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PeerJ 2023Many temperate reptiles survive winter by using subterranean refugia until external conditions become suitable for activity. Determining when to emerge from refugia...
Many temperate reptiles survive winter by using subterranean refugia until external conditions become suitable for activity. Determining when to emerge from refugia relies on the ability to interpret when above-ground environmental conditions are survivable. If temperate reptiles rely on specific environmental cues such as temperature to initiate emergence, we should expect emergence phenologies to be predictable using local climatic data. However, specific predictors of emergence for many temperate reptiles, including the Timber Rattlesnake (), remain unclear, limiting our understanding of their overwintering phenology and restricting effective conservation and management. Our objectives were to identify environmental cues of spring emergence for in Illinois to determine the species' emergence phenology, and to examine the applicability of identified cues in predicting emergence phenology across the species' range. We used wildlife cameras and weather station-derived environmental data to observe and predict the daily surface presence of throughout the late winter and early spring at communal refugia in west-central and northern Illinois. The most parsimonious model for predicting surface presence included the additive effects of maximum daily temperature, accumulated degree days, and latitude. With a notable exception in the southeastern U.S., the model accurately predicted the average emergence day for eight other populations range wide, emphasizing the importance of temperature in influencing the phenological plasticity observed across the species' range. The apparent broad applicability of the model to other populations suggests it can be a valuable tool in predicting spring emergence phenology. Our results provide a foundation for further ecological enquiries and improved management and conservation strategies.
Topics: Animals; Crotalus; Seasons; Temperature; Animals, Wild; Reptiles
PubMed: 37780371
DOI: 10.7717/peerj.16044 -
Frontiers in Cellular and Infection... 2023The Chinese soft-shelled turtle () has become increasingly susceptible to frequent diseases with the intensification of farming, which severely impacts the development...
The Chinese soft-shelled turtle () has become increasingly susceptible to frequent diseases with the intensification of farming, which severely impacts the development of the aquaculture industry. Sodium butyrate (SB) is widely used as a feed additive due to its promotion of growth, enhancement of immune function, and antioxidative properties. This study aimed to investigate the effects of dietary SB on the growth performance, immune function, and intestinal microflora of Chinese soft-shelled turtles. A total of 300 Chinese soft-shelled turtles (mean weight: 11.36 ± 0.21g) were randomly divided into four groups with three parallel sets in each group. Each group was fed a diet supplemented with 0%, 0.005%, 0.01%, or 0.02% SB for 60 days. The results demonstrated an upward trend in weight gain rate (WGR) and specific growth rate (SGR) with increasing SB supplementation, and the experimental group fed with 0.02% SB showed a significant increase in WGR and SGR compared to other groups (< 0.05). These levels of SB also decreased the levels of feed conversion ratio (FCR) and the total cholesterol (TC) content of Chinese soft-shelled turtles, and the 0.02% SB was significantly lower than that of other groups (< 0.05). The activity of complement protein increased with increases in SB content, and the activities of complement C3 and C4 reached the highest level with 0.02% SB. The species abundance of the experimental group D fed with 0.02% SB was significantly higher than that of other groups ( 0.05). Furthermore, the relative abundance of 1 was significantly increased with 0.02% SB (< 0.05). In conclusion, adding 0.02% SB to the diet improves the growth performance, feed digestion ability, and intestinal microbiota of Chinese soft-shelled turtles.
Topics: Animals; Butyric Acid; Turtles; Gastrointestinal Microbiome; Sodium, Dietary; Diet; Immunity
PubMed: 37886667
DOI: 10.3389/fcimb.2023.1271912 -
Scientific Reports Oct 2023Ankylosaurs were important megaherbivores of Jurassic and Cretaceous ecosystems. Their distinctive craniodental anatomy and mechanics differentiated them from coexisting...
