Identity of Carex trichodes Steud. ex Boott and Carex lateriflora Phil. (subgen. Psyllophorae, sect. Junciformes, Cyperaceae) from Southern South America

The identity of Carex trichodes, a species only known from the collection of the type material made in 1854 is clarified after finding it in the wild in the vicinity of the type locality. It is concluded that C. trichodes was proposed based on stressed plants corresponding to the same taxon later described as C. lateriflora.

First record of Myocastor coypus (Molina 1782) (Mammalia, Rodentia) for the state of Mato Grosso do Sul, Brazil, and its distribution in southern South America

This study presents the first record of Myocastor coypus in the state of Mato Grosso do Sul, in addition to detailing its distribution within southern South America, highlighting where it is considered native or exotic in Brazil. On April 23, 2018, at approximately 18:00, an adult specimen with a 40 cm BL (body length) was registered after being run over on a side road near wetlands and a dam in a rural area in the municipality of Bataguassu, eastern state of Mato Grosso do Sul. It is not possible to state the origin of the M. coypus reported in the present study; whether it was introduced or dispersed naturally through the flooded areas of the Paraná River, since the species has records on the border of the states of Mato Grosso do Sul and Paraná.

Revision of South American stiletto fly genus Argolepida Metz & Irwin (Diptera: Therevidae: Therevinae)

The stiletto fly genus Argolepida Metz & Irwin, 2003 is revised. Members of this genus are diminutive, yet distinctive, flies restricted to southern South America. Argolepida rivulosa (Kröber, 1928) is redescribed and seven new species are described and figured. A key to species is presented.

Three new genera of large marsh beetles (Coleoptera: Scirtidae) from Valdivian temperate rain forests of southern South America

The present paper fills a gap in the knowledge of the largest marsh beetles in the Neotropics. Argelodes gen. nov., Solierodes gen. nov. and Mucronotus gen. nov. are described from Southern South America. Argelodes and Solierodes are monotypic, contain Argelodes magnificus sp. nov. and Solierodes rousseli (Solier, 1849) comb. nov., while Mucronotus contains five species: Mucronotus velutinus (Solier, 1849) comb. nov., M. schwabei (Pic, 1938) comb. nov., and three newly described ones—M. enigmaticus sp. nov., M. patagonicus sp. nov., and M. valdivianus sp. nov. Affinities of newly described genera with Australian taxa are briefly discussed. Pronotal modifications in marsh beetles are illustrated and discussed.

A new species of Homonota (Squamata: Gekkota: Phyllodactylidae) from Paraguay

The 12 recognized species of the genus Homonota are geographically restricted to central and southern South America in Argentina, Brazil, Uruguay, Bolivia, and Paraguay. The phylogenetic relationships within the genus are well known where three groups are identified, each of them containing four species: the whitii group (Homonota darwinii, H. williamsii, H. whitii, and H. andicola), the borellii group (H. borellii, H. taragui, H. rupicola, and H. uruguayensis) and the horrida group (H. horrida, H. underwoodi, H. septentrionalis, and H. marthae). During fieldwork in Paraguay, we found a specimen of Homonota with unique morphological and geographical traits. Thus, we performed a comparative morphological analysis against specimens housed in different Paraguayan collections. Additionally, we performed a DNA analysis of our specimen to assess its relationships within the genus. Results suggest that this specimen represents a new species of the Homonota horrida group based on molecular and morphological evidence. The new species is characterized by a robust body, 10 longitudinal rows of strongly keeled scales separated by one or two granular scales, square-shaped mental scales, small postmental scales, one or two rows of rectangular scales in the upper eye scales, rostral scale divided, edge of auditory meatus serrated posteriorly, and black and brown background coloration with one white vertebral line and seven white transverse bands. The new species is restricted to Paraguarí Department, characterized by herbaceous grasslands with rocky outcrops.

A Late Cretaceous dinosaur and crocodyliform faunal association–based on isolate teeth and osteoderms–at Cerro Fortaleza Formation (Campanian-Maastrichtian) type locality, Santa Cruz, Argentina

The Late Cretaceous dinosaur record in southern South America has been improved recently; particularly with findings from Chorrillo and Cerro Fortaleza formations, both bearing ankylosaur remains, a clade that was not previously recorded in the Austral Basin. The dinosaur fauna of the type locality of Cerro Fortaleza Formation is known from -and biased to- large-sized sauropod remains and a single described taxon, the titanosaur Dreadnoughtus schrani. Here, we report the taxonomic composition of a site preserving thirteen isolated teeth and several osteoderms belonging to three dinosaur clades (Abelisauridae, Titanosauria, and Nodosauridae), and at least one clade of notosuchian crocodyliforms (Peirosauridae). They come from sediments positioned at the mid-section of the Cerro Fortaleza Formation, which is Campanian-Maastrichtian in age, adding valuable information to the abundance and biodiversity of this Cretaceous ecosystem. Since non-titanosaur dinosaur bones are almost absent in the locality, the teeth presented here provide a window onto the archosaur biodiversity of the Late Cretaceous in southern Patagonia. The nodosaurid tooth and small armor ossicles represent the first record of ankylosaurs for this stratigraphic unit. The peirosaurid material also represents the most austral record of the clade in South America.