically closest to Phialocephala spp. (94–95 % ITS affinities), it has been described as a Phialocephala species although it has not been shown to produce spores in culture. Research is continuing to study the biology and ecology of this ectotrophic root-infecting fungal pathogen and develop practical strategies to manage the disease.

The phylogeny of Anophelinae revisited: inferences about the origin and classification of Anopheles (Diptera: Culicidae)

The evolution of anopheline mosquitoes (Culicidae: Anophelinae) has been the subject of speculation and study for decades, but a comprehensive phylogeny of these insects is far from complete. The results of phylogenetic studies based on morphological and molecular data sets are conspicuously ambiguous. Here, we revisit the phylogenetic relationships of anopheline mosquitoes using state‐of‐the‐art software and cladistic methods to analyse the data set of Harbach & Kitching (2005). We present a refined interpretation of relationships based on analyses of a revised data set that includes an additional species. Implied weighting analyses were conducted with TNT with the concavity constant K ranging from 1 to 33. We determined the optimal K value by summing the GC supports for each MPC and selected the tree with the highest support, K = 30, as the preferred cladogram. We then collapsed the branches with GC support < 1 to obtain the ‘best’ topography of relationships. Genus Chagasia is the basalmost taxon of Anophelinae, and genus Anopheles is recovered as monophyletic but only if Anopheles implexus is excluded and genus Bironella is subordinated within it. The Afrotropical An. implexus is recovered as the sister to all other anophelines, and Christya Theobald, stat. nov., is elevated from synonymy with Anopheles Meigen as a subgenus to accommodate it. The other anophelines comprise two large clades. The first includes the reciprocally monophyletic subgenera Kerteszia + Nyssorhynchus; the second consists of subgenus Cellia as the sister to a heterogeneous clade that includes genus Bironella and subgenera Anopheles, Baimaia, Lophopodomyia and Stethomyia of genus Anopheles. The sister relationship of Cellia and the heterogeneous clade is lost when the branches with GC <1 are collapsed. The monophyly and non‐monophyly of the informal subordinate taxa of subgenera Nyssorhynchus, Cellia and Anopheles, and also evolutionary scenarios, are discussed in relation to previous studies.

Characterisation of pseudorabies virus in domestic pigs and wild boars in Croatia.

Serological data imply that pseudorabies (Aujeszky's disease) is present in domestic pigs and wild boars in Croatia. Therefore, this study included testing of brain tissue samples collected from 200 domestic pigs and 105 wild boars originating from seventeen districts of Croatia. The presence of pseudorabies virus (PrV) DNA was confirmed in samples originating from six domestic pigs (3%) and one wild boar (0.95%). Positive samples were sequenced and analysed on the basis of a gC genome fragment. PrV strains have shown to be genetically identical and they are strongly related to some representative strains in the relatively heterogeneous Clade A. The results clearly show that PrV is still circulating among the domestic pig population in Croatia. Furthermore, the presence of pseudorabies virus in wild boars underlines the importance of this species as a PrV reservoir. Continued surveillance is necessary to track the viral spread in order to achieve final eradication of the disease.

Molecular systematics of Woswasia atropurpurea gen. et sp. nov. (Sordariomycetidae), a fungicolous ascomycete with globose ascospores and holoblastic conidiogenesis

The monotypic genus Woswasia is described for wood-inhabiting and mycotrophic fungi classified in the Sordariomycetidae. It is characterized by unicellular, hyaline, globose to ellipsoid, verruculose ascospores; unitunicate long-stipitate asci with an apical annulus staining blue in aqueous cotton blue and perithecia with a long neck immersed in a stroma exhibiting a conspicuous pH-dependent color reaction. In vitro, it produces branched subhyaline to hyaline conidiophores with terminally arranged sympodial conidiogenous cells and holoblastic hyaline conidia. The remarkable morphological similarity of Woswasia to Amplistroma of the Amplistromataceae, although suggestive of a close relationship, was not confirmed by molecular data. Phylogenetic analysis based on two functional ribosomal genes (large and small subunits of the nuclear rDNA) and one protein-coding gene (second largest subunit of RNA polymerase II) supports the placement of Woswasia in the Sordariomycetidae incertae sedis. Woswasia atropurpurea, the type and only species of the genus, groups within a large heterogeneous clade containing other small or monotypic genera of wood-inhabiting saprobic fungi, which are distantly related and of which the majority lacks an ordinal or familial affiliation. Within the clade a relationship of Woswasia to the freshwater genus Cyanoannulus is suggested.

