We describe new macro- and microfossils recovered on a field expedition to the North Quarry of Poponguine, a locality in western Senegal that spans the Late Cretaceous through the Early Paleogene, albeit with a likely unconformity at the base of the Danian. Newly discovered macrovertebrates from the Maastrichtian Cap de Naze Formation include pycnodonts, dyrosaurids, and chelonians, the latter two the oldest and first Cretaceous representatives of these clades from Senegal. Screenwashing of this deposit revealed that the matrix also consists of abundant microscopic biological clasts comprising osteichthyan vertebrae, spines, and cranial fragments, shark dermal denticles, invertebrates, and numerous ovoid coprolites among other fragments. These microfossils document a much less conspicuous portion of the paleobiodiversity. We describe the stratigraphy of this new locality and incorporate it into a new correlated section that ties together three other Late Cretaceous-Early Paleogene fossiliferous localities of the Senegalese-Mauritanian Basin. The presence of fossiliferous Danian rocks, which are notably rare in West Africa, is elucidated in our section, which synthesizes prior geological and paleontological work around Poponguine and in the nearby coastal region of Ndayane. Primarily dated using the biostratigraphy of ostracods and foraminiferans, the correlated rock units include the Paki and the Cap de Naze Formations of the Late Cretaceous Diass Group and the Ndayane and the Poponguine Formations of the Paleocene Cap-Vert Group, deposits that capture ancient near shore marine environments. The localities described, although separated by only a few kilometers, exhibit dramatic differences in thickness across faulted blocks of the Diass Horst. Dyrosaurids, which are common fossils in nearshore marine outcrops of West Africa, have been hypothesized to be of African origin and to have dispersed to South America in the Late Cretaceous. This dyrosaurid specimen, although fragmentary, documents a western extreme in the geographic range of African dyrosaurids where the clade would have been well situated for broader trans-Atlantic dispersal.

During this research work we developed another approach to digital mapping using the pixelation technic. This unprecedented digital mapping of the basin MSGBC in Senegal required the compilation of numerous geological data consisting of seismic lines and oil and hydraulic log reports. These spatial reference data include geological information from the surface to the top of the Campanian. The mapped terrains are composed of the Post-Paleocene Complex (PPC), the Paleocene, the Maastrichtian, and the Campanian. The nearest neighbor method has been used to establish the spatial distribution of the different geological formations. Histograms of values were used to determine the confidence intervals of the mapping. They were used to locate areas of low relative error and to apply the 3D digital mapping technique. For instance, Diender Guedj has been mapped at 1:25,000. The result of this mapping is extracted and processed using the DBMS (MySQL) software. The latter allowed both to determine Paleocene gab and update data. And then the database is processed. The programming languages PHP and Javascript have been used to simulate a website.

This study is part of a wide multidisciplinary research program initiated in Senegal for the promotion of geodiversity and is the continuation of previous works carried out in the Dind??f??lo Community Nature Reserve. It aims to strengthen the Senegalese states??? proposal for Lac Rose to acquire the status of UNESCO World Heritage Site, Biosphere Reserve and Ramsar site. To evaluate the geosite, we tried to take into account the concerns of the quantitative site evaluation method according to Brilha (2016). The Lac Rose is located about 30 km NE of Dakar and is characterized by its salty waters containing the green halophilic alga Dunaliella salina, which is responsible for its pink coloration. Its bottom is a thin saline crust on top of a mud rich in foraminifera, ostracods and diatoms, which study has enabled to reconstruct its history. Around the Lac Rose, several ecosystems have been described (ponds, dunes, lakeshore fringe), whose conservation depends on the conservation of the lake that faces threats due to lack of water and salt supply along with the backfilling of the depression. Our proposal is based on four among ten criteria proposed by UNESCO for the World Heritage Convention implementation: criterion 8 verified by the historical reconstruction of the lake; criterion 5 justified by the extraction of salt, shells and dune sand; criterion 7 justified by the pink coloration of the lake waters and criterion 9 justified by the development of Dunaliella salina. Ultimately, this work will pave the way for implementing of UNESCO World Heritage Site and will support the State of Senegal in its program to set up a geopark in the Dakar region.

