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Abstract. The Tzabcan rattlesnake (Crotalus tzabcan) is endemic to the Yucatán Peninsula and is part of the C. durissus complex. Although relatively widespread, it is rather an uncommon species; therefore, little is known about its... more
Abstract. The Tzabcan rattlesnake (Crotalus tzabcan) is endemic to the Yucatán Peninsula and is part of the C. durissus complex. Although relatively widespread, it is rather an uncommon species; therefore, little is known about its natural history. Herein, we describe the diet of C. tzabcan on the basis of data from field encounters, museum specimens, and published data. Dietary samples were collected from Campeche, Quintana Roo, and Yucatán, Mexico, and literature records from Belize, representing most of the species' distribution range. Examination of 50 individuals resulted in 28 prey items obtained from 27 snakes. The diet of C. tzabcan consisted exclusively of mammals, including the orders Rodentia (86% of the prey items) and Soricomorpha (7%), and no ontogenetic shift in prey type was detected. However, an ontogenetic telescope is evident, where adults consume larger prey than juveniles but continue feeding on small prey. No sexual dimorphism in snout–vent length and total length was detected in C. tzabcan. No sexual differences in prey mass were found when controlling for snake body length, nor when comparing between sexes in adults and juveniles. The presence of prey was not related to snake collection date, suggesting year-round feeding. There was no difference in prey class and size among snakes from Yucatán dry forest and moist forest. These results suggest a homogenous diet among sexes, seasons, and populations. This is the first detailed study on the diet and feeding ecology of C. tzabcan, and it adds five new prey species: Cryptotys mayensis, Heteromys desmarestianus, H. gaumeri, Oryzomys couesi, and Rattus rattus, as well as two previously reported ones: Mus musculus and Sigmodon toltecus. These findings contrast with anecdotal reports of C. tzabcan consuming reptiles and birds and show many similarities with the related species C. durissus. Additional studies on the natural history of C. tzabcan and related species would help to better understand how the feeding ecology of Neotropical rattlesnakes differs from those species of temperate zones.
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Este estudio documenta la utilización de hábitat por reptiles en selvas mediana y baja, con tres estados sucesionales: menor de 10 años, entre 10 y 25 años y selvas maduras (> 30 años). La investigación se llevó a cabo entre abril de... more
Este estudio documenta la utilización de hábitat por reptiles en selvas mediana y baja, con tres estados sucesionales: menor de 10 años, entre 10 y 25 años y selvas maduras (> 30 años). La investigación se llevó a cabo entre abril de 1997 y enero de 1998 en la Reserva de la Biosfera Calakmul, Campeche, México. Los muestreos se realizaron a lo largo de un año para incluir las tres estaciones climáticas predominantes en la región: nortes, secas y lluvias. Utilizamos métodos complementarios de muestreo: búsqueda directa en transectos y fuera de ellos, y muestreo con trampas, para evitar sesgos. La información recabada se analizó mediante técnicas multivariadas y de ordenación, para identificar tendencias o afinidades de las especies hacia cierto estado de la vegetación. Se encontraron 10 especies en mayor abundancia y representación en al menos 5 de los 6 tratamientos, que fueron utilizadas para comparar las diferencias entre los sitios conservados de los perturbados.
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Detecting and quantifying hybridization between endangered or threatened taxa can provide valuable information with regards to conservation and management strategies. Hybridization between members of the genus Crocodylus has been known to... more
Detecting and quantifying hybridization between endangered or threatened taxa can provide valuable information with regards to conservation and management strategies. Hybridization between members of the genus Crocodylus has been known to occur in captivity and in some wild populations. We tested for hybridization among wild populations of American crocodile (C. acutus) and Morelet's crocodile (C. moreletii) in the Yucatan Peninsula by comparing Bayesian assignment tests, based on microsatellite data, to mitochondrial and morphological assignments. Skin clips from 83 individuals were taken for genetic identification, and a total of 32 individuals (38.6%) exhibited some evidence of hybridization by combined morphological, mitochondrial and microsatellite analyses. The majority of hybrids were classified as F2 hybrids and backcrosses to C. moreletii. Most of the introgression occurs in two national biosphere reserves located on the northern and eastern coasts of the Yucatan Peninsula. Preliminary tests did not find a significant decrease in hybridity across three life stages, thus far indicating a low level of selection against hybrids. Model‐based analyses on multilocus genotypes of pure individuals returned little geographic partitioning in both C. acutus and C. moreletii. J. Exp. Zool. 309A:674–686, 2008. © 2008 Wiley‐Liss, Inc.
