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Abstract This study explores patterning in δ¹⁸O values of tooth enamel in contemporary African herbivores from mainly C₃-dominated ecosystems. Evapotranspiration causes plants to lose H₂¹⁶O to a greater extent than H₂¹⁸O, leaving leaves enriched in¹⁸O. In eastern Africa, ES species (evaporation-sensitive species: those obtaining water from food) tend to have more positive δ¹⁸O_enamelvalues than EI species (evaporation-insensitive species: those heavily dependent on drinking water); the magnitude of the difference increases with increasing aridity. We find the same pattern applies in the winter and year-round rainfall region of southern Africa, allowing us to use δ¹⁸O_enamelin fossil animals to examine paleo-aridity. We apply this approach to infer aridity at Quaternary fossil assemblages from present-day winter and year-round rainfall zones, including Elandsfontein (ca. 1–0.6 Ma), Hoedjiespunt (ca. 300–130 ka), and Nelson Bay Cave (23.5–3 ka). This analysis suggests that (1) at various times during the Pleistocene, Elandsfontein and Hoedjiespunt environments were wetter than last glacial maximum (LGM) to Holocene environments at Nelson Bay Cave (year-round rainfall zone); and (2) considered alongside other evidence from the year-round rainfall zone, wetter conditions across the Pleistocene–Holocene transition at Nelson Bay Cave suggests that climate changes at near-coastal sites may be out of phase with the adjacent interior. 

With a rich sequence of floral and faunal remains spanning the past >65,000 years, Boomplaas Cave is among the more important paleoenvironmental archives from South Africa's southern Cape. However, over the last several decades, its paleoenvironmental records have been the subject of conflicting interpretations, fueling uncertainty over fundamental aspects of Quaternary climate change in the region. Most significantly, researchers have variably interpreted the fossil plant and animal assemblages dating to the Last Glacial Maximum (LGM) as indicating harsh and arid or humid and productive conditions. This review critically examines the paleoenvironmental evidence from Boomplaas Cave, focusing on its LGM deposits and how they relate to the contentious problem of moisture availability through time. We show that interpretations of aridity during the LGM either (i) lack robust ecological links between the evidence and the paleoenvironmental interpretation, or (ii) are based on spurious patterns arising from sampling effects. In contrast, interpretations of relatively humid conditions during the LGM are grounded in present-day ecological observations and are consistent with both local and regional paleoenvironmental datasets. Overall, the evidence strongly supports the characterization of the LGM as a time of relatively humid conditions, with the transition to the Holocene characterized by increasing aridity. Several lines of evidence from Boomplaas Cave further suggest that this phase of increased humidity was associated with a dominance of winter rainfall, in contrast to the aseasonal rainfall regime that characterizes the southern Cape today. 

For many animals, migration is an important strategy for navigating seasonal bottlenecks in resource availability. In the savannas of eastern Africa, herds of grazing animals, including blue wildebeest (Connochaetes taurinus), Thomson's gazelle (Eudorcas thomsonii), and plains zebra (Equus quagga), travel hundreds of kilometers annually tracking suitable forage and water. However, we know nearly nothing about migration among the extinct species that often dominated Late Pleistocene communities. Using serially sampled 87Sr/86Sr and δ13C, we characterize the prehistoric movement and diet of the enigmatic wildebeest Rusingoryx atopocranion from two localities (Karungu and Rusinga Island) in the Lake Victoria Basin of western Kenya. We find clear evidence for migration in all four individuals studied, with three 87Sr/86Sr series demonstrating high-amplitude fluctuations and all falling outside the modeled isoscape 87Sr/86Sr ranges of the fossil localities from which they were recovered. This suggests that R. atopocranion exhibited migratory behavior comparable to that of its closest living relatives in the genus Connochaetes. Additionally, individuals show seasonally-variable δ13C, with a higher browse intake than modern and fossil eastern African alcelaphins indicating behavioral differences among extinct taxa otherwise unrecognized by comparison with extant related species. That this species was highly migratory aligns with its morphology matching that of an open grassland migrant: it had open-adapted postcranial morphology along with a unique cranial structure convergent with lambeosaurine dinosaurs for calling long distances. We further hypothesize that its migratory behavior may be linked to its extinction, as R. atopocranion disappears from the Lake Victoria Basin fossil sequence coincident with the refilling of Lake Victoria sometime after 36 ka, potentially impeding its past migratory routes. This study characterizes migration in an extinct eastern African species for the first time and shapes our ecological understanding of this unique bovid and the ecosystems in which Middle Stone Age humans lived.