Tupinambis Merianae Research Articles

Estimating roadkill rates while accounting for carcass detection and persistence using open-population capture–recapture models

Context Accurately estimating wildlife roadkill is necessary to compare different roads, periods, and species, and to plan and assess mitigation effectiveness. We must account for the two main sources of errors associated with carcass sampling – carcass detection and persistence. Open-population models are used to estimate abundance, survival probabilities, and recruitment in living animal populations, accounting for imperfect detection, and they can be used in the context of animal fatalities. Aims The aim of this study was to explore an open-population approach to estimate comparable roadkill rates from carcass capture–recapture data, accounting for carcass detection and persistence. Methods We surveyed carcasses of the white-eared opossum (Didelphis albiventris) and black-and-white tegu lizard (Salvator merianae) on four road stretches using two sampling designs with different number of visits and sampling sessions. Carcasses were marked to be recaptured over visits within the same sampling session, resulting in a capture history for each carcass. Encounter history data were modelled using the superpopulation formulation of the open-population capture–recapture model under Bayesian inference for different datasets. A daily roadkill rate per kilometre was derived from the model entry probability estimate. Key results We estimated a daily roadkill rate with 1501 captures from 447 opossum carcasses and 511 captures from 218 tegu carcasses. For full data, mean carcass detection over the sessions ranged from 0.49 to 0.85 for the opossum and from 0.27 to 0.80 for the tegu, and mean carcass persistence ranged from 0.60 to 0.94 for the opossum and from 0.64 to 0.91 for the tegu. Scenarios with more occasions and captures increased precision of roadkill rates. Conclusions We were able to explicitly estimate roadkill rates using an open-population capture–recapture model under a Bayesian framework. It provides accurate roadkill numbers for a known time frame and road extension, accounting for imperfect detection and its associated uncertainty. Under scenarios of few carcasses, users should consider a higher number of occasions. Implications Not addressing carcass sampling errors or simplistically addressing them (e.g. only once during the study period) could mislead mitigation efforts. The approach used here can be used to estimate fatalities in other locations, such as windfarms and powerlines, for which repeated observations of marked carcasses are an option.

Open removal models with temporary emigration and population dynamics to inform invasive animal management.

Removal sampling data are the primary source of monitoring information for many populations (e.g., invasive species, fisheries). Population dynamics, temporary emigration, and imperfect detection are common sources of variation in monitoring data and are key parameters for informing management. We developed two open robust‐design removal models for simultaneously modeling population dynamics, temporary emigration, and imperfect detection: a random walk linear trend model (estimable without ancillary information), and a 2‐age class informed population model (InfoPM, closely related to integrated population models) that incorporated prior information for age‐structured vital rates and relative juvenile availability. We applied both models to multiyear, removal trapping time‐series of a large invasive lizard (Argentine black and white tegu, Salvator merianae) in three management areas of South Florida to evaluate the effectiveness of management programs. Although estimates of the two models were similar, the InfoPMs generally returned more precise estimates, partitioned dynamics into births, deaths, net migration, and provided a decision support tool to predict population dynamics under different effort scenarios while accounting for uncertainty. Trends in tegu superpopulation abundance estimates were increasing in two management areas despite generally high removal rates. However, tegu abundance appeared to decline in the Core management area, where trapping density was the highest and immigration the lowest. Finally, comparing abundance predictions of no‐removal scenarios to those estimated in each management area suggested significant population reductions due to management. These results suggest that local tegu population control via systematic trapping may be feasible with high enough trap density and limited immigration; and highlights the value of these trapping programs. We provided the first estimates of tegu abundance, capture probabilities, and population dynamics, which is critical for effective management. Furthermore, our models are applicable to a wide range of monitoring programs (e.g., carcass recovery or removal point‐counts).

Effect of environmental enrichment on Salvator merianae (Squamata: Teiidae) under captivity conditions.

