- China, Sweden, the
Russian Federation, and Kazakhstan. Its
headshield and
tailshield are
almost completely effaced and it has two
thorax segments. T. bituberculatus...
- (or pleurae) are furrowed, and the
articulating facets distinct. The
tailshield (or pygidium) is
always smaller than the
headshield (or cephalon), a situation...
- a small,
rather flat
trilobite with an oval outline, a
headshield and
tailshield of
approximately the same size, 7
articulating segments in the middle...
- may have an exta
large and wide rib (a
state called macropleural). The
tailshield (or pygidium) is
small but
appears to be
composed of more than one segment...
- oval or semi-circular
headshield (cephalon), and a
circular to long oval
tailshield (pygidium)
equal to or
longer than the cephalon,
without any body segments...
- laterally. This so-called
vindicular furrow serves to lock the rim of the
tailshield to the
headshield when the
trilobite is enrolled. The
axial rings of the...
-
headshield (or cephalon) is
almost entirely effaced and
wider than the
tailshield (or pygidium). The
pygidium is also very effaced, but the
ovate pygidial...
-
thorax segments, a
totally effaced headshield (or cephalon),
while the
tailshield (or pygidium)
although effaced, has a
clear furrow parallel to its border...
- (Newfoundland). It can be
recognized by its
strongly effaced headshield and
tailshield, with
narrow but
distinct furrows and
borders along its margins, and three...
- long (genal)
spines extending from the side of the
cephalon back to the
tailshield (or pygidium). The
frontal margin of the
cephalon is
semicircular to parabolic...
