Resumen En ausencia de un manejo sustentable, diversas comunidades rurales explotan los recursos naturales de sus alrededores, lo anterior puede causar un impacto directo en las poblaciones silvestres. Aquí registramos el uso de la Iguana Negra de Cola Espinosa (Ctenosaura pectinata) como fuente de alimento por una comunidad del Centro de México.

Abstract In the absence of sustainable management, several rural communities exploit the natural resources of their surroundings, which can cause a direct impact on wild population. Here we report the use of the Black Spiny-tailed Iguana (Ctenosaura pectinata) as a food source by a community in central Mexico.

Abstract In oviparous lizards there is a frequent interval in the embryonic development that the eggs reach at the time of oviposition between stage 26 and 33. This variation has been related to the origin of viviparity and allowing the exploration of the effects of specific experimental conditions on embryonic development after oviposition. However, for most species of lizards the embryonic stage at oviposition is unknown. The present study details for first time in Corytophanidae the embryonic stage at oviposition of Basiliscus vittatus. Gravid females were collected to obtain recently oviposited clutches. From each clutch, a random egg was dissected in order to determine the embryonic stage at oviposition, in addition to measuring morphometric variables of the female and the eggs. Our results show that in B. vittatus, females oviposit in 4 embryonic stages: 29 to 32; however, there is a preference for ovipositing in intermediate embryonic stages (stages 30 and 31). Of the different variables recorded, the stages at oviposition are associated with the maximum length of the egg. The stage at oviposition of B. vittatus seems to be related to physiological and morphological factors of the females, as well as their foraging strategy.

Resumen En lagartijas ovíparas existe un intervalo frecuente en el desarrollo embrionario que alcanzan los huevos al momento de la oviposición entre el estadio 26 y 33. Dicha variación se ha relacionado con el origen de la viviparidad y permite la exploración de los efectos experimentales en el desarrollo embrionario después de la oviposición. Sin embargo, para la mayoría de las especies de lagartijas, el estadio embrionario en la oviposición es desconocido. El presente estudio detalla por primera vez en Corytophanidae el estadio embrionario en la oviposición de Basiliscus vittatus. Se colectaron hembras grávidas para obtener nidadas de reciente oviposición. De cada nidada, un huevo al azar fue disecado con la finalidad de determinar el estadio embrionario en la oviposición, además de medir variables morfométricas de la hembra y de los huevos. Los resultados muestran que en B. vittatus, las hembras ovipositan en 4 estadios embrionarios: 29 a 32; sin embargo, existe una preferencia por ovipositar en estadios embrionarios intermedios (estadios 30 y 31). De las diferentes variables registradas, el estadio en la oviposición solo se asocia con el largo máximo del huevo. El estadio en la oviposición de B. vittatus parece estar relacionado con factores fisiológicos y morfológicos de las hembras, así como por su estrategia de forrajeo.

RESUMEN Mamíferos depredan masivamente anuros cuando éstos se congregan en sitios de reproducción. Se registró depredación masiva de Incilius occidentalis caracterizada por la presencia de múltiples individuos muertos carentes de vísceras y extremidades, pero con la cabeza y las glándulas parótidas presentes. La evidencia sugiere que este evento ocurrió por el depredador Procyon lotor.

ABSTRACT Anurans are subject to large scale prédation during congregation at breeding sites by mammalian species. Massive predation of Incilius occidentalis was recorded. Individuals were characterized by lacking viscera and appendages; however, the head and parotid glands remained intact. It is suggested that this event occurred by the predator Procyon lotor.

Abstract: Clutch size, relative clutch mass and traits of hatchlings are important life history traits. The present study provides information on clutch size, relative clutch mass and traits of hatchlings of a population of Phrynosoma orbiculare occurring in the Parque Estatal Sierra Morelos, Toluca, Estado de México (± 2,700 m asl). Gravid females (n = 14) having SVL of 75.2 ± 2.3 mm produced clutch sizes of 8.3 ± 0.6 hatchlings, and relative clutch masses of 27.2 ± 1.5 g. Females of greater size and weight had higher numbers of live-born offspring, a common situation in lizards of temperate habitats, whereas lighter weight females had higher relative clutch mass than heavier females; both results have been recorded in lizards, including species of Phrynosoma. Neonates had SVL of 26.1 ± 0.1 mm, and weights of 1.1 ± 0.01 g (without sexual difference), we found a very low variation in both traits; the sex ratio was 1:1.

