Fossils of Orrorin record the first convincing evidence of hominid terrestrial bipedalism in the Late Miocene, at about six million years ago. Bipedalism in the slightly older (7 Ma old) Sahelanthropus has recently been called into question. Here we present the first known hominine postcranial element from Azmaka (Bulgaria), a 7.2 Ma old nearly complete femur, which we tentatively attribute to cf. Graecopithecus. The Azmaka hominine represents a candidate for the ancestral form of positional behaviour from which bipedalism documented in later hominins evolved. The Azmaka femur lacks many of the specialised attributes of arboreal quadrupeds. At the same time the combination of locomotor features of this femur indicates a complex locomotor repertoire. Qualitative and quantitative morphological analyses demonstrate that the Azmaka femur combines certain attributes of terrestrial quadrupeds and bipeds and clusters mostly with early bipeds and partially with African apes. The morphology indicates a transitional form of bipedalism. The wooded-grassland savanna environment of the early Messinian locality of Azmaka suggests that terrestrial bipedalism likely evolved in a non-forested setting. The early Messinian age is critical to our understanding of mammalian palaeobiogeography and the intercontinental dispersals between Eurasia and Africa. We hypothesise that the descendants of the Azmaka hominine may have dispersed from Eurasia into Africa under the influence of climatic and environmental changes in the eastern Mediterranean. If such dispersal occurred, it may have been associated with subsequent re-occupation of more forested settings in both the ancestors of African apes and hominins.

Ascending and descending sloping and vertical branches are critical for arboreal locomotion and likely played a major role in early primate evolution. While most studies have focused on ascent, descending behaviors also provide insight into the functional significance of arboreal adaptations. To test how descending vertical supports of varying diameters affect locomotor abilities, we quantified postural and kinematic features during descents and ascents on vertical supports in 21 eutherian and metatherian mammals and examined their relation to morphology. Primates showed greater variability in descent behaviors, using tail-first and side postures more often than other mammals, which predominantly descended head-first. Overall, animals adopted several kinematic adjustments to enhance stability during descent compared to ascent, including slower speeds, higher duty factors, and greater use of asymmetrical gaits. Additionally, vertical descent strategies reflected trade-offs among body mass, limb proportions, and head mass. Using a morphology-based model, we then inferred possible descent behaviors in 13 extinct euarchontoglires. Our results suggest that ancestral adaptations for vertical locomotion may have promoted frequent upright (head-up) postures in early primates.

Arboreal locomotion in small mammals requires the integration of behavioral and morphological adaptations to negotiate complex three-dimensional environments. The present study investigates the locomotor and postural behavior of captive Acacia rats (Thallomys paedulcus) to evaluate their arboreal capacities. A total of 21 adult individuals were observed under controlled conditions, and behavioral data were collected from video recordings using continuous bout sampling. Substrate size, inclination, and type were recorded alongside locomotor and postural modes, and substrate preferences were assessed relative to availability. Results show that Acacia rats predominantly used arboreal substrates, with a strong preference for small-diameter and horizontal supports during both locomotion and postural activities. Quadrupedalism was the dominant locomotor mode, followed by climb and clamber, while bridge and leap were used for gap crossing. Postural behavior was mainly characterized by stand, with less frequent sit, bipedal stand, and cling. Medium and large substrates, as well as oblique and vertical supports, were generally avoided, particularly during postural behavior. These findings indicate a high degree of behavioral specialization for exploiting fine terminal branches within tree canopies. The results support the arboreal propensities of Acacia rats, with adaptations primarily expressed through behavioral selectivity rather than morphological divergence. This study contributes to understanding the ecological and functional adaptations of small arboreal mammals and highlights the importance of structurally complex habitats for their survival.

The forest dormouse (Dryomys nitedula) is a small, nocturnal, arboreal rodent widely distributed across Central and Eastern Europe. Yet, it remains one of the least studied European glirid species, with information on its ecology in southern populations being scarce. This study presents the first systematic investigation of the diel (24 h) activity patterns of D. nitedula in Greece. From March to December 2024, camera traps were deployed on trees facing branches or artificial nest boxes at 26 locations within a 30 ha forest-meadow mosaic in Northern Greece. Based on 958 independent detections at 22 sites, activity was highest at nest boxes and exhibited two nocturnal peaks that were consistent across seasons: a major one around midnight and a secondary one before sunrise. Temporal activity overlap between nest-box cameras and branch-facing cameras was high across all seasons. Activity, measured as the number of independent detections per night, was highest during short, humid nights with low levels of moonlight. Temperature and precipitation were not good predictors of activity levels. These findings confirm that the behavior of D. nitedula is predominantly nocturnal and reveal key environmental drivers shaping its activity in the Mediterranean region. Moreover, this study highlights the value of camera trapping as a non-invasive method for monitoring small arboreal mammals and provides essential baseline data for future ecological and conservation research on this understudied species.

