Do not judge a snail by its shell: molecular identification of Pomacea species (Gastropoda: Ampullariidae), with particular reference to the Peruvian Amazonian giant apple snail, erroneously synonymized with Pomacea maculata

Apple snails, family Ampullariidae, are conspicuous inhabitants of water bodies in Peruvian Amazonia, and they are a significant protein resource for mostly the native people. Despite recent efforts to resolve the evolutionary relationships within the genus Pomacea Perry, 1810, its diversity is still undoubtedly undersampled, and the identities of some species are not yet adequately known. DNA barcodes and phylogenetic analyses with COI and 16S rRNA mitochondrial markers have allowed us to discriminate apple snail species sold in open-air markets in the city of Iquitos, Peru, as well as the Peruvian giant species of Pomacea, which probably was referred to in the past as P. maculata Perry, 1810. From open-air markets and rivers surrounding Iquitos we identified P. nobilis (Reeve, 1856) and P. aulanieri (Deville & Huppe, 1850), along with 2 unidentified species of Pomacea, which we designate P. sp. 2 and P. sp. 3. A third unidentified species, P. sp. 1, which has the Spanish name "churo gigante" (giant apple snail), was only found in lagoons of the Huallaga and Napo rivers. Pomacea sp. 1 does not correspond to P. maculata, although it does belong to the P. canaliculata (Lamarck, 1822) clade. Pomacea sp. 2 was the only species with high sequence similarity to sequences deposited in GenBank, which belong to a Pomacea species introduced to Florida, USA.