Extinction Research Articles

Multi-habitat landscapes are more diverse and stable with improved function

Conservation, restoration and land management are increasingly implemented at landscape scales1,2. However, because species interaction data are typically habitat- and/or guild-specific, exactly how those interactions connect habitats and affect the stability and function of communities at landscape scales remains poorly understood. We combine multi-guild species interaction data (plant–pollinator and three plant–herbivore–parasitoid communities, collected from landscapes with one, two or three habitats), a field experiment and a modelling approach to show that multi-habitat landscapes support higher species and interaction evenness, more complementary species interactions and more consistent robustness to species loss. These emergent network properties drive improved pollination success in landscapes with more habitats and are not explained by simply summing component habitat webs. Linking landscape composition, through community structure, to ecosystem function, highlights mechanisms by which several contiguous habitats can support landscape-scale ecosystem services.

A comparison of wild boar and domestic pig microbiota does not reveal a loss of microbial species but an increase in alpha diversity and opportunistic genera in domestic pigs.

The microbiome of pigs plays a crucial role in shaping host physiology and health. This study sought to identify if domestication and current rearing practices have resulted in a loss of co-evolved bacterial species by comparing the microbiome of wild boar and conventionally raised pigs. It provides a comparison of domestic and wild pigs with the largest sample sizes and is the first to examine wild boars from multiple sites and continents. We were able to identify core microbiome members that were shared between wild and domestic populations, and on the contrary to expectation, few microbes were identified to be lost from wild boar. Nevertheless, the microbiome of wild boars had a lower abundance of important pathogenic genera and was distinct from domestic pigs. The differences in the microbial composition may identify an opportunity to shift the microbial community of domestic pigs towards that of wild boar with the intent to reduce pathogen load.

Multidimensional aspects of riverine biodiversity can vary in response to nutrient pollution and environmental dynamics across climatic watersheds

The concurrent impact of anthropogenic and bioclimatic factors on biodiversity is a key focus in macroecological and biogeographical considerations in conservation programs within riverine ecosystems. However, there is still a lack of understanding about how multidimensional alpha and beta diversity measures respond to anthropogenic and bioclimatic drivers. Here, we assess the variations in taxonomic, phylogenetic, and functional alpha and beta diversity of riverine macroinvertebrate communities across different watersheds in China. Our results show significant declines in most facets of alpha diversity across watersheds with low environmental heterogeneity, reflecting the loss of species with unique traits and evolutionary legacies. Both functional and phylogenetic beta-diversity values reveal a decreasing pattern along low heterogeneity environments, whereas taxonomic beta-diversity shows a contrasting pattern, which highlights the influence of microhabitat variation. Moreover, our findings identify nutrient levels, organic matter, water quality indicators, climatic variation, and geographic and habitat characteristics as key determinants of diversity patterns that are indicative of broader water pollution challenges. These factors jointly influence functional and phylogenetic alpha diversity and contribute to spatial homogenization, which is reflected in decreased functional and phylogenetic beta diversity. These trends highlight the complex interactions of chemical and physical factors in shaping biodiversity characteristics across watersheds. Based on the null model, macroinvertebrate communities primarily show random patterns, whereas clustering and overdispersion were sporadically observed in specific communities. We propose that conservation and restoration efforts should be aimed at enhancing aquatic biomes by managing extreme environmental conditions and amplifying spatial spillover, thereby supporting the intrinsic dynamics within natural metasystems and thus preserving the multidimensional aspects of biodiversity.

Declines and shifts in morphological diversity of ciscoes (Coregonus spp.) in lakes Huron and Michigan, 1917–2019

Ciscoes ( Coregonus spp .) were historically abundant and ecologically important in Laurentian Great Lakes ecosystems. Despite well-documented declines in their abundance and taxonomic diversity, declines in morphological diversity remain understudied. This knowledge gap is especially pertinent for lakes Michigan and Huron, which have each lost six of eight historical species. Improved understanding of historical and contemporary morphological diversity of Great Lakes ciscoes can inform ongoing restoration efforts and further elucidate the factors that contributed to declines. Our goal was to characterize shifts in morphological diversity of ciscoes in lakes Michigan and Huron over a century (1917–2019). We analyzed size-corrected morphometric and meristic measurements from three periods: Early (1917–1923), Middle (1950–1972), and Contemporary (2015–2019). We then identified morphologically distinct clusters while remaining agnostic to species identifications. We found that morphological diversity and the number of distinct clusters declined over time. We then leveraged species identifications to highlight key species losses and examine morphological shifts among extant species. Our findings provide insights into the historical and contemporary morphological diversity of ciscoes and will inform restoration efforts.