Understanding fine-scale spatial ecology is essential for defining effective conservation priorities, particularly at the range margins of vulnerable species. Here, we investigate the spatial ecology and habitat associations of the Persian squirrel (Sciurus anomalus) on Lesvos Island, Greece, representing the species’ westernmost distribution. Using a randomized grid-based survey, we recorded 424 presence records across the island and applied a suite of spatial analyses, including Kernel Density Estimation, Getis-Ord Gi*, and Anselin Local Moran’s I, to detect hotspots, coldspots, and spatial outliers. Binomial Logistic Regression, supported by Principal Component Analysis, identified key ecological drivers of habitat use, while spatial regression models (Spatial Lag and Spatial Error Models) quantified the influence of land-use characteristics and spatial dependencies on hotspot intensity and clustering dynamics. Our results showed that hotspots were primarily associated with olive-dominated and broadleaved landscapes, while coldspots and Low–Low clusters were concentrated in fragmented or degraded habitats, often outside protected areas. Spatial outliers revealed fine-scale deviations from broader patterns, indicating local habitat disruptions and emerging conservation risks not captured by existing Natura 2000 boundaries. Spatial regression confirmed that both hotspot intensity and clustering patterns were shaped by specific land-use features and spatially structured processes. Collectively, our findings underscore the fragmented nature of suitable habitats and the absence of cohesive population cores, reinforcing the need for connectivity-focused, landscape-scale conservation.

The southeastern edge of the Qinghai-Tibet Plateau (Yunnan, China) exhibits high biodiversity but stark differences in species richness between its western Longitudinal Range Gorge (LRG) and eastern Yunnan Plateau (YP). We collected distribution data for 16 primate species in Yunnan and analyzed palynological records over the past 20 ka from 21 localities to identify the biogeographic, climatic, and anthropogenic factors that have driven the present-day distribution of primates in this region. By integrating local ecological knowledge, field surveys, species distribution models, niche utilization rates, and historical vegetation and land use changes, we found that spatial-temporal shifts in the monsoon climate have been a critical factor in shaping primate species richness on the southeastern edge of the Qinghai-Tibet Plateau. Compared to the YP, the LRG receives more precipitation, has more limited seasonal temperature variation, and has higher minimum temperatures during the coldest month. These conditions have facilitated the development of moist evergreen broadleaf forests, which represent a more suitable habitat for the 14 primate species that inhabit this area. In contrast, the drought-adapted forests of the YP support only one primate species. Palynological records indicate that the differentiation of the LRG and YP predates human influence. However, over the past 2000  years, anthropogenic habitat loss and hunting have significantly affected the distribution of primates. The ranges of gibbons, langurs, and snub-nosed monkeys are now restricted to the central and northern regions of the LRG and have disappeared from lower elevations. Lorises have disappeared from their northernmost range. In contrast, the distribution of macaques has remained relatively stable. The Yangtze-Red River-24° N line marks the biogeographic boundary of high primate species richness and biodiversity in the LRG and southeastern Yunnan. Our research suggests that changes in monsoon climate have fundamentally shaped contemporary species richness, while recent anthropogenic pressures have caused 'range contraction' for many taxa.

We present a genome assembly from a female Spermophilus citellus (European ground squirrel; Chordata; Mammalia; Rodentia; Sciuridae). The genome sequence has a total length of 3,090.03 megabases. Most of the assembly (95.47%) is scaffolded into 20 chromosomal pseudomolecules, including the X sex chromosome. The mitochondrial genome has also been assembled, with a length of 16.45 kilobases.

