- Thermal Niche Differentiation in the Benthic Diatom Cylindrotheca closterium (Bacillariophyceae) Complex. [Journal Article]
- FMFront Microbiol 2019; 10:1395
- Coastal waters are expected to undergo severe warming in the coming decades. Very little is known about how diatoms, the dominant primary producers in these habitats, will cope with these changes. We…
Coastal waters are expected to undergo severe warming in the coming decades. Very little is known about how diatoms, the dominant primary producers in these habitats, will cope with these changes. We investigated the thermal niche of Cylindrotheca closterium, a widespread benthic marine diatom, using 24 strains collected over a wide latitudinal gradient. A multi-marker phylogeny in combination with a species delimitation approach shows that C. closterium represents a (pseudo)cryptic species complex, and this is reflected in distinct growth response patterns in terms of optimum growth temperature, maximum growth rate, and thermal niche width. Strains from the same clade displayed a similar thermal response, suggesting niche conservation between closely related strains. Due to their lower maximum growth rate and smaller thermal niche width, we expect the polar species to be particularly sensitive to warming, and, in the absence of adaptation, to be replaced with species from lower latitudes.
- Boomeranging around Australia: Historical biogeography and population genomics of the anti-equatorial fish Microcanthus strigatus (Teleostei: Microcanthidae). [Journal Article]
- MEMol Ecol 2019 Jul 10
- The geographic distributions of marine fishes have been shaped by ancient vicariance and ongoing dispersal events. Some species exhibit anti-equatorial distributions, inhabiting temperate regions on …
The geographic distributions of marine fishes have been shaped by ancient vicariance and ongoing dispersal events. Some species exhibit anti-equatorial distributions, inhabiting temperate regions on both sides of the tropics while being absent from equatorial latitudes. The perciform fish Microcanthus strigatus (the stripey) exhibits such a distribution, with disjunct populations occurring in East Asia, Hawaii, Western Australia, and the southwest Pacific. Here we examine the historical biogeography and evolutionary history of M. strigatus, based on more than 80 specimens sampled from the four major populations. We analyse 36 morphological characters, three mitochondrial markers, and two sets of 7120 and 12,771 single-nucleotide polymorphisms from the nuclear genome. Our results suggest that M. strigatus represents a cryptic species complex comprising at least two genetically distinct populations worthy of species-level recognition, with one population exhibiting strong genetic structuring but with intermittent, historical gene flow. We provide evidence for a southwest Pacific origin for the ancestral Microcanthus and explain how past connectivity between these regions might have given rise to the relationships observed in present-day marine fauna. Our ancestral range reconstructions and molecular-clock analyses support a southwest Pacific centre of origin for Microcanthus, with subsequent colonization of Western Australia through the Bass Strait followed by trans-equatorial dispersals to the Northern Hemisphere during the Pleistocene. Our results detail an anti-tropical dispersal pattern that is highly unusual and previously undocumented, thereby emphasizing the importance of integrative systematics in the evaluation of widespread species. This article is protected by copyright. All rights reserved.
- Qualitative vs. Quantitative Methods in Psychiatric Research: Updated. [Journal Article]
- MMMethods Mol Biol 2019; 2011:23-37
- Since the incipiency of psychiatry as a medical specialty, the "holy grail" has been neuroscience-based diagnostic system and treatment strategies, but this lofty, yet necessary, goal has eluded the …
Since the incipiency of psychiatry as a medical specialty, the "holy grail" has been neuroscience-based diagnostic system and treatment strategies, but this lofty, yet necessary, goal has eluded the greatest minds for centuries. Now, with advances in molecular genetics and resting-state neuroimaging, neuroscience-based diagnosis and treatment are now more possible than ever. However, clinical symptomatology, longitudinal course, and delimitation of illnesses (i.e., phenotypic classification) remain indispensable for responsible, reproducible, and meaningful use of these new methodologies.
- The Importance of the Biopsy Technique in the Diagnosis of Histoid Leprosy. [Journal Article]
- AJAm J Dermatopathol 2019 Jun 28
- Histoid leprosy (HL) was originally described by Wade in 1963 and is regarded as a rare variant of lepromatous leprosy (LL). These characteristic clinical lesions are firm, deeply adhered nodules wit…
Histoid leprosy (HL) was originally described by Wade in 1963 and is regarded as a rare variant of lepromatous leprosy (LL). These characteristic clinical lesions are firm, deeply adhered nodules with features reminiscent of dermatofibromas or keloids in a background of apparently healthy skin. The main histopathological findings described are the presence of spindle cell histiocytes immersed in a richly collagenized background, usually forming a nodular pattern of infiltration with sharply delimitation and positive staining for acid-fast bacilli. The classical form of HL lesions should be devoid of foam histiocytes and globi. However, we and other authors noticed that in most of the cases, despite characteristic clinical features, histopathology depicts a mixture of LL and HL patterns. Therefore, we present a case with clinical features similar to HL in which an excisional scalpel biopsy of a nodule demonstrated features of classical LL in the center of the lesion and features of HL in the periphery, highlighting that a proper biopsy technique could enhance the ability of the dermatopathologist to histopathologically diagnose cases of HL. In cases in which HL is clinically suspected, we advocate replacing the usual 4-mm incisional punch biopsy by a broader elliptical scalpel biopsy, encompassing the totality of the lesion whenever possible to achieve a reliable representation of the pathologic process.
