Calochroa miroklichai sp. nov., a new species from Thailand with rectification of different concepts of Calochroa tritoma (Schmidt-Goebel) and comparisons to similar species. (Coleoptera: Cicindelidae).

A new species of the genus Calochroa Hope, 1838 is described as new to science from Thailand. Two different concepts of Calochroa tritoma (Schmidt-Goebel, 1846) are rectified here, stating that the correct concept of C. tritoma (fully corresponding to the holotype in NMPC) is that presented by Naviaux (1991), Naviaux & Pinratana (2004) and Klícha & Durícek (2021), while C. tritoma sensu Pearson et al. (2020) is described here as Calochroa miroklichai sp. nov. Accordingly, C. tritoma sensu Acciavatti & Pearson (1989) represents a different, probably an undescribed species. C. anometallescens (W. Horn, 1893) and Calochroa laurae (Gestro, 1893), as well as the new species, have been partly misidentified as C. tritoma in collections. The occurrence of C. tritoma is newly restricted to Thailand and Myanmar only. The above-mentioned species, as well as Calochroa fumikoae Wiesner & Phyu, 2019 are compared to C. miroklichai sp. nov. Calochroa goebeli (W. Horn, 1895), treated in literature either as a "variety" or junior synonym of C. anometallescens (or confused with C. tritoma), proved to represent a separate species. Some other taxa and discrepancies within the genus are discussed. Habitats and characters of several species versus their relations to the genus Cosmodela Rivalier, 1961 also are annotated. Habitus and diagnostic characters are illustrated in colour photographs, and photographs of the habitus and labels of type specimens of C. tritoma, C. laurae and C. goebeli are presented here for the first time.

A new species of Pristimantis (Anura: Strabomantidae) from white-sand forests of central Amazonia, Brazil.

The white-sand ecosystems in the Solimões-Negro Interfluve are among the less studied in Amazonia. Recent herpetological surveys conducted west of Manaus, Brazil (central Amazonia) indicate that white-sand forests host a unique anuran fauna comprising habitat specialized and endemic species. In the present study we describe a new species of rain frog belonging to the Pristimantis unistrigatus species group from the white-sand forest locally called "campinarana" (thin-trunked forests with canopy height below 20 m). The new species is phylogenetically close to rain frogs from western Amazonian lowlands (P. delius, P. librarius, P. matidiktyo and P. ockendeni). It differs from its closest relatives mainly by its size (male SVL of 17.3-20.1 mm, n = 16; female SVL of 23.2-26.5 mm, n = 6), presence of tympanum, tarsal tubercles and dentigerous processes of vomers, its translucent groin without bright colored blotches or marks, and by its advertisement call (composed of 5-10 notes, call duration of 550-1,061 ms, dominant frequency of 3,295-3,919 Hz). Like other anuran species recently discovered in the white-sand forests west of Manaus, the new species seems to be restricted to this peculiar ecosystem.

The bisphenol S contamination level observed in human follicular fluid affects the development of porcine oocytes.

Bisphenol S (BPS), the main replacement for bisphenol A (BPA), is thought to be toxic, but limited information is available on the effects of Bisphenol S on ovarian follicles. In our study, we demonstrated the presence of Bisphenol S in the follicular fluid of women at a concentration of 22.4 nM. The effect of such concentrations of Bisphenol S on oocyte maturation and subsequent embryo development is still unknown. Therefore, we focused on the effect of Bisphenol S on in vitro oocyte maturation, fertilization, and embryo development. As a model, we used porcine oocytes, which show many physiological similarities to human oocytes. Oocytes were exposed to Bisphenol S concentrations similar to those detected in female patients in the ART clinic. We found a decreased ability of oocytes to successfully complete meiotic maturation. Mature oocytes showed an increased frequency of meiotic spindle abnormalities and chromosome misalignment. Alarming associations of oocyte Bisphenol S exposure with the occurrence of aneuploidy and changes in the distribution of mitochondria and mitochondrial proteins were demonstrated for the first time. However, the number and quality of blastocysts derived from oocytes that successfully completed meiotic maturation under the influence of Bisphenol S was not affected.

Phylogenomics of Anguis and Pseudopus (Squamata, Anguidae) indicates Balkan-Apennine mitochondrial capture associated with the Messinian event.

