The outline of the
exoskeleton of
Meteoraspis is an elongate, slightly inverted egg shaped though almost ovate, widest at the tip of the genal spines and 1.6× as long as wide. The headshield (or
cephalon) is highly vaulted. The well-defined central raised area (or
glabella) is convex, elongate tapering, with a rounded front, and has only one furrow, crossing it near the back of the cephalon, defining the occipital ring. A node may be present on the occipital ring. The remaining parts of the cephalon, called fixed and free cheeks (or fixigenae and librigenae) are upsloping. The fracture lines (or
sutures) that in moulting separate the librigenae from the fixigenae are divergent just in front of the eyes, becoming parallel near the border furrow and slightly convergent at the margin. From the back of the eyes the sutures follow a lazy S-curve, diverging first more outward and near the margin more backward, cutting the posterior margin within the inner bend of the spine (or
opisthoparian sutures). Uniquely, the furrow parallel to the margin (or border furrow) has 2 not very noticeable pits in front of the glabella, and rarely a very faint 3rd median pit. There are no ridges that connect the eye to the glabella. The medium-sized eyes (over ⅓× the length of the glabella) are slightly behind the middle of the glabella. Genal angle ending in short spines extending backward about one thorax segment. The articulating middle part of the body (or
thorax) has 13 segments. The axis is convex, and less than ½× as wide as each of the so-called pleurae to its sides. Segments pointed sideways with a rounded front (a shape called falcate). The tailshield (or
pygidium) is about ½× as wide as the cephalon, almost twice as wide as long, excluding the two flat, shark tooth shaped, widely spaced spines. The axis in the pygidium is 1¼× longer than wide, with almost parallel sides, almost reaching the rear margin, with 3 or 4 axial rings; 3 sets of interpleural grooves and pleural furrows ending at distance of the margin. There is no furrow that would define a border in the pygidium.
Comparison with Tricrepicephalus Species of the related genus
Tricrepicephalus can be differentiated from those of
Meteoraspis by having three equally prominent pits in the anterior border furrow, a much less vaulted cephalon, with spines reaching at least to the third thorax segment, 12 thorax segments and two long, tubular, curved pygidial spines that are reminiscent of the pincers of an
earwig. == Reassigned species ==