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Actualmente, los ecosistemas enfrentan una gran pérdida de biodiversidad debido a perturbaciones antrópicas, lo cual que tiene efectos negativos en los procesos ecológicos. Para conocer el estado de conservación de un ambiente se pueden... more
Actualmente, los ecosistemas enfrentan una gran pérdida de biodiversidad debido a perturbaciones antrópicas, lo cual que tiene efectos negativos en los procesos ecológicos. Para conocer el estado de conservación de un ambiente se pueden determinar especies indicadoras, que desempeñan un rol importante en distintos procesos ecológicos y son sensibles a los disturbios. El objetivo de este estudio fue determinar la diversidad y composición de aves en respuesta a diferentes perturbaciones del hábitat en el ejido Laguna Om, Quintana Roo, México, mediante conteo por puntos de agosto a septiembre de 2017. Se seleccionaron hábitats con diferente estado de conservación denominados: Selva, Laguna, Carretera, Potrero y Helechal. La mayor riqueza de especies se registró en los hábitats de Laguna y Carretera. Los patrones de abundancia de especies tolerantes a la perturbación fueron mayores en las áreas perturbadas. Encontramos mayor similitud en la composición de los gremios tróficos de las esp...
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Resumen Las carreteras y el tránsito vehicular tienen impactos negativos de diversa índole en la fauna silvestre. Aquí reportamos un posible intento de depredación de una víbora de cascabel yucateca (Crotalus tzabcan) por un mapache... more
Resumen Las carreteras y el tránsito vehicular tienen impactos negativos de diversa índole en la fauna silvestre. Aquí reportamos un posible intento de depredación de una víbora de cascabel yucateca (Crotalus tzabcan) por un mapache (Procyon lotor). Esta observación se realizó durante un estudio de monitoreo de serpientes atropelladas en Quintana Roo, México. Palabras clave: Carreteras, cascabel yucateca, depredación, mapache.
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This study focused on the relationship between the perceptions and attitudes of visitors at the Jardín Zoológico Payo Obispo and their support for the conservation of nine animal species, native of southeastern Mexico. Results from 198... more
This study focused on the relationship between the perceptions and attitudes of visitors at the Jardín Zoológico Payo Obispo and their support for the conservation of nine animal species, native of southeastern Mexico. Results from 198 surveys applied from November 2018 to February 2019, show that fear is the most important factor for visitors to decide if they support the protection of opossums and boas, while for ferruginous pygmy-owl and Morelet’s crocodile it was the aesthetic consideration (“ugly”). For the remainder species, with the exception of the jicotea turtle, both, the fear, and the aesthetic perceptions directly influence conservation support.
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Members of the Crotalus durissus species complex are widely distributed from Mexico to Argentina in areas with mainly seasonally dry tropical deciduous forest. Although four species (C. culminatus, C. durissus, C. simus and C. tzabcan)... more
Members of the Crotalus durissus species complex are widely distributed from Mexico to Argentina in areas with mainly seasonally dry tropical deciduous forest. Although four species (C. culminatus, C. durissus, C. simus and C. tzabcan) are currently recognized, species limits remain to be tested. Previous genetic studies suggest that C. durissus and C. simus may be paraphyletic and that at least one cryptic species may be present. We analyzed 2596 bp of DNA sequence data from three mitochondrial and one nuclear gene to infer phylogenetic relationships in the Neotropical rattlesnakes. We also examined museum and wild specimens as well as captive animals to analyze morphological characters. Our results suggest that the current taxonomy of the Crotalus durissus species complex does not reflect evolutionary history. We found strong support for five independent lineages within Crotalus simus (sensu lato), with genetic and morphological evidence for three previously recognized taxa and tw...
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ABSTRACT We conducted spotlight surveys between February 2005 and July 2006 in five lagoons of the Esmeralda lagoon system to estimate abundance and population structure of Morelet’s Crocodile. A total of 287 crocodiles were sighted along... more
ABSTRACT We conducted spotlight surveys between February 2005 and July 2006 in five lagoons of the Esmeralda lagoon system to estimate abundance and population structure of Morelet’s Crocodile. A total of 287 crocodiles were sighted along 8.3 km of survey routes. Encounter rates ranged from 6.1 to 44.4 ind/km, and adults were the most abundant (33.5%), followed by juveniles (13.6%), while hatchlings (<30 cm TL) and subadults were less represented (8.2% and 7.5%, respectively). The sex ratio of this population (n=42; seven hatchling were excluded) does not differ from parity (1:1). Our findings indicate that Morelet’s Crocodile population is in a good condition in the study area. This study provides baseline information to initiate use of the species, following a program of management and monitoring to ensure the persistence of this healthy population in the long term.
