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1.
Braz. j. biol ; 84: e249617, 2024. graf
Artigo em Inglês | MEDLINE, LILACS, VETINDEX | ID: biblio-1345540

RESUMO

Abstract Hibernation is a natural condition of animals that lives in the temperate zone, although some tropical lizards also experience hibernation annually, such as the lizard native from South America, Salvator merianae, or "tegu" lizard. Even though physiological and metabolic characteristic associated with hibernation have been extensively studied, possible alterations in the red blood cells (RBC) integrity during this period remains unclear. Dehydration and fasting are natural consequences of hibernating for several months and it could be related to some cellular modifications. In this study, we investigated if the osmotic tolerance of RBCs of tegu lizard under hibernation is different from the cells obtained from animals while normal activity. Additionally, we indirectly investigated if the RBCs membrane of hibernating tegus could be associated with oxidation by quantifying oxidized biomolecules and the activity of antioxidant enzymes. Our findings suggest that RBCs are more fragile during the hibernation period, although we did not find evidence of an oxidative stress scenario associated with the accentuated fragility. Even though we did not exclude the possibility of oxidative damage during hibernation, we suggested that an increased RBCs volume as a consequence of hypoosmotic blood during hibernation could also affect RBCs integrity as noted.


Resumo A hibernação é uma condição natural dos animais que vivem na zona temperada, embora alguns lagartos tropicais também experenciem hibernação anualmente, como é o caso do lagarto nativo da América do Sul, Salvator merianae ou "teiú". Embora as características fisiológicas e metabólicas associadas à hibernação tenham sido amplamente estudadas, possíveis alterações na integridade das hemácias durante esse período ainda permanecem obscuras. A desidratação e o jejum são consequências naturais da hibernação por vários meses e podem estar relacionadas a algumas modificações celulares. Neste estudo, investigamos se a tolerância osmótica de hemácias do lagarto teiú sob hibernação são diferentes das células obtidas de animais em atividade normal. Além disso, investigamos indiretamente por meio da quantificação de biomoléculas oxidadas e da atividade de enzimas antioxidantes se a membrana das hemácias dos teiús em hibernação poderia estar associada à oxidação. Nossos resultados sugerem que as hemácias possuem maior fragilidade durante o período de hibernação, embora não tenhamos encontrado evidências de um cenário de estresse oxidativo associado à essa fragilidade acentuada. Embora não tenhamos excluído a possibilidade de dano oxidativo durante a hibernação, sugerimos que um aumento no volume das hemácias como consequência de sangue hipoosmótico durante a hibernação também poderia afetar a integridade de hemácias, tal como foi observado.


Assuntos
Animais , Hibernação , Lagartos , Oxirredução , Estresse Oxidativo , Eritrócitos
2.
Braz. j. biol ; 84: e254253, 2024. tab, graf
Artigo em Inglês | MEDLINE, LILACS, VETINDEX | ID: biblio-1350308

RESUMO

Abstract During the present study, specimens were collected from selected sites of Cholistan desert and Kalabagh Game Reserve, Punjab province, Pakistan. Each captured specimen was tagged with voucher number and morphometric measurements were taken. The average snout to vent length was 172.559±1.40 mm and average weight was 92.1±1.30 g. The DNA of Uromastyx hardwickii was amplified and sequenced using 16S rRNA primer set. The obtained DNA sequence has shown reliable and clear species identification. After trimming ambiguous bases, the obtained 16S rRNA fragment was 520 bp while 16S rRNA fragments aligned with closely matched sequence from NCBI comprised of 510 bp. Closely matched sequences of genus Uromastyx were retrieved from NCBI in blast searches. Neighbour-joining tree of genus Uromastyx was constructed based on p-distance using MEGA X. The mean intraspecific variation was 0.095±0.01 while intraspecific variation was ranging from 0-1%. Similarly, interspecific variation of Uromastyx hardwikii with Saara asmussi, Uromastyx alfredschmidti, Uromastyx geyri, Uromastyx thomasi, Uromastyx alfredschmidti was 0-12%, 0-19%, 0-19%, 0-20%, 12-19% respectively. The newly produced DNA was submitted to NCBI and accession number was obtained (MW052563.1). Results of current study provided information about the molecular and morphological identification of Genus Uromastyx. In our recommendation, comprehensive molecular based identification of Pakistan's reptiles is required to report any new or subspecies from country.


