Maeva Orliac

• PhD
• Researcher at Université de Montpellier

Raoellidae are small artiodactyls from the Indian subcontinent closely related to stem cetaceans. They bring crucial information to understand the early phase of the land‐to‐water transition in Cetacea. If they are considered to be partly aquatic, the question of their dietary habits remains partly understood due to their “transitional” morphology....

Introduction Raoellidae are small artiodactyls retrieved from the middle Eocene of Asia (ca - 47 Ma) and closely related to stem Cetacea. Morphological observations of their endocranial structures allow for outlining some of the early steps of the evolutionary history of the cetacean brain. The external features of the brain and associated sinuses...

Phosphate rocks are the most important natural source of phosphorus. While a large literature discusses the conditions of their formation in marine environments, few document their formation in a terrestrial context. The Quercy phosphate mines in south-west France, known as phosphatières, are notable for their exceptional Cenozoic palaeontological...

Raoellid mammals are small artiodactyls from the Eocene of Asia, hypothesized to be closely related to stem Cetacea. Knowledge of the cranial and dental morphology of Raoellidae comes mostly from one species, Indohyus indirae. Here we describe new material of another raoellid genus, Khirtharia, based on material retrieved from the Kalakot area, Jam...

In this work, we digitally restore the snout of the raoellid Khirtharia inflata from the Kalakot area (Rajouri District, Jammu & Kashmir, India). Raoellids are small, semiaquatic ungulates closely related to cetaceans. The specimen is fairly complete and preserves left and right maxillae, left premaxilla, and part of the anterior and jugal dentitio...

Simultaneously investigating the effects of abiotic and biotic factors on diversity dynamics is essential to understand the evolutionary history of clades. The Grande Coupure corresponds to a major faunal turnover at the Eocene–Oligocene transition (EOT) (~34.1 to 33.55 Mya) and is defined in western Europe as an extinction of insular European mam...

Bats are among the most recognizable, numerous, and widespread of all mammals. But much of their fossil record is missing, and bat origins remain poorly understood, as do the relationships of early to modern bats. Here, we describe a new early Eocene bat that helps bridge the gap between archaic stem bats and the hyperdiverse modern bat radiation o...

The present 3D Dataset contains the 3D models of extant Chiropteran endocranial casts, documenting 16 of the 19 extant bat families. They are used by Maugoust & Orliac (2023) to assess the correspondences between the brain and brain-surrounding tissues (i.e., neural tissues, blood vessels, meninges) and their imprint on the braincase, allowing for...

Bats form a diverse group of mammals that are highly specialized in active flight and ultrasound echolocation. These specializations rely on adaptations that reflect on their morphoanatomy and have been tentatively linked to brain morphology and volumetry. Despite their small size and fragility, bat crania and natural braincase casts ("endocasts")...

Since molecular data identified hippopotamids as the closest living relatives of cetaceans, a common aquatic/semiaquatic ancestor hypothesis for these modern taxa has naturally been proposed. However, recent molecular studies concluded that most molecular adaptations in extant cetaceans occurred after their split from hippopotamids. If the question...

Endocranial casts are capable of capturing the general brain form in extinct mammals due to the high fidelity of the endocranial cavity and the brain in this clade. Camelids, the clade including extant camels, llamas, and alpacas, today display high levels of gyrification and brain complexity. The evolutionary history of the camelid brain has been...

This chapter presents a detailed review of works published on Artiodactyla endocasts and provides a comprehensive examination of artiodactyl brain evolutionary history, including Cetacea, from the early Eocene (c.a. 45 Ma) onwards. Artiodactyl endocasts have been studied from the second half of the nineteenth century to the 1970s. These works on na...

Cet article dcrit les rongeurs de la nouvelle faune de Cos (Tarn-et-Garonne, Quercy, France) dont l'tude des primates vient d'te acheve (Godinot et al. 2021). Parmi ces rongeurs, peu diversifis, l'espce la plus petite est attribue Eogliravus wildi Hartenberger, 1971. Toutes les espces d'Eogliravus Hartenberger, 1971 sont ici redcrites et leurs diag...