Resumen: El tamaño y masa relativa de la camada y las particularidades de las crías son características importantes de historia de vida. El presente estudio aporta información sobre el tamaño y masa relativa de la camada y características de las crías de Phrynosoma orbiculare en el Parque Estatal Sierra Morelos, Toluca, Estado de México (± 2,700 m snm). Las hembras gestantes tuvieron una LHC de 75.2 ± 2.3 mm (n = 14), con un tamaño de camada de 8.3 ± 0.6 crías y una masa relativa de la camada de 27.2 ± 1.5 g. Las hembras de mayor talla y peso tuvieron un mayor número de crías, una situación común en lagartijas de ambientes templados; sin embargo, las hembras más ligeras tuvieron una mayor masa relativa de la camada que hembras de mayor peso; ambos resultados han sido registrados en lagartijas, incluyendo especies del género Phrynosoma. Las crías tuvieron una LHC de 26.1 ± 0.1 mm y un peso de 1.1 ± 0.01 g (sin diferencia sexual) y existe una variación baja en ambas características; la proporción sexual fue 1:1.

Abstract: Female reproductive cycle and clutch size are important life history traits in lizards that can be influenced by biotic and/or abiotic factors. Here, the ovarian cycle and clutch size of a high-elevation population (1500-1600 m) of Aspidoscelis costata costata in Central Mexico are described. Females were collected monthly between 2005 and 2007, and their reproductive condition was evaluated based on appearance and size of ovarian follicles and presence/absence of oviductal eggs. The reproductive cycle was markedly seasonal with asynchrony in reproductive condition among females. Vitellogenic and gravid females were recorded from April (end of the dry season) through July (middle of the rainy season). Although this population inhabits a semi-humid warm climate, the timing of female reproduction in A. costata costata is similar to the cycle of temperate-zone species of Aspidoscelis. Females produced a single clutch annually with an average clutch size of 7.7 ± 0.44 eggs (median 8 eggs, range 4-14), which is the largest reported to date within the genus Aspidoscelis.

Resumen: El ciclo reproductor de las hembras y el tamaño de nidada en lagartijas son características importantes de historia de vida que pueden ser influenciadas por factores bióticos y/o abióticos. En este trabajo se describen el ciclo ovárico y el tamaño de nidada de Aspidoscelis costata costata en una población de elevación alta (1,500-1,600 m) del centro de México. Las hembras se recolectaron mensualmente entre 2005 y 2007 y se evaluó su condición reproductora con base en la apariencia y tamaño de los folículos ováricos, y la presencia o ausencia de huevos oviductales. El ciclo reproductor fue marcadamente estacional con asincronía ovárica entre las hembras. Hembras vitelogénicas y grávidas se registraron desde abril (final de la estación de sequía) hasta julio (mediados de la estación de lluvias). No obstante que esta población habita en un clima cálido sub-húmedo, el ciclo reproductor en las hembras de A. costata costata es similar al ciclo de las especies de Aspidoscelis de zonas templadas. Las hembras producen una sola nidada anualmente con un tamaño de nidada promedio de 7.7 ± 0.44 huevos (mediana 8 huevos, intervalo 4-14), que es el más alto registrado dentro del género Aspidoscelis.

Home range is defined as the area within which an individual moves to acquire resources necessary to increase their fitness and may vary inter and intra-specifically with biotic and abiotic factors. This study details the home range of the parthenogenic lizard, Aspidoscelis cozumela,an active forager microendemic to Cozumel Island, México, with high preference for open sand beaches. The home range of A. cozumelawas compared with other species of Aspidoscelis(gonochoric and parthenogenetic) and other lizards that occupy coastal habitats. Furthermore, the biotic and abiotic factors that may influence home range were analyzed. This study was conducted in the beach located on the East side of the island (area of 4 000 m2) that is composed primarily of halophyte vegetation with high levels of sunlight. From 1999 to 2001, nine samples were taken which included the dry, rainy, "nortes", and breeding seasons. During each sampling, capture-mark-recapture techniques were conducted and the date, time of day, and snout-vent length (SVL) were recorded to the nearest millimeter. Individuals were located in the study area using a bi-coordinate reference using 10 x 10 m subdivisions of the habitat. Home range and home range overlap were calculated using the convex polygon method in McPaal and home range/SVL correlation was tested using Pearson's correlation. To calculate females home range, three or more recaptures were considered. A total of 20 home ranges that averaged 45.1 ± 14.0 m2 were obtained and no correlation between SVL and home range size was detected (p = 0.9229, n = 20). However, removing individuals with outlier home ranges (females with home ranges > 100 m2, n = 2) resulted in a positive correlation with SVL (r = 0.61, p = 0.0072, n = 18). A 22.9 ± 5.7% overlap in home range was also detected. The small home range of A. cozumelarepresents the smallest home range within the Aspidoscelisgenus recorded to date (including both parthenogenetic and gonochoric species) and contrasts the theoretical predictions of broad home ranges for widely foraging species. Thermoregulatory benefits and a high population density may explain the small home range of A. cozumela.Although this species is highly adapted to the environmental conditions present on the open sand beaches, anthropogenic effects on these habitats by the development of tourism infrastructure may jeopardize their existence on Cozumel Island.

