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1.
Am J Bot ; : e16381, 2024 Aug 06.
Artículo en Inglés | MEDLINE | ID: mdl-39107933

RESUMEN

PREMISE: Vigna includes economically vital crops and wild species. Molecular systematic studies of Vigna species resulted in generic segregates of many New World (NW) species. However, limited Old World (OW) sampling left questions regarding inter- and intraspecific relationships in Vigna s.s. METHODS: African species, including the putative sister genus Physostigma, were comprehensively sampled within the context of NW relatives. Maximum likelihood and Bayesian inference analyses of the chloroplast matK-trnK and nuclear ribosomal ITS/5.8 S (ITS) DNA regions were undertaken to resolve OW Vigna taxonomic questions. Divergence dates were estimated using BEAST to date key nodes in the phylogeny. RESULTS: Analyses of matK and ITS data supported five clades of Vigna s.s.: subg. Lasiospron, a reduced subg. Vigna, subg. Haydonia, subg. Ceratotropis, an enlarged subg. Plectrotropis, and a clade including V. kirkii and V. stenophylla. Genome size estimates of 601 Mb for V. kirkii are near the overall mean of the genus, whereas V. stenophylla had a larger genome (810 Mb), similar to some Vigna subg. Ceratotropis or Plectrotropis species. CONCLUSIONS: Former subg. Vigna is reduced to yellow- and blue-flowered species and subg. Plectrotropis is enlarged to mostly all white-, pink-, and purple-flowered species. The age of the split between NW and OW Vigna lineages is ~6-7 Myr. Genome size estimates cannot rule out a polyploid or hybrid origin for V. stenophylla, potentially involving extinct lineage ancestors of Vigna subg. Ceratotropis or Plectrotropis, as indicated by network and phylogenetic analyses. Taxonomic revisions are suggested based on these results.

2.
Ann Bot ; 132(6): 1055-1072, 2023 12 05.
Artículo en Inglés | MEDLINE | ID: mdl-37814841

RESUMEN

BACKGROUND: A general view in the study of pollination syndromes is that floral traits usually represent convergent floral adaptations to specific functional pollinator groups. However, the definition of convergence is elusive and contradictory in the literature. Is convergence the independent evolution of either the same trait or similar traits with the same function? A review of the concept of convergence in developmental biology and phylogenetic systematics may shed new light in studies of pollination syndromes. SCOPE: The aims of this article are (1) to explore the notion of convergence and other concepts (analogy, homoplasy and parallelism) within the theory and practice of developmental evolution and phylogenetic systematics; (2) to modify the definitions of syndromes in order to embrace the concepts of analogy and convergence; (3) to revisit the bat pollination syndrome in the context of angiosperm phylogeny, with focus on the showy 'petaloid' organs associated with the syndrome; (4) to revisit the genetic-developmental basis of flower colour; (5) to raise evolutionary hypotheses of floral evolution associated with the bat pollination syndrome; and (6) to highlight some of the current frontiers of research on the origin and evolution of flowers and its impact on pollination syndrome studies in the 21st century. CONCLUSIONS: The inclusion of the concepts of analogy and convergence within the concept of syndromes will constitute a new agenda of inquiry that integrates floral biology, phylogenetic systematics and developmental biology. Phyllostomid and pteropodid bat pollination syndrome traits in eudicots and monocots represent cases of analogous and convergent evolution. Pollination syndromes are a multivariate concept intrinsically related to the understanding of flower organogenesis and evolution. The formulation of hypotheses of pollination syndromes must consider the phylogenetic levels of universality for both plant and animal taxa, flower development, genetics, homology and evolution, and a clear definition of evolutionary concepts, including analogy, convergence, homoplasy and parallelism.


