Twelve new, short notes were involving amphibians and reptiles in Texas and South Dakota were published from December 2020–December 2021 in Herpetological Review. Six are single Geographic Distribution Notes, three are far larger collections of distributional records (containing 12, 17, and 31 records), and three are Natural History Notes. All Texas distribution records were from south Texas (e.g., Guadiana et al. 2020) and along the Gulf Coast (e.g., Davis 2021c), while those from South Dakota are from the south-central region (Davis. 2021a). The Natural History Notes include a report of a new diet record for Masticophis flagellum (Robinson and Davis 2020), information of reproductive timing for Kinosternon flavescens (Davis et al. 2021), and information on aquatic escape behavior and time spent submerged by Anolis sagrei (Davis 2021d). 

Conservation concerns are increasing for numerous freshwater turtle species, including Pseudemys gorzugi, which has led to a call for more research. However, traditional sampling methodologies are often time consuming, labor intensive, and invasive, restricting the amount of data that can be collected. Biases of traditional sampling methods can further impair the quality of the data collected, and these shortfalls may discourage their use. The use of unmanned aerial vehicles (UAVs, drones) for conducting wildlife surveys has recently demonstrated the potential to bridge gaps in data collection by offering a less labor intensive, minimally invasive, and more efficient process. Photographs and video can be obtained by camera attachments during a drone flight and analyzed to determine population counts, abundance, and other types of data. In this study we developed a detailed protocol to survey for large, freshwater turtle species in an arid, riverine landscape. This protocol was implemented with a DJI Matrice 600 Pro drone and a SONY ILCE α6000 digital camera to determine P. gorzugi and sympatric turtle species occurrence across 42 sites in southwestern Texas, USA. The use of a large drone and high resolution camera resulted in high identification percentages, demonstrating the potential of drones to survey for large, freshwater turtle species. Numerous advantages to drone-based surveys were identified as well as some challenges, which were addressed with additional refinement of the protocol. Our data highlight the utility of drones for conducting freshwater turtle surveys and provide a guideline to those considering implementing drone-mounted high-resolution cameras as a survey tool.

Bogolin AP, Davis DR, Kline RJ, Rahman AF. 2021. A drone-based survey for large, basking freshwater turtles species. PLoS ONE 16:e0257720. [PDF]

The emergence of a global pandemic due to the spread of COVID-19 has had profound effects on how research and scholarly activities are conducted for many professional herpetologists. Responses to COVID-19 and mitigation efforts vary by country and institution but have largely resulted in the closures of academic campuses and research areas, travel restrictions, and interruptions in research funding. These responses have forced herpetologists to change the way they manage their professional responsibilities.

Davis DR, Allen B. 2020. Effects of the COVID-19 pandemic on herpetologists. World Congress of Herpetology Newsletter 1(2):26–31. [PDF]

Three new, short notes were involving amphibians and reptiles in South Dakota were published in the December 2020 issue of Herpetological Review. The first was the description of two new county records for Wood Frogs (Rana sylvatica) in northeastern South Dakota. Wood Frogs have recently been expanding its range into and along the Prairie Coteau in recent years (see link). These specimens were collected by regional biologists in April 2020 represent two of eight new localities where individuals were seen or heard chorusing in April 2020. The second is a new record of Plains Hog-nosed Snake (Heterodon nasicus) from Gregory County. Though this specimen was collected in 1925, erroneous locality information recorded the individual from nearby in Nebraska, though the snake was actually collected near Fort Randall, along the Missouri River in present day Gregory County, South Dakota. The third is a note reporting an additional, previously unreported predator of the Smooth Greensnake (Opheodrys vernalis), the Wild Turkey, after an adult Smooth Greensnake was discovered in the crop of a Wild Turkey that was harvested in April 2020

Davis DR, Schardin B. 2020. Opheodrys vernalis (Smooth Greensnake). Predation. Herpetological Review 51:874. [PDF]

