A new fossil rodent assemblage from the Solimões Formation (upper Miocene), Acre, Brazil

International audienceCaviomorpha is a South American hystricognath clade with great taxonomic and phenotypic diversity. Their stratigraphic distribution ranges from the middle Eocene to the present times. In the Solimões Formation, northern Brazil, a rich Neogene fossil record has been documented over the last years. Here, we report preliminary data about a new fossiliferous assemblage recovered in recent fieldwork in the Envira River, State of Acre, Brazil. The specimens were recovered in 2010 and 2019 from Neogene sedimentary strata exposed in this river. The fossils were found using a screen-washing method with an aqueous hydrogen peroxide solution and subsequent screening in a stereoscopic magnifying glass. After these procedures, the specimens are being scanned with a micro-CT. The preliminary analysis identified a mandible with premolar and molars and many isolated molariform teeth. Our results suggest the presence of Octodontoidea (including Acarechimys-like), Erethizontoidea, Chinchilloidea (Scleromys-like dinomyids and a potamarchine; and Neoepiblemidae), and Cavioidea (Hydrochoerinae). Based on previous records of Solimões Formation, the presence of potamarchines, neoepiblemids, and hydrochoerines is in accordance with a late Miocene age for these strata (typical Acre fauna). Although fossils have not yet been identified at a less inclusive level, it is possible to observe that this is the most diverse assemblage of Neogene rodents from the Brazilian Amazon

A new fossil rodent assemblage from the Solimões Formation (upper Miocene), Acre, Brazil

International audienceCaviomorpha is a South American hystricognath clade with great taxonomic and phenotypic diversity. Their stratigraphic distribution ranges from the middle Eocene to the present times. In the Solimões Formation, northern Brazil, a rich Neogene fossil record has been documented over the last years. Here, we report preliminary data about a new fossiliferous assemblage recovered in recent fieldwork in the Envira River, State of Acre, Brazil. The specimens were recovered in 2010 and 2019 from Neogene sedimentary strata exposed in this river. The fossils were found using a screen-washing method with an aqueous hydrogen peroxide solution and subsequent screening in a stereoscopic magnifying glass. After these procedures, the specimens are being scanned with a micro-CT. The preliminary analysis identified a mandible with premolar and molars and many isolated molariform teeth. Our results suggest the presence of Octodontoidea (including Acarechimys-like), Erethizontoidea, Chinchilloidea (Scleromys-like dinomyids and a potamarchine; and Neoepiblemidae), and Cavioidea (Hydrochoerinae). Based on previous records of Solimões Formation, the presence of potamarchines, neoepiblemids, and hydrochoerines is in accordance with a late Miocene age for these strata (typical Acre fauna). Although fossils have not yet been identified at a less inclusive level, it is possible to observe that this is the most diverse assemblage of Neogene rodents from the Brazilian Amazon

New records of marsupials from the Miocene of Western Amazonia, Acre, Brazil

The Amazonian region covers a significant part of the South American continent and harbors outstanding biodiversity. However, much of its history is still unknown. This situation has begun to change with paleontological field efforts over the last decades, which have been proving that fossils can be common in this region. Despite their great current species richness and abundance in the area today, marsupials have a sparse fossil record, restricted to a few specimens from handful Cenozoic Amazonian localities. Here we present new records of fossil marsupial teeth from the Solimões Formation (lower Eocene–Pliocene), on the Juruá and Envira riverbanks (Acre, Northwestern Brazil). The localities investigated yield at least four distinct didelphid didelphimorphians at PRE 06 (Ponto Rio Envira: Marmosini ?Marmosa sp., Didelphis cf. D. solimoensis, Thylamys? colombianus, plus unidentified didelphids), and two paucituberculatans from the Juruá River localities (Ponto Rio Juruá: the palaeothentid Palaeothentinae indet. at PRJ 25 and PRJ 33’, and Abderitidae indet. from PRJ 33). In agreement with the associated mammalian faunas, most of the didelphids, except for Thylamys? colombianus from PRE 06, indicate a (?early) Late Miocene age for this locality. Conversely, the abderitid specimens found in situ at PRJ 33 would match a Middle Miocene age. The palaeothentids found at PRJ 25 and PRJ 33’ localities cannot be considered for biostratigraphic inferences, since they were found outside a stratigraphic context. Nevertheless, these paucituberculatans considerably add to our knowledge, as they are the first ever recorded in Brazilian Amazonia