Resumo Durante o presente estudo, os espécimes foram coletados em locais selecionados do deserto do Cholistan e da Reserva de Caça de Kalabagh, província de Punjab, Paquistão. Cada espécime capturado foi etiquetado com o número do comprovante e medidas morfométricas foram realizadas. O comprimento médio do focinho à cloaca foi de 172,559 ± 1,40 mm, e o peso médio foi de 92,1 ± 1,30 g. O DNA de Uromastyx hardwickii foi amplificado e sequenciado usando o conjunto de primer 16S rRNA. A sequência de DNA obtida mostrou identificação de espécies confiável e clara. Após o corte de bases ambíguas, o fragmento de rRNA 16S obtido tinha 520 pb, enquanto os fragmentos de rRNA 16S alinhados com a sequência próxima do NCBI composta por 510 pb. Sequências semelhantes do gênero Uromastyx foram recuperadas do NCBI em pesquisas de explosão. A árvore de união de vizinhos do gênero Uromastyx foi construída com base na distância-p usando MEGA X. A variação intraespecífica média foi de 0,095 ± 0,01, enquanto a variação intraespecífica foi de 0-1%. Da mesma forma, a variação interespecífica de Uromastyx hardwikii com Saara asmussi, Uromastyx alfredschmidti, Uromastyx geyri, Uromastyx thomasi, Uromastyx alfredschmidti foi de 0-12%, 0-19%, 0-19%, 0-20%, 12-19%, respectivamente. O DNA recém-produzido foi submetido ao NCBI e o número de acesso foi obtido (MW052563.1). Os resultados do estudo atual forneceram informações sobre a identificação molecular e morfológica do Gênero Uromastyx. Em nossa recomendação, a identificação de base molecular abrangente de répteis do Paquistão é necessária para relatar qualquer nova ou subespécie do país.


Assuntos
Animais , Lagartos , Paquistão , Filogenia , Variação Genética/genética , RNA Ribossômico 16S
4.
Elife ; 112022 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-35502582

RESUMO

The squamates (lizards, snakes, and relatives) today comprise more than 10,000 species, and yet their sister group, the Rhynchocephalia, is represented by a single species today, the tuatara. The explosion in squamate diversity has been tracked back to the Cretaceous Terrestrial Revolution, 100 million years ago (Ma), the time when flowering plants began their takeover of terrestrial ecosystems, associated with diversification of coevolving insects and insect-eating predators such as lizards, birds, and mammals. Squamates arose much earlier, but their long pre-Cretaceous history of some 150 million years (Myr) is documented by sparse fossils. Here, we provide evidence for an initial radiation of squamate morphology in the Middle and Late Jurassic (174-145 Ma), and show that they established their key ecological roles much earlier than had been assumed, and they have not changed them much since.


Assuntos
Ecossistema , Lagartos , Animais , Evolução Biológica , Fósseis , Insetos , Lagartos/anatomia & histologia , Mamíferos , Filogenia
5.
J Evol Biol ; 35(5): 680-692, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35535762

RESUMO

Animal signals evolve in an ecological context. Locally adapting animal sexual signals can be especially important for initiating or reinforcing reproductive isolation during the early stages of speciation. Previous studies have demonstrated that dewlap colour in Anolis lizards can be highly variable between populations in relation to both biotic and abiotic adaptive drivers at relatively large geographical scales. Here, we investigated differentiation of dewlap coloration among habitat types at a small spatial scale, within multiple islands of the West Indies, to test the hypothesis that similar local adaptive processes occur over smaller spatial scales. We explored variation in dewlap coloration in the most widespread species of anole, Anolis sagrei, across three characteristic habitats spanning the Bahamas and the Cayman Islands, namely beach scrub, primary coppice forest and mangrove forest. Using reflectance spectrometry paired with supervised machine learning, we found significant differences in spectral properties of the dewlap between habitats within small islands, sometimes over very short distances. Passive divergence in dewlap phenotype associated with isolation-by-distance did not seem to explain our results. On the other hand, these habitat-specific dewlap differences varied in magnitude and direction across islands, and thus, our primary test for adaptation-parallel responses across islands-was not supported. We suggest that neutral processes or selection could be involved in several ways, including sexual selection. Our results shed new light on the scale at which signal colour polymorphism can be maintained in the presence of gene flow, and the relative role of local adaptation and other processes in driving these patterns of dewlap colour variation across islands.