A tooth-bearing mandible fossil of a colobine monkey discovered at Shuitangba, Zhaotong, Yunnan, China, was morphometrically analyzed and compared with extant Asian colobines. Our previous qualitative and quantitative descriptions indicate that it can be safely attributed to Mesopithecus pentelicus, a Miocene fossil colobine widely found in Europe and South Asia. The present research aims to explore fossil association with extant colobines and functionally propose its dietary preferences based on multivariate morphometric analyses of mandibular morphology. The results indicate that this fossil species presents a mosaic association with extant langurs (Presbytis, Trachypithecus, and Semnopithecus) and odd-nosed monkeys (Pygathrix, Nasalis, and Rhinopithecus), with most similarities of size-related traits and size-adjusted shapes, and a notable difference from extant Rhinopithecus, due to the increased body size of the latter since the Pliocene. The allometric analysis showed that, like the fossils of the same species in other sites, its mandibular structure appears more adapted to crushing hard seed shells than chewing leaves. Moreover, our findings also imply that the Asian colobines significantly modified their dietary preferences over the last 6 million years following the ecological and environmental changes triggered by the accelerated uplift of the Qinghai-Tibet Plateaus and severe monsoons. Morphologically, the more developed condyle length and moment arms of the temporomandibular joint and medial pterygoid muscles appear to accommodate a more folivorous dietary selection, functionally related to the intake of rigid fibers in leaves that require frequent one or two-side mandibular chewing and grinding.

The European wildcat exhibits considerable plasticity in its habitat requirements across its distribution, with differences increasing along a continental-scale latitudinal gradient. While wildcats often favor deciduous and mixed forests with dense cover and prey, studies show these preferences vary across their expansion. Range-wide conservation efforts will benefit from incorporating knowledge generated by robust regional ecological models. We used data from a large camera trap grid (n = 292 stations), spanning across eight wildcat-associated habitats, within its range in northern Greece, to understand the regional ecological parameters affecting the species’ habitat selection. We analyzed the data using single-season density-induced detection heterogeneity occupancy models (Royle–Nichols), considering 12 environmental and anthropogenic parameters. The global model’s GoF was high (p = 0.9). Elevation and percent forest cover were both significantly negatively related to wildcat occupancy (as derived from the modeled “relative abundance index” N). Likewise, there was a negative, but moderate, relation between distance to freshwater bodies and human settlements with wildcat occupancy. We used the model-average coefficients to generate a predictive map of wildcat relative abundance across northern Greece, which identified 47,930 km2 of potential wildcat habitat. Assuming a range of densities between 0.05 and 0.3 ind/km2 in areas with predicted low, medium, and high relative abundance, we speculate the putative wildcat population in northern Greece to be between 3535 and 7070 individuals. The findings, which vary from ecological models of the species in northern Europe, show the need for regional models and the importance of Greece, and the Balkan peninsula, for the species.

Studies of positional (=locomotor and postural) behavior are central to understanding how animals interact with the challenges imposed by their environment and are crucial for conservation management. The present study investigates, for the first time, the positional behavior and substrate use of the endangered southern pygmy slow loris Xanthonycticebus pygmaeus. Despite their very specialized morphology and ecology, the positional behavior of lorises is understudied. Behavioral data were collected using 30-s scan instant sampling on seven captive animals housed in a large, enriched enclosure of the Poznań Nowe Zoo (Poland) during February–June 2013. Pygmy slow lorises were almost exclusively arboreal and most activities occurred on multiple substrates (82.93%). Small (57.91%) and large (28.28%) substrates were extensively used. Horizontal (42.11%) and oblique (38.47%) substrates dominated. Clamber (39.39%), quadrupedalism (33.77%), and vertical climb (17.62%) were the main locomotor modes. Standing was the dominant posture (47.23%), followed by hanging (27.32%) and clinging (11.31%). Our results concur with the limited observations available on other lorisines; pygmy slow lorises employed a diverse and flexible positional repertoire as an adaptation to the exploitation of the continuous forest layers with intertwined small substrates of various inclinations. Consequently, protecting and managing these habitats, supported by ex situ reintroduction programs, can effectively contribute to the conservation of the species’ populations.

The locomotor behavior and substrate preferences of early colobines are a matter of debate. Some researchers advocate a partly terrestrial origin with the subsequent parallel evolution of arboreality in different clades during the Plio-Pleistocene, while others suggest that arboreality had already evolved earlier in the Miocene. Microcolobus, from the Late Miocene of Nakali (ca. 10 Ma, Kenya), is one of the earliest known and, for the most part, best-documented African Miocene fossil colobines. A large collection of postcranial remains was recovered at Nakali during the fieldwork of the Joint Japan-Kenya Paleontological Expedition, permitting us to test hypotheses regarding the locomotor behavior, substrate preferences, and taxonomy of the Nakali colobines. Here, we present novel interpretations of the functional adaptations of the elbow anatomy of previously published partial skeletons from Nakali (KNM-NA 47916 and KNM-NA 47915) and the description of 12 additional humeral, ulnar, and radial specimens that we attributed to Microcolobus. The elbow specimens from Nakali are morphologically homogenous except one humeral specimen that demonstrates equivocal evidence of functional and taxonomical diversity. Quantitative and qualitative analyses confirm arboreal adaptations of Microcolobus, corroborating hypotheses supporting early adaptations for arboreal locomotor substrate preferences in colobines. The elbow anatomy of Microcolobus can be qualitatively and quantitatively distinguished from that of the Late Miocene colobines Cercopithecoides bruneti and Paracolobus enkorikae. Microcolobus also present several anatomical features seen in the small African colobine Procolobus verus, reflecting a frequently flexed elbow with moderate pronosupination abilities and a stable humeroulnar joint consistent with the use of flexed-elbow climbing and arboreal quadrupedal running.

