Modern wild sheep, Ovis, is widespread in the mountain ranges of the Caucasus through Himalaya, Tibetan Plateau, Tianshan-Altai, eastern Siberia, and the Rocky Mountains in North America. In Eurasia, fossil sheep are known at a few Pleistocene sites in North China, eastern Siberia, and western Europe, but are so far absent from the Tibetan Plateau. We describe an extinct sheep, Protovis himalayensis, gen. et sp. nov., from the Pliocene of the Zanda Basin in western Himalaya. Smaller than the living argali, this new form shares with Ovis posterolaterally arched horncores and partially developed sinuses and possesses several transitional characters leading to Ovis. Protovis likely subsisted on C3 plants, which are the dominant vegetation in the Zanda area during the Pliocene. With the discovery of this new genus and species, we extend the fossil record for the sheep clade into the Pliocene of the Tibetan Plateau, consistent with our previous out-of-Tibet hypothesis. Ancestral sheep in the Pliocene were presumed adapted to high altitude and cold environments, and during the Ice Age, sheep became anatomically modern and dispersed outside of the Tibetan Plateau. Both this new fossil datum and the existing molecular phylogeny suggest that the Tibetan Plateau, possibly including Tianshan-Altai, represents the ancestral home range(s) of mountain sheep and that these basal stocks were the ultimate source of all extant species. Most sheep species survived along their Pleistocene route of dispersal, offering a highly consistent pattern of zoogeography. http://zoobank.org/urn:lsid:zoobank.org:pub:F2AEE746-0A5B-4F40-89B7-8EF0C04F21FD SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP Citation for this article: Wang, X., Q. Li, and G. T. Takeuchi. 2016. Out of Tibet: an early sheep from the Pliocene of Tibet, Protovis himalayensis, gen. et sp. nov. (Bovidae, Caprini), and origin of Ice Age mountain sheep. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2016.1169190.

Leporid remains are common in Quaternary fossil assemblages and are useful paleoenvironmental indicators. Identifying leporid fossils to species is challenging, though previous work has shown that identifications are more feasible if fossils can be narrowed down to a subset of potential species occurring across limited spatial scales. We sampled 120 adult and nine juvenile dentaries of six extant western North American species (Lepus americanus, L. californicus, L. townsendii, Sylvilagus audubonii, S. bachmani, and S. nuttallii) to establish useful characters for genus and species-level identification of late Quaternary leporid fossils in California. Most individuals can be differentiated from individuals of other species using a combination of lower third premolar enamel folding patterns and dental measurements. However, it is difficult to discriminate dental elements among L. californicus and L. townsendii and elements of S. nuttallii from S. audubonii, S. bachmani, and L. americanus. Here we present criteria for differentiating western leporid dental remains, apply the criteria to identify specimens recovered from several late Quaternary fossil deposits at Rancho La Brea (RLB), California, collectively known as Project 23, and reconstruct changes in relative fossil leporid abundances there. Using our criteria, we identified two extant species, S. audubonii and S. bachmani, among the Project 23 fossils. In addition to relative abundance changes across several RLB deposits, S. audubonii and S. bachmani generally become larger through time, possibly in response to local environmental changes. Establishing region-specific identification criteria as done here may prove useful for discerning morphologically similar species at prehistoric sites elsewhere.

The 'third pole' of the world is a fitting metaphor for the Himalayan-Tibetan Plateau, in allusion to its vast frozen terrain, rivalling the Arctic and Antarctic, at high altitude but low latitude. Living Tibetan and arctic mammals share adaptations to freezing temperatures such as long and thick winter fur in arctic muskox and Tibetan yak, and for carnivorans, a more predatory niche. Here, we report, to our knowledge, the first evolutionary link between an Early Pliocene (3.60-5.08 Myr ago) fox, Vulpes qiuzhudingi new species, from the Himalaya (Zanda Basin) and Kunlun Mountain (Kunlun Pass Basin) and the modern arctic fox Vulpes lagopus in the polar region. A highly hypercarnivorous dentition of the new fox bears a striking resemblance to that of V. lagopus and substantially predates the previous oldest records of the arctic fox by 3-4 Myr. The low latitude, high-altitude Tibetan Plateau is separated from the nearest modern arctic fox geographical range by at least 2000 km. The apparent connection between an ancestral high-elevation species and its modern polar descendant is consistent with our 'Out-of-Tibet' hypothesis postulating that high-altitude Tibet was a training ground for cold-environment adaptations well before the start of the Ice Age.