Endothermy underpins the ecological dominance of mammals and birds in diverse environmental settings1,2. However, it is unclear when this crucial feature emerged during mammalian evolutionary history, as most of the fossil evidence is ambiguous3–17. Here we show that this key evolutionary transition can be investigated using the morphology of the e...

Domestication has led to many changes in domestic animal biology, including their anatomy. The shape of the inner ear, part of the mammalian ear, has been found particularly relevant for discriminating domesticated species, their hybrids or differentiating the wild and domestic populations of a single species. Here we assessed the use of the size a...

Our knowledge of the external brain morphology of the late Eocene artiodactyl ungulate Mixtotherium, relies on a plaster model realized on a specimen from the Victor Brun Museum in Montauban (France) and described by Dechaseaux (1973). Here, based on micro CT-scan data, we virtually reconstruct the 3D cast of the empty cavity of the partial cranium...

The "phosphatières du Quercy" are karstic fillings exploited for phosphate at the end of the 19th century. They yield countless continental fossils through some 30 million years, ranging from late early Eocene to early Miocene. This exceptional paleontological series documents the 'Grande Coupure', a major biogeographical event involving a profound...

Africa has played a pivotal role in the evolution of early proboscideans (elephants and their extinct relatives), yet vast temporal and geographical zones remain uncharted on the continent. A long hiatus encompassing most of the Eocene (Ypresian to the Early Priabonian, around 13 Myr timespan) considerably hampers our understanding of the early evo...

The Eocene--Oligocene transition (EOT) represents a period of global environmental changes particularly marked in Europe and coincides with a dramatic biotic turnover. Here, using an exceptional fossil preservation, we document and analyse the diversity dynamics of a mammal clade, Cainotherioidea (Artiodactyla), that survived the EOT and radiated r...

Bat fossil endocasts have been little studied in the literature (nine published works, only one in the XXIth century), and macromorphology of the brain of extant bats has only been characterized at the family-level. We describe here in detail the endocranial casts of four fossil hipposiderid species based on μCT-scans data and propose a revised nom...

A correction to this paper has been published: https://doi.org/10.1007/s10914-021-09554-9

The Eocene-Oligocene transition (EOT) represents a period of global environmental changes particularly marked in Europe and coincides with a dramatic biotic turnover. Here, using an exceptional fossil preservation, we document and analyse the diversity dynamics of a mammal clade, Cai-notherioidea (Artiodactyla), that survived the EOT and radiated r...

Endothermy (“warm-bloodedness”) underpins the ecological dominance of mammals and birds in diverse environmental settings1-3. However, it is unclear when this crucial feature emerged during mammalian evolutionary history, as most fossil evidence is ambiguous4-25. Here, we show that new information on this key evolutionary transition can be obtained...

The present 3D Dataset contains the 3D models of the endocranial cast of two specimens of Indohyus indirae described in the article entitled “The endocranial cast of Indohyus (Artiodactyla, Raoellidae): the origin of the cetacean brain” (Orliac and Thewissen, 2021). They represent the cast of the main cavity of the braincase as well as associated i...

(300 mots) We present the first description of the endocranial cast of the small raoellid artiodactyl Indohyus indirae. Raoellidae are sister group to Cetacea and the new morphological observations allow for outlining some of the early steps of the evolutionary history of the cetacean brain. The combination of primitive artiodactyl features and typ...

A new artiodactyl of moderate size, Rajouria gunnelli nov. gen., nov. sp., is described on the basis of several dentaries, maxillae and isolated teeth from the middle Eocene Subathu Group of the Kalakot area, Rajouri District, Jammu and Kashmir, India. Despite its general resemblance with the family Dichobunidae by the retention of a paraconid on m...

The Oligocene Malembo locality, Cabinda exclave, Angola, has yielded a rich vertebrate fauna represented by fragmentary remains. This fossiliferous locality is the only definite occurrence of Oligocene terrestrial mammals in sub-Saharan West Africa. The hyracoids from Malembo have only been very succinctly described and compared thus far, so that t...

