Abstract:BackgroundThe family Reduviidae (Hemiptera: Heteroptera), or assassin bugs, is among the most diverse families of the true bugs, with more than 6,000 species. The subfamily Triatominae (kissing bugs) is noteworthy not simply because it is the only subfamily of the Reduviidae whose members feed on vertebrate blood but particularly because all 147 known members of the subfamily are potential Chagas disease vectors. Due to the epidemiological relevance of these species and the lack of an efficient treatment and v… Show more
“…Moreover, we argue that this was a unique event in the karyotype evolution of the Triatoma from South America, because, in addition to T. melanocephala and T. vitticeps , the only species that also presents fragmentation of the X chromosome is T. tibiamaculata 2n = 23 (20A + X 1 X 2 Y) [38]. However, the analysis provided by Justi et al [19] allows us emphasise that this species inherited this number of chromosomes from the common ancestor shared with the Panstrongylus (a genus in which most of the species also have 23 chromosomes).Fig. 2Karyotype evolution of the South American subcomplexes.…”
Section: Resultsmentioning
confidence: 99%
“…However, these species exhibit several similar characteristics, including morphological [27], cytogenetic [14], and phylogenetic [19] features, similarities which support the creation of a new subcomplex. Thus, this study aimed to describe, for the first time, the T. vitticeps subcomplex, highlighting the main phenotypic and genotypic characteristics that support the grouping of these species and how this subcomplex is distinct from the others present in South America.…”
BackgroundTriatomines have been grouped into complexes and subcomplexes based largely on morphological and geographical distribution. Although these groupings are not formally recognised as taxonomic ranks, they are likely monophyletic. However, recent studies have demonstrated that some subcomplexes from South America did not form monophyletic groups, and reorganisations have been suggested. One suggested reorganisation is to exclude Triatoma vitticeps, T. melanocephala, and T. tibiamaculata from the T. brasiliensis subcomplex. However, T. vitticeps and T. melanocephala exhibit several similar characteristics, including morphologic, cytogenetic, and phylogenetic features, a factor which supports the creation of a new subcomplex. Thus, this study aimed to describe the T. vitticeps subcomplex.Results
T. vitticeps and T. melanocephala are sister species and share a phylogenetic relationship, several similar morphological characteristics, the same composition of constitutive heterochromatin (Xs CG-rich and Y AT-rich), the same karyotype (2n = 20A + X1X2X3Y), and the same meiotic behaviour during spermatogenesis. Based on karyosystematics, for example, the T. vitticeps subcomplex may differ from all of the other subcomplexes from South America, as well as from the Rhodniini tribe and the genus Panstrongylus. We argue that the case of agmatoploidy involving the X chromosome was responsible for the karyotype divergence of this subcomplex in relation to the other South America subcomplexes.ConclusionsBased on the phenotypic characteristics (morphology) and genotypes (cytogenetics and molecular features), we propose the creation of the monophyletic T. vitticeps subcomplex, which we believe is distinct from all other subcomplexes from South America.
“…Moreover, we argue that this was a unique event in the karyotype evolution of the Triatoma from South America, because, in addition to T. melanocephala and T. vitticeps , the only species that also presents fragmentation of the X chromosome is T. tibiamaculata 2n = 23 (20A + X 1 X 2 Y) [38]. However, the analysis provided by Justi et al [19] allows us emphasise that this species inherited this number of chromosomes from the common ancestor shared with the Panstrongylus (a genus in which most of the species also have 23 chromosomes).Fig. 2Karyotype evolution of the South American subcomplexes.…”
Section: Resultsmentioning
confidence: 99%
“…However, these species exhibit several similar characteristics, including morphological [27], cytogenetic [14], and phylogenetic [19] features, similarities which support the creation of a new subcomplex. Thus, this study aimed to describe, for the first time, the T. vitticeps subcomplex, highlighting the main phenotypic and genotypic characteristics that support the grouping of these species and how this subcomplex is distinct from the others present in South America.…”
BackgroundTriatomines have been grouped into complexes and subcomplexes based largely on morphological and geographical distribution. Although these groupings are not formally recognised as taxonomic ranks, they are likely monophyletic. However, recent studies have demonstrated that some subcomplexes from South America did not form monophyletic groups, and reorganisations have been suggested. One suggested reorganisation is to exclude Triatoma vitticeps, T. melanocephala, and T. tibiamaculata from the T. brasiliensis subcomplex. However, T. vitticeps and T. melanocephala exhibit several similar characteristics, including morphologic, cytogenetic, and phylogenetic features, a factor which supports the creation of a new subcomplex. Thus, this study aimed to describe the T. vitticeps subcomplex.Results
T. vitticeps and T. melanocephala are sister species and share a phylogenetic relationship, several similar morphological characteristics, the same composition of constitutive heterochromatin (Xs CG-rich and Y AT-rich), the same karyotype (2n = 20A + X1X2X3Y), and the same meiotic behaviour during spermatogenesis. Based on karyosystematics, for example, the T. vitticeps subcomplex may differ from all of the other subcomplexes from South America, as well as from the Rhodniini tribe and the genus Panstrongylus. We argue that the case of agmatoploidy involving the X chromosome was responsible for the karyotype divergence of this subcomplex in relation to the other South America subcomplexes.ConclusionsBased on the phenotypic characteristics (morphology) and genotypes (cytogenetics and molecular features), we propose the creation of the monophyletic T. vitticeps subcomplex, which we believe is distinct from all other subcomplexes from South America.
