Oscar Sanisidro

• Postdoctoral Researcher at University of Alcalá

Proboscideans were keystone Cenozoic megaherbivores and present a highly relevant case study to frame the timing and magnitude of recent megafauna extinctions against long-term macroevolutionary patterns. By surveying the entire proboscidean fossil history using model-based approaches, we show that the dramatic Miocene explosion of proboscidean fun...

Since prehistory, humans have altered the composition of ecosystems by causing extinctions and introducing species. However, our understanding of how waves of species extinctions and introductions influence the structure and function of ecological networks through time remains piecemeal. Here, focusing on Australia, which has experienced many extin...

The fossil record provides direct evidence for the behavior of biological systems over millions of years. In doing so, paleontological information becomes a key source to study the evolution of ecosystems and how they responded to major environmental shifts. Using network analysis over a dataset of worldwide large herbivores spanning the past 60 My...

A large collection of dicerorhine rhinoceros remains, here identified as Pliorhinus ringstroemi, were studied from the Late Miocene deposits of the Linxia Basin, eastern Asia. The new specimens include several complete skulls with for the first-time preserved premaxillae, providing new knowledge on the morphology and allowing a preliminary investig...

Ammitocyon kainos, Morales et al, es un anficiónido hipercarnívoro del Vallesiense del Cerro de los Batallones, Madrid, España. A grandes rasgos posee una combinación de características anatómicas no presente en ningún otro representante del Orden Carnivora tanto actual como extinto. Por un lado, su dentición postcanina es uno de los modelos más hi...

Horses became ubiquitous elements of Cenozoic communities and reached high diversity in Neogene times. Most accounts of their diversification history have so far focused on the Early Miocene cladogenesis of the subfamily Equinae (the so-called “grazing horses”), interpreting raw diversity counts at face value. In this chapter, we reconstruct specia...

Several scenarios have been proposed to explain rapid net size increases in some early Cenozoic mammalian lineages: sustained and gradual directional change, successive occupation of adaptive zones associated with progressively larger body sizes, and nondirectional evolution associated with branching events in combination with higher diversificatio...

The iconic sabretooth Homotherium is thought to have hunted cooperatively, but the origin of this behaviour and correlated morphological adaptations are largely unexplored. Here we report the most primitive species of Amphimachairodus (Amphimachairodus hezhengensis sp. nov.), a member of Machairodontini basal to Homotherium, from the Linxia Basin,...

Dental morphology is a major aspect of ecological and evolutionary studies of both extant and fossil mammalian species. Mammalian dentitions are diverse feeding systems that can be defined through continuous numerical descriptors of the enamel pattern. We developed a comprehensive toolkit to quantify complex occlusal enamel patterns from two‐dimens...

Food webs influence ecosystem diversity and functioning. Contemporary defaunation has reduced food web complexity, but simplification caused by past defaunation is difficult to reconstruct given the sparse paleorecord of predator-prey interactions. We identified changes to terrestrial mammal food webs globally over the past ~130,000 years using ext...

The family Rhinocerotidae, also referred to as ‘true rhinoceroses’, is one of the multiple perissodactyl lineages that have independently evolved large body sizes, lophodonty (fully developed crests between dental cusps), a simplified anterior dentition, and the molarization of the premolars. During the last decades, descriptions of novel fossil co...

Els Casots is one of the richest fossil vertebrate sites of the Vallès-Penedès Basin (Catalonia, Spain). It was discovered in 1989 and excavated briefly during the 1990s, resulting in the recovery of thousands of remains and the erection of several new mammal species. Excavations were resumed in 2018 and continue to date. Here we provide updated re...

Proboscideans were keystone Cenozoic megaherbivores and present a highly relevant case study to frame the timing and magnitude of recent megafauna extinctions against long-term macroevolutionary patterns. By surveying the entire proboscidean fossil history using model-based approaches, we show that the dramatic Miocene explosion of proboscidean fun...

In the present paper, we describe the craniodental remains of three individuals of an amphicyonid previously determined as Thaumastocyon sp. from the late Miocene (c. 9.1 Ma) pseudokarstic site of Batallones-3. Dentognathic differences in relation to other Thaumastocyoninae enable a new taxon, Ammitocyon kainos gen. et sp. nov., to be defined; it i...

Relatively large new samples of the rare plesiadapid mammal Chiromyoides are reported from upper Paleocene rocks exposed along the eastern flank of the Rock Springs Uplift and the adjacent Washakie Basin in southwestern Wyoming. These specimens form the basis for the new upper Tiffanian species Chiromyoides kesiwah and enhance our knowledge of the...

Significance Humans have caused extinctions of large-bodied mammalian herbivores over the past ∼100,000 y, leading to cascading changes in ecosystems. Conversely, introductions of herbivores have, in part, numerically compensated for extinction losses. However, the net outcome of the twin anthropogenic forces of extinction and introduction on herbi...

Flying squirrels are the only group of gliding mammals with a remarkable diversity and wide geographical range. However, their evolutionary story is not well known. Thus far, identification of extinct flying squirrels has been exclusively based on dental features, which, contrary to certain postcranial characters, are not unique to them. Therefore,...

Suidae cranial material is very scarce in South Africa. Here we present a newly found partial cranium recovered from the site of Malapa, South Africa. The cranium is dorsoventrally crushed and does not preserve dentition. We reconstruct the cranium using three-dimensional techniques based on more complete material from Eastern Africa. We assign the...