Environmental enrichment seeks to improve the quality of care for animals in captivity through the constant generation of new sources of stimuli to simulate a complexand changing environment. Salvator merianae is a species of large lizard whose native distribution covers the subtropical and humid zones of southeastern South America.The study was carried out in the Experimental Lizard Hatchery belonging to the Facultad de Agronomía y Zootecnia from Universidad Nacional de Tucumán, UNT for its initials in Spanish. Two pens were used, a control group R1 (Enclosure 1) and an experimental group R2 (Enclosure 2), where data were taken ithout enrichment (R2 W/O-E) and with enrichment (R2 WE). An ethogram was used to record the different behaviors that were then grouped into eight categories to evaluate how animals spend their time. Behaviors were recorded on video, the applied technique was the focal animal sampling with instantaneous recording, the extracted data were ex-ported into individual spreadsheets. The Landau index was calculated to determine the existence of hierarchies. The data suggest that the modification of the enclosure conditions has the capacity to alter the behavioral profiles. Only a few behavioral categories showed significant differences. No significant differences were found, in the frequency of the behavioral categories, between males and females. There was a decrease in the frequency of reproductive behavior in males in R2. There was anon-linear hierarchy among the individuals. A ecrease in the chases was observedamong individuals in R2.

Apatite in Hamipterus tianshanensis eggshell: advances in understanding the structure of pterosaur eggs by Raman spectroscopy

Pterosaur eggs can offer information about pterosaur reproductive strategies and are extremely precious because only a small number of specimens have been discovered. Previous studies have mainly focused on morphological descriptions of pterosaur eggs and their embryos while the chemical composition of pterosaur eggs has received little attention. The conventional view believed that the eggshell was composed of calcite. However, previous SEM–EDS results for Hamipterus tianshanensis showed that the eggshell contains phosphorus. Therefore, the object of this research is to determine the mineral composition of the eggshell of H. tianshanensis. Two eggs were analyzed by scanning electron microscopy coupled with energy dispersive X-ray spectrometry (SEM–EDS) and Raman spectroscopy. The SEM–EDS results show that both surface and cross section are porous and characterized by small irregularly shaped particulates. Moreover, the distribution of Ca and P has a strict coincidence in the cross-section of eggshells. Furthermore, neither the intense peaks of calcite nor organic peaks can be observed by Raman spectroscopy in eggshells. Meanwhile, the Raman spectroscopy mapping analysis result shows a sharp and intense peak at approximately 966 cm−1 among the white eggshell, which can be hard evidence that H. tianshanensis eggs are mainly composed of calcium phosphate. Combined with the present of F in the eggshell, it can be inferred that fluorapatite Ca5(PO4)3F is the main mineral. The fluorapatite eggshell can be interpreted in two ways. One explanation is that H. tianshanensis laid apatite-shelled eggs, similar to living Salvator merianae, and the bioapatite transformed to fluorapatite over geological time. Another possible explanation is that the fluorapatite comes from the result of phosphatization of soft egg membrane tissues through taphonomic processes, indicating that H. tianshanensis might have laid soft eggs. Regardless, the results show that fluorapatite, rather than calcite is the main preserved mineral composition of H. tianshanensis eggshell, correcting the previous view. This study contributes to the present understanding of the mineral composition of pterosaur eggshells and may offer some insight into the pterosaur reproduction pattern.

Sevoflurane Sparing Effect of Morphine in Tegus (Salvator merianae) – A Preliminary Study

