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Copyright of Dilemas Contemporáneos: Educación, Política y Valores is the property of Dilemas Contemporaneos: Educacion, Politica y Valores and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Crocodylus moreletii representa un emblema para los ecosistemas tropicales de México pero actualmente está amenazada por extinción. Sorprendentemente, hay una falta de información de su constitución genética, que debe ser evaluada para un manejo apropiado ex situ y para toma de decisiones en la liberación de cocodrilos a su hábitat natural. El objetivo del estudio fue caracterizar y comparar la variabilidad genética de cuatro grupos poblacionales de C. moreletii (dos silvestres y dos nacidas ex situ). Mediante PCR se amplificaron siete loci de microsatélites polimórficos, sin embargo se encontró déficit de heterocigotos en las poblaciones (promedio H O=0.02) mermado por la presencia de alelos nulos. El AMOVA indicó que la mayor proporción de variabilidad genética se encuentra dentro de las poblaciones y una limitada diferenciación genética entre poblaciones (promedio F ST =0.03), probablemente debida al alto índice de endogamia (promedio F IS=0.97). Al comparar la variabilidad genética inter e intra especies de cocodrilianos, encontramos que en C. moreletii está muy por debajo de los reportados. Se concluye que la limitada variabilidad genética de las poblaciones nacidas ex situ probablemente se debe al efecto fundador derivado de la estructura social de sus progenitores, y de las poblaciones silvestres, por el efecto cuello de botella, inferido por el limitado tamaño efectivo de población que presentó históricamente en su distribución natural.

El objetivo del trabajo fue evaluar la variabilidad morfológica y el crecimiento corporal de 4 poblaciones del cocodrilo de pantano (Crocodylus moreletii) que se encuentran en la Unidad de Manejo para la Conservación de la Vida Silvestre Cacahuatal ubicada en el estado de Veracruz, México. Se compararon 4 poblaciones: 2 poblaciones cuyos individuos nacieron en vida silvestre y 2 que nacieron en cautiverio. Los rasgos morfológicos estudiados fueron similares entre poblaciones y entre sexos. Las tasas de crecimiento corporal fueron significativamente diferentes entre poblaciones. Los individuos que nacieron en condiciones naturales crecieron más rápidamente que los nacidos en cautiverio. Se concluye que el cautiverio no parece afectar la expresión morfológica, pero sí la tasa de crecimiento corporal. Estos resultados muestran que diferentes poblaciones de C. moreletii pueden presentar un crecimiento diferencial determinado por las condiciones de cautiverio.The main goal of this study was to evaluate the effect of captivity upon morphological characteristics and body growth rates of the Morelet's crocodile (Crocodylus moreletii). The studied individuals are currently reared in the Management Unit for Wildlife Conservation (Cacahuatal), located at Veracruz, Mexico. Four populations were compared: individuals from 2 of them were born in wild conditions, whereas individuals from the other 2, were born in captivity. Morphology was similar among populations and between sexes. Body growth rates were significantly different among populations, those individuals born in natural conditions grew faster than those born in captivity. We conclude that captivity does not seem to affect the morphological expression of C. moreletii in comparison with a significant effect upon the rate of body growth. These results show that different populations of C. moreletii can exhibit differential body growth patterns depending on the conditions experienced in captivity.

Nesting ecology of Morelet's crocodile (Crocodylus moreletii) has been documented since 1940. However, only 2 nests constructed on floating vegetation have been recorded. Here, we presented additional information from a mainland population of C. moreletii in the Ciénega de Cabezas wetland, San Luis Potosí, describing 2 nests constructed on floating mats of cattails. The nests were constructed using Typha sp., close to the main channel. One nest was lost due to flooding, and contained 32 eggs. Seven eggs had a mean 72.6 ± 2.63 mm length (range = 70.0 -75.0 mm), 45.0 ± 2.30 mm width (range = 41.0-48.0 mm), and 140.7 ± 2.98 mm diameter (range = 136.0-145.0 mm). We suggest that the use of floating vegetation for nesting by C. moreletii is related to the availability of aquatic vegetation, combined with the lack of adequate nesting sites on land.La ecología de anidación del cocodrilo de pantano (Crocodylus moreletii) ha sido documentada desde 1940. Sin embargo, sólo existen 2 registros de nidos construidos sobre vegetación acuática. Presentamos información adicional de 2 nidos (N1 y N2) construidos en este tipo de hábitat en una población ubicada en la Ciénega de Cabezas en el estado de San Luis Potosí. Los nidos fueron construidos sobre Typha sp., cerca del cauce principal de la ciénega. El N2 se perdió por inundación, en su interior encontramos 32 huevos, los promedios (± SD) del largo, ancho y diámetro de 7 huevos fueron 72.6 ± 2.63 mm (rango = 70.0 -75.0 mm), 45.0 ± 2.30 mm (rango = 41.0-48.0 mm), 140.7 ± 2.98 mm (rango = 136.0-145.0 mm), respectivamente. Sugerimos que este tipo de sitios para anidar por parte de C. moreletii está relacionado con la disponibilidad de vegetación acuática, combinado con la ausencia de sitios adecuados en tierra firme.

Crocodylus moreletii is a species of commercial interest based on its skin. In this study, five morphological traits of commercial interest were characterized in 125 captivity-raised specimens of C. moreletii from four populations (Puente Chilapa, Gutiérrez Zamora, Villa Juárez and Puerto Vallarta). A canonical discriminant analysis (CDA) was used to differentiate the populations according to their morphological traits, a cluster analysis (CA) was used to infer which populations had the largest total length (TL), and a covariance analysis (ANCOVA) was used to assess the allometry and detect which population was different in terms of TL. The CDA showed no significant effects, suggesting that the morphological traits were similar among populations; the CA grouped two populations which had the largest body size; the ANCOVA revealed a significant correlation between morphological traits and detected a TL effect significantly lower in males and females from Puente Chilapa, in comparison with the other three populations. In conclusion, the males from Gutiérrez Zamora and the females from Villa Juárez were morphologically outstanding in terms of TL, and they would be the right crocodiles to establish a breeding nucleus in order to obtain offspring with their phenotypic characteristics.

Crocodylus moreletii, an extinction threatened species, represents an emblem for tropical ecosystems in Mexico. Surprisingly, there is a lack of information about their genetic constitution, which should be evaluated for a proper management ex situ and for making decisions on the release of crocodiles into natural habitats. The aim of this study was to characterize and compare the genetic variability of four populations of C. moreletii (two wild versus two born ex situ). Through PCR were amplified seven microsatellite polymorphic loci, however a heterozygote deficit, diminished by the presence of null alleles, was found in the populations (average HO=0.02). The AMOVA indicated that the highest proportion of genetic variability is within populations, and a limited genetic differentiation among populations (average FST=0.03), probably due to high inbreeding index (average FIS=0.97). When comparing the genetic variability between and within other crocodilian species, we found that in C. moreletii is well below those reported. We concluded that the limited genetic variability in ex situ born populations is probably due to a founder effect derived from the social structure of their progenitors, and by the bottleneck effect, inferred by the limited effective population size, that historically characterizes their natural distribution in wild populations. [ABSTRACT FROM AUTHOR]

Copyright of Revista Mexicana de Biodiversidad is the property of Universidad Nacional Autonoma de Mexico, Instituto de Biologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Mexicana de Biodiversidad is the property of Universidad Nacional Autonoma de Mexico, Instituto de Biologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)