A new fossil murid from Eboliang III Anticline in western Qaidam Basin, northern Qinghai-Xizang Tibetan, China, is described. Qaidamomys fortelii gen. & sp. nov. from Eboliang III Anticline is characterized by its large size, high crown and robust cusps in molars. It possesses a mixture of characters from the Apodemus and Occitanomys groups, which suggests an early divergence from the murid stem lineages. Based on the associated mammalian assemblages, ostracod biostratigraphy, and magnetostratigraphy, the occurrence of the new genus is roughly restricted to the early Late Miocene (early Bahean Chinese Land Mammal Stage/Age), in the 9.4 to 11 Ma interval. The high crown and robust cusps of the new species indicate its adaptation to the tough and coarse food. It also hints that in the early Late Miocene, the western Qaidam Basin was already rather arid.

Dwarf elephants are quite well known from the western Mediterranean islands, but they are still poorly documented in most eastern Mediterranean islands. This paper reports on the discovery of a third lower molar of a dwarf elephant from the island of Kassos, which is situated in the southern Aegean, between Crete and Karpathos. This molar is determined as Palaeoloxodon aff. creutzburgi, a dwarfed species known from the Late Pleistocene caves and deposits in Crete and derived from the mainland straight-tusked elephant P. antiquus. An upper molar (M3) from the island of Dilos, previously referred to Elephas antiquus or E. mnaidriensis, is also redescribed. It is almost identical to the upper molars of a paleoloxodontine elephant from Naxos. Its small size and lack of sufficient comparative material lead us to determine it as Palaeoloxodon sp. The palaeogeographic evolution of the Aegean region during the Pleistocene and its impact on the dispersal of elephants in the Aegean islands are discussed.

A chronofauna is a geographically restricted collection of interacting animal populations that maintains its base structure over a long period of time. We describe a simple computational method that can identify candidate chronofaunas on the basis of presence-absence matrices only: A candidate chronofauna is a collection of sites that share an exceptionally large number of taxa with the defining site of the chronofauna. We show examples of candidate chronofaunas in the NOW data (see  http://www.helsinki.fi/science/now).

The bovid faunas of the Siwaliks (Pakistan) show little change in structure or higher level taxonomy through much of the Middle and Late Miocene. Species of Bovinae and Antilopinae are abundant and Caprinae very rare.

Evolution is commonly studied at different levels, from genes to species. It has been questioned whether all these levels are actually real, although it now seems accepted by most scientific investigators that more than one level is actually targeted by selection. Intriguingly, despite the importance of biological interaction is relevant to the course of evolution (and to the level to which selection applies) the obvious locus for biological interaction, the community, has received little evolutionary attention by mammal paleontologists. Herein, we investigate the concept of a biochron, which is the approximation closest to a real community in the paleontological world, and its applications. Then, we offer some clues as to how to use biochrons for investigating community evolution, and explain why paleontological community evolution is a partly novel, highly promising field of research within the realm of paleobiology.

Understanding the ¹³C and ¹⁵N enrichments between primate diet and hair is necessary for reconstructing primate diets and ecology. However, dietary lipids need to be controlled for in order to accurately estimate the hair ¹³C and ¹⁵N enrichment factors (ϵ*). We report diet-hair ¹³C and ¹⁵N enrichment factors for vervet monkeys (Chlorocebus aethiops sabaeus) based on a controlled diet study in captivity. The vervet monkeys were fed a standard monkey chow exclusively. The ^13Cϵ*_hair-diet and ^15Nϵ*_hair-diet values for male adults were 2.8‰ and 2.9‰, respectively; those for lactating females were 2.4‰ and 2.2‰, respectively. The isotope enrichment between hair from infant (ca. 3 months of age) and hair from its mother were ^13Cϵ*_{hair(infant-mother)} and _15Nϵ* and ^15Nϵ* _{hair(infant-mother)} were 0.7‰ and 1.8‰, respectively.

The horse lineage (family Equidae) represents one of the clearest acquisitions of complicated derived dental morphology from a more generalized ancestor. Here we investigate the change in dental complexity (orientation patch count rotated, OPCR) during the evolution of key members of this group. A clear linear increase in dental complexity over evolutionary time is apparent when complexity is measured at high resolution (125 to 175 rows per tooth). The taxa examined also show a linear scaling of OPCR with varying resolution. The slope of this relationship is also a key distinguishing factor among taxa, designated as OPCRS. We found that successive increases in dental complexity are due to the addition of finer-scale morphological features. The study sets the scene for a more detailed investigation into additional members of the Equidae.

