ABSTRACT
The mountain region of central Veracruz, Mexico hosts a large system of karst and volcanic caves that are unexplored. In particular, the vertebrates that inhabit these subterranean ecosystems are unknown. This study evaluated the diversity of mammals, birds, reptiles, amphibians, and fish in three environments (euphotic, disphotic, and aphotic) of 16 caves of different geological origin (12 karst caves and 4 volcanic caves) distributed along an altitudinal gradient (300-2400 m a.s.l.). We found a richness of 242 vertebrate species (184 birds, 30 mammals, 15 reptiles, 12 amphibians, and 1 fish) and an abundance of a total of 11,323 individuals (4,969 mammals, 6,483 birds, 36 reptiles, 27 amphibians, and 5 fish). The richness of all vertebrate classes was higher in karst than in volcanic caves. Vertebrate diversity was also higher at mid-altitudes between 600-899 m a.s.l. Diversity varied between environments, where bird and reptile richness was higher in the euphotic environment, while mammal and amphibian diversity was higher in the aphotic environment. The similarity in the composition of vertebrate species does not depend on the distance between karstic and volcanic caves. Volcanic and karst caves shared on average up to 70% and 55% of vertebrate species, which indicates that only 30% and 45% of species, respectively, is different in each cave type. Given the vulnerability and fragility of these subterranean ecosystems, as well as the important diversity that they contain, we recommend including the caves of the central region of Veracruz in the conservation agenda of local governments and communities. Community-based conservation can help ensure the presence of vertebrate species in the caves of this region.
Subject(s)
Biodiversity , Caves , Vertebrates , Animals , Mexico , Vertebrates/classification , Mammals , Reptiles/classification , Ecosystem , Amphibians , BirdsABSTRACT
The telencephalon of reptiles has been suggested to be the key to understanding the evolution of the forebrain. Nevertheless, a meaningful framework to organize the telencephalon in any reptile has, with rare exception, yet to be presented. To address this gap in knowledge, the telencephalon was investigated in two species of crocodiles. A variety of morphological stains were used to examine tissue in transverse, horizontal, and sagittal planes of sections. Besides providing a description of individual nuclei, brain parts were organized based on two features. One was related to two fixed, internal structures: the lateral ventricle and the dorsal medullary lamina. The other was the alignment of neurons into either layers, cortex, or not, nucleus. Viewed from this perspective, all structures, with limited exceptions, could be accurately placed within the telencephalon regardless of the plane of section. Furthermore, this framework can be applied to other reptiles. A further extension of this scheme suggests that all structures in the telencephalon could be grouped into one of two categories: pallial or basal.
Subject(s)
Alligators and Crocodiles , Telencephalon , Animals , Telencephalon/anatomy & histology , Alligators and Crocodiles/anatomy & histology , Neural Pathways/anatomy & histology , Reptiles/anatomy & histology , Neurons/cytologyABSTRACT
Sauroleishmania spp. comprises one of the four Leishmania subgenera, which has been historically considered a non-pathogenic protozoan of reptiles. However, some strains appear to be transiently infective to mammals, and recent findings have detected these parasites in dogs and humans in areas where leishmaniasis is endemic. Herein, the digestion pattern of PCR-RFLP of the 234 bp-hsp70 fragment was evaluated as a simpler and cheaper tool to distinguish the Sauroleishmania species from the other Leishmania subgenera. As a result, the digestion of the 234 bp-hsp70 fragments with HaeIII produced a banding pattern specific to the four Sauroleishmania strains assessed. This technique could contribute to the identification of Leishmania parasites isolated from sandflies, reptiles, or even mammals in fieldworks as an alternative to the use of laborious and expensive methodologies.
