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The diverse climatic and geological history of Southeast Asia has been a driving force behind significant Pleistocene and Holocene range dynamics and the consequent biological diversification in the region. Among the species exhibiting wide distributions, extending across several well-known zoogeographic barriers, the Elongated Tortoise (Indotestudo elongata) is noted for its extensive variability in size, shape, and colouration. To examine phylogeographic differentiation within I. elongata, we analysed three mitochondrial gene fragments (ND4, cyt b, and COI) for 52 individuals including fourteen historic specimens and 25 sequences obtained from Gen- Bank. Phylogenetic analyses of the concatenated alignment revealed genetic homogeneity across the range, supported by a shallow mean uncorrected p distance of 1.2% in cyt b. This corresponds to a surprising lack of biogeographic structuring. Concordantly, multivariate statistical analyses of morphometric and colouration-related characters of 166 adult tortoises (79 males and 87 females) from Myanmar, Thailand, Cambodia, and Vietnam showed no statistically significant differences between biogeographic units. The lack of any phylogeographic signal and morphological differentiation despite the presence of significant biogeographic barriers is unusual for a terrestrial vertebrate from this region. Archaeological evidence suggests that Elongated Tortoises have been used as a food item for millennia. It could be that their current wide distribution and the absence of genetic differentiation are the result of a significant range expansion caused by extensive human-mediated dispersal over the prehistoric and historic tortoise trade. The observed lack of phylogeographic structure considerably simplifies conservation measures such as conservation breeding, reintroduction, and population reinforcement. [ABSTRACT FROM AUTHOR]

The Asian box turtles of the Cuora galbinifrons complex (C. galbinifrons, C. bourreti, and C. picturata) rank among the most endangered chelonian species in the world. Despite several previous studies, the phylogenetic relationships and species boundaries of this complex remain a matter for dispute due to a shortage of field-collected samples for genetic validation, observed discordance between mitochondrial and nuclear markers, and reported intergradation zones combined with a strong tendency of hybridization in the genus. Here, we re-investigate the relationships and potential hybridization between the species of the C. galbinifrons complex based on the most comprehensive dataset to date consisting of 394 morphologically identified specimens (136 C. galbinifrons, 200 C. bourreti, 49 C. picturata, and nine individuals allegedly from Hainan). The turtles mainly came from assurance colonies as well as from zoological and private collections across the USA and Europe. Bayesian and Maximum Likelihood analyses of a concatenated mitochondrial dataset (COI and ND4 plus adjacent tRNA genes) yielded almost identical topologies, supporting three major clades corresponding to C. galbinifrons, C. bourreti, and C. picturata, respectively. In accordance with previous studies, C. bourreti represented the sister clade to C. galbinifrons and these two clades together were sister to C. picturata. Haplotype networks revealed pronounced mitochondrial divergences between the taxa. STRUCTURE and PCA analyses using 12 microsatellite loci also confirmed three distinct clusters that are in agreement with the recognized species. Only a few specimens with admixed ancestry (hybrids) or mismatched mitochondrial identity were revealed, suggesting extremely limited gene flow among the three species. However, this pattern could also reflect the separate captive management of the individual taxa and an underrepresentation of geographic contact zones in our sampling. [ABSTRACT FROM AUTHOR]

Asian freshwater turtles are severely threatened by overharvesting for local and international trade. Whilst some research exists on their occurrence in market places, basic studies on their natural history are scarce. Effective conservation action requires an understanding of both the threats to a species and its ecology. Our research aims to elucidate some basic aspects of the natural history of three freshwater turtle species: Notochelys platynota, Heosemys spinosa and Dogania subplana in Sabah, Malaysian Borneo. We collected opportunistic turtle data within two logging concessions from 2017 to 2019, and conducted dedicated turtle sampling via Visual Encounter Surveys (VES) along rivers in 2019. These data were used to determine population characteristics, habitat associations/separation, movements, recapture rates, breeding behaviour, and parasitism. We obtained 157, 40 and 13 records of N. platynota, D. subplana and H. spinosa, respectively. Roughly equal adult/juvenile ratios were detected in two species, whereas adults predominated (2.6:1) in N. platynota. Both N. platynota and H. spinosa exhibited similar sex ratios, with significant sexual dimorphism (males larger than females) in N. platynota. Notochelys platynota and D. subplana were significantly associated with wider streams compared to H. spinosa, whilst D. subplana were significantly associated with higher relative siltation than N. platynota. Recapture rates of N. platynota were low (N = 12), with recaptured N. platynota movements ranging from 10--489 meters. High rates of parasitism by freshwater leeches (Placobdelloides siamensis) were identified in N. platynota (41% of VES detections, N = 50), whilst 30% of H. spinosa were infested with ticks (N = 3). The effects of high parasitism on N. platynota require further study, however we observed a large breeding population of N. platynota in the logging reserves examined. Habitat separation between these three species at fine spatial scales, via stream width and siltation, likely permits their co-occurrence along the same stream networks. We recommend the protection of heterogeneous stream networks to improve effective conservation measures for these species. [ABSTRACT FROM AUTHOR]

