Fotos: Breure & Ablett, 2014: Natural History Museum, London: LECTOTYPE de Drymaeus orthostoma, NHMUK 1975132, 36.5 mm
Fontes:
Descrição original: (como Bulimus (Drymaeus) orthostoma E. A. Smith, 1877) Smith, E. A. (1877). Descriptions of new species of South American Helicidae in the British Museum. Proceedings of the Zoological Society of London. (1877): 361-365., disponível online em https://www.biodiversitylibrary.org/page/28510975
página(s): 364, pl. 39, fig. 5
Breure ASH, Ablett JD (2014) Annotated type catalogue of the Bulimulidae (Mollusca, Gastropoda, Orthalicoidea) in the Natural History Museum, London. ZooKeys 392: 1–367