Hand and foot morphology maps invasion of terrestrial environments by pterosaurs in the mid-Mesozoic.

Pterosaurs, the first true flying vertebrates, played a crucial role in Mesozoic terrestrial ecosystems. However, our understanding of their ability to move around on the ground and, more broadly, their terrestrial paleoecology remains limited. Here, we demonstrate an unexpectedly high degree of variation in the hands and feet of pterosaurs, comparable with that observed in extant birds. This suggests that pterosaurs were adapted to a remarkably broad range of non-aerial locomotor ecologies. Small, early, long-tailed pterosaurs (non-pterodactyliforms) exhibit extreme modifications in their hand and foot proportions indicative of climbing lifestyles. By contrast, the hands and feet of later, short-tailed pterosaurs (pterodactyliforms) typically exhibit morphologies consistent with more ground-based locomotor ecologies. These changes in proportions correlate with other modifications to pterosaur anatomy, critically, the separation along the midline of the flight membrane (cruropatagium) that linked the hindlimbs, enabling a much more effective locomotory ability on the ground. Together, these changes map a significant event in tetrapod evolution: a mid-Mesozoic colonization of terrestrial environments by short-tailed pterosaurs. This transition to predominantly ground-based locomotor ecologies did not occur as a single event coinciding with the origin of short-tailed forms but evolved independently within each of the four principal radiations: euctenochasmatians, ornithocheiroids, dsungaripteroids, and azhdarchoids. Invasion of terrestrial environments by pterosaurs facilitated the evolution of a wide range of novel feeding ecologies, while the freedom from limitations imposed by climbing permitted an increase in body size, ultimately enabling the evolution of gigantism in multiple lineages.

Center of mass mechanics during locomotion in the arboreal squirrel monkey (Saimiri sciureus) as a function of speed and substrate.

It is thought that the magnitude of center of mass (COM) oscillations can affect stability and locomotor costs in arboreal animals. Previous studies have suggested that minimizing collisional losses and maximizing pendular energy exchange are effective mechanisms to reduce muscular input and energy expenditure during terrestrial locomotion. However, few studies have explored whether these mechanisms are used in an arboreal context, where stability and efficiency often act as tradeoffs. This study explores three-dimensional center of mass mechanics in an arboreal primate-the squirrel monkey (Saimiri sciureus)-moving quadrupedally at various speeds on instrumented arboreal and terrestrial supports. Using kinetic data, values of energy recovery, center of mass mechanical work and power, potential and kinetic energy congruity, and collision angle and fraction were calculated for each stride. Saimiri differed from many other mammals by having lower energy recovery. Although few differences were observed in center of mass mechanics between substrates at low or moderate speeds, as speed increased, center of mass work was done at a much greater range of rates on the pole. Collision angles were higher, while collision fractions and energy recovery values were lower on the pole, indicating less moderation of collisional losses during arboreal versus terrestrial locomotion. These data support the idea that the energetic demands of arboreal and terrestrial locomotion differ, suggesting that arboreal primates likely employ different locomotor strategies compared to their terrestrial counterparts-an important factor in the evolution of arboreal locomotion.

Colony life history of the tropical arboreal ant, Cephalotes goniodontus De Andrade, 1999.

Arboreal ants are ecologically important in tropical forests, but there are few studies using DNA markers to examine their population and colony structure. Colonies of the arboreal turtle ant Cephalotes goniodontus create trail networks through the canopy of the tropical forest, in dense vegetation where it is difficult to determine how long a nest is used and how neighboring colonies partition space. We monitored 53 nest sites for up to six years and, using seven microsatellite markers, genotyped samples of workers collected at or near 41 nests over 1-4 years. We calculated average relatedness within samples collected at a given location, and between samples collected at the same location in successive years, and performed pedigree analysis to predict the number of queens that produced each sample of workers. Fifteen samples were highly related (r ≥ 0.6) from single colonies, of which 11 were monogynous and the remaining four had two queens; 19 were of intermediate relatedness (0.1 ≤ r < 0.6) with 1-6 queens, and 7 were groups of unrelated workers (r < 0.1) from at least 4 queens. Colonies persisted at the same nest site for 2-6 years. The smallest distance we found separating nests of different colonies was 16.2 m. It appears that different colonies may share foraging trails. Our study demonstrates the feasibility of using a cost-efficient genotyping method to provide information on colony structure and life history of ant species. Supplementary Information: The online version contains supplementary material available at 10.1007/s00040-024-00974-3.