A dated phylogenetic hypothesis on the evolutionary history of the extant taxa of the Western Palearctic lizards Anguis and Pseudopus is revised using genome-wide nuclear DNA and mitogenomes. We found overall concordance between nuclear and mitochondrial DNA phylogenies, with one significant exception - the Apennine A. veronensis. In mitochondrial DNA, this species forms a common clade with the earliest diverging lineage, the southern Balkan endemic A. cephallonica, while it clusters together with A. fragilis in nuclear DNA. The nuclear phylogeny conforms to the morphology, which is relatively similar between A. veronensis and A. fragilis. The most plausible explanation for the mitonuclear discordance is ancient mitochondrial capture from the Balkan ancestor of A. cephallonica to the Apennine population of the A. fragilis-veronensis ancestor. We hypothesize that this capture occurred only in a geographically restricted population. The dating of this presumed mitochondrial introgression and capture coincides with the Messinian event, when the Balkan and Apennine Peninsulas were presumably largely connected. The dated nuclear phylogenomic reconstruction estimated the divergence of A. cephallonica around 12 Mya, while the sister clade representing the A. fragilis species complex consisting of the sister species A. fragilis-A. veronensis and A. colchica-A. graeca further diversified around 7 Mya. The depth of nuclear divergence among the evolutionary lineages of Pseudopus (0.5-1.2 Mya) supports their subspecies status.

Testing for Phylogenetic Signal in Single-Cell RNA-Seq Data.

Phylogenetic methods are emerging as a useful tool to understand cancer evolutionary dynamics, including tumor structure, heterogeneity, and progression. Most currently used approaches utilize either bulk whole genome sequencing or single-cell DNA sequencing and are based on calling copy number alterations and single nucleotide variants (SNVs). Single-cell RNA sequencing (scRNA-seq) is commonly applied to explore differential gene expression of cancer cells throughout tumor progression. The method exacerbates the single-cell sequencing problem of low yield per cell with uneven expression levels. This accounts for low and uneven sequencing coverage and makes SNV detection and phylogenetic analysis challenging. In this article, we demonstrate for the first time that scRNA-seq data contain sufficient evolutionary signal and can also be utilized in phylogenetic analyses. We explore and compare results of such analyses based on both expression levels and SNVs called from scRNA-seq data. Both techniques are shown to be useful for reconstructing phylogenetic relationships between cells, reflecting the clonal composition of a tumor. Both standardized expression values and SNVs appear to be equally capable of reconstructing a similar pattern of phylogenetic relationship. This pattern is stable even when phylogenetic uncertainty is taken in account. Our results open up a new direction of somatic phylogenetics based on scRNA-seq data. Further research is required to refine and improve these approaches to capture the full picture of somatic evolutionary dynamics in cancer.

Preferred ß-lactone synthesis can explain high rate of false-negative results in the detection of OXA-48-like carbapenemases.

The resistance to carbapenems is usually mediated by enzymes hydrolyzing ß-lactam ring. Recently, an alternative way of the modification of the antibiotic, a ß-lactone formation by OXA-48-like enzymes, in some carbapenems was identified. We focused our study on a deep analysis of OXA-48-like-producing Enterobacterales, especially strains showing poor hydrolytic activity. In this study, well characterized 74 isolates of Enterobacterales resistant to carbapenems were used. Carbapenemase activity was determined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), liquid chromatography/mass spectrometry (LC-MS), Carba-NP test and modified Carbapenem Inactivation Method (mCIM). As meropenem-derived ß-lactone possesses the same molecular weight as native meropenem (MW 383.46 g/mol), ß-lactonization cannot be directly detected by MALDI-TOF MS. In the spectra, however, the peaks of m/z = 340.5 and 362.5 representing decarboxylated ß-lactone and its sodium adduct were detected in 25 out of 35 OXA-48-like producers. In the rest 10 isolates, decarboxylated hydrolytic product (m/z = 358.5) and its sodium adduct (m/z = 380.5) have been detected. The peak of m/z = 362.5 was detected in 3 strains co-producing OXA-48-like and NDM-1 carbapenemases. The respective signal was identified in no strain producing class A or class B carbapenemase alone showing its specificity for OXA-48-like carbapenemases. Using LC-MS, we were able to identify meropenem-derived ß-lactone directly according to the different retention time. All strains with a predominant ß-lactone production showed negative results of Carba NP test. In this study, we have demonstrated that the strains producing OXA-48-like carbapenemases showing false-negative results using Carba NP test and MALDI-TOF MS preferentially produced meropenem-derived ß-lactone. We also identified ß-lactone-specific peak in MALDI-TOF MS spectra and demonstrated the ability of LC-MS to detect meropenem-derived ß-lactone.

