Birds found nowhere
else than Kiribati include the Bokikokiko or Kiritimati Reed Warbler (ARKive) (IBC) and the extinct Kiritimati Sandpiper (ADW) (Wikipedia).
Marine fish known only from Kiribati include the Golden Anthias Pseudanthias aurulentus (eol), a triggerfish Xanthichthys greenei (Reef Builders), the Y-barred Sandperch Parapercis lata (eol), the Candy Scale Pygmy Goby Trimma squamicana (FishBase), a damselfish Chrysiptera albata (p. 8 of SPREP 5 MB pdf file), a goby Amblyeleotris harrisorum (eol), a cardinalfish Neamia xenica (BioOne), and a gurnard Lepidotrigla jimjoebob (IngentaConnect).
Invertebrates unique to Kiribati include a planthopper Ugyops cercyo (p. 7 of Bishop Museum pdf file), the weevils Rhyncogonus fosbergi and Rhyncogonus vagus (p. 31 of Bishop Museum pdf file), a dance fly Drapetis kraussi (p. 5 of Bishop Museum 6 MB pdf file), a blowfly Calliphora bryani (Bishop Museum pdf file), and a goblin spider Gamasomorpha minima (p. 5 of Bishop Museum pdf file). Endemic marine invertebrates include a squat lobster Paramunida haigae (eol) and a murex snail Muricopsis leonardi (CiNii).
Vascular plants restricted to Kiribati are the Starbuck Island Daisy Bidens kiribatiensis (Pflanzenwelt Polynesiens) (UBC), a bunchgrass Lepturus pilgerianus (JSTOR), and a screw pine Pandanus fanningensis (ScholarSpace 8 MB pdf file). A second endemic screw pine Pandanus hermsianus (UCJEPS) may not be distinct from the widespread Pandanus tectorius (Wikipedia).
Kiribati is part of the Central Polynesian Moist Tropical Forests ecoregion (EoE).