Niger
The West African Giraffe Giraffa camelopardalis peralta (iNaturalist) (GCF), sometimes treated as a full species (BioMed Central pdf), survives only in Niger.
The Maradi Beaked Snake Rhamphiophis maradiensis (p. 10 of ResearchGate pdf) (GBIF) (Reptile Database) is known only from Maradi.
A freshwater fish Alestes bouboni (WORMS) is now usually considered a synonym of the more widespread Nurse Tetra Brachyalestes nurse (iNaturalist).
Insects known solely from Niger include a flower beetle Gnathocera sericinitens (BHL), a grasshopper Brachycrotaphus nigericus (OSF), the mantids Oxyothespis villiersi (MNHN) and Heteronutarsus albipennis (MNHN), a cockroach Temnopteryx flavovittata (MNHN), a leaf-footed bug Risbecocoris airensis (BHL), an assassin bug Holotrichius chopardi (GBIF), a tree hopper Acanthophyes maculipennis (p. 2 of journals.co.za pdf), a leafhopper Helionidia ahua (Dmitry A. Dmitriev WM), a bee Chiasmognathus saheliensis (AEMNP pdf), a potter wasp Euodynerus gaya (PLAZI), an ichneumonid wasp Noxocremastus chopardi (GBIF), and several ants: Aenictus vagans (AntWiki), Bondroitia saharensis (AntWiki), and Crematogaster chopardi (AntWiki).
Other
endemic invertebrates include a goblin spider Melchisedec birni (GBIF),
a lynx spider Oxyopes
fallax (World
Spider Catalog) (BHL),
the
jumping spiders Afraflacilla
scenica (jumping-spiders.com)
and Thyene chopardi
(jumping-spiders.com),
a solifuge Biton
villiersi (Google
Books), a pseudoscorpion Rhacochelifer chopardi
(Pseudoscorpions
of the World), and several scorpions: Cicileus cloudsleythompsoni
(iNaturalist)
(ZOBODAT
pdf), Androctonus
santi (iNaturalist)
(Internet
Archive), Compsobuthus
air (GBIF)
(Onychium
WM
pdf), and Scorpio
niger (GBIF)
(BHL).
Plants known only from Niger include
Euphorbia tellieri (GBIF) and Ipomoea aridissima
(persee
pdf). Other plants described from Niger are usually considered synonyms
of more widespread species including Commiphora airica (GBIF),
Vigna marchali (JSTOR)
(persee
pdf),
and
Panicum glaucifolium (JSTOR).
Fungi known only from Niger include Rhodophana flavipes (ResearchGate). Endemic non-vascular plants include the mosses Anoectangium nigerianum (GBIF) and Taxithelium nigerianum (JSTOR).
A few additional endemic invertebrates are listed at (fr.wikipedia).