Search

Climate change particularly affects ectothermic reptiles that cannot regulate their internal temperature metabolically. But it is difficult to anticipate how the unprecedented pace of current climate change will affect these animals based only on recent data. We need a larger temporal context based on historical data spanning deeper time scales and past episodes of rapid climate change. Body size is a suitable response variable to test in such investigations because data from extant taxa can predict body size for fossil specimens from the same lineages. We can also reconstruct past climate parameters from terrestrial and marine proxies. Metabolic theory for ectothermic vertebrates predicts that maximum body size should correlate with environmental temperature over ecological time scales. Here, I test this theory on an evolutionary time scale, using both paleotemperature and paleoprecipitation, for two different higher order reptile groups occupying different habitats. I hypothesize that maximum snout-vent length (SVL) in terrestrial lizards and semiaquatic crocodyliforms tracks temperature and precipitation over geologic time intervals, and that these patterns emerge across both regional and local geographic scales. I measured 283 lizard and 280 crocodyliform fossil specimens from intermontane basins across the Western Interior of North America through the Paleogene (66-23 million years ago), which spans several warming and cooling events. Most of the fossil record of these animals consists of individual cranial or limb bones. I therefore collected an additional extensive dataset of measurements from extant specimens to develop regression equations for estimating SVL from isolated anatomical elements. I applied these methods to reconstruct lizard body sizes through the Paleogene using the available fossil record (Chapter 1). I then used similar methods to investigate whether deep time body size evolution patterns in terrestrial lizards compared to those of contemporaneous amphibious crocodyliforms, and to see how those patterns compared at regional vs. local geographic scales (Chapter 2). Finally, I collected over 100 estimates each for mean annual paleotemperature (MAPT) and paleoprecipitation (MAPP) and tested for correlation between these variables and maximum body size in lizards or crocodyliforms (Chapter 3).My results indicated that during the warmest interval in the early Eocene, maximum lizard body size increased to almost one meter, even rivaling some co-occurring crocodyliforms in body size. Maximum lizard SVL demonstrated a positive linear relationship with local terrestrial temperature within basin assemblages over geologic time scales but did not correlate as strongly with temperatures averaged across the Western Interior. In contrast to the lizards, maximum crocodyliform SVL (about 2 meters) was consistently high across the intermontane basins through the Paleogene and indicated a strong relationship to paleoprecipitation rather than paleotemperature. Large-bodied crocodyliforms were most abundant in localities that hosted large bodies of water at the time of deposition. Maximum body size and diversity decreased for both lizards and crocodyliforms in the early Oligocene, when the Western Interior experienced cooling and aridification. Neontological studies of lizard and crocodylian ecology and physiology corroborate these paleontological observations. These results offer new evidence that climate variables affect body size in ectothermic reptiles on evolutionary time scales, which deepens our understanding of these dynamics on ecological time scales. Studies that integrate data across time scales and biological hierarchies and can inform conservation efforts under current rapid climate change.

The DAN gene family (DAN, Differential screening-selected gene Aberrant in Neuroblastoma) is a group of genes that is expressed during development and plays fundamental roles in limb bud formation and digitation, kidney formation and morphogenesis and left-right axis specification. During adulthood the expression of these genes are associated with diseases, including cancer. Although most of the attention to this group of genes has been dedicated to understanding its role in physiology and development, its evolutionary history remains poorly understood. Thus, the goal of this study is to investigate the evolutionary history of the DAN gene family in vertebrates, with the objective of complementing the already abundant physiological information with an evolutionary context. Our results recovered the monophyly of all DAN gene family members and divide them into five main groups. In addition to the well-known DAN genes, our phylogenetic results revealed the presence of two new DAN gene lineages; one is only retained in cephalochordates, whereas the other one (GREM3) was only identified in cartilaginous fish, holostean fish, and coelacanth. According to the phyletic distribution of the genes, the ancestor of gnathostomes possessed a repertoire of eight DAN genes, and during the radiation of the group GREM1, GREM2, SOST, SOSTDC1, and NBL1 were retained in all major groups, whereas, GREM3, CER1, and DAND5 were differentially lost.