Mandibular gland proteomics of the Mexican alligator lizard, Abronia graminea, and the red-lipped arboreal alligator lizard, Abronia lythrochila.

A useful approach to deepen our knowledge about the origin and evolution of venom systems in Reptilia has been exploring the vast biodiversity of this clade of vertebrates in search of orally produced proteins with toxic actions, as well as their corresponding delivery systems. The occurrence of toxins in anguimorph lizards has been demonstrated experimentally or inferred from reports of the toxic effects of the oral secretions of taxa within the Varanidae and Helodermatidae families. In the present study, we have focused on two alligator lizards of the Anguidae family, the Mexican alligator lizard, Abronia graminea, and the red-lipped arboreal alligator lizard, A. lythrochila. In addition, the fine morphology of teeth of the latter species is described. The presence of a conserved set of proteins, including B-type natriuretic peptides, cysteine-rich secretory proteins, group III phospholipase A2, and kallikrein, in submandibular gland extracts was demonstrated for both Abronia species. These proteins belong to toxin families found in oral gland secretions of venomous reptile species. This finding, along with previous demonstration of toxin-producing taxa in both paleo- and neoanguimorpha clades, provides further support for the existence of a handful of conserved toxin families in oral secretions across the 100+ million years of Anguimorpha cladogenesis.

A shift towards softer pest management differently benefits earwig and spider communities in a multiyear experiment in apple orchards.

BACKGROUND: Environmentally-friendly crop protection practices are needed to enhance the sustainability of current agricultural systems. This is crucial in orchards which are extensively treated to impair various pests, at the expense of natural enemies. However, the effect of a shift towards softer pest management on the beneficial arthropod community is poorly documented. Earwigs (Dermaptera: Forficulidae) and spiders (Araneae) are relevant groups to assess such effects because they are highly sensitive to agricultural practices. They were monitored for 6 and 4 years, respectively, in apple orchards under three pest management regimes: Organic, Low-input and Conventional, with pest management being switched during the survey from a broad-spectrum insecticide schedule to mating disruption in the latter one, and more selective compounds in all orchards. RESULTS: The survey displayed that earwig abundance (mainly Forficula auricularia) that was initially very low in the Conventional orchard (annual mean 0.5-1.7 earwigs per shelter in the 2010-2012 period) increased to the same level as that of Low-input and Organic orchards (over 10 earwigs per shelter) in the same year that changes in pest management occurred. The epigeal and arboreal spider communities were not responsive, and no recovering was observed 4 years after change in practices. CONCLUSION: Predatory arthropod communities are differently affected over time by changes in pest management, most probably due to their biology (dispersion, reproduction rate, susceptibility to pesticides etc.). This outlines the importance of documenting the time required to recover after perturbations and build a natural enemy community to enhance pest control in a win-win perspective. © 2024 Society of Chemical Industry.

Hot climate, hot koalas: the role of weather, behaviour and disease on thermoregulation.

Thermoregulation is critical for endotherms living in hot, dry conditions, and maintaining optimal core body temperature (Tb) in a changing climate is an increasingly challenging task for mammals. Koalas (Phascolarctos cinereus) have evolved physiological and behavioural strategies to maintain homeostasis and regulate their Tb but are thought to be vulnerable to prolonged heat. We investigated how weather, behaviour and disease influence Tb for wild, free-living koalas during summer in north-west New South Wales. We matched Tb with daily behavioural observations in an ageing population where chlamydial disease is prevalent. Each individual koala had similar Tb rhythms (average Tb = 36.4 ± 0.05°C), but male koalas had higher Tb amplitude and more pronounced daily rhythm than females. Disease disrupted the 24-hr circadian pattern of Tb. Koala Tb increased with ambient temperature (Ta). On the hottest day of the study (maximum Ta = 40.8°C), we recorded the highest (Tb = 40.8°C) but also the lowest (Tb = 32.4°C) Tb ever documented for wild koalas, suggesting that they are more heterothermic than previously recognized. This requires individuals to predict days of extreme Ta from overnight and early morning conditions, adjusting Tb regulation accordingly, and it has never been reported before for koalas. The large diel amplitude and low minimum Tb observed suggest that koalas at our study site are energetically and nutritionally compromised, likely due to their age. Behaviour (i.e. tree hugging and drinking water) was not effective in moderating Tb. These results indicate that Ta and koala Tb are strongly interconnected and reinforce the importance of climate projections for predicting the future persistence of koalas throughout their current distribution. Global climate models forecast that dry, hot weather will continue to escalate and drought events will increase in frequency, duration and severity. This is likely to push koalas and other arboreal folivores towards their thermal limit.