Asunto(s)
Quirópteros , Polinización , Animales , Filogenia , Quirópteros/genética , Fenotipo , Reproducción , Flores/genética
3.
J Helminthol ; 97: e72, 2023 Sep 08.
Artículo en Inglés | MEDLINE | ID: mdl-37681419

RESUMEN

In this study, morphological and molecular features were used to identify a new Steinernema sp. from Chhattisgarh, India. Morphological and molecular features provide evidence for placing the new species into the "bicornutum" clade. The new species is characterized by the following morphological features: infective juveniles with a body length of 587 (494-671) µm; a distance from the anterior end to excretory pore of 46 (43-50) µm; a distance from anterior end to nerve ring of 72 µm (61-85 µm); and E% of 88 (77-97). The first-generation males are characterised by 27 genital papillae and very short spicules, with a length of 61 µm (53-67) µm. The SW% and GS% ratio of S. shori n. sp. are 139 (107-190) and 75 (62-90), respectively. The new species is further characterized by sequences of the internal transcribed spacer and partial 28S regions of the ribosomal DNA. Phylogenetic analyses show that S. shori n. sp. is most closely related to S. abbasi, S. kandii, and S. yirgalemense.


Asunto(s)
Rabdítidos , Animales , Masculino , Filogenia , India , Rabdítidos/genética , ADN Ribosómico/genética , Genitales
4.
J Nematol ; 55(1): 20230029, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37455851

RESUMEN

Three entomopathogenic nematode populations were isolated from agricultural fields in the Anantnag district of Jammu and Kashmir (India). Sequences of multiple gene regions and phenotypic features show that they are conspecific and represent a novel species. Molecular and morphological features provided evidence for placing the new species into the "Kushidai" clade. Within this clade, analysis of sequence data of the internal transcribed spacer (ITS) gene, the D2D3 region of the 28S rRNA gene, the mitochondrial cytochrome oxidase I (mtCOI) gene, and the mitochondrial 12S (mt12S) gene depicted the novel species as a distinctive entity closely related to Steinernema akhursti, S. kushidai, and S. populi. Phylogenetic analyses also show that the new species is a sister species to S. akhursti, and these two species are closely related to S. kushidai and S. populi. Additionally, the new species does not mate or produce fertile progeny with any of the closely related species, reinforcing its uniqueness from a biological species concept standpoint. The new species is further characterized by the third-stage infective juveniles with almost straight bodies (0.7-0.8 mm length), poorly developed stoma and pharynx, and conoid-elongate tail (49-66 µm) with hyaline posterior part. Adult females are characterized by short and conoid tails bearing a short mucron in the first generation and long conoid tails with thin mucron in the second generation. Adult males have ventrally curved spicules in both generations. Moreover, the first-generation male has rounded manubrium, fusiform gubernaculum, conoid and slightly ventrally curved tails with minute mucron, and the second generation has rhomboid manubrium anteriorly ventrad bent, and tails with long and robust mucron. The morphological, morphometrical, molecular, and phylogenetic analyses support the new species status of this nematode, which is hereby described as Steinernema anantnagense n. sp. The bacterial symbiont associated with S. anantnagense n. sp. represents a novel species, closely related to Xenorhabdus japonica. These findings shed light on the diversity of entomopathogenic nematodes and their symbiotic bacteria, providing valuable information for future studies in this field.

5.
J Helminthol ; 96: e57, 2022 Jul 28.
Artículo en Inglés | MEDLINE | ID: mdl-35900158

RESUMEN

Steinernema populi n. sp. was recovered by baiting from beneath poplar trees in China. Morphological and molecular features provided evidence for placing the new species into the Kushidai clade. The new species is characterized by the following morphological features: third-stage infective juveniles (IJ) with a body length of 1095 (973-1172) µm, a distance from the anterior end to excretory pore of 77 (70-86) µm and a tail length of 64 (55-72) µm. The Body length/Tail length (c) ratio and Anterior end to Excretory pore/ Tail length × 100 (E%) of S. populi n. sp. are substantially greater than those of all other 'Feltiae-Kushidai-Monticolum' group members. The first-generation males can be recognized by a spicule length of 66 (57-77) µm and a gubernaculum length of 46 (38-60) µm. The new species is further characterized by sequences of the internal transcribed spacer and partial 28S regions of the ribosomal DNA. Phylogenetic analyses show that Steinernema akhursti and Steinernema kushidai are the closest relatives to S. populi n. sp.


