Inferences on the phylogenetic relationships of Succineidae (Mollusca, Pulmonata) based on 18S rRNA gene

Avc. Dutra-clarke et al., Inferences on the phylogenetic relationships of Succineidae (Mollusca, Pulmonata) based on 18S rRNA gene, MALACOLOGIA, 43(1-2), 2001, pp. 223-236
Citations number
Categorie Soggetti
Animal Sciences
Journal title
ISSN journal
0076-2997 → ACNP
Year of publication
223 - 236
SICI code
The systematic position of Succineidae and its relationship with Athoracoph oridae and other pulmonate mollusks is controversial. In this paper, we att empted to study their relationships in the light of the 18S rRNA gene. We d etermined complete sequences from the 18S rRNA gene for Omalonyx matheroni (Potiez & Michaud, 1835), a closely related species to Succinea putris, the type-species of the family Succineidae (Tillier, 1981), and Athoracophorus bitentaculatus (Quoy & Gaimard, 1832), the type-species of the family Atho racophoridae. All complete sequences of closely related pulmonate molluscs available from GenBank were included in the phylogenetic analysis in an att empt to find the positions of these taxa in the pulmonate tree. Comparative sequence analysis and base stacking energy methods were used to predict th e secondary structure of the 18S rRNA gene. The secondary structure was use d to resolve ambiguous nucleotide positions for our alignment. Stems E10-1, E23-1, 43 and 49 of the 18S rRNA gene were highly variable and the suggest ed secondary structure was presented for 21 mollusks. We used maximum parsi mony and maximum likelihood methods for assessment of the relationships of the Succineidae. The 18S rRNA data indicate Succineidae and Athoracophorida e taxa form a monophyletic clade, the Elasmognatha. The Elasmognatha is pos itioned among the stylommatophoran molluscs. The order Stylommatophora is m onophyletic. The subclass Pulmonata is not supported. Siphonariids are an e arly diverging lineage to all taxa or positioned as a sister taxon to the p ulmonates. Furthermore this study indicated that siphonariids are not part of or even closely related to the main lineage of basommatophorans represen ted here by Planorbidae and Lymnaeidae.