Morphological Differences Research Articles

Phenotypic, genomic, and transcriptomic heterogeneity in a pancreatic cancer cell line.

To evaluate the suitability of the MIA PaCa-2 cell line for studying pancreatic cancer intratumor heterogeneity, we aim to further characterize the nature of MIA PaCa-2 cells' phenotypic, genomic, and transcriptomic heterogeneity. MIA PaCa-2 single-cell clones were established through flow cytometry. For the phenotypic study, we quantified the cellular morphology, proliferation rate, migration potential, and drug sensitivity of the clones. The chromosome copy number and transcriptomic profiles were quantified using SNPa and RNA-seq, respectively. Four MIA PaCa-2 clones showed distinctive phenotypes, with differences in cellular morphology, proliferation rate, migration potential, and drug sensitivity. We also observed a degree of genomic variations between these clones in form of chromosome copy number alterations and single nucleotide variations, suggesting the genomic heterogeneity of the population, and the intrinsic genomic instability of MIA PaCa-2 cells. Lastly, transcriptomic analysis of the clones also revealed gene expression profile differences between the clones, including the uniquely regulated ITGAV, which dictates the morphology of MIA PaCa-2 clones. MIA PaCa-2 is comprised of cells with distinctive phenotypes, heterogeneous genomes, and differential transcriptomic profiles, suggesting its suitability as a model to study the underlying mechanisms behind pancreatic cancer heterogeneity.

Use of deep learning to evaluate tumor microenvironmental features for prediction of colon cancer recurrence.

Deep learning may detect biologically important signals embedded in tumor morphologic features that confer distinct prognoses. Tumor morphological features were quantified to enhance patient risk stratification within DNA mismatch repair (MMR) groups using deep learning. Using a quantitative segmentation algorithm (QuantCRC) that identifies 15 distinct morphological features, we analyzed 402 resected stage III colon carcinomas (191 d-MMR; 189 p-MMR) from participants in a phase III trial of FOLFOX-based adjuvant chemotherapy. Results were validated in an independent cohort (176 d-MMR; 1094 p-MMR). Association of morphological features with clinicopathologic variables, MMR, KRAS, BRAFV600E, and time-to-recurrence (TTR) was determined. Multivariable Cox proportional hazard models were developed to predict TTR. Tumor morphological features differed significantly by MMR status. Cancers with p-MMR had more immature desmoplastic stroma. Tumors with d-MMR had increased inflammatory stroma, epithelial tumor-infiltrating lymphocytes (TILs), high grade histology, mucin, and signet ring cells. Stromal subtype did not differ by BRAFV600E or KRAS status. In p-MMR tumors, multivariable analysis identified tumor-stroma ratio (TSR) as the strongest feature associated with TTR [HRadj 2.02; 95% CI,1.14-3.57; P=0.018; 3-year recurrence: 40.2% vs 20.4%; Q1 vs Q2-4]. Among d-MMR tumors, extent of inflammatory stroma [continuous HRadj 0.98; 95% CI,0.96-0.99; P=0.028; 3-year recurrence: 13.3% vs 33.4%, Q4 vs Q1] and N stage were the most robust prognostically. Association of TSR with TTR was independently validated. In conclusion, QuantCRC can quantify morphological differences within MMR groups in routine tumor sections to determine their relative contributions to patient prognosis, and may elucidate relevant pathophysiologic mechanisms driving prognosis.

A new cryptic species in Behria (Asparagaceae, Brodiaeoideae), from the Baja California peninsula, Mexico

Behria is a genus of petaloid geophytes endemic to the Cape Region of Baja California Sur, Mexico. It belongs to the Milla clade within the subfamily Brodiaeoideae of the Asparagaceae family. Currently, Behria tenuiflora is the only recognized species within this genus. In our methodological approach, we considered two distinct floral morphotypes: Group A consists of populations found at lowland elevations (10–150 m), while Group B comprises plants growing at mid to high elevations (400–2060 m). The aim of our study was to investigate whether there are discernible morphological differences and correlations with climate variables between Behria Group A and Group B. To address this, we measured nine quantitative characters for 94 plants from seven populations of Behria tenuiflora. Our findings revealed statistically significant differences (P < 0.05) in pedicel length, perianth length, perianth base diameter, and perianth aperture diameter of the analyzed Behria groups. Based on these results, we propose the recognition of Behria leonis as a new species. Additionally, we provide a morphological key for distinguishing Behria and Bessera genera, along with illustrations, a distribution map, and photographs.