Asunto(s)
Rabdítidos , Animales , China , ADN Ribosómico/genética , Masculino , Filogenia
6.
J Phycol ; 53(1): 32-43, 2017 02.
Artículo en Inglés | MEDLINE | ID: mdl-27690326

RESUMEN

Next generation sequence data were generated and used to assemble the complete plastomes of the holotype of Membranoptera weeksiae, the neotype (designated here) of M. tenuis, and a specimen examined by Kylin in making the new combination M. platyphylla. The three plastomes were similar in gene content and length and showed high gene synteny to Calliarthron, Grateloupia, Sporolithon, and Vertebrata. Sequence variation in the plastome coding regions were 0.89% between M. weeksiae and M. tenuis, 5.14% between M. weeksiae and M. platyphylla, and 5.18% between M. tenuis and M. platyphylla. We were unable to decipher the complete mitogenomes of the three species due to low coverage and structural problems; however, we assembled and analyzed, the cytochrome oxidase I, II, and III loci and found that M. weeksiae and M. tenuis differed in sequence by 1.3%, M. weeksiae and M. platyphylla by 8.4%, and M. tenuis and M. platyphylla by 8.1%. Evaluation of standard marker genes indicated that sequences from the rbcL, RuBisCO spacer, and CO1 genes closely approximated the pair-wise genetic distances observed between the plastomes of the three species of Membranoptera. A phylogenetic tree based on rbcL sequences showed that M. tenuis and M. weeksiae were sister taxa. Short rbcL sequences were obtained from type specimens of M. dimorpha, M. multiramosa, and M. edentata and confirmed their conspecificity with M. platyphylla. The data support the recognition of three species of Membranoptera occurring south of Alaska: M. platyphylla, M. tenuis, and M. weeksiae.


Asunto(s)
Proteínas Algáceas/genética , Genoma de Planta , Genoma de Plastidios , Rhodophyta/genética , Secuencia de Bases , América del Norte , Océano Pacífico , Filogenia , Rhodophyta/clasificación , Ribulosa-Bifosfato Carboxilasa/genética , Alineación de Secuencia , Especificidad de la Especie
7.
Am J Bot ; 101(12): 2097-112, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25480707

RESUMEN

UNLABELLED: • PREMISE OF THE STUDY: The species-rich Neotropical genera Centropogon, Burmeistera, and Siphocampylus represent more than half of the ∼1200 species in the subfamily Lobelioideae (Campanulaceae). They exhibit remarkable morphological variation in floral morphology and habit. Limited taxon sampling and phylogenetic resolution, however, obscures our understanding of relationships between and within these genera and underscores our uncertainty of the systematic value of fruit type as a major diagnostic character.• METHODS: We inferred a phylogeny from five plastid DNA regions (rpl32-trnL, ndhF-rpl32, rps16-trnK, trnG-trnG-trns, rbcL) using maximum-likelihood and Bayesian inference. Ancestral character reconstructions were applied to infer patterns of fruit evolution.• KEY RESULTS: Our results demonstrate that the majority of species in the genera Centropogon, Burmeistera, and Siphocampylus together form a primarily mainland Neotropical clade, collectively termed the "centropogonids." Caribbean Siphocampylus, however, group with other Caribbean lobelioid species. We find high support for the monophyly of Burmeistera and the polyphyly of Centropogon and mainland Siphocampylus. The ancestral fruit type of the centropogonids is a capsule; berries have evolved independently multiple times.• CONCLUSIONS: Our plastid phylogeny greatly improves the phylogenetic resolution within Neotropical Lobelioideae and highlights the need for taxonomic revisions in the subfamily. Inference of ancestral character states identifies a dynamic pattern of fruit evolution within the centropogonids, emphasizing the difficulty of diagnosing broad taxonomic groups on the basis of fruit type. Finally, we identify that the centropogonids, Lysipomia, and Lobelia section Tupa form a Pan-Andean radiation with broad habitat diversity. This clade is a prime candidate for investigations of Neotropical biogeography and morphological evolution.


