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Steven G. Platt - One of the best experts on this subject based on the ideXlab platform.
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A recent population assessment of the American crocodile (Crocodylus acutus) in Turneffe Atoll, Belize
2015Co-Authors: Steven G. Platt, Thomas R Rainwater, Stephen NicholsAbstract:ABSTRACT — We investigated the status of the American crocodile (Crocodylus acutus) in Turneffe Atoll, Belize during 2002 and 2004. A combination of spotlight surveys and counts of recently hatched nests were used to census the crocodile population. A total of 49 crocodiles were observed along 40.1 km of survey route (1.2 crocodiles/km) during spotlight surveys in 2002. This encounter rate was not significantly different from that reported in surveys conducted during the mid-1990's. Eight and 20 recently hatched nests were found in 2002 and 2004, respectively. The number of nests found in 2004 exceeds the previously reported maximum count of 15, suggesting that recruitment of breeding females into the population may be occurring. Crocodile nests were found at four sites in Tumefied Atoll. The most significant nesting beach in Belize is located on Northern Cay and currently threatened by a proposed tourist development. Failure to protect this beach could have potentially devastating consequences for C. acutus in Belize. HE American crocodile (Crocodylus acutus) has one of the most extensive distributions of any crocodilian in the New World, occurring along the Atlantic and Pacific Coasts of Mexico, and Central and South America as well as th
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Diet of the American Crocodile (Crocodylus acutus) in Marine Environments of Coastal Belize
Journal of Herpetology, 2013Co-Authors: Steven G. Platt, John B. Thorbjarnarson, Thomas R Rainwater, David MartinAbstract:Abstract We studied diet and size-related dietary patterns among American Crocodiles (Crocodylus acutus) in marine habitats of coastal Belize (1996–1997). Prey items recovered from crocodile (N = 97) stomach contents included insects, mollusks, crustaceans, fish, amphibians, reptiles, birds, and mammals. Based on an overlapping group analysis of percent occurrence, we concluded that hatchlings and small juveniles feed largely on insects and crustaceans, larger juveniles broaden their diet to include fish and nonfish vertebrates, subadults consume increasing amounts of crustaceans with lesser amounts of insects and nonfish vertebrates, and adults subsist primarily on marine crustaceans. Dietary diversity was uniformly low across all size classes but greatest among small and large juveniles. Conversely, hatchlings, subadults, and adults had the most specialized (least diverse) diet owing to reliance upon a limited selection of prey, largely insects (hatchlings) or crustaceans (subadults and adults). Dietary...
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Size estimation, morphometrics, sex ratio, sexual size dimorphism, and biomass of Crocodylus acutus in the coastal zone of Belize
2011Co-Authors: Steven G. Platt, John B. Thorbjarnarson, Thomas R Rainwater, David MartinAbstract:We used morphometric data from 151 Crocodylus acutus captured in the Coastal Zone of Belize to develop predic - tive models for deducing body size (total length (TL) and snout-vent length (SVL)) from measurements of single attributes (dorsal cranial length (DCL), cranial width (CW), snout length (SL) and width (SW), body mass (BM), and rear foot length (RFL)), quantify sexual size dimorphism, examine ontogenetic changes in cranial morphology, and estimate standing crop biomass of crocodiles on an offshore atoll. Strong positive allometric relationships were found between measurements of body length and other morphometric attributes, and provide a reliable means to estimate body length from tracks, skulls, and body parts. The maximum DCL:CW ratio of 2.4 was attained at a body size that coincided with a dietary shift from in - vertebrates to larger vertebrate prey. The SL:SW ratio of C. acutus partially overlapped that of C. moreletii, and consequently this attribute was not useful for distinguishing these two morphologically similar, sympatric species. The mean DCL:TL ratio was 0.15 and remained constant across body sizes ranging from hatchlings to large adults. Both overall and adult sex ratio (female:male) were not significantly different from parity. The mean SVL of males (111.3 ± 20.7 cm) was significantly greater than that of females (101.0 ± 6.2 cm). A compressed sexual size dimorphism index (SDI) of 2.10 was calculated for C. acutus in coastal Belize. Crocodylus acutus in coastal Belize appear to attain a smaller body size than reported for other populations. Standing crop biomass of C. acutus in the Turneffe Atoll was estimated to be 0.92 kg/ha.
