S. Behera, B. Tripathy, B. C. Choudhury, K. Sivakumar
Abstract The migratory movements of 14 olive ridley turtles (Lepidochelys olivacea) in the Bay of Bengal were studied using satellite telemetry during 2009–2010. Tracking data show that olive ridley turtles undertake open-ocean migrations in the bay and exhibit migratory corridor between foraging habitat of Sri Lanka and nesting sites along the Odisha coast of India. Tracking durations ranged 7–331 d (mean = 151 ± 95.9 d). The tracked turtles had a mean traveling speed of 2.49 ± 0.02 km/hr and moved an average of 31.7 km/d, remaining within a mean distance of 163.28 ± 50.9 km (range, 1–535 km) from the east coast of India. Turtles occupied waters with sea surface temperature (SST) ranging from 24°C to 31°C with chlorophyll concentrations of 0 to 3.9 mg/m3. Our study confirms that olive ridley turtles in the Bay of Bengal move within a broad range of SSTs and chlorophyll a concentrations; no correlation was found between turtle movements and these 2 oceanographic parameters (r2 = 0.02, n = 77). Our data indicate that many habitats within the Bay of Bengal are important for olive ridley turtles and that the entire bay should be considered a priority conservation region for this vulnerable species.
{"title":"Movements of Olive Ridley Turtles (Lepidochelys olivacea) in the Bay of Bengal, India, Determined via Satellite Telemetry","authors":"S. Behera, B. Tripathy, B. C. Choudhury, K. Sivakumar","doi":"10.2744/CCB-1245.1","DOIUrl":"https://doi.org/10.2744/CCB-1245.1","url":null,"abstract":"Abstract The migratory movements of 14 olive ridley turtles (Lepidochelys olivacea) in the Bay of Bengal were studied using satellite telemetry during 2009–2010. Tracking data show that olive ridley turtles undertake open-ocean migrations in the bay and exhibit migratory corridor between foraging habitat of Sri Lanka and nesting sites along the Odisha coast of India. Tracking durations ranged 7–331 d (mean = 151 ± 95.9 d). The tracked turtles had a mean traveling speed of 2.49 ± 0.02 km/hr and moved an average of 31.7 km/d, remaining within a mean distance of 163.28 ± 50.9 km (range, 1–535 km) from the east coast of India. Turtles occupied waters with sea surface temperature (SST) ranging from 24°C to 31°C with chlorophyll concentrations of 0 to 3.9 mg/m3. Our study confirms that olive ridley turtles in the Bay of Bengal move within a broad range of SSTs and chlorophyll a concentrations; no correlation was found between turtle movements and these 2 oceanographic parameters (r2 = 0.02, n = 77). Our data indicate that many habitats within the Bay of Bengal are important for olive ridley turtles and that the entire bay should be considered a priority conservation region for this vulnerable species.","PeriodicalId":50703,"journal":{"name":"Chelonian Conservation and Biology","volume":"17 1","pages":"44 - 53"},"PeriodicalIF":0.7,"publicationDate":"2018-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2744/CCB-1245.1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42797136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Salleh, H. Nishizawa, T. Ishihara, S. A. Sah, A. Chowdhury
Abstract The microhabitats of green turtle (Chelonia mydas) nests were investigated to identify key factors influencing nesting success by monitoring both successful nests (n = 43) and aborted nests (n = 106) created by the same individuals (n = 9) from September 2013 to September 2014 on Penang Island, Malaysia. The effect of sand particle size on nesting success was significant, suggesting that green turtles tend to abort nesting at sites with sands of particle sizes < 1 mm. In addition, nests were successful at superficial sand temperatures less than 32.95°C.
