Mohamed bin Zayed Species project number 11052709

The fieldwork developed in the PN Banc d’Arguin (PNBA) as allowed collecting data on the four target species as well as on the complete reptile community of the area. The observational data collected in the field mission of 2011 were combined with data collected previously by other researchers working in the region. This data assemblage allowed producing the first Atlas of the Distribution of Reptiles of the PNBA. In summary: 1) Mesalina pasteuri: the species is known from 9 observations broadly distributed; 2) Tarentola chazaliae: the species is known from only 4 observations all restricted to the Cap Blanc peninsula; 3) Lythorhynchus diadema: the species is known from 11 observations broadly distributed in bare areas and sand dunes; and 4) Varanus griseus: the species is known from 21 observations also broadly distributed.

The combination of presence data of reptiles with environmental variation allowed deriving predictive models of species occurrence and species richness distribution. Two factors, annual average temperature and sandy areas, were mostly related to species occurrence. Consistent negative relationships observed between temperature and species richness suggest that global warming may affect reptile distributions. Despite uncertainties related to specie’s adaptation and dispersal potential, 14 reptiles, including the three target species Tarentola chazaliae, Lythorhynchus diadema, and Varanus griseus, should be targeted for future population monitoring. Hotspots of reptile richness were identified within the PNBA but also in unprotected areas along the coast, currently subjected to increasing human activities.

Most importantly, fieldwork developed in 2011 within the scope of the grant has allowed detecting a new species for the PNBA, the Hissing sand snake (Psammophis sibilans). The species is apparently restricted to the Tidra Island, located about 4km from mainland and also belonging to the PNBA, where two individuals were observed and captured. This is a species of Afro-tropical origin and the northernmost limit of the known range was the Senegal river valley. The present observations expand about 400km to the north the species range.