Assuntos
Lagartos , Animais , Cor , Ecossistema , Fluxo Gênico , Lagartos/genética , Índias Ocidentais
6.
J Exp Biol ; 225(7)2022 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-35363854

RESUMO

The venom glands of reptiles, particularly those of front-fanged advanced snakes, must satisfy conflicting biological demands: rapid synthesis of potentially labile and highly toxic proteins, storage in the gland lumen for long periods, stabilization of the stored secretions, immediate activation of toxins upon deployment and protection of the animal from the toxic effects of its own venom. This dynamic system could serve as a model for the study of a variety of different phenomena involving exocrine gland activation, protein synthesis, stabilization of protein products and secretory mechanisms. However, these studies have been hampered by a lack of a long-term model that can be propagated in the lab (as opposed to whole-animal studies). Numerous attempts have been made to extend the lifetime of venom gland secretory cells, but only recently has an organoid model been shown to have the requisite qualities of recapitulation of the native system, self-propagation and long-term viability (>1 year). A tractable model is now available for myriad cell- and molecular-level studies of venom glands, protein synthesis and secretion. However, venom glands of reptiles are not identical, and many differ very extensively in overall architecture, microanatomy and protein products produced. This Review summarizes the similarities among and differences between venom glands of helodermatid lizards and of rear-fanged and front-fanged snakes, highlighting those areas that are well understood and identifying areas where future studies can fill in significant gaps in knowledge of these ancient, yet fascinating systems.


Assuntos
Lagartos , Venenos de Serpentes , Animais , Glândulas Exócrinas/metabolismo , Lagartos/metabolismo , Glândulas Salivares/metabolismo , Venenos de Serpentes/metabolismo , Serpentes
7.
Parasit Vectors ; 15(1): 116, 2022 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-35365181

RESUMO

BACKGROUND: The genus Cissophyllus (Cosmocercoidea: Kathlaniidae) is a rare group of nematodes parasitic in turtles and lizards. To date, only four species have been reported in Asia and North America. However, most of them are inadequately described. The species Cissophyllus leytensis has never been reported since it was originally described by Tubangui and Villaamil in 1933 from the Philippine sailfin lizard Hydrosaurus pustulatus (Eschscholtz, 1829) (Reptilia: Squamata). Furthermore, the systematic status of Cissophyllus/Cissophyllinae in the family Kathlaniidae of the superfamily Cosmocercoidea remains under debate. METHODS: The detailed morphology of C. leytensis was studied using light microscopy (LM) and, for the first time, scanning electron microscopy (SEM), based on newly collected specimens from the type host H. pustulatus. Six different genetic markers, including nuclear sequences [small ribosomal subunit (18S), internal transcribed spacer (ITS) and large ribosomal subunit (28S)], plus mitochondrial genes [cytochrome c oxidase subunit 1 (cox1), cytochrome c oxidase subunit 2 (cox2) and 12S small subunit ribosomal RNA gene] of C. leytensis were sequenced. Additionally, in order to test the validity of the subfamily Cissophyllinae and clarify the phylogenetic relationships of Cissophyllus and the other genera in the family Kathlaniidae, phylogenetic analyses based on 18S + 28S and ITS sequence data were performed using maximum likelihood (ML) and Bayesian inference (BI) analyses, respectively. RESULTS: Our observations using LM and SEM revealed some previously unreported morphological features, necessitating the redescription of this poorly known species. The presence of remarkable morphological variation in the isthmus and the position of excretory pore among different individuals was found. Molecular analysis showed no intraspecific nucleotide divergence detected in the 18S, ITS, 28S, cox2 and 12S regions among different individuals of C. leytensis, but a low level of intraspecific genetic variation was found in the cox1 (0.52%). Our phylogenetic results showed the representatives of the Cosmocercoidea divided into four large clades (Cosmocerca + Aplectana + Cosmocercoides representing the family Cosmocercidae, Cruzia representing the subfamily Cruzinae of Kathlaniidae, Falcaustra + Cissophyllus + Megalobatrachonema representing the subfamily Kathlaniinae of Kathlaniidae, and Orientatractis + Rondonia representing the family Atractidae). The genus Cissophyllus clustered together with the genus Megalobatrachonema in both the ML and BI trees using ITS sequence data, but displayed a sister relationship to the genus Falcaustra in the ML tree and to the genera Falcaustra + Megalobatrachonema in the BI tree using 18S + 28S sequence data. CONCLUSIONS: Molecular phylogenetic results further confirmed that the family Kathlaniidae is not a monophyletic group. The subfamily Cruziinae should be moved from the hitherto-defined family Kathlaniidae and elevated as a separate family Cruziidae. The present phylogenetic results also negated the validity of the subfamily Cissophyllinae and supported the genus Cissophyllus assigned in the subfamily Kathlaniinae. Molecular analysis indicated that the morphological variation in the isthmus and position of excretory pore among different individuals should be considered as intraspecific variation. Moreover, some characters important for the specific diagnosis of C. leytensis are reported for the first time: the number of acuminate denticles (lamellae) on each lip, the chitinized pharynx with three flabellate pharyngeal plates, the presence of single medioventral precloacal papilla and the detailed morphology of caudal papillae. The present study is only the second record of C. leytensis.