En lagartijas la coloración corporal es importanteen la comunicación así como en la protección contra los depredadores. Con el uso de una guía Pantone®, se analizó el cambio estacional en la coloración dorsal y los microhábitats de Aspidoscelis costata costata, una lagartija de amplio forrajeo que habita un ambiente (en el Estado de México, México) que cambia drásticamente de apariencia entre sequía y lluvias. Se analizó la dependencia de la coloración dorsal de acuerdo a la estación, sexo y estadio de desarrollo. Los resultados indican que la lagartija A. costata costata presenta una coloración dorsal similar al sustrato en cada estación: parda en sequía y principalmente verde en lluvias. Este estudio sugiere: 1) Que la variación en coloración dorsal con funciones crípticas, como la registrada en A. costata costata, puede resultar importante en la supervivencia de especies de amplio forrajeo; 2) Que el cambio en la coloración dorsal en A. costata costata es a nivel individual, ya que un individuo presente en ambas estaciones manifiesta una coloración dorsal parda en la estación de sequía y una coloración dorsal verde en la estación de lluvias y 3) Que la coloración dorsal, con funciones crípticas, está subestimada en especies de amplio forrajeo.

Seasonal changes in the dorsal coloration in the lizard Aspidoscelis costata costata (Squamata: Teiidae). Color and color patterns in animals are important characteristics that bring protection, by dampening the ability of predators that depend on their sight to detect their preys. In lizards, the dorsal coloration plays a key role in communication of intraspecific signals such as social cues. In this study, we evaluated the seasonal changes in the dorsal coloration of the wide foraging lizard A. costata costata, in Tonatico, State of Mexico, Mexico. The seasonal evaluation included: the rainy season from mid June to mid September (can also include the end of May to early October); and the dry season for the rest of the year. The dorsal coloration of A. costata costata and their microhabitats were evaluated by contrasting the color pattern with an identification guide and the control colors of Pantone®, during 11 samplings carried out from February-October 2007. Individual lizard analysis recorded snout-vent length, sex and stage (juveniles and adults). Besides, all animals were marked by toe-clipping, allowing to distinguish dorsal coloration between seasons, sex and stage. A total of 95 lizards were analyzed (53 and 42 for the dry and rainy seasons respectively). We found that the dorsal coloration in A. costata costata varies seasonally and with microhabitats: during the dry season individuals show a brown coloration whereas during the rainy season becomes greener, as the background dominant vegetation color. The results of the present study suggest that: 1) the variation in dorsal coloration in A. costata costata plays an important role in the survival (by cryptic camouflage) of this widely foraging species; 2) the changes in the dorsal coloration of A. costata costata are individually expressed traits, since the coloration of the same lizard is either brown or green depending on the season; and 3) the cryptic functions of the dorsal coloration in widely foraging species have been largely underestimated. We discuss the possible influence of the changes in coloration in an habitat that changes drastically between both dry and rainy seasons.

Sexual dimorphism is a widespread characteristic in lizards, and it has been related to the individual fitness. Sexual dimorphism was investigated in Aspidoscelis costata costata (Squamata) to the south of the State of Mexico, Mexico, relating to its body proportions highly similar within the Teiidae. Study area was located at 1500 m. Adult individuals from mark-recapture study were used. Morphometric characteristics were measured in individuals of A. costata costata: snout-vent length, mass, head length, head width, head height, femur length and interlimb length. Males were larger than females for SVL and mass. At the same body, males had longer heads and femur and shorter interlimb length than did conspecific females. The sexual dimorphism of A. costata costata can be explained by selection sexual selection and fecundity selection.