La présente étude s’inscrit dans un vaste programme de recherche multidisciplinaire entamé au Sénégal pour la promotion de la géodiversité et fait suite aux travaux réalisés dans la Réserve Naturelle Communautaire de Dindéfélo. Elle vise à renforcer la proposition de l’état du Sénégal pour que le Lac Rose acquière le statut de patrimoine mondial de l’UNESCO, de Réserve de Biosphère et de site Ramsar. Pour évaluer le géosites, nous avons essayé de prendre en compte les préoccupations de la méthode d'évaluation quantitative des sites selon Brilha (2016). Le Lac Rose est situé à 30 km environ au NE de Dakar et se caractérise par ses eaux sursalées renfermant l’algue verte halophile Dunaliella salina, responsable de sa coloration rose. Son fond est tapissé d’une mince croûte saline surmontant une vase riche en foraminifères, ostracodes et diatomées dont l’étude a permis de reconstituer son histoire. Autour du Lac Rose, plusieurs écosystèmes ont été décrits : les étangs, les dunes, la frange bordière du lac, dont la survie dépend de celle du lac menacé par un arrêt de l’alimentation en eau et sel et un comblement de la dépression. Notre proposition s’appuie sur quatre critères parmi les dix proposés par l’UNESCO pour la mise en œuvre de la Convention du patrimoine mondial : le critère 8 vérifié par la reconstitution de l’histoire du lac ; le critère 5 justifié par l’exploitation du sel, des coquillages et du sable dunaire ; le critère 7 justifié par la coloration rose des eaux du lac et le critère 9 par le développement de Dunaliella salina. À terme, ce travail permettra de créer les prémices d’un Patrimoine Mondiale de l’Unesco et accompagner l’état du Sénégal dans son programme de mise en place d’un géoparc dans la région de Dakar.

A stratigraphic, palaeontological and sedimentological study was carried out in the red beds cropping out on the left side of Oued Tafarahit, south-east of the Ksour Mountains (Algeria). The studied succession consists of a non-marine fining-upward detrital formation, including microconglomerate, sandstone and clay beds, which were previously attributed to the Cenozoic sensu lato, since no palaeontological evidence was available. Sedimentology suggests deposition in a fluvial environment. The clayey levels yielded the assemblage formed by the charophytes Peckichara atlasensis, Maedleriella cristellata, Nitellopsis (Tectochara) thaleri, Grovesichara sp., and Lamprothamnium papulosum and the ostracods Neocyprideis meguerchiensis, Herpetocypris? sp. and Cyprinotus? sp. This assemblage allows constraining the age of the detrital series from Oued Tafarahit to the Ypresian. Ostracods are typical of freshwater to euryhaline environments. The freshwater taxa (Herpetocypris? sp. and Cyprinotus? sp.) would indicate phases of desalinisation during periods of flood. However, the brackish water species (Neocyprideis meguerchiensis) is characteristic of saline phases related to low water table periods. Moreover the charophyte and ostracod assemblage confirms a close palaeobiogeographic relationship between North Africa and Southern Europe during the Lower Eocene. 2020 Elsevier Masson SAS. All rights reserved.

Following our fieldwork in Paleogene deposits of Togo, we herein report cranial as well as postcranial elements belonging to the family Dyrosauridae. This assemblage is dated to the Late Paleocene (Thanetian) from two quarries in southern Togo. The specimens include a partial skull presenting two large supratemporal fossae and a massive occipital condyle; long and slender isolated teeth; amphicoelous vertebrae including several articulated ones; and two osteoderms devoid of carina. The morphology of the partial skull reveals similarities with some African longirostrine forms such as Rhabdognathus spp., although this attribution cannot be confirmed. Longirostrine forms, known in the late Paleocene and early Eocene of the Iullemmeden basin (Nigeria, Niger, Mali, Algeria) and in the phosphates of Morocco and Tunisia, is only represented in Thanetian levels in Togo. Different palaeoenvironmental settings seem to have characterized the various African basins during the lower Eocene, with consequences for the geographic distribution of dyrosaurids. These dyrosaurid remains confirm the presence of the family in Togo during the Paleocene and underline the fossiliferous potential of the coastal sedimentary basin in Togo and in the bay of Benin. (C) 2021 Elsevier Masson SAS. All rights reserved.

