Stunting of the penis in Heleobia parchappii (Mollusca: Cochliopidae) and its relationship with parasitism

Penis anatomy is used to discriminate species of gastropods belonging to the family Cochliopidae; however, this characteristic may be affected by the presence of parasites. To evaluate the possible effect of parasites on penis length and number of papillae in Heleobia parchappii, 195 males were collected from the Nahuel Rucá Lagoon, Argentina. Male snails were only infected by trematode digeneans (total prevalence 45.13%). Three out of 9 species of digeneans registered showed prevalence values higher than 10%: Microphallus szidati, M. simillimus, and Notocotylidae sp. 1. The penis length of non-parasitized males and those parasitized by M. szidati and M. similimus increased with increased snail length; however, this increase was lower in infected snails. In the case of snails infected with Notocotylidae sp. 1, no relationship between shell length and penis length was apparent. Differences in the life cycles of these 3 digeneans could explain the null or lower penis growth rate in relation to host body growth. In contrast, no change was observed in the number of penial papillae of H. parchappii when these snails were infected by larval digeneans compared to those that were not infected. This indicates that penial papillae may be a more stable characteristic than penis length to discriminate between species within the Cochliopidae. The study of penial papillae should be central in the taxonomy and identification of new species within the Cochliopidae, as well as in previously described species.Fil: Merlo, Matias Javier. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología. Laboratorio de Parasitología; ArgentinaFil: Parietti, Manuela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología. Laboratorio de Parasitología; ArgentinaFil: Etchegoin, Jorge Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología. Laboratorio de Parasitología; Argentin

Una contribución molecular al controvertido estatus taxonómico de un grupo de caracoles dulceacuícolas (Caenogastropoda: Rissooidea, Cochliopidae) distribuídos desde el desierto de los Andes centrales hasta la Patagonia

For over 40 years malacologists have been discussing the taxonomical status of Heleobia species, an enigmatie genus from Cochliopidae family (Caenogastropoda: Rissooidea). As with other rissooidean families, the considerable character convergence and the paucity of anatomical synapomorphies has proved to be a problem in resolving cochliopid phylogenetic relations and establishing the validity of several nominal cochliopid species. Here we present a molecular contribution to solve the taxonomical status of one of the most abundant Southern South América cochliopid genera which has many endemic species. We report molecular evidence that supports three of the four Heleobia groups described for this región, the “australis”, “parchappii” and “piscium” groups. The fourth, the “hatcheri” group, belongs not to Heleobia but to a different genus which itself should not be considered as part of the family Cochliopidae but closely related to genus Potamolithus Pilsbry & Rush, 1896.Durante más de 40 años se ha discutido el estatus taxonómico de diversas especies del enigmático género Heleobia de la Familia Cochliopidae (Caenogastropoda: Rissooidea). Como sucede con otras familias de rissooideos, la abundancia de caracteres convergentes y la escasez de sinapomorfías anatómicas han representado un problema para resolver las relaciones filogenéticas de Cochliopidae y definir la validez de varias de las especies nominales de esta Familia. Presentamos aquí una contribución molecular tendiente a resolver el estatus taxonómico de uno de los más abundantes géneros de la porción meridional de Sudamérica que incluye varias especies endémicas. Nuestra evidencia molecular reconfirma tres de los cuatro grupos de Heleobia en los que se han agrupado las especies del género en esta región: “australis”, “parchappii” y “piscium”. El cuarto, el grupo “hatcheri ”, no pertenece a Heleobia sino a un género diferente que no debería ser considerado como integrante de la Familia Cochliopidae, sino estrechamente relacionado al género Potamolithus Pilsbry y Rush, 1896.Facultad de Ciencias Naturales y Muse

A new species of stygobitic snail in the genus Antrorbis Hershler & Thompson, 1990 (Gastropoda, Cochliopidae) from the Appalachian Valley and Ridge of eastern Tennessee, USA

