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1.
Ther Adv Musculoskelet Dis ; 16: 1759720X241234584, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38654732

RESUMO

Background: Subjects with a fragility fracture have an increased risk of a new fracture and should receive effective strategies to prevent new events. The medium-term to long-term strategy should be scheduled by considering the mechanisms of action in therapy and the estimated fracture risk. Objective: A systematic review was conducted to evaluate the sequential strategy in patients with or at risk of a fragility fracture in the context of the development of the Italian Guidelines. Design: Systematic review and meta-analysis. Data sources and methods: PubMed, Embase, and the Cochrane Library were investigated up to February 2021 to update the search of a recent systematic review. Randomized clinical trials (RCTs) that analyzed the sequential therapy of antiresorptive, anabolic treatment, or placebo in patients with or at risk of a fragility fracture were eligible. Three authors independently extracted data and appraised the risk of bias in the included studies. The quality of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation methodology. Effect sizes were pooled in a meta-analysis using fixed-effects models. The primary outcome was the risk of refracture, while the secondary outcome was the bone mineral density (BMD) change. Results: In all, 17 RCTs, ranging from low to high quality, met our inclusion criteria. A significantly reduced risk of fracture was detected at (i) 12 or 24 months after the switch from romosozumab to denosumab versus placebo to denosumab; (ii) 30 months from teriparatide to bisphosphonates versus placebo to bisphosphonates; and (iii) 12 months from romosozumab to alendronate versus the only alendronate therapy (specifically for vertebral fractures). In general, at 2 years after the switch from anabolic to antiresorptive drugs, a weighted BMD was increased at the lumbar spine, total hip, and femoral neck site. Conclusion: The Task Force formulated recommendations on sequential therapy, which is the first treatment with anabolic drugs or 'bone builders' in patients with very high or imminent risk of fracture.


A systematic review to evaluate the sequential therapy of antiresorptive (denosumab and bisphosphonate, such as alendronate, minodronate, risedronate, and etidronate), anabolic treatment (such as romosozumab, teriparatide), or placebo in patients with or at risk of a fragility fracture in the context of the development of the Italian Guidelines Subjects with previous fragility fractures should promptly receive effective strategies to prevent the risk of subsequent events. Indeed, patients with a fragility fracture have a doubled risk of a new fracture. For this reason, it is essential to provide adequate sequential therapy based on the mechanisms and the rapidity of action. A systematic review was performed to identify the sequential strategy in patients at high- or imminent-risk of (re)fracture and to support the Panel of the Italian Fragility Fracture Guideline in formulating recommendations. Our systematic review included seventeen studies mostly focused on women and enabled us to strongly recommend the anabolic drugs as first-line treatment. Specifically, for the sequential therapy from anabolic to antiresorptive treatment, there was a significant reduction in the risk of different types of fractures after the switch from romosozumab to denosumab versus placebo to denosumab. These findings were confirmed at 24 months after the switch. Considering the sequential treatment from antiresorptive to anabolic medications, there was a decreased risk of fracture 12 months after the switch from placebo to teriparatide versus bisphosphonate or antiresorptive to teriparatide. Moreover, a greater bone mineral density increase after the switch from anabolic to antiresorptive medications was shown in the lumbar spine, total hip, and femoral neck. The results of this systematic review and meta-analysis confirm that initial treatment with anabolic drugs produces substantial bone mineral density improvements, and the transition to antiresorptive drugs can preserve or even amplify the acquired benefit. These findings support the choice to treat very high-risk individuals with anabolic drugs first, followed by antiresorptive drugs.