This study aimed to determine the minimum anesthetic concentration (MAC) of sevoflurane in tegus (Salvator merianae) and the morphine-sparing effect on this variable. In a prospective, non-blinded, crossover study, MAC was first determined in 6 tegus under sevoflurane anesthesia alone (MACSEVO) and then following intramuscular administration of morphine (10 mg/kg), administered 3 hour before sevoflurane anesthesia (MACSEVO+MOR). A standard bracketing technique was applied to determine the MAC by an electrical supramaximal noxious stimulus (50 Hz, 30 mA) delivered at the base of the tail of the tegus. The end-tidal sevoflurane fraction was reduced or increased by 10% in any evidence of negative or positive motor responses, respectively. The MAC was calculated as the mean of the 2 highest successive sevoflurane concentrations that permitted positive responses and the 2 lowest that prevented positive responses. Heart rate, esophageal temperature, and noninvasive mean arterial blood pressure were assessed every 10 minutes. The MAC was significantly different between MACSEVO (2.41 ± 0.06%) and MACSEVO+MORF (1.88 ± 0.43%) (P = .007), with a mean ± SD morphine-induced reduction in the sevoflurane MAC of 22 ± 18% (P = .0158). Heart rate, mean arterial blood pressure, and esophageal temperature did not differ between groups or within groups over time. Results showed that intramuscular premedication with 10 mg/kg morphine produced a sevoflurane sparing effect in tegus with no significant impact on cardiovascular variables.

Chemical characterization and potential use of reptile fat from sustainable programs

Reptile meats and fats are used for their medicinal properties and nutritional values ​​perceived through the culture of native peoples, though often with no scientific basis. Providing scientific information about potential medicinal and nutritional use of reptile fats would be a strategy for the full use of wild animals, supporting the sustainable use and conservation of biodiversity. The objective of this study was to characterize and chemically compare the fat and oil of individuals of Argentine Black and white tegu (Salvator merianae) and Broad-snouted caiman (Caiman latirostris) from sustainable use and conservation programs. In addition, we evaluated the microbiological characteristics and the antimicrobial activity of the oils obtained by different methods. We used two methodologies to obtain oils, one by fusion extraction and the other by drying-decantation (traditional hunter's method). We obtained the chemical and microbiological characterization of fat and oil of latirostris and S. merianae. All the oil samples presented less than 10 CFU/ml of all the microorganisms tested. C. latirostris and S. merianae oil showed nutritional quality parameters that indicate its potential use. Furthermore, S. merianae oil showed antimicrobial activity against Staphylococcus aureus and Candidas tropicalis. No inhibition occurs for the rest of the microorganisms analyzed. C. latirostris oil did not show antimicrobial activity, although the lipid profile does indicate some anti-inflammatory potential. This study demonstrates the potential application of the tested oils and confirms the pharmacological basis for the traditional therapeutic use of S. merianae oil.

Breeding Biology of the Endangered Burrow-Nesting Lesser Crescent-Chested Puffbird Malacoptila minor

For many birds breeding success may be related to the availability of nesting sites, particularly in ecologically specialized cavity-nesting birds. For burrow-nesting species, the selection of an appropriate substrate may be fundamental to a successful breeding attempt. The Lesser Crescent-chested Puffbird Malacoptila minor is a bucconid with a restricted distribution, which is found in the states of Maranhão and Piauí, in northeastern Brazil. It is the only bucconid listed as threatened with extinction, and little is known about its natural history. A total of 49 nests were found over three breeding seasons (2017–2020). Nests consist of burrows dug in the ground that are used only once for breeding. Incubation lasted 21.2 ± 1.3 days and the nestlings fledged after 19.5 ± 2.9 days. The nests contained two or three eggs. The mean hatching rate was 0.46 ± 0.47 eggs per nest and the fecundity rate was 1.0 fledgling per female. The production was 0.53 fledglings per nest, apparent reproductive success was 22.4% (N = 49), and was 15.7% (N = 49) when based on Mayfield's protocol. The probability of breeding success per period was greater during the incubation phase than during the nestling phase. Predation was identified as the principal cause of nest failure (77.5%), mainly during the incubation phase. Three predators were identified: the Crab-eating Fox Cerdocyon thous, the fire ant Solenopsis saevissima, and a lizard, the Common Tegu Salvator merianae. Breeding season starts with the onset of rainy season and nest flooding did not appear to be a concern, which contrasts with the available data on other bucconids. The results of the present study are the first data on the breeding biology of the Lesser Crescent-chested Puffbird, and represent an important advance in the understanding of breeding patterns in the Bucconidae.