Assuntos
Ascaridídios , Lagartos , Nematoides , Parasitos , Animais , Ascaridídios/anatomia & histologia , Teorema de Bayes , Filipinas , Filogenia
8.
Mol Biol Evol ; 39(4)2022 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-35388432

RESUMO

The repeated evolution of the same traits in distantly related groups (convergent evolution) raises a key question in evolutionary biology: do the same genes underpin convergent phenotypes? Here, we explore one such trait, viviparity (live birth), which, qualitative studies suggest, may indeed have evolved via genetic convergence. There are >150 independent origins of live birth in vertebrates, providing a uniquely powerful system to test the mechanisms underpinning convergence in morphology, physiology, and/or gene recruitment during pregnancy. We compared transcriptomic data from eight vertebrates (lizards, mammals, sharks) that gestate embryos within the uterus. Since many previous studies detected qualitative similarities in gene use during independent origins of pregnancy, we expected to find significant overlap in gene use in viviparous taxa. However, we found no more overlap in uterine gene expression associated with viviparity than we would expect by chance alone. Each viviparous lineage exhibits the same core set of uterine physiological functions. Yet, contrary to prevailing assumptions about this trait, we find that none of the same genes are differentially expressed in all viviparous lineages, or even in all viviparous amniote lineages. Therefore, across distantly related vertebrates, different genes have been recruited to support the morphological and physiological changes required for successful pregnancy. We conclude that redundancies in gene function have enabled the repeated evolution of viviparity through recruitment of different genes from genomic "toolboxes", which are uniquely constrained by the ancestries of each lineage.


Assuntos
Lagartos , Viviparidade não Mamífera , Animais , Evolução Biológica , Feminino , Genômica , Lagartos/genética , Mamíferos/fisiologia , Placenta , Gravidez , Viviparidade não Mamífera/genética
9.
Molecules ; 27(7)2022 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-35408771

RESUMO

Proteins are ubiquitous macromolecules that display a vast repertoire of chemical and enzymatic functions, making them suitable candidates for chemosignals, used in intraspecific communication. Proteins are present in the skin gland secretions of vertebrates but their identity, and especially, their functions, remain largely unknown. Many lizard species possess femoral glands, i.e., epidermal organs primarily involved in the production and secretion of chemosignals, playing a pivotal role in mate choice and intrasexual communication. The lipophilic fraction of femoral glands has been well studied in lizards. In contrast, proteins have been the focus of only a handful of investigations. Here, we identify and describe inter-individual expression patterns and the functionality of proteins present in femoral glands of male sand lizards (Lacerta agilis) by applying mass spectrometry-based proteomics. Our results show that the total number of proteins varied substantially among individuals. None of the identified femoral gland proteins could be directly linked to chemical communication in lizards, although this result hinges on protein annotation in databases in which squamate semiochemicals are poorly represented. In contrast to our expectations, the proteins consistently expressed across individuals were related to the immune system, antioxidant activity and lipid metabolism as their main functions, showing that proteins in reptilian epidermal glands may have other functions besides chemical communication. Interestingly, we found expression of the Major Histocompatibility Complex (MHC) among the multiple and diverse biological processes enriched in FGs, tentatively supporting a previous hypothesis that MHC was coopted for semiochemical function in sand lizards, specifically in mate recognition. Our study shows that mass spectrometry-based proteomics are a powerful tool for characterizing and deciphering the role of proteins secreted by skin glands in non-model vertebrates.