Coxiella burnetii, the causative bacterium of the zoonotic disease Q fever, has been documented in many different species. We describe documented turtles that were PCR positive for C. burnetii from multiple locations in Illinois and Wisconsin, USA. Assessing the conservation implications, reservoir potential, and zoonotic risk requires further research.

A total of 79 species of local vertebrates (birds, mammals, and reptiles) are found to be in illegal trade in the West Bank, Palestine, during 2013–2020. Data were collected from visits to the animal markets in the main cities of the West Bank (Bethlehem, Hebron, Jenin, Jericho, Nablus, Ramallah, and Salfit) and from advertisements in social media. Birds were the most traded animals represented in 59 species (74.7%), followed by 12 species of reptiles (15.2%) and eight species of mammals (10.1%). Nineteen species are listed under CITES appendices (17 birds and 2 mammals under appendixes II and III, respectively). As for the conservation status according to the IUCN Red List, two bird species (Streptopelia turtur and Serinus syriacus) and one reptile (Testudo graeca) are listed as VU, while two mammals (Hyaena hyaena and Gazella gazella) are listed as NT and EN, respectively. Based on the local status, three species of bird are considered critically endangered (Coturnix coturnix, Asio flammeus, and Aquila chrysaetos), one bird is endangered (Falco subbuteo), and two mammals (Hyaena hyaena and Gazella gazella) are considered endangered and vulnerable respectively. This study reveals the urgent need to control animal trade in the Palestinian Territories.

The remarkably thin rostrum in the Indian gharial (Gavialis gangeticus) imparts challenges to nasal physiology. Competition for space in the slim jaws necessitates a thin nasal septum, leaving this taxon susceptible to nasal passage abnormalities such as septal deviation. Here we describe the nasal anatomy of gharials based on multiple individuals including one that showcases an extreme instance of nasal septum deviation. We found that gharials have both confluent nostrils and choanae, which may be important for their unique nasal acoustics. The deviated nasal septum in the female showed distinct waviness that affected the nasal passages by alternately compressing them. We performed a computational fluid dynamic analysis on the nasal passages to visualize the effects of septal deviation on airflow. Our analysis found the deviated septum increased nasal resistance and wall shear stress during respiration, resulting in unequal distribution of the air field between both sides of the nasal passage. Our findings indicate that gharials-and potentially other longirostrine crocodylians-may be particularly susceptible to septal deviations. Lastly, we observed pterygoid bullae to be present in both sexes, though their morphology differed. Airflow in the male pterygoid bullae produced a Bernoulli effect which may be responsible for the unique "pop" sounds recorded in this species.

The author previously worked extensively on the broad problem of the evolution of the vertebrate pallium. He proposed various Bauplan models covering at least gnathostomes, based in the definition of a set of pallial sectors with topologically invariant positional relationships and distinct molecular profiles. Out of one of these models, presented as the “updated tetrapartite pallium model,” a modified definition of the earlier lateral pallium sector (LPall) concept emerged, characterizing it in mammals as an unitary claustro-insular transitional (mesocortical) complex intercalated between the neocortex or dorsal pallium (DPall) above and olfactory cortex or ventral pallium (VPall) underneath. A distinctive molecular marker of the early-born deep claustral component of the LPall was found to be the transcription factor Nr4a2, which is not expressed significantly in the overlying insular cortex or in adjoining cortical territories. Given that earlier comparative studies had identified molecularly and topologically comparable VPall, LPall, and DPall sectors in the avian pallium, an avian Nr4a2 probe was applied, aiming to identify the reportedly absent avian claustro-insular complex. An early-born superficial subpopulation of the avian LPall that expresses this marker selectively through development was indeed found. This was proposed to be a claustrum homolog, whereas the remaining Nr4a2-negative avian LPall cells were assumed to represent a possible insular homolog. This last notion was subsequently supported by comparable selective expression of the mouse insular marker Cyp26b, also found restricted to the avian LPall. Some published data suggested that similar molecular properties and structure apply at the reptilian LPall. This analysis was reviewed in Puelles et al. [The pallium in reptiles and birds in the light of the updated tetrapartite pallium model. 2017]. Four years on, the present commentary discusses some international publications accrued in the interval that touch on the claustro-insular homology hypothesis. Some of them are opposed to the hypothesis whereas others corroborate or support it. This raises a number of secondary issues of general interest.