Dyadic Movement in an Adult Male and Female Argentine Black and White Tegu (Salvator merianae) in South Florida

Reptiles exhibit a wide diversity of social systems, and while not very common, exclusive and consensual mating relationships have been documented in several lizard species including lizards from the Teiidae family. Here, we document dyadic movement behavior between an adult male and female Salvator merianae (Argentine Black and White Tegu), a large, omnivorous lizard native to Brazil, Uruguay, eastern Paraguay, and Argentina that became established as an invasive species in Florida, in the southeastern United States. Using global positioning system and very high frequency telemetry data, we documented 8–9 days of joint movement between a reproductively active male and female Tegu in Miami-Dade County, FL.

Micromorphological study of the upper digestive tract of the Argentine tegu (Salvator merianae).

Argentine black and white tegus (Salvator merianae) are omnivorous lizards native to southeastern Brazil, Uruguay, eastern Paraguay and northern Argentina, and are invasive species in Florida and Georgia, USA. They are opportunistic feeders, which is what allow them to have such a diverse variety of foods. Tegus raised a particular concern due to their adaptive capability to different environments. Our goal was to provide a micromorphology baseline of oesophagus and stomach and correlate findings with their dietary and invasive capabilities. Four Argentine black and white tegus were used for this study. We collected and processed specimens from oesophagus and stomach using standard histological techniques and stained tissue sections using Haematoxylin and Eosin (H&E), Periodic Acid Schiff (PAS), Alcian Blue (AB) and Verhoef's elastic stains. The oesophagus was lined with ciliated pseudostratified columnar epithelium (PSCE) with goblet cells. Gut-associated lymphoid tissues (GALT) were present occasionally in the oesophagus and more frequently in the stomach. Tunica muscularis (Tm) of the oesophageal-gastric junction had distinct smooth muscle which could function as a sphincter. The mucosa of the stomach was lined with simple columnar epithelium (SC). The glands had neck and dark oxyntico-peptic cells. The pyloric sphincter had more GALT and mucus cells than other regions. The Tm outer layer is thinner than the inner. Presence of large number of goblet cells would support faster transit of the bolus. The short digestive tract and the histological features observed are consistent with the ability of tegus consumption of large amount of food.

Whole-limb scaling of muscle mass and force-generating capacity in amniotes.

Skeletal muscle mass, architecture and force-generating capacity are well known to scale with body size in animals, both throughout ontogeny and across species. Investigations of limb muscle scaling in terrestrial amniotes typically focus on individual muscles within select clades, but here this question was examined at the level of the whole limb across amniotes generally. In particular, the present study explored how muscle mass, force-generating capacity (measured by physiological cross-sectional area) and internal architecture (fascicle length) scales in the fore- and hindlimbs of extant mammals, non-avian saurians (‘reptiles’) and bipeds (birds and humans). Sixty species spanning almost five orders of magnitude in body mass were investigated, comprising previously published architectural data and new data obtained via dissections of the opossum Didelphis virginiana and the tegu lizard Salvator merianae. Phylogenetic generalized least squares was used to determine allometric scaling slopes (exponents) and intercepts, to assess whether patterns previously reported for individual muscles or functional groups were retained at the level of the whole limb, and to test whether mammals, reptiles and bipeds followed different allometric trajectories. In general, patterns of scaling observed in individual muscles were also observed in the whole limb. Reptiles generally have proportionately lower muscle mass and force-generating capacity compared to mammals, especially at larger body size, and bipeds exhibit strong to extreme positive allometry in the distal hindlimb. Remarkably, when muscle mass was accounted for in analyses of muscle force-generating capacity, reptiles, mammals and bipeds almost ubiquitously followed a single common scaling pattern, implying that differences in whole-limb force-generating capacity are principally driven by differences in muscle mass, not internal architecture. In addition to providing a novel perspective on skeletal muscle allometry in animals, the new dataset assembled was used to generate pan-amniote statistical relationships that can be used to predict muscle mass or force-generating capacity in extinct amniotes, helping to inform future reconstructions of musculoskeletal function in the fossil record.

Metabolic and Hormonal Changes Associated with Vitellogenesis in Salvator merianae Lizards.

Vitellogenesis in oviparous vertebrates is a critical marker of the restart of seasonal reproductive activity. During this process of multihormonal regulation, females allocate a considerable amount of organic and mineral reserves to the synthesis of yolk, with changes in their plasma values. In this work, we determined plasma levels of various metabolites and steroid hormones throughout the reproductive cycle in females of Salvator merianae who developed vitellogenic and non-vitellogenic follicular cycles. We worked for two consecutive years with 20 adult females from the Experimental Hatchery of the Facultad de Agronomía y Zootecnia of the Universidad Nacional de Tucumán. Values of metabolites: glucose, triglycerides, cholesterol, calcium, phosphorus, albumin, total proteins, and hormones: estradiol, progesterone, and testosterone, were determined during the following stages of the annual cycle: hibernation, hibernation emergence, courtship-mating, oviposition, and incubation. Vitellogenic females showed significantly higher plasma levels of triglycerides, calcium, phosphorus, and albumin than non-vitellogenic females, mainly in the courtship-mating stage (advanced vitellogenesis). In contrast, annual cholesterol averages were lower in vitellogenic females. Glucose showed changes throughout the annual cycle regardless of the vitellogenic condition. Total proteins plasma levels had very few fluctuations during the cycle. Among the hormones studied, only testosterone showed differences related to vitellogenic condition, with higher levels in non-vitellogenic females during the entire reproductive cycle. The knowledge of these changes associated with vitellogenesis will improve zootechnical management and will allow optimizing the reproductive efficiency of Salvator lizards in captivity.

Thermal stability of an adaptable, invasive ectotherm: Argentine giant tegus in the Greater Everglades ecosystem, USA

AbstractInvasive species globally threaten biodiversity and economies, but the ecophysiological mechanisms underlying their success are often understudied. For those alien species that also exhibit high phenotypic plasticity, such as habitat generalists, adaptations in response to environmental pressures can take place relatively quickly. The Argentine giant tegu (Salvator merianae; tegu) is a large omnivorous lizard from South America that is prolific, long‐lived, vagile, and highly adaptable to disturbed environments. They are well suited to the climate of southeastern United States, introduced to several disjunct areas, including the Everglades, where their voracious appetite threatens native wildlife. Tegus undergo winter dormancy (hibernation) to cope with colder temperatures, and while this behavior may facilitate invasion into more temperate regions, it may also present management opportunities. We studied the thermal habits of wild S. merianae within their invaded range in southern Florida, USA. We used radiotelemetry and trail cameras to verify aboveground behaviors, and temperature dataloggers to monitor surface (sun‐exposed [Te] and shaded [Ts]), ambient (Ta), subsurface ground (Th), and internal body (Tb) temperatures of a population of free‐ranging tegus over several seasons. We evaluated thermal and behavioral data and identified five biologically significant periods: pre‐hibernal, hibernal, cold snaps, hibernal‐basking, and post‐hibernal. We found tegus maintained thermal stability throughout the hibernal period, frequently at temperatures above available thermal microhabitats. Variation in Tb was lowest during hibernation and cold snaps and was less variable than subsurface temperatures despite not leaving their hibernaculum. Hibernal ingress and egress were best predicted by temperature differentials between exposed soil and ambient daily mean temperatures (Te − Ta) and daylength. Though we detected no sex differences, larger animals started hibernation sooner, stayed in hibernation longer, and retained higher fat stores over the study period. One individual did not hibernate, representing only the second record of this behavior. Despite limitations of these descriptive data, this is the first study finely detailing Tb of a population of wild, free‐ranging S. merianae over multiple biologically significant time periods and to associate Tb with thermal habitats within its invasive range. Tegus' apparent ability for thermal stability expands the adaptability breadth of this species and underscores the invasion threat.

Ozonized water used as complementary therapy for stomatitis in Salvator merianae – case report

The Argentine black and white tegu (Salvator merianae) is a reptile belonging to the family Teiidae. Compared with other families, teiids are morphologically similar. However, their sizes vary considerably, with S. merianae being the largest endemic lizard in South America. The characteristics, habitat, and habits of S. merianae need to be investigated, to provide adequate ex situ adaptation opportunities and avoid accidents in the pet industry. One advancing complementary therapy is the use of ozone, which has potent antimicrobial action when applied topically, due to the oxidizing and healing effects resulting from the stimulation of tissue cell proliferation and remodeling. To generate information concerning ozone therapy, the treatment of stomatitis caused by Portland cement in an Argentine black and white tegu using ozonized water as a complementary therapy is reported. Fluid and antibiotic therapies (enrofloxacin, butorphanol, meloxicam, and sucralfate) were introduced, along with the daily rinsing of the oral cavity with freshly prepared ozonized water. No toxic effects relating to ozone use were observed, and its topical use as a complementary therapy proved to be low cost and highly efficient. These findings demonstrate the need to obtain knowledge concerning this therapy and promote its use in wild animals.

Seasonal changes in steroid and thyroid hormone content in shed skins of the tegu lizard Salvator merianae.

Sampling blood for endocrine analysis from some species may not be practical or ethical. Quantification of hormones extracted from nontypical sample types, such as keratinized tissues, offers a less invasive alternative to the traditional collection and analysis of blood. Here, we aimed to validate assays by using parallelism and accuracy tests for quantification of testosterone, corticosterone, progesterone, and triiodothyronine (T3) in shed skins of tegu lizards. We assessed whether hormone content of sheds varied across one year similar to what was previously detected in plasma samples. In addition, we aimed to identify the phase relationship between hormone levels of shed skin and plasma levels obtained from the same animals. High frequency of shedding occurred during the active season for tegus (spring/summer), while shedding ceased during hibernation (winter). All hormones measured in shed skins exhibited seasonal changes in concentration. Levels of testosterone in shed skins of male tegus correlated positively with plasma testosterone levels, while corticosterone in both males and females exhibited an inverse relationship between sample types for the same month of collection. An inverse relationship was found when accounting for a lag time of 3 and 4months between sheds and plasma testosterone. These results indicate that endocrine content of sheds may be confounded by factors (i.e., seasons, environmental temperature, thermoregulatory behavior, among others) that affect frequency of molting, skin blood perfusion, and therefore hormone transfer from the bloodstream and deposition in sheds of squamates.

Diet of the Invasive Argentine Black and White Tegu in Central Florida

Salvator merianae (Argentine Black and White Tegu, hereafter also ABWT) is a large bodied, omnivorous lizard native to South America. In Florida, where the species was introduced via the pet trade and is invasive, there are at least 3 established populations as well as numerous one-off observations. We collected ABWTs from public and private property to determine their diet in central Florida (Hillsborough County) from 2012 to 2016. We determined frequency of occurrence (FO) for items identified to various taxonomic levels, calculated niche overlap to check for an ontogenetic shift in diet, and evaluated seasonal variation in diet. Stomach contents revealed ABWTs (n = 93) in central Florida consume fruit, invertebrates, and vertebrates, including hatchling Gopherus polyphemus (Gopher Tortoise). Frequency of occurrence of food items varied seasonally. Vertebrate prey was most common in the spring, whereas invertebrates and plants were consumed most frequently in summer. Diets among ABWTs were very similar, as indicated by Pianka's measure of niche overlap, regardless of age or sex. A greater proportion of ABWTs in central Florida consumed vertebrates compared to other invasive and native populations (FOcentralFL = 81%, FOsouthernFL= 37%, FOBrazil = 27%, FOArgentina = 44%). Argentice Black and White Tegus in central Florida are generalist omnivores and consume a diversity of taxa across several trophic levels, including imperiled species.