{"title":"Importance of Sand Particle Size and Temperature for Nesting Success of Green Turtles in Penang Island, Malaysia","authors":"S. Salleh, H. Nishizawa, T. Ishihara, S. A. Sah, A. Chowdhury","doi":"10.2744/CCB-1266.1","DOIUrl":"https://doi.org/10.2744/CCB-1266.1","url":null,"abstract":"Abstract The microhabitats of green turtle (Chelonia mydas) nests were investigated to identify key factors influencing nesting success by monitoring both successful nests (n = 43) and aborted nests (n = 106) created by the same individuals (n = 9) from September 2013 to September 2014 on Penang Island, Malaysia. The effect of sand particle size on nesting success was significant, suggesting that green turtles tend to abort nesting at sites with sands of particle sizes < 1 mm. In addition, nests were successful at superficial sand temperatures less than 32.95°C.","PeriodicalId":50703,"journal":{"name":"Chelonian Conservation and Biology","volume":"17 1","pages":"116 - 122"},"PeriodicalIF":0.7,"publicationDate":"2018-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2744/CCB-1266.1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42826298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The yellow-spotted river turtle (Podocnemis unifilis) plays ecological roles in the Amazonian aquatic ecosystem and has cultural and economic significance for indigenous peoples. Because spatial ecology and movement data are nonexistent for this species, we radio tracked 63 individuals in the Napo River between August 2015 and February 2017. Mean linear range size was 16.2 km (n = 31) and mean home range size was 5.2 km2 (n = 27). Our results are the first range size estimates for P. unifilis and suggest that the species could be treated as a short-distance facultative migrant with local seasonal movements.
{"title":"Space Use of Yellow-Spotted River Turtles (Podocnemis unifilis) in Yasuni National Park, Ecuador","authors":"A. Naveda-Rodríguez, R. Cueva, G. Zapata-Ríos","doi":"10.2744/CCB-1270.1","DOIUrl":"https://doi.org/10.2744/CCB-1270.1","url":null,"abstract":"Abstract The yellow-spotted river turtle (Podocnemis unifilis) plays ecological roles in the Amazonian aquatic ecosystem and has cultural and economic significance for indigenous peoples. Because spatial ecology and movement data are nonexistent for this species, we radio tracked 63 individuals in the Napo River between August 2015 and February 2017. Mean linear range size was 16.2 km (n = 31) and mean home range size was 5.2 km2 (n = 27). Our results are the first range size estimates for P. unifilis and suggest that the species could be treated as a short-distance facultative migrant with local seasonal movements.","PeriodicalId":50703,"journal":{"name":"Chelonian Conservation and Biology","volume":"17 1","pages":"37 - 43"},"PeriodicalIF":0.7,"publicationDate":"2018-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2744/CCB-1270.1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45678570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M.N.S. Viana, Jessica dos Anjos Oliveira, M. Agostini, J. Erickson, Giovanne Matias de Morais, L. A. S. Monjeló, P. C. M. Andrade, Daniely Félix-Silva, Waldesse Piragé de Oliveira Júnior, J. Sites, R. Vogt, T. Hrbek, I. Farias
Abstract Podocnemis sextuberculata (Pleurodira: Podocnemididae) is widely distributed throughout the Amazon drainage basin in Brazil, Colombia, and Peru. Telemetry and previous molecular data suggest that P. sextuberculata lacks population structure in the central Amazon basin of Brazil. Generalization of these results, however, requires much-broader sampling across a range of habitats of this broadly distributed species. For this reason, we tested the hypothesis of panmixia in P. sextuberculata, analyzing a total of 319 specimens sequenced for the mitochondrial control region. Our sampling included localities from 16 areas in the Amazon basin from rivers characteristic of the Amazon basin (whitewater), clearwater rivers of the Guiana shield (Branco, Trombetas, and Nhamundá rivers), and the Brazilian shield (Xingu River). The hypothesis of panmixia was rejected because the results of analysis of molecular variance, pairwise ФST, and Bayesian analysis of population structure indicated population structure in the group of individuals from the locality of Xingu which was not correlated to a pattern of isolation by distance. We suggest that the populations of P. sextuberculata of the Brazilian Amazon basin are composed of 2 management units, one represented by populations restricted to the Xingu River and the other represented by all other populations. The population of the Xingu should be viewed with attention and concern, especially considering the direct and indirect impacts of damming the Xingu River.