Myers' divisions revisited: Contemporary evidence for distinct trait differences among global inland fishes

AbstractEighty years ago, George S. Myers classified inland fishes in three divisions (primary, secondary and peripheral) based on their salinity tolerance and eco‐evolutionary history. Although this classification has been followed by many fish studies, it has also received considerable criticism. Here, we aim to test for differences in salinity and thermal tolerance, species traits and distribution patterns among the three divisions using data for about 21,000 species. We found that primary fishes have much less salinity tolerance than secondary and peripheral species, with some secondary fishes displaying the highest tolerances (>100 ppt). We also provide, for the first time, evidence of significant phylogenetic signal of salinity tolerance, comparable in magnitude to conservative traits, and show that studied peripheral and secondary species have maintained or even developed salinity tolerance, in contrast to primary fishes. Although peripheral fishes are the most different, and despite the large variability observed within some families, primary and secondary species also show differences in morphology and life‐history traits. The distribution ranges and genetic diversity of primary and secondary fish divisions are similar and differ from peripheral species, suggesting that although there is evidence of oceanic dispersal of a few secondary fishes at evolutionary time scales, it is a rare contemporary phenomenon. Importantly, a few findings outlined in this study, namely, differences in salinity tolerance, rely on limited data. Thus, we urge for additional empirical research on the salinity tolerance of freshwater fish, which remains largely unexplored, to help clarify differences among and within clades.

SDPR expression in human trabecular meshwork and its potential role in racial disparities of glaucoma

In order to identify how differential gene expression in the trabecular meshwork (TM) contributes to racial disparities of caveolar protein expression, TM dysfunction and development of primary open angle glaucoma (POAG), RNA sequencing was performed to compare TM tissue obtained from White and Black POAG surgical (trabeculectomy) specimens. Healthy donor TM tissue from White and Black donors was analyzed by PCR, qPCR, immunohistochemistry staining, and Western blot to evaluate SDPR (serum deprivation protein response; Cavin 2) and CAV1/CAV2 (Caveolin 1/Caveolin 2). Standard transmission electron microscopy (TEM) and immunogold labeled studies were performed. RNA sequencing demonstrated reduced SDPR expression in TM from Black vs White POAG patients’ surgical specimens, with no significant expression differences in other caveolae-associated genes, confirmed by qPCR analysis. No racial differences in SDPR gene expression were noted in healthy donor tissue by PCR analysis, but there was greater expression as compared to specimens from patients with glaucoma. Analysis of SDPR protein expression confirmed specific expression in the TM regions, but not in adjacent tissues. TEM studies of TM specimens from healthy donors did not demonstrate any racial differences in caveolar morphology, but a significant reduction of caveolae with normal morphology and immuno-gold staining of SDPR were noted in glaucomatous TM as compared to TM from healthy donors. Linkage of SDPR expression levels in TM, POAG development, and caveolar ultrastructural morphology may provide the basis for a novel pathway of exploration of the pathologic mechanisms of glaucoma. Differential gene expression of SDPR in TM from Black vs White subjects with glaucoma may further our understanding of the important public health implications of the racial disparities of this blinding disease.

