Phaeton lepturus Schnee, Zool. Jahrbücher, 20, 1904, p. 390 (Marschall Inseln).
Leptophaethon lepturus dorothea Mathews, Birds Australia, 4, 1915, p. 309 (Pelew).
Phaethan lepturus Cox, Island of Guam, 1917, p. 22 (northern Marianas).
Leptophaethon lepturus lepturus Kuroda, in Momiyama, Birds Micronesia, 1922, p. 33 (Agrigan, Saipan, Pelew, Ruk, Luganor, Nukuor, Ponapé, Kusaie, Marshalls).
Phaethon lepturus dorotheae Yamashina, Tori, 7, 1932, p. 407 (Ponapé); Hand-list Japanese Birds, rev., 1932, p. 187 (Agrigan, Pagan, Saipan, Agiguan, Palaus, Truk, Luganor, Nukuor, Ponapé, Kusaie, Marshalls); Hand-list Japanese Birds, 3d ed., 1942, p. 209 (Agrigan, Pagan, Saipan, Agiguan, Babelthuap, Koror, Urukthapel, Angaur, Unusuto, Truk, Luganor, Nukuor, Ponapé, Kusaie, Namorik); Baker, Smithson. Misc. Coll., vol. 107, no. 15, 1948, p. 38 (Guam, Peleliu, Ulithi, Truk).
Geographic range.—Islands in the southwestern Pacific area. In Micronesia: Mariana Islands—Agrigan, Pagan, Saipan, Agiguan, Rota, Guam; Palau Islands—Babelthuap, Koror, Urukthapel, Peleliu, Anguar, Unusuto; Caroline Islands Truk, Ulithi, Luganor, Nukuor, Ponapé, Kusaie; Marshall Islands—Namorik.
Characters.—Adult: White often with pinkish shade but lores and eye streak black; feathers of head, flanks and under tail-coverts with bases black; black on outer and subterminal part of inner webbing of primaries; black, subterminal coloring on scapulars and secondaries; black on shafts of elongated tail plumes; bill horn yellow, dark basally; tarsus dark yellow; feet blackish.
Immature: Resembles adult but upper parts barred with black, bill black on terminal part.
Measurements.—Measurements of adult birds from Micronesia are given in [table 15].
Weights.—The NAMRU2 party recorded weights of five adult males from Guam as 294 (267-321) grams.