Rare Trait Research Articles

Taxonomic revision of the genus Sarcosphaera (Ascomycota: Pezizales) in Europe and North America revealed unexpected diversity

Sarcosphaera (Ascomycota: Pezizales) is a genus of rare spring fungi, currently encompassing a single species, S. coronaria, which is red-listed in many European countries. The genus is characterized by large bright-colored fruit-bodies and high arsenic content. This study investigates the genetic diversity across Europe and North America. Using integrated molecular techniques, including ITS and 28S rDNA sequencing, we aimed to resolve the taxonomic ambiguities and assess their arsenic hyperaccumulation capabilities, a rare trait among fungi. We identified the presence of two species in the Western Palearctic (S. coronaria, S. crassa) and at least 12 additional lineages in North America, indicating a more complex taxonomic structure than previously recognized. To consolidate the taxonomy and nomenclature of these fungi, we selected reference specimens for S. coronaria and S. crassa and discussed their morphological and ecological differences. Two genera, Caulocarpa (C. montana) and Hydnotryopsis (H. setchellii), a genus comprising hypogeous fungi, are newly placed in the genus Sarcosphaera. Sarcosphaera is thus another genus where the rapid evolution of hypogeous forms from their above-ground ancestors took place. Furthermore, two new Sarcosphaera species, S. columbiana and S. pacifica, are described from the Pacific Northwest. Investigation of arsenic content of Sarcosphaera species revealed that arsenic mass fractions in ascocarps vary significantly between species and even within species across different geographical locations. Our findings have important implications for the taxonomy and conservation of the S. coronaria species complex and also point to future directions for further research in the taxonomy, geomycology, and toxicology of this group of fungi.

Convergent reductive evolution in bee-associated lactic acid bacteria.

Distantly related organisms may evolve similar traits when exposed to similar environments or engaging in certain lifestyles. Several members of the Lactobacillaceae [lactic acid bacteria (LAB)] family are frequently isolated from the floral niche, mostly from bees and flowers. In some floral LAB species (henceforth referred to as bee-associated LAB), distinctive genomic (e.g., genome reduction) and phenotypic (e.g., preference for fructose over glucose or fructophily) features were recently documented. These features are found across distantly related species, raising the hypothesis that specific genomic and phenotypic traits evolved convergently during adaptation to the floral environment. To test this hypothesis, we examined representative genomes of 369 species of bee-associated and non-bee-associated LAB. Phylogenomic analysis unveiled seven independent ecological shifts toward the bee environment in LAB. In these species, we observed significant reductions of genome size, gene repertoire, and GC content. Using machine leaning, we could distinguish bee-associated from non-bee-associated species with 94% accuracy, based on the absence of genes involved in metabolism, osmotic stress, or DNA repair. Moreover, we found that the most important genes for the machine learning classifier were seemingly lost, independently, in multiple bee-associated lineages. One of these genes, acetaldehyde-alcohol dehydrogenase (adhE), encodes a bifunctional aldehyde-alcohol dehydrogenase which has been associated with the evolution of fructophily, a rare phenotypic trait that is pervasive across bee-associated LAB species. These results suggest that the independent evolution of distinctive phenotypes in bee-associated LAB has been largely driven by independent losses of the same sets of genes.IMPORTANCESeveral LAB species are intimately associated with bees and exhibit unique biochemical properties with potential for food applications and honeybee health. Using a machine learning-based approach, our study shows that adaptation of LAB to the bee environment was accompanied by a distinctive genomic trajectory deeply shaped by gene loss. Several of these gene losses occurred independently in distantly related species and are linked to some of their unique biotechnologically relevant traits, such as the preference for fructose over glucose (fructophily). This study underscores the potential of machine learning in identifying fingerprints of adaptation and detecting instances of convergent evolution. Furthermore, it sheds light onto the genomic and phenotypic particularities of bee-associated bacteria, thereby deepening the understanding of their positive impact on honeybee health.

Alternative splicing and deletion in S-RNase confer stylar-part self-compatibility in the apple cultivar 'Vered'.