A skull of the extinct tayassuid Brasiliochoerus stenocephalus (Lund in Reinhardt, 1880) (Mammalia, Cetartiodactyla) from the Late Pleistocene of southern Brazil: morphology and taxonomy

Among the several fossils of South American tayassuids, it is remarkable the presence of a well-preserved skull from southern Brazil (Chuí Creek, Santa Vitória do Palmar, Santa Vitória Formation). Here, we provide an update in the taxonomic arrangement and anatomical description of this specimen assigned to Brasiliochoerus stenocephalus based on the combination of the following traits: 1) long rostrum with a markedly convex profile; 2) anterior margin of the orbits located behind the vertical plane of the distal part of M3; 3) facial crests of the zygomatic arch forming an angle of about 80° relative to the molar series; 4) postorbital process more developed and ventrally projected in comparison to other tayassuids; 5) absence of a sagittal crest and presence of short parasagittal crests; 6) presence of curved temporal crests; 7) accentuated basicranial flexion; 8) bunodont and brachydont cheek teeth; 9) conspicuous pneumatization; 10) short postcanine diastema; and 11) cranium with no postorbital depression. This specimen was collected from sedimentary levels that contain a diverse assemblage of Pleistocene terrestrial mammals. Based on living analogous species, the presence of this taxon indicates dry and relatively open environments at some part of the Late Pleistocene in the study area.Fil: Copetti, Paula Lopes. Universidade Federal de Santa Maria; BrasilFil: Gasparini, Germán Mariano. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Departamento Científico de Paleontología de Vertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Pereira, Jamil Corrêa. Museu Coronel Tancredo Fernandes de Mello; BrasilFil: Fontoura, Emmanuelle. Universidade Federal de Santa Maria; BrasilFil: Lopes, Renato Pereira. Universidade Federal do Rio Grande do Sul; BrasilFil: Kerber, Leonardo. Universidade Federal de Santa Maria; Brasi

A Phase II Study to Evaluate the Safety and Efficacy of Prasinezumab in Early Parkinson's Disease (PASADENA) : Rationale, Design, and Baseline Data

Altres ajuts: F. Hoffmann-La Roche Ltd.Background: Currently available treatments for Parkinson's disease (PD) do not slow clinical progression nor target alpha-synuclein, a key protein associated with the disease. Objective: The study objective was to evaluate the efficacy and safety of prasinezumab, a humanized monoclonal antibody that binds aggregated alpha-synuclein, in individuals with early PD. Methods: The PASADENA study is a multicenter, randomized, double-blind, placebo-controlled treatment study. Individuals with early PD, recruited across the US and Europe, received monthly intravenous doses of prasinezumab (1,500 or 4,500 mg) or placebo for a 52-week period (Part 1), followed by a 52-week extension (Part 2) in which all participants received active treatment. Key inclusion criteria were: aged 40-80 years; Hoehn & Yahr (H&Y) Stage I or II; time from diagnosis ≤2 years; having bradykinesia plus one other cardinal sign of PD (e.g., resting tremor, rigidity); DAT-SPECT imaging consistent with PD; and either treatment naïve or on a stable monoamine oxidase B (MAO-B) inhibitor dose. Study design assumptions for sample size and study duration were built using a patient cohort from the Parkinson's Progression Marker Initiative (PPMI). In this report, baseline characteristics are compared between the treatment-naïve and MAO-B inhibitor-treated PASADENA cohorts and between the PASADENA and PPMI populations. Results: Of the 443 patients screened, 316 were enrolled into the PASADENA study between June 2017 and November 2018, with an average age of 59.9 years and 67.4% being male. Mean time from diagnosis at baseline was 10.11 months, with 75.3% in H&Y Stage II. Baseline motor and non-motor symptoms (assessed using Movement Disorder Society-Unified Parkinson's Disease Rating Scale [MDS-UPDRS]) were similar in severity between the MAO-B inhibitor-treated and treatment-naïve PASADENA cohorts (MDS-UPDRS sum of Parts I + II + III [standard deviation (SD)]; 30.21 [11.96], 32.10 [13.20], respectively). The overall PASADENA population (63.6% treatment naïve and 36.4% on MAO-B inhibitor) showed a similar severity in MDS-UPDRS scores (e.g., MDS-UPDRS sum of Parts I + II + III [SD]; 31.41 [12.78], 32.63 [13.04], respectively) to the PPMI cohort (all treatment naïve). Conclusions: The PASADENA study population is suitable to investigate the potential of prasinezumab to slow disease progression in individuals with early PD. Trial Registration: NCT03100149