Pantherine felids ('big cats') include the largest living cats, apex predators in their respective ecosystems. They are also the earliest diverging living cat lineage, and thus are important for understanding the evolution of all subsequent felid groups. Although the oldest pantherine fossils occur in Africa, molecular phylogenies point to Asia as their region of origin. This paradox cannot be reconciled using current knowledge, mainly because early big cat fossils are exceedingly rare and fragmentary. Here, we report the discovery of a fossil pantherine from the Tibetan Himalaya, with an age of Late Miocene-Early Pliocene, replacing African records as the oldest pantherine. A 'total evidence' phylogenetic analysis of pantherines indicates that the new cat is closely related to the snow leopard and exhibits intermediate characteristics on the evolutionary line to the largest cats. Historical biogeographic models provide robust support for the Asian origin of pantherines. The combined analyses indicate that 75% of the divergence events in the pantherine lineage extended back to the Miocene, up to 7 Myr earlier than previously estimated. The deeper evolutionary origin of big cats revealed by the new fossils and analyses indicate a close association between Tibetan Plateau uplift and diversification of the earliest living cats.

The stable carbon isotope ratios of tooth enamel from 89 herbivores from the Dove Spring Formation (DSF) of the El Paso Basin, western Mojave Desert, California, were analyzed to determine if C4plants may have been present in the late Miocene of southern California. Taxa analyzed include antilocaprids, castorids, camelids, equids, gomphotheriids, merycoidodontids, and rhinocerotids. The atmospheric CO2-δ13C value has varied significantly in the geologic past, leading to changes in the δ13C values of plants and tooth enamel. The estimated δ13C value of atmospheric CO2in the middle to late Miocene is − 5.8 ± 0.2‰, making the pure C3diet cutoff value higher than the modern by ~ 2‰. Given this, much of the evidence of an early spread of C4, which inappropriately uses the modern C3diet cutoff value, may be a false signal from water-stressed C3plants and the amount of C4biomass in the geologic past may have been over-estimated. The enamel-δ13C values of all taxa sampled are − 10.1 ± 1.1‰ (n = 89). Accounting for the changes in the δ13C values of atmospheric CO2, enamel-δ13C values from the DSF indicate that herbivores from that area had C3diets and lived in an environment dominated by C3plants. Serial enamel isotope data from the DSF revealed negligible intra-tooth variations in the δ13C values, confirming that these herbivores consumed C3plants year-round. If the C4photosynthetic pathway did spread to southern California prior to the rapid, global rise in C4in the late Miocene, the taxa sampled did not incorporate C4biomass into their diets. The results of the stable carbon isotope analysis, along with the evidence from the rock record and the life habits of the fossil taxa present, indicate that the El Paso Basin consisted of diverse habitats including C3grasslands, wooded C3grasslands, and riparian forests.

The spread of grasslands in the Miocene and of C4 grasses in the late Miocene-Pliocene represents a major development in terrestrial plant evolution that affected the climate system and faunal evolution. The macrofossil record of grasses is sparse, likely due to the limited preservation potential of grasses. Diagnosis of the C3 or C4 photosynthetic pathway depends on preservation of both cellular structures and organic carbon for isotope analysis. Here we analyze the anatomical and isotopic composition of newly-collected grass fossils from the Dove Spring Formation, Red Rock Canyon State Park, California, USA, located in the El Paso Basin on the western side of the Basin and Range Province, a site previously identified as one of the earliest known C4 grass fossil bearing localities. We analyzed the anatomical and geochemical characteristics of these new grass fossils dated to 12.01–12.15 Ma. The fossils analyzed in this study include grass shoots and in cross-section display anatomy indicative of the C3 photosynthetic pathway. We isolated organic carbon from the stem fossils and determined the carbon isotopic composition to be − 24.8 ± 0.5‰. Together, the anatomical and geochemical analyses confirm that these plants used the C3 photosynthetic pathway. Our findings are consistent with dietary evidence based on tooth enamel from grazing mammals of available C3 resources in the same sections. These newly reported Miocene-age C3 grass fossils contribute to a sparse macrofossil record of grass evolution. Overall, paleoecological reconstructions at this site indicate more humid conditions during the Miocene compared to the modern Mojave Desert with C3 grasses and diverse grazing mammals.