The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Steven E. Jasinski - One of the best experts on this subject based on the ideXlab platform.
-
a new slider turtle testudines emydidae deirochelyinae trachemys from the late hemphillian late miocene early pliocene of eastern tennessee and the evolution of the deirochelyines
PeerJ, 2018Co-Authors: Steven E. JasinskiAbstract:Trachemys (Testudines: Emydidae) represents one of the most well-known turtle genera today. The evolution of Trachemys, while being heavily documented with fossil representatives, is not well understood. Numerous fossils from the late Hemphillian Gray Fossil Site (GFS) in northeastern Tennessee help to elucidate its evolution. The fossil Trachemys at the GFS represent a new species. The new taxon, Trachemys haugrudi, is described, and currently represents the most thoroughly described fossil emydid species known. A phylogenetic analysis, including 31 species, focusing on the subfamily Deirochelyinae is performed that includes the new fossil species, along with numerous other modern and fossil deirochelyine species, representing the first phylogenetic analysis published that includes several fossil deirochelyines. The phylogenetic analysis, utilizing morphological evidence, provides monophyletic clades of all modern deirochelyines, including Chrysemys, Deirochelys, Pseudemys, Malaclemys, Graptemys, and Trachemys. A strict consensus tree finds the recently described fossil species Graptemys kerneri to be part of a clade of Graptemys + Malaclemys. Three fossil taxa, including one previously referred to Pseudemys (Pseudemys caelata) and two to Deirochelys (Deirochelys carri and Deirochelys floridana) are found to form a clade with modern Deirochelys reticularia reticularia, with D. floridana sister to the other members of the clade. Chrysemys is found to be part of a basal polytomy with Deirochelys in relation to other deirochelyine taxa. Two fossil taxa previously referred to Chrysemys (Chrysemys timida and Chrysemys williamsi) form a paraphyly with the modern Chrysemys picta picta and Deirochelys, and may be referable to distinct genera. Additionally, fossil taxa previously attributed to Trachemys (Trachemys hillii, Trachemys idahoensis, Trachemys inflata, and Trachemys platymarginata) and T. haugrudi are found to form a clade separate from clades of northern and southern Trachemys species, potentially suggesting a distinct lineage of Trachemys with no modern survivors. Hypotheses of phylogenetic relationships mostly agree between the present study and previous ones, although the inclusion of fossil taxa provides further clues to the evolution of parts of the Deirochelyinae. The inclusion of more fossil taxa and characters may help resolve the placement of some taxa, and further elucidate the evolution of these New World turtles.
-
A new slider turtle (Testudines: Emydidae: Deirochelyinae: Trachemys) from the late Hemphillian (late Miocene/early Pliocene) of eastern Tennessee and the evolution of the deirochelyines
PeerJ Inc., 2018Co-Authors: Steven E. JasinskiAbstract:Trachemys (Testudines: Emydidae) represents one of the most well-known turtle genera today. The evolution of Trachemys, while being heavily documented with fossil representatives, is not well understood. Numerous fossils from the late Hemphillian Gray Fossil Site (GFS) in northeastern Tennessee help to elucidate its evolution. The fossil Trachemys at the GFS represent a new species. The new taxon, Trachemys haugrudi, is described, and currently represents the most thoroughly described fossil emydid species known. A phylogenetic analysis, including 31 species, focusing on the subfamily Deirochelyinae is performed that includes the new fossil species, along with numerous other modern and fossil deirochelyine species, representing the first phylogenetic analysis published that includes several fossil deirochelyines. The phylogenetic analysis, utilizing morphological evidence, provides monophyletic clades of all modern deirochelyines, including Chrysemys, Deirochelys, Pseudemys, Malaclemys, Graptemys, and Trachemys. A strict consensus tree finds the recently described fossil species Graptemys kerneri to be part of a clade of Graptemys + Malaclemys. Three fossil taxa, including one previously referred to Pseudemys (Pseudemys caelata) and two to Deirochelys (Deirochelys carri and Deirochelys floridana) are found to form a clade with modern Deirochelys reticularia reticularia, with D. floridana sister to the other members of the clade. Chrysemys is found to be part of a basal polytomy with Deirochelys in relation to other deirochelyine taxa. Two fossil taxa previously referred to Chrysemys (Chrysemys timida and Chrysemys williamsi) form a paraphyly with the modern Chrysemys picta picta and Deirochelys, and may be referable to distinct genera. Additionally, fossil taxa previously attributed to Trachemys (Trachemys hillii, Trachemys idahoensis, Trachemys inflata, and Trachemys platymarginata) and T. haugrudi are found to form a clade separate from clades of northern and southern Trachemys species, potentially suggesting a distinct lineage of Trachemys with no modern survivors. Hypotheses of phylogenetic relationships mostly agree between the present study and previous ones, although the inclusion of fossil taxa provides further clues to the evolution of parts of the Deirochelyinae. The inclusion of more fossil taxa and characters may help resolve the placement of some taxa, and further elucidate the evolution of these New World turtles