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Dans la partie sud-est des Monts des Ksour (Algérie), une étude stratigraphique, paléontologique et sédimentologique a été effectuée sur les couches rouges qui affleurent sur la rive gauche de l’Oued Tafarahit. Il s’agit d’une série continentale détritique granodécroissante composée de microconglomérats, de grès et d’argiles attribuées au Cénozoïque sans preuve paléontologique. Les niveaux argileux ont livré des charophytes [Peckichara atlasensis, Maedleriella cristellata, Nitellopsis (Tectochara) thaleri, Grovesichara sp. et Lamprothamnium papulosum] et des ostracodes (Neocyprideis meguerchiensis, Cyprinotus? sp et Herpetocypris? sp). Cette flore et cette faune permettent d’assigner la Formation Détritique de l’Oued Tafarahit à l’Yprésien inférieur et de confirmer l’existence d’une relation paléobiogéographique étroite entre l’Afrique du Nord et l’Europe du Sud pendant l’Éocène inférieur. La sédimentologie et les microfossiles suggèrent un dépôt dans un environnement fluviatile. Les ostracodes sont typiques des milieux dulçaquicoles à euryhalins. Les formes dulçaquicoles (Cyprinotus? sp. et Herpetocypris? sp.) correspondent probablement à des phases de dessalure lors des périodes de crue. En revanche, l’espèce d’eau saumâtre (Neocyprideis meguerchiensis) est caractéristique des phases de salure lors des périodes d’étiage.

Early Pliocene hominin evolutionary scenarios proposed to date mostly rely on paleontological investigations from eastern Africa. Filling major geographical gaps in the fossil record could potentially invalidate these scenarios and stimulate development of improved theories. Based on published literature, no Pliocene fossil of continental vertebrates have been discovered in Western Africa and the situation is only slightly better in central and northern Africa. Here, we expand the Pliocene vertebrate continental fossil record to western Africa with the description of the Tobene fauna, a new fossiliferous Neogene locality from Senegal. We describe a diversity of large mammals, including at least ten taxa based on fragmentary remains recovered from alluvial channel deposits. Estimation based on weathering events and biochronology suggests an early Pliocene age. Most of these mammalian taxa were widely distributed over the African continent during the early Pliocene. Possible faunal correlations with eastern African localities call for continent-wide paleontological investigations.*************** (c) 2021 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.

Cetaceans constitute a textbook example of the secondary adaptation of tetrapods to aquatic life. This major event in the evolutionary history of mammals is often linked in the literature to the limb‐to‐fin transition. Paradoxically, limb bones are scarce in the fossil record of early cetaceans, and the transition from a limb‐adapted morphology for an amphibious life in shallow water to a fin‐adapted morphology for a pelagic lifestyle remains poorly documented. Here, we describe new protocetid remains from the upper Lutetian of Senegal, including a nearly complete articulated forelimb. A cladistic analysis including 24 taxa and 137 morphological characters recovers the new African specimen close to Carolinacetus. It also confirms that cetacean dispersal to the New World was not the result of a single colonization event. A 3D model of the forelimb was reconstructed. Anatomical comparisons suggest that it is unlikely that the Senegalese forelimb was used as a rigid pectoral flipper for steering as in basilosaurids and modern cetaceans. Instead, we suggest that the hand was actively used during swimming. This challenges previous reconstructions of protocetids as mainly foot‐powered swimmers, and suggests that swimming specializations of early cetaceans were probably more diverse than previously considered.