Assuntos
Lagartos , Animais , Humanos , Sistema Imunitário/metabolismo , Metabolismo dos Lipídeos , Lagartos/metabolismo , Masculino , Feromônios/metabolismo , Proteômica
10.
Sci Rep ; 12(1): 7051, 2022 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-35488011

RESUMO

Many lizard species use caudal autotomy, the ability to self-amputate a portion of the tail, as an effective but costly survival strategy. However, as a lizard grows, its increased size may reduce predation risk allowing for less costly strategies (e.g., biting and clawing) to be used as the primary defence. The King's skink (Egernia kingii) is a large scincid up to approximately 244 mm snout to vent length (SVL) in size when adult. Adults rely less on caudal autotomy than do juveniles due to their size and strength increase during maturation. It has been hypothesised that lower behavioural reliance on autotomy in adults is reflected in loss or restriction of caudal vertebrae fracture planes through ossification as caudal intra-vertebral fracture planes in some species ossify during ontogenetic growth. To test this, we used micro-CT to image the tails of a growth series of seven individuals of E. kingii. We show that fracture planes are not lost or restricted ontogenetically within E. kingii, with adults retaining between 39-44 autotomisable vertebrae following 5-6 non-autotomisable vertebrae. Even though mature E. kingii rely less on caudal autotomy than do juveniles, this research shows that they retain the maximum ability to autotomise their tails, providing a last resort option to avoid threats. The potential costs associated with retaining caudal autotomy are most likely mitigated through neurological control of autotomy and E. kingii's longevity.


Assuntos
Lagartos , Animais , Humanos , Comportamento Predatório
11.
Oecologia ; 198(4): 905-915, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35419647

RESUMO

Increasing trends in environmental temperatures and changes in the hydrological cycle caused by climate change are affecting organisms around the world. Water balance is an important feature of organisms as warmer and drier environments increase water vapour pressure deficit and cutaneous water loss. The aim of our study was to understand the hourly kinetics of losses under water-restricted conditions. In general, these kinetics are thought to be negligible, and values from water loss studies have often been summed or averaged for population and species comparisons. We compiled a cross-species data set of instantaneous water loss (EWLi) of lizards in which weight was recorded every hour for 12 h (a period considered ecologically relevant for lizards) under standardized conditions with minimal disturbance. We statistically tested whether the duration of the experiment affected the values and found that the duration affected 83% of the data sets. In most cases, water loss was significantly higher during the first hour. This is likely a result of increased activity due to acclimation to the experimental conditions. However, as the experiment progressed, other temporal patterns of EWLi occurred that were not consistent between species. In addition, the average value and the first and last values of EWLi changed significantly for most species as the experiment progressed. These results suggest that the hourly kinetics of water loss should not be ignored, while experimental procedures in which EWL is recorded continuously rather than only at the beginning and end of the experiment should be used to find finer temporal variations.


Assuntos
Lagartos , Aclimatação , Animais , Mudança Climática , Temperatura , Equilíbrio Hidroeletrolítico
12.
J Exp Biol ; 225(8)2022 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-35363299

RESUMO

Animals rely on their ability to perform certain tasks sufficiently well to survive, secure mates and reproduce. Performance traits depend on morphology, and so morphological traits should predict performance, yet this relationship is often confounded by multiple competing performance demands. Males and females experience different selection pressures on performance, and the consequent sexual conflict over performance expression can either constrain performance evolution or drive sexual dimorphism in both size and shape. Furthermore, change in a single morphological trait may benefit some performance traits at the expense of others, resulting in functional trade-offs. Identifying general or sex-specific relationships between morphology and performance at the organismal level thus requires a multivariate approach, as individuals are products of both an integrated phenotype and the ecological environment in which they have developed and evolved. We estimated the multivariate morphology→performance gradient in wild-caught, green anoles (Anolis carolinensis) by measuring external morphology and forelimb and hindlimb musculature, and mapping these morphological traits to seven measured performance traits that cover the broad range of ecological challenges faced by these animals (sprint speed, endurance, exertion distance, climbing power, jump power, cling force and bite force). We demonstrate that males and females differ in their multivariate mapping of traits on performance, indicating that sex-specific ecological demands likely shape these relationships, but do not differ in performance integration.