Subject(s)
HSP70 Heat-Shock Proteins , Leishmania , Polymerase Chain Reaction , Polymorphism, Restriction Fragment Length , Animals , HSP70 Heat-Shock Proteins/genetics , Polymerase Chain Reaction/methods , Leishmania/genetics , Leishmania/classification , Leishmania/isolation & purification , Dogs , Humans , DNA, Protozoan/genetics , Parasitology/methods , Leishmaniasis/parasitology , Leishmaniasis/veterinary , Reptiles/parasitologyABSTRACT
Recent studies suggest that both stem- and crown-group Archosauria encompassed high ecological diversity during their initial Triassic radiation. We describe a new pseudosuchian archosaur, Benggwigwishingasuchus eremicarminis gen. et sp. nov., from the Anisian (Middle Triassic) Fossil Hill Member of the Favret Formation (Nevada, USA), a pelagic setting in the eastern Panthalassan Ocean characterized by the presence of abundant ammonoids and large-bodied ichthyosaurs. Coupled with archosauriforms from the eastern and western Tethys Ocean, Benggwigwishingasuchus reveals that pseudosuchians were also components of Panthalassan ocean coastal settings, establishing that the group occupied these habitats globally during the Middle Triassic. However, Benggwigwishingasuchus, Qianosuchus, and Ticinosuchus (two other pseudosuchians known from marine sediments) are not recovered in a monophyletic group, demonstrating that a nearshore marine lifestyle occurred widely across Archosauriformes during this time. Benggwigwishingasuchus is recovered as part of an expanded Poposauroidea, including several taxa (e.g. Mandasuchus, Mambawakalae) from the Middle Triassic Manda Beds of Tanzania among its basally branching members. This implies a greater undiscovered diversity of poposauroids during the Early Triassic, and supports that the group, and pseudosuchians more broadly, diversified rapidly following the End-Permian mass extinction.
Subject(s)
Fossils , Animals , Fossils/anatomy & histology , Nevada , Phylogeny , Reptiles/anatomy & histology , Reptiles/classification , Biological Evolution , EcosystemABSTRACT
The ever-increasing and expanding globalisation of trade and transport underpins the escalating global problem of biological invasions. Developing biosecurity infrastructures is crucial to anticipate and prevent the transport and introduction of invasive alien species. Still, robust and defensible forecasts of potential invaders are rare, especially for species without known invasion history. Here, we aim to support decision-making by developing a quantitative invasion risk assessment tool based on invasion syndromes (i.e., generalising typical attributes of invasive alien species). We implemented a workflow based on 'Multiple Imputation with Chain Equation' to estimate invasion syndromes from imputed datasets of species' life-history and ecological traits and macroecological patterns. Importantly, our models disentangle the factors explaining (i) transport and introduction and (ii) establishment. We showcase our tool by modelling the invasion syndromes of 466 amphibians and reptile species with invasion history. Then, we project these models to amphibians and reptiles worldwide (16,236 species [c.76% global coverage]) to identify species with a risk of being unintentionally transported and introduced, and risk of establishing alien populations. Our invasion syndrome models showed high predictive accuracy with a good balance between specificity and generality. Unintentionally transported and introduced species tend to be common and thrive well in human-disturbed habitats. In contrast, those with established alien populations tend to be large-sized, are habitat generalists, thrive well in human-disturbed habitats, and have large native geographic ranges. We forecast that 160 amphibians and reptiles without known invasion history could be unintentionally transported and introduced in the future. Among them, 57 species have a high risk of establishing alien populations. Our reliable, reproducible, transferable, statistically robust and scientifically defensible quantitative invasion risk assessment tool is a significant new addition to the suite of decision-support tools needed for developing a future-proof preventative biosecurity globally.
Subject(s)
Amphibians , Forecasting , Introduced Species , Reptiles , Animals , Reptiles/physiology , Amphibians/physiology , Risk Assessment/methods , Models, Theoretical , Models, BiologicalABSTRACT
Most described species have not been explicitly included in phylogenetic trees-a problem named the Darwinian shortfall-owing to a lack of molecular and/or morphological data, thus hampering the explicit incorporation of evolution into large-scale biodiversity analyses. We investigate potential drivers of the Darwinian shortfall in tetrapods, a group in which at least one-third of described species still lack phylogenetic data, thus necessitating the imputation of their evolutionary relationships in fully sampled phylogenies. We show that the number of preserved specimens in scientific collections is the main driver of phylogenetic knowledge accumulation, highlighting the major role of biological collections in unveiling novel biodiversity data and the importance of continued sampling efforts to reduce knowledge gaps. Additionally, large-bodied and wide-ranged species, as well as terrestrial and aquatic amphibians and reptiles, are phylogenetically better known. Future efforts should prioritize phylogenetic research on organisms that are narrow-ranged, small-bodied and underrepresented in scientific collections, such as fossorial species. Addressing the Darwinian shortfall will be imperative for advancing our understanding of evolutionary drivers shaping biodiversity patterns and implementing comprehensive conservation strategies.