- Evidence for cryptic diversification in a rupicolous forest-dwelling gecko (Gekkonidae: Afroedura pondolia) from a biodiversity hotspot. [Journal Article]
- MPMol Phylogenet Evol 2019 Jun 29; 139:106549
- We assess the phylogeographic structure and test several species delimitation methods in the forest-living Pondo flat-gecko, Afroedura pondolia, by sampling specimens from across the entire distribut…
We assess the phylogeographic structure and test several species delimitation methods in the forest-living Pondo flat-gecko, Afroedura pondolia, by sampling specimens from across the entire distribution in the Eastern Cape and KwaZulu-Natal provinces of South Africa. Phylogenetic results, using Bayesian inferences and maximum likelihood, from the combined mitochondrial and nuclear DNA sequence data derived from four partial loci (ND4, cyt b, PRLR and RAG1), suggest the presence of four geographically discrete clades, which represent candidate species. We applied four species-delimitation methods (ABGD, bGMYC, PTP and STACEY), the results of which were largely incongruent in the number of putative species nested within A. pondolia. Multivariate morphological analyses indicate statistically significant differences among the four candidate species, corroborating the presence of four cryptic species within A. pondolia. Divergence-time estimates suggest that cladogenesis was driven by forest fragmentation from the late Miocene to the Plio/Pleistocene with the onset of more pronounced xeric climatic conditions causing forest fragmentation.
- Identification of Subterranean Termite Genus, Reticulitermes (Blattodea: Rhinotermitidae) in Taiwan. [Journal Article]
- JEJ Econ Entomol 2019 Jul 02
- Species identification in the genus Reticulitermes is often difficult because of ambiguous morphological characters. Challenges in Reticulitermes spp. recognition have also been encountered in East A…
Species identification in the genus Reticulitermes is often difficult because of ambiguous morphological characters. Challenges in Reticulitermes spp. recognition have also been encountered in East Asia, including Taiwan. Because of unknown Reticulitermes taxa in Taiwan and the possible origin of alien Reticulitermes kanmonensis Takematsu in Japan and Korea, reexamining Reticulitermes fauna in Taiwan is imperative. To clarify the Reticulitermes fauna in Taiwan, this study applied two mitochondrial genes (cytochrome oxidase subunit II [COII] and 16S rDNA) and morphological characters for species delimitation. Reticulitermes specimens collected from 63 localities across the main and adjacent islands of Taiwan were analyzed. Phylogenetic analyses, morphological comparisons, and ecological traits suggested the existence of three species in Taiwan: Reticulitermes flaviceps (Oshima), R. kanmonensis, and Reticulitermes leptomandibularis Hsia and Fan. Altitudinal distributions among the three Reticulitermes termites tended to differ: R. flaviceps adapted to low hills, but R. kanmonensis and R. leptomandibularis occurred in medium mountainous areas. The combined data, including haplotype diversities and distribution range, suggest that 1) R. flaviceps is an endemic species and only found in Taiwan; 2) R. kanmonensis and R. leptomandibularis are both native species in Taiwan and China; 3) Japanese R. kanmonensis populations originated from southern China and/or Taiwan and that Korean populations were possibly introduced from Japan.
- Pristimantis in the Eastern Brazilian Amazon: DNA barcoding reveals underestimated diversity in a megadiverse genus. [Journal Article]
- MDMitochondrial DNA A DNA Mapp Seq Anal 2019 Jul 02; :1-8
- The genus Pristimantis has the highest species diversity among all terrestrial vertebrates, with most species observed in the Andean region and the Guiana Shield. Even with the recent description of …
The genus Pristimantis has the highest species diversity among all terrestrial vertebrates, with most species observed in the Andean region and the Guiana Shield. Even with the recent description of a new species, only P. latro, P. dundeei and P. zimmermanae occur in the south of the Amazon River. The lack of taxonomists specialized in the field leads to the propagation of dubious terminologies (e.g. Pristimantis sp1, Pristimantis sp2, P. aff. Fenestratus and P. gr. conspicillatus) or even misidentification of species, resulting in erroneous species distributions. In this study, we applied the Automatic Barcode Gap Discovery (ABGD) algorithm for the delimitation of candidate species and values of genetic distances using the mitochondrial marker Cytochrome Oxidase Subunit I (COI), proposed in the barcode methodology, where values greater than 10% are considered as indicative of different species. We found large genetic distances between P. latro and Pristimantis sp1 Unconfirmed Candidate Species - UCS1 (21%), and between P. altamazonicus and Pristimantis sp2 UCS2 (14%). The ABGD method recognized UCS1 and UCS2 as distinct species. Pristimantis sp. UCS1 and UCS2 in the east of the Brazilian Amazon are indicated as candidate species. We suggest greater sampling of Pristimantis sp. UCS1 and UCS2, integrating morphology and bioacoustics to solve the taxonomic status in the east of the Brazilian Amazon.
