The Malvinokaffric Realm is an endemic paleogeographic region that inhabited Gondwanan high latitude seas during Early-Middle Devonian times. The causes for the collapse of this fauna are still debated but seem to be related to a transgressive event during Middle Devonian in the Chaco and Paraná basins in Bolivia and Brazil, which probably generated warmer water currents into the seas bearing Malvinokaffric fauna. This study applies ichnology as a relative proxy to better understand the impact of the main paleobiological events in the collapse of the Malvinokaffric Realm. Eight Devonian ichnoguilds are recognized in this study (Asterosoma, Glossifungites, Macaronichnus, Phycosiphon, Planolites, Skolithos, Teichichnus, and Zoophycos), and their stratigraphic distribution was compared with macrofossil distribution in Paraná Basin. The Pragian to Middle Emsian strata represent the climax of the diversity of body and trace fossils, recording distinct invertebrate life habits; the Asterosoma and Skolithos ichnoguilds predominate in the southern and northwestern borders, respectively, the last representing proximal settings. The “first decline” in Malvinokaffric diversity is diagnosed during the Eifelian, after an extensive regressive event during the late Emsian characterized by the reduction in different life habits, mostly suspension- and detritus-feeding. Trace fossils represent the Planolites ichnoguild principally, and the Eifelian strata are virtually absent on the northwest edge close to the paleo-basin flanks. The Givetian interval is characterized by the most expressive flooding event (Káčak event) that connected several Gondwanic basins, allowing the presence of extra-Malvinokaffric taxa in the Paraná Basin. Trace fossils are represented chiefly by the Phycosiphon ichnoguild in the Eifelian–Givetian boundary in the southern edge, and Planolites, Asterosoma, and Skolithos ichnoguilds in the upper strata. Finally, the Frasnian strata were diagnosed only to the northwestern edge of the basin, presenting a very low macrofossil diversity (e.g., lingulids and Australocoelia), and a low-ichnodiversity progradational trend from Phycosiphon to Skolithos ichnoguild. The identified paleoenvironmental changes evidences that the Early Devonian shallow seas (Jaguariaíva Member) were impacted by a gradual increase in freshwater input towards the Middle Devonian.

Malvinokaffric领域是一种流行的古地理地区，在泥盆纪中早时期就居住在冈瓦纳高纬度海域。该动物群崩溃的原因仍在争论中，但似乎与玻利维亚和巴西Chaco和Paraná盆地中泥盆纪期间发生的海侵事件有关，这可能导致带有马尔维诺科动物群的海流变暖。这项研究应用鱼类学作为相对替代，以更好地了解主要古生物学事件对马尔维诺卡菲地区崩溃的影响。这项研究中认可了八种泥盆纪鱼类协会（Asterosoma，Glossifungites，Macaronichnus，Phycosiphon，Planolites，Skolithos，Teichichnus和Zoophycos），并将其地层分布与巴拉那盆地的大化石分布进行了比较。普拉格期至中埃西亚期地层代表着人体和痕迹化石多样性的高潮，记录了独特的无脊椎动物生活习性。在Asterosoma和Skolithos ichnoguilds分别占主导地位的南部和西北部边境，最后代表近端设置。在艾菲尔时期后，在艾菲尔时期被诊断出马尔维诺夫族多样性的“首次下降”，这是在艾美斯晚期发生了一次广泛的退化事件之后，其特征是不同的生活习惯减少了，主要是悬浮和碎屑喂养。微量化石代表浮游生物ichnoguild主要位于伊比利亚地层，而在靠近古盆地的西北侧，西北边缘几乎没有。Givetian区间的特征是连接几个冈第瓦尼盆地的最具表现力的洪水事件（Káčak事件），使得巴拉那盆地中存在马尔文诺法克里奇类群。迹化石被表示由主要Phycosiphon在南部边缘艾菲尔-Givetian边界ichnoguild，和Planolites，Asterosoma，和Skolithos在上层ichnoguilds。最终，仅在盆地西北缘诊断出了弗拉西尼亚地层，表现出非常低的大型化石多样性（例如，舌质和古猿属）），以及从Phycosiphon到Skolithos ichnoguild的低鱼类种群进化趋势。所确定的古环境变化表明，早泥盆纪浅海（Jaguariaíva成员）受到向泥盆纪中部的淡水输入逐渐增加的影响。