5.
Animals (Basel) ; 13(21)2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37958151

RESUMO

Many studies on reptiles have been conducted across Madagascar but some areas are poorly known in terms of the diversity of reptiles such as the Bobaomby Complex in the northern tip of Madagascar. In February and March 2018, we conducted a biodiversity survey within five sites. This biological survey is to collect scientific information for helping new protected creations. Three main methods were used including pitfall trap, visual and acoustic searching along the transect and refuge examination. In total, we recorded 42 species including 5 chameleons, 8 skinks, 11 geckos, 16 snakes and 2 blinds snake species. All recorded species are endemic to Madagascar except Hemidactylus frenatus, Ebenavia inunguis and Phelsuma abbotti. Rare species known only from a few specimens have been recorded in the Bobaomby Complex: Heteroliodon fohy, Pseudoxyrhopus ambreensis, and Madascincus arenicola. Thirteen species are classified as threatened on the IUCN Red List, of which three are Critically Endangered: Paracontias minimus, Madascincus arenicola, and Paroedura lohatsara; three are Endangered: Heteroliodon fohy, Lycodryas inopinae, and Phisalixella variabilis; and seven are Vulnerable: Brookesia ebenaui, Furcifer petteri, Blaesodactylus boivini, Uroplatus ebenaui, Uroplatus henkeli, Liophidium therezieni and Flexiseps ardouini. Our results reveal the importance of the Bobaomby Complex for conserving reptile diversity and highlight the need to protect it.

6.
Ecol Evol ; 13(8): e10344, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37529593

RESUMO

Speciation rates vary substantially across the tree of life. These rates should be linked to the rate at which population structure forms if a continuum between micro and macroevolutionary patterns exists. Previous studies examining the link between speciation rates and the degree of population formation in clades have been shown to be either correlated or uncorrelated depending on the group, but no study has yet examined the relationship between speciation rates and population structure in a young group that is constrained spatially to a single-island system. We examine this correlation in 109 gemsnakes (Pseudoxyrhophiidae) endemic to Madagascar and originating in the early Miocene, which helps control for extinction variation across time and space. We find no relationship between rates of speciation and the formation rates of population structure over space in 33 species of gemsnakes. Rates of speciation show low variation, yet population structure varies widely across species, indicating that speciation rates and population structure are disconnected. We suspect this is largely due to the persistence of some lineages not susceptible to extinction. Importantly, we discuss how delimiting populations versus species may contribute to problems understanding the continuum between shallow and deep evolutionary processes.

7.
Zootaxa ; 5306(1): 97-115, 2023 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-37518534

RESUMO

Populations of phytotelmic frogs from northern Madagascar assigned to Guibemantis (Pandanusicola) pulcher are known to differ genetically from populations further south in the eastern rainforest belt of the island, but to date, their status has not been analyzed in depth. We combined molecular genetic data with an examination of color pattern to clarify the taxonomy of these frogs. DNA sequences of both mitochondrial and nuclear-encoded genes were consistently differentiated between the northern populations and those occurring further south. Uncorrected pairwise distance in the 16S rRNA gene was 3.7‒4.3% and thus at a level usually characterizing distinct frog species in Madagascar. Furthermore, the northern specimens were characterized by more and smaller purplish-brown spots on their green dorsal surface, and a less distinct brown patch on the flanks. Although fully conclusive evidence for the species status of the northern lineage from bioacoustic differences, sympatric occurrence or narrow hybrid zone is currently lacking, such species-level distinctness is currently the most likely hypothesis. We therefore name the northern populations as Guibemantis (Pandanusicola) pulcherrimus sp. nov. The new species is known from Makira (type locality) and Bemanevika, and specimens morphologically assignable to this taxon have also been recorded from Masoala, Marojejy and Anjanaharibe-Sud.