Asunto(s)
Evolución Biológica , Campanulaceae/genética , ADN de Plantas/análisis , Frutas/anatomía & histología , Filogenia , Teorema de Bayes , Campanulaceae/anatomía & histología , Campanulaceae/clasificación , Región del Caribe , Clasificación , Ecosistema , Evolución Molecular , Plastidios , Análisis de Secuencia de ADN , Especificidad de la Especie
8.
Zookeys ; 1158: 27-48, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37215692

RESUMEN

A new salamander species of the genus Bolitoglossa is here described from the cloud forests of the western slopes of the Cordillera Oriental of Colombia, in the Cundinamarca department. The most salient characters of this new species are its numerous maxillary and vomerine teeth, its moderate webbing on hands and feet, its short and robust tail, and its chromatic variation. Based on molecular analyses this new species is assigned to the adspersa species group and its status established as the sister species of B.adspersa, with which it was previously confused. Lastly, the distribution, natural history, and conservation status of the new species are discussed.


ResumenDescribimos una nueva especie de salamandra del género Bolitoglossa proveniente de los bosques nublados de la vertiente occidental de la Cordillera Oriental de Colombia, en el departamento de Cundinamarca. Los caracteres más sobresalientes de esta nueva especie son sus numerosos dientes maxilares y vomerinos, su palmeadura moderada en pies y manos, su cola corta pero robusta, y su variación cromática. Basados en análisis moleculares asignamos esta nueva especie al grupo de especies adspersa y establecemos su estatus como especie hermana de B.adspersa, con la cual era previamente confundida. Finalmente, discutimos algunos aspectos de su distribución, historia natural y su estado de conservación.

9.
Front Microbiol ; 13: 975365, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36439792

RESUMEN

The integration of genomic information into microbial systematics along with physiological and chemotaxonomic parameters provides for a reliable classification of prokaryotes. In silico analysis of chemotaxonomic traits is now being introduced to replace characteristics traditionally determined in the laboratory with the dual goal of both increasing the speed of the description of taxa and the accuracy and consistency of taxonomic reports. Genomics has already successfully been applied in the taxonomic rearrangement of Geodermatophilaceae (Actinomycetota) but in the light of new genomic data the taxonomy of the family needs to be revisited. In conjunction with the taxonomic characterisation of four strains phylogenetically located within the family, we conducted a phylogenetic analysis of the whole proteomes of the sequenced type strains and established genotype-phenotype correlations for traits related to chemotaxonomy, cell morphology and metabolism. Results indicated that the four isolates under study represent four novel species within the genus Blastococcus. Additionally, the genera Blastococcus, Geodermatophilus and Modestobacter were shown to be paraphyletic. Consequently, the new genera Trujillonella, Pleomorpha and Goekera were proposed within the Geodermatophilaceae and Blastococcus endophyticus was reclassified as Trujillonella endophytica comb. nov., Geodermatophilus daqingensis as Pleomorpha daqingensis comb. nov. and Modestobacter deserti as Goekera deserti comb. nov. Accordingly, we also proposed emended descriptions of Blastococcus aggregatus, Blastococcus jejuensis, Blastococcus saxobsidens and Blastococcus xanthilyniticus. In silico chemotaxonomic results were overall consistent with wet-lab results. Even though in silico discriminatory levels varied depending on the respective chemotaxonomic trait, this approach is promising for effectively replacing and/or complementing chemotaxonomic analyses at taxonomic ranks above the species level. Finally, interesting but previously overlooked insights regarding morphology and ecology were revealed by the presence of a repertoire of genes related to flagellum synthesis, chemotaxis, spore production and pilus assembly in all representatives of the family. A rich carbon metabolism including four different CO2 fixation pathways and a battery of enzymes able to degrade complex carbohydrates were also identified in Blastococcus genomes.