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ocular disease in american crocodiles Crocodylus acutus in costa rica
Journal of Wildlife Diseases, 2011Co-Authors: Thomas R Rainwater, Steven G. Platt, Nicholas J Millichamp, Luz Denia Barrantes Barrantes, Brady Barr, Juan Rafael Bolanos Montero, Mike T Abel, George P. Cobb, Todd A AndersonAbstract:Beginning in early 2006, an ocular disease of unknown etiology was routinely observed in American crocodiles (Crocodylus acutus) inhabiting the highly polluted Tarcoles River in west-central Costa Rica. We examined the nature and incidence of ocular disease in Tarcoles crocodiles and assessed the possible association between the disease and accumulation of chemical pollutants in diseased individuals. During 12–15 September and 12–13 December 2007, crocodiles were captured and examined for ocular disease and sampled to determine environmental contaminant accumulation. Three of 11 (27.3%) crocodiles captured (all males) exhibited unilateral ocular disease, primarily characterized by corneal opacity and scarring, anterior synechia, and phthisis bulbi. Multiple pollutants were detected in crocodile caudal scutes (organochlorine pesticides [OCPs] and metals), crocodile blood (OCPs), and sediments (OCPs and metals) from the Tarcoles, but no associations were found between contaminant accumulation and the incide...
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Scalation of the American Crocodile, Crocodylus acutus (Crocodylidae, Crocodilia), from the Coastal Zone of Northern Belize
Caribbean Journal of Science, 2010Co-Authors: Steven G. Platt, John B. Thorbjarnarson, Thomas R RainwaterAbstract:Abstract. We here describe scalation in a large sample (n = 80) of American crocodiles, Crocodylus acutus, collected from the coastal zone of northern Belize. Differences between our data and the few published descriptions of C. acutus were found among post-occipital, nuchal, dorsal, ventral, and double-crested caudal scale groups, suggesting that interpopulational differences in scalation may exist in this widely distributed species. Whether populations can be identified on the basis of scalation remains to be determined.
John B. Thorbjarnarson - One of the best experts on this subject based on the ideXlab platform.
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Diet of the American Crocodile (Crocodylus acutus) in Marine Environments of Coastal Belize
Journal of Herpetology, 2013Co-Authors: Steven G. Platt, John B. Thorbjarnarson, Thomas R Rainwater, David MartinAbstract:Abstract We studied diet and size-related dietary patterns among American Crocodiles (Crocodylus acutus) in marine habitats of coastal Belize (1996–1997). Prey items recovered from crocodile (N = 97) stomach contents included insects, mollusks, crustaceans, fish, amphibians, reptiles, birds, and mammals. Based on an overlapping group analysis of percent occurrence, we concluded that hatchlings and small juveniles feed largely on insects and crustaceans, larger juveniles broaden their diet to include fish and nonfish vertebrates, subadults consume increasing amounts of crustaceans with lesser amounts of insects and nonfish vertebrates, and adults subsist primarily on marine crustaceans. Dietary diversity was uniformly low across all size classes but greatest among small and large juveniles. Conversely, hatchlings, subadults, and adults had the most specialized (least diverse) diet owing to reliance upon a limited selection of prey, largely insects (hatchlings) or crustaceans (subadults and adults). Dietary...
