Stenoterommata iguazu is a species of mygalomorph spiders of Argentina, named after its type locality: Iguazú, Misiones. Females are distinguished from other species in the genus, except S. platense, by the 2 + 2 spermathecae; from S. platense, they are distinguished by the outer spermathecal lobe having a single receptaculum. Males are distinguished from other species, except S. platense, by having a thin, well-sclerotized embolus and the bulbal duct with an even curvature; from S. platense, by the sudden tapering apical portion of the bulbal duct and the slightly smaller size.
Stenoterommata crassistyla is a species of mygalomorph spiders of Argentina, named after its wide embolus (stylus) in males, distinguishing this species from the sympatric S. tenuistyla. Its behaviour is similar to the latter species as well. Females are distinguished from other Stenoterommata having multireceptaculate spermathecae by the presence of inferior tarsal claws on the anterior legs. Males have the palpal tibia with a basal notch at either side of the base, and swollen. The species is distinguished from S. tenuistyla by lacking the short spines on the male metatarsus I, characteristic of said species.
Acanthogonatus confusus is a mygalomorph spider of Argentina and Chile, its name referring to the confusion between this species and A. subcalpeianus. Males are recognized by their long palpi, together with the absence of a tibial apophysis; females are recognized by the spermathecae.
Acanthogonatus huaquen is a mygalomorph spider of Chile, its name referring to its type locality: Huaquén, Chile. Males are recognized from other two-clawed Acanthogonatus by the bulb with a lateral keel delimiting a concave area; females by the spermathecae with an almost conical basal mound and its duct arising from its tip.
Acanthogonatus quilocura is a mygalomorph spider of Chile, its name referring to the seemingly unending number of species within this genus. Males are similar to those of A. tacuariensis, from which are distinguished by a curved metatarsus I; female spermathecae are characteristic in having a strongly bent duct arising from the base of a blunt basal dome.
Acanthogonatus centralis is a mygalomorph spider of Argentina, its name referring to its distribution, being one of the most common mygalomorphs in central Argentina. Females are most similar to those of A. parana, are distinguished by the widened fundus of the spermathecae. Males, on the other hand, are recognized by the smooth, keelless bulb, in combination with a well-developed tibial apophysis.
Acanthogonatus parana is a mygalomorph spider of Argentina, its name referring to its type locality: Paraná, Entre Ríos. Females are most similar to those of A. centralis, but are distinguished by the narrow fundus of the spermathecae.
Acanthogonatus alegre is a mygalomorph spider of Chile, its name using the Spanish word for “happy”, referring to the aspect of a happy face that the female epigastrium has in posterior view. Females are recognized by the epigastrium produced in a membranous extension and the long, slender and bifurcated spermathecae.
Acanthogonatus recinto is a mygalomorph spider of Chile, its name arising from its type locality: Recinto, Nuble, Region VIII, Chile. Females are distinguished from those of A. franki by the spermathecae, having a more rounded and differentiated fundus and its basal portion extended internally, compared to those of A. peniasco with a narrower, longer and less sclerotized ducts; and from other species in the genus by having 1-1-1 P spines on its patella IV. Males differ from those of A.franki in the unique winglike projection at the base of the embolus.
Acanthogonatus peniasco is a mygalomorph spider of Chile, its name arising from its type locality: El Peñasco, Linares, VII Region, Chile. Females differ from those of A. franki and A. recinto in the shorter, wider, and more sclerotized spermathecal ducts, and from those of other species in the genus by having 1-1-1 P spines in the patella IV.
Acanthogonatus nahuelbuta is a mygalomorph spider of Chile, named after its type locality: Piedra del Águila, Parque Nacional Nahuel-Buta, Malleco. Males differ from A. patagallina by having the basal portion of the bulb less rounded and the basal loop of the bulbal duct less sinuous; and from those of A. hualpen by the differently shaped embolus and the palpal tibia with the apical two-thirds tapering gradually and having thickened setae.
Acanthogonatus hualpen is a mygalomorph spider of Chile, named after its type locality: Hualpén, Concepción, Bío Bío Region. Males can be distinguished from those of A. nahuelbuta and A. patagallina by the shaped of the bulb's apex, and by the palpal tibia being wide in the basal two-thirds with thickened setae along the apical one-third of the retrolateral face.
Acanthogonatus patagallina is a mygalomorph spider of Chile, named after its type locality: Pata de Gallina, Arauco, Region VIII. This species is closest to A. nahuelbuta, but is distinguished by having the basal portion of the male's bulbal duct more sinuous and the basal portion of its bulb more rounded in lateral view.
Acanthogonatus vilches is a mygalomorph spider of Chile, named after its type locality: Gil de Vilches, Talca, Region VII. Females differ from other species in the nahuelbuta group by their less modified spermathecae.
Acanthogonatus mulchen is a mygalomorph spider of Chile, named after its type locality: Alto Caledonia, east of Mulchén, Region VIII. It is recognised by the long, narrow sternum. It differs from A. tolhuaca in the spermathecae having a less pronounced notch and the glandular areas on each side joining in the middle. It is larger, and differs from A. brunneus by its uniformly colored abdomen.
Acanthogonatus tolhuaca is a mygalomorph spider of Chile, named after its type locality: Tolhuaca, Malleco, Region IX. This species differs from A. mulchen in its wider sternum, smaller size, and the spermathecae having a more pronounced notch; from A. brunneus, it differs in the uniformly coloured abdomen.
Chilelopsis puertoviejo is a species of mygalomorph spiders of Chile, named after its type locality: Puerto Viejo, Copiapó, Region III. The species is most similar to C. calderoni, but differs in having the distal portion of the male bulbal duct less sinuous and the female spermathecae of uniform width, with no differentiated fundus. It differs from C. serena in the undivided female spermathecae and the male tibia I having a dense apical patch of setae.
Lycinus tofo is a mygalomorph spider of Chile, named after its type locality: El Tofo, Coquimbo Region. Males are distinguished by the palpal bulb, more abruptly tapered than in other species of the genus; females by the long, slender, spiraled spermathecal receptacula.
Chaco sanjuanina is a species of mygalomorph spiders of Argentina, named after its type locality: San Agustin, Valle Fertil, San Juan, Argentina. Males can be distinguished from those of its cogenerates by the more conical bulb; females differ from C. tecka in having fewer spines on the metatarsus IV, and from C. patagonica in having labial cuspules arranged in a transverse row and the more numerous maxillary ones.
Chaco tecka is a species of mygalomorph spiders of Argentina, named after its type locality: Rio Tecka, Chubut, Argentina. Females can be distinguished from those of other species of Chaco by the strong and numerous spines on metatarsus IV and by the presence of pseudopreening combs on metatarsi III and IV. From C. patagonica and C. sanjuanina, females differ also in the patterned cephalothorax and legs.
