The Santa María Amajac paleolake is located in the central portion of Hidalgo, Mexico. Twenty-seven fossil taxa of aquatic and terrestrial plants, gastropods, ostracods, amphibians, and mammals identified previously in the area of the paleolake were selected and their distribution in America during the Late Pliocene-Pleistocene was analyzed using the panbiogeographic method. As a result of the overlap of 27 individual tracks, 5 generalized tracks were obtained: I) Western North American, II) Central North American, III) Eastern North American, IV) Mesoamerican, and V) South American. The generalized tracks are consistent with previous proposals for extant gymnosperms, amphibians, sauropsids, birds, mammals, aquatic plants, insects, beetles, and nematodes, suggesting that distribution patterns have prevailed since the late Pliocene (Blancan). Four biogeographic nodes were identified, 2 situated in North America, in California and Colorado, the third located in the Santa María Amajac area in central Mexico, and the fourth located in Central America.

The northeastern part of Algeria is characterized by Meso–Cenozoic fossiliferous deposits. All the previous studies have been focused on invertebrate and vertebrate body fossils from this region. In the present paper we provide the first ichnological study from the region of Ouenza, Tebessa Wilaya (northeastern Algeria). An ichnoassemblage composed of eight ichnotaxa, namely cf. Archaeonassa isp., Arenicolites isp., Diplocraterion isp., Helminthopsis isp., Palaeophycus tubularis, Skolithoscf. linearis, cf. Taenidium isp., and Thalassinoides isp., reported from the lower Langhian (Middle Miocene) of Aïn Sidi Salah locality (Tebessa Basin) is discussed. These trace-fossils belong to the Skolithos and proximal Cruziana ichnofacies indicating deposition within a shallow marine (littoral). The large size of Thalassinoides suggests well-oxygenated setting, under moderate- to high-energy conditions, with occasional storm events. Keywords: trace-fossils, paleoenvironments, shallow marine, Middle Miocene, Tebessa.

The State of San Luis Potosí, Mexico, is rich in fossils and has a long-standing tradition of paleontological research. Nevertheless, most of these studies have been focused on vertebrates and invertebrates body fossils, with the ichnological record being overlooked. Here, we report the occurrence of ichnofossils (Diplocraterion parallelum, Ophiomorpha nodosa, Skolithos linearis, and Palaeophycus tubularis) from the Upper Cretaceous (Maastrichtian) Cárdenas Formation, southeastern San Luis Potosí. Invertebrate trace fossils and associated body fossils suggest that the Cárdenas Formation was deposited in a low to high energy system, with occasional storm events, in a shallow water platform (delta plain or coastal paleoenvironment influenced by tidal action).

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This paper documents the occurrence of Skolithos linearis, Planolites beverleyensis, and Thalassinoides isp. in the Cárdenas Formation (Late Cretaceous), southeastern San Luis Potosí, central Mexico. This is the second record of S. linearis for this lithological unit, while P. beverleyensis and Thalassinoides isp. are documented for the very first time in this formation. The ichnoassemblage is referred to the Cruziana Ichnofacies which, in concert with associated invertebrate body fossils (Exogyra costata), suggest a shoreface setting with moderate- to low-energy conditions and episodic storms.