10.
Front Microbiol ; 13: 1100319, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36741890

RESUMEN

[This corrects the article DOI: 10.3389/fmicb.2022.975365.].

11.
Syst Appl Microbiol ; 44(4): 126223, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-34157595

RESUMEN

Streptomyces thermoautotrophicus UBT1T has been suggested to merit generic status due to its phylogenetic placement and distinctive phenotypes among Actinomycetia. To evaluate whether 'S. thermoautotrophicus' represents a higher taxonomic rank, 'S. thermoautotrophicus' strains UBT1T and H1 were compared to Actinomycetia using 16S rRNA gene sequences and comparative genome analyses. The UBT1T and H1 genomes each contain at least two different 16S rRNA sequences, which are closely related to those of Acidothermus cellulolyticus (order Acidothermales). In multigene-based phylogenomic trees, UBT1T and H1 typically formed a sister group to the Streptosporangiales-Acidothermales clade. The Average Amino Acid Identity, Percentage of Conserved Proteins, and whole-genome Average Nucleotide Identity (Alignment Fraction) values were ≤58.5%, ≤48%, ≤75.5% (0.3) between 'S. thermoautotrophicus' and Streptosporangiales members, all below the respective thresholds for delineating genera. The values for genomics comparisons between strains UBT1T and H1 with Acidothermales, as well as members of the genus Streptomyces, were even lower. A review of the 'S. thermoautotrophicus' proteomic profiles and KEGG orthology demonstrated that UBT1T and H1 present pronounced differences, both tested and predicted, in phenotypic and chemotaxonomic characteristics compared to its sister clades and Streptomyces. The distinct phylogenetic position and the combination of genotypic and phenotypic characteristics justify the proposal of Carbonactinospora gen. nov., with the type species Carbonactinospora thermoautotrophica comb. nov. (type strain UBT1T, = DSM 100163T = KCTC 49540T) belonging to Carbonactinosporaceae fam. nov. within Actinomycetia.


Asunto(s)
Filogenia , Streptomyces , Actinobacteria , Técnicas de Tipificación Bacteriana , ADN Bacteriano/genética , Proteómica , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Streptomyces/clasificación
12.
Insects ; 12(6)2021 May 26.
Artículo en Inglés | MEDLINE | ID: mdl-34073280

RESUMEN

Tenthredinidae represents one of the external feeders of the most diverse superfamily, Tenthredinoidea, with diverse host plant utilization. In this study, four complete mitochondrial genomes (mitogenomes), those of Cladiucha punctata, Cladiucha magnoliae, Megabeleses magnoliae, and Megabeleses liriodendrovorax, are newly sequenced and comparatively analyzed with previously reported tenthredinid mitogenomes. The close investigation of mitogenomes and the phylogeny of Tenthredinidae leads us to the following conclusions: The subfamilial relationships and phylogenetic placements within Tenthredinidae are mostly found to be similar to the previously suggested phylogenies. However, the present phylogeny supports the monophyly of Megabelesesinae as a subfamily, with the sister-group placement of Cladiucha and Megabeleses outside of Allantinae. The occurrence of the same type of tRNA rearrangements (MQI and ANS1ERF) in the mitogenomes of Megabelesesinae species and the presence of apomorphic morphological characters also provide robust evidence for this new subfamily. The divergence and diversification times of the subfamilies appear to be directly related to colonization of the flowering plants following the Early Cretaceous. The origin time and diversification patterns of Megabelesesinae were also well matched with the divergence times of their host plants from Magnoliaceae.