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Size estimation, morphometrics, sex ratio, sexual size dimorphism, and biomass of Crocodylus acutus in the coastal zone of Belize
2011Co-Authors: Steven G. Platt, John B. Thorbjarnarson, Thomas R Rainwater, David MartinAbstract:We used morphometric data from 151 Crocodylus acutus captured in the Coastal Zone of Belize to develop predic - tive models for deducing body size (total length (TL) and snout-vent length (SVL)) from measurements of single attributes (dorsal cranial length (DCL), cranial width (CW), snout length (SL) and width (SW), body mass (BM), and rear foot length (RFL)), quantify sexual size dimorphism, examine ontogenetic changes in cranial morphology, and estimate standing crop biomass of crocodiles on an offshore atoll. Strong positive allometric relationships were found between measurements of body length and other morphometric attributes, and provide a reliable means to estimate body length from tracks, skulls, and body parts. The maximum DCL:CW ratio of 2.4 was attained at a body size that coincided with a dietary shift from in - vertebrates to larger vertebrate prey. The SL:SW ratio of C. acutus partially overlapped that of C. moreletii, and consequently this attribute was not useful for distinguishing these two morphologically similar, sympatric species. The mean DCL:TL ratio was 0.15 and remained constant across body sizes ranging from hatchlings to large adults. Both overall and adult sex ratio (female:male) were not significantly different from parity. The mean SVL of males (111.3 ± 20.7 cm) was significantly greater than that of females (101.0 ± 6.2 cm). A compressed sexual size dimorphism index (SDI) of 2.10 was calculated for C. acutus in coastal Belize. Crocodylus acutus in coastal Belize appear to attain a smaller body size than reported for other populations. Standing crop biomass of C. acutus in the Turneffe Atoll was estimated to be 0.92 kg/ha.
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evolutionary history of cuban crocodiles Crocodylus rhombifer and Crocodylus acutus inferred from multilocus markers
Journal of Experimental Zoology, 2011Co-Authors: Yoamel Miliangarcia, Miryam Venegasanaya, Roberto Friassoler, Andrew J Crawford, Roberto Ramostargarona, Roberto Rodriguezsoberon, Manuel Alonsotabet, John B. ThorbjarnarsonAbstract:Among crocodilians, Crocodylus rhombifer is one of the world’s most endangered species with the smallest natural distribution. In Cuba, this endemic species coexists with the American crocodile (Crocodylus acutus). Hybridization between these two species is well known in captivity and might occur in the wild, but has never been demonstrated genetically. Here, we combined molecular data with environmental, geographic, and fossil data to infer the evolutionary history of Crocodylus in the Cuban Archipelago, and to evaluate genealogical support for species boundaries. We analyzed seven microsatellite loci plus DNA sequence data from nuclear (RAG-1) and mitochondrial (cytochrome b and cytochrome oxidase I) genes from 89 wild-caught individuals in Cuba, Grand Cayman Island, Jamaica, and Central America, and two samples from zoo collections. Microsatellites showed evidence of introgression, suggesting potential hybridization among Cuban groups. In Cuba, C. acutus contained one mitochondrial DNA (mtDNA) haplotype, whereas C. rhombifer contained two haplotypes. MtDNA data showed that C. acutus is paraphyletic with respect to C. rhombifer, revealing 1% sequence divergence between species within Cuba vs. 8% divergence between Cuban forms and mainland C. acutus. We suggest that hybridization has been a historical as well as a current phenomenon between C. acutus and C. rhombifer. These findings suggest that long-term conservation of crocodiles in Cuba will require identification of genetically pure and hybrid individuals, and a decrease in anthropogenic activities. We also recommend more extensive morphological and genetic analyses of Cuban population to establish clear boundaries of the hybrid zone betweenC. acutus and C. rhombifer. J. Exp. Zool. 315:358‐375, 2011. & 2011 Wiley-Liss, Inc.