J. Susanne Hauswaldt - One of the best experts on this subject based on the ideXlab platform.
-
Turtle soup, Prohibition, and the population genetic structure of Diamondback Terrapins (Malaclemys terrapin).
PloS one, 2017Co-Authors: Paul E. Converse, J. Susanne Hauswaldt, Shawn R. Kuchta, Willem M. RoosenburgAbstract:Diamondback terrapins (Malaclemys terrapin) were a popular food item in early twentieth century America, and were consumed in soup with sherry. Intense market demand for terrapin meat resulted in population declines, notably along the Atlantic seaboard. Efforts to supply terrapins to markets resulted in translocation events, as individuals were moved about to stock terrapin farms. However, in 1920 the market for turtle soup buckled with the enactment of the eighteenth amendment to the United States' Constitution-which initiated the prohibition of alcoholic drinks-and many terrapin fisheries dumped their stocks into local waters. We used microsatellite data to show that patterns of genetic diversity along the terrapin's coastal range are consistent with historical accounts of translocation and cultivation activities. We identified possible instances of human-mediated dispersal by estimating gene flow over historical and contemporary timescales, Bayesian model testing, and bottleneck tests. We recovered six genotypic clusters along the Gulf and Atlantic coasts with varying degrees of admixture, including increased contemporary gene flow from Texas to South Carolina, from North Carolina to Maryland, and from North Carolina to New York. In addition, Bayesian models incorporating translocation events outperformed stepping-stone models. Finally, we were unable to detect population bottlenecks, possibly due to translocation reintroducing genetic diversity into bottlenecked populations. Our data suggest that current patterns of genetic diversity in the terrapin were altered by the demand for turtle soup followed by the enactment of alcohol prohibition. In addition, our study shows that population genetic tools can elucidate metapopulation dynamics in taxa with complex genetic histories impacted by anthropogenic activities.
-
Population genetics of the diamondback terrapin (Malaclemys terrapin)
Molecular ecology, 2005Co-Authors: J. Susanne HauswaldtAbstract:We examined the population genetic structure of the diamondback terrapins ( Malaclemys terrapin ), within and among estuaries. Based on mark-recapture studies, these estuarine turtles have high site fidelity that is likely to make them vulnerable to local extinctions. We tested if observed site fidelity of adults would be reflected in intraestuarine population genetic structure of six highly polymorphic microsatellite loci (five tetranucleotide and one dinucleotide). No evidence was found for population structuring within the Charleston estuary nor among three different estuaries in South Carolina. We then examined four other terrapin populations from North Carolina to New York, as well as from the Florida Keys and from Texas. With increasing geographical distance, genetic differentiation increased from South Carolina through New York, but overall values were low. The dinucleotide locus contributed significantly more to the genetic differentiation of some population comparisons than any of the other loci. Interestingly, terrapins from South Carolina to New York were much more genetically similar to those from Texas ( ρ = 0.154) than to those from Florida ( ρ = 0.357). We attribute this pattern to extensive translocations of terrapins during the early 20th century to replenish diminished populations and to provide turtle farms with stocks. Terrapins collected in Texas were especially sought for shipment to the northeastern US because of their larger size. Our study indicates no population structure within or among adjacent estuaries. Thus, the mark-recapture information from adult and subadult feeding locations is a poor predictor of population genetic structure. Additionally, it appears that past human activities may have drastically altered the genetics of current populations. Finally, our data suggest that translocation of eggs or head starting of terrapins within estuaries or among adjacent estuaries is acceptable from a genetic standpoint.
