Tropidurus Oreadicus Research Articles

A highly polymorphic South American collared lizard (Tropiduridae: Tropidurus) reveals that open–dry refugia from South-western Amazonia staged allopatric speciation

Abstract Research on Pleistocene Amazonian refugia has predominantly targeted forest-dwelling taxa, although evidence suggests that endemic species have also evolved in peripheral Amazonian enclaves of open–dry habitats. In Rondônia, Brazil, Tropidurus lizards are restricted to savannah relicts that were once connected to the core Cerrado biome. These populations are currently allocated under Tropidurus oreadicus but hypothesized to comprise allopatric species that evolved in response to landscape changes induced by Pleistocene climatic fluctuations. Phylogenetic analyses support the monophyly of populations from savannah enclaves from Rondônia but place them as distantly related to T. oreadicus. We describe these populations as a new species with unprecedented levels of chromatic polymorphism. A pre-Pleistocene origin is inferred for this new taxon, and dating analysis indicates that Tropidurus species endemic to savannah enclaves diverged from relatives distributed in core open–dry biomes in a non-temporally overlapping fashion. Species distribution models estimate vast climatically suitable areas for the new species during the Last Interglacial, followed by significant contraction during the Last Glacial Maximum, and subsequent expansion and northward displacement towards the Holocene and the present. We conclude that landscape transformations played an important role in the evolution of lizards from enclaves, but their speciation history is temporally deeper than previously thought.

Short-term impact of a wildfire on the homeostasis of Tropidurus oreadicus lizards.

Wildfires cause significant changes in natural habitats and can impact lizard populations. Through changes in the thermal environment, reduced prey availability, and increased exposure to parasite vectors, wildfires affect lizard physiology, immunity, and health. We sampled 56 Tropidurus oreadicus lizards from Cerrado savannas of Brazil living in two adjacent sites: one burned 14 days before the study, and the other unburned for 6 years. We logged the air temperatures of those sites throughout fieldwork. We assessed the short-term possible homeostatic imbalances caused by the fires via measuring body mass, circulating levels of corticosterone (CORT), leukocytes profile changes in heterophile-lymphocyte ratios (HLRs), innate immunity using the bacterial killing assay (BKA), and the diagnosis of hemoparasites using molecular techniques. The air temperature was significantly higher in the burned site. There was no difference in lizard body mass between the two sites, suggesting that prey availability was not affected by the wildfire. While parasite presence was seemingly not affected by fire, the timing of initial parasite infection for animals in the study was unknown, so we also evaluated parasitism as an independent variable relative to the other metrics. Our results showed that parasitic infections lead to reduced bactericidal capacity and body mass in lizards, suggesting clinical disease and depletion of innate immune resources. Moreover, we observed increased HLR with fire and parasitic infections and a strong negative correlation with BKA. These findings suggest that the increased environmental temperature following wildfires may lead to increased CORT and decreased BKA.

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.

FGIN-1-27, an agonist at translocator protein 18 kDa (TSPO), produces anti-anxiety and anti-panic effects in non-mammalian models

FGIN-1-27 is an agonist at the translocator protein 18 kDa (TSPO), a cholesterol transporter that is associated with neurosteroidogenesis. This protein has been identified as a peripheral binding site for benzodiazepines; in anamniotes, however, a second TSPO isoform that is absent in amniotes has been implicated in erythropoiesis. Functional conservation of the central benzodiazepine-binding site located in the GABAA receptors has been demonstrated in anamniotes and amniotes alike; however, it was not previously demonstrated for TSPO. The present investigation explored the behavioral effects of FGIN-1-27 on an anxiety test in zebrafish (Danio rerio, Family: Cyprinide) and on a mixed anxiety/panic test on wall lizards (Tropidurus oreadicus, Family: Tropiduridae). Results showed that FGIN-1-27 reduced anxiety-like behavior in the zebrafish light/dark preference test similar to diazepam, but with fewer sedative effects. Similarly, FGIN-1-27 also reduced anxiety- and fear-like behaviors in the defense test battery in wall lizards, again producing fewer sedative-like effects than diazepam; the benzodiazepine was also unable to reduce fear-like behaviors in this species. These results A) underline the functional conservation of TSPO in defensive behavior in anamniotes; B) strengthen the proposal of using anamniote behavior as models in behavioral pharmacology; and C) suggest TSPO/neurosteroidogenesis as a target in treating anxiety disorders.