Assuntos
Pandanaceae , Animais , RNA Ribossômico 16S/genética , Filogenia , Pandanaceae/genética , Madagáscar , Anuros/genética
8.
Ecol Evol ; 13(3): e9914, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36937068

RESUMO

How environmental factors shape patterns of biotic diversity in tropical ecosystems is an active field of research, but studies examining the possibility of ecological speciation in terrestrial tropical ecosystems are scarce. We use the isolated rainforest herpetofauna on the Montagne d'Ambre (Amber Mountain) massif in northern Madagascar as a model to explore elevational divergence at the level of populations and communities. Based on intensive sampling and DNA barcoding of amphibians and reptiles along a transect ranging from ca. 470-1470 m above sea level (a.s.l.), we assessed a main peak in species richness at an elevation of ca. 1000 m a.s.l. with 41 species. The proportion of local endemics was highest (about 1/3) at elevations >1100 m a.s.l. Two species of chameleons (Brookesia tuberculata, Calumma linotum) and two species of frogs (Mantidactylus bellyi, M. ambony) studied in depth by newly developed microsatellite markers showed genetic divergence up the slope of the mountain, some quite strong, others very weak, but in each case with genetic breaks between 1100 and 1270 m a.s.l. Genetic clusters were found in transect sections significantly differing in bioclimate and herpetological community composition. A decrease in body size was detected in several species with increasing elevation. The studied rainforest amphibians and reptiles show concordant population genetic differentiation across elevation along with morphological and niche differentiation. Whether this parapatric or microallopatric differentiation will suffice for the completion of speciation is, however, unclear, and available phylogeographic evidence rather suggests that a complex interplay between ecological and allopatric divergence processes is involved in generating the extraordinary species diversity of Madagascar's biota. Our study reveals concordant patterns of diversification among main elevational bands, but suggests that these adaptational processes are only part of the complex of processes leading to species formation, among which geographical isolation is probably also important.

9.
Mol Phylogenet Evol ; 180: 107700, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36603697

RESUMO

The highly diverse snake superfamily Elapoidea is considered to be a classic example of ancient, rapid radiation. Such radiations are challenging to fully resolve phylogenetically, with the highly diverse Elapoidea a case in point. Previous attempts at inferring a phylogeny of elapoids produced highly incongruent estimates of their evolutionary relationships, often with very low statistical support. We sought to resolve this situation by sequencing over 4,500 ultraconserved element loci from multiple representatives of every elapoid family/subfamily level taxon and inferring their phylogenetic relationships with multiple methods. Concatenation and multispecies coalescent based species trees yielded largely congruent and well-supported topologies. Hypotheses of a hard polytomy were not retained for any deep branches. Our phylogenies recovered Cyclocoridae and Elapidae as diverging early within Elapoidea. The Afro-Malagasy radiation of elapoid snakes, classified as multiple subfamilies of an inclusive Lamprophiidae by some earlier authors, was found to be monophyletic in all analyses. The genus Micrelaps was consistently recovered as sister to Lamprophiidae. We establish a new family, Micrelapidae fam. nov., for Micrelaps and assign Brachyophis to this family based on cranial osteological synapomorphy. We estimate that Elapoidea originated in the early Eocene and rapidly diversified into all the major lineages during this epoch. Ecological opportunities presented by the post-Cretaceous-Paleogene mass extinction event may have promoted the explosive radiation of elapoid snakes.


Assuntos
Evolução Biológica , Serpentes , Animais , Filogenia , Serpentes/genética
10.
Evolution ; 77(4): 931-945, 2023 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-36688802

RESUMO

A fundamental assumption of evolutionary biology is that phylogeny follows a bifurcating process. However, hybrid speciation and introgression are becoming more widely documented in many groups. Hybrid inference studies have been historically limited to small sets of taxa, while exploration of the prevalence and trends of reticulation at deep time scales remains unexplored. We study the evolutionary history of an adaptive radiation of 109 gemsnakes in Madagascar (Pseudoxyrhophiinae) to identify potential instances of introgression. Using several network inference methods, we find 12 reticulation events within the 22-million-year evolutionary history of gemsnakes, producing 28% of the diversity for the group, including one reticulation that resulted in the diversification of an 18 species radiation. These reticulations are found at nodes with high gene tree discordance and occurred among parental lineages distributed along a north-south axis that share similar ecologies. Younger hybrids occupy intermediate contact zones between the parent lineages showing that post-speciation dispersal in this group has not eroded the spatial signatures of introgression. Reticulations accumulated consistently over time, despite drops in overall speciation rates during the Pleistocene. This suggests that while bifurcating speciation rates may decline as the result of species accumulation and environmental change, speciation by hybridization may be more robust to these processes.


