Abstract Lichens are symbiotic organisms, usually composed of a fungal partner, the mycobiont, and one or more photosynthetic partners, the photobiont, which is most often either a green alga or a cyanobacterium, that harbor a diverse community of invertebrates such as rotifers, tardigrades, mites, springtails, crustaceans, and nematodes. In this work, we isolated the nematode Geraldius galapagoensis (Chambersiellidae) associated with the lichen Hyperphyscia syncolla (Physciaceae) in a region of Buenos Aires Province, Argentina. This species was discovered in a tropical forest of Ecuador and is characterized mainly by a head offset by a constriction from the rest of the body, a esophagus with a cylindrical pharyngeal corpus without a median bulb, a narrow isthmus and an oval basal pharyngeal bulb with strong transverse/butterfly valve apparatus, a tail curved ventrally, ending in dorsally hooked end; the male with seven pairs of latero-ventral pre-anal papillae and three pairs of post-anal in the following positions: one pair latero-ventral and two pairs dorso-lateral and two slightly curved spicules with asymmetric manubrium with an anterior extension. The comparison of the morphometrics of our G. galapagoensis male with that of the original description shows that the body length is shorter, as are the distance of the excretory pore to the anterior end and the tail. On the other hand, the distance from the anterior end to the nerve ring and the esophagus length are greater. The head width, body diameter and spicule length are quite similar. We provide a morphological and morphometrical characterization of a G. galapagoensis second isolate and the first world report of molecular sequences belonging to this species. organisms partner mycobiont partners photobiont cyanobacterium rotifers tardigrades mites springtails crustaceans nematodes work Chambersiellidae (Chambersiellidae Physciaceae (Physciaceae Province Argentina transversebutterfly transverse butterfly apparatus ventrally lateroventral latero ventral preanal pre anal postanal post positions dorsolateral dorso lateral extension G shorter hand greater width similar

Abstract Caenorhabditis elegans is a free-living nematode, belonging to the bacterivorous trophic group. Although it was cited in several countries, in different types of ecosystems and in associations with other organisms, the wild habitats of this nematode have not yet been precisely defined. In Argentina, C. elegans was recently isolated from the hoverfly Allograpta exotica, a voracious predator with potential biological control against aphids in horticultural crops. In this frame, the objectives of this study were (i) to characterize it molecularly and morphologically (ii) to report a wild strain of C. elegans for the first time from Argentina, (iii) to present a new ecological niche by associating it with A. exotica and (iv) to evaluate the pathogenicity against these insects. The results of the morphological and molecular analyses made it possible to determine that the isolated nematode was C. elegans, thus establishing the ARGLP1900 wild strain as the first record of this nematode for Argentina. A new association was described, since there are no records of interaction between C. elegans and A. exotica, providing information on a new ecological niche. The new wild strain found in this work, could be appropriate for comparative genomic studies with other C. elegans strains.

RESUMEN El presente estudio analiza la nematofauna intestinal de los ortópteros Anurogryllus muticus y Neocurtilla claraziana, como parte de un estudio dirigido en la región de La Plata para aislar especies de nematodos en-tomopatógenos. Once especies de nematodos pertenecientes a las familias Thelastomatidae, Travassosine-matidae, Cephalobidae, Rhabditidae y Plectidae fueron reportadas. Porcentajes de parasitismo de 0,31 a 22,71 % fueron observadas siendo Blatticola cristovata y Cephalobellus magalhaesi las especies más prevalentes. Las especies Cephalobium nitidum, Cruznema tripartitum y Plectus parietinus son registradas por primera vez en Argentina. Los resultados de este estudio contribuyen a tener un mejor entendimiento de la biodiversidad de los nematodos parásitos de insectos de la región.