Ankylosaurs were important megaherbivores of Jurassic and Cretaceous ecosystems. Their distinctive craniodental anatomy and mechanics differentiated them from coexisting hadrosaurs and ceratopsians, and morphological evidence suggests dietary niche partitioning between sympatric ankylosaurids and nodosaurids. Here, we investigate the skull biomechanics of ankylosaurs relative to feeding function. First, we compare feeding functional performance between nodosaurids and ankylosaurids applying finite element analysis and lever mechanics to the skulls of Panoplosaurus mirus (Nodosauridae) and Euoplocephalus tutus (Ankylosauridae). We also compare jaw performance across a wider sample of ankylosaurs through lever mechanics and phylogenetic comparative methods. Mandibular stress levels are higher in Euoplocephalus, supporting the view that Panoplosaurus consumed tougher foodstuffs. Bite force and mechanical advantage (MA) estimates indicate that Panoplosaurus had a relatively more forceful and efficient bite than Euoplocephalus. There is little support for a role of the secondary palate in resisting feeding loads in the two ankylosaur clades. Several ankylosaurs converged on similar jaw mechanics, while some nodosaurids specialised towards high MA and some ankylosaurids evolved low MA jaws. Our study supports the hypothesis that ankylosaurs partitioned dietary niches in Late Cretaceous ecosystems and reveals that the two main ankylosaur clades evolved divergent evolutionary pathways in skull biomechanics and feeding habits.
Topics: Animals; Dinosaurs; Phylogeny; Ecosystem; Biomechanical Phenomena; Skull; Fossils; Feeding Behavior
PubMed: 37880323
DOI: 10.1038/s41598-023-45444-1 -
PeerJ 2023Sexual dimorphism in size and shape is widespread among squamate reptiles. Sex differences in snake skull size and shape are often accompanied by intersexual feeding...
BACKGROUND
Sexual dimorphism in size and shape is widespread among squamate reptiles. Sex differences in snake skull size and shape are often accompanied by intersexual feeding niche separation. However, allometric trajectories underlying these differences remain largely unstudied in several lineages. The sea krait (Serpentes: Elapidae) exhibits very clear sexual dimorphism in body size, with previous studies having reported females to be larger and to have a relatively longer and wider head. The two sexes also differ in feeding habits: males tend to prey in shallow water on muraenid eels, whereas females prey in deeper water on congerid eels.
METHODS
I investigated sexual dimorphism in skull shape and size as well as the pattern of skull growth, to determine whether males and females follow the same ontogenetic trajectories. I studied skull characteristics and body length in 61 male and female sea kraits.
RESULTS
The sexes differ in skull shape. Males and females follow distinct allometric trajectories. Structures associated with feeding performance are female-biased, whereas rostral and orbital regions are male-biased. The two sexes differ in allometric trajectories of feeding-related structures (female biased) that correspond to dietary divergence between the sexes.
CONCLUSIONS
Sea kraits exhibit clear sexual dimorphism in the skull form that may be explained by intersexual differences in the feeding habits as well as reproductive roles. The overall skull growth pattern resembles the typical pattern observed in other tetrapods.
Topics: Female; Male; Animals; Laticauda; Sex Characteristics; Elapidae; Colubrina; Skull; Hydrophiidae; Water
PubMed: 37868070
DOI: 10.7717/peerj.16266 -
The Science of the Total Environment Nov 2023PFAS contamination of urban waters is widespread but understanding the biological impact of its accumulation is limited to humans and common ecotoxicological model...
PFAS contamination of urban waters is widespread but understanding the biological impact of its accumulation is limited to humans and common ecotoxicological model organisms. Here, we combine PFAS exposure and bioaccumulation patterns with whole organism responses and omics-based ecosurveillance methods to investigate the potential impacts of PFAS on a top predator of wetlands, the tiger snake (Notechis scutatus). Tiger snakes (18 male and 17 female) were collected from four wetlands with varying PFAS chemical profiles and concentrations in Perth, Western Australia. Tiger snake livers were tested for 28 known PFAS compounds, and Σ28PFAS in liver tissues ranged between 322 ± 193 μg/kg at the most contaminated site to 1.31 ± 0.86 μg/kg at the least contaminated site. The dominant PFAS compound detected in liver tissues was PFOS. Lower body condition was associated with higher liver PFAS, and male snakes showed signs of high bioaccumulation whereas females showed signs of maternal offloading. Biochemical profiles of snake muscle, fat (adipose tissue), and gonads were analysed using a combination of liquid chromatography triple quadrupole (QqQ) and quadrupole time-of-flight (QToF) mass spectrometry methodologies. Elevated PFAS was associated with enriched energy production and maintenance pathways in the muscle, and had weak associations with energy-related lipids in the fat tissue, and lipids associated with cellular genesis and spermatogenesis in the gonads. These findings demonstrate the bioavailability of urban wetland PFAS in higher-order reptilian predators and suggest a negative impact on snake health and metabolic processes. This research expands on omics-based ecosurveillance tools for informing mechanistic toxicology and contributes to our understanding of the impact of PFAS residue on wildlife health to improve risk management and regulation.