Assuntos
Especiação Genética , Hibridização Genética , Filogenia , Madagáscar
11.
PLoS One ; 17(3): e0263764, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35358210

RESUMO

In the processes that give rise to new species, changes first occur at the population level. But with the continuous nature of the divergence process, change in biological properties delimiting the shift from "individuals of divergent populations" towards "individuals of distinct species", as well as abiotic factors driving the change, remain largely ambivalent. Here we study diversification processes at the population level in a semi-aquatic frog, Mantidactylus (Brygoomantis) bellyi, across the diverse vegetation types of Montagne d'Ambre National Park (MANP), Madagascar. Genetic diversity was assessed with seven newly developed microsatellite markers as well as mitochondrial DNA sequences and concordance with patterns of ecological, morphological, and bioacoustic divergence evaluated. We found M. bellyi lacking mitochondrial differentiation within MANP, while microsatellite datasets partitioned them into three highly differentiated, geographically separated subpopulations (with indications for up to five subpopulations). The molecular grouping-primarily clustering individuals by geographic proximity-was coincident with differences in mean depth and width of waters, suggesting a possible role of fluvial characteristics in genetic exchange in this stream-breeding species. Genetic clustering not consistent with differences in call properties, except for dominant call frequencies under the two-subpopulations model. Morphological divergence was mostly consistent with the genetic clustering; subpopulations strongly differed by their snout-vent length, with individuals from high-elevation subpopulations smaller than those from populations below 1000 m above sea level. These results exemplify how mountains and environmental conditions might primarily shape genetic and morphological divergence in frog populations, without strongly affecting their calls.


Assuntos
Anuros , DNA Mitocondrial , Animais , Anuros/anatomia & histologia , Anuros/genética , DNA Mitocondrial/genética , Variação Genética , Humanos , Madagáscar , Parques Recreativos , Filogenia
12.
Zootaxa ; 4938(4): zootaxa.4938.4.2, 2021 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-33756965

RESUMO

The genus Scaphiophryne (Anura: Microhylidae) contains at least nine species that, together with their probable sister genus Paradoxophyla, form the Madagascar-endemic subfamily Scaphiophryninae. Scaphiophryne are robust burrowing frogs with explosive breeding behavior and are characterized by a unique larval morphology, being intermediate between that of filter-feeding and generalized tadpole types. Based on tadpole morphology, the nominal subgenus Scaphiophryne can be distinguished from the subgenus Pseudohemisus, a clade occurring in arid biomes with a largely unsolved taxonomy and nomenclature. Here we combine a comprehensive molecular phylogeny of all scaphiophrynines based on five mitochondrial and two nuclear genes with a re-examination of the name-bearing type specimens of the seven species-level nomina assignable to the subgenus Pseudohemisus. Our molecular phylogeny supports monophyly of the two subgenera and assigns the enigmatic S. matsoko to the subgenus Scaphiophryne. In this subgenus, our analysis confirms all currently accepted species as independent evolutionary lineages based on concordant differentiation in mitochondrial and nuclear genes, and provides evidence for a combination of low mitochondrial divergence, distinct nuclear divergence, and high nuclear heterozygosity. Yet, contrary to previous hypotheses, we do not find evidence of ongoing hybridization. In the subgenus Pseudohemisus we find support for three clearly delimited species-level lineages, one of which contains two deep conspecific lineages that warrant further study. To stabilize the taxonomy in this subgenus, and considering the very poor state of preservation of several type series and the heterogeneity of some of them, we here designate lectotypes for the nomina: Hemisus obscurus Grandidier, 1872; Calophrynus calcaratus Mocquard, 1895; Pseudohemisus verrucosus Angel, 1930; Pseudohemisus longimanus Angel, 1930; and Pseudohemisus longimanus var. melanopleura Angel, 1934. Taxonomically, we accept Scaphiophryne brevis (Boulenger, 1896) as a well-defined species; restrict S. calcarata (Mocquard, 1995) to the southern lineage of the S. calcarata complex; resurrect Hemisus obscurus Grandidier, 1872 (previously considered to be a dubious name or nomen inquirendum) as Scaphiophryne obscura to refer to the western and north-western lineage of the S. calcarata complex; consider Pseudohemisus verrucosus Angel, 1930 as junior synonym of Scaphiophryne brevis; and consider Pseudohemisus longimanus Angel, 1930 and Pseudohemisus longimanus var. melanopleura Angel, 1934 as junior synonyms of Scaphiophryne obscura. Finally, to accelerate taxonomic progress, we (i) outline a set of criteria by which such old and ambiguous nomina can be applied to known lineages, (ii) suggest that the International Code of Zoological Nomenclature should slightly broaden the conditions under which neotypes are to be designated, and (iii) propose to redouble discussions on the introduction of the concept of the epitype to zoology.