Subject(s)
Biodiversity , Biological Evolution , Phylogeny , Vertebrates , Animals , Vertebrates/genetics , Vertebrates/classification , Amphibians/genetics , Amphibians/classification , Reptiles/classification , Reptiles/geneticsABSTRACT
Transposable elements (TEs) are repetitive DNA sequences which create mutations and generate genetic diversity across the tree of life. In amniote vertebrates, TEs have been mainly studied in mammals and birds, whose genomes generally display low TE diversity. Squamates (Order Squamata; including â¼11,000 extant species of lizards and snakes) show as much variation in TE abundance and activity as they do in species and phenotypes. Despite this high TE activity, squamate genomes are remarkably uniform in size. We hypothesize that novel, lineage-specific genome dynamics have evolved over the course of squamate evolution. To understand the interplay between TEs and host genomes, we analyzed the evolutionary history of the chicken repeat 1 (CR1) retrotransposon, a TE family found in most tetrapod genomes which is the dominant TE in most reptiles. We compared 113 squamate genomes to the genomes of turtles, crocodilians, and birds and used ancestral state reconstruction to identify shifts in the rate of CR1 copy number evolution across reptiles. We analyzed the repeat landscapes of CR1 in squamate genomes and determined that shifts in the rate of CR1 copy number evolution are associated with lineage-specific variation in CR1 activity. We then used phylogenetic reconstruction of CR1 subfamilies across amniotes to reveal both recent and ancient CR1 subclades across the squamate tree of life. The patterns of CR1 evolution in squamates contrast other amniotes, suggesting key differences in how TEs interact with different host genomes and at different points across evolutionary history.
Subject(s)
Evolution, Molecular , Genome , Reptiles , Retroelements , Animals , Reptiles/genetics , Reptiles/classification , Phylogeny , Lizards/genetics , Chickens/geneticsABSTRACT
Harmful algal blooms (HABs) are a persistent and increasing problem globally, yet we still have limited knowledge about how they affect wildlife. Although semi-aquatic and aquatic amphibians and reptiles have experienced large declines and occupy environments where HABs are increasingly problematic, their vulnerability to HABs remains unclear. To inform monitoring, management, and future research, we conducted a literature review, synthesized the studies, and report on the mortality events describing effects of cyanotoxins from HABs on freshwater herpetofauna. Our review identified 37 unique studies and 71 endpoints (no-observed-effect and lowest-observed-effect concentrations) involving 11 amphibian and 3 reptile species worldwide. Responses varied widely among studies, species, and exposure concentrations used in experiments. Concentrations causing lethal and sublethal effects in laboratory experiments were generally 1 to 100 µg/L, which contains the mean value of reported HAB events but is 70 times less than the maximum cyanotoxin concentrations reported in the environment. However, one species of amphibian was tolerant to concentrations of 10,000 µg/L, demonstrating potentially immense differences in sensitivities. Most studies focused on microcystin-LR (MC-LR), which can increase systemic inflammation and harm the digestive system, reproductive organs, liver, kidneys, and development. The few studies on other cyanotoxins illustrated that effects resembled those of MC-LR at similar concentrations, but more research is needed to describe effects of other cyanotoxins and mixtures of cyanotoxins that commonly occur in the environment. All experimental studies were on larval and adult amphibians; there were no such studies on reptiles. Experimental work with reptiles and adult amphibians is needed to clarify thresholds of tolerance. Only nine mortality events were reported, mostly for reptiles. Given that amphibians likely decay faster than reptiles, which have tissues that resist decomposition, mass amphibian mortality events from HABs have likely been under-reported. We propose that future efforts should be focused on seven major areas, to enhance our understanding of effects and monitoring of HABs on herpetofauna that fill important roles in freshwater and terrestrial environments. Environ Toxicol Chem 2024;43:1936-1949. Published 2024. This article is a U.S. Government work and is in the public domain in the USA. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.