Although self-incompatibility in apples (Malus × domestica Borkh.) is regulated by a single S-locus with multiple S-haplotypes that comprise pistil S (S-RNase) and pollen S genes, it is not desirable in commercial orchards because it requires cross-pollination to achieve stable fruit production. Therefore, it is important to identify and characterize self-compatible apple cultivars. However, little is known about self-compatibility(SC) and its underlying molecular mechanisms in apples. In this study, we discovered that 'Vered', an early maturing and low chilling-requiring apple cultivar, exhibits stable SC, which was evaluated via self-pollination tests. The S-genotype of 'Vered' was designated as S24S39sm. Results of genetic analysis of selfed progeny of 'Vered' revealed that SC is associated with the S39sm-haplotype, and molecular analyses indicated that it is caused by alternative splicing and a 205-bp deletion in S39sm-RNase. These events induce frameshifts and ultimately produce the defective S39sm-RNase isoforms that lack their C-terminal half. These results enabled us to develop a 117-bp DNA marker that can be used to assist in the selection of self-compatible apples with the dysfunctional S39sm-RNase. Thus, analysis of 'Vered' provided insights into the molecular mechanism of the very rare trait of natural stylar-part SC. Moreover, 'Vered' is a valuable genetic resource for breeding cultivars with SC and/or low chilling requirement in apple. Our findings contribute to a better understanding of self-compatible molecular mechanisms in apple and provide for the accelerated breeding of self-compatible apple cultivars.

Familial Renal Glucosuria and Potential Pharmacogenetic Impact on SGLT2 Inhibitors.

Renal glucosuria is a rare inheritable trait caused by loss-of-function variants in the gene that encodes SGLT2 (i.e., SLC5A2). The genetics of renal glucosuria is poorly understood and even less is known on how loss-of-function variants in SLC5A2 may affect response to SGLT2 inhibitors, a new class of medication gaining popularity to treat diabetes by artificially inducing glucosuria. We used two biobanks that link genomic with electronic health record data to study the genetics of renal glucosuria. This included 245,394 participants enrolled in the All of Us (AoU) Research Program and 11,011 enrolled in Marshfield Clinic's Personalized Research Project (PMRP). Association studies in AoU and PMRP identified 10 variants that reached an experiment-wise Bonferroni threshold in either cohort, nine were novel. PMRP was further used as a recruitment source for a prospective SGLT2 pharmacogenetic trial. During a glucose tolerance test, the trial measured urine glucose concentrations in 15 SLC5A2 variant-positive individuals and 15 matched wild types with and without an SGLT2 inhibitor. This trial demonstrated that carriers of SLC5A2 risk variants may be more sensitive to SGLT2 inhibitors compared to wild types (P=0.075). Based on population data, 2% of an ethnically diverse population carry rare variants in SLC5A2 and are at risk for renal glucosuria. As a result, 2% of individuals being treated with SGLT2 inhibitors may respond differently to this new class of medication compared to the general population suggesting a larger investigation into SLC5A2 variants and SGLT2 inhibitors is needed.

Ceratozamia guatemalensis (Zamiaceae): A new cycad species from Mesoamerica

Ceratozamia guatemalensis, a new cycad species from the Sierra de los Cuchumatanes, Huehuetenango, Guatemala, is described and compared with the geographically proximal congeners C. vovidesii and C. matudae, with which C. guatemalensis has been historically confused based on their pendulous seed cones, a rare trait in the genus. Nonetheless, a recent phylogenetic study suggests that C. guatemalensis and C. vovidesii are sister species, while C. matudae belongs to distant clade. The new taxon is easily distinguishable from both C. vovidesii and C. matudae by qualitative and quantitative traits based on vegetative and reproductive structures. Remarkably, C. guatemalensis is characterized by having significant morphometric differences from the other two species, such as the wider median leaflets and wider leaflet articulations, and qualitative traits such as the seed cones of green color. The description of C. guatemalensis represents the recognition of the first endemic Ceratozamia species from Guatemala. It should be considered Critically Endangered (CR) due to limited populations and the ongoing destruction of its habitat.

Global Avian Functional Diversity Depends on the World's Most Widespread and Distinct Birds.

