Trilobites
Order Corynexochida, Suborder Illaenina, Superfamily Illaenoidea,
Family Thysanopeltidae
Geologic Age: Middle Devonian
Trilobite
is 53 mm long
Jebel Oufaten, Alnif, Morocco
Remarks: Like the majority of trilobites, Scabriscutellum had holochroal
eyes with many
fine facets. Holochrocal eyes have a very tight hexagonal packing of
small facets with a single corneal
layer covering the many lenses. Many living arthropods have compound
eyes that are very sensitive to motion. It is presumed that these were
as well,
enabling them to quickly spot an approaching predator - trilobites
putatively adapted this trait early in evolution. Also note the heavy
ribbing of the pygidium. Scabriscutellum is distinguished from Thysanopeltis
by a lack of pygidial fring spines , and from Scutellum
by the ribbing of the
pygidium.
Also see:
Moroccan Trilobites |