Hepatozoon and Hemolivia are members of the haemogregarines and are reported in reptiles and reptile-associated ticks. However, no studies have reported on Hepatozoon and Hemolivia in Japanese reptile-associated ticks. This study aimed to molecularly identify and to characterize Hepatozoon and Hemolivia in Japanese reptile-associated ticks, Amblyomma geoemydae (Cantor, 1847) and Amblyomma nitidum (Hirst & Hirst, 1910). A total of 41 and 75 DNA samples from A. geoemydae and A. nitidum ticks, respectively, were used for screening of Hepatozoon and Hemolivia with polymerase chain reaction targeting 18S rDNA. As a result, Hemolivia and Hepatozoon were detected in two A. geoemydae and one A. nitidum, respectively. The sequences of Hemolivia spp. showed a 99.5% (1,050/1,055 bp) identity with Hemolivia parvula (KR069083), and the Hemolivia spp. were located in the same clade as H. parvula in the phylogenetic tree. The sequences of Hepatozoon sp. showed a 98.4% (1,521/1,545 bp) identity with Hepatozoon colubri (MN723844), and the Hepatozoon sp. was distinct from validated Hepatozoon species in the tree. Our findings highlight the first molecular record of Hemolivia in Japan and present the first detection of Hepatozoon in A. nitidum. Further investigations on these tick-borne protozoa are required to understand their life cycle and pathogenicity.

Commonly used 16S rRNA gene primers do not detect the full range of archaeal diversity present in the vertebrate gut. As a result, several questions regarding the archaeal component of the gut microbiota remain, including which Archaea are host-associated, the specificities of such associations and the major factors influencing archaeal diversity. Using 16S rRNA gene amplicon sequencing with primers that specifically target Archaea, we obtained sufficient sequence data from 185 gastrointestinal samples collected from 110 vertebrate species that span five taxonomic classes (Mammalia, Aves, Reptilia, Amphibia and Actinopterygii), of which the majority were wild. We provide evidence for previously undescribed Archaea–host associations, including Bathyarchaeia and Methanothermobacter, the latter of which was prevalent among Aves and relatively abundant in species with higher body temperatures, although this association could not be decoupled from host phylogeny. Host phylogeny explained archaeal diversity more strongly than diet, while specific taxa were associated with both factors, and cophylogeny was significant and strongest for mammalian herbivores. Methanobacteria was the only class predicted to be present in the last common ancestors of mammals and all host species. Further analysis indicated that Archaea–Bacteria interactions have a limited effect on archaeal diversity. These findings expand our current understanding of Archaea–vertebrate associations., Analysis of the archaeal gut microbiota of 110 vertebrate species spanning five taxonomic classes revealed that host phylogeny could explain archaeal diversity.

There is a high rate of recent species discovery in remote regions of northern Australia, especially for amphibians and reptiles. The Wessel Islands, located in the northeastern corner of the Northern Territory, has recently been identified as a region of high species and phylogenetic endemism based on samples collected during the sole reptile and amphibian survey there in 1993. Using a phylogenetic approach, we describe a new, evolutionarily distinct species of Uperoleia endemic to the Wessel Islands. This description is based on three specimens, one female and two juveniles, which represent the only confirmed vouchers of the species. Due to the low number of specimens, this new species cannot be diagnosed morphologically from other closely related Uperoleia, and nothing is currently known about the mating call or basic biology. The discovery of this species provides further evidence for the islands’ importance as an area of endemism and identifies an urgent need for further surveys to document the unique biological diversity of the Wessel Islands.

