Primitive echinoderm - solved!!! + Hyolitha + Orthocerida...

Spectacular complete specimen of Nimchacystis agterbosi. In addition, the plates contain several specimens of hyoliths (Hyolitha) and a specimen of an indeterminate orthocerid. Nimchacystis is a primitive and enigmatic echinoderm that lived during the Ordovician. The specimen is perfectly preserved, the body, the appendage, and the distimose are visible. The Nimchacystis animal is a primitive echinoderm of the Soluta group. Nimchacystis had an ovoid body, a feeding appendage inserted laterally, and a twisted and flattened dististel. These animals are interpreted as active epibenthic detritivores that feed on detritus and use their distiteles to drag themselves across soft substrates. Also preserved are several specimens of Cavernolites senex, a primitive and enigmatic hyolith (Hyolitha) that lived during the Ordovician. The specimen is perfectly preserved. Hyoliths (Hyolitha) are a class of small conch-bearing tommophores that lived in the Paleozoic era. Their calcareous shells, probably aragonitic, are conical, with triangular or semicircular cross-sections and usually flattened on the ventral side. They possessed a cover or operculum, typically articulated. The taxonomic position of hyoliths has long been uncertain, until in 2017 their inclusion in Lophophorata, a group that includes brachiopods and bryozoans, was established thanks to the study of specimens preserving soft-tissue impressions. The Cavernolites animal was solitary, epibenthic and semi-sessile, i.e., living on the seabed substrate with very limited mobility, and were suspension feeders, feeding on particles suspended in water trapped by the lophophore tentacles. There is a plate and a counterpart plate. Specimens with this preservation are extremely rare. The contrast between the fossils and the matrix is spectacular. The extraordinary preservation of the fossils allows observation in great detail of the delicate structures of Nimchacystis and Cavernolites. The preparation of the specimens has been extremely laborious, as the fossils are extremely delicate. A specimen worthy of a Museum. Measurements of Nimchacystis: 70 x 15 mm Length of indeterminate orthoceratid: 45 x 15 mm Plate 1: 1182 g; 17 x 13.5 x 3 cm Plate 2: 678 g; 14 x 13 x 3 cm Plastic stands included. The Fezouata Formation quarries, near the Moroccan city of Zagora, are yielding a rich and varied fossil record with extraordinary preservation, so that even soft parts or soft-bodied animals are recorded with some frequency. This type of preservation is similar, though later in time, to that of the famous Burgess Shale (Canada). These fossils are between 480 and 472 million years old. At that time Morocco was an ocean and located near the South Pole.

Schätzpreis:€160

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