Subject(s)
Amphibians , Harmful Algal Bloom , Reptiles , Animals , Microcystins/toxicity , Environmental Monitoring , Water Pollutants, Chemical/toxicity , Marine Toxins/toxicityABSTRACT
Unravelling the functional steps that underlie major transitions in the fossil record is a significant challenge for biologists owing to the difficulties of interpreting functional capabilities of extinct organisms. New computational modelling approaches provide exciting avenues for testing function in the fossil record. Here, we conduct digital bending experiments to reconstruct vertebral function in non-mammalian synapsids, the extinct forerunners of mammals, to provide insights into the functional underpinnings of the synapsid-mammal transition. We estimate range of motion and stiffness of intervertebral joints in eight non-mammalian synapsid species alongside a comparative sample of extant tetrapods, including salamanders, reptiles and mammals. We show that several key aspects of mammalian vertebral function evolved outside crown Mammalia. Compared to early diverging non-mammalian synapsids, cynodonts stabilized the posterior trunk against lateroflexion, while evolving axial rotation in the anterior trunk. This was later accompanied by posterior sagittal bending in crown mammals, and perhaps even therians specifically. Our data also support the prior hypothesis that functional diversification of the mammalian trunk occurred via co-option of existing morphological regions in response to changing selective demands. Thus, multiple functional and evolutionary steps underlie the origin of remarkable complexity in the mammalian backbone.
Subject(s)
Biological Evolution , Fossils , Mammals , Spine , Animals , Mammals/physiology , Fossils/anatomy & histology , Spine/anatomy & histology , Spine/physiology , Biomechanical Phenomena , Range of Motion, Articular , Reptiles/physiology , Reptiles/anatomy & histologyABSTRACT
Tetrapods (amphibians, reptiles, birds, and mammals) are model systems for global biodiversity science, but continuing data gaps, limited data standardisation, and ongoing flux in taxonomic nomenclature constrain integrative research on this group and potentially cause biased inference. We combined and harmonised taxonomic, spatial, phylogenetic, and attribute data with phylogeny-based multiple imputation to provide a comprehensive data resource (TetrapodTraits 1.0.0) that includes values, predictions, and sources for body size, activity time, micro- and macrohabitat, ecosystem, threat status, biogeography, insularity, environmental preferences, and human influence, for all 33,281 tetrapod species covered in recent fully sampled phylogenies. We assess gaps and biases across taxa and space, finding that shared data missing in attribute values increased with taxon-level completeness and richness across clades. Prediction of missing attribute values using multiple imputation revealed substantial changes in estimated macroecological patterns. These results highlight biases incurred by nonrandom missingness and strategies to best address them. While there is an obvious need for further data collection and updates, our phylogeny-informed database of tetrapod traits can support a more comprehensive representation of tetrapod species and their attributes in ecology, evolution, and conservation research.
Subject(s)
Biodiversity , Birds , Mammals , Phylogeny , Reptiles , Animals , Reptiles/classification , Amphibians , Ecosystem , Bias , Humans , Body SizeABSTRACT
Micronucleus (MN) cell counting emerged in 1973-1975 as a valid alternative for characterizing chromosomal damage caused by different agents. It was first described in mammals, but its application was rapidly extended to other vertebrates, mainly fish. However, it was not until 28 years later that this test was implemented in studies on reptiles. Nowadays, reptiles are found to be excellent non-target species from environmental contamination exposure and MN test has become a fundamental tool for analyzing genotoxic effects induced by various xenobiotics. In this article we provide an updated review of the application of the MN test in reptile species, from an ecotoxicological perspective. Therefore, we present (I) a bibliometric analysis of the available research on genotoxic-induced MN formation in reptile species; (II) the use of reptiles as sentinel organisms in ecotoxicological studies; and (III) the strength and weakness of the application of the MN test in this group. With this review, we aim to provide a comprehensive view on the use of the MN test in ecotoxicology and to encourage further studies involving reptile species.