Predicting the climatic suitability of non-native drought resistant trees in the face of desertification – A case study with Argania spinosa in the Iberian Peninsula

Climate change is driving a poleward shift in the optimal distributions of terrestrial organisms, including trees. Consequently, trees are expected to decrease in climatically unfavourable areas as their optimal climatic conditions shift poleward. This is the case of Mediterranean High Nature Value agroforestry systems in Iberian Peninsula, dominated by holm oaks (Quercus rotundifolia) and cork oaks (Quercus suber), which are expected to shift their future distribution northward. Failure to keep pace with climate warming poses a heightened risk of extinction for these tree species, as well as the loss of crucial ecosystem services they provide. A similar situation is found for argan trees (Argania spinosa) in the southwestern region of Morocco, where it also supports an agroforestry system. The optimum climate for these trees is also shifting northward, toward the Iberian Peninsula. As the argan tree thrives in more arid conditions with irregular precipitation, the future climatic conditions in the Iberian Peninsula may become favourable for the persistence of this tree. In light of this situation, the assisted colonization of the argan tree could potentially contribute to protecting and preserving the tree-associated ecosystem services in Iberian Peninsula. We conducted climate suitability modelling using maximum entropy approach, for both the current and future timeframes, for North of Morocco and Algeria (native range) and the whole Iberian Peninsula (non-native range). Accordingly, there appears to be a significant area with highly suitable climatic conditions (>80 %) for argan tree occurrence, covering approximately 6.7 % of the territory, over 38,000 km2. This area is projected to increase significantly in the future, covering 9–22 % of the territory, or about 55,000 and 127,000 km2. With this study, we aim to contribute to the discussion on the benefits of assisted colonization of argan trees into Iberian Peninsula, as well as potential drawbacks such as the risk of this species becoming invasive.

First record of Nicobium LeConte (Coleoptera: Ptinidae: Anobiinae) from Baltic amber with the description of a new extinct species

First record of Nicobium LeConte (Coleoptera: Ptinidae: Anobiinae) from Baltic amber with the description of a new extinct species

Effect of Climate Change on Wildlife

Climate change is a global catastrophe that disrupts the balance of ecosystem by altering the climatic measures. Human being are not the only living species on earth that is affected by climate change. All the inhabitants on Earth are dependent on suitable living conditions for their survival. All human and non-human species on Earth either directly or indirectly relying on each other. Wildlife is the key indicator of climatic changes in the environment as they are part of various biological and ecological cycles in the atmosphere. Over the century, the atmospheric temperature has increased around 1.1°C. Changes in climatic conditions is affecting the terrestrial and aquatic biomes in plenty of ways. Limiting basic living conditions of animals by destruction of their natural habitation and its transformation into urban lands which intensifies the human-wildlife interactions. Migration of temperature sensitive species to the areas of higher altitude. High temperatures have increased the occurrence of wild-land fires, floods and droughts five times more than past 50 years. Animals naturally respond to altering climatic conditions by exhibiting changes in their general and reproductive behavior, growth patterns, increased zoonotic diseases. All these above cited effect put them to the status of endangered species and ultimately to the extinction. Strategic approaches i.e., protection, management, planning and evaluation of natural biomes to conserve the Earth’s biodiversity must be opted to avoid the extinction of wild species.