Topics: Animals; Humans; Male; Female; Wetlands; Bioaccumulation; Elapidae; Lipids; Fluorocarbons
PubMed: 37400030
DOI: 10.1016/j.scitotenv.2023.165260 -
PeerJ 2023The spotted pond turtle () is a threatened and less explored species endemic to Bangladesh, India, Nepal, and Pakistan. To infer structural variation and matrilineal...
Matrilineal phylogeny and habitat suitability of the endangered spotted pond turtle (; Testudines: Geoemydidae): a two-dimensional approach to forecasting future conservation consequences.
The spotted pond turtle () is a threatened and less explored species endemic to Bangladesh, India, Nepal, and Pakistan. To infer structural variation and matrilineal phylogenetic interpretation, the present research decoded the mitogenome of (16,509 bp) using next-generation sequencing technology. The mitogenome comprises 13 protein-coding genes (PCGs), 22 transfer RNAs (tRNAs), two ribosomal RNAs (rRNAs), and one AT-rich control region (CR) with similar strand symmetry in vertebrates. The ATG was identified as a start codon in most of the PCGs except Cytochrome oxidase subunit 1 (cox1), which started with the GTG codon. The non-coding CR of was determined to have a unique structure and variation in different domains and stem-loop secondary structure as compared with other Batagurinae species. The PCGs-based Bayesian phylogeny inferred strong monophyletic support for all Batagurinae species and confirmed the sister relationship of with Pangshura and Batagur taxa. We recommend generating more mitogenomic data for other Batagurinae species to confirm their population structure and evolutionary relationships. In addition, the present study aims to infer the habitat suitability and habitat quality of in its global distribution, both in the present and future climatic scenarios. We identify that only 58,542 km (7.16%) of the total range extent (817,341 km) is suitable for this species, along with the fragmented habitats in both the eastern and western ranges. Comparative habitat quality assessment suggests the level of patch shape in the western range is higher (71.3%) compared to the eastern range. Our results suggest a massive decline of approximately 65.73% to 70.31% and 70.53% to 75.30% under ssp245 and ssp585 future scenarios, respectively, for the years between 2021-2040 and 2061-2080 compared with the current distribution. The present study indicates that proper conservation management requires greater attention to the causes and solutions to the fragmented distribution and safeguarding of this endangered species in the Indus, Ganges, and Brahmaputra (IGB) river basins.
Topics: Animals; Turtles; Phylogeny; Bayes Theorem; Reptiles; Biological Evolution; RNA, Ribosomal
PubMed: 37692114
DOI: 10.7717/peerj.15975 -
Biology Open Oct 2023Body coloration in ectotherms serves multiple biological functions, including avoiding predators, communicating with conspecific individuals, and involvement in...
Body coloration in ectotherms serves multiple biological functions, including avoiding predators, communicating with conspecific individuals, and involvement in thermoregulation. As ectotherms rely on environmental sources of heat to regulate their internal body temperature, stable melanistic body coloration or color change can be used to increase or decrease heat absorption and heat exchange with the environment. While melanistic coloration for thermoregulation functions to increase solar radiation absorption and consequently heating in many diurnal ectotherms, research on crepuscular and nocturnal ectotherms is lacking. Since crepuscular and nocturnal ectotherms generally absorb heat from the substrate, in these organisms melanistic coloration may have other primary functions beside thermoregulation. As such, in this work we hypothesized that the proportion of dorsal melanistic body coloration would not influence heating and cooling rates in the crepuscular gecko, Eublepharis macularius, and that changes in environmental temperature would not trigger color changes in this species. Temperature measurements of the geckos and of the environment were taken using infrared thermography and temperature loggers. Color data were obtained using objective photography and a newly developed custom software package. We found that body temperature reflected substrate temperatures, and that the proportion of melanistic coloration has no influence on heating or cooling rates or on color changes. These findings support that melanistic coloration in E. macularius may not be used for thermoregulation and strengthen the hypothesis that in animals active in low light conditions, melanistic coloration may be used instead for camouflage or other functions.
