Daguinaspis ambroggii. Cambrian Souss Lagerstätte.

Restoration details: No restoration at all in the specimen. The plate was slightly prepared in order to try to display the pygidium, which, even though, is not fully visible (a particularly common characteristic of Daguinaspis fossils).

Dimensions of specimen and matrix: See scale on the photo.

Identification:
Daguinaspis ambroggii (Hupé & Abadie, 1950).

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

Lithostratigraphy: Upper Amouslek Formation (Lower Cambrian, Stage 3).

Biostratigraphy: Daguinaspis Zone of the Souss Fossil Lagërstatte.

Age: Cambrian, Early Paleozoic Era. 520-515 million years old.

Collection: #CALPAIS 8532; Collected on May 2021.

Description: One typical complete adult internal mold of D. ambroggii, with ca. 3 cm length (see the scale on the photo). On the same slab are observable disperse partial sclerites and little parts of incomplete rostral plates of other Fallotaspidids. All the exoskeleton shows a yellow color, due to the replacement of the original cuticular substances by argillaceous, phosphatic and ferritic minerals. Note the presence, particularly in some thoracic segments and a few pleurae, of unstable calcite. In general, the specimen is well preserved, showing almost all the key structures of the species.

Cephalon typical from one adult individual, heart-shaped, showing one single small facial suture, coincident with the preglabellar ridge. Glabella and occipital ring eroded, as the majority of the specimens of this species show. The concave preglabellar frontal area till the eyes is clearly observable. The prominent ocular lobes, so typical from Daguinaspis, are slightly eroded but well marked and elevated from the rest of the cephalon.

Thorax is almost complete, especially on the right lobe. Observable 1st-15th of the 16 thoracic segments. Conspicuous pleurae (although some incomplete on the left lobe), with non-evident pleural spines (not preserved). Well marked axial furrows on the posterior tergites. Note the sequence of pleural flanges (that allowed the weak enrolment of the species) on both lobes.

The pygidium is not observable. Despite their small size (know from few individuals), Daguinaspis (and other Fallotaspidid) pygidia are surprisingly rare. On the other hand, there is no clear deformation of the exoskeleton of this specimen, which is difficult to get.