The rise and fall of notoungulates: How Andean uplift, available land area, competition, and depredation driven its diversification dynamics

Unraveling the biotic and abiotic drivers likely influencing clades’ diversification dynamics (differential speciation and extinction rates) is crucial for understanding life on Earth. Here, we present a comprehensive analysis of the diversification dynamics of notoungulates (Mammalia: Notoungulata), the most diverse and widespread Cenozoic herbivore mammals that evolved in South America (SA) but are now entirely extinct. Employing fossil occurrences restricted to the southern part of the SA and a Bayesian framework, we examined the historical speciation and extinction rates across all notoungulates, suborders, and three body size categories and tested whether these dynamics could be driven by biotic (e.g., diversity dependence, competition) and abiotic (e.g., Andean uplift and temperature changes) factors. Our findings reveal significant variability in diversification rates over time and groups driven by biotic and abiotic factors. We observed an increase in notoungulate speciation rates correlated with lower group self-diversity, likely related to limited environmental productivity and more extensive emerged continental areas that can provide increased environmental and ecological heterogeneity. In contrast, elevated extinction rates were correlated with intensified Andean uplift events, which can trigger landscape modifications and the arrival of placental carnivores after the Great American Biotic Interchange, probably due to notoungulate vulnerability to novel predation pressures. Furthermore, sparassodont diversity appears to increase speciation and extinction rates of notoungulates, although the direct mechanism relating them remains uncertain. The heterogeneity in the observed patterns of speciation and extinction across distinct size categories and taxonomic clades provides valuable perspectives on how ancient global and regional changes impacted the diversification dynamics of mammals and underscores the intricate interplay between environmental changes and biological interactions in shaping the evolution of life on Earth.

Climate change's influence on Chelydra serpentina's global and Chinese distribution and invasion: A MaxEnt model-based prediction

Chelydra serpentina (Linnaeus, 1758) is native to North America, but has been introduced to numerous nations and is now globally spread. It is extremely adaptive, grow quickly, and its biological population is steadily increasing as a result of the development of aquaculture technology. Given that Chelydra serpentina has already been found alive in the natural ecosystems of China, its proliferation poses a possible threat of invasion. Using the global distribution data of the species in the current environment, a study was carried out to forecast the distribution trend of Chelydra serpentina under future climate circumstances. The study compared the changes in the distribution area under current climatic circumstances and the tendency of proliferation using 19 bioclimatic factors and the ecological niche model Maxent. Using the significance index, the study also examined the size of the appropriate region and the influencing factors to estimate the danger of Chelydra serpentina invasion better quantitatively. In our research, we hypothesized that forthcoming climate change will affect the geographical distribution of Chelydra serpentina. The study results showed that, even in high-intensity environments, the appropriate area for Chelydra serpentina will steadily increase in the future climate. The extent of their suitable habitat might expand (the highly suitable area: 7.42*105 km2 <China>; 2.13*107 km2 <Global>) in contrast to the distribution area of Chelydra serpentina under the existing climate (highly suitable area: 6.01*105 km2 <China>; 8.48*106 km2 <Global>). The research findings indicate that the range of the habitat area predicted to proliferate (the highly suitable area of 6.31*105 km2 <China>; 1.3 *107 km2 <Global>) even in high-intensity environments, albeit at a slower rate than in the low-intensity environment model. The habitat will initially be concentrated in warmer regions before progressively expanding into the colder northern climate. This implies that Chelydra serpentina will be able to more easily adjust to future climates and spread outward over time from its concentrated home. Nonetheless, there is a chance of an invasion due to the rise in Chelydra serpentina populations. Upon establishing a regular reproductive presence in the Chinese waterways they inhabit, these turtles will engage in fierce competition with indigenous species for survival, posing a threat to the environment and potentially resulting in the extinction of some local species.

Enhanced Catalytic Performance of Palladium‐Based Catalysts Modified With the Dibenzofuran Ligand for Acetylene Hydrochlorination

ABSTRACTA new palladium‐based catalyst system modified with dibenzofuran (DBF) was developed for acetylene hydrochlorination. The optimal Pd‐DBF/SAC catalyst with the 0.5 wt% Pd loading and the 15 wt% DBF loading exhibits an elevated performance of 99.9% acetylene conversion and 99.9% vinyl chloride selectivity for more than 400 h. Characterization analysis and density functional theory (DFT) simulations revealed that the presence of oxygen‐containing DBF species of the Pd‐DBF/SAC catalyst prevents the reduction and loss of Pd species, inhibits the carbon deposition and enhances the HCl adsorbability, resulting in superior catalytic activity and stability for acetylene hydrochlorination.

