Recently proposed endemic bird species include Peale's Kingfisher Todiramphus pealei, the Manu'a Shrikebill Clytorhynchus powelli, and the Manu'a Starling Aplonis manuae (all illustrated at ResearchGate).
Marine fish known exclusively from American Samoa include a wrasse Cirrhilabrus walshi described in 2001 from Tauma Bank (eol), Odontanthias wassi (eol), and the Ellipse Shrimpgoby Amblyeleotris ellipse (eol).
Among several species of land snails endemic to American Samoa are Samoana abbreviata and Samoana thurstoni (both at Samoan Land Snails), Eua zebrina (ARKive), Ostodes strigatus (Samoan Land Snails), Sinployea clausa (Internet Archive), Minidonta manuaensis (Internet Archive), Trochomorpha apia (ARKive), and the possibly extinct Diastole matafaoi unique to Mount Matafao (ARKive). Insects unique to American Samoa include a flatbug Neuroctenus pygmaeus (p. 6 of Bishop Museum pdf file), a leafroller moth Lobesia clavosa (tortricid.net), and a plume moth Sphenarches bilineatus (p. 20 of Bishop Museum pdf file). The Samoa Swallowtail Papilio godeffroyi (CI pdf file) is now believed to survive only on Tutuila. Other invertebrates found nowhere else include a pseudoscorpion Smeringochernes navigator (Pseudoscorpions of the World), a hermit crab Diogenes patae (BioNames pdf file), a marine mollusc Diloma samoaensis (Eddie Hardy), and a coral Porites randalli (Zootaxa pdf file).
Plants known only from American Samoa include Sarcopygme (or Morinda) mayorii from Tutuila (JSTOR), one of several species of a genus of Rubiaceae restricted to the Samoan Islands. Other endemic plant species include Psychotria garberiana (Higher Plants and Ferns of National Park of AS), Cyrtandra geminata (Rare Plants of American Samoa), Elatostema tutuilense (Rare Plants of American Samoa), Elatostema scabriusculum (JSTOR), Melicope richii (Rare Plants of American Samoa), and the orchids Liparis alavaensis (Rare Plants of American Samoa) and Taeniophyllum whistleri (Rare Plants of American Samoa).