O DEVONIANO NO ESTADO DO MATO GROSSO DO SUL, BRASIL: NOVA ÁREA DE DISTRIBUIÇÃO E PRESENÇA DE TÍPICA FAUNA MALVINOCÁFRICA

Devonian strata are widely known for the eastern edge of the Paraná Basin, particularly in the state of Paraná. However, studies are still scarce on the northwestern border, especially in the state of Mato Grosso do Sul. During the studies, around 120 geological and paleontological sites in the region were identified, and some discrepancies were identified in the distribution maps of the Devonian units (Campos Gerais / Chapada Group) in that state. This paper presents a review on the Devonian strata distribution in Mato Grosso do Sul state, as well a survey of paleontological works in the region of occurrence of the climax Malvinokaffric fauna (Pragian-early Emsian) in order to increase the discussion about the genesis of Devonian deposits. This fauna, combined with other stratigraphic evidences, corroborates a non-compartmentalization of the Paraná Basin for this age. The hypothesis of a tectonism concomitant with the deposition of the Ponta Grossa Formation (=lower Chapada II Group) is raised, mainly to the top of the unit, corroborated by a progradational context followed by a depositional hiatus during the middle Emsian at the end of the Eifelian in the area. It is possible that the Campo Grande Arch only acquired geomorphological expressiveness during the middle Emsian which would be attested by the absence of strata dated as late Emsian / Eifelian in croping areas in the state.

New Early Devonian (late Emsian) placoderms from Belarus

Four placoderm fishes are described from the Lepel Beds of the Vitebsk Regional Stage of the Lower Devonian (upper Emsian) of Belarus. Two forms are new (Stipatosteus svidunovitchi new genus, new species and Actinolepis zaikai new species) and the other two taxa are left in open nomenclature (Coccosteidae gen. indet. sp. indet.; Placodermi indet. 1). Specimens of all four forms consist of disarticulated, mostly well-preserved plates (some are worn at the edges) originating from the cores of six boreholes. Additionally, the paper presents data on organic remains with the placoderms. A detailed lithological description of the enclosing rocks and a taphonomic description of the ichthyofauna are also provided. The 2010 Stratigraphic Chart of the Devonian deposits of Belarus was used as the stratigraphic basis. The presence of the genus Actinolepis Agassiz, 1844 in these deposits as well as in the Emsian of the Baltic region and Spitsbergen suggests a regional paleogeographic connection at this time.UUID: http://zoobank.org/368b44df-e9e9-417c-a0e0-f7e138b7f4ec