ABSTRACT The present study analyzes the intestinal nematofauna of the orthopteran species Anurogryllus muticus and Neocurtilla claraziana as part of a survey work conducted in pastures from the region of La Plata to isolate entomopathogenic nematode species. Eleven nematode species belonging to the families Thelastomatidae, Travassosinematidae, Cephalobidae, Rhabditidae, and Plectidae are reported. Parasitism percentages from 0.31 to 22.71 % were observed being Blatticola cristovata and Cephalobellus magalhaesi the most prevalent species. Cephalobium nitidum, Cruznema tripartitum, and Plectus parietinus are reported for the first time from Argentina. The findings of the study contribute to a better understanding of the biodiversity status of insect parasitic nematodes of the region.

Abstract: Oxyurid nematodes parasitizing the mole cricket Neoscapteriscus vicinus were isolated in the framework of sampling fields of mole-crickets from the pampean region, in Argentina. In this work, molecular characterization of the 18S rRNA partial sequence of nematodes belonging to the families Thelastomatidae (Cameronia arecoensis Marchissio and Miralles 1987) and Travassosinematidae (Binema korsakowi Sergiev 1923 and Binema klossae, Marchissio and Miralles 1993) were carried out. This is the first world report of sequences belonging to B. klossae and C. arecoensis and first Argentinian report of B. korsakowi sequence. Also, morphological and morphometric features of B. klossae, B. korsakowi and C. arecoensis from Argentinian populations are reported.

Resumen En la región pampeana, provincia de Buenos Aires, Argentina, la horticultura es una de las principales actividades agrícolas. Los plaguicidas biológicos disponibles en el mercado son escasos en el país e inexistentes en base a nematodos. En este trabajo, se caracterizó un nematodo entomopatógeno nativo aislado de la pampa y se evaluó su infectividad y capacidad reproductiva en el insecto de las fresas, Lobiopa insularis. El análisis morfológico y genético-molecular determinó este aislado como el nematodo Heterorhabditis bacteriophora, designado cepa-VEli. Se aisló un fragmento del ADN genómico de 901 pb (acceso GenBank No KJ575524). La nueva cepa fue patógena contra L. insularis. En recipientes de 200 ml con suelo arcilloso autoclavado (100 ml), a concentraciones de 1.000; 5.000 y 10.000 JIs, la mortalidad en larvas varió de 25 a 77 %. A una concentración de 10,000 JIs, la infección fue mayor en larvas y pupas (77 ± 20 % y 64 ± 25 %, respectivamente) que en adultos (2,2 ± 1,1 %). La concentración letal requerida para matar 50 y 90 % de las larvas (CL50 y CL90) después de 10 días fue 2.840 y 23.743 IJs. Se observaron diferencias en los niveles de parasitismo y en el tiempo de emergencia de los JIs entre concentraciones y estadios aunque no en la producción. Heterorhabditis bacteriophora VEli es el primer nematodo entomopatógeno que infecta y mata L. insularis, capaz de completar su ciclo de vida en todas las etapas del escarabajo de la savia de la fresa. Esta disponibilidad permitiría el establecimiento y posterior dispersión de la cepa en los campos de fresa. Por último, este informe constituye la primera presentación de datos sobre la caracterización morfológica, morfométrica y genética molecular de una cepa nativa de nematodos entomopatógenos para la provincia de Buenos Aires, Argentina.