El dimorfismo sexual es una característica extendida en lacertilios y se relaciona con la adecuación de los individuos. En este estudio se analizó si Aspidoscelis costata costata (Squamata) presenta dimorfismo sexual al sur del Estado de México, México, especialmente en relación a su forma corporal altamente conservada dentro de la familia Teiidae. La población estudiada habita a 1500 msnm. Se utilizaron individuos adultos que fueron capturados y liberados durante estudios ecológicos. Para cada individuo se registró la longitud hocico-cloaca, el peso corporal, largo de la cabeza, ancho de la cabeza, alto de la cabeza, longitud del fémur y distancia interaxilar. Los análisis realizados indicaron que los machos fueron más grandes en longitud hocico-cloaca y peso; además presentaron dimensiones más grandes en cabeza y fémur que hembras de la misma longitud hocico-cloaca. La distancia interaxilar fue mayor en hembras que en machos de la misma longitud hocico-cloaca. El dimorfismo sexual de A. costata costata puede explicarse por selección sexual y selección por fecundidad.

La divergencia post-formación se ha utilizado para el reconocimiento de nuevas especies partenogenéticas. Actualmente, la lagartija partenogenética Aspidoscelis rodecki McCoy y Maslin 1962 es reconocida como una sola especie, que se originó de un híbrido partenogenético. Estudios previos han encontrado divergencia genética, en coloración y en características de historia de vida entre una población continental (Puerto Juárez) y una insular (Isla Contoy) en Quintana Roo, México. Se llevó a cabo un análisis merístico para evaluar la divergencia entre ambas poblaciones de A. rodecki. Se utilizaron 38 individuos de Puerto Juárez y 23 individuos de Isla Contoy. Se usaron nueve características merísticas y se realizaron análisis univariados (t de Student) y multivariados (análisis de componentes principales y análisis de variación canónica). De acuerdo a ambos análisis, Puerto Juárez es merísticamente distinguible de Isla Contoy. Ambas poblaciones difieren en cinco características merísticas y presentaron un alto porcentaje de clasificación en el análisis de variación canónica: 97% para Puerto Juárez y 100% para Isla Contoy. Una pequeña muestra de Isla Mujeres y un solo individuo de Punta Sam (continente) pueden representar otros grupos morfológicos. Con base en los patrones de variación fenotípica, A. rodecki es considerada como una sola especie partenogenética variable y prioritaria para la conservación. Debido a que cada población contiene una porción única de la variación de A. rodecki, Puerto Juárez e Isla Contoy merecen un manejo separado y se sugiere que cada una constituya una "Unidad Evolutiva Significativa" (ESU).

Morphologic variation of the parthenogenetic lizard Aspidoscelis rodecki (Squamata: Teiidae): evolutionary and conservation implications. Post-formational divergence has been used for the recognition of new parthenogenetic species. Currently, the parthenogenetic lizard Aspidoscelis rodecki McCoy and Maslin 1962 is recognized as a single taxon that was derived from a single, parthenogenetically capable, hybrid. This lizard had been derived via hybridization between individuals of two gonochoristic species, Aspidoscelis angusticeps Cope 1878 and Aspidoscelis deppii Wiegmann 1834. The distribution of A. rodecki includes Isla Contoy and Isla Mujeres and the adjacent mainland of Quintana Roo, México. Previous studies have found post-formational divergence in genetic, chromatic and life-history characteristics among a continental population (Puerto Juárez) and an insular population (Isla Contoy). A meristic analysis was carried out to evaluate the morphological divergence among both populations of A. rodecki. We used 38 individuals from Puerto Juárez and 23 individuals from Isla Contoy. Nine meristic characters with discrimination value among species of the genus Aspidoscelis were used in both univariate (t-Student) and multivariate analyses (principal components and canonical variate analysis). According to both analyses, Puerto Juárez is meristically distinguishable from Isla Contoy. Both populations differ in five meristic characters and were a high correct classification in the canonical variate analysis: 97% of Puerto Juárez and 100% of Isla Contoy. A small sample from Isla Mujeres and a single specimen from Punta Sam (mainland) may represent different morphological groups. Due to the patterns of phenotypic variation, A. rodecki is considered as a single variable parthenogenetic species with high priority to conservation. The populations of A. rodecki have been extremely affected by the tourism developers. If the habitat of the parthenogenetic lizard (beach grasses) is allowed to stay, the expansion by the developers will not affect the survivorship of these populations. Nevertheless, the first sign of development is the total destruction of natural grasses that occurs on the beach, leaving only sand. There is a last chance to save the parthenogenetic lizard A. rodecki, but any effort will be useless without the support from the environmental authority of Mexico and cooperation from the developers. We suggest that Puerto Juárez and Isla Contoy receive separate management because they have unique portions of phenotypic variation of A. rodecki. The two lizard populations can be considered separate "Evolutionary Significant Units" (ESU). Rev. Biol. Trop. 56 (4): 1871-1881. Epub 2008 December 12.