Domestic, peridomestic and wild hosts in the transmission of Trypanosoma cruzi in the Caatinga area colonised by Triatoma brasiliensis.

The role played by different mammal species in the maintenance of Trypanosoma cruzi is not constant and varies in time and place. This study aimed to characterise the importance of domestic, wild and peridomestic hosts in the transmission of T. cruzi in Tauá, state of Ceará, Caatinga area, Brazil, with an emphasis on those environments colonised by Triatoma brasiliensis. Direct parasitological examinations were performed on insects and mammals, serologic tests were performed on household and outdoor mammals and multiplex polymerase chain reaction was used on wild mammals. Cytochrome b was used as a food source for wild insects. The serum prevalence in dogs was 38% (20/53), while in pigs it was 6% (2/34). The percentages of the most abundantly infected wild animals were as follows: Thrichomys laurentius 74% (83/112) and Kerodon rupestris 10% (11/112). Of the 749 triatomines collected in the household research, 49.3% (369/749) were positive for T. brasiliensis, while 6.8% were infected with T. cruzi (25/369). In captured animals, T. brasiliensis shares a natural environment with T. laurentius, K. rupestris, Didelphis albiventris, Monodelphis domestica, Galea spixii, Wiedomys pyrrhorhinos, Conepatus semistriatus and Mus musculus. In animals identified via their food source, T. brasiliensis shares a natural environment with G. spixii, K. rupestris, Capra hircus, Gallus gallus, Tropidurus oreadicus and Tupinambis merianae. The high prevalence of T. cruzi in household and peridomiciliar animals reinforces the narrow relationship between the enzootic cycle and humans in environments with T. brasiliensis and characterises it as ubiquitous.

Discrimination of anxiety- versus panic-like behavior in the wall lizard Tropidurus oreadicus.

test battery is proposed for wall lizards (Tropidurus oreadicus) that consists of inducing tonic immobility (TI) followed by post-TI behavioral scoring. After the induction of TI, the usual behavioral sequence was flight followed by freezing and tongue-flicking and/or thigmotaxis, with flight being more probable than freezing. These sequences were not observed after restraint in a normal upward position (which induced freezing but not TI) or after handling (which increased the probability of tongue-flicking). Alprazolam and imipramine selectively decreased the duration of TI as well as the following flight and freezing behavior. Tongue-flicking was increased by diazepam and alprazolam, whereas fluoxetine decreased it. Finally, thigmotaxis was reduced by diazepam, alprazolam, and imipramine but increased by fluoxetine. These results suggest that panic and anxiety can be discriminated pharmacologically in wall lizards.

Strongyluris amazonicus n. sp. (Nematoda: Heterakidae): A parasite of Tropidurus oreadicus from the Brazilian Amazon

Tropidurus oreadicus Rodrigues 1987 is a recently described species, thus there are no reports of helminthes parasites for this species. In this study, a morphological characterisation was performed of a nematode species parasite of the large intestine of T. oreadicus captured in an urban area. This urban area is similar to the estuarine dale from Guamá river and the “igarapés” of Belém, Pará State, Brazil. Morphological analysis suggested that the parasite is a new species of nematode, based mainly on the number and distribution pattern of the caudal papillae in males, which is unique for this species. In the present work, we describe for the first time the structure, number, and disposition of the cervical papillae. The morphological data were supported by scanning electron microscopy, which served as an important tool for distinguishing these nematodes from other species of the genus.

