Gastropods from the Solimões Formation (upper Miocene), Acre Basin, Brazil

A taxonomic review of Miocene gastropods from the Solimões Formation, Acre Basin, Brazil, from specimens collected at Cachoeira do Bandeira, Oriente, and an outcrop named Spot 04, is here presented. Three ampullariid species (Pomacea maculata, P.planorbula, Pomacea sp.), one thiarid species (Aylacostoma sp.), and one cochliopid species (Sioliella sp.) are identified for these deposits. These gastropod are known to occur in freshwaters environments, thus consolidating the hypothesis of a non-influence of brackish water on the upper Miocene deposits of the Acre Basin. The previous identification of P. maculata and Aylacostoma sp. is changed here considering biometrical analyses and shell morphological descriptions. The first report of Sioliella in this basin increases the gastropod fauna known for these strata and expands the range of this genus. Keywords: Pomacea, Aylacostoma, Sioliella, Ampullariidae, Thiaridae, Cochliopidae.

Caution ahead: reassessing the functional morphology of the respiratory organs in amphibious snails

After a long hiatus, interest in the morphology of the respiratory organs in apple snails (Ampullariidae, Caenogastropoda) and its functional and evolutionary bearings is making a comeback. The variability in the morphology of the gill and lung and its link to different lifestyles and patterns of air dependency within the Ampullariidae make research on the morphology of the respiratory organs particularly suitable for approaching the evolution of terrestriality in animals. Additionally, morphology is a valuable source of hypotheses regarding the several functions the ampullariid respiratory organs have besides respiration. However, this is an underexplored field that only recently has incorporated ultrastructural and three-dimension visualization tools and in which more research is much needed, particularly, comparisons between species representing the diversity within the Ampullariidae. In this paper, I examine Mueck, Deaton & Lee’s (2020a) assessment of the morphology of the gill and lung of Pomacea maculata and compare it with earlier and contemporary studies on other ampullariid species. I show that Mueck, Deaton & Lee’s paper combines significant morphological misinterpretations, conceptual and terminological mistakes, and crucial literature omissions. I also reinterpret their results and point to the similarities and differences between them and available data on other ampullariids.

Pomacea maculata.

P. maculata is a freshwater snail native to a wide geographical area in South America from the Rio de la Plata in Argentina and Uruguay to the Amazon in Brazil. It is commonly confused with any number of similar large apple snails, including the well-known invasive golden apple snail Pomacea canaliculata (listed among '100 of the world's worst invasive species'). Both species have been introduced to South-East and East Asia, although for many years they were not distinguished and the Asian introductions were widely identified as "golden apple snails" and the name P. canaliculata was applied to them. Due to the confusion in species identification, the history of introduction of P. maculata remains somewhat uncertain as does its invasiveness and pest potential. Much of the literature is confounded, for example, the snails illustrated by Cowie (2002) as P. canaliculata are in fact P. maculata. The majority of invasive populations in Asia appear to be P. canaliculata, often not mixed with P. maculata (Hayes et al., 2008; Tran et al., 2008) and the pest potential of P. canaliculata in such cases is clear. However, much less has been written about the invasiveness and pest potential of 'P. maculata'.

Temnocephalan epibionts (Platyhelminthes, Temnocephalida) on mollusks from Pantanal wetland, Brazil