Tree frogs (Polypedates dennysi) landing on horizontal perches: the effects of perch diameter.

Secure landing is indispensable for both leaping animals and robotics. Tree frogs, renowned for their adhesive capabilities, can effectively jump across intricate 3D terrain and land safely. Compared with jumping, the mechanisms underlying their landing technique, particularly in arboreal environments, have remained largely unknown. In this study, we focused on the landing patterns of the tree frog Polypedates dennysi on horizontally placed perches, explicitly emphasizing the influence of perch diameters. Tree frogs demonstrated diverse landing postures, including the utilization of: (1) single front foot, (2) double front feet, (3) anterior bellies, (4) middle bellies, (5) posterior bellies, (6) single hind foot, or (5) double hind feet. Generally, tree frogs favoured bellies on slimmer targets but double front feet on large perches. Analysis of limb-trunk relationships revealed their adaptability to modify postures, including body positions and limb orientations, for successful landing. The variations in the initial landing postures affected the subsequent landing procedures and, consequently, the dynamics. As the initial contact position switched from front foot back to the hind foot, the stabilization time decreased at first, reaching a minimum in middle belly landings, and then increased again. The maximum vertical forces showed an inverse trend, whereas the maximum fore-aft forces continuously increased as the initial contact position switched. As the perch diameter increased, the time expended dropped, whereas the maximum impact force increased. These findings not only add to our understanding of frog landings but also highlight the necessity of considering perch diameters and landing styles when studying the biomechanics of arboreal locomotion.

Population Abundance and Density Estimates of Poorly Documented Near-Threatened Calabar Angwantibo (Arctocebus calabarensis) in Oban Hills Region.

Population abundance and density estimates play important roles in biodiversity conservation assessment and can lead to prioritization of conservation efforts, strategies, and management. The Calabar angwantibo (Arctocebus calabarensis) is a poorly studied, Near-Threatened nocturnal, arboreal mammal species occurring only in the lowland moist tropical rainforest blocks of southeastern Nigeria and southwestern Cameroon. Like other arboreal nocturnal mammals, there are gaps in knowledge of the distribution and abundance of this species, which may be facing population declines due to habitat loss and hunting. In this study, we investigated the abundance and density of A. calabarensis in the Oban Hills Region of Nigeria. We conducted systematic distance sampling survey along 32 transects in different habitats in a 1227 km of survey efforts. A total of 41 sightings of A. calabarensis were detected, resulting in an abundance of 7345 individuals (95% CI = 1.51-4.37) with an estimated density of 2.57 animals/km2. The estimated population abundance is 6515 individuals in closed-canopy forests and 830 individuals in secondary forests, with encounter rates of 0.52 individual/km2 and 0.60 individuals/km2 in the closed canopy and secondary forest habitats. The global estimates encounter rate of A. calabarensis across the habitat types is 0.33 individuals/km2 and population abundance of 4456 individuals. Our findings indicate that the A. calabarensis populations can adapt to low changes in forest habitat modifications resulting from increasing and widespread forest disturbance by human-dominated activity, which is giving way to forest clearance for agriculture cultivation and infrastructural development. Our findings help to fill a knowledge gap regarding this species and may help establish a baseline for future management, population monitoring, and conservation of the cryptic population of A. calabarensis in Cross-Sanaga Forests.

Elucidating the daily foraging activity pattern of Oecophylla smaragdina to minimize bite nuisances in Asia large agro-system plantations.

