Blatticola chydaeus n. sp. (Nematoda, Thelastomatidae), parasitizing Anurogryllus muticus (De Geer, 1773) (Orthoptera, Gryllidae) in Argentina is morphometric and cytognetic described. It characterized by the female with cuticle annulated up to the middle of the body, the mouth surrounded by eight cephalic papillae, the stoma short with two plates and one tooth, the amphid pore shaped, the oesophagus divided into three parts, anterior cylindrical corpus, isthmus distinct, and basal bulb valvated, the excretory pore located posterior to basal bulb, the nerve ring situated at the beginning of the esophagic isthmus, the intestine broadest anteriorly, the egg oval, smooth shell, in apical view show a triangular section. The tail appendage is short and conic, and presents anal alae. The vulva is protruding, the vagina is long and posterior. The male has one preanal papilla, one simple papilla...

A new species Proparasitylenchus inalienatus sp. n. is described and illustrated, a parasite of the coccinelid Harmonia axyridis Pallas, 1773 in a locality near Gran La Plata, Colonia Urquiza, Argentina. Of the 13 species described, this species,  it  is characterized by having a cephalic end projecting, faint stylet in its normal place, vulva posterior, tail appendage conoid, with bifurcated tip in both sexes, male with two spicules and a tiny gubernaculum, and leptoderan bursa. We obtained the 18S rDNA partial sequence.

The discovery of nematodes in spiders and scorpions from a manual sampling in the city of La Plata, Argentina, revealed the presence of specimens of the order Rhabditda. The main objective of this study is to present the presence of nematodes in the arachnid group, for which there is little precedent. One of the nematodes found belongs to the genus Rhabditis Dujardin, 1845, of saprophytic character, characterized by carrying a fungus that kills the host and degrades it in order to feed itself. This was found in the general cavity of the body of the spider Dysdera crocata Koch, 1838. It is characterized by having a thin cuticle, closed labial papillae, a long stoma without teeth, an esophagus with a middle bulb with a valve and a valved basal bulb, and a middle vulva, short and conical caudal appendage. Mitotic division is described and information about the morphology of chromosomes is p...

Parasitylenchus pseusobifurcatus sp.n. ( Tylenchida, Allantonematidae) is described for the first time for Argentina as a parasite of adults of Harmonia axyridis (Pallas, 1773) (Coleopera, Coccinellidae). The new species is closed to P. bifurcatus Poinar Jr. & Steenberg, 2012, by the characteristic of having the tail tip of all vermiform females and immature males bifurcated, but they differ by the size of the gubernaculum. Its karyotype formula is described. Publicación registrada en Zoobank:LSIDurn:lsid:zoobank.org:pub:751C7C95-EDD7-4D3F-80FA-0BBC5339E404 Acto nomenclatural:LSIDurn:lsid:zoobank.org:act:31912097-A9DF-47C5-9294-2E9DEA879AED

Se cita y describe por primera vez para Argentina Parasitylenchus pseusobifurcatus sp.n. (Tylenchida, Allantonematidae), parásito de adultos de Harmonia axyridis (Pallas, 1773) (Coleopera, Coccinellidae). Esta nueva especie está muy cercana a P. bifurcatus Poinar Jr. y Steenberg, 2012, por la característica de tener todas las hembras vermiformes y los machos inmaduros la punta del apéndice caudal bifurcada, pero se diferencian entre otros por el tamaño del gubernáculo. Se describe su fórmula cariotípica. Publicación registrada en Zoobank:LSIDurn:lsid:zoobank.org:pub:751C7C95-EDD7-4D3F-80FA-0BBC5339E404 Acto nomenclatural:LSIDurn:lsid:zoobank.org:act:31912097-A9DF-47C5-9294-2E9DEA879AED

In the city of La Plata occurs the genus Tityus with records dating back to 1943. The territorial distribution of the genus Tityus in this city and its expansion was studied based on inquiries received at the CEPAVE Arachnology Laboratory from individuals and public and private institutions. 189 inquiries were received from 2005 to 2020. The QGIS program was used to geolocate each scorpion with urban layout layers and storm drains. For the spatial analysis of distribution, a home range of one hectare per individual was considered to calculate the area and in the cases of areas of overlapping influences during the same year, the area was considered as their union. The genus Tityus in the city of La Plata is represented by the species T. carrilloi and T. confluens, both of health interest and of synanthropic habits, which occupy two different well-defined areas. The analysis of the indepen...