-
Microsatellite DNA loci from the Diamondback terrapin (Malaclemys terrapin)
Molecular Ecology Notes, 2003Co-Authors: J. Susanne Hauswaldt, Travis C GlennAbstract:We describe polymerase chain recation (PCR) primers and conditions to amplify one dinucleotide and five tetranucleotide microsatellite DNA loci isolated from the Diamondback terrapin (Malaclemys terrapin). The PCR primers were tested on 21 terrapins from Cape Romain, SC, USA. The microsatellite primers developed yielded a high number of alleles (8–14) and high observed heterozygosities (0.57–1.0).
Tim L. King - One of the best experts on this subject based on the ideXlab platform.
-
Spatiotemporal analysis of gene flow in Chesapeake Bay Diamondback Terrapins (Malaclemys terrapin).
Molecular ecology, 2015Co-Authors: Paul E. Converse, Willem M. Roosenburg, Shawn R. Kuchta, Paula F. P. Henry, G. Michael Haramis, Tim L. KingAbstract:There is widespread concern regarding the impacts of anthropogenic activities on connectivity among populations of plants and animals, and understanding how contemporary and historical processes shape metapopulation dynamics is crucial for setting appropriate conservation targets. We used genetic data to identify population clusters and quantify gene flow over historical and contemporary time frames in the Diamondback Terrapin (Malaclemys terrapin). This species has a long and complicated history with humans, including commercial overharvesting and subsequent translocation events during the early twentieth century. Today, terrapins face threats from habitat loss and mortality in fisheries bycatch. To evaluate population structure and gene flow among Diamondback Terrapin populations in the Chesapeake Bay region, we sampled 617 individuals from 15 localities and screened individuals at 12 polymorphic microsatellite loci. Our goals were to demarcate metapopulation structure, quantify genetic diversity, estimate effective population sizes, and document temporal changes in gene flow. We found that terrapins in the Chesapeake Bay region harbour high levels of genetic diversity and form four populations. Effective population sizes were variable. Among most population comparisons, estimates of historical and contemporary terrapin gene flow were generally low (m ≈ 0.01). However, we detected a substantial increase in contemporary gene flow into Chesapeake Bay from populations outside the bay, as well as between two populations within Chesapeake Bay, possibly as a consequence of translocations during the early twentieth century. Our study shows that inferences across multiple time scales are needed to evaluate population connectivity, especially as recent changes may identify threats to population persistence.
-
Regional differentiation among populations of the Diamondback terrapin (Malaclemys terrapin)
Conservation Genetics, 2014Co-Authors: Kristen M. Hart, Margaret E. Hunter, Tim L. KingAbstract:The Diamondback terrapin (Malaclemys terrapin ) is a brackish-water turtle species whose populations have been fragmented due to anthropogenic activity such as development of coastal habitat and entrapment in commercial blue crab ( Callinectes sapidus ) fishing gear. Genetic analyses can improve conservation efforts for the long-term protection of the species. We used microsatellite DNA analysis to investigate levels of gene flow among and genetic variability within 21 geographically separate collections of the species distributed from Massachusetts to Texas. Quantified levels of genetic variability (allelic diversity, genotypic frequencies, and heterozygosity) revealed three zones of genetic discontinuity, resulting in four discrete populations: Northeast Atlantic, Coastal Mid-Atlantic, Florida and Texas/Louisiana. The average number of alleles and expected heterozygosity for the four genetic clusters were N_A = 6.54 and H_E = 0.050, respectively. However, the geographic boundaries of the populations did not correspond to accepted terrapin subspecies limits. Our results illuminate not only the need to sample terrapins in additional sites, specifically in the southeast, but also the necessity for allowing uninterrupted gene flow among population groupings to preserve current levels of genetic diversity.
Willem M. Roosenburg - One of the best experts on this subject based on the ideXlab platform.
-
Turtle soup, Prohibition, and the population genetic structure of Diamondback Terrapins (Malaclemys terrapin).