Assuntos
Anuros , Ecossistema , Animais , Anuros/genética , Larva , Filogenia
13.
Sci Rep ; 10(1): 19109, 2020 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-33154397

RESUMO

Taxonomic progress is often hindered by intrinsic factors, such as morphologically cryptic species that require a broad suite of methods to distinguish, and extrinsic factors, such as uncertainties in the allocation of scientific names to species. These uncertainties can be due to a wide variety of factors, including old and poorly preserved type specimens (which contain only heavily degraded DNA or have lost important diagnostic characters), inappropriately chosen type specimens (e.g. juveniles without diagnostic characters) or poorly documented type specimens (with unprecise, incorrect, or missing locality data). Thanks to modern sequencing technologies it is now possible to overcome many such extrinsic factors by sequencing DNA from name-bearing type specimens of uncertain assignment and assigning these to known genetic lineages. Here, we apply this approach to frogs of the Mantidactylus ambreensis complex, which was recently shown to consist of two genetic lineages supported by concordant differentiation in mitochondrial and nuclear genes. These lineages co-occur on the Montagne d'Ambre Massif in northern Madagascar but appear to have diverged in allopatry. We use a recently published bait set based on three mitochondrial markers from all known Malagasy frog lineages to capture DNA sequences from the 127-year-old holotype of Mantidactylus ambreensis Mocquard, 1895. With the obtained sequences we are able to assign the name M. ambreensis to the lowland lineage, which is rather widespread in the rainforests of northern Madagascar, leaving the microendemic high-elevation lineage on Montagne d'Ambre in north Madagascar in need of description. We describe this species as Mantidactylus ambony sp. nov., differing from M. ambreensis in call parameters and a smaller body size. Thus, using target enrichment to obtain DNA sequence data from this old specimen, we were able to resolve the extrinsic (nomenclatural) hindrances to taxonomic resolution of this complex. We discuss the broad-scale versatility of this 'barcode fishing' approach, which can draw on the enormous success of global DNA barcoding initiatives to quickly and efficiently assign type specimens to lineages.


Assuntos
Anuros/genética , Código de Barras de DNA Taxonômico , Marcadores Genéticos/genética , Filogenia , Animais , Tamanho Corporal/genética , Madagáscar
14.
Zootaxa ; 4895(2): zootaxa.4895.2.5, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-33756904