Effects of online tours at the zoo and natural history museum on interest in extant and extinct animals

ABSTRACT During the Corona pandemic, many extracurricular learning sites with a biological focus, such as zoos and natural history museums, were closed. In order to offer students the opportunity to visit these learning sites even under pandemic conditions, online live tours were conducted at the Senckenberg Natural History Museum and the Frankfurt Zoo. To investigate the effects of this educational format on students’ individual interest in extinct prehistoric and extant animals, they were surveyed in writing in a pre/post/follow-up design. The results of the study show a mixed picture. While online tours at the zoo had very little effect on interest in extant animals, significant increases in interest in extinct animals were shown immediately after a tour at the Natural History Museum. But even these effects were not sustained, as follow-up tests demonstrated. Apparently, it is very difficult to maintain interest in animals over a longer period of time through online guided tours. Possible reasons for this are the lack of an authentic experience, the lack of a special atmosphere in the real extracurricular places of learning and the lack of a personal, tangible connection to the exhibits and live animals.

Synergistic Electrocatalyst-Cathode Architecture for Stable Long-Term Cycling Lithium-Sulfur Batteries

Lithium-sulfur (Li-S) batteries are a promising candidate for next-generation energy storage owing to the high theoretical capacity of sulfur (1,675 mAh g−1). However, the intrinsically low electrical conductivity of sulfur and complex multistep electrolyte-mediated redox reactions involving soluble lithium polysulfide intermediates engender critical challenges toward practical realization. Specifically, migration and diffusion of higher-order lithium polysulfides provokes continuous loss of active sulfur species, yielding premature capacity fade. Electrochemical kinetics also remain sluggish due to the insulating nature of sulfur cathodes, which require engineering designs to accelerate charge transfer.Rational morphological and compositional cathode tuning represents a compelling strategy for addressing fundamental Li-S limitations. Herein, we develop an extended cathode architecture composed of a porous carbon nanotube network decorated with homogenously dispersed nanocatalysts. Electron microscopy and spectroscopy analysis verify platinum group metals are well-incorporated both within internal channels and external surface sites of conductive carbon nanotubes. The composite framework affords multifaceted functionality arising from synergistic chemical and structural attributes of components. Nanocatalyst sites demonstrate a pronounced chemical affinity toward soluble polysulfide intermediates, effectively localizing them within cathode, minimizing diffusional losses toward the anode. This anchoring phenomenon is complemented by the inherent microporosity of the high-surface-area nanotube network, further obstructing polysulfide migration through a confinement effects. Concurrently, noble metal nanoparticles facilitate the redox conversion of trapped higher-order polysulfides into solid Li2S alleviating the precipitation of electrically insulating discharge products. The excellent electrical conductivity of CNTs ensures efficient charge transport to all incorporated sulfur active materials, further maximizing reversible utilization.As a result of complementary polysulfide confinement and electrocatalytic conversion functionalities, Li-S coin cells exhibit enhanced reversible capacities exceeding 900 mAh g−1 for over 500 cycles at 0.558 A g−1. Notably, over 500 cycles, minimal capacity decay of 0.018% per cycle and 92% retention of the initial capacity are obtained at moderate sulfur loadings highlighting the exceptional cycling stability enabled by engineered cathodes. Outstanding rate performance is also demonstrated with the delivery of 854 mAh g−1 capacity at a very high current density of 1.675 A g−1. Our rationally designed cathode architecture provides critical mechanistic insight toward addressing fundamental bottlenecks to progress Li-S technologies.