Davis DR. 2020. Geographic distribution: Heterodon nasicus (Plains Hog-nosed Snake). Herpetological Review 51:780. [PDF]

Davis DR, McElroy OD, Skadsen DR. 2020. Geographic distribution: Rana sylvatica (Wood Frog). Herpetological Review 51:770–771. [PDF]

The diversity of Philippine amphibians and reptiles has increased over the last few decades, in part due to re-evaluation of species formerly believed to be widespread. Many of these investigations of widespread species have uncovered multiple closely related cryptic lineages comprising species complexes, each restricted to individual Pleistocene Aggregate Island Complexes (PAICs). One group in particular for which widespread cryptic diversity has been common is the clade of Philippine skinks of the genus Brachymeles. Recent phylogenetic studies of the formerly recognized widespread species Brachymeles bonitae have indicated that this species is actually a complex distributed across several major PAICs and smaller island groups in the central and northern Philippines, with numerous species that exhibit an array of digit loss and limb reduction patterns. Despite the recent revisions to the B. bonitae species complex, studies suggest that unique cryptic lineages still exist within this group. In this paper, we resurrect the species Brachymeles burksi Taylor 1917, for a lineage of non-pentadactyl, semi-fossorial skink from Mindoro and Marinduque islands. First described in 1917, B. burksi was synonymized with B. bonitae in 1956, and has rarely been reconsidered since. Evaluation of genetic and morphological data (qualitative traits, meristic counts, and mensural measurements), and comparison of recently-obtained specimens to Taylor’s original description support this species’ recognition, as does its insular distribution on isolated islands in the central portions of the archipelago. Morphologically, B. burksi is differentiated from other members of the genus based on a suite of unique phenotypic characteristics, including a small body size, digitless limbs, a high number of presacral vertebrae, the absence of auricular openings, and discrete (non-overlapping) meristic scale counts. The recognition of this central Philippine species further increases the diversity of non-pentadactyl members of the B. bonitae complex, and reinforces the biogeographic uniqueness of the Mindoro faunal region.

Siler CD, Freitas ES, Sheridan JA, Maguire SN*, Davis DR, Watters JL, Wang K, Diesmos AC, Brown RM. 2020. Additions to Philippine slender skinks of the Brachymeles bonitae complex (Reptilia: Squamata: Scincidae) IV: resurrection and redescription of Brachymeles burksi. Philippine Journal of Systematic Biology 14:10.26757/pjsb2020b14005. [PDF]

Historically, only six records of Wood Frogs (Rana sylvatica) existed from South Dakota, all represented by museum specimens from the 1920s. No other Wood Frogs were reported in South Dakota for the next six decades, and the species was presumed extirpated until 1997 when Wood Frog calls were recorded at two sites in northeastern Roberts County. Since 1997, numerous individuals have continued to document Wood Frogs in northeastern Roberts County. It was not until 2016 that Wood Frogs were detected outside of northeastern Roberts County. Here, we report additional records of Wood Frogs from the Prairie Coteau, ca. 50 km southwest of previously known populations.

Skadsen DR, Davis DR. 2020. A population of wood frogs (Rana sylvatica) in southwestern Roberts County and a new county record for Grant County, South Dakota. The Prairie Naturalist 52:31–32. [PDF]