Increases in phenotypic variation under extreme (e.g. novel or stressful) environmental conditions are emerging as a crucial process through which evolutionary adaptation can occur. Lack of prior stabilizing selection, as well as potential instability of developmental processes in these environments, may lead to a release of phenotypic variation that can have important evolutionary consequences. Although such patterns have been shown in model study organisms, we know little about the generality of trait variance across environments for non-model organisms. Here, we test whether extreme developmental temperatures increase the phenotypic variation across diverse reptile taxa. We find that the among-individual variation in a key life-history trait (post-hatching growth) increases at extreme cold and hot temperatures. However, variations in two measures of hatchling morphology and in hatchling performance were not related to developmental temperature. Although extreme developmental temperatures may increase the variation in growth, our results suggest that plastic responses to stressful incubation conditions do not generally make more extreme phenotypes available to selection. We discuss the reasons for the general lack of increased variability at extreme incubation temperatures and the implications this has for local adaptation in hatchling morphology and physiology.

Global warming could threaten over 400 species with temperature‐dependent sex determination (TSD) worldwide, including all species of sea turtle. During embryonic development, rising temperatures might lead to the overproduction of one sex and, in turn, could bias populations’ sex ratios to an extent that threatens their persistence. If climate change predictions are correct, and biased sex ratios reduce population viability, species with TSD may go rapidly extinct unless adaptive mechanisms, whether behavioural, physiological or molecular, exist to buffer these temperature‐driven effects. Here, we summarize the discovery of the TSD phenomenon and its still elusive evolutionary significance. We then review the molecular pathways underpinning TSD in model species, along with the hormonal mechanisms that interact with temperatures to determine an individual's sex. To illustrate evolutionary mechanisms that can affect sex determination, we focus on sea turtle biology, discussing both the adaptive potential of this threatened TSD taxon, and the risks associated with conservation mismanagement.

The Tree of Life will be irrevocably reshaped as anthropogenic extinctions continue to unfold. Theory suggests that lineage evolutionary dynamics, such as age since origination, historical extinction filters and speciation rates, have influenced ancient extinction patterns – but whether these factors also contribute to modern extinction risk is largely unknown. We examine evolutionary legacies in contemporary extinction risk for over 4000 genera, representing ~30,000 species, from the major tetrapod groups: amphibians, birds, turtles and crocodiles, squamate reptiles and mammals. We find consistent support for the hypothesis that extinction risk is elevated in lineages with higher recent speciation rates. We subsequently test, and find modest support for, a primary mechanism driving this pattern: that rapidly diversifying clades predominantly comprise range-restricted, and extinction-prone, species. These evolutionary patterns in current imperilment may have important consequences for how we manage the erosion of biological diversity across the Tree of Life.

Background Environmental fluctuation during embryonic and fetal development can permanently alter an organism’s morphology, physiology, and behaviour. This phenomenon, known as developmental plasticity, is particularly relevant to reptiles that develop in subterranean nests with variable oxygen tensions. Previous work has shown hypoxia permanently alters the cardiovascular system of snapping turtles and may improve cardiac anoxia tolerance later in life. The mechanisms driving this process are unknown but may involve epigenetic regulation of gene expression via DNA methylation. To test this hypothesis, we assessed in situ cardiac performance during 2 h of acute anoxia in juvenile turtles previously exposed to normoxia (21% oxygen) or hypoxia (10% oxygen) during embryogenesis. Next, we analysed DNA methylation and gene expression patterns in turtles from the same cohorts using whole genome bisulfite sequencing, which represents the first high-resolution investigation of DNA methylation patterns in any reptilian species. Results Genome-wide correlations between CpG and CpG island methylation and gene expression patterns in the snapping turtle were consistent with patterns observed in mammals. As hypothesized, developmental hypoxia increased juvenile turtle cardiac anoxia tolerance and programmed DNA methylation and gene expression patterns. Programmed differences in expression of genes such as SCN5A may account for differences in heart rate, while genes such as TNNT2 and TPM3 may underlie differences in calcium sensitivity and contractility of cardiomyocytes and cardiac inotropy. Finally, we identified putative transcription factor-binding sites in promoters and in differentially methylated CpG islands that suggest a model linking programming of DNA methylation during embryogenesis to differential gene expression and cardiovascular physiology later in life. Binding sites for hypoxia inducible factors (HIF1A, ARNT, and EPAS1) and key transcription factors activated by MAPK and BMP signaling (RREB1 and SMAD4) are implicated. Conclusions Our data strongly suggests that DNA methylation plays a conserved role in the regulation of gene expression in reptiles. We also show that embryonic hypoxia programs DNA methylation and gene expression patterns and that these changes are associated with enhanced cardiac anoxia tolerance later in life. Programming of cardiac anoxia tolerance has major ecological implications for snapping turtles, because these animals regularly exploit anoxic environments throughout their lifespan.