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The variation in temperament among animals has consequences for evolution and ecology. One of the primary effects of consistent behavioral differences is on reproduction. In chelonians some authors have focused on the study of temperament... more
The variation in temperament among animals has consequences for evolution and ecology. One of the primary effects of consistent behavioral differences is on reproduction. In chelonians some authors have focused on the study of temperament using different methods. In our research our first aim was i) establish a methodology to determine the degree of boldness among individuals Rhinoclemmys areolata. Our second aim was to ii) determine the role boldness plays during reproduction, with emphasis on courtship and copulation, considering a) the interactions between males and females, and b) competition between males. We used 16 sexually mature individuals of each sex. Males were observed in four different situations and 17 behavioral traits were recorded. We selected 12 traits that allowed us distinguish between the bolder and the shier individuals and found that five behavioral traits were specific for bolder individuals and five others for shier individuals. In a second step, we observe...
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abstract: Herein, we present the first Mexican record of Morelet's crocodile, Crocodylus moreletii, as a host for the proboscis-bearing leech, Haementeria acuecueyetzin. From November 2004 to October 2017, we captured 111 crocodiles... more
abstract: Herein, we present the first Mexican record of Morelet's crocodile, Crocodylus moreletii, as a host for the proboscis-bearing leech, Haementeria acuecueyetzin. From November 2004 to October 2017, we captured 111 crocodiles during spotlight surveys in lagoons of the Dziuché ejido, municipality of José María Morelos, Quintana Roo, Mexico. Twenty-one (18.9%) individuals had leeches identified as H. acuecueyetzin. It is the first report of H. acuecueyetzin for the State of Quintana Roo, Mexico, and the northernmost record of the species. This is also the second case of leech parasitism in C. moreletii. Haementeria acuecueyetzin likely parasitize a large array of vertebrates, and its role as a potential vector of blood parasites in C. moreletii requires further investigation.
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The male of Craugastor yucatanensis (Lynch, 1965) is described for the first time, as the original description was based on four females. The advertisement call is described and additional morphological data on females are presented.... more
The male of Craugastor yucatanensis (Lynch, 1965) is described for the first time, as the original description was based on four females. The advertisement call is described and additional morphological data on females are presented. Also, information is provided on the sexual dimorphism and natural history of the species.
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Figure 1 from: Carbajal-Márquez RA, Díaz-Gamboa LF, Ramírez-Valverde T, García-Balderas CM, Nahuat-Cervera PE, Cedeño-Vázquez JR (2019) Description of the male ofCraugastor yucatanensisLynch, 1965 (Anura, Craugastoridae), advertisement call, and additional data on females. ZooKeys 900: 129-139. h...more
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Se describe la distribución geográfica de cuatro especies de serpientes venenosas (Bothriechis aurifer, Crotalus simus, Micrurus diastema y M. elegans) que habitan en el área sureste de la Altiplanicie de Chiapas. Estas especies se... more
Se describe la distribución geográfica de cuatro especies de serpientes venenosas (Bothriechis aurifer, Crotalus simus, Micrurus diastema y M. elegans) que habitan en el área sureste de la Altiplanicie de Chiapas. Estas especies se encuentran en alguna categoría de riesgo en la NOM-059-SEMARNAT-2010, se desconoce su distribución precisa y son de importancia médica. Los modelos de distribución se obtuvieron usando el algoritmo MaxEnt, para ello se usaron registros de museos nacionales y del extranjero, así como búsquedas en internet, en la literatura científica y muestreos en campo. También se realizaron entrevistas para determinar la percepción y la relación que tienen las serpientes venenosas con las poblaciones humanas. Además, se determinó la representatividad de cada una de las especies en las áreas naturales protegidas. Algunas barreras geográficas, como el Valle de Motagua, limitan la distribución de M. elegans y B. aurifer, mientras que el Istmo de Tehuantepec lo hace para C....