Anguimorpha as a model group for studying the comparative heart morphology among Lepidosauria: Evolutionary window on the ventricular septation.

The group Anguimorpha represents one of the most unified squamate clades in terms of body plan, ecomorphology, ecophysiology and evolution. On the other hand, the anguimorphs vary between different habitats and ecological niches. Therefore, we focused on the group Anguimorpha to test a possible correlation between heart morphology and ecological niche with respect to phylogenetic position in Squamata with Sphenodon, Salvator, and Pogona as the outgroups. The chosen lepidosaurian species were investigated by microCT. Generally, all lepidosaurs had two well-developed atria with complete interatrial septum and one ventricle divided by ventricular septa to three different areas. The ventricles of all lepidosaurians had a compact layer and abundant trabeculae. The compact layer and trabeculae were developed in accordance with particular ecological niche of the species, the trabeculae in nocturnal animals with low metabolism, such as Sphenodon, Heloderma or Lanthanotus were more massive. On the other hand athletic animals, such as varanids or Salvator, had ventricle compartmentalization divided by three incomplete septa. A difference between varanids and Salvator was found in compact layer thickness: thicker in monitor lizards and possibly linked to their mammalian-like high blood pressure, and the level of ventricular septation. In summary: heart morphology varied among clades in connection with the ecological niche of particular species and it reflects the phylogenetic position in model clade Anguimorpha. In the absence of fossil evidence, this is the closest approach how to understand heart evolution and septation in clade with different cardiac compartmentalization levels.

Effect of Bisphenol S on testicular tissue after low-dose lactation exposure.

Exposure to endocrine disruptors such as bisphenols, can lead to and be the explanation for idiopathic infertility. In our study, we assessed the effect of exposure to bisphenol S (BPS) via breast milk on the testicular tissue health of adult male mice. Lactating dams were exposed to BPS through drinking water (0.216 ng g bw/day and 21.6 ng g bw/day) from post-natal day 0-15. Although there was no significant difference in testicular histopathology between the control and experimental groups, we observed an increase in the number of tight and gap junctions in the blood-testis barrier (BTB) of adult mice after lactation BPS exposure. Moreover, there was an increase in oxidative stress markers in adult testicular tissue of mice exposed via breast milk. Our lactation model indicates that breast milk is a route of exposure to an endocrine disruptor that can be responsible for idiopathic male infertility through the damage of the BTB and weakening of oxidative stress resistance in adulthood.

Evidence of endogenously produced hydrogen sulfide (H2S) and persulfidation in male reproduction.

Persulfidation contributes to a group of redox post-translational modifications (PTMs), which arise exclusively on the sulfhydryl group of cysteine as a result of hydrogen sulfide (H2S) action. Redox-active molecules, including H2S, contribute to sperm development; therefore, redox PTMs represent an extremely important signalling pathway in sperm life. In this path, persulfidation prevents protein damage caused by irreversible cysteine hyperoxidation and thus maintains this signalling pathway. In our study, we detected both H2S and its production by all H2S-releasing enzymes (cystathionine γ-lyase (CTH), cystathionine ß-synthase (CBS), and 3-mercaptopyruvate sulfurtransferase (MPST)) in male reproduction, including spermatozoa. We provided evidence that sperm H2S leads to persulfidation of proteins, such as glyceraldehyde-3-phosphate dehydrogenase, tubulin, and anchor protein A-kinase. Overall, this study suggests that persulfidation, as a part of the redox signalling pathway, is tightly regulated by enzymatic H2S production and is required for sperm viability.

Accounting for Errors in Data Improves Divergence Time Estimates in Single-cell Cancer Evolution.

Single-cell sequencing provides a new way to explore the evolutionary history of cells. Compared to traditional bulk sequencing, where a population of heterogeneous cells is pooled to form a single observation, single-cell sequencing isolates and amplifies genetic material from individual cells, thereby preserving the information about the origin of the sequences. However, single-cell data are more error-prone than bulk sequencing data due to the limited genomic material available per cell. Here, we present error and mutation models for evolutionary inference of single-cell data within a mature and extensible Bayesian framework, BEAST2. Our framework enables integration with biologically informative models such as relaxed molecular clocks and population dynamic models. Our simulations show that modeling errors increase the accuracy of relative divergence times and substitution parameters. We reconstruct the phylogenetic history of a colorectal cancer patient and a healthy patient from single-cell DNA sequencing data. We find that the estimated times of terminal splitting events are shifted forward in time compared to models which ignore errors. We observed that not accounting for errors can overestimate the phylogenetic diversity in single-cell DNA sequencing data. We estimate that 30-50% of the apparent diversity can be attributed to error. Our work enables a full Bayesian approach capable of accounting for errors in the data within the integrative Bayesian software framework BEAST2.

