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ABSTRACT. A new rhynchosaur, Hyperodapedon huenei sp. nov., is described from the Upper Triassic Santa Maria Formation of the Parana  Basin, Brazil. The holotype is an almost complete skull and mandible, collected at Inhamanda Â, in the state of Rio Grande do Sul, Brazil. The diagnosis of the genus Hyperodapedon Huxley is revised to include not only H. huxleyi Lydekker and H. gordoni Huxley (as generally accepted), but also the new species described here, various specimens usually assigned to`Scaphonyx ®scheri' Woodward, and`S'. sanjuanensis Sill. H. huenei sp. nov. exhibits a number of plesiomorphic features and appears to be the least derived species of Hyperodapedon, forming a sister taxon to the remaining members of the genus. A preliminary phylogenetic analysis for the more derived rhynchosaurs is presented.`Scaphonyx' sulcognathus Azevedo and Schultz represents the sister taxon of Hyperodapedon, while`Rhynchosaurus' spenceri Benton is considered to be a more derived Middle Triassic rhynchosaur.

Detailed description of the cranial anatomy of the rhynchosaur previously known as Scaphonyx sulcognathus allows its assignment to a new genus Teyumbaita. Two nearly complete skulls and a partial skull have been referred to the taxon, all of which come from the lower part of the Caturrita Formation, Upper Triassic of Rio Grande do Sul, southern Brazil. Cranial autapomorphies of Teyumbaita sulcognathus include anterior margin of nasal concave at midline, prefrontal separated from the ascending process of the maxilla, palatal ramus of pterygoid expanded laterally within palatines, dorsal surface of exoccipital markedly depressed, a single tooth lingually displaced from the main medial tooth-bearing area of the maxilla, and a number of other characters (such as skull broader than long; a protruding orbital anterior margin; anguli oris extending to anterior ramus of the jugal; bar between the orbit and the lower temporal fenestra wider than 0·4 of the total orbital opening; mandibular depth reaching more than 25 of the total length) support its inclusion in Hyperodapedontinae. T. sulcognathus is the only potential Norian rhynchosaur, suggesting that the group survived the end-Carnian extinction event.

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Until now the Doswelliidae was considered a monospecific family including Doswellia kaltenbachi from the Late Triassic of North America. The phylogenetic position of this taxon remained enigmatic until recently, when a sister-group relationship with the Proterochampsidae was suggested. In the present contribution we describe the new doswelliid species Archeopelta arborensis gen. et sp. nov. from the Middle-Late Triassic of Brazil. A cladistic analysis recovered Archeopelta, Doswellia, and Tarjadia within a monophyletic group of basal archosauriforms, the Doswelliidae. The monophyly of this family is supported by the presence of osteoderm ornamentation that is coarse, incised, and composed of regular pits and the presence of an unornamented anterior articular lamina. Archeopelta is more closely related to Doswellia than to other archosauriforms by the presence of basipterygoid processes anterolaterally orientated, dorsal centra with a convex surface, width of the neural arch plus ribs of the first primordial sacral that are three times the length of the neural arch, and iliac blade laterally deflected, with strongly convex dorsal margin, and a length less than three times its height. The phylogenetic analysis indicates that Doswellidae is the closest large monophyletic entity to Archosauria, which achieved a wide palaeolatitudinal distribution during the late Middle and Late Triassic time span.

-New discoveries of articulated skulls and lower jaws of Brasilodon and Brasilitherium from the Late Triassic of Brazil provide additional information on these small cynodonts, allowing us to establish the family Brasilodontidae nov. The basicranium, lateral wall of the braincase, primary and secondary palates and the quadrate of Brasilitherium are described, as well as the basicranium, primary palate and lower jaw of Brasilodon. Brasilitherium exhibits more derived characters than Brasilodon in the periotic, the promontorium, and the articular process of the dentary. Brasilodon is more derived in the lower dentition, the mode of tooth replacement, and the vascular features in the "stapedial recess". Both genera have interpterygoid vacuities that are considered here as possibly derived or reversed characters of the mammalian primary palate. The new phylogenetic analysis presented here corroborates the position of both genera as sister-group of mammals as previously proposed.Keywords: Cynodontia, Probainognathia, Brasilodon, Brasilitherium, Late Triassic, southern Brazil.RESUMO -Novos achados, incluindo crânios com mandíbulas articuladas, de Brasilodon e Brasilitherium do Neotriássico do Brasil fornecem informações adicionais sobre estes pequenos cinodontes, permitindo a proposição de uma nova família, Brasilodontidae. São descritos o basicrânio, a parede lateral da caixa craniana, o palato primário e o secundário e ainda o quadrado de Brasilitherium, bem como o basicrânio, o palato primário e a mandíbula de Brasilodon. Brasilitherium apresenta caracteres mais derivados em relação a Brasilodon no periótico, promontório e processo articular do dentário. Brasilodon apresenta uma dentição mandibular mais derivada, bem como o padrão de substituição dentária e ainda o sistema vascular relacionado ao recesso estapedial. Ambos apresentam vacuidades interpterigóides, que são aqui interpretadas como uma característica derivada ou uma reversão, diretamente relacionada à organização do palato primário mamaliano. A nova análise filogenética aqui apresentada confirma a proposição deste dois gêneros constituírem o grupo-irmão dos mamíferos, como já foi proposto em trabalhos prévios.Palavras-chave: Cynodontia, Probainognathia, Brasilodon, Brasilitherium, Triássico superior, sul do Brasil.

In this contribution we report the first occurrence of the enigmatic African probainognathian genus Aleodon in the Middle-early Late Triassic of several localities from the state of Rio Grande do Sul in southern Brazil. Aleodon is unusual among early probainognathians in having transversely-expanded postcanine teeth, similar to those of gomphodont cynognathians. This genus was previously known from the Manda Beds of Tanzania and the upper Omingonde Formation of Namibia. The Brazilian record of this genus is based upon multiple specimens representing different ontogenetic stages, including three that were previously referred to the sectorial-toothed probainognathian Chiniquodon theotonicus. We propose a new species of Aleodon (A. cromptoni sp. nov.) based on the specimens from Brazil. Additionally, we tentatively refer one specimen from the upper Omingonde Formation of Namibia to this new taxon, strengthening biostratigraphic correlations between these strata. Inclusion of A. cromptoni in a phylogenetic analysis of eucynodonts recovers it as the sister-taxon of A. brachyrhamphus within the family Chiniquodontidae. The discovery of numerous specimens of Aleodon among the supposedly monospecific Chiniquodon samples of Brazil raises concerns about chiniquodontid alpha taxonomy, particularly given the extremely broad geographic distribution of Chiniquodon. The discovery of Brazilian Aleodon and new records of the traversodontid Luangwa supports the hypothesis that at least two subzones can be recognized in the Dinodontosaurus Assemblage Zone.