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New arthropods and problematica from the Ordovician of Morocco
Peter Van Roy
Research Unit Palaeontology, Department of Geology and Soil Sciences, Ghent
University, Krijgslaan 281 / S8, B-9000 Ghent, Belgium <peter.vanroy@rug.ac.be>
The shallow marine coarse clastics of the Upper Ordovician Upper Ktaoua Formation in south-eastern Morocco (Erfoud-Rissani-Alnif-Zagora area) have recently been shown to contain fossils of soft-bodied and poorly sclerotized organisms in association with more classical shelly elements and trace fossils. Preservation of soft tissues in the Moroccan sites is strikingly similar to that of some of the more resistant “frond-like” Ediacaran organisms. Most of the Moroccan fossils do not seem to have been transported before burial.
Represented by over fifty specimens from three sites, cheloniellids belonging to Duslia are the most numerous among the newly discovered arthropods. This genus was hitherto only known from the Czech Republic. Some Moroccan specimens preserve the gut as a fine sedimentary infill. Other arthropod fossils include rare fragments of possible aglaspidid and eurypterid affinity and, from the Zagora area, a single complete specimen of a possible basal chelicerate.
With several hundreds of specimens collected from four sites, soft-bodied paropsonemid eldonioids are the most abundant fossils. The in situ preservation of these otherwise rare problematica suggests a benthic mode of life for these animals.
Co-occurring at three sites with the paropsonemids are discoidal fossils of uncertain affinities, showing similarities to both Protolyellia and Ediacaria booleyi.
Estratto da: The Palaeontological Association
45th Annual Meeting
15th-19th December, 2001
Geological Museum
University of Copenhagen
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 "Eldonioid102")
Club Paleontologico Italiano