Vertebrate's stress response plays a significant role in helping individuals adapt to changing environments. One of the most challenging stages in female turtles' life cycle is during oviposition, especially when the turtles' nest during the daytime and have to face massive nesting events (arribadas), limited space on the beach, and high temperatures. The Kemp's ridley sea turtle (Lepidochelys kempii) is the smallest sea turtle, which has to withstand high temperatures during the nesting process due to its diurnal habits. Our objective was to determine corticosterone concentration as a response to induced stress and estimate its variations at the beginning, middle, and end of the nesting season. We measured the corticosterone concentration in serial blood samples (0, 20, 40, and 60 min.) in 22 Kemp's ridley sea turtles during the beginning, the middle, and the end of the nesting season. Our results show that the turtles had a significant increase in corticosterone levels at 20 min. after the onset of stress, and we found that corticosterone decreased at the end of the nesting season. The results point to a rapid response of the hypothalamic--pituitary-adrenal axis. We suggest that glucocorticoid levels return to baseline at the end of the breeding season, and modulation may allow successful completion of nesting throughout the entire seasonal nesting period. [ABSTRACT FROM AUTHOR]

Temperature-dependent sex determination occurs in many species of turtles. Because substrates differ in their heat retention capacities, a relatively small change in ambient temperature can exert great influence on sex ratios of hatchlings from clutches deposited in different substrates even within the same geographical area. Since Podocnemis unifilis is one of the Amazonian turtle species (Podocnemididae) with high behavioural plasticity in the use of nesting sites, we tested the influence of soil types on hatchling sex ratios in the Piagaçu Purus Sustainable Development Reserve along the lower Purus River, Brazil. During the 2013 and 2014 nesting seasons, we evaluated 26 nests on a sand bank (n = 14) and clay banks (n = 12). Approximately half of the hatchlings that emerged from each nest were sexed via gonad histological analysis (n = 341). We found a higher incidence of females in nests from the sandy substrate and more males in nests from the clayey substrate (= 40.466, df = 1, P < 0.0001). Ratios of 1 male to 2.28 females were recorded from sand bank nests, and 1.9 males to 1 female from clay banks. Overall, however, the hatchling sex ratio approximated to 1:1. Due to the gradual increase in global temperatures, it has been suggested for species with Temperature Sex Determination (TSD) that some turtle populations become increasingly female-dominated. However, it is likely that the use of different nesting substrates may help to mitigate the effects of global warming on hatchling sex ratio, especially in species with greater behavioural plasticity, such as P. unifilis. [ABSTRACT FROM AUTHOR]

Nesting site selection is of great ecological and evolutionary importance for turtles, because it is a key determinant of individual reproductive success. In this study we evaluated the effects of two types of nesting substrate (sand bank and clay banks) on the incubation success of a generalist nesting species, Podocnemis unifilis, in a floodplain area in the Brazilian Amazon. Nesting characteristics were recorded during the nesting seasons of 2012-2014, when 634 nests were monitored throughout the incubation period. Mean size of laying females did not vary between substrate types (sand = 24.71 cm; clay = 25.44 cm; P = 0.2054), nor was clutch size related to females' sizes. However, females that nested on sand bank exhibited a clearer pattern of nest positioning relative to distances to vegetation and water line than those laying eggs on clay banks. Mean egg size (40.24 ± 2.68 mm) and weight (21.09 ± 5.46 g) did not vary between types of nesting substrate, and there was no variation in clutch size across the reproductive seasons for either substrate. On the other hand, clutch sizes were higher in nests in clay banks (28 ± 8) than those that were deposited in sand bank (22 ± 7). Mean incubation time was shorter in sand bank (62 ± 5.98) than in clay banks (77 ± 4.33). Although eclosion success for sand and clay nests was high (84.82 and 72.97%, respectively), incubation success was relatively low in both substrate types (sand = 57.34%; clay = 25.80%). On sand bank, clutch losses were mainly due to human predation (16%), on clay banks, human predation also affected 16% of the nests, but floods compromised another 30%. Natural predation was mostly due to ovivory by the lizard Tupinambis teguixin, although fire ants, Solenopsis geminata, also contributed to egg predation on clay banks. Hatchlings incubated on sand bank were on average larger and heavier than those from clay banks nests. Our results suggest that differences found in the life histories of different populations of P. unifilis reflect flexible responses that are largely linked to the diversity of habitats this species utilizes for nesting. Furthermore, the presence of source-sink and habitat patches should be considered for short term population management, beyond the creation of networks of reserves that incorporate and protect a variety of nesting sites that these small local groups depend on for their survival. [ABSTRACT FROM AUTHOR]