{"title":"Population Genetic Structure of the Threatened Amazon River Turtle, Podocnemis sextuberculata (Testudines, Podocnemididae)","authors":"M.N.S. Viana, Jessica dos Anjos Oliveira, M. Agostini, J. Erickson, Giovanne Matias de Morais, L. A. S. Monjeló, P. C. M. Andrade, Daniely Félix-Silva, Waldesse Piragé de Oliveira Júnior, J. Sites, R. Vogt, T. Hrbek, I. Farias","doi":"10.2744/CCB-1262.1","DOIUrl":"https://doi.org/10.2744/CCB-1262.1","url":null,"abstract":"Abstract Podocnemis sextuberculata (Pleurodira: Podocnemididae) is widely distributed throughout the Amazon drainage basin in Brazil, Colombia, and Peru. Telemetry and previous molecular data suggest that P. sextuberculata lacks population structure in the central Amazon basin of Brazil. Generalization of these results, however, requires much-broader sampling across a range of habitats of this broadly distributed species. For this reason, we tested the hypothesis of panmixia in P. sextuberculata, analyzing a total of 319 specimens sequenced for the mitochondrial control region. Our sampling included localities from 16 areas in the Amazon basin from rivers characteristic of the Amazon basin (whitewater), clearwater rivers of the Guiana shield (Branco, Trombetas, and Nhamundá rivers), and the Brazilian shield (Xingu River). The hypothesis of panmixia was rejected because the results of analysis of molecular variance, pairwise ФST, and Bayesian analysis of population structure indicated population structure in the group of individuals from the locality of Xingu which was not correlated to a pattern of isolation by distance. We suggest that the populations of P. sextuberculata of the Brazilian Amazon basin are composed of 2 management units, one represented by populations restricted to the Xingu River and the other represented by all other populations. The population of the Xingu should be viewed with attention and concern, especially considering the direct and indirect impacts of damming the Xingu River.","PeriodicalId":50703,"journal":{"name":"Chelonian Conservation and Biology","volume":"16 1","pages":"128 - 138"},"PeriodicalIF":0.7,"publicationDate":"2017-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2744/CCB-1262.1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46879494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Descriptions of the developmental stages of embryonic marine turtles are presented in the form of a dichotomous key supported by drawings to facilitate identifying stages of development in the field. The key emphasizes the sequential appearance or loss of external morphological structures that can be seen either with the unaided eye or with a ×10 hand lens and a handheld light. Stages are placed in the context of normal beach temperatures to facilitate estimation of laying date, emergence date, and events that cause embryonic mortality. Measurements of embryos are presented to assist determining stage.
{"title":"A Field Key to the Developmental Stages of Marine Turtles (Cheloniidae) with Notes on the Development of Dermochelys","authors":"Jeffrey D. Miller, J. Mortimer, C. Limpus","doi":"10.2744/CCB-1261.1","DOIUrl":"https://doi.org/10.2744/CCB-1261.1","url":null,"abstract":"Abstract Descriptions of the developmental stages of embryonic marine turtles are presented in the form of a dichotomous key supported by drawings to facilitate identifying stages of development in the field. The key emphasizes the sequential appearance or loss of external morphological structures that can be seen either with the unaided eye or with a ×10 hand lens and a handheld light. Stages are placed in the context of normal beach temperatures to facilitate estimation of laying date, emergence date, and events that cause embryonic mortality. Measurements of embryos are presented to assist determining stage.","PeriodicalId":50703,"journal":{"name":"Chelonian Conservation and Biology","volume":"16 1","pages":"111 - 122"},"PeriodicalIF":0.7,"publicationDate":"2017-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2744/CCB-1261.1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41686419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Many marine organisms (invertebrates, fishes) produce large numbers of small offspring (larvae) that differ in appearance and behavior from adults. That outcome occurs because larvae as they grow occupy one or more ontogenetic niches that select for phenotypes that differ from those that promote adult survival. Our purpose in this study was to determine whether similar associations also occur in marine turtles. To find out, we examined relationships between juvenile appearance (body shape) and the ontogenetic niches occupied by 3 species of marine turtles: leatherbacks (Dermochelys coriacea) and 2 cheloniids (green turtles, Chelonia mydas; loggerheads, Caretta caretta). Our measurements indicate that juvenile body shape differs the least from adult body shape in leatherbacks and the most from adults in the 2 cheloniid species. We present evidence from other studies showing that juvenile leatherbacks occupy ontogenetic niches that resemble adult niches, whereas during their ontogeny, both juvenile green turtles and loggerheads make radical niche shifts as they transition between oceanic and neritic habitats. These results are thus consistent with the hypothesis that many morphological and behavioral characteristics expressed by juvenile marine turtles, like those of other larval forms, are best understood as evolved responses shaped by the characteristics of their ontogenetic niches.