- The Interplay between Incipient Species and Social Polymorphism in the Desert Ant Cataglyphis. [Journal Article]
- SRSci Rep 2019 Jul 01; 9(1):9495
- In social insects, due to considerable polyphenism as well as high level of hybridization, the delimitation of species can be challenging. The genus Cataglyphis presents a high level of diversificati…
In social insects, due to considerable polyphenism as well as high level of hybridization, the delimitation of species can be challenging. The genus Cataglyphis presents a high level of diversification, making it an excellent model with which to study evolutionary paths. Israel appears to be a "hot spot" for recent speciation in this genus. Although previous studies have described multiple species of Cataglyphis in Israel, a recent genetic study has questioned the existence of some of these historically described species. The present study focuses on an apparent species complex, the C. niger species complex which includes C. niger, C. savigyi, and C. drusus that are distinguishable by their mitochondrial DNA (and therefore named mitotypes) but not by their nuclear DNA. Using a multi-method approach (genetics, chemistry and behavior), we show that these mitotypes also differ in their social structures and are readily distinguishable by their cuticular hydrocarbons profiles. While most populations of the different mitotypes are allopatric, at our study site they are sympatric, but nonetheless maintain the observed differences between them. This raises the evolutionary question: Are these incipient species that have diverged with gene flow, or is this a case of social and chemical polymorphism that is maintained within a single species? Unveiling the interplay between social polyphenism and species segregation is at the core of evolutionary biology.
- Tonantzin, a New Genus of Bess Beetle (Coleoptera, Passalidae) from a Montane Subtropical Forest in Central Mexico, with a Review of the Taxonomic Significance of the Mesofrontal Structure in Proculini. [Journal Article]
- IInsects 2019 Jun 28; 10(7)
- Mexico has the third highest diversity of passalid beetles in the World. Here we describe Tonantzin new genus, a new monotypic genus, potentially endemic to the mountains of central Mexico. The new g…
Mexico has the third highest diversity of passalid beetles in the World. Here we describe Tonantzin new genus, a new monotypic genus, potentially endemic to the mountains of central Mexico. The new genus is diagnosed by a new configuration of characters from the mesofrontal structure (MFS) in addition to other characters. The MFS in Passalidae has been treated either as a composite complex character or a combination of individual characters. Using a broad taxonomic sample within Proculini, we discuss the taxonomic and systematic implications of the MFS for the tribe. We define the MFS type tepetl. Given the importance of the MFS for passalid taxonomy we propose a new delimitation of the structure using boundaries based on internal and external head structures. We argue that the treatment of the MFS as a complex character better captures the nature of this structure but we ultimately find a need to standardize the way in which this structure is described in the taxonomic literature and used in phylogenetic analyses.
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- Cytogenetics and DNA barcode reveal an undescribed Apareiodon species (Characiformes: Parodontidae). [Journal Article]
- GMGenet Mol Biol 2019 Jun 27
- Parodontidae is a small group of fish and some species are particularly difficult to identify due to the lack of sufficiently consistent morphological traits. Cytogenetically, the species possess 2n …
Parodontidae is a small group of fish and some species are particularly difficult to identify due to the lack of sufficiently consistent morphological traits. Cytogenetically, the species possess 2n = 54 chromosomes and are either sex-homomorphic or sex-heteromorphic (regarding its chromosomes). We evaluated data on color, tooth morphology, cytogenetics, and mitochondrial markers (COI) in Apareiodon specimens from the Aripuanã River (Amazon basin) and the results were compared to other congeneric taxa. Morphological results show an overlap of body color and tooth morphology to other known Apareiodon. The cytogenetics data showed that the 2n = 54 chromosomes, 50 m/sm + 4 st and, a ZZ/ZW sex chromosome system in Apareiodon sp. are common to other species of the genus. However, the number and chromosomal localization of the 45S ribosomal and pPh2004 satellite DNA sites, in addition to W chromosome localization of the pPh2004 appear to be exclusive cytogenetic features in Apareiodon sp. Our phylogenetic tree revealed well-supported clades and confirmed, by barcode species delimitation analysis, a new Molecular Operational Taxonomic Unit (MOTU) for Apareiodon sp. (Aripuanã River). As a whole, the above features support the occurrence of a new species of the Apareiodon, thus far unknown for the Parodontidae.