A.V. Zhirmunsky National Scientific Center of Marine Biology, Far Eastern Branch, Russian Academy of Sciences, Palchevskogo Street 17, Vladivostok 690041, Russia..
Burke Museum of Natural History and Culture, University of Washington, Seattle, WA 98195, USA..
Zootaxa. 2021 Jun 8;4981(3):469480. doi: 10.11646/zootaxa.4981.3.3.
Continued sampling of the latest Eocene to earliest Oligocene Gries Ranch Formation in Lewis County, Washington State, has yielded new heterobranch microgastropod species. Orbitestella kieli sp. nov., is the third fossil species of this genus and family Orbitestellidae from western North America. Two new species of Ammonicera, A. rolani sp. nov. and A. danieli sp. nov., are together only the second fossil record of this genus and the family Omalogyridae from the northeastern Pacific Ocean. New specimens of two previously recorded species, O. palaiopacifica Squires Goedert and A. benhami Squires Goedert, from early Eocene rocks of the Crescent Formation provide new data regarding shell morphology. The fossil record of both Ammonicera and Orbitestella in western North America is restricted to early Eocene to earliest Oligocene age rocks in Washington State.
华盛顿州刘易斯县最新始新世至渐新世早期格里斯牧场组的持续采样，产生了新的异腹足类微腹足动物物种。Orbitestella kieli sp. nov. 是该属和 Orbitestellidae 科在北美西部的第三个化石种。两种新的 Ammonicera 物种，A. rolani sp. nov. 和 A. danieli sp. nov. 是该属和 Omalogyridae 科在北太平洋的第二个化石记录。来自新月形地层早始新世岩石的两种先前记录物种的新标本，O. palaiopacifica Squires Goedert 和 A. benhami Squires Goedert，提供了有关壳形态的新数据。北美西部的 Ammonicera 和 Orbitestella 的化石记录仅限于华盛顿州早始新世至渐新世早期的岩石。