A history of research on the cave lion Panthera spelaea (Goldfuss, 1810)

In 1810, G.A. Goldfuss was the first to identify the bones of a cave lion discovered in the Zoolithenhöhle cave (Germany), naming it Felis spelaea. But it was prehistoric man who first described it in numerous parietal and movable representations. Since the beginning of the 19th century, scientific knowledge of the cave lion Panthera (Leo) spelaea has progressed steadily, establishing its leonine character. Numerous discoveries led to paleontological studies of deposits throughout Eurasia, often in caves and linked to prehistoric sites. In the 20th century, this research benefited from the emergence of new dating methods, the development of palynology and the isotopic biochemistry of collagen. As the species' range became better defined, it expanded to include the whole of Eurasia and even North America. Finally, the 21st century is marked by the development of paleogenetics and the multiplication of synthetic studies, in many countries, while benefiting from a diffusion largely facilitated by Internet exchanges and the use of English. Phylogeny of the Felidae and understanding of the origins of Panthera spelaea are progressing rapidly. Today's knowledge makes it possible to envisage a true paleobiology of this extinct species.

The last of their kind: Is the genus Scutiger (Anura: Megophryidae) a relict element of the paleo-Transhimalaya biota?

The orographic evolution of the Himalaya-Tibet Mountain system continues to be a subject of controversy, leading to considerable uncertainty regarding the environment and surface elevation of the Tibetan Plateau during the Cenozoic era. As many geoscientific (but not paleontological) studies suggest, elevations close to modern heights exist in vast areas of Tibet since at least the late Paleogene, implicating the presence of large-scale alpine environments for more than 30 million years. To explore a recently proposed alternative model that assumes a warm temperate environment across paleo-Tibet, we carried out a phylogeographic survey using genomic analyses of samples covering the range of endemic lazy toads (Scutiger) across the Himalaya-Tibet orogen. We identified two main clades, with several, geographically distinct subclades. The long temporal gap between the stem and crown age of Scutiger may suggest high extinction rates. Diversification within the crown group, depending on the calibration, occurred either from the Mid-Miocene or Late-Miocene and continued until the Holocene. The present-day Himalayan Scutiger fauna could have evolved from lineages that existed on the southern edges of the paleo-Tibetan area (the Transhimalaya = Gangdese Shan), while extant species living on the eastern edge of the Plateau originated probably from the eastern edges of northern parts of the ancestral Tibetan area (Hoh Xil, Tanggula Shan). Based on the Mid-Miocene divergence time estimation and ancestral area reconstruction, we propose that uplift-associated aridification of a warm temperate Miocene-Tibet, coupled with high extirpation rates of ancestral populations, and species range shifts along drainage systems and epigenetic transverse valleys of the rising mountains, is a plausible scenario explaining the phylogenetic structure of Scutiger. This hypothesis aligns with the fossil record but conflicts with geoscientific concepts of high elevated Tibetan Plateau since the late Paleogene. Considering a Late-Miocene/Pliocene divergence time, an alternative scenario of dispersal from SE Asia into the East, Central, and West Himalaya cannot be excluded, although essential evolutionary and biogeographic aspects remain unresolved within this model.

A high-precision and near-zero residue laser-controlled gel propellant

Micro-nano satellites, with their advantages of small size, low power consumption, short development cycles, and capability for formation flying and networking, play a significant role in scientific research, national defense, and commercial applications. However, currently developed micro-nano satellites globally possess very limited maneuverability and lack effective attitude and orbit propulsion control. Solid propellants can offer some advantages such as high energy density and low cost, and they are extensively used in micro-and nano satellite propulsion systems. However, most of these propellants exhibit poor controllability and produce massive amounts of residual by-products. Laser-controlled gel propellants have been confirmed to be the most effective solution to address these issues in this study. The present study exhibits the preparation of ADN-based laser-controlled gel propellants using the freeze–thaw method and their controllable combustion characteristics under laser irradiation. The results show that the ignition delay time of gel propellants decreases from 93.0 ms to 34.6 ms, the extinction delay time is stable at around 2 ms, and the average burning rate increases from 0.6 mm/s to 1.5 mm/s under continuous laser irradiation with the power density ranging from 0.6 to 1.3 W/mm2. The average utilization rate of gel propellant is as high as 99.2 %. Upon testing, the residual solid matter was identified as unreacted propellant that had not been irradiated by the laser. Laser-controlled gel propellants represent a new type of energetic material that can be modulated to control its ignition, extinction, and burning rate. These capabilities overcome the challenges associated with the inability of traditional chemical propellants to extinguish and restart, thereby fulfilling the propulsion system requirements of micro-nano satellites.