Molecular and SEM studies on Thaparocleidus vistulensis (Siwak, 1932) (Monopisthocotyla, Ancylodiscoididae)

Presenting new molecular and scanning electron microscope (SEM) features, this study gives additional data to the better knowledge of Thaparocleidus vistulensis (Siwak, 1932) (Monopisthocotyla, Ancylodiscoididae), a parasite of the European catfish Silurus glanis Linnaeus, 1758 (Siluriformes, Siluridae) cultured in a commercial fish farm in Hungary. In addition, notes on the early development of sclerotized anchors are also provided. The main morphological difference of T. vistulensis compared to other congeneric species is associated with the male copulatory organ, which exhibits 5–7 loops in the middle of the penis length and a long open V-shaped sclerotized accessory piece, dividing terminally into two parts, securing the terminal part of the penis tube. The present study provides for the first time molecular characterization data based on the 2694 bp long nucleotide sequence of rDNA (ITS1, 5.8S, ITS2, and flanked with partial 18S and partial 28S) submitted in GenBank with the accession number OR916383. A phylogenetic tree based on ITS1 sequences supports a well-defined clade including T. vistulensis, forming a sister group with T. siluri, a species-specific monopisthocotylan parasite to S. glanis. The morphological characterization of T. vistulensis, especially for the male copulatory organ, together with the molecular data in the present study, extends knowledge about this monopisthocotylan species and provides new information for future phylogeny studies.

Clarification of taxonomic status of Pseudochorthippus geminus (Mistshenko, 1951) (Orthoptera: Acrididae: Gomphocerinae) based on male calling song analysis

Pseudochorthippus geminus is redescribed and illustrated based on specimens from southern Kazakhstan and northern Kyrgyzstan. Oscillograms of the male calling songs of P. geminus from these localities and of P. parallelus from southern Kazakhstan are given. Comparative analysis of the song temporal patterns of P. geminus and P. parallelus clearly indicates that they represent separate biological species, but the morphological differences between them are indistinct and do not always provide reliable characters for species diagnostics.

Perspective on High-Stability Single-Crystal Li-Rich Cathode Materials for Li-Ion Batteries.

Benefiting from anionic and cationic redox reactions, Li-rich materials have been regarded as next-generation cathodes to overcome the bottleneck of energy density. However, they always suffer from cracking of polycrystalline (PC) secondary particles and lattice oxygen release, resulting in severe structural deterioration and capacity decay upon cycling. Single-crystal (SC) design has been proven as an effective strategy to relieve these issues in traditional Li-rich cathodes with PC morphology. Herein, we first reviewed the main synthesis routes of SC Li-rich materials including solid-state reaction, molten salt-assisted, and hydrothermal/solvothermal methods, in which the differences in grain morphology, electrochemical behaviors, and other properties induced by various routes were analyzed and discussed. Furthermore, the distinct characteristics were compared between SC and PC cathodes from the aspects of irreversible capacity, structural stability, capacity/voltage degradation, and gas release. Besides, recent advances in layered SC Li-rich oxide cathodes were summarized in detail, where the unique structural designs and modification strategies could greatly promote their structural/electrochemical stability. At last, challenges and perspectives for the emerging SC Li-rich cathodes were proposed, which provided an exceptional opportunity to achieve high-energy-density and high-stability Li-ion/metal batteries.

A new Actinella species (Eunotiaceae, Bacillariophyta) from the Yangambi Biosphere Reserve, Democratic Republic of the Congo

Background and aims – Actinella species from Central Africa are only rarely reported. The acid waters from many stream and small rivers in the Congo Basin form a potential environment for species of this genus. We studied several samples from the region of Yangambi to confirm whether species belonging to this genus are present. Material and methods – Samples for diatom investigation were collected in several streams and small rivers (Moni, Ngima, and Libongo), in the tropical rainforest in the Yangambi Biosphere Reserve, Tshopo Province, Democratic Republic of the Congo. The samples were prepared to obtain permanent microscope slides for light microscopy studies using standard methods and cleaned material for scanning electron microscopy. Key results – A novel Actinella was observed in the studied samples. The taxon was compared to other species such as A. disjuncta, A. lange-bertalotii, A. modesta, A. pereunotioides, and A. pseudohantzschia, although the new species morphologically resembles most A. eunotioides, a species discovered in the Amazon basin in Brazil, and A. eunotioides var. minor, described in 1966 from the Central African Republic. The taxon observed in our material differs from A. eunotioides mainly in the valve dimensions, being much smaller, and the higher density of the marginal spines. Stria density also tends to be coarser. The valve length of A. eunotioides var. minor, on the other hand, corresponds with the smallest valves of our taxon but the valves are narrower, with a higher stria density. The ventral margin is slightly convex, while in the new taxon it is slightly concave. Moreover, in the original description of A. eunotioides var. minor, the absence of spines is mentioned, while they are present on the valves in the materials we investigated. Based on the observed morphological differences, we consider the taxon recorded in the streams and small rivers in the Yangambi Biosphere Reserve distinct from A. eunotioides and its var. minor and subsequently, we describe Actinella kufferathiana as a species new to science.