Assuntos
Lagartos , Animais , Evolução Biológica , Força de Mordida , Feminino , Membro Anterior , Membro Posterior/anatomia & histologia , Lagartos/anatomia & histologia , Masculino , Caracteres Sexuais
13.
Am Nat ; 199(5): 719-728, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35472020

RESUMO

AbstractThe scarcity of asexual reproduction in vertebrates alludes to an inherent cost. Several groups of asexual vertebrates exhibit lower endurance capacity (a trait predominantly sourced by mitochondrial respiration) compared with congeneric sexual species. Here we measure endurance capacity in five species of Aspidoscelis lizards and examine mitochondrial respiration between sexual and asexual species using mitochondrial respirometry. Our results show reduced endurance capacity, reduced mitochondrial respiration, and reduced phenotypic variability in asexual species compared with parental sexual species, along with a positive relationship between endurance capacity and mitochondrial respiration. Results of lower endurance capacity and lower mitochondrial respiration in asexual Aspidoscelis are consistent with hypotheses involving mitonuclear incompatibility.


Assuntos
Lagartos , Animais , Partenogênese , Fenótipo , Reprodução Assexuada , Respiração
14.
Am Nat ; 199(5): 666-678, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35472022

RESUMO

AbstractTraits often contribute to multiple functions, complicating our understanding of the selective pressures that influence trait evolution. In the Chihuahuan Desert, predation is thought to be the primary driver of cryptic light coloration in three White Sands lizard species relative to the darker coloration of populations on adjacent dark soils. However, coloration also influences radiation absorption and thus animal body temperatures. We combined comparative physiological experiments and biophysical models to test for thermal consequences of evolving different color morphs in White Sands across the three species. While light and dark morphs have not evolved different physiological heat limits within species, differences in radiation absorption between morphs lead to body temperature differences that impact relative overheating risk and activity patterns. Moreover, for all three species, an idealized morph that matches the White Sands substrate would have considerably less activity time, by approximately 1 month, than existing light morphs. Overall, there are both benefits and costs to greater substrate matching, the balance of which may prevent the evolution of optimal crypsis. Our work highlights the importance of color in dictating thermal performance and the complexity inherent in understanding the evolution of coloration.


Assuntos
Lagartos , Animais , Temperatura Corporal , Cor , Análise Custo-Benefício , Pigmentação/fisiologia , Comportamento Predatório
15.
J Evol Biol ; 35(5): 708-718, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35384114

RESUMO

Blood oxygen-carrying capacity is shaped both by the ambient oxygen availability as well as species-specific oxygen demand. Erythrocytes are a critical part of oxygen transport and both their size and shape can change in relation to species-specific life-history, behavioural or ecological conditions. Here, we test whether components of the environment (altitude), life history (reproductive mode, body temperature) and behaviour (diving, foraging mode) drive erythrocyte size variation in the Lepidosauria (lizards, snakes and rhynchocephalians). We collected data on erythrocyte size (area) and shape (L/W: elongation ratio) from Lepidosauria across the globe (N = 235 species). Our analyses show the importance of oxygen requirements as a driver of erythrocyte size. Smaller erythrocytes were associated with the need for faster delivery (active foragers, high-altitude species, warmer body temperatures), whereas species with greater oxygen demands (diving species, viviparous species) had larger erythrocytes. Erythrocyte size shows considerable cross-species variation, with a range of factors linked to the oxygen delivery requirements being major drivers of these differences. A key future aspect for study would include within-individual plasticity and how changing states, for example, pregnancy, perhaps alter the size and shape of erythrocytes in Lepidosaurs.