While shell diseases may be often encountered in captive aquatic turtles maintained in less than optimum conditions, cases of nonulcerating shell disease in wild populations are rare. We discovered lesions on the carapace of individual Kinosternon flavescens (Yellow Mud Turtle) adapted to a highly aquatic existence in the artificial ponds of a cattle ranch in the Chihuahuan Desert of west Texas. Because the carapacial lesions seemed to represent a continuum of a single process, we followed the gross changes in the lesions on turtles over a 13-yr period, testing the hypothesis that we were seeing a progressive shell disease. We confirmed our working hypothesis as we observed Arnoldiella chelonum, a common, filamentous alga, protruding from enlarged pores in newly formed shell and growing under translucent shell lamellae. As the disease advanced, our gross and histological studies revealed that algae were found between more of the shell lamellae, eventually culminating with sloughing of lamellae. Erosion of lamellae led to a localized but complete loss of portions of the scute and exposure of underlying bone. We provide data on the occurrence of this condition among the marked population and progression of the lesions to more-severe forms in individual turtles. Studies of specimens in research collections provided evidence of our observed disease process in K. flavescens across time and throughout the distribution of the species in Texas. We suggest that, by capitalizing on permanent artificial water sources, K. flavescens has serendipitously allowed A. chelonum to invade and damage the nonliving portion of the shell.

Christiansen JL, Davis DR, Jacobson ER, LaDuc TJ. 2020. A potential new shell disease process revealed by a long-term field study of the yellow mud turtle, Kinosternon flavescens, in Texas. Journal of Herpetology 54:1–8. [PDF]

Water‐borne hormone measurement is a noninvasive method suitable for amphibians of all sizes that are otherwise difficult to sample. For this method, containment‐water is assayed for hormones released by the animal. Originally developed in fish, the method has expanded to amphibians, but requires additional species‐specific validations. We wanted to determine physiological relevance of water‐borne corticosterone in spotted salamanders (Ambystoma maculatum) by comparing concentrations to those taken using established corticosterone sampling methods, such as plasma. Using a mixture of field and laboratory studies, we compared water‐borne corticosterone levels to other traditional methods of sampling corticosterone for spotted salamander larvae, metamorphs, and adults. Despite multiple attempts, and detecting differences between age groups, we found no correlations between water‐borne and plasma corticosterone levels in any age group. Water‐borne sampling measures a rate of release; whereas plasma is the concentration circulating in the blood. The unique units of measurement may inherently prevent correlations between the two. These two methods may also require different interpretations of the data and the physiological meaning. We also note caveats with the method, including how to account for differences in body size and life history stages. Collectively, our results illustrate the importance of careful validation of water‐borne hormone levels in each species in order to understand its physiological significance.

Millikin AR, Woodley SK, Davis DR, Moore IT, Anderson JT. 2019. Water-borne corticosterone and plasma corticosterone are not correlated in spotted salamanders. Ecology and Evolution 9:13942–13953. [PDF]

Global climate change is negatively impacting global biodiversity and ectothermic vertebrates, with amphibians being the most imperiled vertebrate taxa. Increased mean global atmospheric temperatures, high rates of habitat degradation, and exposure to infectious diseases, such as chytridiomycosis, have contributed to population declines and extinctions of rare and endangered amphibian species. Field-based monitoring of physiological endocrine traits can help determine the sub-lethal effects of environmental stressors and provide early alerts when populations are chronically stressed. Recent advances in amphibian stress endocrinology include the development and use of non-invasive methods to quantify the glucocorticoid, or stress biomarker, corticosterone. Non-invasive methods, such as urinary, skin and buccal swabs, and water-borne hormone monitoring methods (suited for terrestrial and aquatic dwelling species), are available to quantify baseline and short-term physiological stress responses of amphibians under field settings. In this review, we illustrate, by using two case studies of aquatic and terrestrial amphibian species, the applications of non-invasive corticosterone monitoring methods to advance the ecological knowledge and conservation of imperiled amphibian species, discuss the limitations of these methods, and provide future directions for the use of non-invasive hormone monitoring methods. We highlight the use of non-invasive field endocrinology methods to monitor the impacts of environmental stressors on the physiology of amphibians, which can be applied to advance ecological research, conservation, and management of imperiled species.

Narayan EJ, Forsburg ZR, Davis DR, Gabor CR. 2019. Non-invasive methods for measuring and monitoring stress physiology in imperiled amphibians. Frontiers in Ecology and Evolution 7:431. [PDF]