28 research outputs found
Extending the footprint record of Pareiasauromorpha to the Cisuralian : earlier appearance and wider palaeobiogeography of the group
Pareiasauromorpha is one of the most important tetrapod groups of the Permian. Skeletal evidence suggests a late Kungurian origin in North America, whereas the majority of occurrences come from the Guadalupian and Lopingian of South Africa and Russia. However, Pareiasauromorpha footprints include the ichnogenus Pachypes, which is unknown from strata older than late Guadalupian. A revision of several Pachypes-like footprints from the Cisuralian-Guadalupian of Europe and North America confirm the occurrence of this ichnogenus and of the ichnospecies Pachypes ollieri comb. nov. beginning in the Artinskian. This is the earliest known occurrence of Pachypes and it coincides with the Artinskian reptile radiation. Based on a synapomorphy-based track-trackmaker correlation, P. ollieri can be attributed to nycteroleter pareiasauromorphs such as Macroleter. Therefore, the earliest occurrences of pareiasauromorph footprints precede by at least 10 myr the earliest occurrence of this group in the skeletal record. Moreover, the palaeobiogeography of the group is extended to the Cisuralian and Guadalupian of western Europe
First occurrence of the lungfish Sagenodus (Dipnoi, Sarcopterygii) from the Carboniferous Lagerstätte of Montceau-les-Mines, France
New material of the dipnoan genus Sagenodus is described from the Carboniferous of the Barrat quarry (Blanzy-Creuzot coal basin, Montceau-les-Mines, France). This is the first occurrence of this lungfish in France, which enlarges its distribution within Europe (Fritsch, 1888; Schultze, 1993; Watson and Gill, 1923).
This material is Stephanian B in age, the previously established geological range of this Euramerican (Schultze and Chorn, 1997) genus. Remains consist of skull, lower jaw and shoulder girdle elements, closely set together with many ribs.
This material, considered as belonging to a single disarticulated specimen, presents affinities with the material of Sagenodus sp. from Germany (Schultze, 1993) and appears significantly different to all other known Sagenodus species. However this new material can only be attributed to Sagenodus sp. because of its incompleteness.
Montceau-les-Mines is interpreted as a freshwater environment deposit and the presence of Sagenodus in this locality confirms that most of the localities of Sagenodus are freshwater deposits. The strong affinities, existing between the material from France and Germany, indicate that there were solid hydrographic links between both basins during the Stephanian B–Upper Rotliegend period