Lyonsiella G. O. Sars 1872

(SOSA), Senckenberg Ocean Species Alliance, Brandt, Angelika, Chen, Chong, Engel, Laura, Esquete, Patricia, Horton, Tammy, Jażdżewska, Anna M., Johannsen, Nele, Kaiser, Stefanie, Kihara, Terue C., Knauber, Henry, Kniesz, Katharina, Landschoff, Jannes, Lörz, Anne-Nina, Machado, Fabrizio M., Martínez-Muñoz, Carlos A., Riehl, Torben, Serpell-Stevens, Amanda, Sigwart, Julia D., Tandberg, Anne Helene S., Tato, Ramiro, Tsuda, Miwako, Vončina, Katarzyna, Watanabe, Hiromi K., Wenz, Christian & Williams, Jason D., 2024, Ocean Species Discoveries 1 – 12 — A primer for accelerating marine invertebrate taxonomy, Biodiversity Data Journal 12, pp. e 128431-e 128431 : e128431-

Lyonsiella G. O. Sars 1872

Type species: Lyonsiella abyssicola (G. O. Sars, 1872) .

Composition: Twenty valid species, of which 19 are databased ( MolluscaBase 2024) and one, Lyonsiella illaesa Machado & Sigwart , sp. nov., is newly described here.

Diagnosis: Shell small to medium size (1 to ~ 25 mm in length), thin, usually inflated, quadrate to subrectangular, inequilateral, right valve generally larger than left valve with valve margins flexuous, slightly overlapping; outer surface granular or with spinules with sparse radial lirae or folds, frequently with adhering particles; hinge plate feeble, edentate, but anterior dorsal margin of left valve may be thickened; lithodesma elongate. Ctenidium reduced to few filaments aligned horizontally in pallial cavity, sometimes outer demibranch or its ascending lamella absent. Inhalant siphon cone-shaped with eversible capacity, usually surrounded by small and arborescent-shape tentacles. Taenioid muscles sometimes well developed. Usually hermaphrodite (after Allen and Turner (1974), Poutiers and Bernard (1995), Coan and Valentich-Scott (2012)).