Topics: Animals; Body Temperature Regulation; Lizards; Body Temperature; Temperature; Hot Temperature
PubMed: 37756597
DOI: 10.1242/bio.060114 -
Journal of Thermal Biology Apr 2024
Topics: Lizards; Animals; Body Temperature Regulation; Wind
PubMed: 38648702
DOI: 10.1016/j.jtherbio.2024.103855 -
Scientific Reports Dec 2023Although turtles play a key role in maintaining healthy and balanced environments, these are endangered due to global trade to meet the high demand for food, medicine,...
Although turtles play a key role in maintaining healthy and balanced environments, these are endangered due to global trade to meet the high demand for food, medicine, and pets in Asia. In addition, imported non-native turtles have been controlled as alien invasive species in various countries, including Korea. Therefore, a rapid and accurate classification of imported turtles is needed to conserve and detect those in native ecosystems. In this study, eight Single Shot MultiBox Detector (SSD) models using different backbone networks were used to classify 36 imported turtles in Korea. The images of these species were collected from Google and were identified using morphological features. Then, these were divided into 70% for training, 15% for validation, and 15% for test sets. In addition, data augmentation was applied to the training set to prevent overfitting. Among the eight models, the Resnet18 model showed the highest mean Average Precision (mAP) at 88.1% and the fastest inference time at 0.024 s. The average correct classification rate of 36 turtles in this model was 82.8%. The results of this study could help in management of the turtle trade, specifically in improving detection of alien invasive species in the wild.
Topics: Animals; Ecosystem; Turtles; Deep Learning; Introduced Species; Republic of Korea
PubMed: 38066049
DOI: 10.1038/s41598-023-49022-3 -
International Journal of Molecular... Dec 2023The Chinese soft-shelled turtle , an economically important species in China, exhibits significant sexual dimorphism. Males are more valuable than females owing to their...
The Chinese soft-shelled turtle , an economically important species in China, exhibits significant sexual dimorphism. Males are more valuable than females owing to their wider calipash and faster growth. Estradiol (E2)-induced sex reversal is used to achieve all-male breeding of turtles; however, the mechanism of this sex reversal remains unclear. In this study, we characterized the gene, whose expression level was high in the gonads and brain and exhibited significant sexual dimorphism in the ovary. During embryonic development, was highly expressed at the initiation of ovarian differentiation. E2 and -RNAi treatment before sexual differentiation led to 1352, 908, 990, 1011, and 975 differentially expressed genes in five developmental stages, respectively, compared with only E2 treatment. The differentially expressed genes were clustered into 20 classes. The continuously downregulated and upregulated genes during gonadal differentiation were categorized into Class 0 ( = 271) and Class 19 ( = 606), respectively. KEGG enrichment analysis showed that significantly affected sexual differentiation via the Wnt, TGF-β, and TNF signaling pathways and mRNA surveillance pathway. The expression of genes involved in these signaling pathways, such as , , , and , changed significantly during gonadal differentiation. In conclusion, the deletion of may lead to significant upregulation of the mRNA surveillance pathway and TNF and Ras signaling pathways and downregulation of the Wnt and TGF-β signaling pathways, inhibiting E2-induced sex reversal. These findings suggest that may play a certain promoting effect during E2-induced sex reversal in .
Topics: Male; Female; Animals; Estradiol; Reptiles; Ovary; Transforming Growth Factor beta; RNA, Messenger
PubMed: 38203425
DOI: 10.3390/ijms25010248