The omasum of pecoran ruminants (which is absent in tragulids) and shorter gestation periods in non-giraffid crown pecorans (as opposed to giraffids) could represent cases of key innovations that caused disparity in species diversity in extant ruminants. Literature suggests that the different ruminant groups inhabited similar niche spectra at different times, supporting the ‘increased fitness’ interpretation where a key innovation does not mainly open new niches, but allows more efficient use of existing ones. In this respect, we explored data on fossil species diversity of Afro-Eurasian ruminants from the Neogene and Quaternary. Tragulid and giraffid diversity first increased during the Early/Middle Miocene with subsequent declines, whereas bovid and cervid diversity increased distinctively. Our resulting narrative, combining digestive physiology, life history and the fossil record, thus provides an explanation for the sequence of diversity patterns in Old-World ruminants.

House mice from 24 Scottish and Faroese islands show positive correlation of skeletal size with island area, conforming to a model of resource limitation in very small islands. Molar size is not correlated with island size, suggesting greater genetic canalization; smaller individuals have larger tooth to body size ratio. The size variation may have a simple genetic basis or may be ecophenotypic. The offset between skeletal and molar size has potential use in the fossil record as a marker for these rapid effects, while longer-term evolutionary change reverts to approximate tooth—body size isometry. Collation of related studies indicates frequently deterministic relationships of small-mammal body size to island size. The parameters of the relationship (positive, negative or parabolic) vary widely with case study according to biotic and abiotic factors. In the present study there was no relationship of mouse size to any variable (e.g. presence of competitors) except island area.

Mesowear III is a new form of mesowear that uses separately the mesial and distal surfaces of enamel band 2 of the upper second molar to differentiate between a browsing and a grazing diet. The enamel band of browsers is flat and planar, in grazers it contains gouges and sub-facets which eventually become round. Mesowear III scores these shapes on a scale 1–4; score 1 represents the typical browser and score 4 represents a typical grazer. Differences in diet can also be studied by observing the junction between the mesial and distal side of the enamel band (j point); the j point is sharper and well defined in browsers, while it is rounder or non-existent in grazers. Wild browsers, grazers, and mixed feeders separate well using mesowear III. The wild taxa data were similar to mesowear III of experimental goats that were fed a controlled grazing or browsing diet (species of plants known). In addition, the browsing versus the grazing goat mesowear III signal becomes more distinct from each other by 40 days of feeding. Mesowear III so far gives a finer signal than previous mesowear (I and II).

Mesowear analysis is a powerful tool for paleodiet reconstruction in ungulates. In this study, we apply this method to archeological data. We conduct mesowear analysis on cheek teeth of medieval horses from the Levänluhta site in Ostrobothnia, western Finland and, for comparison, we study medieval and post-medieval horse teeth from Viljandi and Tallinn, Estonia. Our results show attrition-dominated mesowear indicating browsing diet for the medieval Levänluhta horses, while the Viljandi horses have mesowear indicating more mixed diet. Mesowear on teeth from Tallinn horses suggest primarily grazing-like abrasive diet. Differences maybe due to different diet of horses in Finland and Estonia, or may point to seasonal differences in diet and thus indicate different times of death for these horses.

We present dental enamel stable carbon and oxygen isotope data, histological analyses of daily cross striations and perikymata, and microwear data of Late Miocene primates Indopithecus and Sivaladapis nagrii and an early Pleistocene primate Theropithecus delsoni, known from the Indian Siwaliks. The results indicate that the Late Miocene giant ape Indopithecus had a C₃ diet, likely including nuts, seeds and fruits with hard cover, and most probably lived in a seasonal forest that experienced long dry and wet seasons. While the seasons changed as depicted by intra-annual variation in δ¹⁸O values, the C₃ component of diet was similar throughout the year, as indicated by consistent δ¹³C values. Sivaladapis nagrii dental enamel δ¹³C and δ¹⁸O values, striations and pit percentages indicate that this small primate (3 kg) was a C₃ mixed folivore-frugivore. Theropithecus delsoni dental enamel δ¹³C and δ¹⁸O values and microwear pattern indicate a diet comprising mainly C₄ grasses or sedges.