Histological evidence of reproductive activity in lizards from the APM Manso, Chapada dos Guimarães, Mato Grosso State, Brazil

The construction of dams causes major impacts on fauna by changing or eliminating irreversibly their habitats. The resulting changes lead to deep potential modifications on reproductive biology and population structure of lizards, snakes and amphisbaenas. The reservoir in the Multiple Use Area of Manso (APM-Manso) is located near to Chapada dos Guimaraes National Park, in Mato Grosso State. We analyzed comparatively the male gonads of Anolis meridionalis, Colobosaura modesta, Cercosaura ocellata, Cnemidophorus ocellifer, Hoplocercus spinosus, Bachia bresslaui, Mabuya frenata, Micrablepharus atticolus and Tropidurus oreadicus, from APM-Manso, aiming to verify possible changes in the reproductive success according to environmental changes. Before the impoundment A. meridionalis, Colobosaura modesta, Cercosaura ocellata, M. atticolus and T. oreadicus showed up reproductive. However, during the impoundment period they presented changes in seminiferous tubules, evidenced by the absence of spermatids and spermatozoids. B. bresslaui and M. frenata had no differences in the seminiferous tubules before and after the impoundment, being reproductive in both moments. The damming and the formation of the lake of Manso reservoir may have interfered on the reproduction of some lizards species, especially if the reproductive cycle is regulated by the rainfall of the habitat.

Helminths from Lizards (Reptilia: Squamata) at the Cerrado of Goiás State, Brazil

Forty-three specimens representing 11 species of lizards (Ameiva ameiva, Anolis chrysolepis brasiliensis, Cnemidophorus cf. parecis, Hemidactylus mabouia, Mabuya dorsivittata, Mabuya nigropunctata, Ophiodes striatus, Philautus acutirostris, Tropidurus itambere, Tropidurus oreadicus, and Tupinambis merianae) collected in 6 localities of the Cerrado biome in the Brazilian state of Goiás were examined for helminths. Thirteen species of nematodes (Cruzia travassosi, Gynaecometra bahiensis, Oswaldofilaria sp., Parapharyngodon sp., Parapharyngodon largitor, Parapharyngodon sceleratus, Pharyngodon travassosi, Physaloptera sp., Physaloptera lutzi, Physaloptera retusa, Physalopteroides venancioi, Subulura lacertilia) and an unidentified species of cestode (Oochoristica sp.) were recovered from lizard hosts. Thirteen new host records and 7 locality records are reported.

Feeding ecology of the lizard Tropidurus oreadicus Rodrigues 1987 (Tropiduridae) at Serra dos Carajás, Pará state, northern Brazil

Tropidurus species commonly prey on arthropods, but they may also feed on vertebrates and plant material. The lizard Tropidurus oreadicus (Tropiduridae) is common in open vegetation habitats and generally has sexual dimorphism. In this study we analyzed the diet of T. oreadicus at Serra dos Carajás, Pará, in the north of Brazil. Snout-vent length (SVL) and jaw width (JW) were taken for 34 lizards. There was a significant difference in SVL and in JW, with males being larger than females. All lizards analyzed contained food in their stomachs. The diet of T. oreadicus at Serra dos Carajás was characterized by the consumption of a relative wide spectrum of food item categories (21 types of items), consisting of arthropods, part of one vertebrate and plant material, which characterizes the diet of a generalist predator. Volumetrically, the most important items in the diet of both sexes of T. oreadicus were flowers (M = 61.7%; F = 33%) and orthopterans (M = 1.7%; F = 3.5%). Ants were the most frequently consumed (100% for both sexes) and the most numerous (M = 94.5%; F = 89.4%) food item. Flowers also were frequently consumed (M = 91.7%; F = 54.5%), with their relative consumption differing significantly between sexes. There was not a significant sexual difference in prey volume, neither in number of preys per stomach, nor in type of prey ingested. There was no relationship between lizard jaw width and the mean volume of prey. The data showed that T. oreadicus is a relatively generalist lizard in terms of diet and that consumes large volumes of plant material, especially flowers of one species of genus Cassia.

