Grayia Günther 1858 is a genus of relatively large (1.2–2.5 m) aquatic Afrotropical snakes. Recent molecular phylogenies recovered Grayia in its own distinct subfamily (Grayiinae), which was supported as the sister group to Colubrinae. Tropical African snakes are generally understudied, so the relationships within Grayia are poorly known. High degrees of intra- and interspecies variation can make identification difficult, and previous studies involving Grayia included misidentified specimens in other genera. The goal of this study is to create a phylogenetic tree that can be used to understand the relationships and taxonomy of Grayia via an integrative taxonomic approach that combines molecular data for 60 specimens and morphological data for 719 specimens. Two nuclear (BDNF, NT3) and four mitochondrial genes (COI, cyt b, 16S, and ND4) were used to construct phylogenetic trees with Maximum Likelihood and Bayesian Inference algorithms. The phylogenetic trees recovered two clades, Grayia caesar + G. tholloni and G. ornata + G. smythii, which the time-calibrated Bayesian Evolutionary Analysis Sampling Tree (BEAST) analysis estimated to have diverged from each other in the mid-Oligocene. This deep divergence, combined with distinct morphological differences, led us to resurrect the name Xenurophis Günther 1863 as a subgenus [G. (Xenurophis) caesar, G. (Xenurophis) tholloni]. Molecular and morphological evidence further supports a new cryptic species of Grayia from the Upper and Middle Congo River and its tributaries. This new species is estimated to have diverged from its nearest sister species, G. ornata, in the Late Miocene—which coincides with the divergence dates of sister taxa within other Central African snake genera. Grayia ornata sensu stricto was found to consist of several evolutionary lineages, which mirror the patterns recovered in other Central African vertebrates.

Anthropogenic activities in disturbance-mediated ecosystems might affect certain ecological processes that, in turn, can affect the stability and resilience of those ecosystems. In upland pine forests, land-use practices such as intensive silviculture and fire suppression have contributed to the loss of diversity-rich pine savannahs throughout the southeast. Whereas the application of management strategies has been shown to alter forest structure in pine ecosystems, less is known about how these efforts influence pathways of energy flow and the consumer–resource relationships therein. Here, we investigated the effects of frequency of forest management on the trophic structure and resource use of snake communities in two pine forests under high and low frequencies of management (i.e., shorter fire return intervals and thinning versus longer fire return intervals and limited thinning). We sampled snakes, prey, and dominant basal resources across each site for three summers from 2018 to 2020. Using stable isotope analysis, we compared community-wide metrics of trophic structure and generated isotopic mixing models to determine the relative contribution of resources to snake consumers. We found that the high-frequency site supported an increased diversity of snake species, and that species exhibited increased trophic redundancy. The low-frequency site supported fewer snake species that relied on a wider range of resources, and occupied a wider range of relative tropic positions. Mixing models of consumer–resource relationships, and prey relative abundance, indicated that snakes were more generalized in their resource use in the high-frequency site, and utilized a broader diversity of prey more evenly. In contrast, snakes in the low-frequency site were more specialized in their prey use. We suggest that anthropogenic activities mimicking natural disturbances can drive food-web structure in these forest ecosystems. Increased frequency of forest management practices such as prescribed fires and thinning operations might support snake species diversity while also increasing trophic redundancy. Consequently, such management applications can lead to greater stability and resilience in pine-forest ecosystems. Our research further highlights the importance of ecological restoration that incorporates food-web perspectives to ensure the health of pine ecosystems.