The threat of wear to dental enamel from hard particles of silica or silicates may have exerted great selective pressure on mammals. Increasing the hardness of enamel helps to forestall this, but capacity for variation is small because the tissue is almost entirely composed of hydroxyapatite. Hard though it is, enamel also displays considerable toughness, which is important in setting the sharpness of particles (defined as an attack angle) necessary to wear it. Added to the threat from environmental silica(tes) are phytoliths, particles of opaline silica embedded in plant tissues. We show here that phytoliths have very different properties to grit and dust and are unlikely to wear enamel. However, phytoliths would tend to fracture between teeth under similar conditions, so resembling natural agents of wear. In this context, we suggest that phytoliths could represent an example of mimicry, forming an example of a feeding deterrent operating by deceit.

We studied dental complexity in Laoncistes aenigmomus to place this unique rodent species into a comparative context. The complexity of cheek teeth of Laoncistes are within the range of that for omnivorous mammals feeding predominantly on plants or that for herbivorous mammals. In a comparative sample of predominantly herbivorous hystricomorph rodents, only the degu (Octodon degus) and the chinchilla (Chinchilla chinchilla) have less complex cheek teeth than Laonastes. We also used ethanol fixed stomachs and a silicone cast of stomach of five Laonastes to study its macroscopic and microscopic gut anatomy. The stomach of Laonastes has four elongated chambers that are partially sacculated. The stomach of Laonastes differs microscopically from the typical rodent stomach: most of the epithelium is glandular, and non-glandular stratified squamous epithelium can be found only in the sulcus that is microscopically homogenous. Microscopic screenings showed that the digesta was similar in all stomach compartments. The mean renal medullary thickness (RMT) in this species is low indicating that its ability to concentrate electrolytes in the urine is low. We discuss the dentition and the stomach morphology of Laonastes in relation to observations on its natural diet.

Three functional aspects (jaw movement, collapse of lophs by wear, and molar wear gradient) are described for Lophiodon and compared with typical lophodont dentitions in other mammals, e.g., Macropus, Pyrotherium and Deinotherium. The jaw movement is deduced from striations and guiding rails. In Lophiodon only phase I of the power stroke is documented by facets, whereas a minor phase II occurs in Macropus. During phase I the lophs perform two functions: cutting when the crests are passing each other, and compressing the bolus during further interlocking. When dentine is exposed the lophs collapse and lose their trenchant function and are grinding only. The sudden collapse of the lophs is partially due to the abrasion within the compression chamber, as seen in Dendrolagus. The molar wear gradient (the differential wear between the first and last molars) is low in Pyrotherium, intermediate in Lophiodon, and Deinotherium as compared with a low molar wear gradient in Tapirus or a high gradient in Macropus.

Kleiber suggested that mammalian metabolic rate scales with body mass at M_b^3/4. Bigger animals use relatively less energy. Gould reasoned that teeth should scale the same way given caloric need. In many cases though, cheek tooth occlusal area increases isometrically, one-to-one with body mass (i.e., M_b^2/3). Fortelius reconciled the discrepancy by noting that larger mammals also chew slower, so a given amount of food per bite but few bites per unit time could still mean metabolic scaling of energy consumed in a day. Here I revisit dental allometry, referencing new studies of tooth size, muscle mass, chewing rate, and food fracture scaling. Early predictions have held up reasonably well through the decades, though many more factors involved have emerged. These can be difficult to parse for intepreting deviations from expected tooth size in fossil mammals, including early hominins. Still, relative tooth size variation can help us generate dietary hypotheses.

Here we review published molar wear rates, measured in terms of tooth height loss per year (mm yr^-1) published on natural populations of ungulates (25 species), rodents and lagomorphs (Glires; 14 species) and macropodid marsupials (seven species). Although the data are limited, they nevertheless reveal consistent patterns, and raise new questions. Among ungulates, wear rates are uncorrelated with body mass but are positively correlated with hypsodonty. Browsers show lower wear rates than do mixed feeders or grazers. Percentage of grass in the diet shows a non-linear relationship with wear rates suggesting that levels of dietary abrasives result from a complex interaction among forages, habitat characteristics and feeding behaviours (whether or not grass itself is a significant abrasive agent). Rodents exhibit higher wear rates, and kangaroos lower wear rates, than do ungulates feeding on similar diets. Hypselodont rodents and lagomorphs show rates of molar wear an order of magnitude higher than do grazing ungulates.

