Rare Ontogenic Series of Marsaisia devoillei (Geyer, 2020) | Souss Lagerstätte, Morocco | #PAIS9524 ************* A Cambrian Sea Open Fossil Book Unlock the ancient secrets of the Cambrian Sea with this stunning and rare Marsaisia devoillei fossil, presented as a complete part and counterpart specimen. This remarkable piece offers a unique, book-like presentation, where the two halves open to reveal a beautifully preserved trilobite on each side, offering a glimpse into a world over 500 million years old. The fossils are exquisitely detailed, showcasing the intricate segmentation and characteristic features of this extinct arthropod. This natural, lucky split of the rock matrix allows you to appreciate both the positive impression (part) and its negative cast (counterpart), making it a true scientific and aesthetic marvel. This specimen is not just a fossil; it's a tangible page from Earth’s earliest history, perfect for collectors, educators, and anyone fascinated by the dawn of complex life. Its dramatic presentation and exceptional preservation make it a centerpiece for any collection. Don't miss the opportunity to own a genuine "open book" from the Cambrian period. This is a rare and captivating piece of ancient life art, ready to be displayed and admired. ************** Description: A scientifically significant plate from the Lower Cambrian of Morocco – featuring the deposition of Marsaisia trilobites in the same place along the time. A rare example of an ontogenetic series on a single slab - adults, holaspids and meraspids trilobites. This exceptional plate features one adult specimen of Marsaisia devoillei, preserved as a complete exoskeleton with internal and external mold – consistent with ecdysial remains (exuvia). The second specimen is an incomplete cranidium of one holaspid stage, lying adjacent to dozens of thoracic tergites. A meraspid cranidium is yet observable—a Despujolsiid, very probably also Marsaisia, given the context. The adult individual shows strong subparallel terrace ridges, indicating growth lines. It shows 3D relief and natural articulation, indicating minimal transport and rapid burial. The co-occurrence of three developmental stages within the same matrix shows that the species moulds of all ages are buried in the same place over time. This makes the slab not only visually striking but also of high taphonomic and behavioural interest. At the plate are also present two (2) specimens of Brevipelta chouberti (Geyer, 1994), one early Brachiopod, only known from the Souss Lagerstatte. Morphology: Marsaisia devoillei is characterised by a long, tapering glabella, narrow pleurae, and a small, semi-circular pygidium (the only tergite not clearly visible in the adult specimen - maybe lost or inside the matrix). The 3D inflation of the axial lobe and well-preserved facial sutures highlight the exceptional preservation typical of the Souss Lagerstätte. Also note the conspicuous pleural spines with progressive growth up to the eleventh thoracic segment and sigmoidal anterior border of the first thoracic. Scientific Details Species: Marsaisia devoillei n. sp. (Geyer, 2020) Family: Despujolsiidae Order: Redlichiida Class: Trilobita Brevipelta chouberti (Geyer, 1994); Superfamily OBOLELLACEA Walcott and Schuchert, 1908 [nom. transl.]; Family OBOLELLIDAE Walcott and Schuchert, 1908 [in Walcott, 1908]; Order OBOLELLIDA Rowell, 1965; Class: Articulata; Phylum Brachiopoda. Lithostratigraphy: Upper Amouslek Formation Age: Lower Cambrian (Series 2, Stage 3) – ca. 520–515 million years old Biostratigraphy: Daguinaspis Zone, Issendalenian, from the Souss Fossil Lagerstätte Locality: Tazemmourt Section, Northern slope of the Western Anti-Atlas, Morocco Collection Code: #PAIS 9524 | Collected: April 2025 Upon request, we will provide the relevant scientific literature to the buyer, including Geyer & Landing (2021), Geyer et al. (2020a), and Geyer (2020). Dimensions & Condition Specimen 1 (Adult): 4,8 × 4,1 cm Specimen 2 (early holaspid): 14 mm cranidium width Specimen 3 (meraspid): 3,5 mm cranidium width Matrix size: 17,2 × 6,7 cm Weight: 1250 g Restoration: No restoration - untouched. Why This Stands Out? • Rare ontogenetic series: adult, immature and meraspid on the same slab, with perfectly aligned part and counterpart • Detached genae and missing librigenae on non-adult individuals – evidence of moulting (ecdysis) • 3D preservation, minimal compression • Freshly collected, fully documented provenance (#PAIS 9524, April 2025) • From the Tazemmourt Section – type locality of the Souss Lagerstätte • Museum-grade specimen at a very fair reserve price Don’t miss this opportunity to own a true milestone in early arthropod evolution. Questions? We’re happy to help. Contact us for additional photos, details, or scientific references. You can consult our feedback, studies and other fossils here: https://www.mediterranic.com/ or https://www.cambrian521.com/ High-resolution pictures available at: https://www.mediterranic.com/Souss-Lagerst%C3%A4tte-site/Trilobites/Family-Despujolsiidae/Marsaisia-devoillei/Marsaisia-devoillei-stock-in-Portugal/9524-Marsaisia-devoillei-part-and-counterpart-slab Shipping Worldwide registered shipping with a tracking number. For more on the Souss Lagerstätte, Despujolsiidae trilobites, and our full collection, visit: www.mediterranic.com | www.cambrian521.com ****************** Happy bidding from the Mediterranic team – may the right collector win!