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The heterospecific amplex between Triprion petasatus and Incilius valliceps is documented for the first time in the locality of Piste, Yucatan Mexico. This behavior has been documented previously in other amphibians, many of them also... more
The heterospecific amplex between Triprion petasatus and Incilius valliceps is documented for the first time in the locality of Piste, Yucatan Mexico. This behavior has been documented previously in other amphibians, many of them also explosive reproducers that take advantage of temporary bodies of water, in places with a marked dry season.
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Crocodylus moreletii inhabits freshwater wetlands throughout much of the Atlantic lowlands of Mexico, Guatemala, and Belize (Groombridge 1987. In Webb et al. [eds.], Wildlife Management: Crocodiles and Alligators, pp. 9–21. Surrey Beatty... more
Crocodylus moreletii inhabits freshwater wetlands throughout much of the Atlantic lowlands of Mexico, Guatemala, and Belize (Groombridge 1987. In Webb et al. [eds.], Wildlife Management: Crocodiles and Alligators, pp. 9–21. Surrey Beatty & Sons, Pty. Ltd, Sydney). On 18 April 2013 at 2230 h, while conducting a crocodile spotlight survey along the Río Hondo (17.9°N, 88.86°W, datum WGS84; 5 m elev.) on the border between Mexico and Belize, we found a yearling Morelet’s Crocodile (32 cm total length, 130 g) that had just captured an adult male Mexican Greater Funnel-eared Bat (Natalus mexicanus) near shore. The young crocodile continued holding the bat between its jaws after we captured it (Fig. 1). Crocodilians are mainly nocturnal hunters, so field observations on actual prey species taken are scarce. However, Crocodylus porosus and C. johnstoni catch flying foxes and other bats in some regions of Australia (Pooley 1989. In Ross [ed.], Crocodiles and Alligators, pp. 76–91. Facts On F...
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ABSTRACT Body condition indices (CI) are useful tools as indicators of the health, nutrition, and life history of the individuals in a population. Healthy individuals with high energy reserves have more probabilities to breed; therefore,... more
ABSTRACT Body condition indices (CI) are useful tools as indicators of the health, nutrition, and life history of the individuals in a population. Healthy individuals with high energy reserves have more probabilities to breed; therefore, good body conditions are essential in order to preserve populations and the ecosystem functioning. Morelet’s crocodile (Crocodylus moreletii) is a key species for the stability of the ecosystem. However, studies about the health of its populations are quite scarce. The aim of this research was to determine the CI of the population of C. moreletii in the Hondo River, through the application of Fulton’s “K” condition factor (CF). During two survey periods (April-September 2002, and June 2009 to February 2010), we conducted spotlight counts aboard a 4.5 m-long aluminum boat in six sections of the river. We analyzed 200 crocodiles, most of which (n=177) had a good body condition (mean K = 41.63), which denotes a healthy population. ANOVA tests applied to mean CF values revealed significant differences (P<0.05) between survey sections, and age classes, but no significant differences between males and females (P>0.05) in both periods. Monitoring of CF in the C. moreletii population is important for the improvement of the conservation and management actions for the species and its habitat, and must be considered in future research.
The aim of this study was to determine concentrations of heavy metals (cadmium [Cd] and mercury [Hg]) and metallothioneins (MTs) in blood plasma and caudal scutes of Morelet's crocodile (Crocodylus moreletii) from Rio Hondo, a river... more
The aim of this study was to determine concentrations of heavy metals (cadmium [Cd] and mercury [Hg]) and metallothioneins (MTs) in blood plasma and caudal scutes of Morelet's crocodile (Crocodylus moreletii) from Rio Hondo, a river and natural border between Mexico and Belize. Three transects of the river (approximately 20 km each) were surveyed in September 2012 and April 2013, and samples were collected from 24 crocodiles from these areas. In blood plasma, Cd (7.6 ± 9.6 ng/ml) was detected in 69 % of samples (n = 9); Hg (12.2 ± 9.2 ng/ml) was detected in 46 % of samples (n = 6); and MTs (10,900 ± 9,400 ng/ml) were detected in 92 % of samples (n = 12). In caudal scutes samples, Cd (31.7 ± 39.4 ng/g) was detected in 84 % of samples (n = 12) and Hg (374.1 ± 429.4 ng/g) in 83 % of samples (n = 20). No MTs were detected in caudal scutes. Hg concentrations in scutes from the Rio Hondo were 2- to 5-fold greater than those previously reported in scutes from other localities in northe...