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Evolutionary history of Cuban crocodiles Crocodylus rhombifer and Crocodylus acutus inferred from multilocus markers
Journal of experimental zoology. Part A Ecological genetics and physiology, 2011Co-Authors: Yoamel Milián-garcía, Andrew J Crawford, John B. Thorbjarnarson, Miryam Venegas-anaya, Oris I. Sanjur, Roberto Frias‐soler, Roberto Ramos‐targarona, Roberto Rodríguez‐soberón, Manuel Alonso-tabet, Georgina Espinosa-lópezAbstract:Among crocodilians, Crocodylus rhombifer is one of the world's most endangered species with the smallest natural distribution. In Cuba, this endemic species coexists with the American crocodile (Crocodylus acutus). Hybridization between these two species is well known in captivity and might occur in the wild, but has never been demonstrated genetically. Here, we combined molecular data with environmental, geographic, and fossil data to infer the evolutionary history of Crocodylus in the Cuban Archipelago, and to evaluate genealogical support for species boundaries. We analyzed seven microsatellite loci plus DNA sequence data from nuclear (RAG-1) and mitochondrial (cytochrome b and cytochrome oxidase I) genes from 89 wild-caught individuals in Cuba, Grand Cayman Island, Jamaica, and Central America, and two samples from zoo collections. Microsatellites showed evidence of introgression, suggesting potential hybridization among Cuban groups. In Cuba, C. acutus contained one mitochondrial DNA (mtDNA) haplotype, whereas C. rhombifer contained two haplotypes. MtDNA data showed that C. acutus is paraphyletic with respect to C. rhombifer, revealing 1% sequence divergence between species within Cuba vs. 8% divergence between Cuban forms and mainland C. acutus. We suggest that hybridization has been a historical as well as a current phenomenon between C. acutus and C. rhombifer. These findings suggest that long-term conservation of crocodiles in Cuba will require identification of genetically pure and hybrid individuals, and a decrease in anthropogenic activities. We also recommend more extensive morphological and genetic analyses of Cuban population to establish clear boundaries of the hybrid zone between C. acutus and C. rhombifer.
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tropical cyclones and reproductive ecology of Crocodylus acutus cuvier 1807 reptilia crocodilia crocodylidae on a caribbean atoll in mexico
Journal of Natural History, 2010Co-Authors: Pierre Charruau, John B. Thorbjarnarson, Yann HénautAbstract:Crocodylus acutus, a coastal species nesting in sand beaches, could be affected by increasing tropical cyclone frequency. We studied key characteristics of C. acutus reproductive ecology on Banco Chinchorro atoll from 2006 to 2009, including the impact of two tropical cyclones. Hurricanes increased canopy openness causing earlier nesting the following year. Crocodiles nested at the beginning of the wet season with hatching in mid-wet season; this could represent a compromise between risking nest flooding and increasing freshwater availability for hatchlings. Tropical cyclones dramatically reduced nesting success by cooling and flooding clutches. Nursery sites were usually hypersaline, but heavy rainfall from tropical cyclones can likely benefit hatchling survival by decreasing salinity. While tropical cyclones have negative short-term impacts on crocodile nesting, they likely have an overall beneficial effect by creating and maintaining open sandy nesting areas used by C. acutus and they may explain its w...
Thomas R Rainwater - One of the best experts on this subject based on the ideXlab platform.
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A recent population assessment of the American crocodile (Crocodylus acutus) in Turneffe Atoll, Belize
2015Co-Authors: Steven G. Platt, Thomas R Rainwater, Stephen NicholsAbstract:ABSTRACT — We investigated the status of the American crocodile (Crocodylus acutus) in Turneffe Atoll, Belize during 2002 and 2004. A combination of spotlight surveys and counts of recently hatched nests were used to census the crocodile population. A total of 49 crocodiles were observed along 40.1 km of survey route (1.2 crocodiles/km) during spotlight surveys in 2002. This encounter rate was not significantly different from that reported in surveys conducted during the mid-1990's. Eight and 20 recently hatched nests were found in 2002 and 2004, respectively. The number of nests found in 2004 exceeds the previously reported maximum count of 15, suggesting that recruitment of breeding females into the population may be occurring. Crocodile nests were found at four sites in Tumefied Atoll. The most significant nesting beach in Belize is located on Northern Cay and currently threatened by a proposed tourist development. Failure to protect this beach could have potentially devastating consequences for C. acutus in Belize. HE American crocodile (Crocodylus acutus) has one of the most extensive distributions of any crocodilian in the New World, occurring along the Atlantic and Pacific Coasts of Mexico, and Central and South America as well as th
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Diet of the American Crocodile (Crocodylus acutus) in Marine Environments of Coastal Belize
Journal of Herpetology, 2013Co-Authors: Steven G. Platt, John B. Thorbjarnarson, Thomas R Rainwater, David MartinAbstract:Abstract We studied diet and size-related dietary patterns among American Crocodiles (Crocodylus acutus) in marine habitats of coastal Belize (1996–1997). Prey items recovered from crocodile (N = 97) stomach contents included insects, mollusks, crustaceans, fish, amphibians, reptiles, birds, and mammals. Based on an overlapping group analysis of percent occurrence, we concluded that hatchlings and small juveniles feed largely on insects and crustaceans, larger juveniles broaden their diet to include fish and nonfish vertebrates, subadults consume increasing amounts of crustaceans with lesser amounts of insects and nonfish vertebrates, and adults subsist primarily on marine crustaceans. Dietary diversity was uniformly low across all size classes but greatest among small and large juveniles. Conversely, hatchlings, subadults, and adults had the most specialized (least diverse) diet owing to reliance upon a limited selection of prey, largely insects (hatchlings) or crustaceans (subadults and adults). Dietary...