This study explores the extent to which researchers might be able to interpret a fauna's paleoecology using mesowear analysis on ungulate maxillary molars when there are diverse taxa represented by few specimens. We compared our mesowear results on Maragheh ungulates with those of extant ungulates and with known mesowear score distributions of the two classical Greek Pikermian faunas of Samos and Pikermi, and with the late Miocene of China. The Maragheh equid and bovid species display a range of dietary abrasiveness, whereas the giraffids and chalicothere have fairly abrasive mesowear signals. Despite small sample sizes for some taxa, our results are consistent with long-held taxon-based interpretations of Maragheh paleoecology: a Pikermian woodland habitat. In addition, our results are consistent with climatic changes of the Paratethyan realm at the end of the Miocene.

Ecometrics is the study of the relationship between organismal traits and environments. This study used Monte Carlo methods to assess the effects of extinction, extirpation, and exotic species on ecometric correlations at the continental scale. These potentially confounding processes arise from anthropogenic activities, taphonomic biases in fossil assemblages, and selective mass extinctions. Random, independent local extinctions introduced a predictable downward bias in ecometric correlations, which can be corrected by rarefaction if correlations are being estimated from fossil assemblages. Random global extinctions on species have a less predictable effect on ecometric correlations and introduce pronounced effects if more than 25% of the continental fauna is affected; however, global extinctions do not bias the estimation of R² even though they increase its uncertainty. Selective extinction and introduction of exotic species had little impact on ecometric correlations, though caution is urged in generalizing this result.

In this study, we synthesize available data from isotopes, sedimentology and climate modelling together with an extensive mesowear analysis of North Chinese “Hipparion” faunas of Baode. We build on previous research and enlarge the range of analysed localities. Our results show that climate during accumulation of the older localities (7.5 Ma) was more humid than that of the youngest locality (5.7 Ma), while the intermediate localities (∼6.5 Ma) accumulated under variable climatic conditions. Our results generally confirm those of previous studies, but highlight temporal and spatial variation within localities. We suggest that this is caused by variation in monsoon strength as evidenced by various proxy records.

Faunal assemblages consist of immigrants, endemics and long-term residents; changes in proportions of these categories through time reflect general aspects of faunal stability and turnover. To study stability and change in the long biostratigraphic succession of Miocene terrestrial mammalian faunas recorded mainly in the Potwar Plateau Siwaliks of Pakistan, we distinguish long-term residents and assess new appearances as endemic vs. immigrant components. Our data represent the biogeography of the northern Indian subcontinent, but because neighboring areas of similar age are not as well known, virtually all species are found only there, and the proportion of the fauna that is immigrant is not apparent. We use preceding faunal assemblages to judge whether individual species might have originated there. We find many long-term residents in the Siwaliks, and of new species, most are immigrants and fewer are likely to have originated endemically. Siwalik rodents and artiodactyls show high rates of immigration for both during the early middle Miocene, followed by declining immigration but continuing residents. In the late middle Miocene both groups show stability, with a high proportion of long-term residents, and high endemism among rodents. In contrast, late Miocene rodent and artiodactyl patterns differ. Rodents decline in diversity but show increased immigration and new long-term residents; artiodactyls show turnover but then recover with many persisting residents.

We studied the multivariate morphospace of a sample of 216 extant carnivoran species. Emphasis was placed on statistical patterns below the family level in the five largest families. Canidae and Felidae had small morphospaces, indicating low functional richness. Their species are highly non-randomly located in morphospace, hence low functional evenness. Clades at the subfamily level showed no patterning. Mustelidae had the greatest functional richness and were non-randomly distributed. There was partial subfamily patterning, with Lutrinae standing out as distinct. Herpestidae and Viverridae had intermediate functional richness and were randomly distributed in morphospace, showing high functional evenness. Subfamilial clades showed distinct patterning, especially in Viverridae, where the four subfamilies occupy distinct parts of morphospace.

Four types of taxon-free analysis of mammalian faunas are discussed to come to an understanding of the degree to which they are independent of taxonomy. Species richness patterns and size distributions of faunal assemblages provide general indications of palaeoecology and are based entirely on species identifications; ecomorphology targets specific taxonomic groups, but within the group it is partly independent of taxonomy; community ecology describes mammalian communities by their levels of diversity within distinct ecological categories rather than by their species, and two approaches are based either on qualitative evidence (ecological diversity) or on quantitative evidence, combining ecomorphological data for whole communities (community ecomorphology). No method is entirely taxon-free, but all have stronger ecological foundations than methods based on linking fossil species of unknown habitat with their supposed habitats based on their relationships with their living relatives.