{"title":"Ontogenetic Niches and the Development of Body Shape in Juvenile Sea Turtles","authors":"Jessica H. Pate, M. Salmon","doi":"10.2744/CCB-1274.1","DOIUrl":"https://doi.org/10.2744/CCB-1274.1","url":null,"abstract":"Abstract Many marine organisms (invertebrates, fishes) produce large numbers of small offspring (larvae) that differ in appearance and behavior from adults. That outcome occurs because larvae as they grow occupy one or more ontogenetic niches that select for phenotypes that differ from those that promote adult survival. Our purpose in this study was to determine whether similar associations also occur in marine turtles. To find out, we examined relationships between juvenile appearance (body shape) and the ontogenetic niches occupied by 3 species of marine turtles: leatherbacks (Dermochelys coriacea) and 2 cheloniids (green turtles, Chelonia mydas; loggerheads, Caretta caretta). Our measurements indicate that juvenile body shape differs the least from adult body shape in leatherbacks and the most from adults in the 2 cheloniid species. We present evidence from other studies showing that juvenile leatherbacks occupy ontogenetic niches that resemble adult niches, whereas during their ontogeny, both juvenile green turtles and loggerheads make radical niche shifts as they transition between oceanic and neritic habitats. These results are thus consistent with the hypothesis that many morphological and behavioral characteristics expressed by juvenile marine turtles, like those of other larval forms, are best understood as evolved responses shaped by the characteristics of their ontogenetic niches.","PeriodicalId":50703,"journal":{"name":"Chelonian Conservation and Biology","volume":"16 1","pages":"185 - 193"},"PeriodicalIF":0.7,"publicationDate":"2017-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2744/CCB-1274.1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49655948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Effective management of long-lived species requires demographic and life-history data that are best acquired from long-term studies. The ringed sawback (Graptemys oculifera), endemic to the Pearl River watershed of Mississippi and Louisiana, is a species of management concern at both the state and federal levels. Population sizes, trapping success, basking counts, sex ratios, survivorship, and growth of this species were investigated at 5 sites on the Pearl River in Mississippi over a 25-yr period. Estimates of age at maturity were 4.6 yrs for males and 9.1 yrs for females. Mean annual survivorship estimates for males, females, and juveniles were 0.88, 0.93, and 0.69, respectively. Maximum longevity estimates were 48.8 yrs for males and 76.4 yrs for females. Average longevity estimates were 8.5 yrs for males and 13.9 yrs for females. The sex ratio of captured turtles was male-biased before 2000 but unbiased after 2000. Realized population growth estimates indicated that 4 populations were stable over the 25-yr period and 1 population had declined. Population estimates and basking counts trended downward through time at most sites. Trapping success after 2000 for all sites combined declined by 77%, 45%, and 25% for juveniles, males, and females, respectively. Taken together, these data indicate that 1 population of G. oculifera has declined, 3 appear to be in the initial stages of decline, and 1 is relatively stable. Additional monitoring of these populations will be necessary to determine if these trends continue into the future.
