Here we review the fossil record of European mesonychids, which are known only through the genera Dissacus and Pachyaena from Thanetian and Ypresian localities (from MP6 to MP10 reference-levels). We describe two new species, Dissacus rougierae, sp. nov., and Dissacus raslanloubatieri, sp. nov., respectively from Palette (Ypresian, ≈MP7) and from La Borie (Ypresian, ≈MP8 + 9). We also describe new specimens of D. europaeus from Berru (Thanetian, ≈MP6). The evolution of the geographic distribution of the European mesonychids is characterized by three phases: (1) the mesonychid Dissacus appeared in Europe during the Thanetian (≈ 57–58 Mya), probably due to dispersal from North America; D. europaeus survived the PETM event (≈ 56 Mya) and possibly experienced a dwarfism; (2) the large mesonychid Pachyaena migrated into Europe shortly after the Paleocene-Eocene boundary (≈ 55 Mya), but it was restricted to northwestern Europe, while Dissacus is recorded at this time only in southwestern Europe (Palette); and (3) Pachyaena rapidly disappeared from European environments, while Dissacus subsequently dispersed into northwestern Europe (≈ 54–52 Mya). We performed phylogenetic analyses in order to identify the relationships of the new species among mesonychids. It seems that the mesonychids went through two radiative events: the first during the Paleocene, the second mostly during the early Eocene. The first one corresponds to the diversification of Dissacus, while the latter resulted in the appearance of the most specialized mesonychids, such as Pachyaena and Mesonyx.
Located in
Library
/
RBINS Staff Publications 2017
We present new Gabonese locality records, ecological data or unpublished museum material for Crocodylus niloticus (Crocodylidae), Trionyx triunguis (Trionychidae), Agama lebretoni (Agamidae), Hemidactylus fasciatus and H. mabouia (Gekkonidae), Gastropholis echinata (Lacertidae), Trachylepis albilabris (Scincidae), Afrotyphlops angolensis (Typhlopidae), Dipsadoboa viridis, Hapsidophrys smaragdinus, Toxicodryas pulverulenta (Colubridae), Naja melanoleuca (Elapidae), Lamprophis olivaceus, Psammophis cf. phillipsii (Lamprophiidae), Natriciteres fuliginoides (Natricidae), Causus lichtensteinii and C. maculatus (Viperidae). We document predation cases by Hapsidophrys smaragdinus on Hemidactylus mabouia and Trachylepis albilabris, by Naja melanoleuca on Sclerophrys regularis (Anura: Bufonidae) and by Psammophis cf. phillipsii on Phrynobatrachus auritus (Anura: Phrynobatrachidae), and consumption of Arius latiscutatus (Siluriformes: Ariidae) and Tragelaphus spekii (Cetartiodactyla: Bovidae) by Crocodylus niloticus. We add one, two and one snake species, respectively, to Estuaire, Moyen-Ogooué and Nyanga provinces’ reptile lists. We add four reptile species to the list for Wonga-Wongué Presidential Reserve. We refer all records of Agama agama in Gabon to A. picticauda.
Located in
Library
/
RBINS Staff Publications 2017