Assuntos
Lagartos , Viviparidade não Mamífera , Animais , Eritrócitos , Oviparidade , Oxigênio , Serpentes
16.
BMC Genomics ; 23(1): 322, 2022 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-35459109

RESUMO

BACKGROUND: In some vertebrate species, gene-environment interactions can determine sex, driving bipotential gonads to differentiate into either ovaries or testes. In the central bearded dragon (Pogona vitticeps), the genetic influence of sex chromosomes (ZZ/ZW) can be overridden by high incubation temperatures, causing ZZ male to female sex reversal. Previous research showed ovotestes, a rare gonadal phenotype with traits of both sexes, develop during sex reversal, leading to the hypothesis that sex reversal relies on high temperature feminisation to outcompete the male genetic cue. To test this, we conducted temperature switching experiments at key developmental stages, and analysed the effect on gonadal phenotypes using histology and transcriptomics. RESULTS: We found sexual fate is more strongly influenced by the ZZ genotype than temperature. Any exposure to low temperatures (28 °C) caused testes differentiation, whereas sex reversal required longer exposure to high temperatures. We revealed ovotestes exist along a spectrum of femaleness to male-ness at the transcriptional level. We found inter-individual variation in gene expression changes following temperature switches, suggesting both genetic sensitivity to, and the timing and duration of the temperature cue influences sex reversal. CONCLUSIONS: These findings bring new insights to the mechanisms underlying sex reversal, improving our understanding of thermosensitive sex systems in vertebrates.


Assuntos
Lagartos , Animais , Feminino , Gônadas , Lagartos/genética , Masculino , Cromossomos Sexuais , Processos de Determinação Sexual/genética , Diferenciação Sexual/genética , Temperatura
17.
Zootaxa ; 5124(4): 401-430, 2022 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-35391113

RESUMO

Here we provide the first phylogenetic analysis that include Afrogecko ansorgii and a detailed morphological comparison with other species of leaf-toed geckos. For this purpose, we used two mitochondrial (16S, ND2) and four nuclear (RAG1, RAG2, CMOS, PDC) genes to produce a robust phylogenetic reconstruction. This allowed us to show that A. ansorgii is not related as previously believed to circum-Indian Ocean leaf-toed geckos and is rather more closely related to other Malagasy leaf-toed geckos. Additionally, we explore and compare osteological variation in A. ansorgii skulls through High Resolution X-ray Computed Tomography with previously published material. This allowed us to describe herein a new genus, Bauerius gen. nov., and additionally provide a detailed redescription of the species (including the first description of male material), supplementing the limited original description and type series, which consisted of only two females.


Assuntos
Lagartos , Angola , Animais , Núcleo Celular/genética , Lagartos/genética , Masculino , Mitocôndrias , Filogenia
19.
Zootaxa ; 5120(3): 449-450, 2022 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-35391155

RESUMO

Body size is perhaps the most important trait for organism biologists, as it is associated with a myriad of ecological, evolutionary, behavioral, morphological, physiological and life-history aspects (e.g., rates of molecular evolution, metabolic rates, predation, reproduction), and with extinction risk. There are, however, several measures commonly used to quantify organism body size. Within ectothermic tetrapods, the most common measures include snout-vent length (SVL, mostly in lizards), and total length (TL, in most snakes). In endotherms, however, and especially in mammals, body mass is the most common measure of size.


Assuntos
Lagartos , Répteis , Anfíbios , Animais , Tamanho Corporal , Mamíferos/anatomia & histologia , Répteis/anatomia & histologia , Serpentes
20.
Zootaxa ; 5120(3): 409-422, 2022 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-35391159

RESUMO

Bronchocela hayeki (Mller, 1928) is one of the rarest species of the genus, known only from a handful of museum specimens from five locations in North Sumatra, and often confused with its similar congener, B. cristatella, which occurs widely throughout the Indonesian Archipelago and Peninsular Malaysia. Here, we examined the morphology of B. hayeki based on museum specimens, and redescribe the species based on a freshly collected series near the type locality, as the condition of its neotype is not in a good state. We studied the characters of B. hayeki with a morphometric comparison to its sympatric congener B. cristatella and allopatric congener, B. jubata from Sumatra Island, Indonesia. Based on the current distribution pattern and the apparent threats, we update the conservation status of B. hayeki using IUCN Red List Criteria and propose that it be considered as an Endangered (EN) species endemic of northern Sumatra including Aceh. We also provide a key to the recognized Bronchocela species, based on examined material and literature.


Assuntos
Briozoários , Lagartos , Animais , Espécies em Perigo de Extinção , Indonésia , Árvores
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