A long hiatus encompassing most of the Eocene (end of the Ypresian to the early Priabonian) breaks up the proboscidean evolutionary history, which is otherwise documented by a rich fossil record. Only two post-Ypresian localities from West Africa (Mali and Senegal) have yielded scarce Moeritherium-like dental remains. Here, we study one of these remains from Senegal and name a new genus and species, Saloumia gorodiskii. This taxon, confidently mid-Lutetian in age, evokes Moeritherium and elephantiforms with its wrinkled enamel, lack of centrocrista, and strong lingual cingulum. However, due to its pronounced bunodonty, which departs from the bunolophodonty of both Moeritherium and elephantiforms, we cannot exclude the possibility that Saloumia documents an early experiment in dental diversity among Paleocene-Eocene proboscideans, without direct relationships with later proboscideans. UUID: http://www.zoobank.org/0b6b83f8-817d-498c-a672-8ffa8f81a978

We report here three new elasmobranch fossil taxa from Thanetian-Lower Lutetian nearshore marine deposits of northeastern (Matam region) and central-western (Sine-Saloum region) Senegal. These three new taxa represent the oldest species of the enigmatical elasmobranch Odontorhytis, the oldest putative representatives of marine potamotrygonid, and an uncertain dasyatoid genus with the smallest grinding dentition ever described. These new taxa, representing the second Cenozoic elasmobranch remains formally described from Senegal, broaden our understanding of their evolutionary and biogeographic history in the equatorial Eastern Atlantic during this time period. Their occurrences confirm hypothesised stratigraphically correlations between the top of Matam Fm. and the base of Lam Lam Fm., refine the marine connections between these two Senegalese regions, and suggest that these genera were broadly distributed within the shallow marine settings of the equatorial Eastern Atlantic during latest Paleocene-early Middle Eocene. (C) 2020 Elsevier Masson SAS. All rights reserved.

Bulk sampling and surface collecting of two glauconitic horizons located in Southern Togo yielded a diverse elasmobranch fauna described here. This fauna includes 30 species dominated by carcharhiniforms (eleven species), myliobatiforms (nine species) and lamniforms (five species); it also comprises three orectolobiforms, whereas the squatiniforms and rhinopristiforms are represented by one species each. Although the poor preservation of the specimens hampered numerous species-level identifications, the vast majority of taxa identified were formerly reported from the Paleocene–Ypresian interval, four of which being exclusively known from the upper Paleocene. This, along with the six associated benthic foraminifera species, indicates a late Thanetian age for the sampled horizons and provide age constraints on a geographically widespread benchmark horizon in Western Africa. The composition of the elasmobranch assemblage shows strong resemblances with upper Paleocene faunas from Morocco and differs markedly from known assemblages from geographically closer localities in Niger and Nigeria, which suggests strong palaeoenvironmental control on the distribution of Thanetian elasmobranch diversity.

The upper Cretaceous of the eastern part of the Ksour Mountains (Western Saharan Atlas, Algeria) is classically subdivided into three fossiliferous lithostratigraphic formations: El Rhelida (lower Cenomanian), Mdaouer (lower-middle Cenomanian) and Rhoundjaia (upper Cenomanian-lower Turonian).The western part of the Ksour Mountains, which is less documented and poorly known, is here the subject of a detailed sedimentological and palaeontological study. Near Hassi Djeifa locality (Forthassa) the upper Cretaceous is represented by the upper part of Mdaouer Formation and by the lowermost part of Rhoundjaia Formation. The deposits attributed to the Mdaouer Formation are composed of reddish or green marlstone intercalated by biolaminated limestone, bioclastic limestone with gastropods and bivalves, and sand-stone. The selachians (Mafdetia tibniensis, Baharipristis bastetiae), pycnodontiform fishes, and ostracod fauna (Damonella spp., Ilyocypris? sp., Cypridea sp., Paracypria? sp.) coming from manly beds are studied in detail. The two selachian species (Order of Rajiformes) were so far restricted to the Early Cenomanian of Egypt. Our sedimentological and palaeontological data support a probable Early Cenomanian age of the studied deposits and indicate a coastal plain palaeoenvironment continually influenced by the action of tide. (C) 2019 Elsevier Masson SAS. All rights reserved.

