A new species of Plagiodontes from Argentina, and new data on the anatomy of four other species in the genus (Gastropoda: Orthalicidae, Odontostominae)

Plagiodontes weyrauchi sp. nov. is among the smallest species in the genus Plagiodontes (Doering, 1877). Statistical multivariate analyses confirmed its distinctiveness from other species, mostly because of its high number of whorls (8-9.75), relatively small width, and low proportions of last whorl and aperture length to shell length; multivariate discriminant analysis applied to this species and its most similar relative, P. multiplicatus parvus, correctly identified 100% of specimens. Pallial and genital anatomy supports P. weyrauchi as a different species, mainly because of the position of the ureteric pore, the small general size of the genital system, the presence of an accessory lobe alongside the verge, and the vaginal internal structure. Internal anatomy of four other small-sized taxa in the genus was studied. Two of them have a verge with no accessory lobe [P. dentatus (Wood, 1828) and P. patagonicus (d'Orbigny, 1835)], while the remaining two have an accessory lobe with different characteristics [P. rocae Doering, 1881 and P. multiplicatus parvus (Hylton-Scott, 1952)]. Internal structure of the vagina also shows specific differences among Plagiodontes species; their phylogenetic significance will be further investigated.Fil: Piza, Julia. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Laboratorio de Zoología de Invertebrados I; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cazzaniga, Néstor Jorge. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Laboratorio de Zoología de Invertebrados I; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

The freshwater ribbon-worm Prostoma graecense (Hoplonemertea: Monostilifera) in South America (Argentina)

The morphological species Prostoma graecense (Böhmig, 1892) is reported for the first time fromArgentina and South America. Some diagnostic characters, such as the ciliated epithelium of thenon-rhynchodaeal oesophagus and the backward extension of the cephalic glands up to the braincommisure, were confirmed for the Argentine material; the rhynchodaeal longitudinal muscleswere present, but did not form a thick layer as expected from some previous descriptions. AddingSouth America to its distribution range supports the hypothesis that this morphotype Prostomagraecense actuallyhas a cosmopolitan distribution.Fil: Tamburi, Nicolas Eduardo. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; ArgentinaFil: Cazzaniga, Néstor Jorge. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentin

Implanted byssal hairs on postlarval shells of Mytilus edulis platensis (Bivalvia: Mytilidae) from Patagonia

This communication describes the first records of byssal hairs on the postlarvae shells of Mytilus edulis platensis d’Orbigny, 1842. The postlarvae used in this study were sampled on artificial collectors used for mussel culture in San Jorge Gulf, Sudoccidental Atlantic Ocean. A general description of the hairs is made as well as an exploratory analysis of their spatial distribution on the shell surface. The presence of these byssal hairs is suggested as a criterion to differentiate M. edulis platensis from other mytilids.Fil: Isola, Tomá. Universidad Nacional de la Patagonia Austral. Centro de Investigaciones y Transferencia Golfo San Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia Golfo San Jorge. Universidad Nacional de la Patagonia "San Juan Bosco". Centro de Investigaciones y Transferencia Golfo San Jorge; ArgentinaFil: Varisco, Martin Alejandro. Universidad Nacional de la Patagonia Austral. Centro de Investigaciones y Transferencia Golfo San Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia Golfo San Jorge. Universidad Nacional de la Patagonia "San Juan Bosco". Centro de Investigaciones y Transferencia Golfo San Jorge; ArgentinaFil: Cazzaniga, Néstor Jorge. Universidad Nacional del Sur; Argentin

Implanted byssal hairs on postlarval shells of Mytilus edulis platensis (Bivalvia: Mytilidae) from Patagonia