13.
Zootaxa ; 4801(3): zootaxa.4801.3.3, 2020 Jun 19.
Artículo en Inglés | MEDLINE | ID: mdl-33056644

RESUMEN

An integrative taxonomic analysis of the Sphenomorphus stellatus group recovered a newly discovered museum specimen from Phu Quoc Island, Kien Giang Province, Vietnam as a new species most closely related to S. preylangensis from Phnom Chi in central Cambodia, approximately 175 km to the northeast. Most notably, S. phuquocensis sp. nov. lacks the derived condition of having black dorsal stripes that diagnose S. annamiticus-the sister species to S. preylangensis plus S. phuquocensis sp. nov. A BioGeoBEARS analysis recovered the ancestor of the S. stellatus group to likely have ranged across forested regions on an exposed Sunda Shelf from southwestern Indochina to Peninsular Malaysia prior to diverging into northern and southern lineages separated by the Gulf of Thailand. Episodic fluctuations in sea levels and concomitant changes in the physiography of the Mekong Delta contributed to the fragmented distribution within and between species of the northern lineage. Sphenomorphus phuquocensis sp. nov. represents the second species of reptile endemic to Phu Quoc Island.


Asunto(s)
Reptiles , Animales , Islas , Vietnam
14.
Zootaxa ; 4816(2): zootaxa.4816.2.2, 2020 Jul 16.
Artículo en Inglés | MEDLINE | ID: mdl-33055702

RESUMEN

An integrative taxonomic analysis of newly discovered populations of Hemiphyllodactylus from Indochina recovered a new species from Peninsular Thailand and two others from Laos. The new Thai species, Hemiphyllodactylus pardalis sp. nov. described herein, is the sister species to all other species in the newly designated Indochina clade and has a unique spotted contrasting dorsal pattern not seen in any other species of Hemiphyllodactylus. This, along with its elongate and gracile body morphology, renders it remarkably convergent on the Philippine gecko Pseudogekko smaragdinus despite the fact it is deeply nested within Hemiphyllodactylus. The description of this new species underscores the depauperate nature of Hemiphyllodactylus diversity throughout Indochina in general and Thailand in particular compared to neighboring upland areas of Myanmar and Peninsular Malaysia. This especially underscores the need for continued herpetofaunal field surveys in montane areas of western Thailand.


Asunto(s)
Ecosistema , Lagartos , Animales , Filipinas , Filogenia , Tailandia
15.
Zootaxa ; 4778(2): zootaxa.4778.2.8, 2020 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-33055826

RESUMEN

Pristimantis lassoalcalai Barrio-Amorós, Rojas-Runjaic Barros, 2010 is a poorly known terrarana, endemic to the eastern slope of Sierra de Perijá in Venezuela. Although a close relationship of this species with Tachiramantis has been suspected based on its overall morphological similarity, this relationship had not been tested so far. On the basis of molecular data (two fragments of the 12S and 16S mtDNA genes) obtained from the type series, we reconstruct its evolutionary relationships and establish its phylogenetic position as a member of Tachiramantis. Based on this phylogenetic hypothesis, we transfer Pristimantis lassoalcalai to Tachiramantis as Tachiramantis lassoalcalai comb. nov. In addition, we describe its advertisement call. This is the fourth known species of the genus and the second to which its vocalization is described.


Asunto(s)
Anuros , Vocalización Animal , Animales , Evolución Biológica , Filogenia
16.
PeerJ ; 8: e9652, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32879790

