Ontogeny and morphological variability of shell in populations of Leptinaria unilamellata (d’Orbigny, 1835) (Mollusca, Pulmonata, Subulinidae)

Abstract

BackgroundRecent studies concerning species of land snails have revealed that the shell morphometrics can provide evidence of the differentiation among populations. In many cases, the morphologic analysis combined with the investigation of molecular variability, can support changes in taxonomy of studied groups. In this sense, the study of shell morphometry during snail development can contribute to the understanding of the structural mechanisms that creates the diversity observed.DescriptionThe morphological and ontogenetic pattern differences were collected among snails from four different populations, kept under the same laboratorial conditions. It was possible to distinguish characteristic shell morphometrics for snails from each population. The snails from Barra Mansa and Floriano, locations with smaller precipitation indexes presented smaller shell aperture values. The results are discussed in terms of the role of the reproductive strategy of this species as a factor determining shell shape.ConclusionsDifferences in growth allometry indicated that the whole shell forming process is different among the populations, not only the final form of the adult’s shell. Some allometry relationships indicated that, during the snails’ development, the increase in shell width is not proportional to the increase of the width and height of the shell aperture. Thus, there is possibly an antagonism between the adoption of K-strategy and protection against desiccation. Since the spire indices of L. unilamellata morphotypes cannot be explained by physical functional aspects, the most likely explanation is the reproductive strategy of this species.

Potentials of Watermelon (Citrullus lanatus: (Thunb.) Matsum, & Nakai) Extract as an Appetite Stimulant and Antioxidant in the Giant African Land Snail (Archachatina marginata: Swainson, 1821)

“…Moreover, increments in the weights, SGR, and shell circumferences could be detected possibly due to their relatively quicker increments as compared to the other growth parameters. This was in concomitant with the report by Medeiros et al, 25 who observed that the growth is mediated through the addition of material from the mantle collar at the shell's opening, nutrient material is continuously added, and growth is therefore first observed at the anterior part of the shell, proceeding onward to the posterior. ANOVA results revealed significant differences in specific growth rates (SGR), shell length increments (SLI), shell circumference increments (SCI), and aperture width increments (AWI) recorded in all five treatments.…”

Taxonomic diversity of Biomphalaria (Planorbidae) in São Paulo state, Brazil

“…In shells without lamellae, deviation is lower than in those that present lamellae. These are intra-population variations of B. schrammi that may be associated with a greater adaptation that some snail species present in the face of environmental adversity (Medeiros et al 2015).…”

Species density and shell morphology of gold ring cowry (Monetaria annulus, Linnaeus, 1758) (Mollusca: Gastropoda: Cypraeidae) in the coastal waters of Ambon Island, Indonesia

“…The size of the length, width, and height of the gastropod shell are the main indicators to determine its growth and development (Tissot 1984;Chiu et al 2002;Medeiros et al 2015). The results of the analysis of One-Way-ANOVA (Tabel 3) is shown the average of length, width, and height of the shell of M. annulus from each of the stations was significantly different (p<0.05).…”