A NewTropidurus(Tropiduridae) from the Semiarid Brazilian Caatinga: Evidence for Conflicting Signal between Mitochondrial and Nuclear Loci Affecting the Phylogenetic Reconstruction of South American Collared Lizards

A guide to incubate eggs of Tropidurus lizards under laboratory conditions

Studies in Evo-Devo benefit from the use of a variety of organisms, as comparative approaches provide a better understanding of Biodiversity and Evolution. Standardized protocols to incubate eggs and manipulate embryo development enable postulation of additional species as suitable biological systems for research in the field. In the past decades, vertebrate lineages such as Squamata (lizards, snakes, and amphisbaenians) emerged as crucial study systems for addressing topics as diverse as phenotypic evolution and climate change. However, protocols for maintaining gravid females and incubating eggs in the lab under experimental conditions are available to only a few squamate species. This resource article presents a simple incubation guide that standardizes conditions to maintain embryos of Tropidurus catalanensis (Squamata: Tropiduridae) under different experimental conditions, manipulating relevant environmental factors like temperature and humidity. We identified associated effects relating the egg incubation condition to developmental stage, incubation time, hatching success, and resulting morphotypes. Temperature and humidity play a key role in development and require attention when establishing the experimental design. Current literature comprises information for Tropidurus lizards that ponders how general in Squamata are the ecomorphs originally described for Anolis. Studies evaluating phenotypic effects of developmental environments suggest plasticity in some of the traits that characterize the ecomorphological associations described for this family. We expect that this incubation guide encourages future studies using Tropidurus lizards to address Evo-Devo questions.

A novel epidermal gland type in lizards (α-gland): structural organization, histochemistry, protein profile and phylogenetic origins

Chemical signalling is an essential component of the communication system of lizards, and epidermal glands are responsible for producing semiochemicals that regulate many behavioural interactions. Two types of epidermal glands have been previously described for lizards: follicular and generation glands. Generation glands are characterized by the aggregation of novel glandular cell types in the epithelium and the lack of a lumen or external pore. Despite the fact that several subtypes of generation glands have been recognized over the years, the morphology, taxonomic distribution, function and evolutionary origins of generation glands remain nearly unexplored in Neotropical clades. Here, we describe a novel escutcheon-type generation gland (‘α-gland’) for lizards of the South American family Tropiduridae, characterize its structural and ultrastructural organization, and study the homology of the constituent parts in a phylogenetic framework. The α-glands emerged in the ancestor of Eurolophosaurus, Plica, Strobilurus, Tropidurus and Uracentron, and are found in at least 39 species with diverse ecological habits. We preliminarily analysed the protein profile of α-glands and discovered differential expression of protein components between sexes. Our investigations change the general view about epidermal gland homology, leading us to argue that generation and follicular glands are possibly more closely related functionally and evolutionarily than previously thought.

Metropolitan lizards? Urbanization gradient and the density of lagartixas (Tropidurus hispidus) in a tropical city

Urbanization, with its cohort of environmental stressors, has a dramatic effect on wildlife, causing loss of biodiversity and decline in population abundance customarily associated with increasing levels of impervious surface and fragmentation of native habitats. Some studies suggest that faunal species from open habitats, and with higher abundance in natural environments, seem more likely to tolerate and live in urban environments. Here I evaluate how the level of urbanization affects lagartixas (Tropidurus hispidus) one of the most common lizards found in open vegetation ecosystems in NE Brazil. I surveyed a total of 47 transects across sites that differed in proportion of impervious surface (high, mild, peri-urban, and rural). I also collected specific biotic (herbaceous cover, tree, and arthropod abundance) and abiotic (amount of shelters and impervious surfaces) factors that could affect lagartixas abundance. Ants were the most common arthropod both in the rural and urban environment. Lagartixas thrive in urban environments, and trees and shelter were key predictors of their abundance. Lagartixas show a clear association with use of artificial structures. The low densities of lagartixas in rural areas and higher density in urbanized areas suggest that they colonized urban areas due to the hard surfaces and they probably are not exploiting a novel habitat, but somewhat responding to conditions resembling those in which they evolved. Finally, lagartixas are extremely common in tropical cities, they have a suite of features that are associated with selective pressures in cities and they might play a key functional role in urban ecosystems making this lizard an excellent system for the study of ecology and adaptation to the urban environments.

Follicular Development and Reproductive Characteristics in Four Species of Brazilian Tropidurus Lizards

The follicular development and reproductive characteristics of four species of oviparous lizards in the Tropidurus torquatus group were anatomically and histologically evaluated. We measured specimens, recorded the number of follicles and eggs, and removed the right ovary of each individual, which we processed according to histological routine and photo-documented. For all species, ovaries were divided into a cortical germinal bed, where oogonia and stage I oocytes are located, and a medullar stroma, where the remaining follicular developmental stages occur. Microscopic analysis did not show differences in ovarian follicle development for the four species of the T. torquatus group. The only measurement that presented significant variation throughout follicular development was the thickness of the granulosa layer in stage VII follicles. Regarding snout-tovent length at sexual maturity, few variations were observed among the species, with the smallest length recorded for T. oreadicus. Clutch size was higher for T. itambere and T. torquatus species, with a maximum of five and six eggs in the oviducts, respectively. Tropidurus oreadicus and T. hispidus had a maximum of five and six follicles, respectively, but neither species presented eggs in the oviducts. In addition, the reproductive activity varied among the four lizard species of the T. torquatus group. Finally, besides the morphological characteristics observed among these species, this is the first study to report data on the germinal bed, number of ovarian follicles, corpus luteum, and follicular atresia in relation to reproductive activity.