Subject(s)
Micronucleus Tests , Reptiles , Animals , Reptiles/genetics , Micronucleus Tests/methods , Mutagens/toxicity , Ecotoxicology/methods , DNA Damage/drug effects , Sentinel Species/geneticsABSTRACT
Sauropterygians were the stratigraphically longest-ranging clade of Mesozoic marine reptiles with a global fossil record spanning â¼180 million years1. However, their early evolution has only been known from what is now the Northern Hemisphere, extending across the northern and trans-equatorial western margins of the Tethys paleo-ocean1 after the late-Early Triassic (late Olenekian, â¼248.8 million years [Ma] ago2), and via possible trans-Arctic migration1 to the Eastern Panthalassa super-ocean prior to the earliest Middle Triassic (Olenekian-earliest Anisian3,4, â¼247 Ma). Here, we describe the geologically oldest sea-going reptile from the Southern Hemisphere - a nothosaur (basal sauropterygian5) from the Middle Triassic (Anisian, after â¼246 Ma6) of New Zealand. Time-scaled ancestral range estimations thus reveal an unexpected circum-Gondwanan high-paleolatitude (>60° S7) dispersal from a northern Tethyan origination center. This coincides with the adaptive diversification of sauropterygians after the end-Permian mass extinction8 and suggests that rapid globalization accompanied their initial radiation in the earliest Mesozoic.
Subject(s)
Biological Evolution , Fossils , Reptiles , Animals , Fossils/anatomy & histology , Reptiles/anatomy & histology , Reptiles/classification , Reptiles/physiology , New Zealand , Animal Distribution , Aquatic Organisms , Internationality , PhylogenyABSTRACT
Blastocystis inhabits the digestive tracts of a diverse range of hosts. Transmission patterns, including host specificity, and the clinical and public health significance of Blastocystis in humans remain poorly understood. This study aimed to investigate the distribution and genetic diversity of Blastocystis in herbivorous and carnivorous reptiles in Eastern Thailand. A total of 501 faecal samples were collected from 363 iguanas, 79 bearded dragons, 50 tortoises, and nine snakes in an animal breeding farm in Chonburi Province, Eastern Thailand. Detection and differentiation of Blastocystis was based on amplification, sequencing, and phylogenetic analysis of specific small subunit (SSU) ribosomal RNA genes from faecal DNA extracted from the samples. Altogether 101/501 samples (20â¯%) were polymerase chain reaction (PCR) and sequencing-positive for Blastocystis, 90 (89â¯%) of which were from iguanas; the remaining positive samples were from African spurred tortoise (n=6), Bearded dragon (n=3), Leopard tortoise (n=1), and Red-footed tortoise (n=1). Phylogenetic analysis revealed that most of the Blastocystis sequences from iguanas were largely similar, and they were distinct from those of the tortoises. Subtype 17 was found in the three bearded dragons and likely reflected Blastocystis from prey animals. This is the largest survey of Blastocystis in reptiles to date. Remarkable differences in Blastocystis colonization rates and genetic diversity were observed between iguanas and other reptile orders, and what was considered Blastocystis colonization was only observed in herbivorous reptiles.
Subject(s)
Blastocystis Infections , Blastocystis , Feces , Genetic Variation , Host Specificity , Phylogeny , Animals , Blastocystis/genetics , Blastocystis/classification , Thailand/epidemiology , Blastocystis Infections/veterinary , Blastocystis Infections/parasitology , Blastocystis Infections/epidemiology , Blastocystis Infections/transmission , Feces/parasitology , Reptiles/parasitology , Turtles/parasitology , Lizards/parasitology , Snakes/parasitologyABSTRACT
An often-overlooked question of the biodiversity crisis is how natural hazards contribute to species extinction risk. To address this issue, we explored how four natural hazards, earthquakes, hurricanes, tsunamis, and volcanoes, overlapped with the distribution ranges of amphibians, birds, mammals, and reptiles that have either narrow distributions or populations with few mature individuals. To assess which species are at risk from these natural hazards, we combined the frequency and magnitude of each natural hazard to estimate their impact. We considered species at risk if they overlapped with regions where any of the four natural hazards historically occurred (n = 3,722). Those species with at least a quarter of their range subjected to a high relative impact were considered at high risk (n = 2,001) of extinction due to natural hazards. In total, 834 reptiles, 617 amphibians, 302 birds, and 248 mammals were at high risk and they were mainly distributed on islands and in the tropics. Hurricanes (n = 983) and earthquakes (n = 868) affected most species, while tsunamis (n = 272), and volcanoes (n = 171) affected considerably fewer. The region with the highest number of species at high risk was the Pacific Ring of Fire, especially due to volcanoes, earthquakes, and tsunamis, while hurricane-related high-risk species were concentrated in the Caribbean Sea, Gulf of Mexico, and northwestern Pacific Ocean. Our study provides important information regarding the species at risk due to natural hazards and can help guide conservation attention and efforts to safeguard their survival.