RESUMO

The northern part of Madagascar is well known for its high species diversity and endemism. Exceptional species richness is related to the existence of large forest blocks and mountain complexes. These areas shelter a diverse variety of habitats occupied by a wide diversity of species, including leaf-tailed geckos of the genus Uroplatus. Based on morphological and molecular evidence, we here formally name two evolutionary lineages as new species that previously had been considered as candidate species (Uroplatus spp. Ca3 and Ca4), both small-sized species of the Uroplatus ebenaui group. Genetically, both new species are related to U. finiavana with a genetic divergence (uncorrected pairwise distance) of 10.3-12.8% in a fragment of the mitochondrial 16S rRNA gene, and separated from each other by 10.3-10.7%. Uroplatus fangorn sp. nov. is described from the Marojejy massif and is also known from Andrevorevo, Lohanandroranga and Sorata; it is similar to U. ebenaui and U. fetsy but is distinguishable by its rather short tail and only partially black pigmented oral mucosa. Uroplatus fivehy sp. nov. is described from the Sorata Massif and is wider-ranging, occurring in an area from Marotandrano and Makira to Sorata, comprising Marojejy, Anjanaharibe-Sud, Ankitsika and Betaolana; it is morphologically similar to U. finiavana but distinguishable by tail size and shape. Both newly described species are found in rainforest from mid to high elevation and range respectively from 840-1417 m for U. fivehy sp nov. and 1300-1800 m for U. fangorn sp. nov. According to their respective geographical distributions, we propose to classify the two new species as Vulnerable under the IUCN Red List criteria, due to their occurrence in some forests outside of the protected area network plus the continuing decline of forest patches in the north of Madagascar.


Assuntos
Lagartos , Animais , Lagartos/genética , Madagáscar , Filogenia , RNA Ribossômico 16S/genética , Floresta Úmida
15.
Mol Phylogenet Evol ; 144: 106700, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31809850

RESUMO

Madagascar's biota is characterized by a high degree of microendemism at different taxonomic levels, but how colonization and in-situ speciation contribute to the assembly of local species communities has rarely been studied on this island. Here we analyze the phylogenetic relationships of riparian frogs of the Mantidactylus ambreensis species complex, which is distributed in the north of Madagascar and was originally described from Montagne d'Ambre, an isolated mountain of volcanic origin, currently protected within Montagne d'Ambre National Park (MANP). Data from mitochondrial DNA, and phylogenomic data from FrogCap, a sequence capture method, independently confirm that this species complex is monophyletic within the subgenus Ochthomantis, and identify two main clades within it. These two clades are separated by 5.6-6.8% pairwise distance in the mitochondrial 16S rRNA gene and co-occur in MANP, with one distributed at high elevations (940-1375 m a.s.l.) and the other at lower elevations (535-1010 m a.s.l.), but show almost no haplotype sharing in the nuclear RAG1 gene. This occurrence in syntopy without admixture confirms them as independent evolutionary lineages that merit recognition as separate species, and we here refer to them as high-elevation (HE) and low-elevation (LE) lineage; they will warrant taxonomic assessment to confidently assign the name ambreensis to one or the other. Populations of the M. ambreensis complex from elsewhere in northern Madagascar all belong to the LE lineage, although they do occur over a larger elevational range than in Montagne d'Ambre (285-1040 m a.s.l.). Within LE there are several phylogroups (LE1-LE4) of moderately deep divergence (1.5-2.8% in 16S), but phylogroup LE4 that occurs in MANP has a deeply nested phylogenetic position, as recovered separately by mitochondrial and sequence capture datasets. This suggests that HE and LE did not diverge by a local fission of lower and upper populations, but instead arose through a more complex biogeographic scenario. The branching pattern of phylogroups LE1-LE4 shows a clear south-to-north phylogeographic pattern. We derive from these results a testable hypothesis of vicariant speciation that restricted the HE lineage to MANP and the LE candidate species to a climatic refugium further south, with subsequent northwards range expansion and secondary colonization of MANP by LE. These results provide an example for complex assembly of local microendemic amphibian faunas on Madagascar.