Wolbachia, a maternally transmitted Gram-negative endosymbiont of onchocercid nematodes and arthropods, has a role in the biology of their host; thus it has been exploited for the filariasis treatment in humans. To assess the presence and prevalence of this endosymbiont in reptiles and their ectoparasites, blood and tail tissue as well as ticks and mites collected from them were molecularly screened for Wolbachia DNA using two sets of primers targeting partial 16S rRNA and Wolbachia surface protein (wsp) genes. Positive samples were screened for the partial 12S rRNA and cytochrome c oxidase subunit 1 (cox1) genes for filarioids. Of the different species of lizards (Podarcis siculus, Podarcis muralis and Lacerta bilineata) and snakes (Elaphe quatuorlineata and Boa constrictor constrictor) screened from three collection sites, only P. siculus scored positive for Wolbachia 16S rRNA. Among ectoparasites collected from reptiles (Ixodes ricinus ticks and Neotrombicula autumnalis, Ophionyssus sauracum and Ophionyssus natricis mites), I. ricinus (n = 4; 2.8%; 95% CI, 0.9–7) from P. siculus, N. autumnalis (n = 2 each; 2.8%; 95% CI, 0.9–6.5) from P. siculus and P. muralis and O. natricis (n = 1; 14.3%; 95% CI, 0.7–55.4) from Boa constrictor constrictor scored positive for Wolbachia DNA. None of the positive Wolbachia samples scored positive for filarioids. This represents the first report of Wolbachia in reptilian hosts and their ectoparasites, which follows a single identification in the intestinal cells of a filarioid associated with a gecko. This data could contribute to better understand the reptile filarioid-Wolbachia association and to unveil the evolutionary pattern of Wolbachia in its filarial host.

Understanding the factors that cause heterogeneity among gene trees can increase the accuracy of species trees. Discordant signals across the genome are commonly produced by incomplete lineage sorting (ILS) and introgression, which in turn can result in reticulate evolution. Species tree inference using the multispecies coalescent is designed to deal with ILS and is robust to low levels of introgression, but extensive introgression violates the fundamental assumption that relationships are strictly bifurcating. In this study, we explore the phylogenomics of the iconic Liolaemus subgenus of South American lizards, a group of over 100 species mostly distributed in and around the Andes mountains. Using mitochondrial DNA (mtDNA) and genome-wide restriction site-associated DNA sequencing (RADseq; nDNA hereafter), we inferred a time-calibrated mtDNA gene tree, nDNA species trees, and phylogenetic networks. We found high levels of discordance between mtDNA and nDNA, which we attribute in part to extensive ILS resulting from rapid diversification. These data also reveal extensive and deep introgression, which combined with rapid diversification, explain the high level of phylogenetic discordance. We discuss these findings in the context of Andean orogeny and glacial cycles that fragmented, expanded, and contracted species distributions. Finally, we use the new phylogeny to resolve long-standing taxonomic issues in one of the most studied lizard groups in the New World.