On the northern coast of the Cape Verde peninsula, Lake Retba is one of the few depressions that have preserved its water body due to the drought that plagued the Sahel in the 1960s.The aim of this article is to understand the resilience of the lake to the drought.For this purpose, a deep knowledge of interactions between the different components of the hydro-system, namely: lake, dune tablecloth, ponds and ocean is necessary.The use of electrical resistivity tomography (ETR) and chemical and isotopic tools yielded conclusive results.Electrical tomography of resistivity (ETR) shows throughout the coastal dune a superposition between fresh and salt water, with even a predominance of salt water at the level of the old canal.The chemistry of the major ions and isotopes confirms this contact between the saltwater bison of the sea and the lake by showing a superposition of the fresh/brackish waters on the salty waters of the bevel, which, in turn, are found in the very salty waters influenced by the lake.This translates a feeding of the lake by the sea through the bevel.At the canal level, this feeding is done, on the surface, by means of ponds whose water characteristics show that they constitute an outcrop of the bevel.The freshwater body of the coastal dune that floats on salt water in the form of a lens also flows into the lake.The feeding of the lake, by the sea through the bevel and the ponds, and by the water table, is therefore effective and attested by all the methods used in this work.It allowed the resilience of the lake against the drought.This inflow of seawater into the lake is at the origin of its salinization and

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We describe a partial dyrosaurid skeleton recently prepared out of a limestone block discovered in the 1930s from Danian strata along the Atlantic coast of Senegal. The specimen, from a single individual, comprises nicely preserved elements of the appendicular and axial skeleton from the abdominal and sacral region, which enables us to refine our knowledge on some postcranial characteristics of the Dyrosauridae. Although Dyrosauridae are abundant in early Eocene deposits of North Africa, the present discovery in the Danian of Senegal fills a patchier record early after the K/Pg boundary and provides an important comparative data point with the few other Danian dyrosaurid records such as Atlantosuchus from nearby Morocco or Guarinisuchus and Hyposaurus from Brazil and the USA, respectively.

The phosphate series of Matam (located at the North-East of Senegal) consists of a 10 meters alternation of soft phosphate levels, sand horizons and phosphatic limestones. While they were only mentioned in some preliminary geological works, isolated teeth of selachians are nevertheless common in these phosphate deposits. Detailed fieldwork of 9 new well-drillings allowed us to establish the first exhaustive list of the Matam selachian fauna with their biostratigraphical distribution through five main fossiliferous levels spanning the Thanetian-Early Lutetian period. Their importance for biochronological, paleoenvironmental purposes and correlations with the other Eocene phosphate deposits worldwide is noteworthy. The Matam selachian is represented by 38 species belonging to 34 genera, 16 families and 6 orders, which allow us to define different biochronological associations. The first association (e.g. characterized by Eotorpedo hilgendorfi and E. jaekeli) is associated with the sands of the top of Gorgol Fm. that constitute the ground level of exploited phosphate deposits and testify of a clear marine influence during the Late Thanetian. The three following associations were recovered in the main levels of exploited phosphate of the Matam Fm. They contain a richer and more diversified fauna dated to ?Lower Ypresian and are characteristic of neritic environments too. The last association (top of the Matam Fm.) overlies the phosphate layers and is characterized by a drastic decrease in selachian richness and diversity. Dated to the Lower Lutetian, this last faunal association may be indicative of a marine embayment in Matam area and contrary to western Senegal where phosphate deposits begin. If all these associations appear typical of the eastern margins of central Atlantic, the light observed faunal turnover across the ten-meter sequence suggests productivity changes in phosphate depositions during the Late Thanetian-Early Lutetian period.