Oecophylla smaragdina F., the Asian weaver ant, is one of the oil palm plantation's (Elaeis guineensis) potential predators, for the invasive bagworm species Metisa plana Walker, but this ant is a nuisance species that irritates plantation workers with their sharp bites. Here we assess the foraging activities (FA) of O. smaragdina's major workers, identify its inactive times and the existence of supervision, a novelty for social insects. Between 2018 and 2022, the pattern of trunk foraging activity was used as a mitigation measure. The relationship between trunk FA and air temperature (AT), relative humidity (RH), air pressure (AP), and rainfall interception (RI) was also investigated. Our results showed that, O. smaragdina is a strictly diurnal ant species, has little to no crepuscular activity, and stopped foraging during darkness. Moreover, veteran bigger workers systematically acted as supervisors by monitoring trails, intercepting, and bringing back to nests smaller individuals during heat peaks. In relation to population size relative abundance, all colonies displayed greater intensity during the warmest daily periods with higher mean forager density among the bigger colony, regardless of the dry-rainy intervals corresponded to minimal activity from late scotophase to early photophase and showed a bimodal pattern. Thus, forager activity peaked between 1100-1530 h and 1745-1845 h, and an average two-fold daily sudden decrease in intensity between 1620 and 1650 h as a partial cut-off period (first report). Furthermore, foraging activity, AT, AP showed a significant positive correlation while RH was negative. Finally, we found that from the base palm trunks, defensive territorial layers extended to 5 m on average with different spatial configurations indicating greater foraging density within the first 2 m. Our study shows O. smaragdina daily low activity periods, before 1000 h, being the most suitable to avoid forager attacks to facilitate pruning and harvesting tasks.

Comparative kinetics of humans and non-human primates during vertical climbing.

Climbing represents a critical behavior in the context of primate evolution. However, anatomically modern human populations are considered ill-suited for climbing. This adaptation can be attributed to the evolution of striding bipedalism, redirecting anatomical traits away from efficient climbing. Although prior studies have speculated on the kinetic consequences of this anatomical reorganization, there is a lack of data on the force profiles of human climbers. This study utilized high-speed videography and force plate analysis to assess single limb forces during climbing from 44 human participants of varying climbing experience and compared these data with climbing data from eight species of non-human primates (anthropoids and strepsirrhines). Contrary to expectations, experience level had no significant effect on the magnitude of single limb forces in humans. Experienced climbers did, however, demonstrate a predictable relationship between center of mass position and peak normal forces, suggesting a better ability to modulate forces during climbing. Humans exhibited significantly higher peak propulsive forces in the hindlimb compared with the forelimb and greater hindlimb dominance overall compared with non-human primates. All species sampled demonstrated exclusively tensile forelimbs and predominantly compressive hindlimbs. Strepsirrhines exhibited a pull-push transition in normal forces, while anthropoid primates, including humans, did not. Climbing force profiles are remarkably stereotyped across humans, reflecting the universal mechanical demands of this form of locomotion. Extreme functional differentiation between forelimbs and hindlimbs in humans may help to explain the evolution of bipedalism in ancestrally climbing hominoids.

Effects of binocular cue availability on leaping performance in Cheirogaleus medius: implications for primate origins.

Multiple competing hypotheses attribute the evolution of the suite of traits that distinguish primates from their closest relatives, including forward-facing eyes, which create a wide field of binocular vision, to specific behavioral and ecological factors. The grasp-leaping hypothesis suggests that the evolution of these traits in basal primates was driven by the demands of a form of leaping locomotion unique to primates. Whether the grasp-leaping hypothesis provides a viable mechanism for the evolution of primates' forward-facing eyes remains untested. To determine whether grasp-leaping locomotion may have contributed to driving the evolution of primates' forward-facing eyes, the importance of vision within the binocular field for this type of leaping was evaluated experimentally in Cheirogaleus medius, one of the cheirogaleid primate species considered reasonable living analogs of the earliest primates. Availability of binocular visual cues was experimentally restricted using a head-mounted blinder that narrowed the binocular visual field without altering the total visual field. Animals altered their launch behavior, reduced their horizontal leap speed, and were significantly more likely to select paths that offered the shortest available leaps when their binocular field was restricted. Restriction of binocular cue availability also significantly increased the probability of adverse landings even when statistically controlling for potentially confounding variables such as leap distance, horizontal leap speed, learning effects, etc. These results suggest a functional mechanism by which selection for improved grasp-leaping could also have contributed to the evolution of forward-facing eyes in the earliest crown primates.

Petal-shaped femoral lobes facilitate gliding in orchid mantises.