A new species of cave snail (Littorinimorpha: Cochliopidae) in the genus Antrorbis is described from the dark zone of two caves in the Appalachian Valley and Ridge province in eastern Tennessee, United States. The Tennessee Cavesnail, Antrorbis tennesseensis Perez, Shoobs, Gladstone, & Niemiller, sp. nov. is distinguished from its only known congener, Antrorbis breweri, by the absence of raised tubercles on its finely spirally striate protoconch, and its unique radular formula. Moreover, A. tennesseensis is genetically distinct from A. breweri based on substantial divergence at the mitochondrial CO1 locus. This is the first cavesnail to be described from the Appalachian Valley and Ridge (AVR) physiographic province in the state of Tennessee, which previously represented a substantial gap in the distribution of stygobitic (i.e., aquatic, subterranean-obligate) gastropods

Histology and gametogenesis in Heleobia piscium (Cochliopidae) from the Multiple Use Reserve ‘‘Isla Martín García,’’ Buenos Aires, Argentina

Heleobia piscium (d’Orbigny, 1835), a member of the Cochliopidae family found only in South America, is distributed from Entre Ríos, Delta del Paraná, and the littoral of the Río de la Plata down as far as to Punta Indio (Buenos Aires), the southernmost limit of the snail’s geographical distribution. To date, little information is available regarding the reproductive cycle of species within this family either in Argentina or throughout South America. The present work analyzed the histology of the reproductive system of the gonochoric species H. piscium and determined the stages oogenesis and spermatogenesis under natural conditions. Specimens of H. piscium were collected in the Multiple-Use Natural Reserve Isla Martín García, located in the Upper Río de la Plata estuary to the south of the mouth of the Uruguay River. The gametogenic cycle in both sexes was found to consist of the following stages: early maturation, maturation, and evacuation. The maturation period was found to extend from January to October and evacuation of the gametes to start in November and end in February (summer in the Southern Hemisphere). The results indicated the H. piscium exhibit a reproductive cycle without a resting period

Histology and gametogenesis in Heleobia piscium (Cochliopidae) from the Multiple Use Reserve "Isla Martín García", Buenos Aires, Argentina

Heleobia piscium (d'Orbigny, 1835), a member of the Cochliopidae family found only in South America, is distributed from Entre Ríos, Delta del Paraná, and the littoral of the Río de la Plata down as far as to Punta Indio (Buenos Aires), the southernmost limit of the snail's geographical distribution. To date, little information is available regarding the reproductive cycle of species within this family either in Argentina or throughout South America. The present work analyzed the histology of the reproductive system of the gonochoric species H. piscium and determined the stages oogenesis and spermatogenesis under natural conditions. Specimens of H. piscium were collected in the Multiple-Use Natural Reserve Isla Martín García, located in the Upper Río de la Plata estuary to the south of the mouth of the Uruguay River. The gametogenic cycle in both sexes was found to consist of the following stages: early maturation, maturation, and evacuation. The maturation period was found to extend from January to October and evacuation of the gametes to start in November and end in February (summer in the Southern Hemisphere). The results indicated the H. piscium exhibit a reproductive cycle without a resting period.Facultad de Ciencias Naturales y Muse

Mesohabitat Associations Of The Devil Tryonia, Tryonia Diaboli (Gastropoda: Truncatelloidea: Cochliopidae)

The Cochliopidae of Texas include both stygobitic species, those that occupy only underground habitats, and epigean species, those living only in aboveground habitats. The devil tryonia, Tryonia diaboli, was described from the Devils River of Texas from river wrack, without additional habitat information. This species has been largely ignored since its description, so details of its habitat and ecology are obscure. In Dolan Springs and Finegan Springs, flowing into the Devils River, we sampled macroinvertebrates at five sites that form a gradient from the aquifer to the mainstem Devils River. We found the highest abundances of T. diaboli in aquifer samples, decreasing sharply downstream from the spring orifice. Our findings indicate that T. diaboli is stygophilic, occupying a transitional area including the aquifer as well as aboveground portions of springs

