Cécile Blondel

This manuscript introduces trident, an R package for performing dental microwear texture analysis and subsequently classifying variables based on their ability to separate discrete categories. Dental microwear textures reflect the physical properties of the food, the feeding ecology of a given species, and niche partitioning when considering multi-specific communities. The trident package comes with independent functions and a user interface, trident, enabling easy and fast proficiency. It can import .SUR files, then remove aberrant peaks and possibly polynomial surfaces. Next, it can measure up to 24 texture parameters and their statistics of heterogeneity, generating 384 variables. It also ranks any number of variables using five different methods, displays the results in multivariate analyses, and exports the results into R, providing access to its large asset of libraries. We then present these features in three case studies, showing how trident helps answer questions commonly investigated by paleontologists and archaeologists. In the first case study, we separate four groups of domestic pigs based on their dietary composition. In the second case study, we identify microwear texture patterns in a large database of 15 primate species and relate these patterns to biomechanical and ecological factors. The third case study investigates the dental microwear textures of four extant ruminants to infer the diet of an extinct antelope from the Pleistocene of Greece. These case studies show how trident can leverage dental microwear texture analysis results.

The Ulm-Westtangente locality has yielded the most abundant vertebrate fauna from the Aquitanian stage in Germany. Its dating to the Mammal Neogene Zone 2a, a turnover in Cenozoic climate, makes it a crucial source for the understanding of faunal, paleoecological and paleoenvironmental specifics of the European Aquitanian. However, while most taxa from Ulm-Westtangente have been studied, little to no research has been conducted on the large herbivores, particularly on the two rhinocerotids Mesaceratherium paulhiacense and Protaceratherium minutum. Here, we used a multi-proxy approach to investigate the paleoecology of these two species. The remains of the smaller species P. minutum (438 to 685 kg) are twice as abundant as those of the larger M. paulhiacense (1389 to 2327 kg), but both display a similar age structure (~ 10% of juveniles, 20% of subadults and 70% of adults), mortality curves, and mild prevalence of hypoplasia (~ 17%). Results from dental mesowear, microwear, and carbon isotopes indicate different feeding preferences: both were C3 feeders but M. paulhiacense had a more abrasive diet and was probably a mixed feeder. Our study on rhinocerotids also yielded new paleoenvironmental insights, such as the mean annual temperature (15.8 °C) and precipitation (317 mm/year) suggesting rather warm and dry conditions.

The locality of Ulm-Westtangente yielded the richest vertebrate fauna from the Aquitanian of Germany. Its dating to the Mammal Neogene Zone 2a, a turnover in Cenozoic climate, makes it a crucial source for the understanding of faunal, palaeoecological and palaeoenvironmental specifics of the European Aquitanian. However, if most taxa from Ulm-Westtangente have been studied, very little to nothing has been done on the large herbivores and notably on the two rhinocerotids Mesaceratherium paulhiacense and Protaceratherium minutum . Here, we used a multi-proxy approach to investigate the paleoecology of these two species. The remains of the smaller species P. minutum (442 to 667 kg) are twice as abundant as those of the larger M. paulhiacense (1687 to 2576 kg), but both display a similar age structure (∼ 10 % of juveniles, 20 % of subadults and 70 % of adults), mortality curves, and mild prevalence of hypoplasia (∼ 17 %). Results from dental mesowear, microwear, and carbon isotopes indicate different feeding preferences: both were C3 feeders but M. paulhiacense had a more abrasive diet and was probably a mixed feeder. Our study on rhinocerotids also yielded new paleoenvironmental insights, such as the mean annual temperature (15.8 °C) and precipitation (317 mm/year) suggesting rather warm and dry conditions. Statements and Declarations: The authors have no relevant financial or non-financial interests to disclose. This study was funded by a post doctoral fellowship of the Alexander von Humboldt Foundation (Germany).

The late middle Miocene fossil-bearing lignite zones of the Mae Moh Basin, northern Thailand, have yielded a rich vertebrate fauna, including two species of Carnivora described thus far: the bunodont otter Siamogale thailandica (known from over a 100 specimens) and the large amphicyonid Maemohcyon potisati. Here we describe additional carnivoran material from Mae Moh comprising new remains of Maemohcyon potisati as well as remains of seven new carnivorans belonging to at least four families: a new species of Siamogale (S. bounosa), a new species of another otter (Vishnuonyx maemohensis), one representative of the genus Pseudarctos (a small amphicyonid), a new genus of Asian palm civet, Siamictis, one representative of another civet (cf. Viverra sp.), a new species of mongoose (Leptoplesictis peignei) and a Feliformia indet. This carnivoran assemblage constitutes one of the richest for the middle Miocene of eastern Asia and by far the richest for the Neogene of Southeast Asia.While the presence of new species indicates a certain degree of endemism for the Mae Moh Basin, paleobiogeographic cluster analyses conducted on carnivoran faunas from the middle and late Miocene of Asia indicates that a southern Asian biogeographic province, analogous to the current Oriental Realm, has existed since at least the middle Miocene. These results strengthen the observation that the Himalayan Mountains and Tibetan Plateau constitute significant physical barriers as well as an important climatic barrier (through the strengthening of monsoon systems) preventing north-south mammal dispersals in Asia since at least the middle Miocene.