Subject(s)
Biodiversity , Extinction, Biological , Animals , Birds , Mammals , Reptiles , Earthquakes , Cyclonic Storms , Tsunamis , Amphibians , Volcanic Eruptions , Natural DisastersABSTRACT
Long-term ecological monitoring is crucial to understanding the complex dynamics of ecosystems, communities, and populations. Despite this, monitoring data are lacking or rare for the vast majority of biodiversity. Here we report the results of 19 years (2003-2022) of continuous annual monitoring of reptile species at Booderee National Park (BNP) on the east coast of south-eastern Australia. We tested the effects of time, habitat type, fire, and climate on detections of five reptile species. Our study revealed declines in detections of two skink species over time (Lampropholis delicata and Ctenotus taeniolatus), which we suspect was partly driven by weather conditions influencing activity of these species. We also identified broad vegetation type associations for two congeneric species with L. delicata being associated with forested sites, and Lampropholis guichenoti associated with more shrubby sites. Our results also demonstrated a clear association between Cryptophis nigrescens and L. delicata and fire, with the probabilities of detection of both species decreasing with time since fire in the short term. At about the midway point of our study (in 2011), we were forced to make a change in the way our data were collected. The change heavily influenced our findings, and so breached the integrity of the time series in our dataset. We acknowledge that a simple but crucial step to mitigate this breach would have been to conduct calibration that allowed subsequent analysis to control for a change in field survey methodology. Whilst improvements in the effectiveness of field survey methods might be possible through new technologies, it is crucial to maintain the integrity of long-term datasets as data collection continues.
Subject(s)
Ecosystem , Reptiles , Animals , Reptiles/physiology , Biodiversity , Australia , FiresABSTRACT
Solute carrier family 26 (Slc26) is a family of anion exchangers with 11 members in mammals (named Slc26a1-a11). Here, we identified a novel member of the slc26 family, slc26a12, located in tandem with slc26a2 in the genomes of several vertebrate lineages. BLAST and synteny analyses of various jawed vertebrate genome databases revealed that slc26a12 is present in coelacanths, amphibians, reptiles, and birds but not in cartilaginous fishes, lungfish, mammals, or ray-finned fishes. In some avian and reptilian lineages such as owls, penguins, egrets, and ducks, and most turtles examined, slc26a12 was lost or pseudogenized. Phylogenetic analysis showed that Slc26a12 formed an independent branch with the other Slc26 members and Slc26a12, Slc26a1 and Slc26a2 formed a single branch, suggesting that these three members formed a subfamily in Slc26. In jawless fish, hagfish have two genes homologous to slc26a2 and slc26a12, whereas lamprey has a single gene homologous to slc26a2. African clawed frogs express slc26a12 in larval gills, skin, and fins. These results show that slc26a12 was present at least before the separation of lobe-finned fish and tetrapods; the name slc26a12 is appropriate because the gene duplication occurred in the distant past.
