0000000000394179
AUTHOR
Khadija El Hariri
Pseudoskirroceras, a remarkable but poorly known Early Pliensbachian Tethyan ammonite genus: New data from the High Atlas (Morocco).
13 pages; International audience; The discovery of new Early Pliensbachian ammonite faunas in Central High Atlas (Morocco) allows the re-examination of the taxonomic, stratigraphical and palaeogeographical framework of the genus Pseudoskirroceras, an intriguing but until now poorly known Tethyan taxon. For the first time, several specimens of Pseudoskirroceras mastodon (Fucini, 1935) the type species of the genus, have been collected in a well-known stratigraphical context. This material allows the evaluation of intra-specific variability and consequently the assessment of the taxonomical relevance of various geometrical and ornamental features. The best diagnostic features are the clearly …
Les ammonites du Pliensbachien du jebel Bou Rharraf (Haut Atlas oriental, Maroc).
60 pages; International audience; L'originalité des dépôts sédimentaires et des faunes d'ammonites du jebel Bou Rharraf repose sur la présence de faciès « Ammonitico Rosso », les plus occidentaux connus pour le Pliensbachien, une forte diversité des Phylloceratida (Phylloceras, Calaiceras, Zetoceras, Partschiceras et Juraphyllites) et une disparité morphologique importante chez les Galaticeras, Miltoceras et les Tauromeniceras. Si quelques formes, telles que Miltoceras taguendoufi et Mauretaniaceras elmii nov. gen., nov. sp. ont un cachet endémique très affirmé, les faunes du Pliensbachien du Haut Atlas oriental sont classiques pour la marge sud de la Téthys occidentale. Trois genres (Callo…
Exceptionally preserved soft parts in fossils from the Lower Ordovician of Morocco clarify stylophoran affinities within basal deuterostomes.
10 pages; International audience; The extinct echinoderm clade Stylophora consists of some of the strangest known deuterostomes. Stylophorans are known from complete, fully articulated skeletal remains from the middle Cambrian to the Pennsylvanian, but remain difficult to interpret. Their bizarre morphology, with a single appendage extending from a main body, has spawned vigorous debate over the phylogenetic significance of stylophorans, which were long considered modified but bona fide echinoderms with a feeding appendage. More recent interpretation of this appendage as a posterior “tail-like” structure has literally turned the animal back to front, leading to consideration of stylophorans…
Sédimentologie et quantification de la subsidence des séries liasiques dans le Haut Atlas Central marocain (coupe de Foum Zabel, région de Rich).
13 pages; International audience
Endemism as a palaeobiogeographic parameter of basin history illustrated by early- and mid-Liassic peri-Tethyan ammonite faunas
Abstract Episodes of endemism during Sinemurian–Pliensbachian times are described from synthetic data (publications and unpublished collections) about ammonite faunas of the western reaches of the Tethys. The Lusitanian, Sub-Betic and High Atlas basins receive special attention. The study shows that (1) endemism occurs principally in the Lusitanian and High Atlas basins, which are the most confined palaeogeographic structures; (2) it tends to occur synchronously in different basins but involving different taxa, i.e. it is independent of phylogeny; (3) it is not obviously correlated with relative sea-level at any given time. However, the fact that episodes of endemism coincide with second-or…