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Size estimation, morphometrics, sex ratio, sexual size dimorphism, and biomass of Crocodylus acutus in the coastal zone of Belize
2011Co-Authors: Steven G. Platt, John B. Thorbjarnarson, Thomas R Rainwater, David MartinAbstract:We used morphometric data from 151 Crocodylus acutus captured in the Coastal Zone of Belize to develop predic - tive models for deducing body size (total length (TL) and snout-vent length (SVL)) from measurements of single attributes (dorsal cranial length (DCL), cranial width (CW), snout length (SL) and width (SW), body mass (BM), and rear foot length (RFL)), quantify sexual size dimorphism, examine ontogenetic changes in cranial morphology, and estimate standing crop biomass of crocodiles on an offshore atoll. Strong positive allometric relationships were found between measurements of body length and other morphometric attributes, and provide a reliable means to estimate body length from tracks, skulls, and body parts. The maximum DCL:CW ratio of 2.4 was attained at a body size that coincided with a dietary shift from in - vertebrates to larger vertebrate prey. The SL:SW ratio of C. acutus partially overlapped that of C. moreletii, and consequently this attribute was not useful for distinguishing these two morphologically similar, sympatric species. The mean DCL:TL ratio was 0.15 and remained constant across body sizes ranging from hatchlings to large adults. Both overall and adult sex ratio (female:male) were not significantly different from parity. The mean SVL of males (111.3 ± 20.7 cm) was significantly greater than that of females (101.0 ± 6.2 cm). A compressed sexual size dimorphism index (SDI) of 2.10 was calculated for C. acutus in coastal Belize. Crocodylus acutus in coastal Belize appear to attain a smaller body size than reported for other populations. Standing crop biomass of C. acutus in the Turneffe Atoll was estimated to be 0.92 kg/ha.
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ocular disease in american crocodiles Crocodylus acutus in costa rica
Journal of Wildlife Diseases, 2011Co-Authors: Thomas R Rainwater, Steven G. Platt, Nicholas J Millichamp, Luz Denia Barrantes Barrantes, Brady Barr, Juan Rafael Bolanos Montero, Mike T Abel, George P. Cobb, Todd A AndersonAbstract:Beginning in early 2006, an ocular disease of unknown etiology was routinely observed in American crocodiles (Crocodylus acutus) inhabiting the highly polluted Tarcoles River in west-central Costa Rica. We examined the nature and incidence of ocular disease in Tarcoles crocodiles and assessed the possible association between the disease and accumulation of chemical pollutants in diseased individuals. During 12–15 September and 12–13 December 2007, crocodiles were captured and examined for ocular disease and sampled to determine environmental contaminant accumulation. Three of 11 (27.3%) crocodiles captured (all males) exhibited unilateral ocular disease, primarily characterized by corneal opacity and scarring, anterior synechia, and phthisis bulbi. Multiple pollutants were detected in crocodile caudal scutes (organochlorine pesticides [OCPs] and metals), crocodile blood (OCPs), and sediments (OCPs and metals) from the Tarcoles, but no associations were found between contaminant accumulation and the incide...
