Kingdom Animalia Class Trilobita Suborder Agnostina Rank Genus | Phylum Arthropoda Order Agnostida Superfamily Agnostoidea | |
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Toragnostus is a genus of trilobites restricted to the late Middle Cambrian. Its remains have been found in the United States, Greenland, Denmark, China, Sweden, the Russian Federation, and Kazakhstan. Its headshield and tailshield are almost completely effaced and it has two thorax segments.
Contents
Distribution
Description
Like all Agnostida, Toragnostus is diminutive, with the headshield (or cephalon) and tailshield (or pygidium) of approximately the same size (or isopygous) and outline. Like all Agnostina, Toragnostus has only two thorax segments. The cephalon and pygidium are almost completely effaced, lacking a cephalic border and with wide pygidial border. The cephalon is strongly convex. The central raised area of the cephalon (or glabella) is outlined at the rear, narrow and tapering forward. It carries an elongated median node, clearly in the front half of the cephalon. The pygidial axis (or rhachis) is very broad, with the frontal lobe (M1) defined by a furrow crossing the axis. There is a weak elongated node on the rhachis.