Research focused on understanding the evolutionary factors that shape parity mode evolution among vertebrates have long focused on squamate reptiles (snakes and lizards), which contain all but one of the evolutionary transitions from oviparity to viviparity among extant amniotes. While most hypotheses have focused on the role of cool temperatures in favoring viviparity in thermoregulating snakes and lizards, there is a growing appreciation in the biogeographic literature for the importance of lower oxygen concentrations at high elevations for the evolution of parity mode. However, the physiological mechanisms underlying how hypoxia might reduce fitness, and how viviparity can alleviate this fitness decrement, has not been systematically evaluated. We qualitatively evaluated previous research on reproductive and developmental physiology, and found that (1) hypoxia can negatively affect fitness of squamate embryos, (2) oxygen availability in the circulatory system of adult lizards can be similar or greater than an egg, and (3) gravid females can possess adaptive phenotypic plasticity in response to hypoxia. These findings suggest that the impact of hypoxia on the development and physiology of oviparous and viviparous squamates would be a fruitful area of research for understanding the evolution of viviparity. To that end, we propose an integrative research program for studying hypoxia and the evolution of viviparity in squamates.

Aim To investigate whether the frequently advocated climate‐matching species distribution modeling approach could predict the well‐characterized colonization of Florida by the Madagascar giant day gecko Phelsuma grandis. Location Madagascar and Florida, USA. Methods To determine the climatic conditions associated with the native range of P. grandis, we used native‐range presence‐only records and Bioclim climatic data to build a Maxent species distribution model and projected the climatic thresholds of the native range onto Florida. We then built an analogous model using Florida presence‐only data and projected it onto Madagascar. We constructed a third model using native‐range presences for both P. grandis and the closely related parapatric species P. kochi. Results Despite performing well within the native range, our Madagascar Bioclim model failed to identify suitable climatic habitat currently occupied by P. grandis in Florida. The model constructed using Florida presences also failed to reflect the distribution in Madagascar by overpredicting distribution, especially in western areas occupied by P. kochi. The model built using the combined P. kochi/P. grandis dataset modestly improved the prediction of the range of P. grandis in Florida, thereby implying competitive exclusion of P. grandis by P. kochi from habitat within the former's fundamental niche. These findings thus suggest ecological release of P. grandis in Florida. However, because ecological release cannot fully explain the divergent occupied niches of P. grandis in Madagascar versus Florida, our findings also demonstrate some degree of in situ adaptation in Florida. Main conclusions Our models suggest that the discrepancy between the predicted and observed range of P. grandis in Florida is attributable to either in situ adaptation by P. grandis within Florida, or a combination of such in situ adaptation and competition with P. kochi in Madagascar. Our study demonstrates that climate‐matching species distribution models can severely underpredict the establishment risk posed by non‐native herpetofauna., Climate‐matching species distribution models (SDMs) are frequently used to predict biotic invasions. Our manuscript details how both release from native‐range competitors and in situ adaptation within the non‐native range have enabled the day gecko Phelsuma grandis to flourish in Florida under bioclimatic conditions classified as highly unsuitable by an otherwise‐well‐performing climate‐matching SDM. By identifying the large discrepancy between the predicted and observed range of P. grandis in Florida, our study highlights the shortcomings of climate‐matching SDMs as conservation management tools, while also providing valuable empirical evidence of the ecological and evolutionary processes underpinning this discrepancy.

The release of contaminants as herbicides, fungicides and insecticides into the environment has been listed as one of the six major contributors to the global decline of reptiles. Although reptiles may face severe risk from contaminants due to their ecology and physiology, they are currently less studied than other vertebrate groups. In the present work, we investigated if and how different types of field treatment (conventional and organic) affected the health status of Italian wall lizard (Podarcis siculus) individuals in central Italy. We chose a multi-biomarker approach that evaluated the biological responses of lizards to the treatment by means of AChE activity in the nervous system, biotransformation enzymes activities and oxidative stress in the liver, micronuclei frequency measured in the erythrocytes, and rate of intestinal parasitic infection. Our findings showed evidence of effects of treatment in conventional areas and between sexes with significant oxidative stress due to hydroxyl radicals, that caused DNA damage. No difference of intestinal parasite infections was found among treatments. Podarcis siculus seems to be a good bioindicator in ecotoxicological studies and potentially in risk assessment of pesticides, although further analyses in laboratory and in the field are needed to achieve more accurate quantification of specific pesticide effects in relation to known exposure history and to understand if other mechanisms were involved in the toxicity and detoxification process of pesticides for this species.