Traditional centennial olive groves represent ecologically valuable agroecosystems that support both biodiversity and cultural heritage across Mediterranean landscapes. On Lesvos Island, Greece, which marks the westernmost limit of the Persian squirrel (Sciurus anomalus) distribution, these centennial olive trees serve as essential nesting resources for this regionally Vulnerable species. However, the tree-level mechanisms determining den-site suitability remain insufficiently understood. We examined 288 centennial olive trees, including 36 with confirmed dens, integrating structural, physiological, and thermal metrics to identify the attributes influencing den occupancy. Our results showed that squirrels consistently selected older and taller olives with broad crowns and high photosynthetic activity, indicating a preference for vigorous, architecturally complex trees that provide stable microclimatic conditions. Infrared thermography revealed that occupied trees exhibited lower trunk temperature asymmetries and stronger thermal buffering capacity, highlighting the role of microclimatic stability in den-site selection. Overall, our findings show that den-site selection in S. anomalus is shaped by the interplay of structural maturity, physiological performance, and thermal coherence. By linking tree function to den-site suitability, our work advances a mechanistic understanding of microhabitat selection and emphasizes the importance of centennial olive trees as biophysical refugia within traditional Mediterranean agroecosystems.

We present a genome assembly from a female Spermophilus citellus (European ground squirrel; Chordata; Mammalia; Rodentia; Sciuridae). The genome sequence has a total length of 3,090.03 megabases. Most of the assembly (95.47%) is scaffolded into 20 chromosomal pseudomolecules, including the X sex chromosome. The mitochondrial genome has also been assembled, with a length of 16.45 kilobases.

The European ground squirrel (Spermophilus citellus) is an endangered mammal that inhabits open habitats with low vegetation in central and southeastern Europe. Its southernmost range includes northern Greece, where populations are declining due to habitat degradation and fragmentation. Limited behavioural research on Greek populations underscores the need for studies to support conservation efforts. The present study examined the species’ diet and seasonal changes in food consumption in an anthropogenic area of Central Macedonia, Greece. Between 2022 and 2023, feeding behaviour was documented recording plant parts, taxa, and feeding durations, while plant availability was assessed through surface sampling. The results revealed that Cynodon, Carex–Cyperus, Salvia, Solanum, and Plantago were the dominant plant genera in the species’ diet, while rhizomes and leaves were the most frequently consumed plant parts. Seasonal dietary shifts were observed, with ground squirrels selecting specific plants and plant parts based on availability. Under resource-limited conditions, they adapted by consuming nutritious rhizomes or the less-common, but toxic, S. elaeagnifolium. These findings highlight the species’ dietary adaptability to Mediterranean and human-modified environments, providing valuable ecological insights and informing habitat conservation and improvement strategies.

The evolutionary development and phylogenetic division between Asian and African cercopithecoids (Cercopithecidae) have attracted significant attention in genetics, molecular biology, behavior, and morphology. However, less emphasis has been placed on how they have evolved morphologically after divergence, approximately 10 million years ago (mya) for Colobinae and 5–7 mya for Cercopithecinae, corresponding to the significant variation and diversity in landscape, climate, habitat, and ecologies between the two continents. This study examines whether such variation and diversity have been reflected in dental morphology. Our findings reveal substantial differences between Hylobatidae and Cercopithecidae, as well as between Colobinae and Cercopithecinae, indicating that size-adjusted dental variation mainly reveals the diversity associated with evolution and phylogenetic inertia. Interestingly, despite the earlier divergence of Afro-Asian colobines, their Euclidean Distance is comparable to that of Afro-Asian cercopithecines. This implies that latecomers (macaques) demonstrate equivalent diversity to colobines due to their extensive dispersion and broader adaptative radiation on the same continent. Colobinae exhibit more developed premolar and molar regions. However, when post-canine teeth are considered alone, Colobinae present a significantly larger molar size than Asian Cercopithecinae but not with the African Cercopihecinae. This contradicts the hypothesis that folivorous primates (Colobinae) have larger post-canine molars than frugivorous ones (Cercopithecinae). The considerable molar size in African Cercopithecinae must be associated with their more protrusive and larger facial structure rather than a specific dietary preference, being less diverse than their Asian counterparts—a trait that has evolved phylogenetically. This study also paves the way for further exploration of facial and cranial differences between the continental groups of Cercopithecinae and Colobinae, delving deeply into diversity variation due to geographical and climatic adaptations.