Tuberous sclerosis complex: a complex case.

Tuberous sclerosis complex (TSC) is an inheritable disorder characterized by the formation of benign yet disorganized tumors in multiple organ systems. Germline mutations in the TSC1 (hamartin) or more frequently TSC2 (tuberin) genes are causative for TSC. The malignant manifestations of TSC, pulmonary lymphangioleiomyomatosis (LAM) and renal angiomyolipoma (AML), may also occur as independent sporadic perivascular epithelial cell tumor (PEComa) characterized by somatic TSC2 mutations. Thus, discerning TSC from the copresentation of sporadic LAM and sporadic AML may be obscured in TSC patients lacking additional features. In this report, we present a case study on a single patient initially reported to have sporadic LAM and a mucinous duodenal adenocarcinoma deficient in DNA mismatch repair proteins. Moreover, the patient had a history of Wilms' tumor, which was reclassified as AML following the LAM diagnosis. Therefore, we investigated the origins and relatedness of these tumors. Using germline whole-genome sequencing, we identified a premature truncation in one of the patient's TSC2 alleles. Using immunohistochemistry, loss of tuberin expression was observed in AML and LAM tissue. However, no evidence of a somatic loss of heterozygosity or DNA methylation epimutations was observed at the TSC2 locus, suggesting alternate mechanisms may contribute to loss of the tumor suppressor protein. In the mucinous duodenal adenocarcinoma, no causative mutations were found in the DNA mismatch repair genes MLH1, MSH2, MSH6, or PMS2 Rather, clonal deconvolution analyses were used to identify mutations contributing to pathogenesis. This report highlights both the utility of using multiple sequencing techniques and the complexity of interpreting the data in a clinical context.

Response of Three Miscanthus × giganteus Cultivars to Toxic Elements Stress: Part 2, Comparison between Two Growing Seasons.

The positive impact on restoring soil functionality, decreasing toxic elements (TE) bioaccessibility, and enhancing soil physicochemical and biological parameters established a consensus on considering a Miscanthus × giganteus convenient species for phytomanaging wide TE contaminated areas. Nevertheless, information about the plant's mode of reaction to elevated soil multi-TE concentrations is still scarce. For the sake of investigating the miscanthus response to stressful TE concentrations, an ex-situ pot experiment was initiated for 18 months, with three miscanthus cultivars referred to as B, U, and A planted in soils with gradient Cd, Pb, and Zn concentrations. A non-contaminated control soil was introduced as well, and plants were cultivated within. Results revealed that the long exposure to increasing soil TE concentrations caused the number of tillers per plant to decline and the TE concentrations in the leaves to boost progressively with the soil contamination. The photosynthetic pigments (chlorophyll a, b, and carotenoids) were negatively affected as well. However, the phenolic compounds, flavonoids, tannins, and anthocyanins, along with the antioxidant enzymatic activities of superoxide dismutase, ascorbate peroxidase, and glutathione reductase elevated progressively with the TE concentration and exposure duration. Conclusively, miscanthus plants demonstrated an intensified and synchronized antioxidative activity against the TE concentration.

First exact record and phylogenetic position of the gecko Ptyodactylus hasselquistii (Squamata: Phyllodactylidae) from Lebanon.

The genus Ptyodactylus comprises 12 species distributed in North Africa and the Middle East. The most widely distributed species of the genus, Ptyodactylus hasselquistii, is known for its great morphological and genetic diversity, and ranges from Sudan and Egypt through Israel and Jordan towards Saudi Arabia and Yemen. In 1905 the first specimen of P. hasselquistii was collected from Lebanon, described later as a distinct subspecies, Ptyodactylus hasselquistii krameri. Here we provide a second record of P. hasselquistii from Lebanon collected in 2010, which represents the first exact record of the species in Lebanon in over 105 years. We use morphological comparisons and genetic analyses of two markers to account for the phylogenetic position of the new specimen within Ptyodactylus and to evaluate the taxonomic status of P. h. krameri. This integrative examination revealed a close association of the Lebanese specimen with nominotypic P. hasselquistii populations from Egypt and Sudan suggesting a relatively recent introduction from that general area. Similar morphological characteristics between the two Lebanese specimens and those from Egypt, and identical genetic sequences, suggest rejecting subspecific status of the Lebanese population and synonymizing the name Ptyodactylus hasselquistii krameri with the name Ptyodactylus hasselquistii.