The relationship between global trait distinctiveness and geographic range size is an emerging pattern of interest in macroecology. Early observations suggested that the relationship was positive, implying that globally widespread species hold the rarest combinations of traits. Here, we formally describe and test the relationship in the world's birds and consider its implications for global functional diversity and redundancy. We demonstrate that the relationship is best described as triangular with a positive upper boundary, with its linear model significance lost when including phylogenetic effects. The triangular relationship is formed by groups of phylogenetically related widespread species with moderate and high trait distinctiveness. Decomposing the relationship further using quantile regression highlights the unique traits of these widespread birds. Overall, the triangular relationship emphasises that while not all widespread species have rare trait combinations, those that do should not be overlooked in conservation efforts, regardless of their current threat status.

Clinical and molecular characterization of patients with YWHAG-related epilepsy.

YWHAG variant alleles have been associated with a rare disease trait whose clinical synopsis includes an early onset epileptic encephalopathy with predominantly myoclonic seizures, developmental delay/intellectual disability, and facial dysmorphisms. Through description of a large cohort, which doubles the number of reported patients, we further delineate the spectrum of YWHAG-related epilepsy. We included in this study 24 patients, 21 new and three previously described, with pathogenic/likely pathogenic variants in YWHAG. We extended the analysis of clinical, electroencephalographic, brain magnetic resonance imaging, and molecular genetic information to 24 previously published patients. The phenotypic spectrum of YWHAG-related disorders ranges from mild developmental delay to developmental and epileptic encephalopathy (DEE). Epilepsy onset is in the first 2 years of life. Seizure freedom can be achieved in half of the patients (13/24, 54%). Intellectual disability (23/24, 96%), behavioral disorders (18/24, 75%), neurological signs (13/24, 54%), and dysmorphisms (6/24, 25%) are common. A genotype-phenotype correlation emerged, as DEE is more represented in patients with missense variants located in the ligand-binding domain than in those with truncating or missense variants in other domains (90% vs. 19%, p < .001). This study suggests that pathogenic YWHAG variants cause a wide range of clinical presentations with variable severity, ranging from mild developmental delay to DEE. In this allelic series, a genotype-phenotype correlation begins to emerge, potentially providing prognostic information for clinical management and genetic counseling.

Study on changing disciplinarian of beak colors in ducks and the regulation network based on transcriptome sequencing

Beak color in ducks is a primary characteristic of local breeds and genetic resources. Among them, black beaks, a rare packaging trait of high-quality duck products, have attracted much attention. In this study, Runzhou White Created ducks (black beak) and white-feathered Putian black ducks (yellow beak) were used to construct the F2 generation resource population to study the changing discipline of beak color combined with the beak color statistics of gray-beaked ducklings of Runzhou White Created ducks. Subsequently, transcriptome sequencing was performed to identify genetic markers related to beak color. To explore the rules of beak color change and its regulatory network, trends, and trend analysis and weighted gene co-expression network analysis（WGCNA）were performed. The screening results were verified by real-time quantitative polymerase chain reaction. A large difference was observed between the beak colors of birds from the F1 generation at 0 and 42 d of age. The F2 generation results show that nearly half of the black-beaked ducklings become green-beaked; the proportion of black spots for gray- and patterned-beaked ducklings increases with age, with most becoming green-beaked. Moreover, the beak color darkened from the first day, and the gray color value decreased significantly from the second day. Transcriptome sequencing indicated that TYR was differentially expressed between black and yellow beaks at 4 to 6 wk of age, and trend and WGCNA analyses showed that EDNRB signaling pathway genes and MITF were highly expressed in the first week, and TYR, TYRP1, and DCT were highly expressed at 4 to 6 wk of age. Therefore, there is melanin synthesis and deposition after hatching for gray- and patterned-beaked ducklings, while the yellow pigment might be deposited in the epidermis of beaks for black-beaked ducklings. The EDNRB signaling pathway is probably involved in early melanosome maturation and melanin formation in duck beaks, and genes such as TYR can maintain the black-beak phenotype.

Biallelic missense variants in COG3 cause a congenital disorder of glycosylation with impairment of retrograde vesicular trafficking.