Estudio a largo plazo del ciclo de vida y crecimiento de Heleobia australis (Caenogastropoda, Cochliopidae) en el estuario de Bahía Blanca, Argentina

The life cycle and growth of the mud-snail Heleobia australis (d?Orbigny, 1835) was studied in the Bahía Blanca estuary (39º S, Argentina) from april 2008 to april 2010. Four year classes were identified. H. australis recruits once a year, during summer. In general, the recruits (< 2.5 mm) represented a small percentage of the total population abundance. The growth rate of H. australis declined with increasing animal size. Growth rate for the population under study shows a marked seasonal pattern: lower rate during winter and higher rate in summer. The obtained information allows us to estimate a life cycle of approximately 30 months (~ 2.5 years) for the population of H. australis in Bahía Blanca estuary. This work constitutes the first long term study of the life cycle of cochliopids. As H. australis appears to be a long-lived species which exhibits variations in life cycle that seem to be influenced by biological and physical variables, future studies should incorporate a number of factors, to better understand variations in life-history traits.El crecimiento y ciclo de vida del caracol Heleobia australis fue estudiado en el estuario de Bahía Blanca (39º S, Argentina) de abril de 2008 a abril de 2010. Cuatro clases de edad fueron identificadas. Esta especie recluta una vez al año, durante el verano. En general, los reclutas (< 2.5 mm) representan un pequeño porcentaje de la población total. La tasa de crecimiento de H. australis declinó con el incremento del tamaño del animal y mostró un marcado patrón estacional: baja tasa de crecimiento durante el invierno y alta tasa de crecimiento durante el verano. Se estimó un ciclo de vida de aproximadamente 30 meses (~2.5 años) para la población de H. australis en el estuario de Bahía Blanca. Esta población mostró variaciones en las tasas de crecimiento, la abundancia de reclutas y el tamaño de la conchilla en relación con las poblaciones localizadas al norte. Varios factores como parasitismo, depredación, características ambientales y la acción antropogénica pueden estar interactuando para producir las diferencias observadas. Este trabajo constituye el primer estudio a largo plazo del ciclo de vida de cocliópidos. Heleobia australis parece ser una especie longeva y muestra variaciones en su ciclo de vida que parecen estar influenciadas por variables físicas y biológicas. Estudios a largo plazo que incluyan interacciones biológicas y características espaciales de los microhábitats son necesarios para dilucidar patrones en la historia de vida de H. australis a lo largo de su inervalo de distribución.Fil: Carcedo, Maria Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; ArgentinaFil: Fiori, Sandra Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentin

A new species of stygobitic snail in the genus Antrorbis Hershler & Thompson, 1990 (Gastropoda, Cochliopidae) from the Appalachian Valley and Ridge of eastern Tennessee, USA

A new species of cave snail (Littorinimorpha: Cochliopidae) in the genus Antrorbis is described from the dark zone of two caves in the Appalachian Valley and Ridge province in eastern Tennessee, United States. The Tennessee Cavesnail, Antrorbis tennesseensis Perez, Shoobs, Gladstone, & Niemiller, sp. nov. is distinguished from its only known congener, Antrorbis breweri, by the absence of raised tubercles on its finely spirally striate protoconch, and its unique radular formula. Moreover, A. tennesseensis is genetically distinct from A. breweri based on substantial divergence at the mitochondrial CO1 locus. This is the first cavesnail to be described from the Appalachian Valley and Ridge (AVR) physiographic province in the state of Tennessee, which previously represented a substantial gap in the distribution of stygobitic (i.e., aquatic, subterranean-obligate) gastropods

Larval trematodes infecting the South-American intertidal mud snail Heleobia australis (Rissooidea: Cochliopidae)