Abstract The pampean region in the Buenos Aires province of Argentina is a major horticultural area. Biological pesticides to control pest insects available in the market are scarce in this country and nonexistent based on entomonematodes. In this paper, we characterized a native entomopathogenic nematode isolated from soil in the pampas, and evaluated its infectivity and reproductive capacity in the strawberry sap beetle Lobiopa insularis. Morphological and molecular-genetic analysis determined this isolate to be a nematode of Heterorhabditis bacteriophora, thereafter designated as the VEli strain. A 901-bp genomic-DNA fragment was isolated (GenBank Accesion No KJ575524). The new strain was pathogenic against L. insularis. In 200 ml containers with autoclaved clay soil (100 ml), at concentrations of 1,000; 5,000 and 10, 000 IJs, mortality in larvae ranged from 25 to 77 %. At a concentration of 10,000 IJs, infectivity was higher in larvae and pupae (77 ± 20% and 64 ± 25 %, respectively) than in adults (2.2 ± 1.1 %). The lethal concentration required to kill 50 and 90 % of the larvae (LC50 and LC90) over 10 days was 2,840 and 23,743 IJs. Differences were observed in the parasitism levels and emergence time of IJs between concentrations and stages, although not for production. Heterorhabditis bacteriophora strain VEli is the first entomopathogenic nematode found to infect and kill L. insularis, capable of completing its life cycle in all strawberry sap beetle stages. This availability would enable the establishment and subsequent dispersal of the strain in strawberry fields. Finally, this report constitutes the first presentation of data on the morphological, morphometric, and molecular-genetic characterization of a native entomopathogenic nematode strain from the Buenos Aires province, Argentina.

Diploscapter coronata is a free-living soil bacterial-feeding nematode found in compost, sewage or agricultural soil and as a facultative parasite of insects and vertebrates, even humans. The clinical symptoms include epigastric tenderness, diarrhea, crampy abdominal pain, weakness and nauseas. Also, they have been considered as potential carriers of bacteria pathogenic to the surface of preharvest fruits and vegetables in contact with soil. In this note, we reported the presence of D. coronata in the framework of diverse soil nematodes samplings in orchards of Abasto town, Buenos Aires province, Argentina. Soil samples taken from tomato growing (Lycopersicon esculentum) were processed in the laboratory by the centrifugation method, while collected roots were observed directly under stereomicroscope in order to isolate nematodes. Specimens were identified by morphological and morphometric characteristics. Results showed the presence of D. coronata in agricultural soil and in association with root galls, caused by the plant-parasitic nematode, Nacobbus aberrans. Females were the only isolated stage. The detection of this nematode in greenhouses where dogs, cats and poultry live together without any health control highlights the importance of applying proper hygiene measures during agricultural practices to avoid contamination of fruits and vegetables and prevent infections in domestic animals and humans. This report constitutes the first record of the Diploscapter genus with the species D. coronata in Argentina.

Diploscapter coronata es un nematodo de vida libre que habita el suelo y se alimenta de bacterias. Se ha encontrado en compost, alcantarillas o suelos agrícolas y como parásito facultativo de insectos y vertebrados, incluyendo al hombre. Los síntomas clínicos incluyen: sensibilidad epigástrica, diarrea, dolor abdominal y náuseas. Incluso, han sido considerados potenciales portadores de bacterias patogénicas asociadas con la superficie de frutas y vegetales pre-cosechadas en contacto con el suelo. En esta nota, se reporta la presencia de D. coronata en el marco de diversos muestreos de nematodos de suelo, en huertas de la localidad de Abasto, provincia de Buenos Aires, Argentina. Las muestras de suelo tomadas de cultivo de tomate (Lycopersicon esculentum) se procesaron en el laboratorio mediante el método de centrifugación, mientras que las raíces recolectadas fueron observadas directamente bajo microscopio estereoscópico con el fin de aislar los nematodos. Los especímenes fueron identificados por características morfológicas y morfométricas. Los resultados mostraron la presencia de D. coronata en suelos agrícolas y en agallas radicales causadas por el nematodo parásito de plantas Nacobbus aberrans. Las hembras fueron el único estadio aislado. La detección de este nematodo en invernaderos donde gatos, perros y aves de corral viven juntos sin ningún control sanitario, realza la importancia de adoptar medidas apropiadas de higiene durante las prácticas agrícolas para evitar la contaminación de frutas y verduras y prevenir infecciones en animales domésticos y el hombre. Este informe constituye el primer registro del género Diploscapter con la especie D. coronata en Argentina.