To glide in forest canopies, arboreal vertebrates evolved various skin-derived aerodynamic structures, such as patagial membranes or webbing, but no comparable structure has been reported from wingless arboreal arthropods.1,2,3 Orchid mantises (Hymenopus coronatus) have been traditionally considered a textbook example of flower mimicry for ∼200 years due to their highly expanded, petal-shaped femoral lobes. However, the empirical evidence substantiating the petal-mimicry function of the femoral lobes has not been entirely conclusive.4,5,6 Observational and experimental evidence suggests that these lobes do not contribute to flower mimicry for luring pollinators6,7 and likely serve other functions.7,8 After observing their aerial escape initiated with active jumping, we hypothesized that orchid mantises can glide and that their femoral lobes are used for gliding. Through behavioral investigations and morphological analyses, we show that orchid mantis nymphs are excellent gliders, exhibiting the shallowest gliding trajectories observed in terrestrial invertebrates.9,10,11,12,13 The lobe extensions on their femoral segments are cambered airfoils, which increase the mantis projected area by ∼36% and play a vital role in the aerodynamic underpinning of the observed gliding. Despite a 165-fold increase in body mass throughout ontogeny, older female mantis nymphs maintained a persistent gliding capability. We further showed a notable 40%-56% reduction in wing loading attributed to the positive size allometry of these lobes, indicating a clear promotion of gliding throughout ontogeny. This is the first documentation of gliding-adapted "leg wings" in a wingless arthropod. The evolution of such structures is potentially common among arboreal arthropods and demands a systematic re-examination.

Gut Microbiome Profiling of the Endangered Southern Greater Glider (Petauroides volans) after the 2019-2020 Australian Megafire.

Studying the gut microbiome can provide valuable insights into animal health and inform the conservation management of threatened wildlife. Gut microbiota play important roles in regulating mammalian host physiology, including digestion, energy metabolism and immunity. Dysbiosis can impair such physiological processes and compromise host health, so it is essential that the gut microbiome be considered in conservation planning. The southern greater glider (Petauroides volans) is an endangered arboreal marsupial that faced widespread habitat fragmentation and population declines following the 2019-2020 Australian bushfire season. This study details baseline data on the gut microbiome of this species. The V3-V4 region of the 16S rRNA gene was amplified from scats collected from individuals inhabiting burnt and unburnt sites across southeastern Australia and sequenced to determine bacterial community composition. Southern greater glider gut microbiomes were characterised by high relative abundances of Firmicutes and Bacteroidota, which is consistent with that reported for other marsupial herbivores. Significant differences in gut microbial diversity and community structure were detected among individuals from different geographic locations. Certain microbiota and functional orthologues were also found to be significantly differentially abundant between locations. The role of wildfire in shaping southern greater glider gut microbiomes was shown, with some significant differences in the diversity and abundance of microbiota detected between burnt and unburnt sites. Overall, this study details the first data on greater glider (Petauroides) gut microbiomes, laying the foundation for future studies to further explore relationships between microbial community structure, environmental stressors and host health.

A new electric-blue tarantula species of the genus Chilobrachys Karsh, 1892 from Thailand (Araneae, Mygalomorphae, Theraphosidae).

The enchanting phenomenon of blue coloration in animals arises from the fact that blue is one of the rarest colors found in nature, and it is a structural color that is produced by the arrangement of biological photonic nanostructures, rather than pigments. This unique coloration has evolved independently in many different species, adding to the fascination and diversity of coloration patterns in the animal kingdom. This study describes a new species of Chilobrachys Karsch, 1892 from southern Thailand that exhibits a blue-violet hue resembling the color of electrical sparks. Photographic illustrations, a morphological description, and the natural habitat of the new species are given. The diagnosis, palpal-bulb structures, spermathecae, and stridulatory organ morphology of related species are discussed.

Tree species identity, canopy structure and prey availability differentially affect canopy spider diversity and trophic composition.