PloS one, 2017Co-Authors: Paul E. Converse, J. Susanne Hauswaldt, Shawn R. Kuchta, Willem M. RoosenburgAbstract:Diamondback terrapins (Malaclemys terrapin) were a popular food item in early twentieth century America, and were consumed in soup with sherry. Intense market demand for terrapin meat resulted in population declines, notably along the Atlantic seaboard. Efforts to supply terrapins to markets resulted in translocation events, as individuals were moved about to stock terrapin farms. However, in 1920 the market for turtle soup buckled with the enactment of the eighteenth amendment to the United States' Constitution-which initiated the prohibition of alcoholic drinks-and many terrapin fisheries dumped their stocks into local waters. We used microsatellite data to show that patterns of genetic diversity along the terrapin's coastal range are consistent with historical accounts of translocation and cultivation activities. We identified possible instances of human-mediated dispersal by estimating gene flow over historical and contemporary timescales, Bayesian model testing, and bottleneck tests. We recovered six genotypic clusters along the Gulf and Atlantic coasts with varying degrees of admixture, including increased contemporary gene flow from Texas to South Carolina, from North Carolina to Maryland, and from North Carolina to New York. In addition, Bayesian models incorporating translocation events outperformed stepping-stone models. Finally, we were unable to detect population bottlenecks, possibly due to translocation reintroducing genetic diversity into bottlenecked populations. Our data suggest that current patterns of genetic diversity in the terrapin were altered by the demand for turtle soup followed by the enactment of alcohol prohibition. In addition, our study shows that population genetic tools can elucidate metapopulation dynamics in taxa with complex genetic histories impacted by anthropogenic activities.
-
Spatiotemporal analysis of gene flow in Chesapeake Bay Diamondback Terrapins (Malaclemys terrapin).
Molecular ecology, 2015Co-Authors: Paul E. Converse, Willem M. Roosenburg, Shawn R. Kuchta, Paula F. P. Henry, G. Michael Haramis, Tim L. KingAbstract:There is widespread concern regarding the impacts of anthropogenic activities on connectivity among populations of plants and animals, and understanding how contemporary and historical processes shape metapopulation dynamics is crucial for setting appropriate conservation targets. We used genetic data to identify population clusters and quantify gene flow over historical and contemporary time frames in the Diamondback Terrapin (Malaclemys terrapin). This species has a long and complicated history with humans, including commercial overharvesting and subsequent translocation events during the early twentieth century. Today, terrapins face threats from habitat loss and mortality in fisheries bycatch. To evaluate population structure and gene flow among Diamondback Terrapin populations in the Chesapeake Bay region, we sampled 617 individuals from 15 localities and screened individuals at 12 polymorphic microsatellite loci. Our goals were to demarcate metapopulation structure, quantify genetic diversity, estimate effective population sizes, and document temporal changes in gene flow. We found that terrapins in the Chesapeake Bay region harbour high levels of genetic diversity and form four populations. Effective population sizes were variable. Among most population comparisons, estimates of historical and contemporary terrapin gene flow were generally low (m ≈ 0.01). However, we detected a substantial increase in contemporary gene flow into Chesapeake Bay from populations outside the bay, as well as between two populations within Chesapeake Bay, possibly as a consequence of translocations during the early twentieth century. Our study shows that inferences across multiple time scales are needed to evaluate population connectivity, especially as recent changes may identify threats to population persistence.
-
Geographic variation in egg size and lipid provisioning in the diamondback terrapin Malaclemys terrapin.
Physiological and biochemical zoology : PBZ, 2012Co-Authors: Phil E. Allman, Allen R. Place, Willem M. RoosenburgAbstract:AbstractUnderstanding phenotypic differentiation among populations of wide-ranging species remains at the core of life-history research, because adaptation to local environmental conditions is expected. For example, when energy resources influence offspring fitness (as in oviparous ectotherms), the egg and hatchling environments are expected to influence selection by acting on the amount of energy allocated to offspring. Here we identify population variation in egg mass, length, width, and volume from diamondback terrapin Malaclemys terrapin eggs collected in Rhode Island (RI), Maryland (MD), and South Carolina (SC). Egg size (mean volume: 7.6, 8.1, and 9.1 cc in RI, MD, and SC, respectively) and clutch size (mean no. eggs: 16.1, 12.2, and 6.0 in RI, MD, and SC, respectively) differed among populations, which indicated that females produce larger clutches with smaller eggs at high latitudes and smaller clutches of larger eggs at lower latitudes. Lipid analyses indicated that eggs from SC contained yolks w...