Teeth are frequently used in phylogeny in order to better characterize the evolution of extinct mammal species. While most studies have focused on the adult dentition, the consideration of characters from the deciduous dentition could also contribute to reinforce phylogenetic assumptions or disentangle phylogenetic issues. We chose to investigate t...

Thanks to the exceptional abundance of Quercy fossil record of cainotherioids (more than 900 occurences), we inferred the diversification history of cainotherioids using a birth–death model with a constrained shift of 1 Myrs.

Cainotheriidae are small artiodactyls restricted to Western Europe deposits from the late Eocene to the middle Miocene. From their first occurrence in the fossil record, cainotheriids show a highly derived molar morphology compared to other endemic European artiodactyls, called the “Cainotherium plan”, and the modalities of the emergence of this fa...

This contribution includes the 3D models of the reconstructed ossicular chain of the cainotheriid Caenomeryx filholi from the late Oligocene locality of Pech Desse (MP28, Quercy, France) described and figured in the publication of Assemat et al. (2020). It represents the oldest ossicular chain reconstruction for a Paleogene terrestrial artiodactyl...

This work describes an unparalleled sample of isolated fossil auditory ossicles of cainotheriid artiodactyls from the Paleogene karstic infillings of Dams (Tarn-et-Garonne, Quercy, France). This collection comprises a total of 18 mallei, 28 incudes and three stapedes. It allows the documentation of both intra- and interspecific variability of ossic...

In this contribution, we describe the external and internal morphology of a delphinid petrosal bone collected from Ahu Tahai, a burial site located on the Southwestern coast of Easter Island, at Hangaroa. We discuss the taxonomic attribution of this archaeological item and describe its internal structures based on μCT data, including the bony labyr...

Modifications of the morphology and acoustic properties of the ossicular chain are among the major changes that accompanied the adaptation of Cetacea to the aquatic environment. Thus, data on the middle ear ossicles of early whales are crucial clues to understand the first steps of the emblematic terrestrial/aquatic transition that occurred in that...

This contribution contains the 3D models of the ossicles of a protocetid archaeocete from the locality of Kpogam´ e, Togo, described and figured in the publication of Mourlam and Orliac (2019).

A new artiodactyl of moderate size is described on the basis of several dentaries and maxillae from the middle Eocene Subathu Group of the Kalakot area, Rajouri District, Jammu and Kashmir, India. Despite its general resemblance with the family Dichobunidae this taxon shares with Raoellidae two unambiguous characters: the presence of a hypoconulid...

Cainotheriids are a family of small artiodactyls, known in the fossil record from the late Eocene to the middle Miocene in Western Europe. Contrary to several European endemic ungulate groups that became extinct at the end of the Eocene or close to the Eocene–Oligocene transition (Grande Coupure), cainotheriids crossed this boundary and diversified...

Bats have some of the most spectacular morpho-anatomical modifications of mammals. They notably present modifications of their perception organs and of sensory integration in relation with the physical constraints of the aerial environment. Several studies focused on the onset of echolocation in bats and on the evolution of brain characteristics in...

We provide morphological, quantitative, and qualitative studies of cranial endocasts of mesotheriid notoungulates solving previous open debate on notoungulate endocasts. For that purpose, we use the most accurate digital reconstructions methods. We confirm that mesotheriids have endocasts similar in shape and gyrification to those of other rodentli...

Studying ontogeny in both extant and extinct species can unravel the mechanisms underlying mammal diversification and specialization. Among mammalian clades, Cetartiodactyla encompass species with a wide range of adaptations, and ontogenetic evidence could clarify longstanding debates on the origins of modern specialized families. Here, we study th...

Artiodactyls, or even-toed ungulates, encompass a noteworthy diversity of mammals today represented by pigs, ruminants, hippopotamuses, camels and cetaceans. They have a long evolutionary history that goes back to the earliest Eocene (ca. 56 Ma) in Eurasia and North America. In Europe, during the middle and late Eocene (ca. 48 to 34 Ma) artiodactyl...

