Reproductive strategies can be characterized according to how often and when females reproduce, how much they invest, and how reproductive investment is distributed. Plasticity can lead to changes in reproductive strategies associated with some age/size classes. Therefore, elucidating associations between maternal morphological traits and reproductive investment over the lifespan will contribute to the understanding of the meaning of female phenotypic variability. Lizards have been an interesting model group for studying reproductive strategies from an ecological and evolutionary perspective in recent decades due to their life-history diversity. The aim of this work was to elucidate variations in the reproductive investment of females according to their multivariate morphology in order to understand if the expression of phenotypic variability is accompanied by variability in reproductive strategies of females in Salvator merianae. We found an annual-biennial pattern of reproduction dependent on female phenotype. Fat storage and follicle development were plastic traits that varied with female body size. Moreover, multiple phenotypic traits other than body length were signs of the reproductive value of a female; tail and abdominal perimeter were related to potential clutch mass and clutch size, respectively. Oviductal traits varied among females of different body length and were determinant of clutch size. Mass of total clutch and individual eggs varied independently of the number of offspring and were inversely related to interlimb length. Therefore, the variability found in the different reproductive traits associated to morphological traits indicates that variability in reproductive strategies is related to multivariate maternal phenotype, although the species does not exhibit discrete phenotypic differences.

Las estrategias reproductivas pueden ser caracterizadas de acuerdo a: cuán frecuente y cuándo las hembras se reproducen, cuánto invierten y de qué manera su inversión reproductiva es distribuida en las camadas. La plasticidad de los caracteres puede conducir a cambios en las estrategias reproductivas asociados con las clases de tamaño/edad. Por lo tanto, elucidar las asociaciones entre rasgos morfológicos maternos y la inversión reproductiva a lo largo de la vida contribuirá al entendimiento del significado de la variabilidad fenotípica de las hembras. Los lagartos han sido un interesante grupo modelo para el estudio de las estrategias reproductivas en las décadas recientes, tanto desde una perspectiva ecológica como evolutiva, debido a la diversidad de sus historias de vida. El objetivo de este trabajo fue elucidar variaciones en la inversión reproductiva de las hembras de acuerdo a su morfología multivariada para comprender si la expresión de la variabilidad fenotípica está acompañada de variabilidad en las estrategias reproductivas de hembras de Salvator merianae. Nosotros encontramos un patrón de reproducción anual-bianual dependiente del fenotipo de las hembras. El almacenamiento de grasa y el desarrollo folicular fueron rasgos plásticos que variaron según el tamaño corporal de las hembras. Asimismo, otros rasgos fenotípicos diversos del tamaño corporal fueron señales del valor reproductivo de las hembras; el perímetro de la cola y abdominal estuvieron relacionados a la masa y al tamaño de la camada, respectivamente. Los rasgos oviductales variaron entre hembras con diferente longitud y fueron determinantes del tamaño de camada. La masa total de la camada y de los huevos individuales variaron independientemente del número de crías potenciales y estuvieron inversamente relacionados al largo interaxila de las hembras. Por lo tanto, la variabilidad encontrada en los diferentes caracteres reproductivos, asociada a rasgos a morfológicos, indica que la variabilidad en las estrategias reproductivas está relacionada al fenotipo multivariado materno, aunque la especie no exhiba diferencias fenotípicas discretas.

The ridged treefrog, Dryophytes plicatus, is currently categorized as threatened by the Mexican government. Unfortunately, relatively little is known about the ecology or the conservation threats confronting D. plicatus. Here, we examine how aspects of the terrestrial (proportion of visits with evidence of livestock, distance to nearest trees) and aquatic (proportion of visits with water, dissolved oxygen, total dissolved solids, water temperature, stream width, water depth, bank height, water velocity) habitat affects the distribution of D. plicatus along the Arroyo del Axolotes, a stream in the mountains surrounding Mexico City. The distribution of adult D. plicatus was positively related to the proportion of visits during which a study reach had water. The distribution of larval D. plicatus was negatively related to the proportion of visits with evidence of livestock and water velocity, and positively related to stream width. In conclusion, the extent of current anthropogenic impacts on the distribution of D. plicatus along the Arroyo los Axolotes is currently limited; however, the effects of humans on this relatively unspoiled stream is likely to increase.

The Sierra Nevada de Santa Marta of northern Colombia is home to several endemic species. Here we show that the names of two purported endemic lizard species, Anolis umbrivagus and A. paravertebralis, are junior synonyms of Santa Marta endemic A. solitarius. We present morphological evidence for this inference and photographs of A. solitarius in life.

Individual parasite load depends on several factors such as sex, body size or climatic conditions. In turn, parasites may produce several short- and long-term pathologies. Herein, we analyze the ectoparasite load of the Geckobia mite in two ecologically contrasting populations (north and south of Tenerife) of the gecko Tarentola delalandii. For this purpose, we performed random transects to capture geckos under rocks in each population and counted all mites found on any part of each gecko's body. A generalized linear model showed no significant effect on mite abundance of site, season, sex (within population), condition index, or temperature of the refuges. However, there were significant effects of the interactions between season by condition index and season by sex (nested within population). Parasitism was higher in individuals with lower body index values in autumn–winter than those with higher body condition in spring–summer. Moreover, females of the northern population were more heavily parasitized than males and juveniles in the year's cooler months. We discuss several potential explanations for these results.

