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

<p>The Middle Eocene Climatic Optimum (MECO) represents an episode of widespread&#160;warming occurring ~40 million years ago. It is characterized by gradual warming over&#160;a period of 500,000 years, leading to a rise in ocean temperatures of about 5&#176; C in the&#160;mid and high-latitudes (Sluijs et al., 2013). Contrary to the traditional understanding&#160;and consensus that accommodation space or downstream factors control stratigraphic&#160;architecture in fluvial successions, we test the hypothesis that upstream factors, rather&#160;than downstream factors, control fluvial architecture through changes in the median&#160;grain size, sediment supply and water discharge with paleoslope being a measurable&#160;proxy to quantify these changes. We test our hypothesis utilizing the natural system&#160;of the Escanilla sediment routing system, encompassing the Middle Eocene Climatic&#160;Optimum. The Escanilla system is an overall prograding system, consisting of 1000 m&#160;thick alluvial and fluvial deposits at the southern-margin of the Tremp-Graus Basin in&#160;the south/central Pyrenees, Spain. Multiple lateral measurements for grain size&#160;distributions and cross-set measurements, flow direction and channel geometry are&#160;taken close to the source (Coll de Vent), at an intermediate location (Lascuarre), and&#160;at a distal part (Olson) of the system for paleohydraulic reconstructions. Drone flight&#160;missions are also undertaken to capture aerial photographs of the field area, which&#160;are required for the construction of 3D photogrammetric models. At Olson, alternating sequences of laterally continuous amalgamated channel bodies and several small&#160;sequences of vertically stacked isolated channel bodies have been identified.&#160;Preliminary results show distinct values of median grain size, dune height, flow depth&#160;and paleoslope for the amalgamated and vertically stacked isolated channel&#160;sequences across the MECO; the addition of our 3D models provide further insight&#160;into the lateral connectivity of the amalgamated units. Our results suggest different&#160;paleohydraulic conditions during the deposition of amalgamated and nonamalgamated&#160;units. This data will also be supported by numerical simulations carried&#160;out to better understand the response of fluvial systems to changes in upstream&#160;factors.</p>

Download Full-text

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

MorphoMuseuM ◽

10.18563/journal.m3.94 ◽

2019 ◽

Vol 5 (4) ◽

pp. e94

Author(s):

Mickaël Mourlam ◽

Maëva J Orliac

Keyword(s):

Middle Ear ◽

Ossicular Chain ◽

3D Models ◽

Early Evolution

Download Full-text

An assemblage of giant aquatic snakes (Serpentes, Palaeophiidae) from the Eocene of Togo

Swiss Journal of Palaeontology ◽

10.1186/s13358-021-00236-w ◽

2021 ◽

Vol 140 (1) ◽

Cited By ~ 1

Author(s):

Georgios L. Georgalis ◽

Guillaume Guinot ◽

Koffi Evenyon Kassegne ◽

Yawovi Zikpi Amoudji ◽

Ampah Kodjo C. Johnson ◽

...

Keyword(s):

Middle Eocene ◽

Ct Scanning ◽

3D Models ◽

Late Eocene ◽

Micro Ct ◽

African Species ◽

Western Africa ◽

Eastern Usa ◽

New Material ◽

Tentative Diagnosis

AbstractWe here describe a monospecific assemblage of giant aquatic snakes from the middle Eocene of Kpogamé, Togo. The material, consisting of large isolated vertebrae, is referred to Palaeophis africanus, an enigmatic palaeophiid species, which was so far otherwise known only from a limited number of vertebrae from the middle Eocene of Nigeria and Angola. Material from the late Eocene of the eastern USA that had been referred to the same species, is here instead considered too fragmentary for species-level determination and Palaeophis africanus is thus so far restricted to Africa. With the aid of micro-CT scanning, we present 3D models of 17 vertebrae, pertaining to different portions of the vertebral column. We provide detailed comparisons of the new material with all named African species of the genus Palaeophis. A tentative diagnosis of Palaeophis africanus is provided. With more than 50 vertebrae, the new Togolese specimens represent the most abundant known material attributed to Palaeophis africanus and significantly enhance our knowledge of the vertebral anatomy and intracolumnar variation for this taxon. Furthermore, this adds to the, as yet, extremely scarce fossil record of squamates from central western Africa, a region where Paleogene herpetofaunas are only rather poorly known.

Download Full-text

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

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2021.1439 ◽

2021 ◽

Vol 288 (1960) ◽

Author(s):

Lionel Hautier ◽

Rodolphe Tabuce ◽

Mickaël J. Mourlam ◽

Koffi Evenyon Kassegne ◽

Yawovi Zikpi Amoudji ◽

...

Keyword(s):

Evolutionary History ◽

New Genus ◽

Middle Eocene ◽

Early Evolution ◽

Pivotal Role ◽

Tooth Crown ◽

New Genus And Species ◽

History Of ◽

Lower Molar ◽

Phosphate Deposits

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 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.

Download Full-text