RESUMEN

The Somali Sengi or Somali Elephant-shrew ('Elephantulus' revoilii, Macroscelidea, Mammalia) has been considered a "lost species" and is primarily known from about 39 museum specimens, with no new vouchered occurrence records since the early 1970s. The scientific literature contains no data concerning living Somali Sengi individuals and the species' current Data Deficient conservation status is attributable to an absence of modern information. Almost everything that has been published about the species is derived from anatomical examinations of historic specimens, gleaned from museum collection notes, or inferred from the known habits and ecology of other sengi taxa. Here we report new evidence that the Somali Sengi is currently extant. These data include voucher specimens, georeferenced occurrence localities, body measurements, habitat parameters, and DNA sequences. While the species is historically documented as endemic to Somalia, these new records are from the neighboring Republic of Djibouti and thus expand the Somali Sengi's known range in the Horn of Africa. Furthermore, Djiboutian locality data near international borders suggests that the Somali Sengi is also a current inhabitant of both Somalia and Ethiopia. Criteria that inform conservation status assessments (e.g., suitable habitat contiguity and occurrence in wildlife protected areas) can be positively characterized in Djibouti and therefore bode well for the survival of the Somali Sengi species. New data also inform previously undocumented substrate and sheltering affiliations. DNA analyses indicate that the Somali Sengi is a descendant of the Macroscelidini lineage and therefore reveal that the species' referral to the genus Elephantulus is incompatible with sengi phylogeny. This taxonomic issue is resolved by recognizing a new genus replacement and recombinant binomial that redesignates the Somali Sengi as Galegeeska revoilii (gen. nov., nov. comb). An analysis of ancestral biogeography suggests that the Somali Sengi has inhabited the Horn of Africa for more than 5.4 million years-and the recognition of the species' phylogenetic ancestry appends the already remarkable biogeographic story of the Macroscelidini tribe.

17.
Front Microbiol ; 11: 468, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32373076

RESUMEN

The class Alphaproteobacteria is comprised of a diverse assemblage of Gram-negative bacteria that includes organisms of varying morphologies, physiologies and habitat preferences many of which are of clinical and ecological importance. Alphaproteobacteria classification has proved to be difficult, not least when taxonomic decisions rested heavily on a limited number of phenotypic features and interpretation of poorly resolved 16S rRNA gene trees. Despite progress in recent years regarding the classification of bacteria assigned to the class, there remains a need to further clarify taxonomic relationships. Here, draft genome sequences of a collection of genomes of more than 1000 Alphaproteobacteria and outgroup type strains were used to infer phylogenetic trees from genome-scale data using the principles drawn from phylogenetic systematics. The majority of taxa were found to be monophyletic but several orders, families and genera, including taxa recognized as problematic long ago but also quite recent taxa, as well as a few species were shown to be in need of revision. According proposals are made for the recognition of new orders, families and genera, as well as the transfer of a variety of species to other genera and of a variety of genera to other families. In addition, emended descriptions are given for many species mainly involving information on DNA G+C content and (approximate) genome size, both of which are confirmed as valuable taxonomic markers. Similarly, analysis of the gene content was shown to provide valuable taxonomic insights in the class. Significant incongruities between 16S rRNA gene and whole genome trees were not found in the class. The incongruities that became obvious when comparing the results of the present study with existing classifications appeared to be caused mainly by insufficiently resolved 16S rRNA gene trees or incomplete taxon sampling. Another probable cause of misclassifications in the past is the partially low overall fit of phenotypic characters to the sequence-based tree. Even though a significant degree of phylogenetic conservation was detected in all characters investigated, the overall fit to the tree varied considerably.

18.
Int J Parasitol Parasites Wildl ; 10: 281-288, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31867208

RESUMEN

Gigantorhynchus echinodiscus (Diesing, 1851) is a parasite of anteaters in South America. Although described by Diesing in 1851, there is still a lack of taxonomic and phylogenetic information regarding this species. In the present study, we redescribe G. echinodiscus collected from a giant anteater, Myrmecophaga tridactyla Linnaeus, 1758, from the Brazilian Cerrado (Savannah) in the State of São Paulo by light and scanning electron microscopy. In addition, phylogenies were inferred from partial DNA gene sequence of the nuclear large subunit ribosomal RNA gene (28S rRNA). We provide for the first time details of the proboscis with a crown having 18 large hooks and numerous small hooks, a lateral papilla at the base of the proboscis, a ringed pseudo-segmented body, large testes, cemented glands in pairs, and a non-segmented region in the posterior end of the body, which contributed to the diagnosis of the species. Molecular phylogenetic analyses recovered G. echinodiscus forming a well-supported monophyletic group with Mediorhynchus sp., which was congruent with morphological studies that allocate both genera within the family Gigantorhynchidae. In conclusion, the present work adds new morphological and molecular information, emphasizing the importance of adopting integrative taxonomic approaches in studies of Acanthocephala.