The paper presents a review of literature data, supplemented with original observations, on the presence, establishment, distribution and invasive status of alien fish, amphibian and reptile species in Romania. Consistent criteria were followed in defining alien species records, establishment and invasive status. From the 48 alien fish species, 1 fish hybrid, 1 amphibian and 18 reptile species recorded, only 16 fishes and 3 reptiles can be regarded as established. Of these we consider the criteria for invasive status as being probably fulfilled by one fish species (Perccottus glenii), and less likely by six more fish species. The presence and the alien status of the one amphibian are debatable. No reptile species can be considered invasive at present.

Finger length ratios are organized during embryonic development of fingers as they exposed to sex steroid hormones, and may show varying degrees of sexual dimorphism between males and females in different animal groups. Among all the finger length ratios calculated in a sample, the ratio between the second to fourth fingers (2D: 4D) is the most important one. In this study, the 2D:4D ratios in both sides of the body (right and left) in all limbs were investigated to determine if sexual dimorphism is present in the 2D: 4D ratios in 44 specimens studied (20 males and 24 females) of Acanthodactylus blanfordi. Other morphological traits of the two sexes were also examined (23 metric and meristic traits), as a result, sexual dimorphism was observed in five metric and meristic morphological traits. In terms of the ratio of the size of the fingers and toes, sexual dimorphism in the length of the fingers was observed only in 2D: 4D on the right side of the body in forelimbs and hindlimbs. The value of this trait was higher in males than females and this difference was statistically significant P ≤0.05).

Background Reptiles form a paraphyletic group with significant roles for human society, including species that are considered important for food, medicinal and mystical use and as pets. Some species are considered to be aversive, whereas others are captivating among people. Aversion is an important factor which should be considered in the conservation policies of these animals. As such, here, we investigate the demographic, educational, perceptives and behavioural factors of students related to their aversion and non-conservationist attitudes directed towards different reptile species and evaluated the effect of educational exhibition of animals as a strategy of mitigating these attitudes. Methods The data were obtained through forms on the aversion and conservation of reptiles represented by three species, a chelonian, a snake and a lizard. The form was given in two instances, before and after a visit to a private zoo (Museu Vivo Répteis da Caatinga), where the students had contact with the aforementioned species. A total of 133 students participated in the study, among these, 43 from elementary school (21 females and 22 males), 29 from high school (16 females and 13 males), 37 from university biology students (22 females and 15 males) and 24 university mathematics students (6 females and 18 males). Results Among all evaluated species, snakes were considered to be the most aversive species. The aversion attitudes differed between the three evaluated species when correlated to age and type of university courses. However, this pattern did not differ between student sexes. Older students had a lower aversion to the chelonian compared to the younger ones, but for snakes and lizards, the aversion was high among students of all ages. The university biology students had a lower aversion compared to the university mathematics students for the three species. The recognition and handle of the tested species and previous visits to educational exhibitions of animals were negatively related to aversion. The comparative analysis of the forms applied before and after the visit to the Museu Vivo Répteis da Caatinga showed that this visit influenced the decrease of aversion, but not in non-conservationist attitudes, for which the attitude scores had always been low. Conclusions We conclude that reptile aversion varies in accordance with the taxon, being snakes the most disliked by students. The visit to the educational exhibition of animals contributed to the reduction of the observed aversion. This is especially true when the acquisition of educational information about species is associated with practical activities which includes contact with the animals. Finally, the fact that non-conservationist attitudes had been low towards all species perhaps demonstrates a conservationist tendency even for the most aversive species.