Larval trematodes infecting the snail Heleobia australis (Cochliopidae) from the Bahía Blanca estuary, Argentina were surveyed for two years. A total of 7,504 snail specimens was dissected and the larval stages of 15 different trematodes were recovered and examined morphologically. These larvae included four species that had previously been reported from H. australis in Brazil, Uruguay, and Argentina: the heterophyid Ascocotyle (Phagicola) longa and the microphallids, Maritrema bonaerense, Maritrema orensense, and Microphallus simillimus. Three other species, the echinostomatid Stephanoprora uruguayensis, the microphallid Levinseniella cruzi, and the psilostomid Psilochasmus oxyurus are reported here for the first time as parasites of H. australis. Eight other trematodes found in H. australis are described and placed in the appropriate superfamilies, families or genera (Cryptogonimidae, Apocreadiidae, Aporocotylidae, Notocotylidae, Haploporidae, Renicolidae, Himasthla, and Renicola). The prevalence of the trematode taxa infecting H. australis in the Bahía Blanca estuary was low (20%). Microphallidae were the richest and the most prevalent family, probably because of the high abundance of crabs — the second-intermediate hosts of certain microphallid species — and the considerable diversity of gulls. Here we compare the parasite assemblage found in the H. australis from Bahía Blanca estuary with other parasite assemblages infecting Heleobia spp. and other rissooids from the rest of the world.Fil: Alda, Maria del Pilar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Martorelli, Sergio Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; Argentin

Estudio a largo plazo del ciclo de vida y crecimiento de Heleobia australis (Caenogastropoda, Cochliopidae) en el estuario de Bahía Blanca, Argentina

The life cycle and growth of the mud-snail Heleobia australis (d?Orbigny, 1835) was studied in the Bahía Blanca estuary (39º S, Argentina) from april 2008 to april 2010. Four year classes were identified. H. australis recruits once a year, during summer. In general, the recruits (< 2.5 mm) represented a small percentage of the total population abundance. The growth rate of H. australis declined with increasing animal size. Growth rate for the population under study shows a marked seasonal pattern: lower rate during winter and higher rate in summer. The obtained information allows us to estimate a life cycle of approximately 30 months (~ 2.5 years) for the population of H. australis in Bahía Blanca estuary. This work constitutes the first long term study of the life cycle of cochliopids. As H. australis appears to be a long-lived species which exhibits variations in life cycle that seem to be influenced by biological and physical variables, future studies should incorporate a number of factors, to better understand variations in life-history traits.El crecimiento y ciclo de vida del caracol Heleobia australis fue estudiado en el estuario de Bahía Blanca (39º S, Argentina) de abril de 2008 a abril de 2010. Cuatro clases de edad fueron identificadas. Esta especie recluta una vez al año, durante el verano. En general, los reclutas (< 2.5 mm) representan un pequeño porcentaje de la población total. La tasa de crecimiento de H. australis declinó con el incremento del tamaño del animal y mostró un marcado patrón estacional: baja tasa de crecimiento durante el invierno y alta tasa de crecimiento durante el verano. Se estimó un ciclo de vida de aproximadamente 30 meses (~2.5 años) para la población de H. australis en el estuario de Bahía Blanca. Esta población mostró variaciones en las tasas de crecimiento, la abundancia de reclutas y el tamaño de la conchilla en relación con las poblaciones localizadas al norte. Varios factores como parasitismo, depredación, características ambientales y la acción antropogénica pueden estar interactuando para producir las diferencias observadas. Este trabajo constituye el primer estudio a largo plazo del ciclo de vida de cocliópidos. Heleobia australis parece ser una especie longeva y muestra variaciones en su ciclo de vida que parecen estar influenciadas por variables físicas y biológicas. Estudios a largo plazo que incluyan interacciones biológicas y características espaciales de los microhábitats son necesarios para dilucidar patrones en la historia de vida de H. australis a lo largo de su inervalo de distribución.Fil: Carcedo, Maria Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; ArgentinaFil: Fiori, Sandra Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentin