Texas Tortoises (Gopherus berlandieri) are understudied compared to federally protected congeners. Despite important early studies on the basic ecology of G. berlandieri, quantitative identification of habitat associations with specific environmental conditions has been limited. Gopherus berlandieri inhabits Tamaulipan thornscrub across its range, and coastal populations are historically associated with low-relief clay ridges with thick mesquital scrub surrounded by salt prairie grasslands. Our study examined tortoise home range size and association with canopy cover and potential ground moisture at a protected natural area in Cameron County, TX, USA. Twelve tortoises were outfitted with GPS loggers that recorded location once an hour from March 2020 to March 2022. To delineate home ranges, we estimated utilization distributions (UDs) for tortoises as autocorrelated kernel density estimates (AKDEs) at low-use (95%) and core-use (50%) levels for each tortoise. UDs were estimated for the entire study period and during seasons of sustained heat or cold to determine if tortoises used space differently across these seasons over the study period. Applying a use-availability study design, we compared canopy cover and potential mesic ground condition (i.e., precipitation flow accumulation) within each tortoise’s UD (‘‘use’’) to the area within 1 day’s movement around the boundary of the UD (‘‘available’’). Tortoise UD sizes were significantly different across seasons for low-use (95%) but not for core-use (50%) AKDE levels. Tortoise UDs had greater canopy cover compared to available-but-unused areas at both AKDE levels. Potential mesic ground condition did not significantly differ between available and used areas. Our study revealed that tortoises vary the size of their home ranges throughout the year, whereas areas of intensive use or occupation tended to remain remarkably stable throughout the year. In seasons of extreme weather (hot or cold), tortoises seem to seek out areas of denser canopy cover that likely serve as thermal refugia. Based on our results, effective habitat identification may best be served by ensuring that canopy cover is at least equivalent to the values reported here to ensure sufficient refugia during extreme seasonal temperatures.

Guerra DA, Esque TC, Davis DR, Veech JA. 2025. Home range, seasonality, and the importance of canopy cover for Texas tortoises (Gopherus berlandieri). Herpetologica 81:224–235. [PDF]

Many amphibian species have declined throughout their ranges, and often the causes of those declines are poorly understood . Large-scale amphibian declines were first observed in the 1970s, and in the following decades, Batrachochytrium dendrobatidis (Bd) infection was determined as the cause of some of these declines . Retrospective studies allow us to evaluate historical disease patterns and are particularly valuable in species that are extirpated or extinct. The Black-spotted Newt (Notophthalmus meridionalis; Salamandridae) is an understudied species of salamander native to south Texas, USA, and northeastern Mexico that has shown alarming population declines over the past 70 years, most notably prior to 1980. Notophthalmus meridionalis has disappeared from the northern part of its range in recent decades. Multiple factors have likely contributed to its decline, including habitat loss, habitat fragmentation, and pesticide use. In the past century, the majority of native habitat in south Texas has been cleared for agriculture, urbanization, and roads, leaving small patches of fragmented habitat remaining across the species’ historical northern range. However, declines in N. meridionalis have also been observed in protected areas not affected by habitat loss and degradation. The reason for their disappearance from these areas is unknown, raising the question of whether Bd infections were contributing to their decline. Here, we assayed 314 N. meridionalis museum specimens to determine whether the historical presence of Bd may have contributed to population declines in this species.

Five new, short notes were recently published in Herpetological Review, most of which were written by student authors or have students as coauthors. Two of these notes were Natural History Notes documenting a new prey item and scavenging behavior in the Ornate Box Turtle (Terrapene ornata) (Davis and Davis 2024) and a new predator of the Plains Black-headed Snake (Tantilla nigriceps) (Summo Elias and Davis 2024). The other three notes were geographic distribution notes documenting the occurrence of three lizard species in three separate states. The first was a new county where Rough-tailed Geckos (Cyrtopodion scabrum) were found in Texas (Davis and Genter 2024), which only represents the second known county where this species occurs in the state (Davis and Genter 2024). Another note documented new distributional records of Common Wall Lizards (Podarcis muralis) in Indiana, which is also the first time they have been recorded in the state back after they were believed to have been eradicated (Mirtl et al. 2024). The final note was a formal documentation of the widely distributed (and rapidly spreading) Wood Slave (Hemidactylus mabouia) in Orange County, Florida (Summo Elias et al. 2024).

Shell studies of the Sonora Mud Turtle, Kinosternon sonoriense, have been limited except for a description of organisms living on the shell (Hulse 1976a) and a study on individual growth and morphometrics (Hulse 1976b), both involving individuals from Arizona, USA. Shell abnormalities in K. sonoriense were reported by Hulse (1976b) and included round pits up to 3-mm diameter in 26% of the specimens examined and a “corrugated carapace”, apparently due to “uneven deposition of additional bony material in the dermal skeleton” in 9% of the specimens examined. In his earlier paper, Hulse (1976a) reported epizoic algae, including Basicladia (now Arnoldiella) chelonum, on K. sonoriense in Arizona. While Hulse (1976b) noted that this alga could have been responsible for the pits, he rejected that conclusion because he observed many turtles with the algae present that lacked these pits. In the present work, we provide evidence for a similar shell-disease lesion progression throughout the range of K. sonoriense.

