on March 28, 2022

    Hupetina antiqua (Sdzuy, 1978) adult (cf.) specimen.

    Restoration details: No reconstructions at all in this slab.

    Dimensions: Specimen: 1,0 x 0,5 cm; Matrix:


    Locality: Tazemmourt Section, Northen slope of the Western Anti-Atlas, Morocco.

    Species: Hupetina antiqua (Sdzuy, 1978); Family: Bigotinidae; Order: Ptychopariida; Class: Trilobita.

    Lithostratigraphy: Igoudine Formation of Tazemmourt Section (Early Lower Cambrian, Stage 3).

    Biostratigraphy: Hupetina antiqua Zone of the Cambrian Souss Fossil Lagërstatte.

    Age: Cambrian, Early Paleozoic Era. 521-515 million years old.

    Collection: #CALPAIS 8487; Collected on May 2021.

    Description (main features):
    Probable adult complete internal mould, with exoskeleton well preserved, exception made to the glabella, slightly eroded.
    Conspicuous determination characteristics that are obviously present:
    - Intraocular cheek with an outline similar to an isosceles right triangle (or a quarter of a circle), but with slightly curved outer margin;
    - Anterior border with a distinct pointy angulation on the sagittal line; the anterior margin to the left and right side of this kink are almost straight;
    - Eye ridges with initial part almost contacting the anterior part of the frontal glabellar lobe;
    - Eye ridges almost straight, directed distinctly rearward from near frontal lobe;
    - Lateral furrows not visible in this specimen;
    - Palpebral lobes relatively short and very conspicuous in this specimen, in a distinctly posterior position;

    Hupetina antiqua is a scarce species with one extremely high geologic interest. It is the oldest described trilobite from Morocco (520.27 + 0.59/− 0.57 Ma strata, already precisely dated with U–Pb radioisotopic Cambrian volcanic zircons (Landing et al, 2020)) and it is among the Earth’s oldest trilobites, if not the oldest one. Hupetina antiqua has been accepted to define the beginning of Cambrian Stages 3 on West Gondwana.

    Collector evaluation: 8 on 10 due to the lack of definition of the glabellar lobes.

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