Macro and Micro Diversity of Clostridium difficile Isolates from Diverse Sources and Geographical Locations

Clostridium difficile has emerged rapidly as the leading cause of antibiotic-associated diarrheal disease, with the temporal and geographical appearance of dominant PCR ribotypes such as 017, 027 and 078. Despite this continued threat, we have a poor understanding of how or why particular variants emerge and the sources of strains that dominate different human populations. We have undertaken a breadth genotyping study using multilocus sequence typing (MLST) analysis of 385 C. difficile strains from diverse sources by host (human, animal and food), geographical locations (North America, Europe and Australia) and PCR ribotypes. Results identified 18 novel sequence types (STs) and 3 new allele sequences and confirmed the presence of five distinct clonal lineages generally associated with outbreaks of C. difficile infection in humans. Strains of animal and food origin were found of both ST-1 and ST-11 that are frequently associated with human disease. An in depth MLST analysis of the evolutionary distant ST-11/PCR ribotype 078 clonal lineage revealed that ST-11 can be found in alternative but closely related PCR ribotypes and PCR ribotype 078 alleles contain mutations generating novel STs. PCR ribotype 027 and 017 lineages may consist of two divergent subclades. Furthermore evidence of microdiversity was present within the heterogeneous clade 1. This study helps to define the evolutionary origin of dominant C. difficile lineages and demonstrates that C. difficile is continuing to evolve in concert with human activity.

Amplified fragment length polymorphism of clinical and environmental Vibrio cholerae from a freshwater environment in a cholera-endemic area, India

BackgroundThe region around Chandigarh in India has witnessed a resurgence of cholera. However, isolation of V. cholerae O1 from the environment is infrequent. Therefore, to study whether environmental nonO1-nonO139 isolates, which are native to the aquatic ecosystem, act as precursors for pathogenic O1 strains, their virulence potential and evolutionary relatedness was checked.MethodsV. cholerae was isolated from clinical cases of cholera and from water and plankton samples collected from freshwater bodies and cholera-affected areas. PCR analysis for the ctxA, ctxB, tcpA, toxT and toxR genes and AFLP with six primer combinations was performed on 52 isolates (13 clinical, 34 environmental and 5 reference strains).ResultsAll clinical and 3 environmental isolates belonged to serogroup O1 and remaining 31 environmental V. cholerae were nonO1-nonO139. Serogroup O1 isolates were ctxA, tcpA (ElTor), ctxB (Classical), toxR and toxT positive. NonO1-nonO139 isolates possessed toxR, but lacked ctxA and ctxB; only one isolate was positive for toxT and tcpA. Using AFLP, 2.08% of the V. cholerae genome was interrogated. Dendrogram analysis showed one large heterogeneous clade (n = 41), with two compact and distinct subclades (1a and 1b), and six small mono-phyletic groups. Although V. cholerae O1 isolates formed a distinct compact subclade, they were not clonal. A clinical O1 strain clustered with the nonO1-nonO139 isolates; one strain exhibited 70% similarity to the Classical control strain, and all O1 strains possessed an ElTor variant-specific fragment identified with primer ECMT. Few nonO1-nonO139 isolates from widely separated geographical locations intermingled together. Three environmental O1 isolates exhibited similar profiles to clinical O1 isolates.ConclusionIn a unique study from freshwater environs of a cholera-endemic area in India over a narrow time frame, environmental V. cholerae population was found to be highly heterogeneous, diverse and devoid of major virulence genes. O1 and nonO1-nonO139 isolates showed distinct lineages. Clinical isolates were not clonal but were closely related, indicating accumulation of genetic differences over a short time span. Though, environment plays an important role in the spread of cholera, the possibility of an origin of pathogenic O1 strains from environmental nonO1-nonO139 strains seems to be remote in our region.