Christiansen JL, LaDuc TJ, Davis DR. 2024. Shell abnormalities in the Sonora mud turtle, Kinosternon sonoriense. Herpetological Review 55:193–198. [PDF]

The Moorish Gecko, Tarentola mauritanica, is a large species of gecko native to the Mediterranean Region of Europe and northern Africa. As with many other species of geckos, T. mauritanica has been introduced outside of its native range, often through jump dispersal and hitchhiking through the trade of commercial goods. Here, we summarize the occurrence of this species in the United States and present new data on an established population in Bexar County, Texas. Surveys conducted in 2022 and 2023 resulted in 59 vouchered specimens collected from 11 separate, distinct sites across the San Antonio metropolitan area. Photographic observations of this species in the area exist from 2018, and further support the widespread occurrence of this species in the region. Currently, T. mauritanica is known from three states in the USA (California, Florida, Texas), though it may soon spread into new areas. Future studies are needed to examine the ecological consequences of this non-native species.

Davis DR, Genter BW, LaDuc TJ. 2024. Invasion history of the Moorish gecko, Tarentola mauritanica (Squamata: Phyllodactylidae), in the USA, with new records of an established population in Texas. Reptiles & Amphibians 31:e21502. [PDF]

In a recent Perspective, Byrne (2023) emphasized that natural history museums “are essential hubs for research and education” but that their mission should be reimagined to focus on nonlethal collecting. We endorse many of the practices advocated by Byrne, including the storage of tissues, recordings, photos, and other data; embracing new technologies such as massively parallel DNA sequencing, μCT scanning, and stable isotope analysis; and large-scale digitization of collections and associated metadata. We also welcome the call to provide stable financial support to maintain and expand the infrastructure of existing collections. However, we do not support the call to use new technologies “to replace the need for whole animal bodies.” Byrne’s position overstates the potential of new technologies to replace specimen-based research and fails to acknowledge the importance of whole-organism–based research in building the foundations of modern biology and in continuing to promote new discoveries. Our goal is to underscore the tremendous value of ongoing, whole-organism specimen collection by highlighting some of the key scientific and societal gains that arise from this research.

Ranavirosis is a disease of high concern for amphibians due to widespread documentation of its lethal and sublethal impacts and its high transmission potential across populations and species. We investigated whether Spotted Salamander (Ambystoma maculatum) ranavirus prevalence and viral load were associated with habitat characteristics, genetic diversity, corticosterone levels, and body size. In 2015 and 2016, we sampled 34 recently created vernal pools in the Monongahela National Forest, West Virginia, USA. We collected tail clippings from 1,128 Spotted Salamander larvae and waterborne hormone samples from 436 of those larvae, along with eight environmental characteristics of the pools. Over the 2-yr period, we detected ranavirus in 62% of pools, with prevalence ranging from 0% to 63% (mean, 7.68%). Spotted Salamander size was positively correlated with ranavirus presence and viral load; however, we did not find associations between ranavirus prevalence or viral load and habitat characteristics, Spotted Salamander genetic diversity, relatedness, effective number of breeders, or corticosterone levels. The widespread occurrence of ranavirus in the vernal pools illustrates the potential for rapid natural introduction of the pathogen to created wetlands. Managers could consider monitoring local distributions of ranavirus before creation of new vernal pools to guide strategic placement of the wetlands to minimize occurrence and prevalence of this pathogen.

Cherax quadricarinatus (von Martens, 1868) is a large parastacid crayfish (Decapoda: Parastacidae) native to Australia and Papua New Guinea. Due to various factors, C. quadricarinatus is an emerging invasive species in an increasing number of regions across the world. Deleterious ecological effects of C. quadricarinatus introduction have been documented in many of these regions, and its spread has been monitored and restricted where possible. Previously, only a small, isolated population of C. quadricarinatus in southern California had been reported within the continental United States. Here, we report the collection of three adult C. quadricarinatus from Brownsville, Cameron County, Texas, the first record of this species in the state and only the second record for the continental United States. Given the connectivity of aquatic habitats in the area and the duration for which the population has likely been present, there is evidence that C. quadricarinatus is poised to invade subtropical watersheds of the southern United States. The ecological effects of C. quadricarinatus on aquatic ecosystems in the region are not yet fully understood, but further research is warranted to effectively mitigate negative impacts that may occur and to guide efforts to manage or eradicate these populations.