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Neorylstonia nom. nov. pseudocolumellata, a replacement name for Mesophyllum pseudocolumellatum Beauvais, 1986, is only known from uppermost Sinemurian to uppermost Pliensbachian (Lower Jurassic) strata of Morocco. This solitary coral species went extinct during the Pliensbachian-Toarcian transition (~183.5 My), which is currently considered to be a second order biodiversity crisis linked to a period of rapid and global paleoenvironmental disturbances. Neorylstonia pseudocolumellata has a distinctive skeletal organization. The axial structure of the corallite, which has no equivalent in Mesozoic taxa, is reminiscent of the skeletal organization of some Paleozoic rugose corals such as Amygdalophyllum Dun and Benson, 1920, or Rylstonia Hudson and Platt, 1927. This similarity is based on the occurrence of a calicular boss also named pseudocolumella. As Rugosa and Scleractinia do not appear closely related, we consider that this feature cannot be due to evolutionary inheritance from a Rugosan ancestor. The morphological aspects of the skeleton have been assessed in order to understand the function and growth of this axial "calicular boss" as well as to more precisely describe the genus and species characters. The organization of the septal apparatus points to a typical Scleractinian pattern, which is also supported by the original aragonitic mineralogy of the skeleton. This implies a convergence phenomenon, leaving open the question of the functional significance of such a calicular organization. We posit that this feature was used for sexual reproduction and so did not always develop in a population.

During the Early Jurassic, reefs in the shallow seas of the Atlas Rift experienced substantial changes as they recovered from the end-Triassic mass extinction. Excellent Lower Jurassic reef deposits documenting this change occur in the Central High Atlas region of Morocco, and herein we describe Owl Olistolith, a micro-olistolith found in lower Pliensbachian-aged (∼ 188.7 million years ago) Moroccan strata. The olistolith records the composition of a reef that grew within the Atlas rift zone and represents a snapshot of reef recovery ∼ 10 million years after the end-Triassic mass extinction. Owl Olistolith is derived from a reef that was originally situated on an outer platform within fair weather wave base; it broke loose and was transported to deeper water and deposited amongst marls. Corals and microbialites formed the primary framework of the reef; microproblematica, foraminifera, and other minor components were also present. The reef can be divided into two dominant facies: a microbialite facies that contains no corals (54%–94% microbialites), and a coral-microbialite facies with substantial proportions of both microbialite (23%–50%) and corals (14%–72%). The micro-olistolith contains at least 15 distinct coral types. In this study, seven coral genera were identified, three of which represent taxa that span the Triassic/Jurassic boundary, including Coryphyllia, Stylophyllopsis, and Margarosmilia. These results indicate that, although surviving taxa played a significant role, newly evolved corals were the most important taxa in the reestablishment of reef ecosystems in the Early Jurassic of Morocco.

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