Plate sections of saccocomid crinoids spotted in the Albian carbonate deposits of the Georgetown Formation from Sierra Azul (Coahuila, NE, Mexico) are reported and described. These microfossil remains consist of discarded proximal plates and partial thecae, i.e. primibrachial plates and radial pieces of a partial cup. These roveacrinoids are associated with calcisphere blooms and an abundant diversified planktic foraminiferal assemblage, mostly consisting of favusellids. All these features are evidence of a high primary productivity within an unstable deepening environment. Such pelagic crinoids have been so far regarded as opportunistic organisms that thrived during transgressive eustatic levels and phyto-planktic blooms, in abundance/accumulation events all indicative of hypoxic conditions. The overall microfossil assemblage assigns to this finding an Albian-Early Cenomanian age. Such an event might be well correlated and/or contemporaneous to the bundle of hypoxic events known as OAE1. Such saccocomid plates in Albian deposits revive the debate on the transition between the late Jurassic genera (Saccocoma Agassiz and Crassicoma Sieverts-Doreck & Hess, in Hess) and the late Cretaceous ones (mainly Applinocrinus Peck).

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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.