Diacodexeidae are the first representatives of Artiodactyla in the fossil record. Their first occurrence is at the very base of the Ypresian (earliest Eocene, 56.0 Ma) with Diacodexis, a genus well diversified during the early Eocene in Europe, especially during the MP7–MP8 + 9 interval. However, most of European species are documented by scarce ma...

Figure 1, online Resource 3: Linear measurements taken from digital cranial endocast (Mesotherium maendrum; MACN PV 2925) and from skulls (Mesotherium maendrum; MACN PV 2925), used to estimate body mass (BM) according the algorithm 4.1 of Mendoza et al. (2006). a, endocast and skull in dorsal view; b, in lateral view; and c, un ventral view, showin...

Temporal relationship of the neocortical quotient and piriform quotient of the family Mesotheriidae. Paleozoic-Cenozioc encephalization quotient comparison in the Notoungulata order and the relations according 1) distinct level of predation presure environments and 2) different families lifestyle.

Figure 1. Online Resource 4. Endocasts and skulls of badly preserved (a-c) specimens or duplicated taxa (d), included in the study but not illustrated in the main document. (Trachytheriines are showed in blue and with *). Figure 2. Online Resource 4. Endocast within the skull of Trachytherus alloxus (MNHN Bol V 6335, holotype). a, dorsal view. b, r...

Table 1. Online Resource 2. Encephalization quotient (EQ): EQ1 (Jerison 1973), or EQ2 (Eisenberg 1981) of the taxa including in this study, using distinct body mass (BM) estimates, of previous endocast studies. Source of data: (a) Jerison (1971); (b) Jerison (1973); (c) Radinsky (1981); (d) Anderson et al. (1985); (e) Damuth, (1990); (f) Roth (1990...

The morphology of the semicircular canal (SC) system is expected to be finely tuned with animal behavior. Using computed tomography data, we compiled a morphological dataset of dicynodont (n=18) and mammalian (n=54) bony labyrinths and found that dicynodonts have significantly higher eccentricity of the vertical SCs than mammals. Biomechanical mode...

Mysticeti (baleen whales) and Odontoceti (toothed whales) today greatly differ in their hearing abilities: Mysticeti are presumed to be sensitive to infrasonic noises [1, 2, 3], whereas Odontoceti are sensitive to ultrasonic sounds [4, 5, 6]. Two competing hypotheses exist regarding the attainment of hearing abilities in modern whales: ancestral lo...

This contribution contains the 3D models described and figured in the following publication: Mourlam, M. J., Orliac, M. J. (2017), Protocetid (Cetacea, Artiodactyla) bullae and petrosals from the Middle Eocene locality of Kpogam´ e, Togo: new insights into the early history of cetacean hearing. Journal of Systematic Palaeontology https://doi.org/10...

Extant cetaceans are fully aquatic mammals with deep modifications of their sensory organs, notably of the sound perception pathway. Early diverging cetaceans, known as archaeocetes, show a diversity of morphologies of the petrotympanic complex and middle ear ossicles, documenting a variety of sound transmission mechanisms from a mostly terrestrial...

Anoplotheriinae are Paleogene European artiodactyls that present a unique postcranial morphology with a tridactyl autopodium and uncommon limb orientation. This peculiar morphology led to various hypotheses regarding anoplotheriine locomotion from semiaquatic to partly arboreal or partly bipedal. The petrosal bone, housing the organs of balance, an...

Caviomorph rodents represent one of the most successful groups of placental mammals from South America. Despite their modern, Neogene and late Paleogene high diversity, their early evolutionary history has long remained obscure. Recent field expeditions in Peruvian Amazonia have yielded among the earliest representatives of that group, in deposits...

Over the past two decades, the development of methods for visualizing and analysing specimens digitally, in three and even four dimensions, has transformed the study of living and fossil organisms. However, the initial promise that the widespread application of such methods would facilitate access to the underlying digital data has not been fully a...