Who Rules Over Immunology? Seasonal Variation in Body Temperature, Steroid Hormones, and Immune Variables in a Tegu Lizard.

Multiple factors can influence the immune response of ectothermic vertebrates, including body temperature (Tb), gonadal steroids, and seasonality, in ways that are thought to reflect trade-offs between energetic investment in immunity versus reproduction. Hibernating tegu lizards (Salvator merianae) are a unique model to investigate how immunocompetence might be influenced by different factors during their annual cycle. We assessed immunological measures (plasma bacterial killing ability, total and differential leukocyte count), plasma hormone levels (testosterone in males, estradiol and progesterone in females, and corticosterone [CORT] in both sexes), Tb, and body condition from adult tegus during each stage of their annual cycle: reproduction, post-reproduction/preparation for hibernation, and hibernation. Our hypothesis that immune traits present higher values during the reproductive phase, and a sharp decrease during hibernation, was partially supported. Immune variables did not change between life history stages, except for total number of leukocytes, which was higher at the beginning of the reproductive season (September) in both males and females. Average Tb of the week prior to sampling was positively correlated with number of eosinophils, basophils, monocytes, and azurophils, corroborating other studies showing that when animals maintain a high Tb, there is an increase in immune activity. Surprisingly, no clear relationship between immune traits and gonadal steroids or CORT levels was observed, even when including life history stage in the model. When gonadal hormones peaked in males and females, heterophil: lymphocyte ratio (which often elevates during physiological stress) also increased. Additionally, we did not observe any trade-off between reproduction and immunity traits, sex differences in immune traits, or a correlation between body condition and immune response. Our results suggest that variation in patterns of immune response and correlations with body condition and hormone secretion across the year can depend upon the specific hormone and immune trait, and that experienced Tb is an important variable determining immune response in ectotherms.

Investigation of keratinase digestion to improve steroid hormone extraction from diverse keratinous tissues

Monitoring the physiology of wild populations presents many technical challenges. Blood samples, long the gold standard of wildlife endocrinology studies, cannot always be obtained. The validation and use of non-plasma samples to obtain hormone data have greatly improved access to more integrated information about an organism’s physiological state. Keratinous tissues like skin, hair, nails, feathers, or baleen store steroid hormones in physiologically relevant concentrations, are stable across decades, and can be used to retrospectively infer physiological state at prior points in time. Most protocols for steroid extraction employ physical pulverization or cutting of the sample, followed by mixing with a solvent. Such methods do produce repeatable and useful data, but low hormone yield and detectability issues can complicate research on small or rare samples. We investigated the use of keratinase, an enzyme that breaks down keratin, to improve the extraction and yield of corticosterone from vertebrate keratin tissues. Corticosterone content of keratinase-digested extracts were compared to non-keratinase extracts for baleen from three species of whale (blue, Balaenoptera musculus; bowhead, Balaena mysticetus; southern right, SRW; Eubalaena australis), shed skin from two reptiles (tegu lizard, Salvator merianae; narrow-headed garter snake, Thamnophis rufipunctatus), hair from arctic ground squirrel (AGS; Urocitellus parryii), feathers from Purple Martins (PUMA; Progne subis), and spines from the short-beaked echidna (Tachyglossus aculeatus). We tested four starting masses (10, 25, 50, 100 mg) for each sample; digestion was most complete in the 10 and 25 mg samples. A corticosterone enzyme immunoassay (EIA) was validated for all keratinase-digested extracts. In all sample types except shed skin from reptiles, keratinase digestion improved hormone yield, with PUMA feathers and blue whale baleen having the greatest increase in apparent corticosterone content (100% and 66% more hormone, respectively). The reptilian shed skin samples did not benefit from keratinase digestion, actually yielding less hormone than controls. With further optimization and refinement, keratinase digestion could greatly improve yield of steroid hormones from various wildlife epidermal tissue types, allowing more efficient use of samples and ultimately improving understanding of the endocrine physiology of wild populations.

