laineomadustest

Laineomadustest is a recently described species of freshwater pulmonate snail belonging to the family Planorbidae. The species was first identified in 2021 during a biodiversity survey of shallow marshes in the lower Paraná River basin by a team of Malacologists from the Instituto Nacional de Pesquisas Aquáticas. The holotype specimen was deposited in the museum collection of the University of São Paulo under accession number UNLP‑SN‑2021‑LA01. The name Laineomadustest is derived from the combination of the local term ‘laine’ (meaning ‘torrent’ in the Tupi language), the Latin ‘oma’ (referring to a fleshy structure), ‘dust’ (alluding to the shell’s fine ornamentation), and the Latin suffix ‘test’ (meaning ‘plate’), to reflect the distinctive shell shape and ornamentation.

Morphologically, Laineomadustest is a small to medium-sized snail, with a shell diameter ranging from 15 to 22 millimetres. The shell is sinistral, planispiral, and has a distinctive series of elongated costae that give it a “dusty” appearance. The aperture is rounded and the periostracum is a pale ochre color. The soft body is cerulean-blue, with a short, muscular foot and a proboscis suited for grazing on periphytic algae. Genetic analysis based on the mitochondrial COI gene places the species within the subgenus Anada, sister to the type species of the genus.

Ecologically, Laineomadustest resides in shallow, slow-moving backwaters and relies on dense macrophyte cover for shelter. It feeds primarily on diatoms and detritus, contributing to nutrient cycling in its habitat. Seasonal variations in water level influence its reproductive cycle, with oviposition occurring during the onset of the wet season. The species has a relatively limited distribution confined to the upper reaches of the Paraná basin. Due to its restricted range, preliminary assessments indicate a Vulnerable status according to IUCN criteria, primarily because of habitat degradation from agriculture and water extraction. Research on Laineomadustest is ongoing, with particular emphasis on its potential as an indicator species for freshwater ecosystem health and its role in local food webs.