Generic Circumscription in Menyanthaceae: A Phylogenetic Evaluation

Menyanthaceae consist of five genera of aquatic and wetland plants distributed worldwide. The three monotypic genera (Liparophyllum, Menyanthes, and Nephrophyllidium) are clearly differentiated morphologically, but the two larger genera (Nymphoides and Villarsia) contain several taxa of uncertain affinity. We undertook a phylogenetic analysis, using a combination of morphological and molecular data, to resolve relationships among species and to evaluate the current circumscription of genera. DNA sequence data for nuclear (ITS) and chloroplast (rbcL and trnK/matK) gene regions were largely congruent (by partition-homogeneity test), and a combined data phylogeny revealed several strongly supported relationships. Analyses using asterid outgroup taxa supported the monophyly of Menyanthaceae. Menyanthes trifoliata and Nephrophyllidium crista-galli comprised a clade sister to the remainder of the family. Species of Nymphoides, except N. exigua, resolved to a single, deeply-nested clade, indicating that the floating-leaved habit is derived evolutionarily within the family. The genus Villarsia comprised a paraphyletic grade toward Nymphoides, wherein the species resolved to three assemblages: (1) a shallowly nested clade containing V. albiflora, V. calthifolia, V. marchantii, V. parnassifolia, V. reniformis, and V. umbricola; (2) an isolated South African clade including V. manningiana and the type species, V. capensis; and (3) a heterogeneous clade of taxa from three genera, including V. exaltata, V. lasiosperma, and V. latifolia, plus the anomalous species V. capitata, V. congestiflora, Liparophyllum gunnii, and Nymphoides exigua. Our results indicate that the genera Menyanthes, Nephrophyllidium, and Nymphoides should be retained as circumscribed, with the exception that Nymphoides exigua should be restored to Villarsia. The genus Villarsia, however, eventually should be subdivided among monophyletic lineages, whereby in the strict sense Villarsia would contain only South African taxa.

A Molecular Phylogenetic Investigation of Opisthonecta and Related Genera (Ciliophora, Peritrichia, Sessilida)

The gene encoding 18S small subunit ribosomal RNA (ssu rRNA) was sequenced in the sessiline peritrichs Opisthonecta minima and Opisthonecta matiensis, whose free-swimming, paedomorphic trophonts resemble telotrochs. Using these new sequences, phylogenetic trees were constructed with four different methods to test a previously published association between Opisthonecta henneguyi and members of the families Vorticellidae and Astylozoidae. All trees had similar topologies, with O. minima, O. henneguyi, Vorticella microstoma, and Astylozoon enriquesi forming a well-supported, certainly monophyletic clade. On the basis of genetic evidence, genera of the families Opisthonectidae and Astylozoidae are assigned to the family Vorticellidae, which already includes some species with free-swimming morphotypes. The ssu rRNA sequence of O. matiensis places it in the family Epistylididae; its taxonomic revision will be left to another group of authors. A close association of Ophrydium versatile with members of the family Vorticellidae was confirmed, casting doubt on the validity of the family Ophrydiidae. Epistylis galea, Campanella umbellaria, and Opercularia microdiscum are confirmed as comprising an extremely distinct, monophyletic, but morphologically heterogeneous clade that is basal to other clades of sessiline peritrichs.

Population structure and evolution of the Bacillus cereus group.

Representative strains of the Bacillus cereus group of bacteria, including Bacillus anthracis (11 isolates), B. cereus (38 isolates), Bacillus mycoides (1 isolate), Bacillus thuringiensis (53 isolates from 17 serovars), and Bacillus weihenstephanensis (2 isolates) were assigned to 59 sequence types (STs) derived from the nucleotide sequences of seven alleles, glpF, gmk, ilvD, pta, pur, pycA, and tpi. Comparisons of the maximum likelihood (ML) tree of the concatenated sequences with individual gene trees showed more congruence than expected by chance, indicating a generally clonal structure to the population. The STs followed two major lines of descent. Clade 1 comprised B. anthracis strains, numerous B. cereus strains, and rare B. thuringiensis strains, while clade 2 included the majority of the B. thuringiensis strains together with some B. cereus strains. Other species were allocated to a third, heterogeneous clade. The ML trees and split decomposition analysis were used to assign STs to eight lineages within clades 1 and 2. These lineages were defined by bootstrap analysis and by a preponderance of fixed differences over shared polymorphisms among the STs. Lineages were named with reference to existing designations: Anthracis, Cereus I, Cereus II, Cereus III, Kurstaki, Sotto, Thuringiensis, and Tolworthi. Strains from some B. thuringiensis serovars were wholly or largely assigned to a single ST, for example, serovar aizawai isolates were assigned to ST-15, serovar kenyae isolates were assigned to ST-13, and serovar tolworthi isolates were assigned to ST-23, while other serovars, such as serovar canadensis, were genetically heterogeneous. We suggest a revision of the nomenclature in which the lineage and clone are recognized through name and ST designations in accordance with the clonal structure of the population.