Use of space refers to the quantity and quality of habitat exploitation by animals in a certain locality. While quantity is the area of space used by the animal for its activities, quality refers to the locale and manner in which the animal selects its home range. Both parameters are of crucial importance in driving species distribution and abundance. Testudines are distributed across diverse regions, including areas under severe anthropogenic pressure, and many species are threatened, mainly due to habitat loss and overexploitation. We reviewed scientific literature published between 1995 and 2016 to assess taxonomic and geographic patterns in home ranges of freshwater and terrestrial chelonians based on biological and ecological characteristics and conservation status. We examined the trait "home range size", as well as its relationships with intrinsic and extrinsic factors (sex, diet, carapace size, habitat and study zone) and species-specific conservation status. Many of the reviewed studies focus on the Nearctic region, and Emydidae is the most commonly studied family. We found great variation in the home range sizes of species within the same family. Diet was identified as the main driver of home range size. Sex, carapace size, habitat and study zone were not significant as predictors of home range size. Conservation status does not seem to represent a factor driving the assessed studies since the number of investigations concerning threatened and non-threatened species was similar. Home range sizes of threatened species were significantly lower than those of non-threatened species. We recommend priority be applied on information gathering and defining conservation strategies for species in undersampled areas threatened by habitat loss. [ABSTRACT FROM AUTHOR]

Despite Mauritania's proximity to globally recognized sea turtle nesting hotspots, the Bijagos Archipelago in Guinea-Bissau and Boavista Island within the Cabo Verde Archipelago, data on the status of sea turtle species in Mauritania remain scant. To address this, we conducted an extensive 6-year field study with the aim of gathering data about sea turtle stranding events along the Mauritanian coast. Between 2009 and 2016, our team recorded 1787 stranded sea turtles in various stages of decomposition (fresh to advanced), including dry sea turtle carapaces in or near coastal villages. Individuals comprised green turtle (Chelonia mydas, 93%; N=1654), loggerhead turtle (Caretta caretta, 5%; N=90), leatherback turtle (Dermochelys coriacea, 2%; N=28), and olive Ridley turtle (Lepidochelys olivacea, 1%; N=15). Curved carapace length measurements taken from all recorded sea turtles indicated a dominant presence of immature individuals for C. mydas and C. caretta. Fishing lines, net entanglements, hooks, traces of knife cuts, and the remains of slaughtered individuals found in coastal villages indicated anthropogenic threats and poaching. Our results testify to the need to reinforce better fishing regulations and to combat poaching activities, which pose direct threats to sea turtles inhabiting/visiting the Mauritanian sea and beaches from other well-protected areas. The current status of sea turtles in Mauritania is of regional and global concern, because marine turtles are migratory species and the dangers they are exposed to in this area may directly impact on populations in the West Africa region. [ABSTRACT FROM AUTHOR]

We isolated and characterized 16 new di- and tetranucleotide microsatellite markers for the critically endangered Asian box turtle genus Cuora, focusing on the "Cuora trifasciata" species complex. The new markers were then used to analyse genetic variability and divergence amongst five described species within this complex, namely C. aurocapitata (n = 18), C. cyclornata (n = 31), C. pani (n = 6), C. trifasciata (n = 58), and C. zhoui (n = 7). Our results support the view that all five species represent valid taxa. Within two species (C. trifasciata and C. cyclornata), two distinct morphotypes were corroborated by microsatellite divergence. For three individuals, morphologically identified as being of hybrid origin, the hybrid status was confirmed by our genetic analysis. Our results confirm the controversial species (Cuora aurocapitata, C. cyclornata) and subspecies/morphotypes (C. cyclornata meieri, C. trifasciata cf. trifasciata) to be genetically distinct, which has critical implications for conservation strategies. [ABSTRACT FROM AUTHOR]

The article presents a study which examines the specimens of amphibians and reptiles in Araripe bioregion in Northeastern Brazil between 2004 and 2012. The study recognized three different geomorphological zones such as plateau zone, pediplain zone, and slope zone and collected specimens through active research, pitfall traps, and visual and auditory census. Result showed 31 anurans species, which include nine new records of amphibians including Dendropsophus minutus, Scinax gr. ruber, and physalaemus sp. Meanwhile, 78 reptile species are found that includes 14 new records. It mentions the first record of Mabuya frenata in the State of Ceará.