Assuntos
Anuros/classificação , Anuros/genética , Especiação Genética , Simpatria/fisiologia , Animais , Núcleo Celular/genética , DNA Mitocondrial/genética , Genes RAG-1 , Madagáscar , Filogenia , Filogeografia , RNA Ribossômico 16S
16.
Zootaxa ; 4683(1): zootaxa.4683.1.4, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31715936

RESUMO

Previous studies on leaf-tailed geckos of the genus Uroplatus identified a lineage from the Ankarana karst massif in northern Madagascar as genetically highly divergent, but only fragmentary information was available on these geckos. Here, we provide an integrative analysis based on molecular and morphological data, including a newly collected specimen from this locality. Phylogenetic analysis placed the Ankarana lineage sister to U. ebenaui, but with a surprisingly high genetic divergence of over 19% uncorrected pairwise distance in the mitochondrial 16S rRNA gene. We formally describe the Ankarana lineage as Uroplatus fetsy sp. nov. and provide new information on the distribution and genetic differentiation of its sister species, Uroplatus ebenaui. Based on DNA sequences of newly examined samples this latter species is confirmed as widespread, ranging from low-elevation dry forests from Beanka in western Madagascar to Forêt d'Ambre and Analalava/Fanambana in northern Madagascar, and thus far has not been found in the Ankarana Massif, where U. fetsy occurs.


Assuntos
Lagartos , Animais , Lagartos/genética , Madagáscar , Parques Recreativos , Filogenia , RNA Ribossômico 16S
17.
Syst Biol ; 68(6): 918-936, 2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31188455

RESUMO

Processes leading to spectacular diversity of both form and species on islands have been well-documented under island biogeography theory, where distance from source and island size are key factors determining immigration and extinction resistance. But far less understood are the processes governing in situ diversification on the world's mega islands, where large and isolated land masses produced morphologically distinct radiations from related taxa on continental regions. Madagascar has long been recognized as a natural laboratory due to its isolation, lack of influence from adjacent continents, and diversification of spectacular vertebrate radiations. However, only a handful of studies have examined rate shifts of in situ diversification for this island. Here, we examine rates of diversification in the Malagasy snakes of the family Pseudoxyrhophiinae (gemsnakes) to understand if rates of speciation were initially high, enhanced by diversification into distinct biomes, and associated with key dentition traits. Using a genomic sequence-capture data set for 366 samples, we determine that all previously described and newly discovered species are delimitable and therefore useful candidates for understanding diversification trajectories through time. Our analysis detected no shifts in diversification rate between clades or changes in biome or dentition type. Remarkably, we demonstrate that rates of diversification of the gemsnake radiation, which originated in Madagascar during the early Miocene, remained steady throughout the Neogene. However, we do detect a significant slowdown in diversification during the Pleistocene. We also comment on the apparent paradox where most living species originated in the Pleistocene, despite diversification rates being substantially higher during the earlier 15 myr.


Assuntos
Biodiversidade , Filogenia , Serpentes/classificação , Animais , Especiação Genética , Madagáscar , Serpentes/anatomia & histologia
18.
Zootaxa ; 4545(4): 563-577, 2019 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-30790891

RESUMO

The Marojejy Massif in northern Madagascar is a constant source of herpetological surprises. Herein we describe a new species of leaf-mimicking leaf-tailed gecko, Uroplatus finaritra sp. nov., based on morphological and molecular phylogenetic evidence. This new species inhabits the rainforests of Marojejy National Park at low elevations and is morphologically similar to Uroplatus phantasticus, but differs by having a larger body size, relatively shorter tail, and dark-red pigmentation of the oral mucosa. Molecular data reveals a distance of 14.0-14.7% in the 16S rRNA gene to U. phantasticus, and haplotype sharing in the c-mos nuclear gene only with species of much shorter tails (i.e., with U. kelirambo and two undescribed candidate species). Similar to other members of the leaf-mimicking Uroplatus species in northern Madagascar, Uroplatus finaritra sp. nov. likely has a small geographic distribution, and is currently known only from the lowland rainforests of Marojejy. We discuss the value of the buccal mucosa colouration and tail dimensions of Uroplatus as taxonomic characters, and the potential drivers of their evolution. In order to reduce the risk of international trade under incorrect species names we suggest that exported CITES species should be obligatorily accompanied by information about their precide geographic origin within Madagascar.