-
impacts of multiple stressors on growth and metabolic rate of Malaclemys terrapin
Environmental Toxicology and Chemistry, 2009Co-Authors: Dawn K Holliday, Adria A Elskus, Willem M. RoosenburgAbstract:Coastal species encounter numerous physiological stressors ranging from daily fluctuations in salinity and temperature to anthropogenic contaminants, yet the effects of such stressor combinations on aquatic organisms remain largely unknown. Exposure to environmental contaminants, such as polychlorinated biphenyls (PCBs), can disrupt physiological processes, and while physi- ological responses to salinity change are well understood, the combined effects of salinity change and contaminants on these processes are unknown. Marine and brackish water turtles are often simultaneously exposed to both stressors. We exposed male, eight-month-old diamondback terrapins to one of four salinity treatments (0, 10, 20, and 30 parts per thousand) in the presence and absence of the anthropogenic stressor 3,3,4,4,5-pentachlorobiphenyl (PCB 126, 20 g/g via intraperitoneal injection) and monitored growth (carapace length and mass) and metabolic rate for six months. Exposure to PCB 126 significantly reduced growth (p 0.0001), lowered standard metabolic rates (SMRs; p 0.0001), and altered respiratory pattern (p 0.0001). Salinity stress reduced growth (p 0.0001) and altered the respiratory pattern (p 0.0001) but had no overall effect on metabolic rate (p 0.33). No interactive effects of PCBs and salinity were seen on either growth or metabolic rate. Our data indicate terrapins may be able to cope with some effects of salinity change through physiological adjustments but are less able to cope with PCBs. We show that PCB 126 disrupts the ecophysiological mechanisms that affect life history traits and thus ultimately could alter population structure and dynamics. The present study enriches our understanding of the environmental toxicology of reptiles and aids in the interpretation of health conditions documented in field-collected turtles contaminated with PCBs. Keywords—Turtles Pentachlorobiphenyl 126 Salinity Metabolic rate and growth Hematocrit
-
Egg Component Comparisons within and among Clutches of the Diamondback Terrapin, Malaclemys terrapin
Copeia, 2005Co-Authors: Willem M. Roosenburg, Teresa DennisAbstract:The relationship between egg size and composition (relative amounts of lipid, protein, and water) can play an important role in determining neonate size, quality, or the amount of post-hatching care observed in many reptiles. We evaluated the relationship among egg wet mass, non-polar lipid mass, water content, shell dry mass, and lean dry mass within and among seven clutches of the Diamondback Terrapin, Malaclemys terrapin, from Chesapeake Bay. Egg size varied considerably among clutches, but was relatively uniform within clutches. Non-polar lipid mass, lean dry mass, and water content correlated positively with egg wet mass indicating that larger eggs contain a proportionally greater amount of these components. There was no relationship between egg wet mass and shell dry mass. Clutches had similar, positive slopes but different intercepts in the relationships between lean dry mass and lipid mass and between water content and total dry mass. Thus, clutches differed in the relative proportions of resources but had similar allocation patterns of egg components. Our data cannot resolve whether these effects are due to differences in resource availability or differences in the physiological mechanisms involved in egg provisioning.
Harold W Avery - One of the best experts on this subject based on the ideXlab platform.
-
Between the bay and a hard place: Altered diamondback terrapin nesting movements demonstrate the effects of coastal barriers upon estuarine wildlife
The Journal of Wildlife Management, 2015Co-Authors: Julianne M. Winters, Edward A. Standora, Harold W Avery, James R SpotilaAbstract:Human development can impede wildlife moving between complementary habitats, particularly in highly disturbed coastal ecosystems. Coastal barriers may affect the behavior of diamondback terrapins (Malaclemys terrapin), a salt-tolerant estuarine turtle that requires access to complementary upland habitat for annual nesting. We used telemetry to quantify terrestrial and aquatic movements of 78 nesting female terrapins in response to coastal barriers at 2 sites in Barnegat Bay, New Jersey, a heavily developed estuary. Nesting female terrapins traveled significantly greater distances with more tortuous paths or spent significantly more time in the water when their movements were obstructed than females nesting at beaches with no obstructions. We hypothesize that the additional effort and displacement associated with reproduction where obstructions exist will reduce terrapin fitness and potentially contribute to population declines. Our study demonstrates a unique approach to quantifying effects of barriers on organisms requiring complementary habitats, and improves our understanding of the impacts of shoreline hardening on estuarine wildlife threatened by encroaching coastal development. © 2015 The Wildlife Society.