Biallelic variants in genes for seven out of eight subunits of the conserved oligomeric Golgi complex (COG) are known to cause recessive congenital disorders of glycosylation (CDG) with variable clinical manifestations. COG3 encodes a constituent subunit of the COG complex that has not been associated with disease traitsin humans. Herein, we report two COG3 homozygous missense variants in four individuals from two unrelated consanguineous families that co-segregated with COG3-CDG presentations. Clinical phenotypes of affected individuals include global developmental delay, severe intellectual disability, microcephaly, epilepsy, facial dysmorphism, and variable neurological findings. Biochemical analysis of serum transferrin from one family showed the loss of a single sialic acid. Western blotting on patient-derived fibroblasts revealed reduced COG3 and COG4. Further experiments showed delayed retrograde vesicular recycling in patient cells. This report adds to the knowledge of the COG-CDG network by providing collective evidence for a COG3-CDG rare disease trait and implicating a likely pathology of the disorder as the perturbation of Golgi trafficking.

Talon cusp expression in Cayo Santiago rhesus macaques (Macaca mulatta).

This brief communication documents the prevalence of maxillary central incisor talon cusps in Cayo Santiago rhesus monkeys (Macaca mulatta) and assesses whether talon cusp presence occurs at equivalent frequencies across matrilines. The data on cusp presence vs. absence were analyzed by logistic regression in 170 monkeys (82 females, 78 males) from seven different matrilines. Sample sizes per matriline ranged from 10 to 42. Observations of talon cusps were blind with respect to matriline and sex. Talon cusps were present in 9.4% of the sample. By matriline, cusp frequencies ranged from 0%-Matrilines 073 and 106%-to 19.1% in Matriline 076. The frequency of the talon cusp in Matriline 076 was significantly greater than the frequency of the cusp in the remainder of the sample. There was no statistically significant difference in the frequency of the talon cusp by sex. This study suggests that the talon cusp in rhesus monkeys, as in humans and baboons, is a rare trait. Elevated prevalence of the talon cusp in Matriline 076 suggests the possibility of a genetic influence on talon cusp expression.

Anatomical observation and transcriptome analysis of branch-twisted mutations in Chinese jujube

BackgroundPlant organs grow in a certain direction and organ twisted growth, a rare and distinctive trait, is associated with internal structure changes and special genes. The twisted branch mutant of Chinese jujube jujube, an important fruit tree native to China and introduced to nearly 50 countries, provides new typical materials for exploration of plant twisted growth.ResultsIn this study, the cytological characteristics and related genes of twisted branches in Chinese jujube were revealed by microscopy observation and transcriptome analysis. The unique coexistence of primary and secondary structures appeared in the twisted parts of branches, and special structures such as collateral bundle, cortical bundles, and internal phloem were formed. Ninety differentially expressed genes of ‘Dongzao’ and its twisted mutant were observed, in which ZjTBL43, ZjFLA11, ZjFLA12 and ZjIQD1 were selected as candidate genes. ZjTBL43 was homologous to AtTBL43 in Arabidopsis, which was involved in the synthesis and deposition of cellular secondary wall cellulose. The attbl43 mutant showed significant inflorescence stem bending growth. The transgenic lines of attbl43 with overexpression of ZjTBL43 were phenotypically normal.The branch twisted growth may be caused by mutations in ZjTBL43 in Chinese jujube. AtIQD10, AtFLA11 and AtFLA12 were homologous to ZjIQD1, ZjFLA11 and ZjFLA12, respectively. However, the phenotype of their function defect mutants was normal.ConclusionIn summary, these findings will provide new insights into the plant organ twisted growth and a reference for investigation of controlling mechanisms of plant growth direction.

Metabolite Diversity in Pulp Segments, Peel, Leaves, and Bark of a Red-Fleshed ‘Baya Marisa’ Apple Cultivar