our sites in northern Greece, presented here, are of particular interest, due to the presence of fossil primates and carnivores in Late Miocene and Pliocene assemblages. The Thermopigi site in eastern Macedonia is particularly important, due to its demonstrable Late Miocene assemblage of more than twenty different species of large mammals, including the postcranial remains (humerus, tibia, calcaneus) of the colobine Mesopithecus delsoni. Carnivores from this site, represented by hyenids, felids, and mustelids, are also described here. Among them, the hyper-carnivorous and widely spread Adcrocuta eximia, an important biostratigraphic marker of Late Miocene, is compared with the single skull from the nearby site of Platania (Drama), both of great taphonomic interest. The site of Milia (Grevena), in Western Macedonia, is also of particular importance, as it includes the earliest Villafranchian age assemblage. New primate material, an ulna and tibia attributed to aff. Dolichopithecus sp. are also described here. Among the new carnivore finds, an incomplete distal tibia belongs to a new felid for the Milia locality, most likely attributable to either a female Megantereon or a new species of Puma. Further investigations are necessary to confirm either attribution. Finally, the new Pliocene site at Promachonas (Serres), mentioned here for the first time, yielded dental material, most likely belonging to cf. Dolichopithecus balcanicus. This study of new material from these sites contributes to a better knowledge regarding the occurrence of primates and carnivores and their paleoenvironments in northern Greece.

Apart from northern and central China, the fossil record of the latest Miocene and Early Pliocene of Asia is not well documented and the record of South China during this interval is especially poor. Shuitangba, a site in Yunnan Province, offers a rare window into the paleoenvironment of the latest Miocene in southwestern China. Over 2400 vertebrate and macrobotanical specimens have been recovered from the site. The faunal assemblage is dominated by aquatic avian taxa and many of the mammalian taxa are those that indicate densely vegetated, water-margin habitats. Pollen and carpological remains indicate a temperate to subtropical, broad-leaved/coniferous forest around standing water, with more open areas containing grasses and herbs. Analyses of clay minerals, chemical weathering, and enamel stable isotopes suggest that Shuitangba was warmer and more humid than today, possibly with more pronounced seasonality. Results of community structure analysis indicate that the Shuitangba mammalian community was different from those of other Late Miocene Chinese sites in the high proportions of aquatic-dependent mammalian taxa. While Shuitangba shared mammalian faunal elements with other Late Miocene sites in Yunnan, it was still faunally distinct. Further, Shuitangba was depauperate in its mammalian fauna, which may have been a result of the depositional setting rather than a true reflection of regional faunal diversity.

Climate change can be expected to alter ecosystems and influence the spatial distribution of species. Understanding the effects of climate change on species distribution can help develop effective conservation protocols to tackle further biodiversity loss. Striped hyena (Hyaena hyaena) global populations appear to follow an overall decreasing trend as the species faces numerous threats. Hyena presence location data was collected, and we utilized a Maxent species distribution model to predict current and future distribution patterns in Nepal. We used two distinct representative concentration pathway (RCP) values (RCP 4.5 and RCP 8.5) to determine potential impacts on hyena distribution. We found that hyena current suitable habitat in Nepal extends over 22,000 km(2) and is projected to significantly decrease in both (RCP 4.5 and RCP 8.5) scenarios. In terms of habitat reduction, we further showed that RCP 8.5 was more adverse than RCP 4.5. We found that the Chure hills and the Terai regions hold the largest extent of hyena habitat in Nepal. Hyena habitat reduction was comparatively lower within the protected areas. Future projections, however, portend severe consequences for the species' survival as suitable habitat areas will be drastically reduced in the next 50 years. Further research on hyena microhabitat suitability under anthropogenic and topographic variables will be useful for future conservation policies.