Structure and morphology of chars and activated carbons obtained from thermal treatment of coal and biomass origin materials, including their wastes: Results from the ICCP Microscopy of Carbon Materials Working Group

This paper describes the evaluation of petrographic textures in char and activated carbon derived from coal, coal by-products and biomass, formed during carbonization and activation processes. This work represents the results of interlaboratory exercises from 2016 to 2022 of the Microscopy of Carbon Materials Working Group in Commission III of the International Committee for Coal and Organic Petrology. The interlaboratory exercises were run on photomicrograph samples. For textural characterization of carbon materials, the existing American Society for Testing and Materials (ASTM) classification system for metallurgical coke was applied. Morphological differences were evaluated in 29 carbon material types, including 22 char samples, and 7 activated carbon (AC) samples obtained experimentally using conventional direct/indirect and microwave heating technologies. This approach gives an extended view on the identification of microporous carbons, and how a certain heat treatment develops a certain optical texture and structure in a raw material. The requested evaluation of carbon materials was related to their porosity, origin, extent, and characteristics, which are particular to each carbon material type. Because carbon matrices can form a wide range of optical textures during heat treatment it is important to demonstrate which carbon occurrences will have a crucial role in industrial applications dominated by adsorption phenomena.The interlaboratory exercises included 17 participants from 14 laboratories. Four sets of digital black and white and colour photomicrographs were distributed, which in total comprised 184 fields of different types of carbon material. The results were evaluated based on four levels: (i) optical texture (isotropic/anisotropic), (ii) optical type and size (punctiform, mosaic, fiber, ribbon, domain), iii) morphology (porous, non-porous/massive), and (iv) particle origin (precursor type).The statistical method applied to evaluate the results was based on “raw agreement indices”. Comparative analyses of the average values of the level of overall agreement showed homogeneity in the results, the mean value was 89%, with a minimum value of 87% and a maximum value of 91% for those who participated in at least three out of four exercises.

Generation of Mammalian Astrocyte Functional Heterogeneity.

Mammalian astrocytes have regional roles within the brain parenchyma. Indeed, the notion that astrocytes are molecularly heterogeneous could help explain how the central nervous system (CNS) retains embryonic positional information through development into specialized regions into adulthood. A growing body of evidence supports the concept of morphological and molecular differences between astrocytes in different brain regions, which might relate to their derivation from regionally patterned radial glia and/or local neuron inductive cues. Here, we review evidence for regionally encoded functions of astrocytes to provide an integrated concept on lineage origins and heterogeneity to understand regional brain organization, as well as emerging technologies to identify and further investigate novel roles for astrocytes.

Biometric analysis of the calcareous nannofossil group reticulofenestrids from the Oligocene to the Miocene

The calcareous nannofossil genus Reticulofenestra and its related taxa are called “reticulofenestrids,” and they were one of the major nannofossil groups during the Cenozoic. The reticulofenestrid specimens are composed of two shields, proximal and distal, which are circular or subcircular in shape and consist of tiny calcite plates. Cyclic changes in the size and shape of reticulofenestrid coccoliths have been used to characterize their evolution. The major taxonomic turnover in this group was related to environmental changes during the Cenozoic. From the Oligocene to the Miocene, there were several different types of reticulofenestrids. The primary taxon of reticulofenestrids disappeared during the Oligocene-Miocene boundary, and elliptical species emerged during the early Miocene. However, it is uncertain exactly when and how the change in reticulofenestrids occurred. To understand the evolutionary trends of reticulofenestrids, we conducted biometric analyses from the Oligocene to the Miocene. Detailed observation and measurement of reticulofenestrid coccoliths under a scanning electron microscope revealed a significant size reduction in the group near the Oligocene–Miocene, which corresponds to a period of rapid global cooling. Furthermore, regarding the reticulofenestrid taxa in this study, central structures characterize the Oligocene genus Dictyococcites, and the long axis length of the coccolith outline and central areas can be effective characteristics for distinguishing between theMiocene Cyclicargolithus and Reticulofenestra. These results suggest that morphological differences of reticulofenestrids are expressed not only in the shape and size of the coccolith but also in the size and shape of its central area.

Chewing asymmetry in dogs: Exploring the importance of the fossa masseterica and first molar teeth morphology.

Dogs are animals with strong bite force. This strong bite mechanism has led to significant changes in the skeletal system such as fossa masseterica. It can be thought that one side is used more than the other side in chewing and is related to the preference of using the same side's hand, eye and foot. In the study, directional asymmetry and fluctuating asymmetry, which occurs as a result of chewing asymmetry, were examined on the first molar teeth and the fossa masseterica in 85 dog mandibles including a wide diversity of morphotypes. The association of high PC1 values for directional asymmetry with a pronounced cranial index, as evident in breeds like Pekingese, Pomeranian and Bulldog, indicates a potential evolutionary or selective breeding trend favouring brachycephaly. On the contrary, guardian breeds like the German shepherd and Bernese mountain dog, which typically require strong jaws for their roles, showcased reduced PC1 values, which might be related to their functional morphology. Similarly, the PCA results for the first molar teeth shape variations also highlighted the influence of cranial shape, with boxer dogs displaying notably higher PC1 values. The fluctuating asymmetrical distributions provided valuable insights into individualistic variations. Interestingly, no specific breed distribution trend was observed for these asymmetries, indicating a more individual-based variation rather than breed-based. It is essential to note that while these results provide valuable insights, further studies are required to understand the underlying causes better. Factors like genetic variations, developmental processes, dietary habits and external environmental factors could play pivotal roles in these observed morphological differences.

CLDN1 knock out keratinocytes as a model to investigate multiple skin disorders.

The transmembrane protein claudin-1 is critical for formation of the epidermal barrier structure called tight junctions (TJ) and has been shown to be important in multiple disease states. These include neonatal ichthyosis and sclerosing cholangitis syndrome, atopic dermatitisand various viral infections. To develop a model to investigate the role of claudin-1 in different disease settings, we used CRISPR/Cas9 to generate human immortalized keratinocyte (KC) lines lacking claudin-1 (CLDN1 KO). We then determined whether loss of claudin-1 expression affects epidermal barrier formation/function and KC differentiation/stratification. The absence of claudin-1 resulted in significantly reduced barrier function in both monolayer and organotypic cultures. CLDN1 KO cells demonstrated decreases in gene transcripts encoding the barrier protein filaggrin and the differentiation marker cytokeratin-10. Marked morphological differences were also observed in CLDN1 KO organotypic cultures including diminished stratification and reduced formation of the stratum granulosum. We also detected increased proliferative KC in the basale layer of CLDN1 KO organotypic cultures. These results further support the role of claudin-1 in epidermal barrier and suggest an additional role of this protein in appropriate stratification of the epidermis.

Allometric relationships and trade-offs in 11 common Mediterranean-climate grasses.

Biomass allocation in plants is the foundation for understanding dynamics in ecosystem carbon balance, species competition, and plant-environment interactions. However, existing work on plant allometry has mainly focused on trees, with fewer studies having developed allometric equations for grasses. Grasses with different life histories can vary in their carbon investment by prioritizing the growth of specific organs to survive, outcompete co-occurring plants, and ensure population persistence. Further, because grasses are important fuels for wildfire, the lack of grass allocation data adds uncertainty to process-based models that relate plant physiology to wildfire dynamics. To fill this gap, we conducted a greenhouse experiment with 11 common California grasses varying in photosynthetic pathway and growth form. We measured plant sizes and harvested above- and belowground biomass throughout the life cycle of annual species, while for the establishment stage of perennial grasses to quantify allometric relationships for leaf, stem, and root biomass, as well as plant height and canopy area. We used basal diameter as a reference measure of plant size. Overall, basal diameter is the best predictor for leaf and stem biomass, height, and canopy area. Including height as another predictor can improve model accuracy in predicting leaf and stem biomass and canopy area. Fine root biomass is a function of leaf biomass alone. Species vary in their allometric relationships, with most variation occurring for plant height, canopy area, and stem biomass. We further explored potential trade-offs in biomass allocation across species between leaf and fine root, leaf and stem, and allocation to reproduction. Consistent with our expectation, we found that fast-growing plants allocated a greater fraction to reproduction. Additionally, plant height and specific leaf area negatively influenced the leaf-to-stem ratio. However, contrary to our hypothesis, there were no differences in root-to-leaf ratio between perennial and annual or C4 and C3 plants. Our study provides species-specific and functional-type-specific allometry equations for both above- and belowground organs of 11 common California grass species, enabling nondestructive biomass assessment in California grasslands. These allometric relationships and trade-offs in carbon allocation across species can improve ecosystem model predictions of grassland species interactions and environmental responses through differences in morphology.

The long‐beaked common dolphin of the eastern Pacific Ocean: Taxonomic status and redescription of Delphinus bairdii

AbstractNeritic, long‐beaked common dolphins have been described as species distinct from the more oceanic and globally distributed short‐beaked species, Delphinus delphis, although recent molecular studies have challenged this view. In the eastern North Pacific (ENP), the taxonomic status of the long‐beaked (bairdii) form has been controversial since its original description in 1873, and has vacillated between species, subspecies, and geographic forms several times. It is currently provisionally viewed as a subspecies of Delphinus delphis, D. d. bairdii. To clarify this situation, we reviewed the literature and conducted additional analyses using both newly obtained genetic and cranial morphometric data sets. The results indicate that there are diagnostic differences in skull morphology and coloration between the eastern Pacific long‐and short‐beaked forms, and near‐perfect diagnosability in mitochondrial DNA. These differences, along with indications of ecological distinctions, including important differences in life history parameters and reproductive timing, indicate that these forms are well on their way down separate evolutionary pathways. As such, we consider them to be distinct species in the eastern Pacific. The long‐beaked species is referable to Delphinus bairdii Dall, 1873, and is redescribed as such herein.

Tailoring MOF-5 Photocatalysts: Low-Temperature Synthesis and Solvent Variations for Enhanced Performance in Dye Degradation

Metal-organic frameworks (MOFs) are emerging as pivotal porous crystalline materials with diverse applications. Typically, MOFs are synthesized using solvothermal techniques at high temperatures and pressures. In this study, a novel approach was employed to synthesize zinc-based MOFs, specifically MOF-5, at low temperatures (up to 50 °C) via chemical mixing at standard pressures. Varying the temperature and solvents, N-methyl-2-pyrrolidone (NMP) and N,N-dimethylformamide (DMF), in the chemical mixing process, the highest yield of the material was observed with DMF at 50 °C (M1). Two additional samples, M2 and M3, are synthesized at room temperature using DMF and NMP, respectively. Despite similarities in XRD, Raman, and FTIR analyses confirming successful MOF-5 formation, noticeable differences in sample morphology arise due to distinct synthesis conditions, particularly solvent and temperature variations. The MOF-5 samples exhibit UV absorption with varying band gaps. Notably, when employed as photocatalysts for organic dye (methylene blue) degradation, M2 outperforms others, achieving an impressive 85% degradation under simulated solar light irradiation. This work underscores the significance of tuning MOF photocatalyst properties through tailored synthesis routes, recognizing the profound impact of morphology and elemental composition on enhancing photocatalytic dye degradation performance. Copyright © 2024 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 

Review of the Newly Established amictus-Subgroup of the Genus Leptocoris (Hemiptera: Heteroptera: Rhopalidae), with the Description of a New Species from the Arabian Peninsula

