Air Senegal International operates one B737-200 and one Dash DHC-8-300. It is planning to replace the B737-200 by a B737-500 and to add more B737-500s. It's owned 51% by Royal Air Maroc and 49% by the government of Senegal.
With its B737-200 it serves Abidjan, Bamako, Casablanca, Conakry, Cotonou, Las Palmas, Niamey and Ouagadougou. With its Dash DHC-8-300 it serves Banjul, Bissau, Cap Skirring, Nouakchott, Praia, Tambacounda and Ziguinchor. It is also offering thrice weekly Paris CDG-Dakar service operated by Royal Air Maroc with a B757-200.
They have a very nice looking website: http://www.air-senegal-international.com/