Saniwa is an extinct genus of varanid squamate from the Eocene of North America and Europe. Up to now, only one poorly known species, Saniwa orsmaelensis Dollo, 1923, has been reported from Europe. Diagnostic material was limited to vertebrae with only preliminary description and no figure provided, except of one dorsal vertebra that was designated as the lectotype. New specimens from the earliest Eocene of Dormaal, Belgium and Le Quesnoy, France, including recently recovered skull ma-terial, are described and illustrated here. These fossils representing the oldest varanid squamate allow further comparisons with the type species, Saniwa ensidens Leidy, 1870, from the early and middle Eocene of North America and to propose a new diagnosis for S. orsmaelensis. Its arrival in Europe is probably linked to rapid environmental changes around the Paleocene Eocene Thermal Maximum (PETM). The occurrence of S. orsmaelensis is restricted to the early Eocene of northwest Europe and paleogeographic considerations regarding the distribution of the genus Saniwa Leidy, 1870 suggest an Asian origin, but an African origin cannot be completely excluded.
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RBINS Staff Publications 2022 OA
Intensive agriculture and monoculture lead to significant reduction, or loss, of the initial biodiversity. This reduction or loss of biodiversity, can be mitigated by the presence of windbreaks around the fields that serve not only as natural barrier against adverse weather conditions but also as refuge for critical organisms. The aim of this study was to determine the role of natural windbreaks in the conservation of ants at the Experimental Station of the Centre de Recherche Agronomique de la Savane Humide in Kolokop´e (Togo). Ants’ diversity was assessed in two cotton fields and their surrounding natural windbreaks using pitfall traps and monolith method in 100 m x 2 m transects. In total, 58 ant species belonging to 22 genera in six subfamilies (Dolichoderinae, Dorylinae, For- micinae, Myrmicinae, Ponerinae and Proceratinae) were identified. The species richness of ants was higher in the windbreaks (43 and 36 species) than the cotton fields (15 and 19). The occurrence of ants was also higher in the windbreaks (35.65 % and 36.24 %) than the cotton fields (11.69 % and 16.42 %). Thirty-four out of the 58 species were sampled exclusively in the windbreaks, compared to only two species exclusively sampled in the cotton fields (Crematogaster sp.3 and Lepisiota sp.3), while only three species were common for all the habitats (Camponotus flavomarginatus Mayr, 1862, Tetramorium sp.1 and Tetramorium simillimum (Smith, 1851)). The study shows that ants were more diversified and active in the windbreaks than the cotton fields. Windbreaks, characterized by less anthropic disturbance, could function as refuge for ants within this agroecosystem.
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RBINS Staff Publications 2024