{"title":"Long-Term Trends in Ringed Sawback (Graptemys oculifera) Growth, Survivorship, Sex Ratios, and Population Sizes in the Pearl River, Mississippi","authors":"Robert L. Jones","doi":"10.2744/CCB-1268.1","DOIUrl":"https://doi.org/10.2744/CCB-1268.1","url":null,"abstract":"Abstract Effective management of long-lived species requires demographic and life-history data that are best acquired from long-term studies. The ringed sawback (Graptemys oculifera), endemic to the Pearl River watershed of Mississippi and Louisiana, is a species of management concern at both the state and federal levels. Population sizes, trapping success, basking counts, sex ratios, survivorship, and growth of this species were investigated at 5 sites on the Pearl River in Mississippi over a 25-yr period. Estimates of age at maturity were 4.6 yrs for males and 9.1 yrs for females. Mean annual survivorship estimates for males, females, and juveniles were 0.88, 0.93, and 0.69, respectively. Maximum longevity estimates were 48.8 yrs for males and 76.4 yrs for females. Average longevity estimates were 8.5 yrs for males and 13.9 yrs for females. The sex ratio of captured turtles was male-biased before 2000 but unbiased after 2000. Realized population growth estimates indicated that 4 populations were stable over the 25-yr period and 1 population had declined. Population estimates and basking counts trended downward through time at most sites. Trapping success after 2000 for all sites combined declined by 77%, 45%, and 25% for juveniles, males, and females, respectively. Taken together, these data indicate that 1 population of G. oculifera has declined, 3 appear to be in the initial stages of decline, and 1 is relatively stable. Additional monitoring of these populations will be necessary to determine if these trends continue into the future.","PeriodicalId":50703,"journal":{"name":"Chelonian Conservation and Biology","volume":"16 1","pages":"215 - 228"},"PeriodicalIF":0.7,"publicationDate":"2017-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2744/CCB-1268.1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48593082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Sirsi, Shailendra Singh, A. Tripathi, Shawn F. McCracken, M. Forstner, B. Horne
Abstract Characterizing variation in reproductive output is foundational to understanding the demography of a population and determining management strategies. Doing so is paramount when the species of interest is threatened with extinction. The red-crowned roofed turtle (Batagur kachuga) and the three-striped roofed turtle (Batagur dhongoka) are severely threatened by overharvesting and habitat loss. Despite their imperiled status, there are very few published studies on species ecology and life history to enable effective conservation; the 3 published studies that are available were completed nearly 3 decades ago. We herein provide information on variation in reproductive output for these turtles in the Chambal River of North India. Generalized linear models and analyses of variance were fitted to data on nesting density, fecundity, and egg volume. The number of nests showed an overall decline across 3 seasons (2007, 2008, and 2010) over a 4-yr duration with the highest number of nests observed in the middle of each nesting season. Peak nesting activity potentially occurs at lowest river depth or maximum availability of nesting habitat. The observed decline in the number of nests could be related to a decline in the nesting cohort or a geographic shift in suitable nesting habitat or changes in food resource availability and/or acquisition, leading to fewer females nesting. The number of nests in B. kachuga were significantly negatively correlated with total precipitation in the immediately preceding year. Presumably, total precipitation may affect the amount of nesting habitat available or availability of some other limiting resource. Reproductive output in both species varied as a function of fecundity rather than egg volume, implying that maturity occurs at larger body sizes for egg volume to be unconstrained, which would require relatively long generation times. Variation in clutch size could be tied to variable resource acquisition patterns, although total precipitation was not found to be an appropriate proxy. Potential variation in fecundity as a function of body size was not accounted for in the study. The study corroborated previous findings that B. kachuga lays larger and fewer eggs than B. dhongoka. These results contribute to understanding the life history of these poorly documented turtle species and toward informing conservation actions. Future studies over a larger spatial extent need to characterize nesting sites and nest-site fidelity and incorporate data from individual females.