The phylogeny of Dendropsophini (Anura: Hylidae: Hylinae).

The relationships of the hyline tribe Dendropsophini remain poorly studied, with most published analyses dealing with few of the species groups of Dendropsophus. In order to test the monophyly of Dendropsophini, its genera, and the species groups currently recognized in Dendropsophus, we performed a total evidence phylogenetic analysis. The molecular dataset included sequences of three mitochondrial and five nuclear genes from 210 terminals, including 12 outgroup species, the two species of Xenohyla, and 93 of the 108 recognized species of Dendropsophus. The phenomic dataset includes 46 terminals, one per species (34 Dendropsophus, one Xenohyla, and 11 outgroup species). Our results corroborate the monophyly of Dendropsophini and the reciprocal monophyly of Dendropsophus and Xenohyla. Some species groups of Dendropsophus are paraphyletic (the D. microcephalus, D. minimus, and D. parviceps groups, and the D. rubicundulus clade). On the basis of our results, we recognize nine species groups; for three of them (D. leucophyllatus, D. microcephalus, and D. parviceps groups) we recognize some nominal clades to highlight specific morphology or relationships and facilitate species taxonomy. We further discuss the evolution of oviposition site selection, where our results show multiple instances of independent evolution of terrestrial egg clutches during the evolutionary history of Dendropsophus.

Taxonomic and nomenclatorial revision within the Neotropical genera of the subtribe Odontocheilina W. Horn in a new sense-23. Odontocheila parafemoralis sp. nov., a new species of the O. cajennensis species-complex (Coleoptera: Cicindelidae).

A new species of the genus Odontocheila Laporte de Castelnau, 1834 is described from Brazil as Odontocheila parafemoralis sp. nov. Along with other species previously treated as subspecies of O. cajennensis (Fabricius, 1787), the new species is classified here as a species of the O. cajennensis species-complex (within the O. cajennensis species-group). It was commonly confused in collections with O. bipunctata (Fabricius, 1792) and O. femoralis Chaudoir, 1860. Specimens from Itaituba, Rio Tapajoz, Pará (the type locality of the new species) were previously considered by the present author to be aberrant adults of O. oseryi (Lucas, 1857) and were also included within the species in the taxonomic revision of the genus (Moravec 2018). A recent examination of numerous specimens from Itaituba has revealed that they represent an undescribed species, which is diagnostically separated from all taxa of the O. cajennensis species-complex. Consequently, it is described here as new to science. Illustrations of the habitus, diagnostic characters and variability of the new species and distinguishing characters of similar species are presented in colour photographs. A revised key to species of the O. cajennensis species-complex (within the complete O. cajennensis species-group) is presented with reference to the taxonomic revision of the genus (Moravec 2018). An essential map of distribution is also given.

New or rare Madagascar tiger beetles-20. Pogonostoma (Bathypogonum) horimichioi sp. nov. and supplemented characters of P. (B.) levigatum levigatum (W. Horn) and P. (B.) levigatum lucens Rivalier (Coleoptera: Cicindelidae).

Pogonostoma (Bathypogonum) horimichioi sp. nov. is described as new to science from western Madagascar. Apart from a detailed description, illustrations in colour photographs of the habitus, diagnostic characters and habitat of the new species are introduced. A rectified differential diagnosis of the subgenus Bathypogonum Jeannel, 1946 is performed. The new species is compared to other two hitherto known taxa of the subgenus Bathypogonum (in its narrow original concept and sensu Moravec 2007), which are P. (B.) levigatum levigatum W. Horn, 1908 and P. (B.) levigatum lucens Rivalier, 1970. Differential diagnoses of the two taxa with illustrations of their habitus and important distinguishing characters in colour photographs are presented. References to their detailed redescriptions and illustrations, as well as to those of the subgenera Neopogonum Moravec, 2007 and Parapogonum Moravec, 2007 in the monograph of the genus Pogonostoma by Moravec (2007) are given. Essential maps of distribution are also presented.

New or rare Madagascar tiger beetles-21. Physodeutera (Microlepidia) propripenis sp. nov., Ph. (M.) marginemaculata (W. Horn) and Ph. (M.) peyrierasi Rivalier (Coleoptera: Cicindelidae).