Oryctophila bonaerensis sp. nov. parasitizing curculionid beetle larvae from Argentina, is described and illustrated. The species is characterized by a prominent genital cone and a short and filiform tail appendage. Female with vulva at midlenght of body, vagina long, S-shaped, monodelphic, opistodelphic. Male with one club-shaped spicule. Genital papillae arranged as follows: one pair of large preanal papillae and three pairs of postanal papillae of various sizes: a pair of medium sized papillae is immediately posterior to the anus, followed by a pair of large papillae, and one pair of small papillae at the base of the caudal appendage.

A new species, Hexamermis paranaense n. sp. (Nematoda, Mermithidae), a parasite of larvae of Diloboderus abderus Sturm, 1826 (Coleoptera, Scarabaeidae) is described and illustrated. This new species is characterized by amphids small, amphidial opening pocket-shaped, the anterior portion of the vagina muscularized and slightly protruding with a descending branch forming a loop before joining the uterus, and three rows of genital papillae: the ventrolateral divided in two rows with eight papillae in the outer row and with six papillae in the inner one; the ventral row with four pairs and one single preanal papillae, and with two pairs, a triplete, one pair, a single and one pair postanal papillae.

Una nueva especie, Hexamermis paranaense sp. nov. (Nematoda, Mermithidae), parásito de larvas del gusano blanco, Diloboderus abderus Sturm, 1826 (Coleoptera, Scarabaeidae), se describe e ilustra. Esta nueva especie se caracteriza por poseer anfidos pequeños, con la apertura en forma de bolsillo, parte anterior de la vagina muscular, con una rama que desciende y forma un lazo antes de la conexión al útero, tres hileras de papilas genitales: la hilera de posición ventro-lateral dividida en dos hileras con ocho papilas en la hilera externa y con seis papilas en la interna; la hilera ventral con una papila, seguida de cuatro pares, todas en posición preanal y dos pares, interrumpidos por tres papilas, seguida de un par, una simple, y un par, todas de posición postanal.

Blatticola cristovata n. sp. (Oxyurida, Thelastomatidae) a parasite of the cricket Anurogryllus muticus (De Geer, 1773) (Orthoptera, Gryllidae) from Argentina, is described and illustrated. This is the first species of the genus Blatticola found parasitizing cricket. This new species is characterized in females by having the cuticle annulated through the body length, the mouth opening is subtriangular and surrounded by eight cephalic papillae, the stoma is short with three pairs placed in two rows of cuticular sclerotised plates, amphids in small pore shaped, oesophagus is divided into three parts, anterior cylindrical corpus, isthmus distinct, and basal bulb valved, the nerve ring is situated around the middle of corpus, the intestine is wide broad anteriorly, oval eggs, smooth shell, with a straight side, and the other side with a band running longitudinally. Males with one pair of preanal, one pair of adanal and two pairs of postanal papillae, and the tail appendage short, conical and pointed.

Una nueva especie Blatticola cristovata n. sp. (Oxyurida, Thelastomatidae) parásita del grillo Anurogryllus muticus (De Geer, 1773) (Orthoptera, Gryllidae) en Argentina, se describe e ilustra. Esta es la primera especie del género Blatticola que se encontró parasitando a grillos. Esta nueva especie se caracteriza por tener las hembras la cutícula anillada a lo largo de todo el cuerpo, la abertura bucal triangular rodeada por ocho papilas cefálicas, el estoma corto con tres pares de placas esclerotizadas dispuestas en dos líneas, anfidios pequeños en forma de poro, esofago dividido en tres partes, una anterior con un corpus cilíndrico, un istmo distintivo, y un bulbo basal con valvas, el anillo nervioso situado rodeando el corpus, el intestino ensanchado anteriormente, huevos ovales, de cáscara lisa, con un lado recto y el otro con una cresta longitudinal. Macho con un par de papilas preanal, uno adanal y dos pares de papilas postanales, y apéndice caudal corto, cónico y punteagudo.