Corral de Lobato, a karstic site in the area of Molina de Aragón has been studied in a preliminary way. Even though there are not many Neogene karstic sites in the Iberian Chain, they occur in four clusters, with ages ranging from latest middle Miocene (MN7/8) to early Pleistocene (MN17). Correlations between these clusters and the reference strati...

Living rhinoceros’ species are but a vestige of the great diversity that the Family Rhinocerotidae attained during the Cenozoic. We present an overview of the diversification patterns of the Rhinocerotina (Family Rhinocerotidae), with emphasis on the potential influence of sampling biases. We conducted a taxonomic review of the group, including an...

A new and phylogenetically basal species of Carpolestes, the youngest and most derived genus of the plesiadapoid family Carpolestidae in North America, is described from a late Tiffanian (Ti-5) site in Sweetwater County, Wyoming, USA. Carpolestids differ from closely related plesiadapoid clades in having an enlarged, multicuspidate, blade-like P4 t...

The dental pattern of Yindirtemys deflexus from Mongolia has been analysed using a Micro-CT scanner. This ctenodactylid exhibits a peculiar dental pattern, characterised by a mesodont dentition with some degree of selenodonty, an intricate enamel folding and elevated connections between cusps. Furthermore, the wear sequence in the upper tooth row s...

Gundis, or comb rats, are rodents of the family Ctenodactylidae. Extant gundis are restricted to Africa and represent a vestige of the diversity that the ctenodactylids attained at both palaeoecological and palaeobiogeographical levels. Here, we present an updated review of the Ctenodactylidae from the Valley of Lakes, Mongolia, based on the study...

We describe cranial, mandibular, and dental remains of five individuals of the giant mustelid Eomellivora piveteaui Ozansoy, 1965, from the late Miocene (MN10) site of Cerro de los Batallones (Madrid, Spain)—the first complete cranial remains recorded for this species and the most complete remains of the genus. This new sample enables a review of t...

As a consequence of the growth of the Antarctic ice-sheet during the middle Miocene, a global decrease of temperatures and an associated increase in aridity provoked several environmental changes all around the world. Such environmental variations can be detected in the continental record of the mammalian prey community structure using a synecologi...

The Ventian land mammal age includes most of the Spanish faunas assigned to the biochronologic unit MN 13. It is correlatable with the Messinian, although it may include, in its latest part, Early Pliocene faunas. We propose that the Ventian begins with the fi rst occurrence of the Muridae genus Stephanomys (7 Ma, paleomagnetic dating from El Bunke...

The exceptional fossil sites of Cerro de los Batallones (Madrid Basin, Spain) contain abundant remains of Late Miocene mammals. From these fossil assemblages, we have inferred diet, resource partitioning and habitat of three sympatric carnivorous mammals based on stable isotopes. The carnivorans include three apex predators: two sabre-toothed cats...

The Ventian land mammal age includes most of the Spanish faunas assigned to the biochronologic unit MN 13. It is correlatable with the Messinian, although it may include, in its latest part, early Pliocene faunas. We propose that the Ventian begins with the first occurrence of the Muridae genus Stephanomys (7 Ma, paleomagnetic dating from El Bunker...

New rhinocerotid remains from the early middle Miocene site of Príncipe Pío-2, Madrid Basin (Madrid, Spain), are described and identified as belonging to Hispanotherium matritense. They constitute the first complete cranial remains recorded for this species, permitting the description of its cranial morphology and updating the species diagnosis. Ne...

This paper included undescribed rhinoceros material from Estrepouy (France) stored in the Université Claude Bernard, Lyon that were previously identified by Antoine et al (2000). The rhinoceros record from Estrepouy is represented by three species: Protaceratherium minutum, `Plesiaceratherium´ platyodon and Diaceratherium aurelianense . En este tr...

The evolution of tyrannosauroids took place through 100 millions of years. They became one of the most ubiquitous groups of carnivorous dinosaurs during the Mesozoic and some of them are among the biggest terrestrial carnivores that have ever existed. Here we apply a maximum likelihood approach in order to reconstruct ancestral biogeographic ranges...

El análisis de elementos finitos (AEF) es un método numérico desarrollado originalmente para simular la respuesta mecánica de fuerzas discretas aplicadas sobre estructuras complejas. Se pretende analizar el papel de los cíngulos anterior y posterior en el proceso de masticación en rinocerontes. Se ha utilizado un modelo 3D simplificado de un molar...

The uses of toxic substances in the animal kingdom are usually explained as adaptations to reach bigger prey—venom, or to defend from the attack of predators—poison. This is a quite simplistic explanation of the reality, which offers other, less evident, uses for the possession of these compounds. In the present work, we analyze the characters of B...

Even though phylogenetic relationships within Rhinocerotidae (Perissodactyla) have been controversial for many years, some taxa have been recently reviewed. One of the best known is the subtribe Elasmotheriina, a specialized group of Neogene rhinoceroses with a widespread distribution throughout Eurasia and Africa. Its paleobiogeographic history is...

Four species of digeneans parasitic in the bogue Boops boops from the Spanish coast of the NE Atlantic are described. All are new records for this host, but one species is new and the other three are considered to be accidental parasites. Wardula bartolii n. sp. (Mesometridae) is distinguished from its two congeners on the basis of a range of morph...