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Scalation of the American Crocodile, Crocodylus acutus (Crocodylidae, Crocodilia), from the Coastal Zone of Northern Belize
Caribbean Journal of Science, 2010Co-Authors: Steven G. Platt, John B. Thorbjarnarson, Thomas R RainwaterAbstract:Abstract. We here describe scalation in a large sample (n = 80) of American crocodiles, Crocodylus acutus, collected from the coastal zone of northern Belize. Differences between our data and the few published descriptions of C. acutus were found among post-occipital, nuchal, dorsal, ventral, and double-crested caudal scale groups, suggesting that interpopulational differences in scalation may exist in this widely distributed species. Whether populations can be identified on the basis of scalation remains to be determined.
Frank J. Mazzotti - One of the best experts on this subject based on the ideXlab platform.
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high levels of population genetic differentiation in the american crocodile Crocodylus acutus
PLOS ONE, 2020Co-Authors: Frank J. Mazzotti, Kurt Mclaren, Natalia A Rossi, Angelica Menchacarodriguez, Rafael Antelo, Byron S Wilson, Rafael Crespo, Joe WasilewskiAbstract:The American crocodile (Crocodylus acutus) is a widely distributed species across coastal and brackish areas of the Neotropical region of the Americas and the Greater Antilles. Available information on patterns of genetic differentiation in C. acutus shows a complex structuring influenced by interspecific interactions (mainly hybridization) and anthropogenic actions (mostly historical hunting, recent poaching, habitat loss and fragmentation, and unintentional translocation of individuals). In this study, we used data on mitochondrial DNA control region and 11 nuclear polymorphic microsatellite loci to assess the degree of population structure of C. acutus in South America, North America, Central America and the Greater Antilles. We used traditional genetic differentiation indices, Bayesian clustering and multivariate methods to create a more comprehensive picture of the genetic relationships within the species across its range. Analyses of mtDNA and microsatellite loci show evidence of a strong population genetic structure in the American crocodile, with unique populations in each sampling locality. Our results support previous findings showing large degrees of genetic differentiation between the continental and the Greater Antillean C. acutus. We report three new haplotypes unique to Venezuela, which are considerably less distant from the Central and North American haplotypes than to the Greater Antillean ones. Our findings reveal genetic population differentiation between Cuban and Jamaican C. acutus and offer the first evidence of strong genetic differentiation among the populations of Greater Antillean C. acutus.
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Crocodylus acutus american crocodile bite marks on a nest data logger
PeerJ, 2020Co-Authors: Stephanie K Drumheller, Jennifer H Nestler, Caitlin Hackett E Farris, Seth C Farris, Frank J. MazzottiAbstract:: Several data loggers deployed to monitor temperature and humidity of Crocodylus acutus (American crocodile) nests in South Florida could not be located after hatching. One badly damaged data logger was retrieved, providing insight into the possible fate of the others. Using a taphonomic approach, we identified numerous indentations, consistent with crocodylian bite marks, and inconsistent with potential mammalian or squamate bites. It seems most likely that the data logger was damaged by the nesting C. acutus rather than during attempted nest predation. Estimated bite forces for reproductive age, female C. acutus exceed the predicted material properties of the data logger's housing, suggesting that the bites were exploratory in nature. We suggest that data loggers be removed prior to hatching or permit remote data storage.