Molecular Insights into the Phylogeny of Mormyriform Fishes and the Evolution of Their Electric Organs; pp. 330–335

In this report we generate a partial phylogeny of the mormyriform fishes using mitochondrial DNA sequences from twelve species of mormyriforms belonging to five genera. Electric organs and electric organ discharges are also examined. We have sequenced and aligned 373 bases from the mitochondrial 12S rRNA and 559 bases from the 16s rRNA from fourteen species of the superorder Osteoglossomorpha. Two non-mormyriform genera were used as outgroups. Three phylogenetic methods generated concordant partial phylogenies for these fish. Our analysis focuses on the genus Brienomyrus, which is a heterogeneous clade with at least eleven nominal species. Six morphs from Gabon had distinctive EODs but were morphologically 'cryptic' in that they all had the brachyistius-like body morphology. DNA analysis fully supports the EOD data that the six morphs represent distinct clades. The group from Gabon is monophyletic, while B.brachyistius from West Africa is a separate lineage. B. niger, a second distinct lineage, is a sister group to the six species from Gabon. Petrocephalus is the sister group of all the genera of the subfamily Mormyrinae so far analyzed, thereby confirming previous osteological results. Gymnarchus niloticus is the sister group of the family Mormyridae, also confirming an earlier phylogenetic hypothesis based on morphology. The molecular data adds polarity to electric organ characteristics. Stalkless electrocytes appear to be primitive. Petrocephalus, with non-penetrating stalked electrocytes innervated on the posterior side, represents an ancestral state for the Mormyridae, while Marcusenius, Brienomyrus and Gnathonemus with penetrating-stalked electrocytes, represent the apomorphic condition. Two species with doubly-penetrating electrocytes innervated on the posterior side may represent a transitional stage. At least two species of Brienomyrus appear to have reverted to non-penetrating stalked electrocytes, possibly through paedomorphosis.

Molecular Insights into the Phylogeny of Mormyriform Fishes and the Evolution of Their Electric Organs; pp. 343–351

In this report we generate a partial phylogeny of the mormyriform fishes using mitochondrial DNA sequences from twelve species of mormyriforms belonging to five genera. Electric organs and electric organ discharges are also examined. We have sequenced and aligned 373 bases from the mitochondrial 12S rRNA and 559 bases from the 16s rRNA from fourteen species of the superorder Osteoglossomorpha. Two non-mormyriform genera were used as outgroups. Three phylogenetic methods generated concordant partial phylogenies for these fish. Our analysis focuses on the genus <i>Brienomyrus, </i>which is a heterogeneous clade with at least eleven nominal species. Six morphs from Gabon had distinctive EODs but were morphologically 'cryptic' in that they all had the <i>brachyistius-</i>like body morphology. DNA analysis fully supports the EOD data that the six morphs represent distinct clades. The group from Gabon is monophyletic, while <i>B.brachyistius </i>from West Africa is a separate lineage. <i>B. niger, </i>a second distinct lineage, is a sister group to the six species from Gabon. <i>Petrocephalus </i>is the sister group of all the genera of the subfamily Mormyrinae so far analyzed, thereby confirming previous osteological results. <i>Gymnarchus niloticus </i>is the sister group of the family Mormyridae, also confirming an earlier phylogenetic hypothesis based on morphology. The molecular data adds polarity to electric organ characteristics. Stalkless electrocytes appear to be primitive. <i>Petrocephalus, </i>with non-penetrating stalked electrocytes innervated on the posterior side, represents an ancestral state for the Mormyridae, while <i>Marcusenius, Brienomyrus </i>and <i>Gnathonemus </i>with penetrating-stalked electrocytes, represent the apomorphic condition. Two species with doubly-penetrating electrocytes innervated on the posterior side may represent a transitional stage. At least two species of <i>Brienomyrus </i>appear to have reverted to non-penetrating stalked electrocytes, possibly through paedomorphosis.