Tail bifurcation in lizards is caused by an anomalous regeneration process after tail autotomy. A recent review shows that nearly half of the records came from social media and one of the less represented families was Liolaemidae (one case). The genus Liolaemus is mostly distributed along countries in the southern Andes, which have low numbers of tail bifurcation reports. Is the low incidence of tail bifurcation in Liolaemus a real biological phenomenon, or just a sampling artifact? Due to the lack of targeted searches and the large number of species on this group, we expect that an extensive survey will significantly increase the number of cases. We reviewed the scientific literature, internet sites, and social media (Instagram, Facebook, Flickr, and iNaturalist, 2020) using search terms in Spanish, Portuguese, and English. We found 16 tail bifurcation events corresponding to seven species, including a novel field observation. All bifurcations occur on the distal half of the tail congruently with described trends. Liolaemus tenuis was the most commonly recorded species, which could be explained by its presence in urban and natural areas. The same oversampling bias might affect the geographic distribution of all records. Our field observation might correspond to the first documented re-sight of a lizard with bifurcated tail. With the majority of records from social media, this study exemplifies the relevance of citizen science to document rare events. But, at the same time, it is a warning call for the need of more academic validation of the natural history and museum-based work.

Anurans are anatomically built for jumping, requiring the muscles to contract to generate sufficient mechanical force to launch their bodies. A lot of energy is needed in the hind limbs, where the majority of the force is produced, whereas the front legs and both girdles serve mainly to support the frog's weight at rest as well as to absorb the shock of landing. Different species of anurans have different locomotion mechanisms, evidenced by comparing the mechanical contractile properties of hind limb muscles. In this study, we compared two muscles in arboreal (Agalychnis dacnicolor), terrestrial (Incilius marmoreus), and aquatic (Lithobates sierramadrensis) species of Mexican anurans. We performed low frequency in situ stimulations of the muscles and found that A. dacnicolor showed higher stresses than L. sierramadrensis and I. marmoreus in the two studied muscles, the cruralis and the gastrocnemius. Regarding the cruralis, the stress generated by the aquatic and terrestrial anurans was up to 23% less than that generated by the arboreal anuran. There was also a difference of up to 30% in the ratio of performance between low frequencies and twitch in L. sierramadrensis compared to the other anurans. These differences in muscle physiology suggest adaptive differences among species, although more comprehensive studies are needed to corroborate this hypothesis.

This study aimed to evaluate the status of parasitic infections of colubrid snakes living in serpentariums in northeastern Argentina. Specimens were analyzed through clinical examination and coproparasitological surveys. In cases of death, specimens were necropsied, and histopathological exams were performed to determine its cause(s). Out of 30 specimens examined from 12 different species, parasites were found in 25 of them (83%). Nematodes were most common, with rhabdiasid and ascaridid helminths accounting for 57% and 40% of all infections, respectively. Further, the ascarid Hexametra boddaertii was identified in a specimen of Erythrolamprus aesculapii. Coccidian, digenean, and pentastomid parasites were also found less frequently. We identified the pentastomids Raillietiella furcocerca and Cephalobaena tetrapoda in specimens of Pseudablabes patagoniensis. We revealed systemic lesions induced by endoparasites, including enteritis and detachment of the gut mucosa by ascarids, tissue granulomas by rhabdiasids, and pulmonary microhemorrhages by pentastomids. Additionally, rhabdiasid-induced lesions in Duvernoy's gland were shown for the first time. Regarding ectoparasites, we identified the tick Amblyomma dissimile in a specimen of P. patagoniensis. On the whole, this study provides relevant information about the prevalence and pathophysiological effects of parasites on captive colubrids and paves the way for treatment strategies of such infections.

Information on the use of food resources and habitat are important tools for understanding trophic niche and ecological relationships. Many factors can influence the diet and eating habits of anurans. Species of the genus Proceratophrys are important components of the leaf litter frog communities in the Neotropical forests, including P. ararype, a species with restricted distribution in northeast Brazil. Therefore, we describe aspects of habitat use and evaluate the diet of P. ararype and compare these results with information on other Proceratophrys species. We collected, dissected, and examined the gastrointestinal tracts of 40 individuals, among which 55% contained food items, with 11 prey categories identified. We also tested the relationship between prey item categories and sampling sites, differences between males and females, and the relationship between frog size and prey. The species can be characterized as generalist, and the volume of prey ingested was not related to the average size of the individuals. Additionally, the habitat most used by the anuran was leaf litter; thus, it was inferred that this frog species uses the environment horizontally. The data found and comparisons with the literature suggest that the diet composition of P. ararype is determined by the availability of arthropods in the environment. This study demonstrates the importance of understanding habitat use, highlighting opportunistic behavior, such as the pattern found for anuran amphibians, contributing to elucidate the biology of anurans with relictual distribution, especially in semi-arid regions.