3D models related to the publication: Early Evolution of the Ossicular Chain in Cetacea: Into the Middle Ear Gears of a Semi-Aquatic Protocetid Whale

International audienceThis contribution contains the 3D models of the ossicles of a protocetid archaeocete from the locality of Kpogamé, Togo, described and figured in the publication of Mourlam and Orliac (2019)

Mourlam & Orliac_Ossicles Protocetid_ESM_Document S1

Content Text S1. Incudomallear complex orientation; Text S2. Chorda tympani hypothetical pathway; Figure S1. Spatial “incudomallear-centred” referential; Figure S2. Bone thickness maps of UM-KPG-M 73; Figure S3. Tympanic membrane area estimation; Figure S4. Stapes - Comparative plate; Figure S5. Incus - Comparative plate; Figure S6. Malleus reconstruction and comparison; Figure S7. Chorda tympani location; Figure S8. Malleus - Comparative plate; Figure S9. Middle ear’s functional profile comparison

3D models related to the publication: Early Evolution of the Ossicular Chain in Cetacea: Into the Middle Ear Gears of a Semi-Aquatic Protocetid Whale

International audienceThis contribution contains the 3D models of the ossicles of a protocetid archaeocete from the locality of Kpogamé, Togo, described and figured in the publication of Mourlam and Orliac (2019)

Infrasonic and Ultrasonic Hearing Evolved after the Emergence of Modern Whales

International audienceMysticeti (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 low-frequency sensitivity [7, 8, 9, 10, 11, 12, 13] or ancestral high-frequency sensitivity [14, 15]. The significance of these evolutionary scenarios is limited by the undersampling of both early-diverging cetaceans (archaeocetes) and terrestrial hoofed relatives of cetaceans (non-cetacean artiodactyls). Here, we document for the first time the bony labyrinth, the hollow cavity housing the hearing organ, of two species of protocetid whales from Lutetian deposits (ca. 46–43 Ma) of Kpogamé, Togo. These archaeocete cetaceans, which are transitional between terrestrial and aquatic forms, prove to be a key for determining the hearing abilities of early whales. We propose a new evolutionary picture for the early stages of this history, based on qualitative and quantitative studies of the cochlear morphology of an unparalleled sample of extant and extinct land artiodactyls and cetaceans. Contrary to the hypothesis that archaeocetes have been more sensitive to high-frequency sounds than their terrestrial ancestors [15], we demonstrate that early cetaceans presented a cochlear functional pattern close to that of their terrestrial relatives, and that specialization for infrasonic or ultrasonic hearing in Mysticeti or Odontoceti, respectively, instead only occurred in fully aquatic whales, after the emergence of Neoceti (Mysticeti+Odontoceti)

Evolution of semiaquatic habits in hippos and their extinct relatives: insights from the ear region

International audienceAbstract 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 of aquatic affinities of the first cetaceans has been investigated at large, it has not been the case for the forebears of hippopotamids. Sensory organs are drastically affected by underwater perception. In this work, we question the aquatic affinities of fossil hippopotamoids through an investigation of the morphology and morphometrics of the petrosal bone and cochlea of 12 extinct hippopotamoid taxa. Petrosal and bony labyrinth morphological characters constitute a source of structured phylogenetic signal, both supporting major hippopotamoid clades and bringing original relationships. The morphometric study of functional measurements of the cochlear canal shows that anthracotheres bridge the morphological gap between terrestrial artiodactyls and modern hippopotamids. The integrated functional signal of the ear region further supports convergent acquisitions of semiaquatic behaviour in hippopotamids and cetaceans and indicates that terrestrial hearing was an ancestral trait among Hippopotamoidea. We highlight multiple convergent acquisitions of semiaquatic traits in the ear region of hippopotamoids and new robust phylogenetic characters

La chaîne des osselets de l’oreille moyenne des Cainotheriidae (Mammalia, Artiodactyla)

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3D models related to the publication: First partial cranium of Togocetus from Kpogamé (Togo) and the protocetid diversity in the Togolese phosphate basin

International audience3D model of a Togocetus skull (Protocetidae, Cetartiodactyla)-2/3 Figure 1. 3D reconstruction of the cranium and teeth of ULDG-KPO1. A, lateral view of the left side of ULDG-KPO1; B, palatine view. Abbreviations: C, canine; iof, infraorbital foramen; M, molar; P, premolar. The cranium elements are in grey, canine in dark red, premolar in light red and molar in yellow. Scale bar represents 2 cm

TITLE: First partial cranium of Togocetus from Kpogamé (Togo) and the protocetid diversity in the Togolese phosphate basin. TITRE : Premier crâne partiel de Togocetus de Kpogamé (Togo) et la diversité des protocètes dans le bassin phosphaté togolais

International audiencede cette analyse que le clade incluant le nouveau spécimen et Togocetus représente un embranchement basal au sein des protocètes. L'analyse phylogénétique incluant l'ensemble des restes de protocètes de Kpogamé confirme la diversité singulière du bassin phosphaté togolais, et permet d'examiner des connexions potentielles entre cette faune de protocètes du Togo et les faunes d'autres bassins contemporains d'Afrique

3D models related to the publication: New middle Eocene proboscidean from Togo illuminates the early evolution of the elephantiform-like dental pattern

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New Middle Eocene proboscidean from Togo illuminates the early evolution of the elephantiform-like dental pattern

International audienceAfrica 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 evolutionary history of the group. It is notably the case with the origin of its most successful members, the Elephantiformes, i.e. all elephant-like proboscideans most closely related to modern elephants. Here, we describe a proboscidean lower molar discovered in Lutetian phosphate deposits from Togo, and name a new genus and species, Dagbatitherium tassyi. We show that Dagbatitherium displays several elephantiform dental characteristics such as a three-layered Schmelzmuster, the presence of a mesoconid, transversely enlarged buccal cusps and the individualization of a third lophid closely appressed to a minute distal cingulid. Dagbatitherium represents a stem Elephantiformes, pushing back the origin of the group by about 10 Myr, i.e. a third of its currently known evolutionary history. More importantly, Dagbatitherium potentially unlocks the puzzle of the origin of the unique elephantiform tooth crown organization by bridging a critical temporal and morphological gap between early bunodont incipiently bilophodont proboscidean taxa and more derived elephantiforms