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shifts in hatching date of american crocodile Crocodylus acutus in southern florida
Journal of Thermal Biology, 2020Co-Authors: Michael S Cherkiss, Laura A Brandt, Frank J. Mazzotti, James I Watling, Jim Lindsay, Jeffrey S Beauchamp, Jerome J Lorenz, Joseph A Wasilewski, Ikuko FujisakiAbstract:Abstract Globally temperature of marine environments is on the rise and temperature plays an important role in the life-history of reptiles. In this study, we examined the relationship between sea surface temperature and average date of hatching for American crocodiles (Crocodylus acutus) over a 37-year period at two nesting sites, Everglades National Park and Florida Power and Light Turkey Point Power Plant site in southern Florida. Our results indicate that hatch dates are shifting 1.5 days earlier every two years and at half that rate for the Turkey Point site, and with every 1 °C degree increase in temperature, hatching occurs about 10 days earlier in the Everglades and 6 days earlier at Turkey Point. Our results on shifting hatch dates for American crocodiles provide further details about the impacts of temperature change on crocodile life history and suggest that increased temperature may affect their phenology.
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High levels of population genetic differentiation in the American crocodile (Crocodylus acutus)
2019Co-Authors: Natalia A Rossi, Frank J. Mazzotti, Joe Wasilewski, Byron Wilson, Kurt Mclaren, Rafael Antelo, Rafael Crespo, Angelica Menchaca-rodriguez, Fernando Alda, Ignacio DoadrioAbstract:Abstract The American crocodile ( Crocodylus acutus ) is a widely distributed species across coastal and brackish areas of the Neotropical region of the Americas and the Greater Antilles. Available information on patterns of genetic differentiation in C. acutus shows a complex structuring influenced by interspecific interactions (mainly hybridization) and anthropogenic actions (mostly historical hunting, recent poaching and unintentional translocation of individuals). Moreover, recent work suggests C. acutus as a complex of cryptic species with preliminary proposals for taxonomic reassignment. Until recently, most population genetics research has primarily focused on present hybrid zones with other new world crocodilians . In this study, we used data on mitochondrial DNA control region and 11 nuclear polymorphic microsatellite loci to assess the degree of population structure of C. acutus in South America, North America, Central America and the Greater Antilles. We used traditional genetic differentiation indices, Bayesian clustering and multivariate methods to create a more comprehensive picture of the genetic relationships within the species across its range. Analyses of mtDNA and microsatellite loci show evidence of strong population genetic structure in the American crocodile, with unique populations in each sampling locality. Our results support previous findings showing large degrees of genetic differentiation between the continental and the Greater Antillean C. acutus. We report three new haplotypes unique to Venezuela, which are considerably less distant from the Central and North American haplotypes than to the Greater Antillean ones. Our findings reveal genetic population differentiation between Cuban and Jamaican C. acutus and offer the first evidence of strong genetic differentiation among the populations of Greater Antillean C. acutus. The information generated here is crucial for local and regional planning and conservation of the species, and contributes to the ongoing discussion on potential taxonomic revision for C. acutus .
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Satellite Telemetry of Crocodylus acutus in Jamaica: Habitat Selection and Management Implications
2019Co-Authors: Jeffrey S Beauchamp, Joseph A Wasilewski, Byron Wilson, Kurt Mclaren, Lawrence P. Henriques, Frank J. MazzottiAbstract:Crocodylus acutus (American Crocodile) is primarily a coastal species that occurs in brackish wetlands, ponds, and estuarine rivers. In Jamaica, most of the moderate–high quality crocodile habitat is concentrated in isolated sections along the southern coast. Management of C. acutus in Jamaica is focused primarily on removing or translocating nuisance crocodiles to less-urbanized areas. We used satellite telemetry to understand the efficacy of translocation efforts, as well as to investigate spatial use and patterns of habitat preference. Home ranges (95% kernel density estimate; KDE) varied from 5.1 to 58.8 km2; core areas (50% KDE) varied from 1.0 to 11.9 km2; and minimum convex polygons varied from 2.2 to 33.6 km2. Crocodiles used and selected for wetland forest habitat, and selected against open water and dry forest habitats. One translocated C. acutus moved directly to a bridge where tourists and locals feed crocodiles, and 2 translocated C. acutus established home ranges in the footprint of a former proposed international shipping hub. We recommend an extensive country-wide survey, a public outreach program, an evaluation of the nuisance crocodile management plan, and strong enforcement of The Wildlife Protection Act of 1971.
Laurie A. Mauger - One of the best experts on this subject based on the ideXlab platform.
