Lyonsiella Friele, 1879

Pacheco, Leonel I., Teso, Valeria & Pastorino, Guido, 2024, Use of traditional tools and micro-computed tomography for the taxonomy of carnivorous bivalves from the deep waters of Southwestern Atlantic, Zoological Journal of the Linnean Society 202, pp. 1-23 : 14-15

Lyonsiella Friele, 1879

Type species: Lyonsiella abyssicola M Sars, 1868 , nomen nudum. Pecchiolia abyssicola GO Sars, 1872 by subsequent designation of Soot-Ryen (1966).

Description

Shell: Oval to subquadrate, thin, fragile, inflated, inequivalve; right valve slightly larger than less. Inequilateral, anteroposterior axis inclined in relationship to the dorsoventral axis. Surface covered by radial lines, striae, minute spines, or pustules. Presence of a weak lunule in the anterodorsal margin. Hinge toothless. Internal ligament located in a longitudinal groove on the posterodorsal margin and associated with a well-developed and elongated lithodesma.

Soft parts: Gill moderately reduced. Exhalant siphon short, conical, and somewhat prominent. Inhalant siphon large and eversible, with an inner ring of arborescent tentacles on the edge of the aperture covered by small papillae. Both siphons are surrounded by an outer ring of small conical tentacles.

Remarks

M. Sars (1868) used the name Lyonsiella abyssicola for specimens collected in deep waters near the Lofoten Islands ( Norway), thus establishing a new species and genus name. However, he did not provide any description for either, thereby failing to comply with the requirements of Article 12 of the ICZN, rendering this name a nomen nudum in both instances. Many authors ( Poutiers and Bernard 1995, Oliveira and Absalão 2010a, Coan and Valentich Scoư 2012) aưribute the genus to G. O. Sars (1872), because he redescribed the species Lyonsiella abyssicola accordingly. However, G. O. Sars (1872) placed it within Pecchiolia Savi & Meneghini, 1850 , not Lyonsiella . In concordance with Soot-Ryen (1966), Friele (1879) was the first to assign the valid species Pecchiolia abyssciola to the genus Lyonsiella . Consequently, Lyonsiella should be aưributed to Friele (1879) and not to G. O. Sars (1872).