The practices of care: extinction and de-colonization in the natural history museum

ABSTRACT The practices of care of extinct animal specimens and other materials in natural history museums are many and varied. This article focuses upon two extinct animal examples from the Berlin Museum of Natural History (MfN), the quagga and the thylacine, to present critiques of historical care and argue for Indigenous led alternatives. These critiques and arguments are organized via the organizing headings of isolation, preservation and revolution. While the dark histories of museums as active purchasers and collectors of ancestral remains and creators of markets for scarce forms of life are sometimes acknowledged, it is not a history that has been critically connected to normative practices of ‘isolation’ and ‘preservation’. Indeed, such practices are often heedless of the ongoing demand to recognize Indigenous continuities and are unresponsive to calls for relations that figure the museum ‘materials’ as simultaneously understood as colonial/scientific events and entities that are lively and capable of producing diverse effects. Such understandings emerge from engagement with diverse critiques including those arising from Indigenous writings. One pathway to reimagine the museum and practice an aware care may be to consider the simultaneous times at play within such institutions and the decolonizing possibilities of organizing practices beyond a single linear time.

Resource limitation of compensatory responses in ecosystem processes after biodiversity loss

Abstract Biodiversity loss may result in the decline in important ecosystem processes. The effect of biodiversity loss on ecosystem functioning is determined by the functional contribution of the species lost and the compensatory responses of the remaining species. It is unknown to what extent the strength of the compensatory response of the remaining species depends on resources availability. Here we evaluate how the primary production of an assemblage of salt marsh plants responds to a realistic sequence of species loss in an 7‐year experiment, with and without the addition of fertiliser. We found near‐full compensation of progressive species loss in gross community primary production by the extinction‐resistant species with fertiliser as long as one species (Triglochin maritima) remained. Without fertiliser, at least four species, including the particularly abundant species Plantago maritima, were needed to maintain gross community primary production. These results suggest that the magnitude of the compensation by extirpation‐resistant species for the decline in ecosystem processes associated with progressive biodiversity loss depends on the resource context, and that compensation after the loss of plant species can be accelerated by increasing resource availability. Ultimately, full compensation appears to be limited by the presence and abundance of species in the remaining community that possess traits that allow them to compensate for the species lost. Synthesis and applications: These findings suggests that the conclusions of a large body of biodiversity‐ecosystem experiments cannot be used for informing the management of natural systems because they do not simulate realistic extinction sequences and therefore cannot quantify the potential for compensation of ecosystem services in the real world.

Existing Conditions of Gastropod Communities in Areas Affected by Nickel Mining Overburden in the Mangrove Ecosystem of Dawi-Dawi, Southeast Sulawesi

ARTICLE HIGLIGHTS- Nickel mining activities significantly impacted the ecological integrity of the Pomalaa coastal area in Southeast Sulawesi, particularly in the mangrove ecosystem.- The exposure of overburden waste in the mangrove ecosystem has led to the loss of important gastropod species and a decline in population of surviving species- The low population of gastropod species in nickel mining impact areas indicates extensive environmental damage caused by these activities.ABSTRACTGastropod resources in the Dawi-Dawi mangrove ecosystem, Southeast Sulawesi are greatly influenced by the input of overburden waste (sediment) from nickel mining activities. This condition has been going on for the last 2 decades and has degraded the habitat and structure of the gastropod community. The upstream connectivity (the existing nickel mining area) and the Dawi-Dawi River estuary mean that the mangrove forest (estuary) in this area is continuously affected by (massive) overburden runoff. This research was carried out in June-August in the mangrove ecosystem of Dawi-Dawi Village, Southeast Sulawesi Province. This research aims to determine the existing condition of mangrove gastropods affected by overburden. This research began by conducting initial observations in the field, to identify mangrove ecosystems affected by overburden. research stations were determined using a purposive sampling technique (targeted) and sampling gastropods using a simple random sampling method. The ecological index of the mangrove gastropod community affected by overburden shows a tendency for a medium diversity index (H'=1.81), low species richness (R=1.42), high evenness (E=1.12), and no dominance of certain species (C=0.19). The gastropod species found are typical types that make up the mangrove fauna, namely Terebralia sulcata, Terebralia palustris, Faunus ater, Telescopium telescopium, Hebra nigra, and several taxa (genus) of climbing Littoraria snails (periwinkle) which are found in the roots, stems and leaves of mangroves. The abundance of gastropods obtained was also very low, namely around 0-12 Ind./m2. At some points (rarely) schools of small snails of the type T. sulcata (5-21 Ind./m2) are sometimes found. This research shows de facto that overburden waste eliminates (survival) or reduces the diversity and richness of gastropod species (ecological index) in the mangrove ecosystem of Dawi-Dawi.