{"title":"Variation in Reproductive Output of the Red-crowned Roofed Turtle (Batagur kachuga) and the Three-striped Roofed Turtle (Batagur dhongoka) in the Chambal River of North India","authors":"S. Sirsi, Shailendra Singh, A. Tripathi, Shawn F. McCracken, M. Forstner, B. Horne","doi":"10.2744/CCB-1236.1","DOIUrl":"https://doi.org/10.2744/CCB-1236.1","url":null,"abstract":"Abstract Characterizing variation in reproductive output is foundational to understanding the demography of a population and determining management strategies. Doing so is paramount when the species of interest is threatened with extinction. The red-crowned roofed turtle (Batagur kachuga) and the three-striped roofed turtle (Batagur dhongoka) are severely threatened by overharvesting and habitat loss. Despite their imperiled status, there are very few published studies on species ecology and life history to enable effective conservation; the 3 published studies that are available were completed nearly 3 decades ago. We herein provide information on variation in reproductive output for these turtles in the Chambal River of North India. Generalized linear models and analyses of variance were fitted to data on nesting density, fecundity, and egg volume. The number of nests showed an overall decline across 3 seasons (2007, 2008, and 2010) over a 4-yr duration with the highest number of nests observed in the middle of each nesting season. Peak nesting activity potentially occurs at lowest river depth or maximum availability of nesting habitat. The observed decline in the number of nests could be related to a decline in the nesting cohort or a geographic shift in suitable nesting habitat or changes in food resource availability and/or acquisition, leading to fewer females nesting. The number of nests in B. kachuga were significantly negatively correlated with total precipitation in the immediately preceding year. Presumably, total precipitation may affect the amount of nesting habitat available or availability of some other limiting resource. Reproductive output in both species varied as a function of fecundity rather than egg volume, implying that maturity occurs at larger body sizes for egg volume to be unconstrained, which would require relatively long generation times. Variation in clutch size could be tied to variable resource acquisition patterns, although total precipitation was not found to be an appropriate proxy. Potential variation in fecundity as a function of body size was not accounted for in the study. The study corroborated previous findings that B. kachuga lays larger and fewer eggs than B. dhongoka. These results contribute to understanding the life history of these poorly documented turtle species and toward informing conservation actions. Future studies over a larger spatial extent need to characterize nesting sites and nest-site fidelity and incorporate data from individual females.","PeriodicalId":50703,"journal":{"name":"Chelonian Conservation and Biology","volume":"16 1","pages":"203 - 214"},"PeriodicalIF":0.7,"publicationDate":"2017-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2744/CCB-1236.1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41409482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Viviana Hernández-Montoya, Vivian P. Páez, Claudia P Ceballos
Abstract Understanding reproductive biology and embryonic development is vital to guide conservation programs for endangered species. The Red-footed Tortoise, Chelonoidis carbonarius, is a vulnerable species for which the sex determination mechanism and the transitional temperatures range are unknown. In an attempt to obtain this information, we incubated 145 eggs (38 nests) at 3 constant temperatures: 29°C, 31°C, and 33°C. All embryos incubated at 33°C (n = 49) died during the first third of the incubation period. Of the eggs incubated at 31°C (n = 47), only 10.6% hatched, and 2.12% of the embryos showed malformations of the carapace, head, or legs. Of the eggs incubated at 29°C (n = 49), 52% hatched successfully with 10.2% exhibiting body malformations. From the 30 neonates obtained, we were able to sex 20 individuals by laparoscopies, 2 by gonads histology, 1 was impossible to identify because of the small sizes of the gonads at the time of death, and the remaining were released back to their tortoise origin of collection without being sexed. These results suggest that C. carbonarius exhibits a temperature-dependent sex determination mechanism with females produced at, or above, 29°C. Our incidental findings of embryo malformations, asynchronous hatching, and incomplete yolk absorption suggest that this species may be able to arrest embryonic development via embryonic diapause, aestivation, or both. Future studies should focus on the developmental biology of this species including confirmation of the production of males at temperatures below 29°C.
