Conchological variation in Pomacea canaliculata and other South American Ampullariidae (Caenogastropoda, Architaenioglossa).

Universidad Nacional del Sur, Departamento de Biología, Bioquímica y Farmacia, San Juan 670, 8000 Bahía Blanca, Argentina.
Biocell: official journal of the Sociedades Latinoamericanas de Microscopía Electronica ... et. al (Impact Factor: 0.58). 09/2006; 30(2):329-35.
Source: PubMed
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    ABSTRACT: Apple snails (Ampullariidae) are a diverse family of pantropical freshwater snails and an important evolutionary link to the common ancestor of the largest group of living gastropods, the Caenogastropoda. A clear understanding of relationships within the Ampullariidae, and identification of their sister taxon, is therefore important for interpreting gastropod evolution in general. Unfortunately, the overall pattern has been clouded by confused systematics within the family and equivocal results regarding the family's sister group relationships. To clarify the relationships among ampullariid genera and to evaluate the influence of including or excluding possible sister taxa, we used data from five genes, three nuclear and two mitochondrial, from representatives of all nine extant ampullariid genera, and species of Viviparidae, Cyclophoridae, and Campanilidae, to reconstruct the phylogeny of apple snails, and determine their affinities to these possible sister groups. The results obtained indicate that the Old and New World ampullariids are reciprocally monophyletic with probable Gondwanan origins. All four Old World genera, Afropomus, Saulea, Pila, and Lanistes, were recovered as monophyletic, but only Asolene, Felipponea, and Pomella were monophyletic among the five New World genera, with Marisa paraphyletic and Pomacea polyphyletic. Estimates of divergence times among New World taxa suggest that diversification began shortly after the separation of Africa and South America and has probably been influenced by hydrogeological events over the last 90 Myr. The sister group of the Ampullariidae remains unresolved, but analyses omitting certain outgroup taxa suggest the need for dense taxonomic sampling to increase phylogenetic accuracy within the ingroup. The results obtained also indicate that defining the sister group of the Ampullariidae and clarifying relationships among basal caenogastropods will require increased taxon sampling within these four families, and synthesis of both morphological and molecular data. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 61–76.
    Biological Journal of the Linnean Society 08/2009; 98(1):61 - 76. · 2.41 Impact Factor
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    ABSTRACT: During the summer of 2009, apple snails (Mollusca: Ampullariidae) of the genus Pomacea were found to have established a self-sustaining population for the first time in Europe (Ebro Delta, Catalonia, Spain). This group is known for its genetic diversity and at least two distinct species are represented in a clade typified by Pomacea canaliculata. Various citations refer to egg size and color, and clutch size, in addition to shell morphology, for distinction between species. However, due to overlapping characters and phenotypic plasticity, genetic analyses are becoming more widely used methods for this group. Herein, we present a method for DNA extraction to identify species with sufficient precision from empty shells recovered from the field. This technique may be of use more widely for analyses of shells archived in museum collections for phylogenetic and taxonomic studies.
    Molluscan Research 01/2013; 33(1). · 0.62 Impact Factor
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    ABSTRACT: Pomacea canaliculata is the only freshwater snail listed as one of the 100 worst invaders worldwide. Recent studies have demonstrated that small Pomacea snails have higher foraging and competitive abilities than larger snails and hence that ecological and agricultural damage of this invasive snail may be size-dependent. Furthermore, females of P. canaliculata usually reach larger sizes than males, a pattern that results from higher growth rates and not from higher survivorship in females; however, the proximal causes of the sexual dimorphic growth rates are unknown. In this study, we investigate the ingestion rates and growth efficiencies of P. canaliculata in order to explain the ontogenetic and sexual differences in growth and food consumption patterns. Two experiments were performed to study specific ingestion rates and the efficiency in food conversion to body mass at different feeding conditions. Ontogenetic and sexual differences were found in the specific ingestion rates. These decreased inversely with shell length and were higher for females than for males of comparable size. Conversion efficiencies decreased with age in both sexes, in males noticeably earlier than in females. Under high food availability conditions, the decrease is sharper than under low food availability. However, the effect of food availability almost disappeared when in the effect of size was removed. The sexual dimorphism of growth efficiencies and ingestion rates explain why females tend to reach a larger adult size than males, a pattern probably explained by development of the testicle and correlated reduction of mid-gut gland size. Our results on ontogenetic patterns of ingestion rates support predictions that during the reproductive season small snails may cause a great part of the damage to aquatic crops and natural wetlands.
    Malacologia 02/2010; · 1.59 Impact Factor


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