“…Indeed, our finding of the divergent taxon in a single cave system in Belize supports this hypothesis (although more extensive sampling is necessary to confirm this), and other cave populations are monophyletic with T. dimidiata s.s. Work has just begun on understanding the environmental and geological forces that have separated the Triatominae (Justi et al, 2016) and specifically T. dimidiata taxa (Gómez-Palacio et al, 2015). Clarity of how many taxa are under the T. dimidiata umbrella will facilitate these studies.…”
The widespread and diverse Triatoma dimidiata is the kissing bug species most important for Chagas disease transmission in Central America and a secondary vector in Mexico and northern South America. Its diversity may contribute to different Chagas disease prevalence in different localities and has led to conflicting systematic hypotheses describing various populations as subspecies or cryptic species. To resolve these conflicting hypotheses, we sequenced a nuclear (internal transcribed spacer 2, ITS-2) and mitochondrial gene (cytochrome b) from an extensive sampling of T. dimidiata across its geographic range. We evaluated the congruence of ITS-2 and cyt b phylogenies and tested the support for the previously proposed subspecies (inferred from ITS-2) by: (1) overlaying the ITS-2 subspecies assignments on a cyt b tree and, (2) assessing the statistical support for a cyt b topology constrained by the subspecies hypothesis. Unconstrained phylogenies inferred from ITS-2 and cyt b are congruent and reveal three clades including two putative cryptic species in addition to T. dimidiata sensu stricto. Neither the cyt b phylogeny nor hypothesis testing support the proposed subspecies inferred from ITS-2. Additionally, the two cryptic species are supported by phylogenies inferred from mitochondrially-encoded genes cytochrome c oxidase I and NADH dehydrogenase 4. In summary, our results reveal two cryptic species. Phylogenetic relationships indicate T. dimidiata sensu stricto is not subdivided into monophyletic clades consistent with subspecies. Based on increased support by hypothesis testing, we propose an updated systematic hypothesis for T. dimidiata based on extensive taxon sampling and analysis of both mitochondrial and nuclear genes.
“…Recently, Justi et al (2014Justi et al ( , 2016 claim that although the complexes and subcomplexes show no taxonomic validity they must be monophyletic groups. Thus, the authors presented a phylogenetic reconstruction for the species groupings proposed by Schofield and Galvão (2009) and observed that many groups are not monophyletic (brasiliensis, maculata, matogrossensis, flavida and sordida subcomplexes).…”
Section: Scientific Notementioning
confidence: 99%
“…Recently, by means of dated phylogeny was supported that the ancestral of Nesotriatoma arrived in the Antillean islands approximately 14.8-18.8 millions of years (associated with rodent subfamily Capromyinae) (Justi et al, 2016) and by phylogenetic analysis we can see that Nesotriatoma and Panstrongylus share an ancestor comum (Justi et al, 2014(Justi et al, , 2016. Was suggested that the ancestor of these vectors presented karyotype 2n = 23 and that during the divergence and karyotype evolution of species occurred one event punctual of simploidy in the autosome of P. megistus and agmatoploidy in the X sex chromosome of P. lutzi (Alevi and Azeredo-Oliveira, 2018).…”
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