Assuntos
Lagartos , Parques Recreativos , Animais , Madagáscar , Filogenia , RNA Ribossômico 16S
19.
Sci Rep ; 8(1): 13273, 2018 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-30185838

RESUMO

Over 75% of abdominal aortic aneurysms harbor an intraluminal thrombus, and increasing evidence suggests that biologically active thrombus contributes to the natural history of these potentially lethal lesions. Thrombus formation depends on the local hemodynamics, which in turn depends on morphological features of the aneurysm and near vasculature. We previously presented a hemodynamically motivated "thrombus formation potential" that predicts where and when thrombus might form. Herein, we combine detailed studies of the three-dimensional hemodynamics with methods of sparse grid collocation and interpolation via kriging to examine roles of five key morphological features of aneurysms on thrombus formation: lesion diameter, axial position, length, curvature, and renal artery position. Computational simulations suggest that maximum diameter is a key determinant of thrombogenicity, but other morphological features modulate this dependence. More distally located lesions tend to have a higher thrombus formation potential and shorter lesions tend to have a higher potential than longer lesions, given the same aneurysmal dilatation. Finally, movement of vortical structures through the infrarenal aorta and lesion can significantly affect thrombogenicity. Formation of intraluminal thrombus within an evolving abdominal aortic aneurysm thus depends on coupled morphological features, not all intuitive, and computational simulations can be useful for predicting thrombogenesis.


Assuntos
Aneurisma da Aorta Abdominal/patologia , Aneurisma Aórtico/patologia , Trombose/patologia , Aorta Abdominal/patologia , Aneurisma Aórtico/metabolismo , Fenômenos Biomecânicos , Simulação por Computador , Hemodinâmica/fisiologia , Humanos , Trombose/metabolismo
20.
Parasit Vectors ; 11(1): 330, 2018 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-29859123

RESUMO

BACKGROUND: Few details are available on the consumption of ectoparasites, specifically bat flies (Diptera: Nycteribiidae and Streblidae), by their chiropteran hosts while grooming. Such details are important to document consumption rates of ectoparasites by their bat host provide details on the dynamics of host-parasite interactions. We present data on ectoparasite consumption rates for an endemic Malagasy fruit bat (Pteropodidae: Rousettus madagascariensis) occupying a cave day roost colony in northern Madagascar. Using quantified behavioral analyses, grooming and associated ingestion rates were measured from infrared videos taken in close proximity to day-roosting bats. The recorded individual bats could be visually identified to age (adult, juvenile) and sex (male, female), allowing analyses of the proportion of time these different classes allocated to consuming ectoparasites via auto-grooming (self) or allo-grooming (intraspecific) per 10 min video recording session. These figures could then be extrapolated to estimates of individual daily consumption rates. RESULTS: Based on video recordings, adults spent significantly more time auto-grooming and allo-grooming than juveniles. The latter group was not observed consuming ectoparasites. Grooming rates and the average number of ectoparasites consumed per day did not differ between adult males and females. The mean extrapolated number consumed on a daily basis for individual adults was 37 ectoparasites. When these figures are overlaid on the estimated number of adult Rousettus occurring at the roost site during the dry season, the projected daily consumption rate was 57,905 ectoparasites. CONCLUSIONS: The details presented here represent the first quantified data on bat consumption rates of their ectoparasites, specifically dipterans. These results provide new insights in host-parasite predation dynamics. More research is needed to explore the mechanism zoonotic diseases isolated from bat flies might be transmitted to their bat hosts, specifically those pathogens that can be communicated via an oral route.


Assuntos
Comportamento Animal , Quirópteros/parasitologia , Dípteros/fisiologia , Ectoparasitoses/veterinária , Interações Hospedeiro-Parasita , Animais , Cavernas , Ectoparasitoses/parasitologia , Feminino , Asseio Animal , Masculino
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