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Fossil gibbons are exceedingly rare, with much of the hylobatid fossil record and, consequently, hylobatid evolutionary history remaining unknown. Kapi ramnagarensis was described as a stem hylobatid on the basis of an isolated lower right M3 from ~13.0-12.5 Ma deposits surrounding Ramnagar (J&K), India. This interpretation was recently challenged, with alternative hypotheses suggesting that it is instead a stem catarrhine or a strangely derived pliopithecoid that has converged on hylobatid morphology. A series of morphological features were said to distinguish Kapi from fossil and extant hylobatids; notably, however, none of these features were examined or compared using quantitative analyses. Here, we further examine the dental morphology of Kapi, providing quantitative analyses to critically evaluate the hypothesis that Kapi represents a stem catarrhine or pliopithecoid rather than a stem hylobatid. Results demonstrate that none of the claimed differences between Kapi and hylobatids hold up under closer scrutiny, and multivariate discriminant analyses taking size and shape into account strongly support Kapi as a hylobatid with high posterior probabilities. Although only represented by a single lower molar, Kapi remains the most compelling candidate for the earliest known hylobatid in the fossil record and thus likely documents the simultaneous arrival of lesser and great apes to Asia during the Middle Miocene. 

Abstract The fossil record of treeshrews, hedgehogs, and other micromammals from the Lower Siwaliks of India is sparse. Here, we report on a new genus and species of fossil treeshrew, specimens of the hedgehog Galerix , and other micromammals from the middle Miocene (Lower Siwalik) deposits surrounding Ramnagar (Udhampur District, Jammu and Kashmir), at a fossil locality known as Dehari. The treeshrew from Dehari ( Sivatupaia ramnagarensis n. gen. n. sp.) currently represents the oldest record of fossil tupaiids in the Siwaliks, extending their time range by ca. 2.5–4.0 Myr in the region. Dietary analyses suggest that the new tupaiid was likely adapted for a less mechanically challenging or more frugivorous diet compared to other extant and fossil tupaiids. The occurrence of Galerix has only been recently documented from the Indian Siwaliks and the Dehari specimens help establish the likely presence of a relatively large Siwalik Galerix species in the Ramnagar region. In addition to the new treeshrew and hedgehogs, new specimens of the rodents Kanisamys indicus , Sayimys sivalensis , and Murinae indet. from Dehari help confirm that age estimates for the Ramnagar region are equivalent to the Chinji Formation in Pakistan, most likely corresponding to the middle to upper part of the Chinji Formation. UUID: http://zoobank.org/56fb160c-2df8-4cd3-be91-af4dc02d0979 

The fossil record of ‘lesser apes’ (i.e. hylobatids = gibbons and siamangs) is virtually non-existent before the latest Miocene of East Asia. However, molecular data strongly and consistently suggest that hylobatids should be present by approximately 20 Ma; thus, there are large temporal, geographical, and morphological gaps between early fossil apes in Africa and the earliest fossil hylobatids in China. Here, we describe a new approximately 12.5–13.8 Ma fossil ape from the Lower Siwaliks of Ramnagar, India, that fills in these long-standing gaps with implications for hylobatid origins. This ape represents the first new hominoid species discovered at Ramnagar in nearly a century, the first new Siwalik ape taxon in more than 30 years, and likely extends the hylobatid fossil record by approximately 5 Myr, providing a minimum age for hylobatid dispersal coeval to that of great apes. The presence of crown hylobatid molar features in the new species indicates an adaptive shift to a more frugivorous diet during the Middle Miocene, consistent with other proposed adaptations to frugivory (e.g. uricase gene silencing) during this time period as well. 

Abstract Bone modeling and remodeling are aerobic processes that entail relatively high oxygen demands. Long bones receive oxygenated blood from nutrient arteries, epiphyseal‐metaphyseal arteries, and periosteal arteries, with the nutrient artery supplying the bulk of total blood volume in mammals (~ 50–70%). Estimates of blood flow into these bones can be made from the dimensions of the nutrient canal, through which nutrient arteries pass. Unfortunately, measuring these canal dimensions non‐invasively (i.e. without physical sectioning) is difficult, and thus researchers have relied on more readily visible skeletal proxies. Specifically, the size of the nutrient artery has been estimated from dimensions (e.g. minimum diameters) of the periosteal (external) opening of the nutrient canal. This approach has also been utilized by some comparative morphologists and paleontologists, as the opening of a nutrient canal is present long after the vascular soft tissue has degenerated. The literature on nutrient arteries and canals is sparse, with most studies consisting of anatomical descriptions from surgical proceedings, and only a few investigating the links between nutrient canal morphology and physiology or behavior. The primary objective of this study was to evaluate femur nutrient canal morphology in mice with known physiological and behavioral differences; specifically, mice from an artificial selection experiment for high voluntary wheel‐running behavior. Mice from four replicate high runner (HR) lines are known to differ from four non‐selected control (C) lines in both locomotor and metabolic activity, withHRmice having increased voluntary wheel‐running behavior and maximal aerobic capacity (VO₂max) during forced treadmill exercise. Femora from adult mice (average age 7.5 months) of the 11th generation of this selection experiment were μCT‐scanned and three‐dimensional virtual reconstructions of nutrient canals were measured for minimum cross‐sectional area as a skeletal proxy of blood flow. Gross observations revealed that nutrient canals varied far more in number and shape than prior descriptions would indicate, regardless of sex or genetic background (i.e.HRvs. C lines). Canals adopted non‐linear shapes and paths as they traversed from the periosteal to endosteal borders through the cortex, occasionally even branching within the cortical bone. Additionally, mice from bothHRand C lines averaged more than four nutrient canals per femur, in contrast to the one to two nutrient canals described for femora from rats, pigs, and humans in prior literature. Mice fromHRlines had significantly larger total nutrient canal area than C lines, which was the result not of an increase in the number of nutrient canals, but rather an increase in their average cross‐section size. This study demonstrates that mice with an evolutionary history of increased locomotor activity and maximal aerobic metabolic rate have a concomitant increase in the size of their femoral nutrient canals. Although the primary determinant of nutrient canal size is currently not well understood, the present results bolster use of nutrient canal size as a skeletal indicator of aerobically supported levels of physical activity in comparative studies.