A new species of the Madagascan endemic genus Physodeutera Lacordaire, 1842 is described from northern Madagascar as Physodeutera (Microlepidia) propripenis sp. nov. The new species is compared to similar Physodeutera (Microlepidia) marginemaculata (W. Horn, 1934) and Physodeutera (Microlepidia) peyrierasi Rivalier, 1967. Apart from a detailed description of the new species, illustrations in colour photographs of its habitus, diagnostic characters and habitat are introduced. Differential diagnoses of the two similar species, as well as illustrations of their habitus and distinguishing characters in colour photographs are presented with references to their redescriptions and illustrations based on type and other relevant specimens in the monograph of the genus (Moravec 2002a). A revised key to the subgenus Microlepidia Rivalier, 1967 is presented in order to supplement the key previously published in the monograph. Essential maps of the distribution of the three species are also given.

Phenotypic differentiation of the slow worm lizards (Squamata: Anguis) across their contact zone in Central Europe.

BACKGROUND: The application of molecular-phylogenetic approaches to taxonomy has had a dramatic effect on our understanding of the diversity of reptiles. These approaches have allowed researchers to reveal previously hidden lineages as well as taxonomic overestimation in morphologically plastic taxa. Slow worms, legless lizards of the genus Anguis (Squamata: Anguidae), were previously considered to comprise either one or two species, and morphology-based intraspecific taxonomy of Anguis fragilis remained controversial throughout the 20th century. After the discovery of deep genetic divergences within the genus, its taxonomy was reconsidered, and as a result, five extant species have been recognized. In order to better understand the patterns of their interspecific differentiation, here we studied phenotypic differences between the two most widespread of them-A. fragilis and A. colchica, and their putative hybrids across the contact zone of both species in Central Europe. METHODS: We used multivariate and univariate statistics and analyzed ten metric, eleven meristic, and six categorical phenotypic variables in material comprising a total of 326 individuals. We also genotyped individuals from the contact zone for one mitochondrial and two nuclear DNA fragments in order to delineate the distribution of individuals of hybrid and non-hybrid origin. The clines in morphological traits were studied using HZAR. RESULTS: We show that the two species are morphologically differentiated. Anguis fragilis has a less robust head, fewer scales covering the body, lower frequency of the external ear opening presence, lower frequency of separated prefrontal scales, higher frequency of prefrontal scales in contact with each other, and body coloration more similar to the juvenile coloration than A. colchica. Slow worms from the contact/hybrid zone are characterized by an intermediate morphology, with more similarities to A. fragilis than to A. colchica. DISCUSSION: None of the analyzed characters alone proved to be fully diagnostic, although more than 90% of all individuals could be successfully assigned to one or another species based on numbers of scales around the body. Our results indicate concordant, coincident, and steep clines in character states change. We present several hypotheses on the origin and evolutionary maintenance of the morphological divergence between both species and suggest that different evolutionary histories of the taxa rather than recently acting selection explain the observed morphological variation.

New or rare Madagascar tiger beetles-18. Pogonostoma (Pogonostoma) ondravybirali sp. nov., elaborated redescriptions of P. (P.) atrorotundatum, P. (P.) densisculptum and P. (Microstenocera) fabiocassolai (Coleoptera: Cicindelidae).

Pogonostoma (Pogonostoma) ondravybirali sp. nov. from southwestern Madagascar is described as new to science. The new species is placed to a large P. (Pogonostoma) elegans species-group (sensu Moravec 2007) along with seven other mutually similar species which are recognized within this species-group as a species-complex of P. (P.) alluaudi W. Horn, 1898. An elaborated redescription of the most similar P. (P.) atrorotundatum W. Horn, 1934 is given. A revised key to the P. (P.) elegans species-group is presented in order to supplement the key in the monograph of the genus Pogonostoma Klug, 1835 by Moravec (2007). First description of male characters of P. (Pogonostoma) densisculptum Moravec, 2003 (belonging to P. (P.) gibbosum species-group sensu Moravec 2007) and first description of female characters of P. (Microstenocera) fabiocassolai Moravec, 2003 (of the P. (M.) minimum species-group sensu Moravec 2007) are introduced. Type and other specimens of the presented species are illustrated in colour photographs of their habitus, diagnostic characters and variability (including two diagnostic characters of P. (P.) gibbosum Rivalier, 1970). Essential maps of the distribution of the treated species in Madagascar are given.