{"title":"Effects of Temperature on Sex Determination and Embryonic Development in the Red-footed Tortoise, Chelonoidis carbonarius","authors":"Viviana Hernández-Montoya, Vivian P. Páez, Claudia P Ceballos","doi":"10.2744/CCB-1267.1","DOIUrl":"https://doi.org/10.2744/CCB-1267.1","url":null,"abstract":"Abstract Understanding reproductive biology and embryonic development is vital to guide conservation programs for endangered species. The Red-footed Tortoise, Chelonoidis carbonarius, is a vulnerable species for which the sex determination mechanism and the transitional temperatures range are unknown. In an attempt to obtain this information, we incubated 145 eggs (38 nests) at 3 constant temperatures: 29°C, 31°C, and 33°C. All embryos incubated at 33°C (n = 49) died during the first third of the incubation period. Of the eggs incubated at 31°C (n = 47), only 10.6% hatched, and 2.12% of the embryos showed malformations of the carapace, head, or legs. Of the eggs incubated at 29°C (n = 49), 52% hatched successfully with 10.2% exhibiting body malformations. From the 30 neonates obtained, we were able to sex 20 individuals by laparoscopies, 2 by gonads histology, 1 was impossible to identify because of the small sizes of the gonads at the time of death, and the remaining were released back to their tortoise origin of collection without being sexed. These results suggest that C. carbonarius exhibits a temperature-dependent sex determination mechanism with females produced at, or above, 29°C. Our incidental findings of embryo malformations, asynchronous hatching, and incomplete yolk absorption suggest that this species may be able to arrest embryonic development via embryonic diapause, aestivation, or both. Future studies should focus on the developmental biology of this species including confirmation of the production of males at temperatures below 29°C.","PeriodicalId":50703,"journal":{"name":"Chelonian Conservation and Biology","volume":"16 1","pages":"164 - 171"},"PeriodicalIF":0.7,"publicationDate":"2017-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2744/CCB-1267.1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47189109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Recently, 2 studies almost simultaneously described the same previously unrecognized species of semiaquatic Southeast Asian snail-eating turtle (Testudines: Geoemydidae: Malayemys Lindholm 1931): Malayemys khoratensis Ihlow et al. 2016 and M. isan Sumontha et al. 2016. In order to determine the valid name for the species in question, we performed a comprehensive bibliographical analysis of both underlying publications. We come to the conclusion that M. khoratensis is the older available name that fulfills all requirements of being published for the purpose of nomenclature. The name was made available in full agreement with the requirements of the International Code of Zoological Nomenclature in an electronic publication of the journal PLoS ONE on 6 April 2016. The earliest date a printed copy of Volume 8(1) of the journal Taprobanica (which contains the description of M. isan and constitutes the nomenclaturally relevant edition of this publication outlet) can be shown to have been in existence, via actual printing records, is 13 April 2016. However, 13 April, in fact, dates after we placed a request to purchase a printed copy and after we asked several questions about the journal's publication procedures. By definition, our finding unveils Taprobanica 8(1) as being published under a print-on-demand model, a violation of Article 8.1 in that such print-on-demand publications do not constitute a published work under the Code. In agreement with Article 9.12, Volume 8(1) of Taprobanica cannot be considered published for the purpose of nomenclature and thus, following Article 11.1, M. isan cannot be considered an available name in zoological nomenclature. The valid name for the recently described species of Malayemys consequently is M. khoratensis: the Khorat snail-eating turtle.
{"title":"On the Nomenclatural Status of the Recently Described Snail-eating Turtle from Southeast Asia (Testudines, Geoemydidae): Malayemys khoratensis Ihlow et al. 2016 vs. Malayemys isan Sumontha et al. 2016","authors":"S. Thomson, M. Lambertz","doi":"10.2744/CCB-1260.1","DOIUrl":"https://doi.org/10.2744/CCB-1260.1","url":null,"abstract":"Abstract Recently, 2 studies almost simultaneously described the same previously unrecognized species of semiaquatic Southeast Asian snail-eating turtle (Testudines: Geoemydidae: Malayemys Lindholm 1931): Malayemys khoratensis Ihlow et al. 2016 and M. isan Sumontha et al. 2016. In order to determine the valid name for the species in question, we performed a comprehensive bibliographical analysis of both underlying publications. We come to the conclusion that M. khoratensis is the older available name that fulfills all requirements of being published for the purpose of nomenclature. The name was made available in full agreement with the requirements of the International Code of Zoological Nomenclature in an electronic publication of the journal PLoS ONE on 6 April 2016. The earliest date a printed copy of Volume 8(1) of the journal Taprobanica (which contains the description of M. isan and constitutes the nomenclaturally relevant edition of this publication outlet) can be shown to have been in existence, via actual printing records, is 13 April 2016. However, 13 April, in fact, dates after we placed a request to purchase a printed copy and after we asked several questions about the journal's publication procedures. By definition, our finding unveils Taprobanica 8(1) as being published under a print-on-demand model, a violation of Article 8.1 in that such print-on-demand publications do not constitute a published work under the Code. In agreement with Article 9.12, Volume 8(1) of Taprobanica cannot be considered published for the purpose of nomenclature and thus, following Article 11.1, M. isan cannot be considered an available name in zoological nomenclature. The valid name for the recently described species of Malayemys consequently is M. khoratensis: the Khorat snail-eating turtle.","PeriodicalId":50703,"journal":{"name":"Chelonian Conservation and Biology","volume":"16 1","pages":"239 - 245"},"PeriodicalIF":0.7,"publicationDate":"2017-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2744/CCB-1260.1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42973480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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