-
Behavioral responses of diamondback terrapins (Malaclemys terrapin terrapin) to recreational boat sounds.
Advances in experimental medicine and biology, 2012Co-Authors: Lori A. Lester, Walter F Bien, Edward A. Standora, Harold W AveryAbstract:Anthropogenic sound caused by recreational boat traffic is a major concern for many marine animals because it may alter their behavior, mask sounds necessary for survival, and cause hearing loss. These alterations could potentially lower the chance of survival for individuals and lead to population declines. In this study, the diamondback terrapin (Malaclemys terrapin terrapin) in Barnegat Bay, NJ, is used as a model organism to understand how boat engine sound influences behavior. Previously, we used the auditory brain stem response (ABR) technique to determine that terrapins can hear a limited range of low-frequency tones less than 1,000 Hz. Most anthropogenic activities such as recreational boating also produce sound with low-frequency components (Richardson and Wursig 1997).
-
sex biased dispersal and natal philopatry in the diamondback terrapin Malaclemys terrapin
Molecular Ecology, 2010Co-Authors: Claire M Sheridan, James R Spotila, Walter F Bien, Harold W AveryAbstract:Nesting ecology and population studies indicate that diamondback terrapins (Malaclemys terrapin) exhibit nest site fidelity and high habitat fidelity. However, genetic studies indicate high levels of gene flow. Because dispersal affects the genetics and population dynamics of a species, we used six highly polymorphic microsatellite markers to investigate sex-biased dispersal and natal philopatry of M. terrapin in Barnegat Bay, NJ. We compared results of spatial autocorrelation analysis, assignment methods and Wright’s FST estimators to a mark–recapture analysis. Mark–recapture analysis over a 4year period indicated that most individuals have relatively small home ranges (<2 km), with mature females displaying greater home ranges than males. Goodness of fit analysis of our mark–recapture study indicated that some juvenile males were likely transient individuals moving through our study location. Mean assignment indices and firstgeneration migrant tests indicated that mature males were more prone to disperse than mature females, but first-generation migrant tests indicated that per capita there are more female than male dispersers. Thus, the relative importance of males and females on gene flow in terrapin populations may change in relation to population sex ratios. Spatial autocorrelation analysis indicated that mature females exhibited natal philopatry to nesting beaches, but first-generation migrant tests indicated that a small number of females failed to nest on natal beaches. Finally, we discuss the important conservation implications of male-biased dispersal and natal philopatry in the diamondback terrapin.
-
Recreational boats and turtles: behavioral mismatches result in high rates of injury.
Public Library of Science (PLoS), 2024Co-Authors: Lori A. Lester, Harold W Avery, Andrew S. Harrison, Edward A. StandoraAbstract:Recreational boats are a dominant feature of estuarine waters in the United States. Boat strike injury and mortality may have a detrimental effect on populations of diamondback terrapins (Malaclemys terrapin), a keystone species in estuarine ecosystems. In Barnegat Bay, New Jersey, 11% of terrapins (n = 2,644) have scars consistent with injuries from boats. Conservative estimates of injury rates from boats increased from 2006 to 2011. When exposed to playback recordings of approaching boat engines of varying sizes and speeds in situ, terrapins did not significantly change their behavior in response to sounds of boat engines of different sizes. The lack of behavioral response of terrapins to boat sounds helps explain high rates of injury and mortality of terrapins and may threaten the viability of terrapin populations. Boater education courses that discuss impacts of boats to wildlife, combined with closure of areas of high terrapin densities to boating, are necessary to protect terrapins and other aquatic species from injury and mortality caused by motorized boats