Animals often exhibit distinct microbial communities when maintained in captivity as compared to when in the wild. Such differentiation may be significant in headstart and reintroduction programs where individuals spend some time in captivity before release into native habitats. Using 16S rRNA gene sequencing, we (i) assessed differences in gut microbial communities between captive and wild Fijian crested iguanas (Brachylophus vitiensis) and (ii) resampled gut microbiota in captive iguanas released onto a native island to monitor microbiome restructuring in the wild. We used both cloacal swabs and fecal samples to further increase our understanding of gut microbial ecology in this IUCN Critically Endangered species. We found significant differentiation in gut microbial community composition and structure between captive and wild iguanas in both sampling schemes. Approximately two months postrelease, microbial communities in cloacal samples from formerly captive iguanas closely resembled wild counterparts. Interestingly, microbial communities in fecal samples from these individuals remained significantly distinct from wild conspecifics. Our results indicate that captive upbringings can lead to differences in microbial assemblages in headstart iguanas as compared to wild individuals even after host reintroduction into native conditions. This investigation highlights the necessity of continuous monitoring of reintroduced animals in the wild to ensure successful acclimatization and release., We show that captivity impacts gut microbial assemblages in headstart animals compared with wild individuals long after host reintroduction into native conditions. This advances our understanding of microbiome diversity and evolution in a Critically Endangered reptile and shows how captivity influences the microbiome of reptiles in general.

Marine reptiles and mammals are phylogenetically so distant from each other that their marine adaptations are rarely compared directly. We reviewed ecophysiological features in extant non-avian marine tetrapods representing 31 marine colonizations to test whether there is a common pattern across higher taxonomic groups, such as mammals and reptiles. Marine adaptations in tetrapods can be roughly divided into aquatic and haline adaptations, each of which seems to follow a sequence of three steps. In combination, these six categories exhibit five steps of marine adaptation that apply across all clades except snakes: Step M1, incipient use of marine resources; Step M2, direct feeding in the saline sea; Step M3, water balance maintenance without terrestrial fresh water; Step M4, minimized terrestrial travel and loss of terrestrial feeding; and Step M5, loss of terrestrial thermoregulation and fur/plumage. Acquisition of viviparity is not included because there is no known case where viviparity evolved after a tetrapod lineage colonized the sea. A similar sequence is found in snakes but with the haline adaptation step (Step M3) lagging behind aquatic adaptation (haline adaptation is Step S5 in snakes), most likely because their unique method of water balance maintenance requires a supply of fresh water. The same constraint may limit the maximum body size of fully marine snakes. Steps M4 and M5 in all taxa except snakes are associated with skeletal adaptations that are mechanistically linked to relevant ecophysiological features, allowing assessment of marine adaptation steps in some fossil marine tetrapods. We identified four fossil clades containing members that reached Step M5 outside of stem whales, pinnipeds, sea cows and sea turtles, namely Eosauropterygia, Ichthyosauromorpha, Mosasauroidea, and Thalattosuchia, while five other clades reached Step M4: Saurosphargidae, Placodontia, Dinocephalosaurus, Desmostylia, and Odontochelys. Clades reaching Steps M4 and M5, both extant and extinct, appear to have higher species diversity than those only reaching Steps M1 to M3, while the total number of clades is higher for the earlier steps. This suggests that marine colonizers only diversified greatly after they minimized their use of terrestrial resources, with many lineages not reaching these advanced steps. Historical patterns suggest that a clade does not advance to Steps M4 and M5 unless these steps are reached early in the evolution of the clade. Intermediate forms before a clade reached Steps M4 and M5 tend to become extinct without leaving extant descendants or fossil evidence. This makes it difficult to reconstruct the evolutionary history of marine adaptation in many clades. Clades that reached Steps M4 and M5 tend to last longer than other marine tetrapod clades, sometimes for more than 100 million years.