História natural de Tropidurus oreadicus em uma área de cerrado rupestre do Brasil Central

Aspectos ecológicos e da biologia reprodutiva de Tropidurus oreadicus foram investigados em uma área de cerrado rupestre do Brasil Central. Foram estudados a morfometria, o uso do microhábitat, o padrão de atividade, a dieta e características da biologia reprodutiva de T. oreadicus em Cocalzinho - GO, de abril a setembro/2003. São animais sexualmente dimórficos, com os machos adultos maiores que as fêmeas. O microhábitat preferencial utilizado pela espécie foi a superfície das rochas (hábito saxícola). A espécie mostrou padrão de atividade unimodal. Foram frequentemente observados parados e expostos ao sol entre 9:00 e 10:59 horas. A alimentação desta população de T. oreadicus é baseada em formigas, larvas de inseto e besouros. Além disso, apresentaram mudanças ontogenéticas e diferenças intersexuais na dieta. Provavelmente essas diferenças estejam associadas à alocação diferenciada dos recursos para o crescimento ou produção dos gametas. A reprodução é provavelmente sazonal ocorrendo principalmente nos meses de maior pluviosidade.

Ecology of isolated open-formation Tropidurus (Reptilia: Tropiduridae) in Amazonian lowland rain forest

Ecological, morphological, and life-history characteristics of three as yet undescribed populations of open-formation Tropidurus species in Rondônia and a population of Tropidurus oreadicus in Pará, Brazil, that are isolated on rock outcrops completely surrounded by lowland tropical forest were compared with similar characteristics of a eurytopic open-formation close relative, Tropidurus hispidus, and a crevice-adapted close relative, Tropidurus semitaeniatus, from an open-formation (caatinga) habitat in northeastern Brazil. Individuals of the isolated Amazonian populations do not enter the forest, but escape into narrow crevices on rock outcrops when disturbed. They are restricted to the only habitat patch in tropical forest similar to open-formation habitats, granitic rock outcrops. The outcrops maintain cerrado and caatinga vegetation and published paleoecological data indicate that the forested area surrounding the outcrops in Rondônia was cerrado in the recent past. Individuals in the isolated Tropidurus populations are morphologically flattened compared with T. hispidis, clutch size is reduced, and relative clutch mass is reduced, as is observed in other crevice-adapted species of lizards. Females deposit eggs under granitic cap rocks, like the flattened lizard T. semitaeniatus. The most parsimonious explanation for the set of characteristics shared by these four isolated lizard populations is that natural selection has led to an adjustment of behavior, morphology, and certain life-history characteristics in response to the high ecological risks associated with entering surrounding forest. It remains unclear whether this occurred once (which assumes a common ancestor), followed by canalizing selection, or the populations converged independently on similar morphology and ecology (which assumes different ancestors). The direction of divergence in behavior, morphology, clutch size, relative clutch mass, and nesting behavior in isolated populations of Tropidurus species remains unknown.

Thermal biology and flight distance ofTropidurus oreadicus(Sauria Iguanidae) in an area of Amazonian Brazil

The thermal biology and flight distance of the tropical lizard Tropidurus oreadicus was studied on iron ore outcrops (called canga) at Serra dos Carajas, in Brazilian Amazonia. Body temperature varied markedly throughout the day (range 32.0 to 38.1 °C), but mean preferred body temperature was 35.8 °C. The air temperature in the microhabitat explained a considerable part of Tropidurus oreadicus body temperature variation, but other factors such as direct insolation and substratum teperature may also be of importance. In the morning, lizards usually climbed onto rocks and assumed progressively changing body orientations and inclinations which increased the interception of sunlight. Later they retreated to vegetation. This suggested that the importance of rocks as basking sites changes during the morning due to the angle of the sun. The flight distance was greater when body temperature was low and this may be of survival value in open areas such as the mineral outcrops of Serra dos Carajas.