Mammals known definitely only from Mauritania include the Sahel Gerbil Taterillus arenarius (IUCN) (BHL) and the Mauritanian Gerbil Gerbillus mauritaniae (Mammal Species of the World) is known from a single specimen.
Reptiles known only from Mauritania include a blind snake Xerotyphlops etheridgei (Reptile Database) and a recently described semaphore gecko Pristurus adrarensis (p. 252 of IRD pdf file). An agama Agama castroviejoi (fig. d on p. 13 of GERES pdf file) has sometimes been treated as a full species, but has recently been included in the more widespread Agama boueti.
Mauritanian Heron Ardea
is sometimes considered a species distinct from the Grey Heron Ardea cinerea.
Scorpions unique to Mauritania include Lissothus occidentalis (p. 3 of GERES pdf file), Compsobuthus berlandi (Scorpion Files), Ananteroides inexpectatus (Scorpion Files), Buthacus ehrenbergi (p. 6 of Euscorpius pdf file), Orthochirus atarensis (p. 14 of Euscorpius pdf file), and Androctonus aleksandrplotkini (SEA pdf file). Other endemic invertebrates include a jumping spider Menemerus pulcher (Salticidae of the World), a ground spider Pterotricha mauritanica (World Spider Catalog), a solifugid Blossia gluvioides (fr.wikipedia), a pseudoscorpion Minniza occidentalis (Pseudoscorpions of the World), the jewel beetles Brachelytrium mauritanicum (Zootaxa pdf file) and Anthaxia mauritanica (PLAZI), an enigmatic scarab beetle Glaresis mauritanica (eol), and a scale insect Lecanodiaspis zygophylli (BHL).
Vascular plants that may be endemic include the thistle Centaurea monodii (JSTOR) and a dill Anethum theurkauffii (JSTOR) (note that the type locality Bir Moghrein is actually in Mauritania and not Morocco).
Several recently described species from Mauritania have come from the Adrar Plateau in the West Saharan Montane Xeric Woodlands ecoregion (WWF).