19.
Zootaxa ; 4683(3): zootaxa.4683.3.4, 2019 Oct 09.
Artículo en Inglés | MEDLINE | ID: mdl-31715918

RESUMEN

Molecular phylogenetic analyses of the sister species Sphenomorphus stellatus and S. praesignis based on the mitochondrial genes 12S and 16S rRNA recover the former as paraphyletic with respect to the latter in that a specimen of S. stellatus from the type locality in Peninsular Malaysia is more closely related to S. praesignis than to Indochinese populations of S. stellatus. Furthermore, the phylogeny indicates that the Indochinese populations represent two species, thus resulting in four major lineages within this clade. These relationships are consistent with multivariate and univariate analyses of morphological and discrete color pattern data which statistically define and diagnose the four lineages and together with the molecular data, provide the foundation for robust, testable, species-level hypotheses. As such, S. stellatus is herein restricted to Peninsular Malaysia; S. annamiticus is resurrected for the circum-continental populations ranging through southeastern Thailand, southern Cambodia, and southern Vietnam; a new species-S. preylangensis sp. nov.-is described from an isolated mountain, Phnom Chi, from the Prey Lang Wildlife Sanctuary in central Cambodia; and the taxonomy of S. praesignis remains unchanged. The description of S. preylangensis sp. nov. underscores the necessity to conserve this remnant of lowland evergreen rainforest in the Prey Lang Wildlife Sanctuary.


Asunto(s)
Lagartos , Animales , Cambodia , Lagartos/genética , Malasia , Filogenia , ARN Ribosómico 16S , Tailandia , Vietnam
20.
Front Microbiol ; 10: 2083, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31608019

RESUMEN

Although considerable progress has been made in recent years regarding the classification of bacteria assigned to the phylum Bacteroidetes, there remains a need to further clarify taxonomic relationships within a diverse assemblage that includes organisms of clinical, piscicultural, and ecological importance. Bacteroidetes classification has proved to be difficult, not least when taxonomic decisions rested heavily on interpretation of poorly resolved 16S rRNA gene trees and a limited number of phenotypic features. Here, draft genome sequences of a greatly enlarged collection of genomes of more than 1,000 Bacteroidetes and outgroup type strains were used to infer phylogenetic trees from genome-scale data using the principles drawn from phylogenetic systematics. The majority of taxa were found to be monophyletic but several orders, families and genera, including taxa proposed long ago such as Bacteroides, Cytophaga, and Flavobacterium but also quite recent taxa, as well as a few species were shown to be in need of revision. According proposals are made for the recognition of new orders, families and genera, as well as the transfer of a variety of species to other genera. In addition, emended descriptions are given for many species mainly involving information on DNA G+C content and (approximate) genome size, both of which can be considered valuable taxonomic markers. We detected many incongruities when comparing the results of the present study with existing classifications, which appear to be caused by insufficiently resolved 16S rRNA gene trees or incomplete taxon sampling. The few significant incongruities found between 16S rRNA gene and whole genome trees underline the pitfalls inherent in phylogenies based upon single gene sequences and the impediment in using ordinary bootstrapping in phylogenomic studies, particularly when combined with too narrow gene selections. While a significant degree of phylogenetic conservation was detected in all phenotypic characters investigated, the overall fit to the tree varied considerably, which is one of the probable causes of misclassifications in the past, much like the use of plesiomorphic character states as diagnostic features.

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