Femora nutrient foramina and aerobic capacity in giant extinct xenarthrans.

Nutrient foramina are small openings in the periosteal surface of the mid-shaft region of long bones that traverse the cortical layer and reach the medullary cavity. They are important for the delivery of nutrients and oxygen to bone tissue and are crucial for the repair and remodeling of bones over time. The nutrient foramina in the femur's diaphysis are related to the energetic needs of the femur and have been shown to be related to the maximum metabolic rate (MMR) of taxa. Here, we investigate the relationship between nutrient foramen size and body mass as a proxy to the aerobic capacity of taxa in living and extinct xenarthrans, including living sloths, anteaters, and armadillos, as well as extinct xenarthrans such as glyptodonts, pampatheres, and ground sloths. Seventy femora were sampled, including 20 from extant taxa and 50 from extinct taxa. We obtained the blood flow rate (Q̇) based on foramina area and performed PGLS and phylogenetic ANCOVA in order to explore differences among mammalian groups. Our results show that, among mammals, taxa commonly associated with lower metabolism like living xenarthrans showed relatively smaller foramina, while the foramina of giant extinct xenarthrans like ground sloths and glyptodonts overlapped with non-xenarthran placentals. Consequently, Q̇ estimations indicated aerobic capacities comparable to other placental giant taxa like elephants or some ungulates. Furthermore, the estimation of the MMR for fossil giant taxa showed similar results, with almost all taxa showing high values except for those for which strong semi-arboreal or fossorial habits have been proposed. Moreover, the results are compatible with the diets predicted for extinct taxa, which indicate a strong consumption of grass similar to ungulates and in contrast to the folivorous or insectivorous diets of extant xenarthrans. The ancestral reconstruction of the MMR values indicated a lack of a common pattern for all xenarthrans, strongly supporting the occurrence of low metabolic rates in extant forms due to their particular dietary preferences and arboreal or fossorial habits. Our results highlight the importance of considering different evidence beyond the phylogenetic position of extinct taxa, especially when extinct forms are exceptionally different from their extant relatives. Future studies evaluating the energetic needs of giant extinct xenarthrans should not assume lower metabolic rates for these extinct animals based solely on their phylogenetic position and the observations on their extant relatives.

Genomic diversity and evolution of the Hawaiian Islands endemic Kokia (Malvaceae).

Island species are highly vulnerable due to habitat destruction and their often small population sizes with reduced genetic diversity. The Hawaiian Islands constitute the most isolated archipelago on the planet, harboring many endemic species. Kokia is an endangered flowering plant genus endemic to these islands, encompassing 3 extant and 1 extinct species. Recent studies provided evidence of unexpected genetic diversity within Kokia. Here, we provide high-quality genome assemblies for all 3 extant Kokia species, including an improved genome for Kokia drynarioides. All 3 Kokia genomes contain 12 chromosomes exhibiting high synteny within and between Kokia and the sister taxon Gossypioides kirkii. Gene content analysis revealed a net loss of genes in K. cookei compared to other species, whereas the gene complement in K. drynarioides remains stable and that of Kokia kauaiensis displays a net gain. A dated phylogeny estimates the divergence time from the last common ancestor for the 3 Kokia species at ∼1.2 million years ago (mya), with the sister taxa (K. cookei + K. drynarioides) diverging ∼0.8 mya. Kokia appears to have followed a stepping-stone pattern of colonization and diversification of the Hawaiian archipelago, likely starting on low or now submerged older islands. The genetic resources provided may benefit conservation efforts of this endangered endemic genus.