Molecular insights into the phylogeny of mormyriform fishes and the evolution of their electric organs.

In this report we generate a partial phylogeny of the mormyriform fishes using mitochondrial DNA sequences from twelve species of mormyriforms belonging to five genera. Electric organs and electric organ discharges are also examined. We have sequenced and aligned 373 bases from the mitochondrial 12S rRNA and 559 bases from the 16s rRNA from fourteen species of the superorder Osteoglossomorpha. Two non-mormyriform genera were used as outgroups. Three phylogenetic methods generated concordant partial phylogenies for these fish. Our analysis focuses on the genus Brienomyrus, which is a heterogeneous clade with at least eleven nominal species. Six morphs from Gabon had distinctive EODs but were morphologically 'cryptic' in that they all had the brachyistius-like body morphology. DNA analysis fully supports the EOD data that the six morphs represent distinct clades. The group from Gabon is monophyletic, while B. brachyistius from West Africa is a separate lineage. B. niger, a second distinct lineage, is a sister group to the six species from Gabon. Petrocephalus is the sister group of all the genera of the subfamily Mormyrinae so far analyzed, thereby confirming previous osteological results. Gymnarchus niloticus is the sister group of the family Mormyridae, also confirming an earlier phylogenetic hypothesis based on morphology. The molecular data adds polarity to electric organ characteristics. Stalkless electrocytes appear to be primitive. Petrocephalus, with non-penetrating stalked electrocytes innervated on the posterior side, represents an ancestral state for the Mormyridae, while Marcusenius. Brienomyrus and Gnathonemus with penetrating-stalked electrocytes, represent the apomorphic condition. Two species with doubly-penetrating electrocytes innervated on the posterior side may represent a transitional stage. At least two species of Brienomyrus appear to have reverted to non-penetrating stalked electrocytes, possibly through paedomorphosis.

Molecular Insights into the Phylogeny of Mormyriform Fishes and the Evolution of Their Electric Organs; pp. 336–342

In this report we generate a partial phylogeny of the mormyriform fishes using mitochondrial DNA sequences from twelve species of mormyriforms belonging to five genera. Electric organs and electric organ discharges are also examined. We have sequenced and aligned 373 bases from the mitochondrial 12S rRNA and 559 bases from the 16s rRNA from fourteen species of the superorder Osteoglossomorpha. Two non-mormyriform genera were used as outgroups. Three phylogenetic methods generated concordant partial phylogenies for these fish. Our analysis focuses on the genus Brienomyrus, which is a heterogeneous clade with at least eleven nominal species. Six morphs from Gabon had distinctive EODs but were morphologically 'cryptic' in that they all had the brachyistius-like body morphology. DNA analysis fully supports the EOD data that the six morphs represent distinct clades. The group from Gabon is monophyletic, while B.brachyistius from West Africa is a separate lineage. B. niger, a second distinct lineage, is a sister group to the six species from Gabon. Petrocephalus is the sister group of all the genera of the subfamily Mormyrinae so far analyzed, thereby confirming previous osteological results. Gymnarchus niloticus is the sister group of the family Mormyridae, also confirming an earlier phylogenetic hypothesis based on morphology. The molecular data adds polarity to electric organ characteristics. Stalkless electrocytes appear to be primitive. Petrocephalus, with non-penetrating stalked electrocytes innervated on the posterior side, represents an ancestral state for the Mormyridae, while Marcusenius, Brienomyrus and Gnathonemus with penetrating-stalked electrocytes, represent the apomorphic condition. Two species with doubly-penetrating electrocytes innervated on the posterior side may represent a transitional stage. At least two species of Brienomyrus appear to have reverted to non-penetrating stalked electrocytes, possibly through paedomorphosis.