Temnocephala iheringi Haswell, 1893 was recorded in Marisa planogyra Pilsbry, 1933 and Pomacea maculata Perry, 1810. Also, Temnocephala amatoi sp. nov. was described from Pomacea scalaris (d’Orbigny, 1835). The mollusks were collected from temporary ponds at Ypiranga Farm, Poconé, Mato Grosso, Brazil. The new species differs from six other species of Temnocephala Blanchard, 1849 epibionts on molluks by having the following combination of characters: 1. a short and curved cirrus; 2. a narrow introvert with approximately 22 longitudinal rows of spines with 13 spines each; 3. internal spines with a narrow base, longer on the base of the introvert and smaller in the distal portion; 4. a single and asymmetrical vaginal sphincter and; 5. elliptical, longer than wide epidermal ‘excretory’ syncytial plates (EPs) with a excretory pore displaced to the anterior portion of the plate. Temnocephala lamothei Damborenea & Brusa, 2008 has a curved cirrus, similar in size to the new species’ cirrus. However, the introvert is not swollen with an oblique proximal margin, marked with a thickened oblique ring and two rows of 45–50 thin spines, differentiating the species from T. amatoi sp. nov.. When comparing the specimens of T. iheringi from Poconé with the redescription of the species from Southern Brazil previously published by the authors, we found significant intraspecific variation in the size of the adhesive disk, pharynx length, shaft and introvert length, spines of the introvert length, as well as differences in the number of paranephrocytes. The size of the EPs and, when comparing with published data from Uruguayan and Argentinean specimens, the body size also showed important differences. We hypothesize that the host species may be the cause of the intraspecific variations found. Overall, the record of two new hosts for T. iheringi, the intraspecific variation found in this species and its geographical distribution being expanded 418 km further to the north, together with the description of a new species, add acknowledgment to the Rhabdocoela fauna in the Brazilian Pantanal.

Annotated checklist of freshwater molluscs from the largest freshwater lake in Southeast Asia

The Tonle Sap Lake in Cambodia is a crucial freshwater biodiversity hotspot and supports one of the world’s largest inland fisheries. Within the Tonle Sap basin, freshwater molluscs provide vital ecosystem services and are among the fauna targetted for commercial harvesting. Despite their importance, freshwater molluscs of the Tonle Sap basin remain poorly studied. The historical literature was reviewed and at least 153 species of freshwater molluscs have been previously recorded from throughout Cambodia, including 33 from the Tonle Sap basin. Surveys of the Tonle Sap Lake and surrounding watershed were also conducted and found 31 species, 15 bivalves (five families) and 16 gastropods (eight families), in the Tonle Sap basin, including three new records for Cambodia (Scaphula minuta, Novaculina siamensis, Wattebledia siamensis), the presence of globally invasive Pomacea maculata and potential pest species like Limnoperna fortunei. This study represents the most comprehensive documentation of freshwater molluscs of the Tonle Sap basin, and voucher specimens deposited at the Inland Fisheries Research and Development Institute, Cambodia, represent the first known reference collection of freshwater molluscs in the country. In order to combat the combined anthropogenic pressures, including invasive species, climate change and dams along the Mekong River, a multi-pronged approach is urgently required to study the biodiversity, ecology, ecosystem functioning of freshwater molluscs and other aquatic fauna in the Tonle Sap basin.

Identificación molecular y relaciones evolutivas de Pomacea nobilis, base para la autenticación específica del churo negro de la Amazonia peruana

En la Amazonia Peruana los caracoles dulceacuícolas de la familia Ampullariidae son conocidos como churos y originalmente han sido descritas para Perú alrededor de 20 especies. Aunque son muy usadas para alimentación, medicina tradicional y objeto de muchos estudios para su cultivo e industrialización, solamente es mencionada en la literatura la especie Pomacea maculata. Se llevó a cabo la identificación molecular sobre la base del marcador mitocondrial COI, de individuos de churos negros (Pomacea) comercializados en los mercados de Iquitos, así como los usados en platos a la carta en la ciudad de Lima, contrastados con otros individuos de procedencia de su hábitat natural. Se encontró que estos especímenes expendidos corresponden a la especie Pomacea nobilis (Reeve, 1856). El análisis filogenético molecular mostró que P. nobilis es especie hermana de P. guyanensis, en el grupo de P. glauca, distantemente relacionada de P. maculata. Las distancias no corregidas encontradas entre ellas, para el marcador mitocondrial COI, fueron de 11.33% a 13.17%, mientras que con P. maculata fueron de 13.67% a 15.33%. Estos resultados demostraron la eficacia del código de barras de ADN para la identificación y autenticación de la especie, lo que le da un valor agregado para su eventual comercio de exportación.