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Conservation genetics of American crocodile, Crocodylus acutus, populations in Pacific Costa Rica
Nature Conservation, 2017Co-Authors: Laurie A. Mauger, Michael S Cherkiss, Frank J. Mazzotti, Elizabeth Vélez, Matthew L. Brien, James R. SpotilaAbstract:Maintaining genetic diversity is crucial for the survival and management of threatened and endangered species. In this study, we analyzed genetic diversity and population genetic structure at neutral loci in American crocodiles, Crocodylus acutus, from several areas (Parque Nacional Marino Las Baulas, Parque Nacional Santa Rosa, Parque Nacional Palo Verde, Rio Tarcoles, and Osa Conservation Area) in Pacific Costa Rica. We genotyped 184 individuals at nine microsatellite loci to describe the genetic diversity and conservation genetics between and among populations. No population was at Hardy-Weinberg Equilibrium (HWE) over all loci tested and a small to moderate amount of inbreeding was present. Populations along the Pacific coast had an average heterozygosity of 0.572 across all loci. All populations were significantly differentiated from each other with both FST and RST measures of population differentiation with a greater degree of molecular variance (81%) found within populations. Our results suggest C. acutus populations in Pacific Costa Rica were not panmictic with moderate levels of genetic diversity. An effective management plan that maintains the connectivity between clusters is critical to the success of C. acutus in Pacific Costa Rica
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Preliminary Mating Analysis of American Crocodiles, Crocodylus acutus, in Las Baulas, Santa Rosa, and Palo Verde National Parks, Guanacaste, Costa Rica
South American Journal of Herpetology, 2015Co-Authors: Kiristin M. Budd, James R. Spotila, Laurie A. MaugerAbstract:Abstract Studying the mating system of wild populations of American crocodiles, Crocodylus acutus, has important conservation implications. We conducted a preliminary analysis of the mating system of C. acutus in Las Baulas (2007 and 2008), Santa Rosa (2007) and Palo Verde (2008 and 2009) National Parks in Guanacaste, Costa Rica. We captured hatchlings during crocodile surveys and analyzed them with nine polymorphic microsatellite loci to determine relatedness values. High relatedness values indicated that full and half siblings were sampled in a single locality and season. We found full siblings between the years that hatchlings were collected in Las Baulas and Palo Verde National Parks, which suggested mate fidelity. The mate fidelity and high relatedness values could be a consequence of the smaller number of adult crocodiles found within these areas or indicative of a small number of dominant males in the populations. Our results support the need to conduct future studies describing the mating system a...
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Population assessment of the American crocodile, Crocodylus acutus (Crocodilia: Crocodylidae) on the Pacific coast of Costa Rica
Revista de biologia tropical, 2012Co-Authors: Laurie A. Mauger, Michael S Cherkiss, Frank J. Mazzotti, Elizabeth Vélez, Matthew L. Brien, Michael Boston, James R. SpotilaAbstract:The American crocodile, Crocodylus acutus, is widely distributed in the American neotropics. It is endangered throughout most of its range and is listed as vulnerable by the International Union for the Conservation of Natural Fauna and Flora (IUCN) and on Appendix I of the Convention for the International Trade in Endangered Species of Wild Flora and Fauna (CITES). Despite this listing, there are few published reports on population status throughout most of its range. We investigated the status of the C. acutus, at several locations along the Pacific coast of Costa Rica. We carried out spotlight and nesting surveys from 2007-2009 along the Costa Rican Pacific coast in four distinct areas, coastal areas of Las Baulas (N=40) and Santa Rosa (N=9) National Parks and the Osa Conservation Area (N=13), and upriver in Palo Verde National Park (N=11). We recorded crocodile locations and standard environmental data at each observation. Encounter rates, popula- tion structure, distribution within each area and data on successful nesting (presence of hatchlings, nests, etc) were determined. We attempted to capture all crocodiles to record standard morphometrics. A total of 586 croco- diles were observed along 185.8km of survey route. The majority of animals encountered (54.9%) were either hatchlings (