This communication describes the first records of byssal hairs on the postlarvae shells of Mytilus edulis platensis d’Orbigny, 1842. The postlarvae used in this study were sampled on artificial collectors used for mussel culture in San Jorge Gulf, Sudoccidental Atlantic Ocean. A general description of the hairs is made as well as an exploratory analysis of their spatial distribution on the shell surface. The presence of these byssal hairs is suggested as a criterion to differentiate M. edulis platensis from other mytilids.Fil: Isola, Tomá. Universidad Nacional de la Patagonia Austral. Centro de Investigaciones y Transferencia Golfo San Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia Golfo San Jorge. Universidad Nacional de la Patagonia "San Juan Bosco". Centro de Investigaciones y Transferencia Golfo San Jorge; ArgentinaFil: Varisco, Martin Alejandro. Universidad Nacional de la Patagonia Austral. Centro de Investigaciones y Transferencia Golfo San Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia Golfo San Jorge. Universidad Nacional de la Patagonia "San Juan Bosco". Centro de Investigaciones y Transferencia Golfo San Jorge; ArgentinaFil: Cazzaniga, Néstor Jorge. Universidad Nacional del Sur; Argentin

Redescription of Ventania avellanedae (Stylommatophora: Odontostomidae), a land snail endemic to the Ventania Mountain System, Argentina

Although the presence of apertural folds and lamellae is the most recognizable character of the Odontostomidae, some species lack them, mostly in Anctus Martens, 1860, Bahiensis Jousseaume, 1877 and Moricandia Pilsbry & Vanatta, 1898. Eudioptus avellanedae Doering, 1881 - a slender odontostomid species that lacks even the slightest trace of folds or lamellae in its shell aperture - was however transferred to Odontostomus by Pilsbry in 1902 on the basis of its building forward of the aperture-margins. It is currently placed in its own monotypic subgenus, Cyclodontina (Ventania) Parodiz, 1940, on the basis of about the same argument. In this paper we redescribe its shell morphology and, for the first time, describe the internal anatomy of the pallial complex and the reproductive and digestive systems. The presence of a spongy gland in the pallial complex; of a short penis sheath with no retractor muscle; of a bursa copulatrix duct longer than spermoviduct, and of an epiphallic gland strongly support the inclusion of this unusual species in Odontostomidae. The species is diagnosable by the sculpture of the protoconch, which is not smooth as previously described, but has waved axial ribs crossed by spiral lines in young specimens; the distinctive external and internal shape of the bursa copulatrix duct; the internal penis wall divided in three regions of different sculpture; the smooth inner wall of the vagina; the long and cylindrical epiphallus with a distal widening indicating the presence of an epiphallic gland, and the penis retractor muscle inserted in the distal end of a short flagellum. These characters support the validity of Ventania Parodiz, 1940, different from Cyclodontina Beck, 1837.Fil: Piza, Julia. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias Biológicas y Biomédicas del Sur. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Instituto de Ciencias Biológicas y Biomédicas del Sur; ArgentinaFil: Cazzaniga, Néstor Jorge. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentin

New record of the soft-bodied genus Franciscideres (Kinorhyncha) from Argentina, with notes on its movement and morphological variation

Samples collected from Monte Hermoso, Buenos Aires Province, Argentina revealed the presence of specimens of the genus Franciscideres Dal Zotto et al., 2013, previously known only from Brazil. This morphotype seems to differ from the only known species, Franciscideres kalenesos Dal Zotto et al., 2013, in the following characters: (1) presence of ventrolateral tubes on segment 1, (2) introvert features, (3) each segment composed of a closed cuticular ring, (4) trunk cuticle ornamented by a secondary fringe of knob-like structures, (5) posterior margin of segment 10 ventrally terminating in two lateral and one broad triangular lobes, (6) posterior margin of segment 11 centrally terminating in four lobes (7) lateral terminal spines armed with thorn-like processes, (8) pores/sensory spots/gland cells distribution and (9) sexual dimorphism in segments 10 and 11. Because of the lack of full information about F. kalenesos from Brazil, we consider the new exemplars as Franciscideres cf. kalenesos. Additionally, we provide new information about the movement of this species using light microscopy and we compare these movements with those of other meiofaunal inhabitants.Fil: Rucci, Kevin Alen. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; ArgentinaFil: Neuhaus, Birger. Staatliches Museum fur Naturkunde Stuttgart; AlemaniaFil: Bulnes, Verónica Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias Biológicas y Biomédicas del Sur. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Instituto de Ciencias Biológicas y Biomédicas del Sur; ArgentinaFil: Cazzaniga, Néstor Jorge. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentin

An alternative method to assess individual growth of the golden mussel (<i>Limnoperna fortunei</i>) in the wild

The invasive freshwater bivalve Limnoperna fortunei is native to Chinese and Southeast Asian rivers and creeks. The impact of L. fortunei in South America involves both the human and the natural environments. Larvae and juveniles enter water systems of the drinking water plants and cooling systems of industries and power plants where they settle, mature, and produce macrofouling problems. Life cycle studies are undertaken in temperate region plants in order to gather basic information to develop strategies for control of L. fortunei. Individual growth of L. fortunei cohorts using experimental enclosures is recorded. The growth curve obtained shows that L. fortunei grows at a higher rate than recorded previously in works carried out in man-made facilities and natural environments along the coast of the Rı´o de la Plata.Facultad de Ciencias Naturales y MuseoConsejo Nacional de Investigaciones Científicas y Técnica

Systematic evaluation of cryptic freshwater snails from central Chile, including the enigmatic Littoridina santiagensis (Gastropoda, Truncatelloidea)

In 1944, Walter Biese described Littoridina santiagensis (Cochliopidae) from Estero Dehesa based exclusively on external shell features and a second allopatric population in Yeso Spring three years later. Different samplings carried out since 2011 in the type locality have only provided specimens of the morphologically similar invasive mudsnail Potamopyrgus antipodarum (Tateidae) raising doubts about the identity of the species. The recent finding of two snail morphotypes in Yeso Spring, a thick shelled form congruent with type specimens of L. santiagensis and a slender one morphologically associable to P. antipodarum, allowed comparative studies, including the taxonomic analysis of additional populations with similar shell morphology occurring in central Chile. A DNA barcoding (COI) approach identified the slender form from Yeso Spring in Maipo Basin and a second population from the contiguous Rapel Basin indeed as the invasive P. antipodarum, however, L. santiagensis was recovered among species of Potamolithus (Tateidae) justifying the binomem Potamolithus santiagensis as a new combination. Besides recognition of other three populations as belonging to Potamolithus, the molecular analysis also suggests trans-Andean dispersal of this group of snails in the Southern Cone of South America.Fil: Collado, Gonzalo A.. Universidad del Bio Bio; ChileFil: Aguayo, Karina P.. Universidad del Bio Bio; ChileFil: Cazzaniga, Néstor Jorge. Universidad Nacional del Sur; ArgentinaFil: Gutierrez Gregoric, Diego Eduardo. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: de Lucia, Micaela. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Invertebrados; ArgentinaFil: Haase, Martin. University of Greifswald; Alemani

Estudios bio-ecológicos de gasteropodos dulceacuícolas relacionados con la invasión de canales por malezas acuáticas

No se posee.Facultad de Ciencias Naturales y Muse

Informe científico de investigador: Cazzaniga, Néstor Jorge (2015-2016)

Se estudia la variabilidad morfométrica y anatómica de especies autóctonas de invertebrados continentales y estuariales, principalmente del sur de la provincia de Buenos Aires, aportando además información ecológica básica, integrable a planes de manejo de áreas naturales. Se exploran caracteres de posible valor filogenético y técnicas de análisis multivariado que permiten comparaciones y discriminaciones más objetivas. El proyecto incluye tres subproyectos en desarrollo, articulados con los planes de trabajo de becarios e investigadores de carrera bajo dirección del investigador, con el nexo conceptual de la variabilidad intraespecífica y factores ecológicos que la influyen. Las principales líneas corresponden a estudios taxonómicos y de biología reproductiva de Plagiodontes (Gastropoda: Orthalicidae); variabilidad y demografía de Heleobia australis (Gastropoda) en microambientes del estuario de Bahía Blanca, en particular asociada a su carga parasitaria; dinámica y rol de los turbelarios (Platyhelminthes) meiofaunales en la conservación del ecosistema estuarial; caracterización taxonómica de componentes meiofaunales aún desconocidos para la región, en particular Tardigrada, Harpacticoida, Amphipoda y Kinorhyncha, como target temático para la formación de nuevos recursos humanos