This study investigated the composition of sugars, organic acids, individual and total phenolic compounds in the pulp, peel, leaves, and bark of a red-fleshed ‘Baya Marisa’ apple cultivar. As the fruit is known for its red pulp color, the study focused on comparing the profiles of primary and selected secondary metabolites in three sections along the equatorial fruit plane. The analyses were carried out using HPLC–MS system, and compositional differences were compared among fruit segments. Inner fruit segments accumulated higher levels of sorbitol and the sum of sugars and lower levels of citric acid. However, no differences in the sum of organic acids could be determined among segments. The phenolic composition differed among pulp (hydroxycinnamic acids &gt; dihydrochalcones ≈ anthocyanins ≈ flavanols &gt; flavonols), peel (flavanols &gt; anthocyanins &gt; dihydrochalcones &gt; flavonols &gt; hydroxycinnamic acids), leaves (flavonols &gt; dihydrochalcones &gt; hydroxycinnamic acids &gt; anthocyanins), and bark (dihydrochalcones &gt; flavonols &gt; flavanols &gt; anthocyanins &gt; hydroxycinnamic acids). The greatest phenolic diversity was detected in bark (25), followed by leaves (18), peel (17) and finally, pulp (11). Three anthocyanins (cyanidin-3-O-galactoside &gt; cyanidin-3-O-arabinoside &gt; peonidin-3-O-galactoside) were determined in all ‘Baya Marisa’ tissues with their content highest in the peel. The innermost sections of the fruit were characterized by higher levels of dihydrochalcones and lower levels of most flavanols, flavonols and anthocyanins. These were predominant in the apple pulp nearest to the peel, with cyanidin-3-O-galactoside being the prevalent representative. Accumulation of anthocyanins in pulp is a rare trait in apples, and therefore, the distinct distribution and diversity of metabolites in this cultivar highlights its potential for high-nutrient products such as juices, apple chips or purees.

Sequential adaptive strategies for sampling rare clustered populations

A new class of sampling strategies is proposed that can be applied to population-based surveys targeting a rare trait that is unevenly spread over an area of interest. Our proposal is characterised by the ability to tailor the data collection to specific features and challenges of the survey at hand. It is based on integrating an adaptive component into a sequential selection, which aims both to intensify the detection of positive cases, upon exploiting the spatial clustering, and to provide a flexible framework to manage logistics and budget constraints. A class of estimators is also proposed to account for the selection bias, that are proved unbiased for the population mean (prevalence) as well as consistent and asymptotically Normal distributed. Unbiased variance estimation is also provided. A ready-to-implement weighting system is developed for estimation purposes. Two special strategies included in the proposed class are presented, that are based on the Poisson sampling and proved more efficient. The selection of primary sampling units is also illustrated for tuberculosis prevalence surveys, which are recommended in many countries and supported by the World Health Organisation as an emblematic example of the need for an improved sampling design. Simulation results are given in the tuberculosis application to illustrate the strengths and weaknesses of the proposed sequential adaptive sampling strategies with respect to traditional cross-sectional non-informative sampling as currently suggested by World Health Organisation guidelines.

A case study of multiple individuals with a supernumerary vertebra and sacralization in the prehistoric Rio Muerto Tiwanaku cemetery (AD 700-900), Moquegua, Peru

This paper presents a rare cluster of 16 Tiwanaku colonists (AD 700-1000) buried in the Rio Muerto cemeteries M70B and M43A (Moquegua Valley, Peru) who have a supernumerary sixth lumbar (L6) vertebra in their complete spine. While some nonhuman primates have an extra lumbar vertebra for quadrupedal flexibility, an additional lumbar vertebra in humans is considered a rare trait and associated with a Hox gene mutation. More than half of adolescent and older individuals in the study population were observed to have this trait (M70B: 14 of 26; M43A: 2 of 3). Almost all these people also have full or partial L6 sacralization. At least three other Tiwanaku colonists within the Moquegua Valley have been noted with this trait, as well as one case from the Tiwanaku heartland site of Lukurmata, Bolivia. Finding this many people with this rare condition concentrated in one archaeological site suggests a shared connection, such as a congenital condition. We discuss the distribution of this trait at the Rio Muerto site, and how this may represent a subgroup of a migrant community within the larger Tiwanaku population. We also consider mortuary evidence and previously published strontium indications of migration, potential shared descent, community connections, and studies of intermarriage within this region.

A new species of Anatextrix Kaya, Zamani, Yağmur &amp;amp; Marusik, 2023 (Araneae, Agelenidae, Textricini) from southern Türkiye, with a remarkable morphology of the male palpal femur

Anatextrix monstrabilissp. nov. (Araneae: Agelenidae) is described and illustrated, based on male and female specimens collected from Adana Province, Türkiye. The new species has an L-shaped male palpal femur bearing multiple apophyses, which is a rare trait in spiders. Anatextrix monstrabilissp. nov. is the second species of the recently described genus Anatextrix Kaya, Zamani, Yağmur &amp; Marusik, 2023, currently known only from southern Türkiye.

Are cleaning interactions offered by large cleaners positive?

ABSTRACT Cleaning symbiosis is a cooperative interspecific interaction among reef fishes that helps to maintain healthy marine communities. Despite its importance, our knowledge on the cleaner role of many species, and on the costs and benefits of these interactions, is still scarce. Here, we report for the first time an adult Guinean angelfish Holacanthus africanus acting as cleaner of the smaller client blackbar soldierfish Myripristis jacobus in the remote Cabo Verde Archipelago, Eastern Atlantic. Adult angelfish cleaning behaviour is a rare juvenile trait retention, which based on our observations could have a negative effect on smaller clients. This negative effect can be associated with the fish’s extra lower jaw joint, adapted to extract sessile invertebrates from the substrate, which can remove the client’s tissues during the cleaning attempt. Thus, although cleaning interactions have been viewed as examples of marine mutualisms, the costs and benefits of cleaning for cleaners and clients require more studies. Our study also builds on the scarce information on cleaning behaviour of adult fishes and offers highlights on this symbiosis in isolated locations with low species richness and absence of dedicated cleaners.

Characterization of Streptococcus equi subsp. zooepidemicus isolates containing lnuB gene responsible for the L phenotype.

Within the framework of the β-hemolytic streptococci surveillance carried out by the National Reference Laboratory from Uruguay, three putative Streptococcus equi subsp. zooepidemicus (SEZ) were received from different health centers. Being these the first reports associated with human infections in Uruguay, the objective of this work was to confirm their identification, to determine their genetic relationship and to study their antibiotic susceptibility. Using four different methods, they were identified as SEZ, a subspecies which has been described as the etiologic agent of rare and severe zoonosis in a few cases in other countries. The three isolates presented different pulsotypes by PFGE; however, two of them appeared to be related and were confirmed as ST431 by MLST, while the remaining isolate displayed ST72. Their resistance profile exhibited an unexpected feature: despite all of them were susceptible to macrolides, they showed different levels of resistance to clindamycin, i.e. they had the so-called "L phenotype". This rare trait is known to be due to a nucleotidyl-transferase, encoded by genes of the lnu family. Although this phenotype was previously described in a few SEZ isolates, its genetic basis has not been studied yet. This was now analyzed by PCR in the three isolates and they were found to contain a lnuB gene. The lnuB sequence was identical among the three isolates and with many lnuB sequences deposited in data banks. In conclusion, for the first time in Uruguay, three SEZ isolates recovered from non-epidemiologically related cases of human invasive infection were identified. Moreover, this is the first report about the presence of a lnu gene in the S. equi species, revealing the active lateral spread of the lnuB in a new streptococcal host.

Bi-allelic variants in the ESAM tight-junction gene cause a neurodevelopmental disorder associated with fetal intracranial hemorrhage

The blood-brain barrier (BBB) is an essential gatekeeper for the central nervous system and incidence of neurodevelopmental disorders (NDDs) is higher in infants with a history of intracerebral hemorrhage (ICH). We discovered a rare disease trait in thirteen individuals, including four fetuses, from eight unrelated families associated with homozygous loss-of-function variant alleles of ESAM which encodes an endothelial cell adhesion molecule. The c.115del (p.Arg39Glyfs∗33) variant, identified in six individuals from four independent families of Southeastern Anatolia, severely impaired the invitro tubulogenic process of endothelial colony-forming cells, recapitulating previous evidence in null mice, and caused lack of ESAM expression in the capillary endothelial cells of damaged brain. Affected individuals with bi-allelic ESAM variants showed profound global developmental delay/unspecified intellectual disability, epilepsy, absent or severely delayed speech, varying degrees of spasticity, ventriculomegaly, and ICH/cerebral calcifications, the latter being also observed in the fetuses. Phenotypic traits observed in individuals with bi-allelic ESAM variants overlap very closely with other known conditions characterized by endothelial dysfunction due to mutation of genes encoding tight junction molecules. Our findings emphasize the role of brain endothelial dysfunction in NDDs and contribute to the expansion of an emerging group of diseases that we propose to rename as "tightjunctionopathies."

Higher functional diversity improves modeling of Amazon forest carbon storage

The impacts of reduced precipitation on plant functional diversity and how its components (richness, evenness, divergence and composition) modulate the Amazon carbon balance remain elusive. We present a novel trait-based approach, the CArbon and Ecosystem functional-Trait Evaluation (CAETÊ) model to investigate the role of plant trait diversity in representing vegetation carbon (C) storage and net primary productivity (NPP) in current climatic conditions. We assess impacts of plant functional diversity on vegetation C storage under low precipitation in the Amazon basin, by employing two approaches (low and high plant trait diversity, respectively): (i) a plant functional type (PFT) approach comprising three PFTs, and (ii) a trait-based approach representing 3000 plant life strategies (PLSs). The PFTs/PLSs are defined by combinations of six traits: C allocation and residence time in leaves, wood, and fine roots. We found that including trait variability improved the model's performance in representing NPP and vegetation C storage in the Amazon. When considering the whole basin, simulated reductions in precipitation caused vegetation C storage loss by ∼60% for both model approaches, while the PFT approach simulated a more widespread C loss and abrupt changes in neighboring grid cells. We found that owing to high trait variability in the trait-based approach, the plant community was able to functionally reorganize itself via changes in the relative abundance of different plant life strategies, which therefore resulted in the emergence of previously rare trait combinations in the model simulation. The trait-based approach yielded strategies that invest more heavily in fine roots to deal with limited water availability, which allowed the occupation of grid cells where none of the PFTs were able to establish. The prioritization of root investment at the expense of other tissues in response to drought has been observed in other studies. However, the higher investment in roots also had consequences: it resulted, for the trait-based approach, in a higher root:shoot ratio (a mean increase of 74.74%) leading to a lower vegetation C storage in some grid cells. Our findings highlight that accounting for plant functional diversity is crucial when evaluating the sensitivity of the Amazon forest to climate change, and therefore allow for a more mechanistic understanding of the role of biodiversity for tropical forest ecosystem functioning.

The dentition of the Early Upper Paleolithic hominins from Ksâr ‘Akil, Lebanon

There are scant human remains associated with Early Upper Paleolithic (EUP) industries. The rock shelter at Ksâr ‘Akil, Lebanon, is one of the few circum-Mediterranean archaeological sites with EUP artifacts and associated fossils attributed to Homo sapiens. The skull and post-crania of the juvenile ‘Egbert’ (Ksâr ‘Akil 1) from the EUP levels (conservatively dated from ∼43 to 39 ka) have been lost; the partial edentulous maxilla of ‘Ethelruda’ (Ksâr ‘Akil 2) from the Initial Upper Paleolithic levels has only recently been rediscovered, leaving an isolated deciduous molar (Ksâr ‘Akil 3) from Levantine Aurignacian strata. A fourth individual was found adjacent to Ksâr ‘Akil 1 in 1938, but never described, and is apparently also lost. New archival research at the Peabody Museum of Archaeology and Ethnography uncovered photographs and radiographs of Ksâr ‘Akil 1 and photographs of the fourth individual (which we designate Ksâr ‘Akil 4). These new photographs and radiographs allow a comparative dental analysis of both individuals. Radiographs confirm an age of 7–8 years for Ksâr ‘Akil 1 and photographs of Ksâr ‘Akil 4 suggest a similar, if not slightly younger, age. Compared to other fossil H. sapiens, the teeth of Ksâr ‘Akil 1 and Ksâr ‘Akil 4 are remarkably modern. The upper deciduous third premolars lack a hypocone and metacone; the upper deciduous fourth premolars of Ksâr ‘Akil 1 have reduced hypocones and both individuals have upper fourth premolars and first molars with square (as opposed to skewed) occlusal outlines, resulting from a hypocone that is smaller than, or equal in size to, the metacone. The lower first permanent molars of Ksâr ‘Akil 1, and possibly Ksâr ‘Akil 4, are four-cusped, which is a rare trait among Paleolithic and recent H. sapiens.