Forest canopies maintain a high proportion of arthropod diversity. The drivers that structure these communities, however, are poorly understood. Therefore, integrative research connecting tree species identity and environmental stand properties with taxonomic and functional community composition of canopy arthropods is required. In this study, we investigated how the taxonomic, functional and trophic composition of arboreal spider communities is affected by tree species composition and associated differences in canopy structure and prey availability in temperate forests. We sampled canopy spiders as well as their potential prey using insecticidal fogging in monospecific and mixed stands of native European beech, native Norway spruce and non-native Douglas fir. Trophic metrics were obtained from stable isotope analysis and structural canopy properties were assessed with mobile laser scanning. Monospecific native spruce stands promoted local canopy spider abundance and diversity, but native beech and beech-conifer mixtures had the highest diversity at landscape scale. Spider community composition differed between monospecific stands, with broadleaf-conifer mixtures mitigating these differences. Irrespective of tree species identity, spider abundance, taxonomic diversity, functional richness and isotopic richness increased in structurally heterogeneous canopies with high prey abundances, but functional evenness and trophic divergence decreased. Our study shows that canopy spiders are differentially affected by tree species identity, canopy structure and prey availability. Broadleaf-conifer mixtures mitigated negative effects of (non-native) conifers, but positive mixture effects were only evident at the landscape scale. Structurally heterogeneous canopies promoted the dominance of only specific trait clusters. This indicates that intermediate heterogeneity might result in high stability of ecological communities.

Biomechanics and the origins of human bipedal walking: The last 50 years.

Motion analysis, as applied to evolutionary biomechanics, has experienced its own evolution over the last 50 years. Here we review how an ever-increasing fossil record, together with continuing advancements in biomechanics techniques, have shaped our understanding of the origin of upright bipedal walking. The original, and long-established hypothesis held by Lamarck (1809), Darwin (1859) and Keith (1934), amongst others, maintained that bipedality originated in an arboreal context. However, the first field studies of gorilla and chimpanzees from the 1960's, highlighted their so-called 'knucklewalking' quadrupedalism, leading scientists to assume, semi-automatically, that knucklewalking must have been the precursor to bipedality. It would not be until the discovery of skeletons of early human relatives Australopithecus afarensis and Australopithecus prometheus, and the inclusion of methods of analysis from computer science, biomechanics, sports science and medicine, that the knucklewalking hypothesis would be most robustly challenged. Their short, but human-like lower limbs and human-like hand indicated that knucklewalking was not part of our ancestral locomotor repertoire. Rather, most current research in evolutionary biomechanics agrees it was a combination of climbing and bipedalism, both in an arboreal context, which facilitated upright, terrestrial, bipedal walking over short distances.

Spatiotemporal walking gait kinematics of semi-arboreal red pandas (Ailurus fulgens).

Semi-arboreal mammals must routinely cope with the differing biomechanical challenges of terrestrial versus arboreal locomotion; however, it is not clear to what extent semi-arboreal mammals adjust footfall patterns when moving on different substrates. We opportunistically filmed quadrupedal locomotion (n = 132 walking strides) of semi-arboreal red pandas (Ailurus fulgens; n = 3) housed at Cleveland Metroparks Zoo and examined the effects of substrate type on spatiotemporal gait kinematic variables using linear mixed models. We further investigated the effects of substrate diameter and orientation on arboreal gait kinematics. Red pandas exclusively used lateral sequence (LS) gaits and most frequently utilized LS lateral couplet gaits across terrestrial and arboreal substrates. Red pandas moved significantly slower (p < 0.001), and controlling for speed, had significantly greater relative stride length (p < 0.001), mean stride duration (p = 0.002), mean duty factor (p < 0.001), and mean number of supporting limbs (p < 0.001) during arboreal locomotion. Arboreal strides on inclined substrates were characterized by significantly faster relative speeds and increased limb phase values compared with those horizontal and declined substrates. These kinematics adjustments help to reduce substrate oscillations thereby promoting stability on potentially precarious arboreal substrates. Red panda limb phase values are similar to those of (primarily terrestrial) Carnivora examined to date. Despite the similarity in footfall patterns during arboreal and terrestrial locomotion, flexibility in other kinematic variables is important for semi-arboreal red pandas that must navigate disparate biomechanical challenges inherent to arboreal versus terrestrial locomotion.

Locomotor characteristics of the ground-walking chameleon Brookesia superciliaris.