Subject(s)
Evolution, Molecular , Phylogeny , Sulfate Transporters , Animals , Amphibians/genetics , Amphibians/metabolism , Birds/genetics , Reptiles/genetics , Sulfate Transporters/genetics , Sulfate Transporters/metabolismABSTRACT
Before the rise of dinosaurs and pterosaurs, pseudosuchians-reptiles from the crocodilian lineage-dominated the Triassic land ecosystems. This lineage diversified into several less inclusive clades, resulting in a wide ecomorphological diversity during the Middle and Late Triassic. Some giant pseudosuchians occupied the top of the trophic webs, while others developed extensive bony armor as a defense mechanism, which later evolved as a convergence in the avemetatarsalian lineage. On the other hand, there were groups like the Gracilisuchidae, which was composed of carnivorous forms with lightweight build and less than 1 m in length. The fossil record of gracilisuchids is geographically restricted to China and Argentina, with one ambiguous record from Brazil. In the present study, the first unambiguous gracilisuchid from Brazil is described. Parvosuchus aurelioi gen. et sp. nov. comes from the Dinodontosaurus Assemblage Zone of the Santa Maria Formation, which is associated with the Ladinian-Carnian boundary. Composed of a complete cranium, vertebrae, pelvic girdle and hindlimbs, the new species nests with Gracilisuchus stipanicicorum and Maehary bonapartei in a phylogenetic analysis. Its discovery fills a taxonomic gap in Brazilian pseudosuchian fauna and reveals the smallest known member of this clade from the Dinodontosaurus Assemblage Zone, highlighting the diversity of pseudosuchians during the moment that preceded the dawn of dinosaurs.
Subject(s)
Dinosaurs , Fossils , Phylogeny , Animals , Fossils/anatomy & histology , Brazil , Dinosaurs/anatomy & histology , Dinosaurs/classification , Biological Evolution , Reptiles/anatomy & histology , Reptiles/classification , Predatory Behavior , Skull/anatomy & histologyABSTRACT
Biological invasions are among the threats to global biodiversity and social sustainability, especially on islands. Identifying the threshold of area at which non-native species begin to increase abruptly is crucial for early prevention strategies. The small-island effect (SIE) was proposed to quantify the nonlinear relationship between native species richness and area but has not yet been applied to non-native species and thus to predict the key breakpoints at which established non-native species start to increase rapidly. Based on an extensive global dataset, including 769 species of non-native birds, mammals, amphibians and reptiles established on 4277 islands across 54 archipelagos, we detected a high prevalence of SIEs across 66.7% of archipelagos. Approximately 50% of islands have reached the threshold area and thus may be undergoing a rapid increase in biological invasions. SIEs were more likely to occur in those archipelagos with more non-native species introduction events, more established historical non-native species, lower habitat diversity and larger archipelago area range. Our findings may have important implications not only for targeted surveillance of biological invasions on global islands but also for predicting the responses of both non-native and native species to ongoing habitat fragmentation under sustained land-use modification and climate change.
Subject(s)
Biodiversity , Introduced Species , Islands , Animals , Conservation of Natural Resources , Ecosystem , Birds/physiology , Amphibians/physiology , Mammals/physiology , Reptiles/physiologyABSTRACT
In ectothermic vertebrates, behavioral fever, where an individual actively seeks warmer areas, seems to be a primary response to pathogens. This is considered a broad and evolutionarily conserved response among vertebrates. Recent population declines in amphibians are associated with an increase of infectious disease driven largely by climate change, habitat degradation, and pollution. Immediate action through research is required to better understand and inform conservation efforts. The literature available, does not provide unifying concepts that can guide adequate experimental protocols and interpretation of data, especially when studying animals in the field. The aim of this review is to promote common understanding of terminology and facilitating improved comprehension and application of key concepts about the occurrence of both sickness behavior or behavioral fever in ectothermic vertebrates. We start with a conceptual synthesis of sickness behavior and behavioral fever, with examples in different taxa. Through this discussion we present possible paths to standardize terminology, starting from original use in endothermic tetrapods which was expanded to ectothermic vertebrates, particularly amphibians and reptiles. This conceptual expansion from humans (endothermic vertebrates) and then to ectothermic counterparts, gravitates around the concept of 'normality'. Thus, following this discussion, we highlight caveats with experimental protocols and state the need of a reference value considered normal (RVCN), which is different from experimental control and make recommendations regarding experimental procedures and stress the value of detailed documentation of behavioral responses. We also propose some future directions that could enhance interaction among disciplines, emphasizing relationships at different levels of biological organization. This is crucial given the increasing convergence of fields such as thermal physiology, immunology, and animal behavior due to emerging diseases and other global crises impacting biodiversity.