Leptocoris arabicus new species (Hemiptera: Heteroptera: Rhopalidae: Serinethinae) is described based on 55 specimens of both sexes collected in various localities of southern Oman and southeastern Yemen; a hypothesis is proposed as to its host plant. The new species is close to Leptocoris amictus Germar, 1838 and to Leptocoris ruber Göllner-Scheiding, 1980, new status, due to the presence of a produced horned process along the posterior ventral margin of the genital capsule. It is distinguished from both by differences in colour pattern and morphology. An informal L. amictus species-subgroup is proposed to accommodate these three species within the Leptocoris hexophthalmus species-group sensu Göllner-Scheiding (1980). The following new faunistic records are also provided: L. amictus from Ethiopia, Mozambique and Zambia; L. ruber from Central African Republic. The occurrence of L. chevreuxi (Noualhier, 1893) in Oman is confirmed. The list of all available species-group names assigned to Leptocoris Hahn, 1833 (gender masculine) and their synonyms is compiled and the gender agreement is corrected in the species names when appropriate. The nomenclatural problem concerning Leptocoris living on Marshall Islands discovered by Kerzhner (2003) is discussed and the following corrections are provided: Leptocoris rufus rufus Hahn, 1833, new status = Leptocoris lariversi Usinger, 1952, new synonymy, and Leptocoris rufus isolatus (Distant, 1914) new status.  

Molecular systematics of the subgenus Gephyromantis (Phylacomantis) with description of a new subspecies

The mantellid subgenus Phylacomantis (genus Gephyromantis) currently contains four species of frogs distributed in the South (G. corvus, G. kintana), West (G. atsingy), North East, North, and Sambirano regions (G. pseudoasper) in Madagascar. We assess the molecular systematics of these amphibians based on extended sampling and analysis of multiple nuclear-encoded and mitochondrial genes. We confirm the delimitation of the four known species, which form monophyletic groups in a mitochondrial tree and separate phylogroups without haplotype sharing in haplotype networks of four nuclear markers. Newly included samples of G. pseudoasper from the North and North East regions confirm a comparatively low genetic variation of this species across its range, with pairwise genetic distance in the 16S gene not exceeding 1.4%. On the contrary, newly collected specimens from three sites in the North East and North West of the island strongly differed from all other Phylacomantis, with genetic distances exceeding 4.8% for the16S gene. Mitochondrial and nuclear markers strongly suggest them to be sister to G. corvus from the South. Due to haplotype sharing in two nuclear genes, absence of detectable morphological differences, and lack of data on bioacoustic differentiation, we describe these populations as a new subspecies, G. corvus bakilana ssp. nov., emphasizing that this taxon may be elevated to species status in the future pending new data. This biogeographic pattern, with apparently disjunct sister lineages in the South vs. North West of Madagascar, is rare among Malagasy anurans and calls for increased exploration of the remaining humid forest fragments in the North West and West of the island.

A shared pattern of midfacial bone modelling in hominids suggests deep evolutionary roots for human facial morphogenesis.

Midfacial morphology varies between hominoids, in particular between great apes and humans for which the face is small and retracted. The underlying developmental processes for these morphological differences are still largely unknown. Here, we investigate the cellular mechanism of maxillary development (bone modelling, BM), and how potential changes in this process may have shaped facial evolution. We analysed cross-sectional developmental series of gibbons, orangutans, gorillas, chimpanzees and present-day humans (n = 183). Individuals were organized into five age groups according to their dental development. To visualize each species's BM pattern and corresponding morphology during ontogeny, maps based on microscopic data were mapped onto species-specific age group average shapes obtained using geometric morphometrics. The amount of bone resorption was quantified and compared between species. Great apes share a highly similar BM pattern, whereas gibbons have a distinctive resorption pattern. This suggests a change in cellular activity on the hominid branch. Humans possess most of the great ape pattern, but bone resorption is high in the canine area from birth on, suggesting a key role of canine reduction in facial evolution. We also observed that humans have high levels of bone resorption during childhood, a feature not shared with other apes.