Understanding the locomotor characteristics of early diverging ground-walking chameleons (members of the genera Brookesia, Rhampholeon, Palleon, and Rieppeleon) can help to explain how their unique morphology is adapted to fit their environment and mode of life. However, nearly all quantitative studies of chameleon locomotion thus far have focused on the larger "true arboreal" chameleons. We investigated kinematics and spatiotemporal gait characteristics of the Brown Leaf Chameleon (Brookesia superciliaris) on different substrates and compared them with true arboreal chameleons, nonchameleon lizards, and other small arboreal animals. Brookesia exhibits a combination of locomotor traits, some of which are traditionally arboreal, others more terrestrial, and a few that are very unusual. Like other chameleons, Brookesia moved more slowly on narrow dowels than on broad planks (simulating arboreal and terrestrial substrates, respectively), and its speed was primarily regulated by stride frequency rather than stride length. While Brookesia exhibits the traditionally arboreal trait of a high degree of humeral protraction at the beginning of stance, unlike most arboreal tetrapods, it uses smaller shoulder and hip excursions on narrower substrates, possibly reflecting its more terrestrial habits. When moving at very slow speeds, Brookesia often adopts an unusual footfall pattern, lateral-sequence lateral-couplets. Because Brookesia is a member of one of the earliest-diverging groups of chameleons, its locomotion may provide a good model for an intermediate stage in the evolution of arboreal chameleons. Thus, the transition to a fully arboreal way of life in "true arboreal" chameleons may have involved changes in spatiotemporal and kinematic characteristics as well as morphology.

Diagonal-couplet gaits on discontinuous supports in Japanese macaques and implications for the adaptive significance of the diagonal-sequence, diagonal-couplet gait of primates.

OBJECTIVES: Diagonal-sequence, diagonal-couplet (DSDC) gaits have been proposed as an adaptation to travel on discontinuously arranged arboreal branches. Only a few studies have examined primate gait adjustment to support discontinuity. We analyzed the gaits of Japanese macaques walking on the "ground" and two discontinuous conditions, "circle" and "point," to better understand the advantages of DSDC gaits on discontinuous supports. MATERIALS AND METHODS: Seventy-eight vertical posts, each with a circular upper surface, were arranged in four rows at a spacing of 200 mm. The diameter of the circular upper surface was 150 mm ("circle condition") or 50 mm ("point condition"). We calculated the limb phase, duty factor, and time interval from hindlimb touchdown to ipsilateral forelimb liftoff. The supports the fore- and hindlimbs landed on during walking were identified in the circle and point condition. RESULTS: The macaques predominantly used DSDC gaits in the ground and circle conditions and lateral-sequence, diagonal-couplet (LSDC) gaits in the point condition. The macaques usually placed their hindlimbs on the same supports as their ipsilateral forelimbs during the gait cycle. DISCUSSION: Japanese macaques overlapped the ipsilateral fore- and hindlimb stance phase in all DSDC and some LSDC gaits to proximate the ipsilateral limbs on the discontinuous support, allowing the forelimb to guide the hindlimb placement to the support. The overlap duration of the ipsilateral limb stance phases may be extended by DSDC gaits longer than by LSDC gaits, allowing for a direct pass of the support being held by the prehensile hand to the prehensile foot.

On the noxious black Amazonian scorpion, Tityus obscurus (Scorpiones, Buthidae): Taxonomic notes, biology, medical importance and envenoming treatment.

Tityus obscurus has caused mild, moderate and severe accidents of medical relevance in the eastern Brazilian Amazon and French Guiana. Tityus obscurus has sexual dimorphism although males and females have uniform black coloration. In the Amazon, one of the habitats of this scorpion is seasonally flooded forests (igapós and várzeas). However, most stings occur in terra firme forest areas (non-flooded region), where most rural communities are located. Adults and children stung by T. obscurus may experience an "electric shock" sensation for more than 30 h after the sting. Our data shows that people inhabiting remote forest areas, including rubber tappers, fishermen and indigenous people, with no access to anti-scorpion serum, use parts of native plants, such as seeds and leaves, against pain and vomiting caused by scorpion stings. Although there is a technical effort to produce and distribute antivenoms in the Amazon, many cases of scorpion stings are geographically unpredictable in this region, due to the lack of detailed knowledge of the natural distribution of these animals. In this manuscript, we compile information on the natural history of T. obscurus and the impact of its envenoming on human health. We identify the natural sites that host this scorpion in the Amazon, in order to warn about the risk of human envenoming. The use of specific antivenom serum is the recommended treatment for accidents involving venomous animals. However, atypical symptoms not neutralized by the available commercial antivenom are reported in the Amazon region. Facing this scenario, we present some challenges to the study of venomous animals in the Amazon rainforest and possible experimental bottlenecks and perspectives for establishing a method aimed at producing an efficient antivenom.