LICHIDA (Moore, 1959)
A typical feature of the representatives of this
order is the closely granulated (Granum, Lat. grain) or tuberculated
(Tuberculum, Lat. tuberculum) exoskeleton.
As a rule, cephalon, thorax or pygidium are spined
The LICHIDA are including the Superfamilies Lichoidea,
Odontopleuroidea and Dameselloidea.
The images shows a
representative of the Superfamily Lichoidea (Family Lichidae).
(Source: Trilobites, Levi-Setti,
A great Glabella which extends up to the anterior
cephalic border is typical. The development and differentiation of the
Cephalons ranges from simple up to complex structures. The
As a rule, the eyes (holochroal) are present, developed however mostly
smallish. The LICHIDA have a
development varies and the thorax is composed of 8- 13 segments. The
pleura are normally ending in pleural spines that for their part are
varying in length and development again. Furthermore rachis and pleura
featuring dorsal sided spines is possible.
exception of the representatives of Odontopleuroidea (very small
pygidium), the big tail shield is designed often longer than broad. The
pygidial edge can feature spinous structures. One finds 3 pairs of
pleura, passing into spines (variable design).