Using Enclosed Y-Mazes to Assess Chemosensory Behavior in Reptiles.

Reptiles utilize a variety of environmental cues to inform and drive animal behavior such as chemical scent trails produced by food or conspecifics. Decrypting the scent-trailing behavior of vertebrates, particularly invasive species, enables the discovery of cues that induce exploratory behavior and can aid in the development of valuable basic and applied biological tools. However, pinpointing behaviors dominantly driven by chemical cues versus other competing environmental cues can be challenging. Y-mazes are common tools used in animal behavior research that allow quantification of vertebrate chemosensory behavior across a range of taxa. By reducing external stimuli, Y-mazes remove confounding factors and present focal animals with a binary choice. In our Y-maze studies, a scenting animal is restricted to one arm of the maze to leave a scent trail and is removed once scent-laying parameters have been met. Then, depending on the trial type, either the focal animal is allowed into the maze, or a competing scent trail is created. The result is a record of the focal animal's choice and behavior while discriminating between the chemical cues presented. Here, two Y-maze apparatuses tailored to different invasive reptile species: Argentine black and white tegu lizards (Salvator merianae) and Burmese pythons (Python bivittatus) are described, outlining the operation and cleaning of these Y-mazes. Further, the variety of data produced, experimental drawbacks and solutions, and suggested data analysis frameworks have been summarized.

Functional morphology of the tongue of lizard Salvator merianae (Reptilia: Squamata)

The reptilian tongue has morphological and functional variations according to the feeding mechanisms and habitat of the species. This study aimed to understand the morphofunctional characteristics of the tongue of the lizard Salvator merianae , through anatomical, histological and scanning electron microscopy analyses. This experiment used five adult animals, which were collected in the municipality of Vicosa, Minas Gerais, from Brasil. The tongue of S. merianae was protractile and bifid, important to detect odors and locate prey, strongly muscular and with keratinized and pigmented stratified epithelium for protection. Mucous secretion was present as an important tool for lubrication and protection in view of the protrability of the tongue and the great presence of bacteria. Morphological specificities of the S. merianae tongue reflect its direct participation in feeding, with squamiform papillae for food apprehension. Taste buds were not found, which excludes the tongue participation in the taste.

Argentine Black and White Tegu (Salvator merianae) can survive the winter under semi-natural conditions well beyond their current invasive range

The Argentine Black and White Tegu (Salvator merianae, formerly Tupinambis merianae) is a large lizard from South America. Now established and invasive in southern Florida, and it poses threats to populations of many native species. Models suggest much of the southern United States may contain suitable temperature regimes for this species, yet there is considerable uncertainty regarding either the potential for range expansion northward out of tropical and subtropical zones or the potential for the species establishing elsewhere following additional independent introductions. We evaluated survival, body temperature, duration and timing of winter dormancy, and health of wild-caught tegus from southern Florida held in semi-natural enclosures for over a year in Auburn, Alabama (> 900 km northwest of capture location). Nine of twelve lizards emerged from winter dormancy and seven survived the greater-than-one-year duration of the study. Average length of dormancy (176 d) was greater than that reported in the native range or for invasive populations in southern Florida and females remained dormant longer than males. Tegus grew rapidly throughout the study and the presence of sperm in the testes of males and previtellogenic or early vitellogenic follicles in female ovaries at the end of our study suggest the animals would have been capable of reproduction the following spring. The survival and overall health of the majority of adult tegus in our study suggests weather and climate patterns are unlikely to prevent survival following introduction in many areas of the United States far from their current invasive range.